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Mutagenicity and disinfection by‐products in surface drinking water disinfected with peracetic acid
Abstract
The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to those found with sodium hypochlorite (NaClO) and chlorine dioxide (ClO2). The Ames test, root anaphase aberration assay, and root/micronuclei assay in Allium cepa and Tradescantia/micronuclei test were used to evaluate the mutagenicity of disinfected samples. Microbiological tests were also performed, and disinfection by-products (DBPs) were identified using gas chromatography/mass spectrometry (GC/MS). A slight bacterial mutagenicity was found in raw lake and river water, and similar activity was detected in disinfected samples. A plant test revealed genotoxicity in raw river water, and microbiological analysis showed that PAA has bactericidal activity but lower than that of the other disinfectants. The DBPs produced by PAA were mainly carboxylic acids, which are not recognized as mutagenic, whereas the waters treated with the other disinfectants showed the presence of mutagenic/carcinogenic halogenated DBPs. However, additional experiments should be performed with higher concentrations of PAA and using water with higher organic carbon content to better evaluate this disinfectant.
... Previous studies on the toxicity of PAAs do not raise concerns for mutagenicity (Monarca et al., 2002;Monarca et al., 2003), carcinogenicity (Müller et al., 1988), or reproductive toxicity, and the lethal doses on the species studied are generally well above the concentrations of PAA used for disinfection (Kitis, 2004). The DBPs identified in the PAA-treated water were mainly carboxylic acids and aldehydes, which are readily biodegradable (Kitis, 2004) and recognized as non-mutagenic (Monarca et al., 2002;Monarca et al., 2003), and no halogenated compounds were found (Monarca et al., 2002). ...
... Previous studies on the toxicity of PAAs do not raise concerns for mutagenicity (Monarca et al., 2002;Monarca et al., 2003), carcinogenicity (Müller et al., 1988), or reproductive toxicity, and the lethal doses on the species studied are generally well above the concentrations of PAA used for disinfection (Kitis, 2004). The DBPs identified in the PAA-treated water were mainly carboxylic acids and aldehydes, which are readily biodegradable (Kitis, 2004) and recognized as non-mutagenic (Monarca et al., 2002;Monarca et al., 2003), and no halogenated compounds were found (Monarca et al., 2002). On the other hand, chlorine-based disinfectants produced some DBPs suspected of being mutagenic and carcinogenic (Monarca et al., 2002;Kitis, 2004). ...
... Previous studies on the toxicity of PAAs do not raise concerns for mutagenicity (Monarca et al., 2002;Monarca et al., 2003), carcinogenicity (Müller et al., 1988), or reproductive toxicity, and the lethal doses on the species studied are generally well above the concentrations of PAA used for disinfection (Kitis, 2004). The DBPs identified in the PAA-treated water were mainly carboxylic acids and aldehydes, which are readily biodegradable (Kitis, 2004) and recognized as non-mutagenic (Monarca et al., 2002;Monarca et al., 2003), and no halogenated compounds were found (Monarca et al., 2002). On the other hand, chlorine-based disinfectants produced some DBPs suspected of being mutagenic and carcinogenic (Monarca et al., 2002;Kitis, 2004). ...
... humic and fulvic acids), anthropogenic contaminants, chloride, bromide and iodide during the production of drinking water (Guzzella et al., 2006;Richardson, 2003) and the disinfection of wastewater (Dell'Erba et al., 2007;Liberti and Notarnicola, 1999;Nurizzo et al., 2005). It should be pointed out that the general criterion to identify a compound as a DBP is its greater presence in the treated water (at least two to three times) than in the raw water (by comparison of the chromatographic peak areas) (Monarca et al., , 2002: for this reason, in many studies the concentrations of the formed DBPs were not reported. Raw water (e.g. ...
... surface water for drinking water applications) can already contain several contaminants, which act as DBPs precursors or contribute as such to the toxicity of the effluents. Some of these compounds are aldehydes, aromatic compounds such as naphthalene, tert-butylbenzoic acid and pentafluorobenzaldehyde, phthalates (dimethyl phthalate), and alkanes such as 2,2,4,6,6pentamethylheptane and 2,2,4,4-tetramethyloctane (Dell'Erba et al., 2007;Monarca et al., 2002). ...
... Most of the DBPs identified during PAA disinfection are carboxylic acids, which are not recognized as mutagenic (Monarca et al., 2002;Richardson et al., 2007) and have also been reported as commonly formed during drinking water disinfection with other agents, such as ClO 2 , ozone and chloramines. Carboxylic acid concentration increases mainly due to the acetic acid present in the equilibrium solution and the decomposition of PAA (Luukkonen and Pehkonen, 2016). ...
Peracetic acid (PAA) has gained increasing attention over the last decades as a suitable and environmentally-friendly alternative to chlorine-based compounds for wastewater disinfection, claiming limited disinfection by-products (DBPs) formed and no persistent residues in the environment. The present work aims at presenting a comprehensive and updated review of the ecotoxicological effects of effluents treated with PAA, to be ascribed to residual PAA and hydrogen peroxide (H2O2) and DBP formation. Modest concentrations of DBPs have been observed after PAA treatment, mainly carboxylic acids, which are not recognized as genotoxic. Moreover, there is no evidence of any endocrine disruption potential of PAA in human health or in the ecotoxicological studies. The associated H2O2 fraction can potentially minimize the formation of halogenated DBPs and also contribute to the acute toxic effects of treated effluents. Effluents disinfected with PAA at concentrations typical of the wastewater treatment field have displayed limited toxic, mutagenic and genotoxic effects on different aquatic organisms, particularly low compared to chlorine-based disinfectants.
... For lake water disinfection, PAA generates fewer clastogenic/aneugenic substances than chlorine dioxide or sodium hypochlorite (Monarca et al., 2003). In addition, no halogenated DBPs were detected other than carboxylic acids in PAA treated surface water (Monarca et al., 2002). Also, no halogenated phenols were formed following PAA disinfection of a secondary wastewater effluent (Dell'Erba et al., 2007). ...
... For instance, the toxicities of PAA, UV light, ozone, and sodium hypochlorite against Ceriodaphnia silvestrii, Daphnia similis, Chironomus xanthus, and Danio rerio are in the order of free chlorine N ozone N UV N PAA (da Costa et al., 2014). In light of these findings, PAA is viewed as a promising alternative to chlorine-based disinfectants for water and wastewater disinfection (Guzzella et al., 2004;Monarca et al., 2002;Rossi et al., 2007;Stampi et al., 2002;Wagner et al., 2002). ...
Peracetic acid (PAA or CH3COOOH) is an emerging disinfectant with a low potential to form carcinogenic disinfection by-products (DBPs). Basic thermodynamic properties of PAA are, however, absent or inconsistently reported in the literature. This review aimed to summarize important thermodynamic properties of PAA, including standard Gibbs energy of formation and oxidation-reduction (redox) potential. The standard Gibbs energies of formation of CH3COOOH(aq), CH3COOOH(g), CH3COOOH(l), and CH3COOO(aq)- are -299.41kJ·mol-1, -283.02kJ·mol-1, -276.10kJ·mol-1, and -252.60kJ·mol-1, respectively. The standard redox potentials of PAA are 1.748V and 1.005V vs. standard hydrogen electrode (SHE) at pH 0 and pH 14, respectively. Under biochemical standard state conditions (pH 7, 25°C, 101,325Pa), PAA has a redox potential of 1.385V vs. SHE, higher than many disinfectants. Finally, the environmental implications of the thermodynamic properties of PAA were systematically discussed. Those properties can be used to predict the physicochemical and biological behavior of aquatic systems exposed to PAA.
... PAA is decomposed into water and acetic acid, which are not harmful products. Moreover, disinfection by-products (DBPs) formed by the reaction of PAA with organic matter mainly include carboxylic acids and aldehydes, which are less mutagenic and carcinogenic than halogenated DBPs generated from Effect of a Preharvest Peracetic Acid Treatment on the Natural Decay of Strawberries during Room-Temperature Storage chlorine-based disinfectants (Monarca et al., 2002;Crebelli et al., 2005) and are readily biodegradable (Kitis, 2004). In a study by Lee and Huang (2019), who analyzed the formation of DBPs during washing processes, a PAA treatment led to the formation of negligible levels of haloacetic acids, nitrogenous DBPs, and carbonaceous DBPs and fewer aldehyde DBPs than a sodium hypochlorite (NaOCl) treatment in both lettuce wash water and fresh-cut lettuce. ...
... PAA is approved by the Food and Drug Administration (FDA) for sanitizing and disinfection of food processing facilities and direct contact with food, and European approved for use in aquaculture. It becomes popular in aquaculture due to wide-ranging of antimicrobial effects, non-toxic degradation by-products and low environmental side effects [7][8][9]. In contrast, some hazardous and unsustainable common antimicrobial disinfectants (e.g., potassium permanganate, copper sulphate, chloramine and formaldehyde) can lead to markedly respiratory irritants and carcinogenic by-products in terms of worker safety and also having potential negative environmental impact on the receiving water body. ...
The effects of a peracetic acid-based disinfectant product (Aquastart®) were assessed on some hematological parameters, histological aspects and skin bacterial load of rainbow trout, likewise bacterial load of the rearing tank water. A total of 180 healthy rainbow trout weighing 124.65 ± 10 g were divided into two groups, each in three replicates in flow-through tanks. First group was exposed to Aquastart at 8.9 ppm for 30 min and second group was considered as the control. The fish were then reared for 60 days prior to sampling for hematological and histological studies. The lowest bacterial load level in both water columns and trout skin were observed in the treated trout (p < 0.05). Meanwhile, no significant impact on growth performance was recorded between treated and control fish. The immunocompetent cells population size in control fish were significantly lower than treated fish (p < 0.05). Histologically, no evidence of abnormality was seen in the gills, kidney, and liver tissues of treated fish. These results showed that application of Aquastart at 8.9 ppm is safe for use in flow-through tanks farming rainbow trout.
... The use of disinfectants comprising peracetic acid (PAA) and hydrogen peroxide (H 2 O 2 ) has increased in recent years because they have been shown to be highly efficient, broad-spectrum, and environmentally friendly [20][21][22], as after use, PAA can be decomposed into harmless components relatively quickly [23]. As the disinfection routines in food-processing facilities generally do not completely sterilize the processing surfaces, low numbers of bacteria remain after disinfection. ...
Pseudomonas spp. are the most commonly found bacteria in food-processing environments due to properties such as a high growth rate at low temperatures, a high tolerance of antimicrobial agents, and biofilm formation. In this study, a set of Pseudomonas isolates originating from cleaned and disinfected surfaces in a salmon processing facility were screened for biofilm formation at 12 °C. A high variation in biofilm formation between the isolates was observed. Selected isolates, in both planktonic and biofilm states, were tested for resistance/tolerance to a commonly used disinfectant (peracetic acid-based) and antibiotic florfenicol. Most isolates showed a much higher tolerance in the biofilm state than in the planktonic state. In a multi-species biofilm experiment with five Pseudomonas strains with and without a Listeria monocytogenes strain, the Pseudomonas biofilm appeared to aid the survival of L. monocytogenes cells after disinfection, underscoring the importance of controlling the bacterial load in food-processing environments.
... Compared with the current common disinfectants, although the disinfection effect of PAA is not ideal, the decomposition products of PAA are mainly acetic acid, hydrogen peroxide, oxygen and water, and the products are not toxic and secondary pollution [28,29]. Studies have shown that PAA does not produce toxic or mutagenic by-products when it reacts with organic matter in treated wastewater or drinking water and surface water [30,31]. Although the potential of PAA to produce harmful disinfection by-products cannot be completely ignored, the amount of disinfection by-products produced is far less than that of chlorine and ozone disinfectants [3]. ...
Peracetic acid (PAA) has broad application in disinfection, since it produces fewer disinfection by-products. In this study, PAA was used as a disinfectant to inactivate Escherichia coli, Staphylococcus aureus, and Bacillus subtilis under different pHs and turbidity. The effects of different environmental factors on PAA disinfection were compared. The results were fitted by the common disinfection kinetic models, and the CTs were finally calculated according to the disinfectant decay models and the optimal disinfection kinetic models. By comparing PAA with other common disinfectants, the projected application of PAA was discussed.
... Initially, no halogenated DBPs, such as trihalomethanes (THMs), were reported in PAAtreated surface water. 14 Shortly after, researchers corroborated those initial results and reported the formation of aldehydes in the order of μg/L. 15−17 On the contrary, later studies remarked that in the presence of chloride and phenol, PAAM is able to generate chlorophenols. ...
Peracetic acid has quickly gained ground in water treatment over the last decade. Specifically, its disinfection efficacy toward a wide spectrum of microorganisms in wastewater is accompanied by the simplicity of its handling and use. Moreover, peracetic acid represents a promising option to achieve disinfection while reducing the concentration of typical chlorination byproducts in the final effluent. However, its chemical behavior is still amply debated. In this study, the reactivity of peracetic acid in the presence of halides, namely, chloride and bromide, was investigated in both synthetic waters and in a real contaminated water. While previous studies focused on the ability of this disinfectant to form halogenated byproducts in the presence of dissolved organic matter and halides, this work indicates that peracetic acid also contributes itself as a primary source in the formation of these potentially carcinogenic compounds. Specifically, this study suggests that 1.5 mM peracetic acid may form around 1-10 μg/L of bromoform when bromide is present. Bromoform formation reaches a maximum at near neutral pH, which is highly relevant for wastewater management.
... Disinfection is mainly achieved by releasing oxygen radicals, causing oxidative disruption of cell membranes [11][12][13][14]. PAA is regarded as a promising disinfectant for improving biosecurity in aquaculture due to its broad spectrum of activity against several microorganisms, short contact time, low dependency on pH, and rapid degradation into harmless residues [15][16][17][18]. It is also identified as an alternative to H 2 O 2 since it degrades faster and presents a lower effective dose against many pathogens (1-2 mg L − 1 ) than H 2 O 2 , making it safer for the biofilter and therefore more suitable for application in RAS [19][20][21]. ...
Background: Fish encounter oxidative stress several times during their lifetime, and it has a pervasive influence on their health and welfare. One of the triggers of oxidative stress in fish farming is the use of oxidative disinfectants to improve rearing conditions, especially in production systems employing recirculation technology. Here we report the physiological and morphological adaptive responses of Atlantic salmon (Salmo salar L.) post-smolts to intermittent exposure to a potent oxidative agent peracetic acid (PAA). Fish reared in semi-commercial scale brackish water recirculating aquaculture system (RAS) were exposed to 1 ppm PAA every 3 days over 6 weeks. Mucosal and systemic responses were profiled before exposure, 22 and 45 days during the intermittent PAA administration.
Results: Oxidative stress was likely triggered as plasma antioxidant capacity increased significantly during the exposure period. Adaptive stress response to the periodic oxidant challenge was likewise demonstrated in the changes in plasma glucose and lactate levels. PAA-induced alterations in the transcription of antioxidants, cytokines, heat shock proteins and mucin genes showed a tissue-specific pattern: downregulation was observed in the gills and olfactory rosette, upregulation occurred in the skin, and no substantial changes in the liver. Further, PAA exposure resulted in histological changes in key mucosal organs (i.e. olfactory rosette, skin and gills); pathological alterations were predominant in the gills where cases of epithelial lifting, hypertrophy and clubbing were prevalent. In addition, intermittent PAA administration resulted in an apparent overproduction of mucus in the nasal mucosa. Lastly, PAA did not dramatically alter the ability of salmon to mount a physiological stress response in the presence of a secondary stressor, though some subtle interference was documented in the kinetics and magnitude of plasma cortisol and glucose response post-stress.
Conclusions:The present study collectively demonstrated that intermittent oxidant exposure was a mild environmental stressor that salmon could mount strong adaptive responses at systemic and mucosal levels. The results will be valuable in optimising the rearing conditions of post-smolts in RAS, especially in adopting water treatment strategies that do not considerably interfere with fish health and welfare.
... Additionally, PAA can be more effective than chlorine or UV for the inactivation of bacteria with antibiotic resistant genes (Di Cesare et al., 2016). Its primary advantage as an alternative to chlorine is that it does not form halogenated DBPs, a concern when chlorinating cyanobacteria cells because of the reaction between chlorine and released intracellular organic matter (Dell'Erba et al., 2007;Monarca et al., 2002;Xue et al., 2017). The use of PAA as a preoxidant is possible for controlling mussel growth in drinking water intakes (Hurtado et al., 2021) or reducing formation potentials of trihalomethanes and haloacetic acids, which were reduced by 41% and 56%, respectively, in one study (Griffin et al., 2018). ...
The reactivity of peracetic acid (PAA) alone, and PAA exposed to ultraviolet radiation (UV), was investigated on Microcystis aeruginosa cells, and on microcystin-LR and -RR. Reaction rates between PAA and MC-LR (k = 3.46 M⁻¹s⁻¹) and MC-RR (k = 2.67 M⁻¹s⁻¹) were determined in an unbuffered acidic solution, and they are approximately 35-45 times lower than a previously reported reaction rate between MC-LR and chlorine at pH 6. Peracetic acid reacted with M. aeruginosa cells as a function of PAA and cell concentrations, with 10 mg/L PAA resulting in 1-log reduction of total microcystin-LR within 15 min. Advanced oxidation by UV/PAA readily degraded MC-LR and MC-RR, outperforming UV/H2O2 at pH 7.7 by >50% on an equimolar basis. Indirect photolysis at this pH is due to •OH and organic radicals, as determined by trials in the presence of excess tert-butanol to scavenge •OH. The process is less effective when the pH departs from neutral conditions (5.9 or 10.6) due to the decreased effects of both radicals. These findings suggest that PAA alone might be a viable option for cyanobacteria and microcystins control in preoxidation applications and that UV/PAA is an effective process for degrading MC-LR and MC-RR at neutral pH.
... Effects of the chlorine dioxide and peracetic acid disinfectants on the microbial counts of the spinach Chlorine dioxide and peracetic acid are considered alternative sanitizers because of their strong oxidation capacities and lower risk of forming harmful by-products (Monarca et al., 2002;Silveira et al., 2008). Both disinfectants are safe and create environmentally friendly residues (Demirci & Ngadi, 2012). ...
Minimally processed fruits and vegetables are economically important commodities due to convenience, and healthiness, etc. These commodities are susceptible and shelf life limited as cut surfaces of vegetable result in microbiological and physiological spoilage. To extend the shelf life of Asian spinach vegetables, different washing treatments (i.e. tap water, chlorine dioxide, and peracetic acid) and packaging materials (i.e. Polypropylene-PP, High Density Polyethylene-HDPE and Low Density Polyethylene-LDPE) were evaluated in the study. The results obtained show that washing treatment of the Asian spinach with peracetic acid solution of 100 ppm for five minutes was effective due to reduced significantly E. coli and Coliforms counts. The Asian spinach was packed in HDPE material might optimally prolong the shelf life up to 7 days at 10±1oC.
... Of these antimicrobials, PAA is the most widely used sanitizer in apple packing lines during the spraybar brush bed intervention (Zhu et al., 2020). PAA has broadspectrum antimicrobial activity (Baert et al., 2009) and does not produce toxic by-products (Monarca et al., 2002). PAA applied at 80 ppm, a concentration approved by the Food and Drug Administration (FDA) to wash fresh produce without further rinsing requirement (FDA, 2017a), is more efficient in decontaminating L. monocytogenes on fresh apples compared with 100 ppm chlorine-based sanitizers (Shen et al., 2019;Sheng et al., 2020a). ...
Apples are naturally coated with a water-repelling hydrophobic wax layer, which may limit the antimicrobial efficacies of surface sanitizer solutions. Lauric arginate (LAE) is a cationic surfactant with antimicrobial efficacy against Listeria monocytogenes. In this study, we investigated the antimicrobial and the wettability effects of LAE in enhancing anti-L. monocytogenes efficacy of peracetic acid (PAA) and further verified the optimized treatment combinations in a pilot spray-bar brush bed system. Apples after 48 h of inoculation were treated with PAA surface sanitation in combination with different concentrations of LAE at 22 or 46°C. The effectiveness of PAA with LAE solutions in decontaminating L. monocytogenes significantly increased with the increased concentration of PAA (60–80 ppm) or LAE (0.01–0.05%) or the treatment temperature (from 22 to 46°C). A 30–120-sec wash by 80 ppm PAA with 0.01 and 0.05% LAE at 22°C reduced L. monocytogenes on apples by 2.10–2.25 and 2.48–2.58 log10 CFU/apple, respectively. Including LAE in the PAA solution decreased contact angles on apple surfaces. However, the increased wettability of the sanitizer solution may not be the main contributor to the enhanced antimicrobial efficacy of the PAA solution, given that the addition of Tween 80 or Tween 85 only slightly boosted the anti-L. monocytogenes efficacy of PAA solutions though both increased the wettability of the PAA solutions. The synergistic effects of PAA and LAE were further validated in a pilot spray-bar brush bed packing system, where a 30-sec spray wash with 80 ppm PAA and 0.05% LAE at 22 and 46°C caused 1.68 and 2.08 log reduction of Listeria on fresh apples, respectively. This study provides an improved PAA process/preventive strategy for ensuring microbial food safety of fresh apples that is applicable to commercial apple packing lines.
... Pure PAA has a stronger antimicrobial effect than hydrogen peroxide (Alasri et al. 1992), but hydrogen peroxide is an additional source of hydroxyl radicals, and the combination of both has synergetic effects (Flores et al. 2014). Unlike many other antimicrobial disinfectants, PAA is degraded mainly by chemical oxidation into harmless acetic acid and water, without toxic or harmful by-products (Monarca et al. 2002;Pedersen et al. 2009). Large doses of PAA (2.8-9.3 mg PAA L −1 ) are known to induce lethal effects on fish . ...
Fish is increasingly produced in recirculating aquaculture systems (RAS), which can offer some production and environmental benefits. Unfortunately, there is a tendency to develop off-flavors in RAS, mainly caused by geosmin (GSM) and 2-methyl isoborneol (MIB) accumulating in the fish flesh from the circulating water. These off-flavors are objectionable to consumers, reducing the profitability of production and causing an unwanted reputation for this fish production sector. In this study, combinations of oxidative chemicals: ozone (O3), hydrogen peroxide (H2O2), and peracetic acid (PAA) were applied in a commercial, full-scale (1.3 M kg a⁻¹) RAS rearing rainbow trout (Oncorhynchus mykiss). Inlet water from a nearby lake, circulating water, and depuration water were treated to increase their quality and enhance the depuration procedure. The results showed a decrease of 77% (MIB) and 93% (GSM) in the concentrations of off-flavors in circulating water after the treatments with oxidative chemicals.
... Therefore, it was suggested that strong disinfectants such as sodium hypochlorite, chlorine dioxide and peracetic acid might exhibit weak to moderate mutagenic effect. 42 Furthermore, these chlorinated-mutagenic compounds might have a carcinogenic effect or irritate mucous membranes in case of exposure according to a previous report. 43 Therefore, mutagenic or carcinogenic potential of EW is a critical safety concern for a disinfectant and wound healing agent designed for repeated use. ...
Over the last decade, electrolyzed water (EW) produced by salt and tap water has gained importance due to its antimicrobial effects. Regarding to chlorine-based compounds, EW also used in post-harvest safety of food processing and sterilization of surfaces. The latest studies suggested that EW might act as wound healing agent due to anti-infective and cell proliferative properties. In this study, we evaluated acute contact cytotoxicity in L929 mice fibroblast cells and wound healing activity of EWs in vitro. In addition, mutagenic activity was evaluated by Ames test with and without metabolic activation by S9 fraction and the stability profile of freshly prepared EWs has been followed up. According to the results, strong acid (StAEW) and mixed EW (MEW) showed dose-dependent cytotoxicity due to possible high HOCl concentration, while slightly acidic and catholyte EW (CEW) were not cytotoxic even applied directly for 30 sec. Further, StAEW and CEW showed a significant increase in L929 cell migration in scratch assay. Likewise, with/ without metabolic activation, neither of EWs had shown mutagenic profile in TA 98 and TA100 strains of Salmonella typhimurium. Follow-up of ORP (oxidation-reduction potential), pH and FCC (free chlorine concentration) showed that temperature and light were important storage conditions to maintain a stable profile particularly for ORP and FCC, which are the most important indicators for biological activity of EW. According to the present findings, it can be suggested that particularly StAEW, may represent a valuable wound healing agent with an achievable, economical and easy production system when stored under proper conditions.
... Particles were incubated in either municipal wastewater influent or pre-disinfection secondary wastewater effluent and reactors were either disinfected with PAA or not treated. PAA is considered a green disinfectant because it has not been reported to form regulated disinfectant by-products and was chosen due to its status as a disinfectant that will likely see increased use in the coming years (McFadden, Loconsole, Schockling, Nerenberg, & Pavissich, 2017;Monarca et al., 2002). PAA has a similar mechanism of disinfection to hypochlorite (Koivunen & Heinonen-Tanski, 2005;McFadden et al., 2017), as both oxidize cell membranes. ...
Microplastics (MP) have been proposed as a vector for pathogenic microorganisms in the freshwater environment. The objectives of this study were (a) to compare the fecal indicator growth in biofilms on MP and material control microparticles incubated in different wastewater fractions and (b) to compare MP biofilm, natural microparticle biofilm, and planktonic cell susceptibility to disinfection by peracetic acid (PAA). Biofilms were grown on high‐density polyethylene, low‐density polyethylene, polypropylene MP, or wood chips (as a material control) and incubated in either wastewater influent or pre‐disinfection secondary effluent. Reactors were disinfected with PAA, biofilms were dislodged, and total coliform and Escherichia coli were cultivated. Fecal indicators were quantifiable in both MP and wood biofilms incubated in the wastewater influent but only on the wood biofilms incubated in secondary wastewater effluent. More total coliform grew in the wood biofilms than MP biofilms, and the biofilms grown on MP and woodchips were more resistant to disinfection than planktonic bacteria. Thus, it may be possible to refer to the disinfection literature for fecal indicators in biofilm on other particles to predict behavior on MP. Treatments that remove particles in general would help reduce the potential for fecal indicator bypass of disinfection.
Practitioner points
• MP biofilm had lower concentrations of fecal indicators than wood biofilm
• Biofilm on MP was not more resistant to disinfection than wood biofilm
• Biofilms, regardless of substrate, were more resistant to disinfection than planktonic organisms
... Since 1897, chlorine-based compounds have been used for disinfection in drinking water treatment plants because of their excellent sterilisation efficiency and low cost. Nevertheless, the formation of disinfection by-products (DBPs) during chlorination is a cause for concern (Rook 1973;Monarca et al. 2002), and more than 300 different DBPs have been identified (Becher 1999). The two most common ones are the trihalomethanes and haloacetic acids, which have been associated with cancers such as bladder cancer (Bielmeier et al. 2001). ...
Chlorine-based compounds have been used as a disinfectant in drinking water treatment plants for decades because of their excellent sterilisation efficiency and low cost. However, the formation of disinfection by-products during chlorination is a cause for concern. Peracetic acid (PAA) is a strong oxidant with a redox potential higher than that of chlorine and does not form harmful disinfection by-products. It is thus a potential alternative for chlorine-based disinfectants. However, PAA decomposes rapidly in water at a rate that is highly affected by many factors, such as organic compounds and pH. The aim of this study is to investigate the stability of PAA during drinking water disinfection. To accomplish this, we studied methods for rapid detection of residual PAA and PAA decay in drinking water. Residual PAA was detected in water by the spectrophotometry-total chlorine reagent (SPTCR) method with a PAA concentration range of 0.090–10 mg/L (R2 = 0.9943). Decay tests of PAA in drinking water and other sources of water showed that the decay process conformed to the first-order kinetic model with fast and slow reactions. Among four factors, pH was the key factor in the decay process because an alkaline environment significantly promotes the decomposition of PAA. In addition, total organic carbon (TOC), conductivity, and initial PAA concentration also affected PAA decay. Experimental and statistical analyses suggested that these factors affected PAA decay in the following descending order of influence: TOC, initial PAA concentration, and conductivity. In real water matrices, the PAA decay rate increased with increasing initial PAA concentration.
... Several studies have shown that PAA produces almost no toxic or mutagenic degradation byproducts from the reaction with organic material present in the treated wastewater [16], if not in some cases mostly carboxylic acids, aldehydes and a few degradation byproducts interacting with amino acids, phenols, and other aromatic substances [17], generally not mutagenic. ...
Numerous substances from different chemical sectors, from the pharmaceutical industry to the many consumer products available for everyday usage, can find their way into water intended for human consumption and wastewater, and can have adverse effects on the environment and human health. Thus, the disinfection process is an essential stage in water and wastewater treatment plants to destroy pathogenic microorganisms but it can form degradation byproducts. Sodium hypochlorite is the most common disinfectant, but the most important drawback associated with this kind of compound is the generation of toxic disinfection byproducts. Many studies have been carried out to identify alternative disinfectants, and in the last few years, peracetic acid has been highlighted as a feasible solution, particularly in wastewater treatment. This study compares the transformations of five emerging pollutants (caffeine, tramadol, irbesartan, diclofenac, trazodone) treated with peracetic acid, to evaluate their degradation and the possible formation of byproducts with those obtained with sodium hypochlorite. Although peracetic acid has many advantages, including a wide field of use against microorganisms and a low toxicity towards animal and plant organisms, it is not as effective in the degradation of the considered pollutants. These ones are recovered substantially and are unchanged quantitatively, producing a very low number of byproducts.
... Treatment by means of chlorination, which is a widely employed method, has been reported to produce highly cytotoxic Plewa et al. 2002Plewa et al. , 2007, genotoxic (Plewa et al. 2010;Richardson et al. 2010), and c a r c i n o g e n i c ( H e r r e n -F r e u n d e t a l . 1 9 8 7 ) disinfection byproducts (DBPs). There have been reports of the formation of DBPs during disinfection by peracetic acid and ozonation; however, those DBPs are likely to be present in only trace quantities (Dell'Erba et al. 2007; Monarca et al. 2002;Sohn et al. 2004). Nearly 600 different types of DBPs are formed during water disinfection (Krasner et al. 2006), including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), nitrosamines, and bromate as the most prominent carcinogens to humans (Chowdhury et al. 2009). ...
Measurements of the UV–Vis absorbance (Abs) and intensity of fluorescence emission (Fluor), as well as of concentrations of total or dissolved organic carbon (OC) in aqueous samples are commonly used to estimate the potential for disinfection byproducts (DBPs) formation during water chlorination. In this work, based on 574 linear associations collected from 70 experimental research papers published over the period of 1997–2019, the strengths of the correlations of Abs, Fluor, and OC with DBPs concentrations are compared. The correlations were expressed as approximately normally distributed Z-scores using Fisher variance-stabilizing transformation. The effects of specific prediction method, chlorination agent, water source, and DBPs type, with consideration of possible effects due to the presence of bromide, are examined against Z-scores by ANOVA, testing main effects and some variables interactions. The performed analysis is a first attempt to expose differences and patterns in correlation strengths associated with DBPs formation, based on systematically covered broad existing literature. Abs and OC concentration of water samples tend to demonstrate the strongest correlations with DBPs formation as compared with specific UV absorbance (SUVA) or intensity of fluorescence emission. Correlations of DBPs formation during chloramination demonstrated weaker strengths as compared with other chlorination agents, suggesting more caution in predicting DBPs concentrations, based on simple descriptors such as Abs, OC, and Fluor. In a series of different water types, the correlations with DBPs formation are expected to be enhanced, when wastewater is chlorinated. Non-fluorescent matter may be an important contributor to DBPs formation during water chlorination. When fluorescence intensity is considered as a predicting tool, choosing humic-like rather than proteinaceous fluorescence may enhance the strengths of the correlations with DBPs formation. Different performances of Abs, OC, and Fluor in correlating with DBPs formation may be beneficial for their concurrent use helping to optimize removal of different DBPs precursors.
... Unlike many other antimicrobial disinfectants, PAA degrades mainly through chemical oxidation into harmless acetic acid and water, producing non-toxic or mutagenic by-products (Monarca et al., 2002). It has neither lethal effect on fish nor impairs nitrification in biofilters at low dosages (1 mg L −1 ) (Pedersen et al., 2009). ...
In recirculating aquaculture systems (RAS)s, off-flavors and odors, mainly caused by geosmin (GSM) and 2-methylisoborneol (MIB), can accumulate in the flesh of fish from RAS water, reducing the profitability of production. In this study, peracetic acid (PAA) was applied in three application intervals to pump sumps of rainbow trout (Oncorhynchus mykiss) reared in RAS. Using a real-time polymerase chain reaction (qPCR), the potential off-flavor producers were quantified using geoA and MIB synthase genes. Streptomyces was identified as the major GSM producer, and biofilters showed the highest number of potential off-flavor producers. Concentrations of GSM and MIB were analyzed in the circulating water and in the lateral part of the fish fillet. In water, concentrations up to 51 ng L ⁻¹ (GSM) and 60.3 ng L ⁻¹ (MIB) were found, while in the fillet, these were up to 9.8 ng g ⁻¹ (GSM) and 10.2 ng g ⁻¹ (MIB), decreasing with increasing number of PAA applications. PAA applications reduced the levels of off-flavor compounds, although this was insufficient to fully prevent the accumulation of GSM and MIB.
5-Fluorouracil and cyclophosphamide, the two most commonly used chemotherapeutic drugs, are widely detected in aquatic environments and cause cytotoxic and other adverse effects in ecosystems. In this work, UV/peracetic acid (UV/PAA) treatment was investigated for the first time for 5-fluorouracil and cyclophosphamide removal. The results showed that 5-fluorouracil and cyclophosphamide can be efficiently removed via UV/PAA within 20 min, with pseudo-first-order rate constants (kobs) of 0.197 and 0.135 min−1, respectively. The influences of PAA dosage, initial compound concentration, solution pH and common water constituents (Cl−, HCO3−, NO3− and dissolved organic matter) were systematically studied. radical dotOH was the predominant species involved in the degradation of the two pharmaceuticals, while direct UV photolysis and R–Cradical dot were also involved in removing 5-fluorouracil. Two and five byproducts were detected in UV/PAA degradation of 5-fluorouracil and cyclophosphamide, respectively, and the possible degradation pathways were proposed. Although total organic carbon was not completely removed during the reaction, the Microtox® toxicity trend (an increase and further decrease) implied further detoxification of the byproducts. Additionally, UV/PAA treatment applied to real water samples (river water and effluent from a wastewater treatment plant) still exhibited good efficiency for removing the two compounds, revealing its applicability in water/wastewater treatment.
Peracetic acid (PAA) is a commonly used antimicrobial in brush-bed spray bar interventions during apple packing. Prior to sanitizer application on the brush-bed, specific fruit cleaners, such as Acidex Duo (AD), EpiClean (EC), Nature's Shield 220-ACL (NS 220), or Nature's Shield 330-ALK (NS 330), are used to remove of soil, debris, and natural wax from the surfaces of apples. This study evaluated the effectiveness of commonly used cleaners in the apple industry to improve the antimicrobial efficacy of PAA against Listeria monocytogenes on apple surfaces during brush-bed spray bar interventions. Granny Smith apples, 48 h post-inoculation, underwent submersion treatment with different cleaners, as well as PAA alone or in combination with the cleaners. A 30-sec treatment of 5.0% AD, 4.2% EC, 10.0% NS 220, and 10.0% NS 330 resulted in 0.65, 0.50, 0.68, and 0.51 log10 CFU/apple reduction of L. monocytogenes on apples, respectively. Incorporating AD, NS 220, and EC significantly enhanced the antimicrobial efficacy of an 80 ppm PAA intervention. The enhancing effects were not impacted whether the cleaner was applied consecutively with PAA (sequentially) or in combination with PAA (simultaneously), nor were they impacted by a post-treatment water rinse. A 30-120 s wash of 80 ppm PAA with AD, EC, and NS 220 at their suggested concentration resulted in 2.46-2.55, 1.87-2.03, and 2.34-2.48 log10 CFU/apple reduction of L. monocytogenes, respectively, compared to 1.39-1.64 log10 CFU/apple in PAA treatment alone. The inclusion of AD or NS 220 in 80 ppm PAA solution resulted in a reduction of 1.51-1.63 log10 CFU/apple of Listeria after 30-60 s brush-bed spray wash. This enhancement in efficacy was significant compared to the treatment with 80 ppm PAA alone, which resulted in a reduction of 0.94-1.03 log10 CFU/apple. This study demonstrated that using certain commercially available cleaners along with PAA can enhance the effectiveness of PAA in reducing L. monocytogenes on fresh apples.
Disinfection is essential to swimming pool water (SPW) quality. Peracetic acid (PAA) has attracted attention for water disinfection for advantages such as less formation of regulated DBPs. Persistence kinetics of disinfectants is difficult to elucidate in pools because of the complex water matrix stemming from body fluid loadings from swimmers and long residence times. In this research, the persistence kinetics of PAA was investigated in SPW benchmarked against free chlorine, use bench-scale experiments and model simulation. Kinetics models were developed to simulate the persistence of PAA and chlorine. The stability of PAA was less sensitive to swimmer loadings than chlorine. An average swimmer loading event reduced the apparent decay rate constant of PAA by 66 %, a phenomenon that diminished with increasing temperatures. L-histidine and citric acid from swimmers were identified as main retardation contributors. By contrast, a swimmer loading event instantaneously consumed 70-75 % of the residual free chlorine. The required total dose of PAA was 97 % less than chlorine under the 3-days cumulative disinfection mode. Temperature was positively correlated with disinfectant decay rate, with PAA being more sensitive than chlorine. These results shed light on the persistence kinetics of PAA and its influential factors in swimming pool settings.
Under the influence of different types of disinfectants and disinfection environments, the removal level of pathogens and the formation potential of disinfection by-products (DBPs) will have a dual impact on the groundwater environment. The key points for sustainable groundwater safety management are how to balance the positive and negative relationship and formulate a scientific disinfection model in combination with risk assessment. In this study, the effects of sodium hypochlorite (NaClO) and peracetic acid (PAA) concentrations on pathogenic E. coli and DBPs were investigated using static-batch and dynamic-column experiments, as well as the optimal disinfection model for groundwater risk assessment was explored using quantitative microbial risk assessment and disability-adjusted life years (DALYs) models. Compared to static disinfection, deposition and adsorption were the dominant factors causing E. coli migration at lower NaClO levels of 0-0.25 mg/L under dynamic state, while disinfection was its migration factor at higher NaClO levels of 0.5-6.5 mg/L. In contrast, E. coli removed by PAA was the result of the combined action of deposition, adsorption, and disinfection. The disinfection effects of NaClO and PAA on E. coli differed under dynamic and static conditions. At the same NaClO level, the health risk associated with E. coli in groundwater was higher, whereas, under the same PAA conditions, the health risk was lower. Under dynamic conditions, the optimal disinfectant dosage required for NaClO and PAA to reach the same acceptable risk level was 2 and 0.85 times (irrigation) or 0.92 times (drinking) of static disinfection, respectively. The results may help prevent the misuse of disinfectants and provide theoretical support for managing twin health risks posed by pathogens and DBPs in water treatment.
Metal-based advanced oxidation processes (AOPs) with peracetic acid (PAA) have been extensively studied to degrade micropollutants (MPs) in wastewater. Mn(II) is a commonly used homogeneous metal catalyst for oxidant activation, but it performs poorly with PAA. This study identifies that the biodegradable chelating ligand picolinic acid (PICA) can significantly mediate Mn(II) activation of PAA for accelerated MP degradation. Results show that, while Mn(II) alone has minimal reactivity toward PAA, the presence of PICA accelerates PAA loss by Mn(II). The PAA-Mn(II)-PICA system removes various MPs (methylene blue, bisphenol A, naproxen, sulfamethoxazole, carbamazepine, and trimethoprim) rapidly at neutral pH, achieving >60% removal within 10 min in clean and wastewater matrices. Coexistent H2O2 and acetic acid in PAA play a negligible role in rapid MP degradation. In-depth evaluation with scavengers and probe compounds (tert-butyl alcohol, methanol, methyl phenyl sulfoxide, and methyl phenyl sulfone) suggested that high-valent Mn species (Mn(V)) is a likely main reactive species leading to rapid MP degradation, whereas soluble Mn(III)-PICA and radicals (CH3C(O)O• and CH3C(O)OO•) are minor reactive species. This study broadens the mechanistic understanding of metal-based AOPs using PAA in combination with chelating agents and indicates the PAA-Mn(II)-PICA system as a novel AOP for wastewater treatment.
A combination of graphene oxide quantum dots and peracetic acid (GQDs/PAA) was used to degrade sulfasalazine in municipal wastewater. The impact of reaction parameters such as initial concentrations of oxidant (peracetic acid) and drug (sulfasalazine) and different water matrices was evaluated. The degradation efficiency when using GQDs/PAA (50 mg/L: 0.10 mM) was almost 100% in synthetic water and 80% in municipal wastewater. The primary reactive radicals that caused the degradation of sulfasalazine in wastewater were identified as hydroxy (·OH) as well as the peroxy radicals (CH 3 C(=O)OO·, CH 3 C(=O)O·). 83.7% of total organic carbon were eliminated when 0.15 mM PAA was used while nearly 100% degradation of SZZ was achieved. A degradation pathway was proposed using the degradation intermediates obtained on quadrupole time-of-flight liquid chromatography mass spectrometry. The genotoxic and mutagenic potential of the degradation products formed during the degradation of sulfasalazine was assessed using the Ames test. It was demonstrated that none of the intermediates were mutagenic. GQDs/PAA was further tested as a potential disinfectant, and S. aureus was completely inactivated as verified by using LIVE/DEAD Bac light staining. In raw municipal wastewater, GQDs/PAA eliminated more than 90% of bacteria, thus confirming the synergy of GQDs/PAA as both a disinfectant and a photocatalyst.
Introduction
Peracetic acid (PAA) is a highly effective disinfectant against a wide range of viruses and bacteria. Its versatility, cost‐effectiveness, and ability to quickly decontaminate large areas make it an ideal choice. PAA is also environmentally friendly and safe, as it does not produce any harmful by‐products. However, to ensure its efficacy, it is crucial to maintain the optimal concentration of PAA in the solution.
Objective
The objective of the study is to investigate the use of attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy as a method for quantifying the concentration of peracetic acid (PAA), which comes in quaternary equilibrium mixture in commercial formulation. The study also aims to determine the rate constants and equilibrium constant for the production of PAA in various conditions, including the presence of catalyst and stabilizer.
Methods
The spectra of all chemicals in PAA solution obtained in FT‐IR Spectrometer were compared to identify the characteristic peaks of PAA, which were then computed using normal mode analysis at B3LYP/6‐31G(d) level by Gaussian 09. The ATR‐FTIR was used to measure time‐dependent PAA signals until they reached equilibrium in three different conditions: (1) Acetic acid (10 to 17.4 M) and hydrogen peroxide (5 M), (2) with sulfuric acid as catalyst, and (3) with phosphoric acid as stabilizer. The collected data was analyzed through regression analysis, in which curves and rate law formulas were fitted to obtain the rate constants for peracetic acid synthesis and hydrolysis.
Results
This study shows that ATR‐FTIR spectroscopy can detect and quantify peracetic acid with a characteristic peak at 1753 cm ⁻¹ . The proposed method is applicable to all peracetic acid solutions, including those with stabilizers and catalysts. The ATR‐FTIR method offers advantages such as short detection time, simple operation, small sampling volume, and accurate measurement. Moreover, the accuracy of this quantitative method is confirmed by the fact that the reaction rate constants deduced from the fitted curves are more consistent with the actual reaction rate constants than those of the reference data based on KI titration method.
This thesis focuses on the adverse effects of by-products formed during chlorine, ozone, and peracetic acid disinfection of wastewater. Chlorine is the most used form of chemical disinfection, but it reacts with disinfection by-products precursors to form trihalomethanes and haloacetic acids, which have shown to be carcinogenic, mutagenic, genotoxic, cytotoxic, and teratogenic in mostly rodent and some human studies. While ozone is more reactive than chlorine, it produces disinfection by-products such as formaldehyde, bromate and N-nitrosodimethylamine, which was found to be mostly carcinogenic, neurotoxic and, mutagenic in animal and human studies. Formaldehyde was the only disinfection by-product found to be classified as a Group 1 human carcinogen by the World Health Organization. Peracetic acid produces disinfection by-products such as carboxylic acid and aldehydes, but in very limited or undetectable amounts. There was no evidence indicating that carboxylic acid causes adverse effects to humans or animals. The use of pre-treatments, followed by physical forms of disinfection, such as UV radiation and membrane filtrations, combined with chemical disinfection was found to be the most useful and effective method to control/remove disinfection by-products and their precursors from treated wastewater.
As a major biological hazard, foodborne pathogens infect 48 million people annually, and are a major food safety concern in the U.S. Applying antimicrobial chemical agents is still an effective approach to control foodborne pathogens during food processing. Peroxyacetic acid (PAA) is an organic peroxide based, colorless liquid with a low pH and a strong, pungent, vinegar-like odor, which is formed from the chemical reaction of acetic acid and hydrogen peroxide (H2O2). Commercial PAA products contain all three chemicals in an aqueous solution often with stabilizers added, which can exert antimicrobial activity against microorganisms. PAA are approved by the US Food and Drug Administration (FDA) and US Department of Agriculture-Food Safety and Inspection Services (USDA-FSIS) for use as a generally recognized as safe (GRAS) antimicrobial agent on meat, poultry and egg products with the concentrations between 0.005 to 0.2%. This review provides detailed summaries of antimicrobial activities of PAA and H2O2 alone or in combination on fresh produce, meat and poultry products, and eggs against foodborne pathogens. This information is useful for food processors in the development of operational procedures for applying PAA and H2O2 during post-harvest food processing to control foodborne pathogens on food products.
Pollution of wastewater and natural waters by organic contaminants is a major health issue, yet actual remediation methods are limited by incomplete removal of recalcitrant contaminants and by secondary pollution by chlorinated contaminants and catalytic metals. To attempt to solve these issues, we tested the removal of acid orange by peracetic acid (PAA), a safe oxidant, activated by Fe-biochar that iron anchored on biochar to prevent secondary pollution by iron. Fe-biochar was synthesized using a simple, one-step pyrolysis method. We investigated the effects of PAA concentration, pH, humic acids, chloride, bicarbonate on the reaction. Radical quenching and electron paramagnetic resonance were used to identify reacting species. Results showed that the granulous structure of Fe-biochar and the presence of Fe, Fe3O4, Fe2O3, and Fe3C on Fe-biochar surface. The highest removal of acid orange of 99.9% was obtained with 1.144 mM PAA and 0.3g/L Fe-biochar at pH 7. Acid orange removal increases with Fe-biochar dose, decreases with pH, is slightly inhibited by humic acids and bicarbonate, and is not modified by chloride. Our experimental results suggest that CH3C(O)OO· and CH3C(O)O· are the main radical species, but there may also be non-radical effects in Fe-biochar/PAA process. Fe-biochar displays high re-usability, with 92.8% removal after five uses.
Bacterial and fungal pathogens in recirculating aquaculture and egg incubation systems can cause elevated mortality and decreased production. Peracetic acid (PAA) is a relatively low‐cost, safe, and effective disinfectant; however, its toxicity to early life stages of the Atlantic salmon (Salmo salar) has not been assessed. The 24‐h LC50 value of PAA was determined for three early life stages of Atlantic salmon: eyed eggs, fry (~0.17 g), and fingerlings (~16.3 g). LC50 values were calculated using the Trimmed Spearman‐Karber (TSK) method and Toxicity Relationship Analysis Program (TRAP). TRAP LC50 values for eyed eggs treated for 5 and 10 min were 781.5 and 485.0 mg/L PAA, respectively, while TSK LC50 values for eyed eggs treated for 5 and 10 min were 771.1 and 462.1 mg/L PAA, respectively. TRAP LC50 values for fry and fingerlings were 4.0 and 5.3 mg/L PAA, respectively, while TSK LC50 values for fry and fingerling were 4.1 and 5.3 mg/L PAA, respectively. The no observed effect concentration (NOEC) values for eyed eggs treated for 5 and 10 min were 500 and 300 mg/L PAA, respectively. These LC50 and NOEC values provide guidance for developing safe PAA treatment protocols Atlantic salmon eggs, fry, and/or fingerlings.
The use of chlorine (NaOCl) as a disinfectant for disinfection of food surfaces and decontamination of vegetables, fruits and seafood products was very popular in industrial processes. In recent years, many studies have however reported that the use of chlorine may lead to the formation of disinfection by-products (trihalomethane, as possibly carcinogenic to humans) when high amounts of organic matter are present in the wash water. Chlorine dioxide (ClO2) and peracetic acid (C2H4O3) were thus suggested to be alternative disinfectants for the decontamination of food. The main objective of this study was to evaluate the disinfection efficacy of chlorine dioxide and peracetic acid on Asian spinach. Chlorine dioxide and peracetic acid were evaluated at 25-100 ppm at contact time of 1-5 min. The results obtained revealed that the disinfection efficacy was depended on disinfectants, concentration and contact time. The total mesophillic counts, and of the Asian spinach vegetables treated with either chlorine dioxide or peracetic acid were significantly lower than that of the vegetables washed in tap water (p<0.05). Washing with chlorine dioxide and peracetic acid (100 ppm for 5 min) resulted in a reduction of total mesophillic counts (0.64 and 0.49), (0.75 and 0.99) and (1.31 and 1.63 log CFU/g, respectively) on the Asian spinach. In addition, application of both mentioned disinfectants did not significantly affected the sensorial quality of the Asian spinach (p>0.05). Despite the high cost, the alternative of peracetic acid could be a good option for processors.
The ever‐increasing need for access to safe water has meant that alternative water sources and innovative water reclamation approaches are often required to meet the global water demand. As a result, many wastewater treatment facilities have faced regulatory pressure to seek alternative disinfection methods that ensure public health safety, while adhering to regulations that set limits on carcinogenic disinfection by‐products (DBPs). Peracetic acid (PAA) is an emerging wastewater disinfectant in the United States that has been widely used in other industries such as food sanitization and does not produce carcinogenic DBPs. However, several factors such as transport, storage, and physical and chemical effects have stymied its widespread use in wastewater markets. Therefore, the purpose of this study was to examine the antimicrobial efficacy of an on‐site generated PAA compared against a commercially available PAA. Antimicrobial efficacy was assessed using standard fecal contamination indicators (i.e., total coliforms and Escherichia coli ) in six urban wastewater treatment facilities ranging in size and treatment processes. Overall, few statistical differences were found between the antimicrobial efficacies of on‐site generated PAA and commercially available PAA; however, before becoming more widely utilized, the on‐site PAA should be tested against emerging fecal contamination indicators (e.g., human norovirus and enterovirus) and be assessed in terms of economic and sustainability impacts.
Practitioner Points
Alternative Ct approaches should be considered when using disinfectants like PAA.
On‐site generated PAA can achieve the same level of disinfection as commercial PAA.
On‐site generation of PAA may help further its use as a wastewater disinfectant.
Chytridiomycosis is an emerging infectious disease threatening amphibian populations worldwide. While environmental disinfection is important in mitigating the disease, successful elimination of Batrachochytrium dendrobatidis (Bd) without excessively harming ecosystems is challenging. We selected peracetic acid (PAA) as the most potent of six commercially available products regarding their ability to inhibit growth of a highly virulent Bd strain. PAA killed Bd after 5 min of exposure to approximately 94.7 mg/L. We examined the toxicity of PAA against three invertebrate species and Discoglossus pictus tadpoles. 93% of invertebrates, but none of the tadpoles survived 5 min of exposure to 94.7 mg/L. Tadpoles showed no adverse effects after 5 min exposure to concentrations of approximately 37.9 mg/L or lower. Addition of PAA to aquatic microcosms decreased pH, while dissolved oxygen (DO) initially increased. Degradation of PAA reversed the pH drop, but caused a massive drop in DO, which could be remedied by aeration. As proof of concept, microcosms that were aerated and treated with 94.7 mg/L PAA sustained survival of tadpoles starting 48 h after treatment. Disinfecting aquatic environments using PAA could contribute to mitigating chytridiomycosis, while preserving at least some invertebrate diversity, but requires temporary removal of resident amphibians.
Postharvest diseases are a limiting factor in the storage of fresh blueberries. Gray mold caused by Botrytis cinerea and Alternaria rot caused by Alternaria spp. are important postharvest diseases in blueberries grown in California. Control of these fungal pathogens is generally dependent on preharvest sprays of synthetic fungicides, but in California multiple fungicide resistance has already developed in those pathogens, leading to the failure of disease control. Therefore, alternatives to synthetic fungicides are needed for the control of postharvest diseases. Peroxyacetic acid (PAA) is a disinfectant agent that poses low risk to human health. In this study, we evaluated the effects of postharvest use of PAA at 24 µL L-1 and 85 µL L-1 on fruit decay caused by fungal pathogens and quality of stored blueberry fruit. PAA treatment was applied to four cultivars over three seasons using two methods, dipping or spraying. Dipping blueberries compared to spraying them with PAA and its application at 85 µL L-1 were the most effective treatments. For example, when applied to ‘Snowchaser’ blueberries, this combination reduced naturally occurring decay after four weeks of storage at 0-1°C from 14.3% among water treated controls to 2.7% in 2018, and from 25.7% among water treated controls to 8.6% in 2020. In general, PAA did not adversely affect fruit quality or sensory quality of blueberries. Postharvest use of PAA appears to be a promising means to reduce postharvest decay of blueberries. To reliably obtain an acceptable level of disease control, the best use of PAA may be in combination with other practices rather than its use alone.
Disinfection is one of the most critical processes for municipal wastewater treatment. However, traditional chemical dosing approaches do not consider how changes in water quality and process operation can alter disinfection performance. This work aims to develop novel disinfection models for precise prediction of peracetic acid (PAA) performance that considers real-time changes in water quality. Artificial and recurrent neural networks (ANN and RNN, respectively) are trained to predict PAA at various locations throughout the disinfection basin, CT (a function of the active concentration and contact time), and pre- and postdisinfection Escherichia coli using online and laboratory data. An ANN is found to predict PAA concentrations at an error rate comparable to that of an online analyzer. Additionally, an ANN can predict CT more accurately than a conventional first-principles method both with and without an online analyzer. An ANN with a lagged response variable can predict E. coli in a fraction of the time of an RNN, but with a slightly increased error. The integration of the models developed in this work into existing monitoring and control systems could provide treatment facilities with more robust and dynamic disinfection control without the need for costly analyzers.
As an emerging oxidant and disinfectant, peracetic acid (PAA) has increasingly been used in wastewater treatment and the food and medical industries and has attracted greater research interest. To better understand reactions initiated by PAA, this paper is among the first to comprehensively review the reactivity of PAA with respect to organic compounds of various structures. The reactivities of PAA with respect to 123 organic compounds are compiled from the literature and new experiments, and possible reaction pathways and products are discussed. Overall, PAA is an electrophile with high selectivity in reaction. The second-order rate constants of PAA oxidation of organic compounds vary by nearly 10 orders of magnitude, from 3.2 × 10–6 to >1.0 × 10⁵ M–1 s–1, which are much larger than those of H2O2 coexisting in PAA solutions. Electron-donating groups of compounds increase the reactivity with respect to PAA, evidenced by the strong negative correlations between rate constants and substituent constants [Hammett (σ) or Taft (σ*)] of compounds. Sulfur moieties show exceptionally high reactivity with respect to PAA. Limited studies have shown that generally oxygen-added reaction products are formed from PAA oxidation. This critical review provides a useful foundation for advancing our understanding of the fate of organic compounds in wastewater treatment including PAA and identifies further research needs to evaluate a broader range of compounds and their oxidation products and toxicity.
Blooms of the cyanobacterium Microcystis aeruginosa are common in many eutrophic freshwater bodies and pose a serious threat to water quality, potentially giving rise to high turbidity, food web alterations, increased production of toxic microcystin (MC-LR) and odorous compounds. The comparative effectiveness of oxidant treatment of M. aeruginosa cells in culture media was evaluated by applying a mathematical model of chlorophyll-a (Chl-a), cells and MC removal. The oxidants were chlorine (1–5 mg∙L-1), hydrogen peroxide (HP: 50–150 mg∙L-1), percitric acid (PCA: 10–50 mg∙L-1), and peracetic acid (PAA: 1.5–7.5 mg∙L-1). The Weibull distribution model was applied to assess the degree of inactivation of M. aeruginosa viability under different oxidant treatments. First-order kinetics was successfully applied to the experimental data for Chl-a decay. Using the Weibull model, it was possible to predict the required exposure time (Tr) for oxidants to achieve a 99.9% reduction in viable M. aeruginosa cells with respect to the initial value. 5 mg∙L-1 chlorine produced a 81% degradation of [D-Leu1] MC-LR after 72 h, with an exposure time (Tr) of 141 h. Among the peroxide treatments (HP, PCA and PAA), PCA (10–50 mg∙L-1) produced the highest level of [D-Leu1] MC-LR degradation (39–79%), with low exposure times (Tr = 119–125 h). Chl-a concentration and M. aeruginosa counts for each oxidant treatment were highly correlated and successfully linked by a cubic polynomial. This is the first modelling report of M. aeruginosa decay by oxidant treatments.
Wastewater disinfection is important to protect human and ecosystem health. Peracetic acid (PAA) could be used as a disinfectant for wastewater and has the advantage of being less toxic to...
Chlorination and ozonation of various waters may be associated with the formation of toxic disinfection byproducts (DBPs) and cause health risks to humans. Monitoring the toxicity of chlorinated and ozonated water and identification of different toxicity mechanisms are therefore required. This study is one of its kind to examine the toxic effects of chlorinated and ozonated wastewater effluents on three genetically modified bioluminescent bacteria, in comparison to the naturally isolated cyanobacteria, Spirulina strains as test systems. Three different secondary wastewater effluents were collected from treatment plants, chlorinated using sodium hypochlorite (at 1 and 10 mg L-1 of chlorine) or treated using 3-4 mg L-1 of ozone at different contact times. As compared to cyanobacterial Spirulina sp., the genetically modified bacteria enhancing bioluminescence at the presence of stress agents demonstrated greater sensitivity to the toxicity induction and have also provided mechanism-specific responses associated with genotoxicity, cytotoxicity and reactive oxygen species (ROS) generation in wastewater effluents. Effects of effluent chlorination time and chlorine concentration revealed by means of bioluminescent bacteria suggest the formation of genotoxic and cytotoxic DBPs followed with their possible disappearance at longer times. Ozonation could degrade genotoxic compounds in some effluents, but the cytotoxic potential of wastewater effluents may certainly increase with ozonation time. No induction of ROS-related toxicity was detected in either chlorinated or ozonated wastewater effluents. UV absorbance- and fluorescence emission-based spectroscopic characteristics may be variously correlated with changes in genotoxicity in ozonated effluents, however, no associations were obtained in chlorinated wastewater effluents. The bacterial response to the developed mechanism-specific toxicity differs among wastewater effluents, reflecting variability in effluent compositions.
Peracetic acid (PAA) has been increasingly used by the poultry processing industry. However, information related to the potential PAA carryover to and effect on biological treatment processes, commonly used in poultry processing wastewater treatment, is limited. The objectives of this work were to assess the fate of PAA in poultry processing wastewater streams, investigate dominant factors contributing to PAA decomposition, and identify major PAA decomposition products. PAA was detected in chiller overflow and in the dissolved air flotation (DAF) unit influent and effluent only at the end of the processing shift. The PAA decomposition rate correlated positively with pH, temperature, wastewater strength and organic content, and negatively with initial PAA concentration. PAA decomposition followed one-step (pH ≥ 6) or two-step (pH < 6) pseudo-first order kinetics. Decomposed PAA in DAF effluent resulted in equimolar production of acetic acid. A decrease in DAF effluent COD was observed under high PAA doses.
Peracetic acid (PAA) is a potential alternative disinfectant for wastewater. While laboratory studies have shown promising results on PAA’s disinfection performance, knowledge gaps remain regarding scale-up and the potential additive effect of adding UV treatment after PAA treatment. A 4-week pilot study was conducted to investigate PAA disinfection of secondary and tertiary (granular media filtered) effluents. By varying PAA concentrations (2, 3, 4 and 6 mg l-1) and sampling location along the pilot reactor (theoretical contact times 2.2, 6.7 and 22.5 min), a wide range of C·t values 4.4 – 135 mg min l-1 was investigated. Additionally, a low-pressure UV lamp (30 mJ cm-2) was installed to determine if UV treatment augmented PAA disinfection. Disinfection performance was assessed based on the inactivation of three fecal indicator bacteria (FIB) (fecal coliforms, E. coli, and Enterococcus spp.) and a virus (somatic coliphage). PAA inactivation was greatest for fecal coliforms/E. coli, followed by Enterococcus spp., and then somatic coliphage. Results showed that increasing C·t resulted in an increase in the log reduction of FIB and coliphage in both secondary and tertiary effluents. The relative effectiveness of increasing PAA concentration versus contact time to improving inactivation varied among the microorganisms. Sequential PAA-UV treatment (PAA 45 – 135 mg min l-1, UV 30 mJ cm¬-2) achieved higher inactivation than PAA alone for somatic coliphage in secondary effluent, and for fecal coliforms, E. coli and somatic coliphage in tertiary effluent. PAA performance did not exhibit a dependence on any of the water quality parameters routinely monitored, including turbidity.
Peroxyacetic acid (PAA) is the most commonly used antimicrobial in spray bar antimicrobial treatment during fresh apple packing and processing. However, there are limited data regarding its practical efficacy against Listeria monocytogenes on fresh apples. This study evaluated the antimicrobial activity of PAA against L. monocytogenes on fresh apples applicable to current industry practice, and further examined practical parameters impacting its efficacy to maximize the biocidal effects. Apples were inoculated with a three-strain L. monocytogenes cocktail at ~6.0 Log10 CFU/apple and then subjected to comparative antimicrobial treatments after 48 h post-inoculation. An 80 ppm PAA treatment, at 30-s and 2-min exposure, reduced L. monocytogenes on fresh apples by ~1.3 or 1.7 Log10 CFU/apple, respectively. The anti-Listeria efficacy of PAA was not affected by the water hardness and pH of PAA solution, while it improved dramatically when applied at elevated temperature. A 2-min exposure of 80 ppm PAA at 43 and 46°C resulted in a 2.3 and 2.6 Log10 CFU/apple reduction, respectively. A 30-s contact time of 80 ppm PAA at 43-46°C reduced L. monocytogenes on apples by 2.2-2.4 Log10 CFU/apple. Similarly, PAA intervention at elevated temperatures significantly strengthened its effectiveness against naturally occurring apple microbiota. PAA treatment at 43-46°C can provide a vital method to improve antimicrobial efficacy against both L. monocytogenes and indigenous microbiota on fresh apples. Our data provide valuable information and reference points for the apple industry to further validate or verify process controls.
Fresh fruits and vegetables are a rich source of micronutrients. However, many foodborne illnesses have been linked to the consumption of fresh fruits and vegetables as they are reported to harbor contaminants such as microorganisms and pesticides. Recently reported foodborne outbreaks have been linked to a diverse group of fruits and vegetables due to the presence of various pathogens including Salmonella, Escherichia coli, and Listeria monocytogenes. Also, the increased use of pesticides has resulted in the deposition of chemical residues on the surface of fruits and vegetables, which has led to the adverse health conditions such as cancer, birth defects, and neurodevelopmental disorders. Fresh commodities are subjected to various treatments to prevent or minimize these outbreaks, and the main targets of such treatments have been the elimination of pathogens and degradation of toxic chemical residues. Here, we have discussed various decontamination methods including simple household washing, chemical treatments, and modern technologies with their mode of action for microbial and pesticide removal. The simple household processes are not very effective in the removal of pathogenic organisms and pesticides. The use of modern techniques like cold plasma, ozone, high hydrostatic pressure, and so on, showed better efficacy in the removal of microorganisms and pesticides. However, their industrial use is limited considering high installation and maintenance cost. In this review, we suggest combined methods based on their mode of decontamination and suitability for a selected fruit or vegetable for effective decontamination of microbes and pesticide together to reduce the treatment cost and enhance food safety.
The scarcity of natural resources supports the perspective of reusing treated effluents, mainly in agriculture, where the reduction in the demand of drinking water and the provision of alternative sources for nutrients are important. However, the process of disinfection, essential to the protection of human health, generates deleterious byproducts to both humans and the environment. This research aimed to evaluate the use of ozone as a disinfectant for wastewater treated by anaerobic/aerobic baffled reactor for later agricultural reuse. Disinfection tests were conducted by applying ozone, in batch, with applied dosages of 5, 8, and 10 mg.O3.L⁻¹ and contact time of 7 min. All the tests led to formaldehyde formation, therefore within the standard suggested by the World Health Organization. For the indicators total coliforms and Escherichia coli, the ozone was considered effective, satisfying the criteria for agricultural reuse according to the World Health Organization of a dosage of 8 mg.O3.L⁻¹.
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Chlorine is considered the most used chemical agent for water disinfection worldwide. However, water chlorination can lead to by-product generation which can be toxic to humans. The present study aimed to perform a systematic review on the toxicity of trihalomethanes (THMs) through bioindicators of cytotoxicity, genotoxicity, and mutagenicity. The results showed that studies on the effects of THMs on DNA are a current research concern for evaluating the toxicity of the pure compounds and real samples involving several types including water for recreational use, reused water, and drinking water. THMs deleterious effects have been assessed using several biosystems, where the Ames test along with experimental animal models were the most cited. A wide range of THM concentrations have been tested. Nevertheless, DNA damage was demonstrated, highlighting the potential human health risk. Among the studied THMs, chloroform presented a different action mechanism when compared with brominated THMs, with the former being cytotoxic while brominated THMs (bromodichloromethane, bromoform, and dibromochloromethane) were cytotoxic, genotoxic, and mutagenic. The described evidence in this research highlights the relevance of this topic as a human health issue. Nevertheless, research aimed to represent THMs current exposure conditions in a more accurate way would be needed to understand the real impact on human health.
Sodium hypochlorite (NaOCl) and peracetic acid (PAA) are being used for sanitization in food processing, but their chemical behaviors regarding disinfection byproducts (DBPs) formation during washing processes are still largely unknown. This study compared these two sanitizers in simulated washing processes for fresh-cut lettuce. Different doses of sanitizers were applied, and the wash water and washed lettuce were extracted and analyzed for 45 conventional and emerging DBPs of concern. Overall, washing by PAA generated much less DBPs than washing by NaOCl in both wash water and lettuce. Interestingly, the formation potentials of different groups of DBPs varied considerably in wash water versus in washed lettuce. This study is among the first to compare the two sanitizers for that many DBPs in both produce and wash water. The comprehensive data will facilitate the development of safer produce sanitization processes, and guide further research on DBPs in food.
Recent epidemiological studies conducted in Finland have reported a positive correlation between the mutagenicity of chlorinated drinking waters and certain human cancers. In these studies, past exposure to drinking water mutagenicity was assessed using a model developed by Vartiainen et al. [1] based on data collected in Finland. In this model, mutagenicity, as determined in the Ames assay, is a function of the total organic carbon (TOC) concentration of the water, chlorine dose, and to a minor extent, the concentration of ammonia. A study has been initiated to assess the applicability of this model to source waters and water treatment practices in the United States. Water samples were collected from three full-scale treatment plants and one pilot-scale plant. All the plants used chlorine exclusively for disinfection. One full-scale plant used ground water. Surface water sources were used by the other plants. TOC and ammonia concentrations were determined analytically and chlorine doses were obtained from the treatment plants. The water samples were concentrated by XAD resin adsorption for testing in the Ames assay. The observed levels of mutagenicity in the finished waters were 1.5 to 2-fold higher than those predicted using the model as specified in Vartiainen et al. [1]. Consequently, further validation is needed prior to widespread use of the Finnish model to assess exposure to mutagenicity in chlorinated drinking waters in the United States.
Epidemiologic evidence on the relation between contaminants in drinking water and cancer is reviewed. The reviewed studies cover exposure to: disinfection byproducts; nitrate; arsenic and other metals; volatiles and contaminants from hazardous waste sites; asbestiform fibers; radionuclides; and fluoride. Most investigations are ecologic, with some confirmation of elevated risk from individual-based studies. In the case of waterborne arsenic, and possibly chlorination byproducts, there is a consistent but small body of epidemiologic evidence of an association with one or more types of cancer. Nitrate in groundwater has increased greatly over the years, and the demonstration of endogenous nitrosation among highly exposed subjects raises concern of elevated cancer risk. However, the epidemiologic data are not yet sufficient to draw a conclusion. There is a diversity of studies among populations exposed to water contaminated with pesticides, volatile organics, or mixtures from hazardous waste sites. Studies of asbestiform fibers and radionuclides in water are not conclusive, but there are suggested elevations of several cancer sites in highly exposed populations. There is no suggestion that fluoride in drinking water is linked with elevated risk of cancer. As topics for epidemiologic evaluation, drinking water contaminants pose methodologic problems common to studies designed to detect relatively small elevations in risk, with the added challenge of assessing exposures for many years in the past. Nevertheless, epidemiologic assessment is valuable and clearly warranted, given the potential public health impact of small risk elevations among very large exposed populations, and the limitations of toxicologic experiments in assessing carcinogenic risk of complex mixtures or of compounds for which appropriate animal models are not available.
Drinking mutagenic downstream water from the Huangpu River was hypothesized to have increased the risk for male esophageal cancer in Shanghai, China. The authors conducted a population-based case-control study of a total of 71 esophageal cancer deaths and 1,122 controls collected during a 5-year follow-up period, 1984-1988, from four male cohorts born before January 1, 1944, living in four communities consuming water with different mutagenicities in the Shanghai area. The controls represented a 1% random sample of the defined living cohorts selected at the end of each of the 5 years of follow-up. Logistic regression showed an odds ratio of 2.77 (95% confidence interval: 1.52, 5.03) for drinking mutagenic downstream water from the river versus drinking nonmutagenic upstream water after controlling for possible confounders including age, disease history (hepatitis, cirrhosis, schistosomiasis, digestive tract ulcer), hazardous occupational history, pesticide exposure, lifestyle factors (cigarette smoking, tea intake, and alcohol intake), dietary habits (intake of pickled vegetables, maize, peanuts, and cured meat), education, poverty, urban environment, and water chlorination.
Laboratory experiments and full-scale trials in Brazil and Italy are reported that show that peracetic acid is a good disinfectant (better than sodium hypochlorite) of sewage in tropical and warm temperate climates. Its demonstrated effectiveness against V. cholerae suggests it should be a significant element in cholera control efforts.
The increasing use of products containing peracetic acid for the disinfection of sewage and effluents has produced a demand for information about the activity of PAA against relevant microorganisms. Studies have therefore taken place to establish the comparative effects of peracetic acid and chlorine on both bacteria and viruses. Peracetic acid has previously been shown to be active against faecal indicator bacteria. Recent laboratory studies have established that peracetic acid is also an effective agent against viruses typical of those found in sewage. This activity is maintained even in experimental systems containing high levels of organic matter such as yeast extract. In contrast, although sodium hypochlorite is an effective virucide in clean experimental systems, the presence of organic matter greatly increases the level of added available chlorine necessary to achieve a given level of viral inactivation.
Peracetic acid (PAA), a well known powerful antimicrobial agent in hospitals and in agribusiness (Fraser, 1986), has recently been used to disinfect urban effluents. It appears to be highly competitive against chlorine (Audic, 1990; Baldry, French, Slater and Desprez, 1990; Giodani, Iacoponi, Polidori, 1989), the most widely used disinfectant for sewage disposal.
As PAA is a new biocide, not much quantitative data is available on its action against the faecal indicator bacteria and viruses.
An on-site experimental study investigated the disinfectant action of PAA against these indicator bacteria and viruses as well as against Salmonella and enterovirus. To complete this study we will test its action on suspended solids to find out whether there is regrowth of the microorganisms after treatment.
Multi-factor analysis in terms of criteria like inactivation efficiency, safety environmental impact, and cost will be used to compare PAA to chlorination and ozonation, the most commonly used techniques.
Novel products based on peracetic acid (PAA) have recently been developed for the disinfection of sewage and sewage effluents. The efficacy of such products has been assessed under both laboratory and operational conditions.
Comparative laboratory studies of the effects of peracetic acid, chlorine dioxide and chlorine on indicator bacteria in secondary sewage effluent have shown peracetic acid to be a viable alternative to these halogen biocides.
In a trial carried out at two small rural works, PAA was dosed into secondary effluent from either an activated sludge plant or a percolating filter bed prior to tertiary lagoon treatment. LOW levels of PAA greatly enhanced the natural decline in coliform levels across the lagoon, enabling much lower concentrations of bacteria to be discharged into the receiving streams.
In another trial, secondary effluent from an activated sludge plant was treated before discharge into a stream leading to the sea. Coliform concentrations were greatly reduced along the watercourse downstream from the plant.
Laboratory experiments and full-scale trials in Brazil and Italy are reported that show that peracetic acid is a good disinfectant (better than sodium hypochlorite) of sewage in tropical and warm temperate climates. Its demonstrated effectiveness against V. cholerae suggests it should be a significant element in cholera control efforts.
Using a combination of mass spectrometry and infrared spectroscopy, disinfection byproducts were identified in ozonated drinking water containing elevated bromide levels and in ozonated water treated with secondary chlorine or chloramine. Only one brominated byproductdibromoacetonitrilewas found in the water treated with only ozone. This compound was found only in one of the three treatment rounds and was also present in the untreated, raw water but at levels 20 times lower than in the ozonated water. Many more byproducts were identified when secondary chlorine or chloramine was applied after ozonation. A number of these byproducts have not been reported previously. When comparing low-bromide water to water with elevated bromide, a tremendous shift in speciation was observed for samples treated with secondary chlorine or chloramine. Without high bromide levels, chlorinated species dominate (e.g., chloroform, trichloroacetaldehyde, tetrachloropropanone, dichloroacetonitrile, trichloronitromethane); with elevated bromide levels (1 mg/L), these shift to brominated species (e.g., bromoform, tribromoacetaldehyde, tetrabromopropanone, dibromoacetonitrile, tribromonitromethane). An entire family of bromo- and mixed chlorobromopropanones was identified that was not present in library databases and has not been reported previously. They were observed mainly in the ozone−chloramine samples but were also present in ozone−chlorine-treated water. These brominated byproducts were also observed in water treated with only chloramine or chlorine.
Using a combination of spectral identification techniquesgas chromatography coupled with low- and high-resolution electron-impact mass spectrometry (GC/EI-MS), low- and high-resolution chemical ionization mass spectrometry (GC/CI-MS), and infrared spectroscopy (GC/IR)we identified many drinking water disinfection byproducts (DBPs) formed by ozone and combinations of ozone with chlorine and chloramine. Many of these DBPs have not been previously reported. In addition to conventional XAD resin extraction, both pentafluorobenzylhydroxylamine (PFBHA) and methylation derivatizations were used to aid in identifying some of the more polar DBPs. Many of the byproducts identified were not present in spectral library databases. The vast majority of the ozone DBPs identified contained oxygen in their structures, with no halogenated DBPs observed except when chlorine or chloramine was applied as a secondary disinfectant. In comparing byproducts formed by secondary treatment of chlorine or chloramine, chloramine appeared to form the same types of halogenated DBPs as chlorine, but they were generally fewer in number and lower in concentration. Most of the halogenated DBPs that were formed by ozone−chlorine and ozone−chloramine treatments were also observed in samples treated with chlorine or chloramine only. A few DBPs, however, were formed at higher levels in the ozone−chlorine and ozone−chloramine samples, indicating that the combination of ozone and chlorine or chloramine is important in their formation. These DBPs included dichloroacetaldehyde and 1,1-dichloropropanone.
Although monochloramine has been considered as an alternative disinfectant to chlorine, little is known about the identity of the byproducts from its reaction with natural organics. In this study, byproducts in mutagenic extracts of monochloraminated aqueous fulvic acid were identified by high-resolution gas chromatography/mass spectrometry (HRGC/MS). These analyses resulted in the identification and quantification of the potent bacterial mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)furanone (MX), and the related compounds, (E)-2-chloro-3-(dichloromethyl)-4-oxobutenoic acid (EMX), (E)-2-chloro-3-(dichloromethyl)butenedioic acid (ox-EMX), and 2,3-dichloro-4-oxobutenoic acid (mucochloric acid). The compounds MX, EMX, and ox-EMX accounted for 9%, 26%, and 2%, respectively, of the mutagenic activity of the monochloramination extracts. Several short-chain (C2-C-9) aliphatic chlorinated organic acids, alcohols, and aldehydes were also identified. Of these, the alkenoic acids may be of toxicological significance because of their structural similarity to the open oxobutenoic form of MX.
Raw water and drinking water samples collected from five treatment plants supplied by a northern Italian lake in two periods of the year (summer and winter) were studied for their mutagenicity. The water samples were concentrated on silica C18 cartridges and the adsorbates were tested at increasing doses with a bacterial short-term mutagenicity test (Ames test with Salmonella typhimurium TA98 and TA100 strains), which reveals the gene-mutation-inducing ability of pollutants, and with a plant genotoxicity bioassay (Tradescantia/micronucleus test), which determines clastogenicity (chromosome-breaking ability). Raw water samples from all treatment plants were found to contain bacterial direct-acting mutagens detectable mainly with TA98 strain. The analyses of drinking water samples after water treatment showed some interesting results: TA98 mutagenicity was reduced when ozone was used together with chlorine dioxide, but TA100 mutagenicity was increased, though only in the summer sample; mutagenicity detectable with both strains was always reduced after chlorine dioxide disinfection; on the contrary, in all treatment plants using NaClO TA98 mutagenicity of winter samples increased. Raw lake water induced a high number of micronuclei in the Tradescantia/micronucleus test, showing a strong clastogenicity. This activity was higher in the NaClO-treated samples, and lower with the other disinfectants. Therefore, disinfection of lake water with ozone and/or chlorine dioxide seems to be a suitable alternative to the use of NaClO for controlling the formation of nonvolatile mutagens. The concentration method coupled with the two mutagenicity tests was found to be a simple, rapid and relatively inexpensive system for monitoring treatment plants and studying the influence of different disinfection systems on water mutagenicity.
This paper discusses the identification of organic disinfection byproducts (DBPs) at a pilot plant in Evansville, IN, which uses chlorine dioxide as a primary disinfectant. Unconventional multispectral identification techniques (gas chromatography combined with high- and low-resolution electron-impact mass spectrometry, low-resolution chemical ionization mass spectrometry, and Fourier transform infrared spectroscopy) were used to identify more than 40 DBPs in finished water at a chlorine dioxide pilot plant in Evansville, IN. Treatment variations included the use of liquid versus gaseous chlorine dioxide and the use of residual chlorine. Among the more unusual compounds identified were a:series of maleic anhydrides, which are believed to have been formed from maleic acids during the extraction and concentration process, and halopropanones.
A case-control study was done to assess a potential association between drinking water and pancreatic cancer in Washington County, Maryland. Cases of pancreatic cancer occurring from 1975 through 1989 were identified from the cancer registry. Controls were selected from the private 1975 census of Washington County. There were 101 cases and 206 controls. Chlorinated municipal water was used as a source of drinking water by 79% of cases and 63% of controls, yielding a significant odds ratio of 2.2. Adjustment for age and smoking had almost no effect on the risk, although both age and smoking were independently associated with an increased risk of pancreatic cancer. Although these findings must be interpreted with caution because of limitations in exposure assessment, these results have implications for the prevention of pancreatic cancer because chlorination of water is so widely practiced.
The mutagenic effects of the trihalomethanes (THMs: chloroform, CHCl3; dichlorobromomethane, CHCl2Br; dibromochloromethane, CHClBr2; bromoform, CHBr3), found in chlorinated drinking water have been studied for their ability to induce chromosome aberrations (CA) in vivo in rat bone marrow cells. THMs were administered intraperitoneally (i.p. acute) and orally (subacute). Using a maximal dose of 1 mmole/kg body weight, positive results were noted for CHCl3, CHCl2Br, CHClBr2 and CHBr3 with i.p. treatment, and for CHCl3 and CHBr3 with oral treatment. The time-dependent increase in CA showed a maximum level at 12 h after i.p. injection and at 18 h after the fifth and last day of oral treatment.
The information summarized in this review provides substantial evidence for the widespread presence of genotoxins in drinking water. In many, if not most cases, the genotoxic activity can be directly attributed to the chlorination stage of drinking water treatment. The genotoxic activity appears to originate primarily from reactions of chlorine with humic substances in the source waters. Genotoxic activity in drinking water concentrates has been most frequently demonstrated using bacterial mutagenicity tests but results with mammalian cell assay systems are generally consistent with the findings from the bacterial assays. There is currently no evidence for genotoxic damage following in vivo exposures to animals. In some locations genotoxic contaminants of probable industrial and/or agricultural origin occur in the source waters and contribute substantially to the genotoxic activity of finished drinking waters.
3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) was found to be a direct-acting mutagen in the Ames test for strains TA1535, TA1538, TA92, TA97, TA98, TA100 and TA102. The highest mutagenic response (approximately 13,000 revertants/nmol) was seen in strain TA100. The TA100 response was six- to tenfold higher than in TA98, TA97, and TA102, and 100- to 500-fold higher than in TA1535, TA92, and TA1538. The addition of a 9,000 x g supernatant fraction (S-9) from livers of polychlorinated biphenyl-treated rats, along with cofactors for NADPH generation, resulted in a 90% reduction in the TA100 mutagenicity. MX induced chromosomal aberrations in Chinese hamster ovary cells after 6-8 hr exposure without S-9 at a dose as low as 4 micrograms/ml, and after 2 hr exposure with S-9 at a dose of 75 micrograms/ml. The oral dose of MX lethal to 50% (LD50) in Swiss-Webster mice was determined to be 128 mg/kg. MX did not induce micronuclei in mouse bone marrow when administered by oral gavage at doses up to 70% of the LD50.
In this study, three qualitatively different raw water supplies together with their correspondent chlorinated drinking waters were investigated for their mutagenic properties using the Salmonella/microsome assay. A drinking water supply distributed through two different types of pipelines was chosen in order to study the effect of the distribution systems on water mutagenicity. A sequential liquid-liquid extraction at three different pHs and an in situ XAD-2 adsorption technique were used to prepare extracts and adsorbates from both untreated and treated water samples to compare mutagen recovery by these widely used methods and with a view to selecting a routine screening technique for evaluating the effect of treatments on drinking water mutagenicity.
The Allium test is suggested as a standard in environmental monitoring, e. g. as a part of a test battery. Background, the method including suggested parameters for standard use, results from various application areas and comparisons with a number of other test systems are presented. The Allium test is a short-term test with many advantages: low cost, ease to handle, good chromosome conditions for the study of chromosome damage or disturbance of cell division including the evaluation of risks of aneuploidy. The ability of the root cells to activate promutagens (the MFO-system) further widens the application areas of the Allium test. The use of series of onions for each concentration of the test chemical allows statistical considerations, and from growth curves Effect-Concentration values are obtained. The Allium test is, lastly, a sensitive test showing good correlation to other test systems. Thus, positive results in the Allium test should be considered as a warning and also an indication that the tested chemical may be a risk to human health and to our environment.
The methods for detecting carcinogens and mutagens with the Salmonella mutagenicity test were described previously (Ames et al., 1975b). The present paper is a revision of the methods. Two new tester strains, a frameshift strain (TA97) and a strain carrying an ochre mutation on a multicopy plasmid (TA102), are added to the standard tester set. TA97 replaces TA1537. TA1535 and TA1538 are removed from the recommended set but can be retained at the option of the investigator. TA98 and TA100 are retained. We discuss other special purpose strains and present some minor changes in procedure, principally in the growth, storage, and preservation of the tester strains. Two substitutions are made in diagnostic mutagens to eliminate MNNG and 9-aminoacridine. Some test modifications are discussed.
Four coded chemicals, azidoglycerol (AG), N-methyl-N-nitrosourea (MNU), sodium azide (NaN3), and maleic hydrazide (MH), were tested with the Tradescantia micronucleus (Trad-MCN) bioassay by five independent laboratories from five different countries. The purpose of this international collaborative study was to evaluate four plant bioassays, of which the Trad-MCN assay was one, for their sensitivity, efficiency and reliability. The study was carried out under the sponsorship of the International Programme on Chemical Safety. All laboratories adhered to a standard Trad-MCN protocol which suggested that three replicate tests be conducted with each chemical. The results reported by all laboratories, although not equal, showed good agreement among the laboratories. In fact, all five laboratories obtained positive results with MH and MNU, while four of the five laboratories achieved positive results with NaN3. AG was tested in only three laboratories. Two reported negative results, while one reported positive results but only at a single high dose. The data from this study suggest that under normal conditions, the Trad-MCN bioassay is an efficient and reliable short-term bioassay for clastogens. It is suitable for the rapid screening of chemicals, and also is specially qualified for in situ monitoring of ambient pollutants.
The acid, mutagenic compounds present in chlorinated drinking water have caused concern about the potential cancer risk of drinking-water mutagenicity. In this study, past exposure to drinking water mutagenicity was assessed for the years 1955 and 1970 in 56 Finnish municipalities, using the historical information on water quality and treatment. Cases of leukemia, lymphomas, and cancers of the liver, pancreas, and soft tissue were derived from the Finnish Cancer Registry for two periods: 1966-1976 and 1977-1989. Relative risk was estimated in an additive Poisson regression model, adjusting for age, gender, social class, urbanity, and time period. In an ordinary municipality that was supplied with mutagenic drinking water (3,000 net rev/l), the observed exposure-response relationship indicated a relative risk of 1.1-1.3 for lymphomas and 1.1-1.2 for pancreatic cancer, compared with municipalities in which nonmutagenic drinking water was consumed.
The assessment of past exposure is a prerequisite to all epidemiological studies on drinking water and cancer. In this study the past exposure assessment of drinking water carcinogenicity was done in terms of the drinking water mutagenicity estimated from historical water parameters and compared with the methods used previously in past exposure assessments in studies on drinking water and cancer. The method was applied in 56 municipalities in Finland. The comparison of different methods in past exposure assessment suggests some advantages for the method presented as it allows a quantitative exposure assessment based on historical information on drinking water mutagenicity. Nevertheless the relevance of the method is with respect to the role of mutagenicity in carcinogenicity and the water type in question.
Any and all chemicals generated by human activity can and will find their way into water supplies. The types and quantities of carcinogens present in drinking water at the point of consumption will differ depending on whether they result from contamination of the source water, arise as a consequence of treatment processes, or enter as the water is conveyed to the user. Source-water contaminants of concern include arsenic, asbestos, radon, agricultural chemicals, and hazardous waste. Of these, the strongest evidence for a cancer risk involves arsenic, which is linked to cancers of the liver, lung, bladder, and kidney. The use of chlorine for water treatment to reduce the risk of infectious disease may account for a substantial portion of the cancer risk associated with drinking water. The by-products of chlorination are associated with increased risk of bladder and rectal cancer, possibly accounting for 5000 cases of bladder cancer and 8000 cases of rectal cancer per year in the United States. Fluoridation of water has received great scrutiny but appears to pose little or no cancer risk. Further research is needed to identify and quantify risks posed by contaminants from drinking-water distribution pipes, linings, joints, and fixtures and by biologically active micropollutants, such as microbial agents. We need more cost-effective methods for monitoring drinking-water quality and further research on interventions to minimize cancer risks from drinking water.
This review discusses the relation between by-products of drinking water chlorination and cancer in the light of present toxicological and epidemiologic evidence. During the chlorination of drinking water, a complex mixture of by-products forms from chlorine and the organic and inorganic compounds present in raw water. The quality and quantity of such compounds depend on the specific nature of the organic material in raw waters, the inorganic material in raw water, pH, temperature, other water treatment practices, and the chlorine timing and dose added. Chlorination by-products are important mainly when surface water is used for drinking water as more organic compounds are present in surface waters than in ground waters. The gastrointestinal and urinary tract are the cancer sites that are most often associated with the use of chlorinated surface water or with the quantity of chlorination by-products in the water-supply network. Yet the microbial quality of drinking water should not be compromised by excessive caution over the potential long-term effects of disinfection by-products because the risk of illness and death resulting from exposure to pathogens in untreated drinking water may be several orders of magnitude greater than the cancer risks from chlorination by-products.
Three short-term assays (SOS chromotest, Ames fluctuation test and newt micronucleus test) were performed to detect the genotoxic
activity of organohalides, compounds likely to be found in chlorinated and/or ozonated drinking water: monochloro-, dichloro-
and trichloroacetic acids and monobromo-, dibromo- and tribromoacetic acids. With the SOS chromotest, only three of the chemicals
studied (dichloroacetic acid, dibromo- and tribromoacetic acids) were found to induce primary DNA damage in Escherichia coli PQ 37. In the Ames fluctuation test, all the compounds except monochloroacetic acid showed mutagenic activity in Salmonella typhimurium strain TA100. In these two in vitro tests, a good correlation between increasing number of substituents and decreasing mutagenicity was observed. Namely, the
toxicity of brominated and chlorinated acetic acids decreased when the number of substituents increased. The newt micronucleus
test detected a weak clastogenic effect on the peripheral blood erythrocytes of Pleurodeles waltl larvae for trichloroacetic acid only.
Seven water samples collected from Vienna and Salzburg areas in Austria were tested for their clastogenicity with the Tradescantia-micronucleus (Trad-MCN) assay. There was no indication of clastogenic activity in two drinking water samples; likewise, samples from two major rivers (Danube and Salzburg) and of a river that received effluents from a paper mill also gave negative results. Urban river water as well as ground water samples which were collected near an industrial waste dump site caused a statistically significant and dose dependent increase of the MCN frequencies.
Haloacetic acids are by-products of drinking water disinfection. Several compounds in this class are genotoxic and have been identified as rodent hepatocarcinogens. Enzymes produced by the normal intestinal bacteria can transform some promutagens and procarcinogens to their biologically active forms. The present study was designed to investigate the influence of the cecal microbiota on the mutagenicity of haloacetic acids, and to look at changes in the microbiota populations and enzyme activities associated with exposure to haloacetic acids. PYG medium containing 1 mg/ml of monochloroacetic (MCA), monobromoacetic (MBA), dichloroacetic (DCA), dibromoacetic (DBA), trichloroacetic (TCA), tribromoacetic (TBA), or bromochloroacetic (BCA) acid was inoculated with rat cecal homogenate and incubated anaerobically at 37 degrees C. Growth curves were performed with enumeration of the microflora populations on selective media. Mutagenicity in a Salmonella microsuspension bioassay was determined after incubation for various lengths of time, with or without the cecal microbiota. At 15 h of incubation, enzyme assays determined the activities for beta-glucuronidase, beta-galactosidase, beta-glucosidase, azoreductase, nitroreductase, dechlorinase, and dehydrochlorinase. The haloacetic acids, with the exception of BCA, were toxic to the cecal microbiota, and especially to the enterococci. DBA, TBA, and BCA were mutagenic in the microsuspension assay, but the presence of the intestinal flora did not significantly alter the mutagenicity. BCA increased the activities of several enzymes, and therefore has the potential to affect the biotransformation of co-exposed compounds.
Organic reaction products of chlorine dioxide and natural aquatic fulvic acids Water Chlorination, Environ-mental Impact and Health Effects
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- Jd Johnson
- Rf Christman
- Millington
- Rl Jolley
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Colclough CA, Johnson JD, Christman RF, Millington DS. 1983. Organic reaction products of chlorine dioxide and natural aquatic fulvic acids. In Jolley RL, Brungs WA, Cotruvo JA, Cumming RB, Mattice JS, Jacobs VA, eds, Water Chlorination, Environ-mental Impact and Health Effects, Vol 4. Ann Arbor Sciences, Ann Arbor, MI, USA, pp 219–229
Ozone disinfection by-products: Optimization of PFBHA derivatization method for the analysis of aldehydes
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Sclimenti MJ, Krasner SW, Glaze WH, Weinberg HS. 1990. Ozone disinfection by-products: Optimization of PFBHA deriv-atization method for the analysis of aldehydes. Proceedings, American Water Works Association Water Quality Technology Conference, American Water Works Association, San Diego, CA, November 11–15, pp 477–501.
Mutagens in the aquatic environ-ment
- S Monarca
- Pasquini
Monarca S, Pasquini R. 1989. Mutagens in the aquatic environ-ment. In Cheremisinoff PN, ed, Encyclopedia of Environmental Control Technology, Vol 3. Gulf Publishing, Houston, TX, USA, pp 139–170.
Mutagenic and clasto-genic properties of 3-chloro-4
- Meier Jr
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Meier JR, Blazak WF, Knohl RB. 1987. Mutagenic and clasto-genic properties of 3-chloro-4-(
Health effects of disinfectants and disinfection by-products. American Water Works Association Re-search Foundation
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- Kopfler
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Bull RJ, Kopfler FC. 1991. Health effects of disinfectants and disinfection by-products. American Water Works Association Re-search Foundation, Denver, CO.
Identification and occurrence of ozonation by-products in drinking water. American Water Works Association Research Foundation
- Glaze Wh
- Weinberg
Glaze WH, Weinberg HS. 1993. Identification and occurrence of ozonation by-products in drinking water. American Water Works Association Research Foundation, Denver, CO.
Ozone disinfection by-products: Optimization of PFBHA derivatization method for the analysis of aldehydes
- Glazewh Sclimentimj Krasnersw
- Weinberghs