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Alkylphenol ethoxylates and alkylphenols - update information on occurrence, fate and toxicity in aquatic environment

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Alkylphenols and their precursors, alkylphenol etoxylates, are a group of manmade chemicals used mainly as surfactants in domestic and industrial applications worldwide. It has been well established that they have endocrine disruption activity, hepatotoxic, genotoxic and other negative effects on animal and human health. In spite of the effort to reduce their use, they persist in the environment not only in industrial but also in remote regions, and were detected in the variety of natural matrices including air, water, soil as well as food products, and human blood and urine worldwide. This article summarizes their occurrence, fate in natural conditions, and toxicity including mode of action. A subject of our concern was the aquatic environment as the most important reservoir and target of their deleterious impact.
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DOI 10.2478/pjvs-2013-0111
Review
Alkylphenol ethoxylates and alkylphenols
update information on occurrence,
fate and toxicity in aquatic environment
J. Kovarova
1
, J. Blahova
1
, L. Divisova
1
, Z. Svobodova
1
1
Department of Veterinary Public Health and Animal Welfare, Faculty of Veterinary Hygiene and Ecology,
University of Veterinary and Pharmaceutical Sciences Brno,
Palackeho tr. 1/3, 612 42 Brno, Czech Republic
Abstract
Alkylphenols and their precursors, alkylphenol etoxylates, are a group of manmade chemicals
used mainly as surfactants in domestic and industrial applications worldwide. It has been well estab-
lished that they have endocrine disruption activity, hepatotoxic, genotoxic and other negative effects
on animal and human health. In spite of the effort to reduce their use, they persist in the environment
not only in industrial but also in remote regions, and were detected in the variety of natural matrices
including air, water, soil as well as food products, and human blood and urine worldwide. This article
summarizes their occurrence, fate in natural conditions, and toxicity including mode of action. A sub-
ject of our concern was the aquatic environment as the most important reservoir and target of their
deleterious impact.
Key words:Nonylphenol, octylphenol, wastewater, xenoestrogen, fish, vitellogenin
Abbreviationsand units
AhR aryl hydrocarbon receptor
AP alkylphenol
APE alkylphenol ethoxylates
EDC endocrine disrupting chemicals
EO ethoxylate portmon
ER oestrogen receptor
NP nonylphenol
OP octylphenol
STP sewage treatment plants
WWTP wastewater treatment plant
Correspondence to: J. Blahova, email: blahovaj@vfu.cz, tel.: +420 541 562 785
Introduction
Alkylphenol ethoxylates (APE) are one of the
most widely used classes of surfactants. Recently, ap-
proximately 500,000 tons have been produced world-
wide annually (Renner 1997) and it makes APEs the
world’s third largest group of surfactants in terms of
production and use (Ying et al. 2002). They can be
used as detergents, wetting agents, dispersants, emul-
sifiers, solubilizers and foaming agents. APEs are im-
portant to a number of industrial applications, includ-
ing pulp and paper, textiles, coatings, agricultural pes-
Polish Journal of Veterinary Sciences Vol. 16, No. 4 (2013), 763–772
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R
OOOH
R
OOO
mOH
R
OOOH
m-1
OOH
R
O
OOH
R
OH
R
Alkylphenol polyethoxylate
(APnEO,n=m+1)
m
R = C H , nonyl
C H , octyl
R is usually branched
919
817
Alkylphenoxycarboxylic acid
(ApnEC)
Alkyphenol polyethoxylate
AP(n - 1)EO
Progressive shortening
of ethoxylate chain
Alkylphenoxyacetic acid
(AP 1 EC) Alkylphenol monoethoxylate
(AP 1 EO)
Alkylphenol (AP)
Ring cleavage, oxidation of alkyl chain
Fig. 1 Degradation pathway of alkylphenolethoxylate (Renner 1997).
ticides, lube oils and fuels, metals and plastics. Indus-
trial applications comprise 55% of the APE market.
The remaining uses include industrial and institu-
tional cleaning products (30%), household cleaning
products (15%) and other miscellaneous uses (<1%).
APEs are surfactants manufactured by reaction of al-
kylphenols (AP) with ethylene oxide. APE molecule
consists of two parts AP is fairly non-polar portion
which allows to dissolve grease and other materials
that have small water solubility, and the ethoxylate
portion (EO) of the surfactant is water-soluble and
aids in the transfer of material to the aqueous phase.
This structure makes most of polar APEs soluble in
water and helps disperse dirt and grease from soiled
surfaces into water (Snyder et al. 2001).
APs, in addition to their role as a raw material for
APEs, are used in the preparation of phenolic resins,
polymers, heat stabilizers, antioxidants and curing
agents. From this group of chemicals, nonylphenol
(NP) is by far the most commercially important AP in
Europe, with an annual production of about 75,000
tons, 60% of which is used to make NPEs (RPA
1999). Moreover, NP as well as octylphenol (OP) and
AP mono- to triethoxylates (APE1, APE2 and APE3)
are more persistent and more toxic metabolites gener-
ated by degradation of APEs. These metabolites are
ubiquitous in the environment because of widespread
use of APEs surfactants and widespread lack of ad-
equate wastewater treatment, and these compounds
have been detected in air, water, sediment, soil and
biota at different levels in different parts of the world
(Giger et al. 1984).
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Occurrence in environment
APEs and their degradation products are not pro-
duced naturally. Their presence in the environment is
solely a consequence of anthropogenic activity. Due
to their exceptional nature they can be considered as
amphophilic compounds. Lower APE oligomers (EO
<5) are usually described as water-insoluble or
lipophilic, whereas higher oligomers are described as
water-soluble and hydrophilic (Ahel and Giger 1993,
Jonsson et al. 2008). Another very important feature
of these chemicals is their ability to bind with organic
matter because of their very low partition coefficient
(log Kow for APEs metabolites between 3.90 and
4.48) (Ying et al. 2002). Therefore, APEs and/or their
metabolites were determined in whole range of
abiotic and biotic matrices all over the world. As men-
tioned above, APEs are readily biodegraded under
both aerobic and anaerobic conditions in the environ-
ment (Paasivirta and Rantio 1991) including microbial
degradation, losing most of EO units; the final break-
down products are APEs with one or two EO (APE1,
APE2), alkylphenoxy carboxylic acid, and APs
(Fig. 1). Many studies assessing levels of APEs and
their emerging metabolites have been published in re-
cent years and have shown the ubiquitous distribution
of these chemicals in sewage treatment plant dis-
charges, sediments and live organisms.
Occurence in wastewater discharges
This partial biodegradation was observed in a ma-
jority of sewage treatment plants (STP) during sewage
treatment processes that makes from sewage treatment
plant effluents and wastewater discharges an important
source of this type of compounds (David et al. 2009).
The efficiency of wastewater treatment plants
(WWTPs) in removal of NP was found to be highly
variable ranging from 11% to 99% depending on type
of treatment process unit employed (Berryman et al.
2004). A treatment process composed of ozonation and
subsequent activated carbon filtration with chlorination
was the most effective (removal of 95% of NP) (Pet-
rovic et al. 2003). If contaminants are adsorbed on ac-
tivated sludge particles, they accumulate in the
WWTPs sludge. In this case, the application of diges-
ted sludge, as fertilizer, on agricultural fields may cause
a potential contamination of soil and ground water
(Olea et al. 1996). Concentrations of ΣAPE meta-
bolites in treated wastewater effluents, for example in
the US, ranged from <0.1 to 369 μg/L (Rudel et al.
1998), in Spain they were between 6 and 343 μg/L (Sole
et al. 2000) and concentrations up to 330 μg/L were
foundintheUK(BlackburnandWaldock1995).
Occurrence in water
Many communities worldwide, such as Europe,
use surface or groundwater resources for drinking
water production, which contain a significant portion
of wastewater effluent (Sonnenschein and Soto 1998).
In some drinking wells these chemicals were detected
at concentrations ranging from <limit of detection to
32.9 μg/L (Rudel et al. 1998). To date, the amount of
APs pollution detected in aquatic environments most-
ly ranges from nanograms to milligrams per litre
(Uguz et al. 2003). Same data were presented also by
Naylor et al. (1992), who reported that water concen-
tration of NP seldom overwhelms 10 μg/L, though at
some “hot spots” concentrations reach 1000 μg/L
(Warhurst 1995).
In groundwater samples APs concentrations were
usually higher than those found in surface water. The
removalofcontaminantsisinfactveryslowinground-
water since chemical and biological characteristics in
the aquifers are not favourable for degradation pro-
cess. Groundwater temperatures are in the psych-
rophilic range and both carbon sources and oxygen
are limited. Microbiological resources of such ecosys-
tems are restricted and contaminants undergo ex-
tremely slow degradation process allowing con-
taminants to disperse up to several kilometers from
the contamination source and to exist for decades
(Soares et al. 2008).
In surface water the amount of this type of pollu-
tants is lower (Arditsoglou and Voutsa 2008). In Asia,
NP concentrations were found within the range of 0.3
to 2.8 μg/L (Basheer et al. 2004). Nevertheless, even
these numbers exceed environmental quality stan-
dards established by EU authorities to achieve the
good surface water quality status. The environmental
quality standards, as annual average concentration,
for NP and OP in surface water were proposed to 0.3
μg/L and 0.1 μg/L, respectively, however, environ-
mental quality standards are still not harmonised
throughout the EU (European Commission 2006).
Furthermore, these environmentally realistic concen-
trations of NP may have toxic effect on aquatic fauna
(Ying et al. 2002). Interestingly, APs contamination in
surface water shows seasonal variations. NP and OP
concentrations were observed higher in the warmer
season than in the colder part of year (Tsuda et al.
2000, Isobe et al. 2001). It was suggested that a micro-
bial activity at warmer temperatures leads to an en-
hanced degradation of NPE and OPE (Li et al. 2004)
as well as photolysis induced by sunlight can influence
the concentration of APs in the surface layer of natu-
ral waters during summer (Ahel et al. 1994). Just as
temperature and light availability also salinity was de-
termined as a factor influencing the presence of APs
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in the water (Li et al. 2005). Sampling locality choice
influenced measured concentrations in a very import-
ant manner. A shallow part of continental shelf, along
the coast, is the most sensitive due to smaller volume
of water and proximity of point and diffuse sources of
wastewater discharge or other specific source of APs
pollution such as produced water. The produced
water is a by-product of current oil-production tech-
nology and consists of seawater containing an ex-
tremely complex mixture of dispersed oil, polycyclic
aromatic hydrocarbons, APs, organic acids, metals
and traces of production chemicals (Meier et al.
2011). In contrast, in deep sea areas concentrations
decrease rapidly as the distance from the coast in-
creases (Xie et al. 2006). Measurements of APs con-
tent in water column have obvious shortcomings
caused by the unfavourable physicochemical charac-
teristics. The environmental distribution is estimated
to 25% in water, more than 60% in sediments, more
than 10% in soil (Nordic Council of Ministers 1996).
Occurrence in water sediments
In the aquatic environment AP was found at high-
er concentrations in associations with sediments
rather than dissolved in the aqueous phase. Although,
organic content of the sediments was one of the im-
portant determinants of adsorption process. In sedi-
ments free of organic matter, adsorption was also ob-
served indicating that not only organic content is rel-
evant for NP. It was chased up that NP adsorption is
controlled by two major interactions: hydrophilic in-
teraction with mineral components and hydrophobic
interaction with organic matter (John et al. 2000). NP
concentrations of up to 20,700 ng/g were found in
sediments sampled near a sewage outlet in Tokyo Bay
(Kurihara et al. 2007). NP was also found at high
levels (13700 ng/g) in sediment in Jamaica Bay (USA)
impacted by sewage inputs (Fergusson et al. 2001).
Remarkably, in a study of Kelly et al. (2010) chemical
analysis of representative site samples of the Shannon
International River Basin District in Ireland also
identified APs in water and sediments in mg/L and
mg/kg concentrations, respectively. In sediments there
was determined another interesting phenomenon like
the vertical distribution of APEs and APs. It could be
influenced by many factors as vertical transport by
pore water diffusion or physical and/or bio mixing.
Peng et al. (2007) found a decline in NP concentra-
tions in the layer dated to the end of 1980s, corre-
sponding to the onset of wastewater treatment,
whereas the recorded increase in the NP concentra-
tion in the layer dated to 1990s could be explained by
the increased economic growth and the lack of effi-
cient wastewater facilities. Sediments are the main
medium, where persistent organic pollutants with
some lipophilic nature can be stored. For the NP
a risk of release from sediment has been evaluated
and it was concluded that, due to an unfavourable
ratio of sizes of the hydrophilic and hydrophobic parts
of the molecule, NP is not subject to micelle forma-
tion. Thus, NP is not expected to be able to mobilize,
e.g., hydrophobic pollutants as PAHs (Brix et al.
2001). In accordance with this findings the estimation
of APs half-lives was provided. Ekelund et al. (1993)
reported the half-lives of NP based on ultimate biode-
gradation of about 58 days in seawater and 35 days in
aerobic seawater plus sediment at 11
o
C while Shang et
al. (1999) reported NP’s half-life in sediments more
than 60 years.
Occurrence in biological matrices
The accumulation tendency of these group of sub-
stances is evident not only in inorganics but also in the
biological matrices, particularly aquatic biota (Ahel et
al. 1994). However, in a study presented by Arukwe et
al. (2000) it was suggested that NP does not accumu-
late in tissues and that a half-life of NP in the tissues
of the rainbow trout (Oncorhynchus mykiss) is about
24-48 hours. Based on many other studies it was con-
cluded that APs are able to accumulate in several
aquatic species, including aquatic plants, algae, fish
and mussels (Liber et al. 1999, Lintelman et al. 2003).
In fish, the highest concentration of APs was found in
the fat of exposed organisms (Shiraishi et al. 1989)
and it was reported that NP bioaccumulates up to
410-fold in fish (Tsuda et al. 2000, Snyder et al. 2001).
High accumulation potential was also determined for
oysters and snails that both serve as transport media
and potential sources of APs in marine environment
(Cheng et al. 2006). It was also noted that an ability of
marine organisms to accumulate APs depends on
their feeding strategy. A higher proportion of APs was
found in organisms with the highest exposure to sedi-
ments (e.g. filter feeding organisms) and so APs con-
centrations in marine organisms were higher in be-
nthic and pelagic organisms that live close to the sedi-
ment than in fish (David et al. 2009). These findings
revealed that the main source of APs for marine or-
ganisms is not water column and intake through gills
but sediments and dietary uptake, both depending on
the AP distribution in the aquatic environment. On
the other hand, uptake through skin and gills was also
demonstrated (Ferreira-Leach and Hill 2001). A dis-
tribution of APs in live organisms was also inves-
tigated and, due to partly lipophilic nature of APs,
their target tissues in fish (such as the adipose tissue,
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brain, liver, kidney, muscle, skin and eye) are rich in
grease (Ferreira-Leach and Hill 2001). The study, us-
ing radio-labelled compounds demonstrating their
distribution, indicates that the liver and bile are
a main excretion route for absorbed APs, and the con-
centration of AP metabolites excreted in bile in-
creased with increasing degree of alkylation. It should
be emphasized that uptake, metabolism and elimin-
ation of xenobiotics, including APs, vary with com-
pound, exposure route and fish species (Tollefsen and
Nilsen 2008). The muscle tissue of the chub (Leucis-
cus cephalus) in the Czech Republic contains
1.92-6.11 ng/g w.w. of ΣNP + OP (Zlabek et al. 2006).
Some fish species from Adriatic Sea, Italy, have NP
levels from 12 to 1,431 ng/g w.w. and OP levels of
0.3-4.7 ng/g w.w. (Ferrera et al. 2005). Basheer et al.
(2004) presented concentrations of NP about 60.5
ng/g w.w. and OP about 31.4 ng/g w.w. in fish in Sin-
gapore. Fish in the UK were found to contain up to
0.8 ng/g w.w. of NP in the muscle tissue (Ying et al.
2002), whereas geometrical mean of NP in snails and
oysters was calculated in range of 380-1,560 ng/g and
92-1,080 ng/g d.w., respectively. Bioconcentration fac-
tors for oysters and snails exceed those in fish (Cheng
et al. 2006). Reported bioconcentration factor of NP
in whole fish ranged from 280 to 1,300
(Ferreira-Leach and Hill 2001). As mentioned above
the highest values of APs were determined in fish bile,
because glucuronic acid conjugates are the main ex-
cretion form of APs. In the study of Jonsson et al.
(2008) the levels of OP reached 579 ng/g and NP 19
ng/g of fish bile in the North Sea. The levels of NP
detected in fish bile in the UK reached 195-2,453
ng/mL and, in fish exposed to wastewater discharge,
values were even up to 12,678 ng/mL (Fenlon et al.
2010). It could be concluded that variability in APs
accumulation in water organisms is affected by feed-
ing habits, metabolism, levels of contamination in the
individual habitats, biotransformation and excreting
capacity.
Toxicity and risk factors
An increasing concern for APs occurrence in the
environment was initiated by investigations of
feminized male fish found near sewage outlets in sev-
eral rivers all over the world; a mixture of chemicals
containing APs that results from degradation of deter-
gents during sewage treatment seemed to be a causal
agent of this endocrine disruption (Purdom et al.
1994, Auriol et al. 2006). Even though suspicion of
toxicity of APs was declared in 1938 by Dodds and
Lawson (1938) and confirmed by Soto et al. (1991),
the aim to restrict the use of this group of chemicals
was accomplished in Europe in 2001 by their inclusion
in the list of priority hazardous substances for surface
waters (European Commission 2000) and in the USA
by developing “chronic criteria recommendations” for
NP by US EPA (2005). This procedure is in accord-
ance with the fact that the majority of chemicals that
have been in production before 1981 has not been
subjected to the present requirements for the environ-
mental evaluation of new chemicals (Wallstrom 2004).
Therefore, only 3% of 2,500 high-volume chemicals
currently in use are well-tested, including their
long-term effects (Soares et al. 2008). Intensive re-
search focused on mode of action as well as other
toxicologic potential of these compounds was started
since the ability of NP, OP and APE1, APE2 and
APE3, present in the environment at sufficient levels,
to mimic natural hormones and disrupt endocrine
function was demonstrated (Tabata et al. 2001). Be-
sides the main detrimental xenoestrogenic effect,
these compounds were confirmed as potential car-
cinogens (Pedersen et al. 1999, Uguz et al. 2003),
hepatotoxins (Meier et al. 2007), genotoxins (Hwang
et al. 2010) and behavioural modulators affecting
basic survival reflexes such as locomotors activity or
aggression (Xia et al. 2010). On the molecular basis,
APs have been reported to bind to oestrogen recep-
tors (ER) of both fish and mammals (Gutendorf and
Westendorf 2001, Tollefsen 2002) and activate estro-
gen-responsive element regulating reporter genes
(Kuiper et al. 1998, Legler et al. 1999). They are ca-
pable to interfere with steroid hormone receptor ac-
tivity (Kudo and Yamaguchi 2005), steroid metab-
olism (Arukwe et al. 1997) and plasma endogenous
steroids in aquatic animals (Tollefsen 2007), too. It
indicates that this group of pollutants acts through
multiple mechanisms to cause potentially endocrine
disruption.
In general, the endocrine and reproductive effects
of chemicals are believed to exist due to their ability
to: (1) mimic the effect of endogenous hormones, (2)
antagonize the effect of endogenous hormones, (3)
disrupt the synthesis and metabolism of endogenous
hormones, and (4) disrupt the synthesis and metab-
olism of hormone receptors (Sonnenschein and Soto
1998). APs have been shown to cover more than two
of these effects. Very interesting outcomes that some
of the APs displayed apparent antagonistic activity at
low micromolar concentration whereas acting as weak
estrogens at high concentrations were presented by
Silva et al. (2002). Thus APs and alkylated non-phen-
olics act as both agonistic and antagonistic estrogens
depending on concentration. Antiandrogenic activity
through affecting aromatase activity and a function of
the aryl hydrocarbon receptor (AhR) was also con-
firmed by Bonefeld-Jogensen et al. (2007). It follows
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that, except to “classical” oestrogen receptors, APs
are able to bind to the AhR, which regulates some
ER-responsive genes (Safe and Gaido 1998); the
pregnant X receptor, which may regulate endogenous
steroid metabolism (Masuyama et al. 2000), the nic-
otinic receptor, where NP directly modulates ion cur-
rent (Nakazawa and Ohno 2001) and even cAMP re-
sponsive element as a key signalling route of many
hormones and substances (Cheshenko et al. 2008).
Some APs also induced significantly a p53 gene ex-
pression, as demonstrated in copepod, indicating the
involvement of p53 in such stress-responses (Hwang
et al. 2010). Recently, Yang et al. (2006) also assumed
that p53 gene would be closely related to the impacts
of endocrine disrupting chemicals (EDCs) on ecosys-
tem biota and human health. They were also deter-
mined as potent inhibitors of Ca
2+
-ATPase disrupting
Ca
2+
homeostasis in fish, perhaps contributing to cell
and tissue damage during key stages in the develop-
ment and thereby influencing normal endocrine func-
tion later in life (Kirk et al. 2003). A recently dis-
covered neuropeptide, kisspeptin, crucially important
substance for the triggering of puberty and for future
fertility in mammals (Oakley et al. 2009), and similar
function in teleost of fish (Katashi et al. 2009) is sus-
pected to be affected by APs, too.
It has been reported that NP exerts its biochemi-
cal effects by down regulating an activity of micro-
somal cytochrome P4501A while stimulating an in-
crease in the cytochrome P4503A protein in the liver
of mammals and fish (Uguz et al. 2003). It was shown
that 220 μg/L of NP induce neoplastic proliferation of
reticuloendothelial cells in fish hepatopancreas after
2 weeks and an increase in glutathione S-transferase
activity after 1 week and replacement of the normal
liver parenchyma by the fibrous tissue after 4 weeks
(Arukwe et al. 2000). Thus, it could be assumed that
NP has also the ability to cause variations in isoforms
of hepatic cytochrome P450-dependent steroid and
xenobiotic metabolizing enzymes (Servos 1999). Final-
ly, not all APs are able to disrupt the reproductive
function in a live body. Interesting observations per-
taining to structure-function relationships were made:
(i) the alkyl chain must have at least 3 carbons, (ii)
only the p-isomers are estrogenic, (iii) polyalkylated,
hindered phenols like butylated hydroxytoluene and
Irganox 1640 (Ciba-Geigy) are not estrogenic while
they are effective antioxidants, and (iv) fused rings
like naphthols are not estrogenic in spite of being an
integral part of the A and B ring of natural steroids
(Sonnenschein and Soto 1998). The estrogenicity is
dependent on ligand-binding affinity, transcriptional
and post-transcriptional regulation of ER-dependent
genes, and the toxicokinetics of the compound (Beres-
ford et al. 2000, Katzenellenbogen et al. 2000).
Since the toxicity potential of APs was deter-
mined, monitoring strategies to assess these com-
pounds and their biological impact in the environment
have been developed. As endocrine disrupting chemi-
cals they can affect a number of reproductive par-
ameters in fish, including gonadal development
(Meier et al. 2007), induction of plasma vitellogenin
in male and juvenile fish (Jobling and Sumpter 1993),
inhibition of spermatogenesis (Jobling and Sumpter
1993) and oogenesis (Weber et al. 2003), all of them
could be used as markers of endocrine disruption. The
hepatic induction of vitellogenin production in male
and juvenile oviparous fish, which occurs normally
only in maturing females under stimulation of 17β-es-
tradiol, has been proposed as a sensitive biomarker of
the exposure to estrogenic chemicals of endogenous
and exogenous origin (Sumpter and Jobling 1995,
Randak et al. 2009). Interestingly, the calculated con-
tribution of the anticipated NP and OP to the poten-
tial estrogenicity of discharge from healthcare facili-
ties was found greater than 65% of the total potential
estrogenicity (Nagarnaik et al. 2010). Healthcare facil-
ities like hospitals, nursing facilities, assisted living fa-
cilities, and independent living facilities, were suspec-
ted of releasing immense amount of natural or syn-
thetic hormone metabolites and of responsibility for
endocrine disruption. According to the study of
Nagarnaik et al. (2010) their share of endocrine dis-
ruption is based more on releasing of APs that have
weaker estrogenic effectsthan hormones but the APs
are released in higher amounts. APs were present in
part per billion concentrations in water samples taken
near healthcare facilities compared to the
part-per-trillion concentrations of hormones. An in-
tensive use of detergents in healthcare facilities and
industry could be more important source of NPs in
the environment because NPE based detergents enter
the municipal system and enhance their participation
in endocrine disruption in the aquatic ecosystem. Fi-
nally, levels in the environment that are capable to
induce reproduction impairment were determined.
The acute toxicity with 96hLC50 calculated for NP
has been determined for at least 22 different species
of fish with reported 96hLC50s ranging from 17 to
3,000 μg/L, although most of the values ranges from
100 to 300 μg/L (Gray and Metcalfe 1997, Dwyer et al.
1999). Chronic toxicity values (NOEC) are as low as
6μg/L in fish and 3.7 μg/L in invertebrates (Servos
1999) and LOEC was at nominal dose of 4 μg/kg body
weight of AP for the effects of timing of puberty, and
20 μg/kg body weight of AP for the delay effect in
mature fish (Meier et al. 2011). Likewise, Bellingham
et al. (2010) demonstrated that developing foetus is
sensitive to environmentally relevant concentrations
of EDCs that may have serious impact on the future
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development of the reproductive system. The body
burden corresponds to water exposure in the ng/L
concentration range and this is 100times lower than
the APs concentrations (μg/L) that have previously
been reported to induce vitellogenin in male or juven-
ile fish and have been documented in surface water all
over the world (Meier et al. 2011). Further indicators
of EDCs toxicity could be sex steroid-binding protein
determination (Tollefsen and Nilsen 2007) or behav-
ioural changes assessment (Xia et al. 2010). It was
demonstrated that APs and alkylated non-phenolics
are able to bind successfully to the rainbow trout sex
steroid-binding protein. Unfortunately, the most ubi-
quitous AP like NP was not proved to bind to rainbow
trout sex steroid-binding protein (Tollefsen and Niel-
sen 2007). On the other hand, measurements of sev-
eral behavioural endpoints, especially locomotors ac-
tivity, aggression displays and group preference, may
provide an effective assessment of NP in the aquatic
ecosystem but this measurement has some limitations
like biotic and abiotic factors in field conditions
(Spence et al. 2008, Xia et al. 2010). Other studies are
needed to establish more sensitive and specific
markers of APs detrimental activity but, as well
documented, chemicals exist as complex mixtures in
the environment and groups of compounds may cause
mixed toxicity even though each compound is present
below its threshold for effect (Silva et al. 2002).
Conclusions
Recently provided information demonstrated seri-
ous damaging impact of EDCs on aquatic organisms,
in particular. Besides natural/synthetic hormones,
PCBs, dioxins, some insecticides and bisphenol-A,
APs and APEs constitute very potent EDCs as well as
persistent substances with multiple toxicity, deleteri-
ous effect and bioaccumulative features. In spite of
the fact that their use was reduced in Europe, USA
and Japan in last few years, they are still very popular
in some other countries and contamination of the en-
vironment with these chemicals is of substantial con-
cern in the whole world. Not only sex in reversal fish
(Sumpter 1998), but also altered social and reproduc-
tive behaviour in birds (Fox 2001), impaired penile
development in alligators (Guillette et al. 1999),
cryptorchidism and infertility in the Florida panther
(Facemire et al. 1995) are virtual consequences of an
increase in EDCs in the environment. These findings
have implications for the study of human conditions
that are suspected to be caused by environmental es-
trogens, such as undescended testis, breast cancer and
a decrease in sperm counts and quality during last 50
years (Wolf et al. 1993). Furthermore, APs have ap-
peared to be able to interfere with the regulatory sys-
tems of different types of cells by several mechanisms
and thus are not compounds of single harmful effect.
It is an alarming finding that NP is ubiquitous in food-
stuffs at concentrations ranging from 0.1 to 19.4 μg/kg
with an estimated daily intake of 7.5 μg/day for an
adult (Guenther et al. 2002). The ubiquity of this type
of pollutants in the environment supports a need for
greater knowledge of APs bioaccumulation process
and their human or animal health alteration potential.
Options of waste water treatment process improve-
ment and/or also APs/APEs possible substitution in
the industrial use with another type of substances are
still animated issues for further investigation.
Acknowledgements
We thank MVDr. Veronika Simova for manu-
script improvement and English correction.
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... Alkylphenol ethoxylates (APEOs) are non-ionic surfactants widely applied to industrial products, such as pulp and paper, textiles, coatings, agricultural pesticides, lube oils, fuels, metals, and plastics, and about 60% of APEOs are discharged into the aquatic environment [5,6]. APEOs consist of a hydrophobic carbon chain and an ethylene oxide chain of 1-50 units, but typical products generally contain 9-10 units [7,8]. ...
... µg/kg [19]. NPEO [3][4][5][6][7][8][9][10][11][12][13] and OPEO [3][4][5][6][7][8][9][10][11][12][13] in beehive matrices (honey, pollen, and wax) were measured, with recoveries from 75 to 111% [20]. ...
... µg/kg [19]. NPEO [3][4][5][6][7][8][9][10][11][12][13] and OPEO [3][4][5][6][7][8][9][10][11][12][13] in beehive matrices (honey, pollen, and wax) were measured, with recoveries from 75 to 111% [20]. ...
Article
Full-text available
Alkylphenol ethoxylates (APEOs) represent a non-ionic surfactant widely used as adjuvants in pesticide formulation, which is considered to cause an endocrine-disrupting effect. In the current study, we established a detection method for the APEOs residue in tea based on solid-phase extraction (SPE) for the simultaneous analysis of nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) by UPLC-MS/MS. In the spiked concentrations from 0.024 to 125.38 μg/kg for 36 monomers of APEOs (nEO = 3-20), the recoveries of APEOs range from 70.3-110.7% with RSD ≤ 16.9%, except for OPEO20 (61.8%) and NPEO20 (62.9%). The LOQs of OPEOs and NPEOs are 0.024-6.27 and 0.16-5.01 μg/kg, respectively. OPEOs and NPEOs are detected in 50 marketed tea samples with a total concentration of 0.057-12.94 and 0.30-215.89 µg/kg, respectively. The detection rate and the range of the monomers of NPEOs are generally higher than those of OPEOs. The current study provides a theoretical basis for the rational use of APEOs as adjuvants in commercial pesticide production.
... Alkylphenols are used as precursors in the production of nonionic surfactant APEOs, which are then used as or in various products, including lubricating oil additives, phenol resins and antioxidants for rubber and plastics. Due to the intensive use of APEOs, they are frequently detected in effluents from WWTPs, and in surface waters, sediments and biota (Acir and Guenther, 2018;Kovarova et al., 2013). Chlorination of alkylphenols occurs in both WWTPs and drinking water treatment plants. ...
... Octylphenol and nonylphenol have been detected in various human tissues and body fluids (Acir and Guenther, 2018;Kovarova et al., 2013). The most frequently found alkylphenol in human tissues was nonylphenol, as it is more commonly used than octylphenol. ...
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The everyday use of household and personal care products (HPCPs) generates an enormous amount of chemicals, of which several groups warrant additional attention, including: (i) parabens, which are widely used as preservatives; (ii) bisphenols, which are used in the manufacture of plastics; (iii) UV filters, which are essential components of many cosmetic products; and (iv) alkylphenol ethoxylates, which are used extensively as non-ionic surfactants. These chemicals are released continuously into the environment, thus contaminating soil, water, plants and animals. Wastewater treatment and water disinfection procedures can convert these chemicals into halogenated transformation products, which end up in the environment and pose a potential threat to humans and wildlife. Indeed, while certain parent HPCP ingredients have been confirmed as endocrine disruptors, less is known about the endocrine activities of their halogenated derivatives. The aim of this review is first to examine the sources and occurrence of halogenated transformation products in the environment, and second to compare their endocrine-disrupting properties to those of their parent compounds (i.e., parabens, bisphenols, UV filters, alkylphenol ethoxylates). Albeit previous reports have focused individually on selected classes of such substances, none have considered the problem of their halogenated transformation products. This review therefore summarizes the available research on these halogenated compounds, highlights the potential exposure pathways, and underlines the existing knowledge gaps within their toxicological profiles.
... Örneğin, su kütlelerine boşaltılan bazı deterjanların içeriklerinde alkil fenol etoksilat bulunmakta ve bunlar balıklarda cinsel anormalliklere neden olmaktadır. 24 Balıklarda, özellikle teleostlarda sudan maruziyet sonrası farklı endokrin değişiklik raporlanmasına rağmen az sayıda çalışma EBK'lere maruz kalmanın bir sonucu olarak popülasyon düzeyinde sonuçlar ortaya koymaktadır. 25 Amfibiyanlar su evresindeyken, özellikle ksenobiyotik maruziyetlerine karşı hassastırlar. ...
... Nonylphenol (NP) and octylphenol (OP) are persistent and highly lipophilic biodegradation products of polyethoxylated alkylphenol surfactants, widely used in production of detergents, lubricants, emulsifiers, pesticide formulations, paints and personal use products (Bila and Dezotti, 2007). They are known estrogenic, toxic and carcinogenic endocrine disruptors (Kovarova et al., 2013). The potential risks associated with the presence of hormones and environmental estrogens made them the focus of many of the water quality monitoring studies reported in Table 1, although there are still no guidelines or regulations that establish discharge limits for these substances in Brazil. ...
... The levels of NP depended on the size of NP discharges into the river, temperature, flow velocity, biodegradation, etc. About 60% of NP and its derivatives produced in the world ends up in water supply [98][99][100]. In addition, the presence of NP is observed in polyvinyl chloride (PVC), which can contaminate water passing through PVC plumbing [101]. ...
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Environmental pollution with organic substances has become one of the world’s major problems. Although pollutants occur in the environment at concentrations ranging from nanograms to micrograms per liter, they can have a detrimental effect on species inhabiting aquatic environments. Endocrine disrupting compounds (EDCs) are a particularly dangerous group because they have estrogenic activity. Among EDCs, the alkylphenols commonly used in households deserve attention, from where they go to sewage treatment plants, and then to water reservoirs. New methods of wastewater treatment and removal of high concentrations of xenoestrogens from the aquatic environment are still being searched for. One promising approach is bioremediation, which uses living organisms such as fungi, bacteria, and plants to produce enzymes capable of breaking down organic pollutants. These enzymes include laccase, produced by white rot fungi. The ability of laccase to directly oxidize phenols and other aromatic compounds has become the focus of attention of researchers from around the world. Recent studies show the enormous potential of laccase application in processes such as detoxification and biodegradation of pollutants in natural and industrial wastes.
... It was also observed that the stabilization capability may be improved by the presence of additional polar groups, notably OH, in the aromatic ring (Tyman, 1979). However, it has been well established that alkylphenol have endocrine disruption activity, hepatotoxic, genotoxic and other negative effects on animal and human health (Servos 1999, Kovarova et al. 2013, Acir et al. 2018. Additionally, alkylphenols (typically nonylphenol), are very stable, persistent, and hydrophobic, which leads to its accumulation in sewerages and rivers and their volatilization into ambient air. ...
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Phenolic resins are major class of polymeric compounds used for treating asphaltene instability related challenges. Such compounds often act like as artificial resins naturally present in crudes to prevent the aggregation of asphaltene molecules and therefore their tendency to deposit on solid surfaces. However, these phenolic resins are known to have toxicity and biodegradability issues. Aim of this work is to elucidate and compare cardanol ethoxylates derivatives as asphaltene dispersants in comparison with commonly used phenolic resins chemistries. To characterize the effects of cardanol chemistries, a series of laboratory tests were conducted. The thermo-electric properties of the crude oils were studied both with and without chemical treatments to establish state of asphaltenes and their disaggregation. Optical dispersion testing confirmed whether cardanol formulations affected the sedimentation rate and particle size distribution of flocculated asphaltenes within the oil matrix. An Asphaltene Dynamic Deposition Loop (ADDL) test verified the effectiveness of the cardanol ethoxylates on the overall asphaltene deposition rate under flow conditions. Finally, the rheology and viscoelastic properties of the treated oil were examined at various temperatures and shear rates with specific focus on steady state and low shear environments. Results were compared against commercially available resin-based products. In a thermodynamically stable crude oil medium, the asphaltene molecules exist in an equilibrium state and contributes least towards the overall thermo-electric reading of the test sample. Addition of an effective asphaltene inhibitor disrupts this equilibrium and disperses the polar asphaltene molecules within the crude matrix, leading to higher thermo-electric values. For the crude samples tested, it was observed that the addition of cardanol derivatives increased the thermo-electric response thus improving the asphaltene dispersion. Further validation of this improvement was confirmed with the optical dispersion test results. Relative to the blank or untreated sample, adding formulations with cardanol ethoxylates resulted in lower sedimentation rate and settling velocity of the heavy asphaltene fraction. Furthermore, effectiveness of cardanol as a surface-active agent that can avert the preferential sticking of the polar asphaltene fraction onto the metal surface of production and transportation flowlines was also assessed using the ADDL test. Lastly, the low-shear rheological analyses of the treated and untreated crude samples also corroborate synergistic efficiency of cardanol containing formulations to decrease the bulk sample viscosity. Cardanol ethoxylates belong to a class of surfactants derived from renewable and sustainable raw materials that can be considered as a viable option for upstream oilfield applications. Results from this study are quite encouraging and could set the stage for development of new asphaltene inhibitors and improve our capability to control asphaltene flocculation in more complex fluids and production systems including high asphaltenic crudes.
... Indeed, a study conducted on sewage sludge in Turkey revealed the significant differences in the presence of NPs between the summer and the winter seasons (Ömeroglu et al., 2015). The removal rates of NP and OP were related to the treatment process of WWTPs (Kovarova et al., 2013). In addition, it was indicated that NPs were formed during the treatment process due to a precursor compound (Loos et al., 2013). ...
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Increase in the contamination of the aquatic environments is a global challenge; hence, understanding the sources of priority substances (PSs) is essential. In an attempt to implement this principle, a year-long monitoring covering all seasons was carried out in the influents and effluents of four largest wastewater treatment plants (WWTPs) in Istanbul. Results obtained showed the presence of 48 PSs (66% of the target compounds) including pesticides, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), dioxins and dioxin-like compounds (DLCs), alkylphenols, phthalates, and metals ranging from low nanograms to micrograms per liter. Priority hazardous substances that were banned for long were still found to be present in wastewaters. PAHs, DLCs, alkylphenols, and metals were found to be present in all samples. Di(2-ethylhexyl) phthalate (DEHP) and DLCs were detected in more than 80% of the influent samples. Trichloromethane had the highest concentrations among the most frequently (80–100%) detected PSs in the influents and effluents. The potential risks that may arise from WWTP effluents containing PSs were estimated by calculating the risk quotients (RQs). Upon the risk estimation conducted on the PSs in effluents, monitoring of the endrin, alpha-cypermethrin, theta-cypermethrin, zeta-cypermethrin, quinoxyfen, bifenox, benzo-ghi-perylene, and DEHP is recommended for the WWTP effluents. Graphical Abstract
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The study presents a simple and non-laborious method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs), 2 phthalate esters (PEs), 2 alkylphenols (APs) and 4 alkylphenol ethoxylates (APEOs) in sediment. The method employs sample preparation combining focused ultrasound solid–liquid extraction (FUSLE) and in situ clean-up followed by liquid chromatography with fluorescence and ultraviolet detection. Extraction of 0.5 g sediment samples with 7 mL acetone in the presence of activated silica (0.5 g) and powdered copper (0.2 g) using an ultrasonic probe for 1 min resulted in recoveries of target analytes ≥ 78 %. The analytical method was classified as “acceptable green analysis” by the analytical Eco-Scale assessment (AESA) and scored 0.54 in the AGREEprep greenness assessment for sample preparation. Matrix-matched calibration was used to quantify analytes with a linear range for PAHs 2–1000 ng g–1, for PEs 100–5000 ng g–1 and for APs and APEOs 40–2000 ng g–1 dry weight. The reached limits of quantification (LOQ) for PAHs ranged from 1.1 to 3.1 ng g􀀀 1, for PEs from 122 to 124 ng g􀀀 1, for APs from 40 to 51 ng g􀀀 1 and for APEOs from 36 to 53 ng g􀀀 1. The applicability of the method was demonstrated by the analysis of real sediment samples and natural matrix certified reference material.
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The pollution of the oceans with plastic and other anthropogenic litter is alarming, as is evidenced by an abundance of research on marine debris. In contrast, terrestrial anthropogenic litter and its impacts are largely lacking scientific attention. Therefore, the main objective of the present study is to find out whether the litter burden is as severe in terrestrial flora and fauna as it is in the ocean. For this purpose, five meadows and the gastric content of 100 slaughtered cattle as well as 50 slaughtered sheep have been examined for persistent man-made debris in Northern Bavaria, Germany (49°18’N, 10°24’E). All of the five meadows contained garbage, and plastics were always part of it. 521 persistent anthropogenic objects were detected altogether in a total survey area of 139050 m², equalling a litter density of 37.5 items per hectare (3747 items/km²). The litter spectrum included 245 plastic items (17.6 items/ha = 1762 items/km²), with a significantly higher abundance in meadows which were either adjacent to waste dumps or frequently used by pedestrians. The plastic abundance was only, though not significantly, surpassed by glass with 263 items (18.9 items/ha = 1891 items/km²) and significantly underrun by metal with 13 pieces (0.9 items/ha = 93 items/km²). 92.7 % of all the meadow-litter were fragments, 73.3 % represented packaging material, and 75.5 % had documented equivalents in marine debris. Of the 100 examined cattle, 30 animals harboured anthropogenic foreign bodies in their gastric tract, reaching a total amount of 82 items, with a mean of 0.8 ± 2.5 items per animal. Among the 50 examined sheep, 3 animals (6.0 %) contained a total of 9 anthropogenic items with a mean of 0.2 ± 0.8 objects per sheep. Plastics were the most dominant litter material, encompassing 68.3 % of the man-made objects in the bovine and 100 % in the ovine gastric tracts. Fibres were the most frequent plastic litter type, with a share of 71.4 % of the bovine and 44.4 % of the ovine plastic foreign bodies. Glass, ceramic and metallic objects have also been detected, but only in cattle. 93.9 % of the bovine and 100 % of the ovine anthropogenic foreign bodies were fragments. Two young cows (2.0 %) showed traumatic lesions in the reticulum associated with long pointed metal items, a nail in one cow and two wire fragments in the second one. In three other cattle (3.0 %), metal wires were accompanied by punctual tongue lesions. In the rumen of two other cattle (2.0 %), bezoars had conglomerated around plastic fibres. Stones in the abomasum, mainly in the company of sand, were related to abomasitis geosedimentosa in 9 cattle (9.0 %). In one sheep (2.0 %), a necrotic spot on the ruminal mucosa coincided with the presence of 5 rubber-balloon fragments in the ruminal content. Altogether 68.2 % of the anthropogenic objects in the bovine and ovine gastric tracts could be traced back to agricultural equipment, mainly wrapping materials from silage, straw or hay bales, while 28.6 % of the foreign bodies originated in common end-consumer products. 26.4 % of the anthropogenic litter items ingested by the studied farm ruminants had direct equivalents in the studied meadows, 30.8 % in the debris of marine environments and 29.7 % in the gastrointestinal foreign bodies of marine animals. At least in this study region, waste pollution affected terrestrial environments and domestic animals, with clear equivalents in the marine world. Ingested foreign bodies produced lesions that may have reduced the animal’s welfare and, regarding commercial purposes, their productivity.
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A review of the available information on the toxicity and bioaccumulation of alkyphenols (AP) and their polyethoxylates (APE) and polyethoxycarboxylates (APEC) was conducted in support of their assessment as Priority Substances under the Canadian Environmental Protection Act. This included an examination of the acute and chronic toxicity of these compounds in a wide variety of aquatic organisms as well as an examination of their potential effects on endocrine function in fish and aquatic invertebrates. Although the data in the literature are scattered among many species, different test methods and chemicals, there is a consistent pattern in the toxicity. Nonylphenol (NP) and octylphenol (OP) are both acutely toxic to fish (17-3000 μg/L), invertebrates (20-3000 μg/L) and algae (27-2500 μg/L). In chronic toxicity tests no observable effect concentrations (NOEC) are as low as 6 mg/L in fish and 3.7 μg/L in invertebrates. There is an increase in the toxicity of both NPEs and OPEs with decreasing EO chain length. NPECs and OPECs are less toxic than corresponding APEs and have acute toxicities similar to APEs with 6-9 EO units. APs and APEs bind to the estrogen receptor resulting in the expression of several responses both in vitro and in vivo, including the induction of vitellogenin. The threshold for vitellogenin induction in fish is 10 μg/L for NP and 3 μg/L for OP. APEs also affect the growth of testes, alter normal steroid metabolism, disrupt smoltification and cause intersex (ova-testes) in fish. The available literature suggests that the ability of AP and APEs to bioaccumulate in aquatic biota in the environment is low to moderate. BCFs and BAFs in biota, including algae, plant, invertebrates and fish range from 0.9 to 3400. Although there are relatively few data available for OP or OPEs, their potential to bioaccumulate is expected to be similar to that of corresponding NP and NPEs.
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There is now unequivocal evidence that a wide variety of chemicals capable of disrupting the endocrine system are present in the aquatic environment. These range from natural (e.g. 17β-oestradiol) and synthetic (e.g. ethinyl oestradiol) oestrogens through to industrial chemicals that can mimic endogenous hormones (e.g. nonylphenol, some pesticides). Relatively little is known about the fate and behaviour of these chemicals in the aquatic environment, and hence it is unclear which organisms are exposed to the chemicals, and to what degree. This makes predicting possible effects difficult. Nevertheless, enough examples, such as the masculinisation of female molluscs exposed to the anti-fouling agent TBT (tributyltin), and the feminisation of male fish exposed to oestrogenic chemicals in effluent from sewage-treatment works, are documented to demonstrate that adverse affects are occurring. The challenge now is to assess how wide-ranging these adverse effects are, to determine their severity at the population level, and to gauge how serious an issue endocrine disruption is compared to other factors (such as habitat loss) which are also adversely impacting aquatic organisms.
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