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Lead uptake from sea water and food, and lead loss in the common mussel Mytilus edulis
Abstract
Common mussels, Mytilus edulis (shell length 19 to 21 mm, average dry weight 30 mg) were maintained for 6 weeks in sea water containing different concentrations of lead (0.005 to 5 mg l-1). The lead concentration in the mussels' whole soft parts was analysed at different times during the experiment. A constant rate of lead uptake, linearly dependent on the lead concentration of the medium, was observed. Thus, the temporal change of the concentration factor is also linear (regression coefficient 149.9 daily). Rate of lead loss, measured after transferring the mussels into natural sea water, is linearly dependent on the original lead concentration in the soft parts. Rates of uptake and loss in large mussels (shell length 45 to 55 mm, average dry weight 750 mg) are less than those in small mussels (shell length 19 to 21 mm, average dry weight 30 mg). During a much more extended experimental period, adjustment to a steady state is expected to occur; rates of lead uptake and loss are then non-linear. Lead uptake by individual organs (kidney, gills, adductor muscle, digestive gland, foot, mantle with gonads) of large M. edulis (shell length 45 to 55 mm, average dry weight 750 mg) was analysed in 2 test series. In the test series medium, the mussels were kept in a seawater medium containing 0.01 mg. Pb.l-1. In the test series food, the mussels were kept in natural sea water but fed with the green algae Dunaliella marina containing lead (approximately 600 g.g-1 dry weight). The lead quantity given per mussel per day was about 2 g in both test series. Within 35 days, the mussels of test series medium took up 29% of the total amount of lead given, those of test series food took up 23.5%. In all organs, lead concentration increased, but rates of uptake differed; the kidney displayed by far the highest rate of uptake. With these physiological properties M. edulis is an ideal indicator organism for lead pollution in the marine environment. A biologic calibration curve, the relationship between lead concentration in the mussels' whole soft parts at equilibrium and lead concentration in sea water, is presented.
... Moreover, there does not seem to be any equilibrium between radioactive Cd 109 and stable Cd already accumulated in the mussel. Schulz-Baldes [51] reported extensive studies of lead uptake by Mytilus edulis and suggested a relationship between the concentration of lead in mussel tissues and the average concentration of lead in the surrounding water. The uptake of iron might be expected to be unusual since this metal normally occurs in sea water as a colloidal precipitate of hydrated ferric hydroxide [52] and yet readily accumulates to high concentrations in the common mussel Mytilus edulis [53]. ...
... Mussels (Mytilus spp.) are recognized as sentinels of heavy element marine and freshwater pollutions since their metal concentrations reflect the water concentrations in which they live [53,51,67]. Since they are living organisms, metal uptake and accumulation may also affected by a number of intrinsic and extrinsic factors [68,69]. ...
... Other studies revealed that the body size might change the heavy metal uptake due to the changes in the kinetic steady-states as mussels grew [68]. Schulz-Baldes [51] found a similar effect for the uptake of lead by Mytilus edulis: again, uptake was faster in smaller animals than in larger ones. Obviously, body size would affect metal bioaccumulation in the rates of uptake and excretion [81]. ...
The oceans and seas with high population density are submitted to numerous anthropogenic
pressures: among them, the chemical pollution by heavy metals. These pollutants, coming
from our continental activities, are transported through rivers or by air and accumulate in
seas and oceans where they mainly affect coastal areas. During the 70ies, scientist suggested
to use organisms, in particular mussels of the genus Mytilus, as bioindicator, in order to
evaluate the status of chemical contamination of coastal ecosystems. Mussels like the genus
Mytilus are widely considered as one of the most suitable sentinels and biological indicators
of pollution since they possess a multitude of useful characteristics for this purpose: sessile
filter feeders that accumulate contaminants in their tissues; exhibit low ability to metabolize
organic contaminants; have stable local populations in many places; and have a wide array of sensitive biomarker tools available. The heavy metal concentrations in the Mytilus spp. reflect the coastal water concentrations in which they live. Since they living organisms,
metal uptake and bioaccumulation may also affected by a number of biotic and abiotic
factors such as: body size, location within the intertidal zone, the time of collection, the
temperature, the salinity, and the pH. These influences must be identified and measured, so that they may be taken into account during sampling, validation of results, or in the
interpretation of monitoring data. We concluded that Mytilus spp. was a sensitive
bioindicator for monitoring of the past and the present coastal pollution by heavy metals.
Therefore provides a global view of the health status of the coastal environment.
... For instance, we found some significant effect of pH on Pb CFs in mussel soft tissues (Fig. 2B) after 9 days of exposure but, a longer-term exposure under these two environment stressors would provide additional information on how and when quasi-equilibrium is attained and about the relationship between Pb bioconcentration at steady state and surrounding pH T (Boisson et al., 1998;Boudjenoun et al., 2007;Metian et al., 2009). Information is available on Pb depuration and organ-and cell-specific detoxification processes in bivalves under normocapnia conditions (Boudjenoun et al., 2007;Metian et al., 2009;Regoli and Orlando, 1994;Schulz-Baldes, 1974); however, much more information is required to better assess the influence of pH on these processes. ...
Changes in seawater pH can alter the chemical speciation of waterborne chemical elements, affecting their bioavailability and, consequently, their bioaccumulation in marine organisms. Here, controlled environmental conditions and a 210 Pb radiotracer were used to assess the effect of five distinct pH conditions (pH T ranging from 7.16 to 7.94) on the short-term (9 days) accumulation of Pb in the blue mussel, Mytilus edulis. After 9 days of exposure, higher levels of Pb were observed in the soft tissues of mussels maintained in the lower pH conditions, while Pb levels accumulated by mussel shells showed no difference across pH conditions. These results suggest that pH decreases such as those predicted by ocean acidification scenarios could enhance Pb contamination in marine organisms, with potential subsequent contamination and effect risks for human consumers.
... 1 Heavy use of lead in gasoline, batteries and pigments since the 20th century has led to an increased risk of human exposure to lead from various sources, including plants and seafood that absorb lead from contaminated soil 2 and waterways. 3 Upon entering the bloodstream, lead is excreted in bile and urine. Remaining lead binds to red blood cells, distributes throughout soft tissues and finally accumulates in the bones. ...
A rhodamine-based fluorescent lead probe reports on the labile lead pool within cells.
... In the case of lead, the gonad is the most targeted organ, such that its distribution in the tissues analyzed indicates that the highest concentration is reached in the gonads; the second order of accumulation is in the gills, which has been reported by various authors [54,56,57] to be a detoxifying organ. ...
The phosphate fertilizer and phosphoric acid industries increase phosphogypsum levels in the aquatic environment leading to various disturbing effects. In the present work, we investigated the bio-uptake of heavy metals following the exposure of Ruditapes decussatus to three concentrations of phosphogypsum, 10 g.kg⁻¹, 20 g.kg⁻¹ and 40 g.kg⁻¹, under laboratory conditions. The amounts of Zn, Cd and Pb in several organs of the clam Ruditapes decussatus was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Phosphogypsum acts on the behaviour of R. decussatus by increasing filtration rates.
The most treatments showed significantly higher metal concentration in all tissues than the controls. Excavation behaviour was altered in treated bivalves compared to controls.
The filtration rate (FR) of clams was significantly affected by exposure to phosphogypsum. Indeed, FR increased in clams exposed to phosphogypsum.
Phosphogypsum has decreased SOD, CAT and MDA activities in the gills, digestive gland, gonad and muscles according to the concentration indicating a defense against oxidative stress. AChE was significantly inhibited in clams from all the sampling sites compared to controls
The considered parameters could be useful biomarkers for the evaluation of phosphogypsum toxicity in threatened biota.
This study was conducted as part of a further investigation into the use of a comprehensive approach combining chemical and biological parameters to assess the health status of the Gabes gulf population. It provides the first database referring to phosphogypsum contamination and its biological effect in this ecosystem. The present study fills in a needed gap in the literature.
... Laboratory experiments investigating the distribution of Cd and Pb in R. philippinarum tissues showed similar bioaccumulation levels of Cd in gills and digestive gland, while Pb was predominantly accumulated in the gills (Blasco and Puppo, 1999). This latter organ has been indicated by various authors (Amiard-Triquet et al., 1986;Preston, 1971;Schulz-Baldes, 1974) as the primary organ for the bioaccumulation of metals, particularly during the initial period of exposure, due to its large surface area and the properties of the mucous covering layer. This mucous is probably contributing for the absorption of metals in dissolved and particulate forms from the water which flows through the cavity of the mantle (Cunningham, 1979). ...
The Manila clam Ruditapes philippinarum is an invasive bivalve in Europe, widely distributed, with a great ability to tolerate a broad range of environmental conditions. Despite the ability to reflect contamination, its suitability as bioindicator is not consensual. This study provided clarification on this issue by evaluating the ability of R. philippinarum to signalise trace element contamination in an estuary chronically impacted by metals and metalloids (Tagus estuary, Portugal). A multidimensional approach was carried out in two differently contaminated sites (Barreiro - BAR; Alcochete - ALC) in warm and cold periods, combining sediment contamination, bioaccumulation of trace elements (As, Cd, Pb and Hg), and a battery of oxidative stress biomarkers in two R. philippinarum organs (digestive gland and gills). Sediments from BAR exhibited higher concentrations of all the elements than those from ALC, in line with the anthropogenic pressures identified for both estuarine areas. Likewise, clams from BAR showed higher concentrations of As and Pb in the digestive gland (cold period) and Pb in the gills (warm and cold periods) in comparison with ALC. These results suggest the capacity of R. philippinarum to reflect external levels of exposure to those elements into tissue loads. However, an opposite spatial variation was consistently found for Hg accumulation in the digestive gland and gills in both periods, as well as for Cd in the gills in the warm season. The results reinforce the idea that trace element accumulation patterns depend not only on the external bioavailability, but also on the toxicokinetics that is trace element-specific. Despite the two contrasting patterns found for bioaccumulation in R. philippinarum (mainly Pb vs. Hg), oxidative stress parameters were able to signalise BAR as the most impacted area. In fact, the digestive gland of BAR clams exhibited higher GST activity and GSHt levels (in both sampling periods) and SOD activity (warm season), presumably to cope with the enhanced accumulation of Pb and As. Moreover, variations of gills' CAT and SOD activities (warm period) agreed with the elevated accumulation of Pb at BAR. Overall, the characteristics of this invasive species could lead to a biased interpretation of the environmental quality status, particularly when based on trace element bioaccumulation only, reinforcing the need to adopt a multi-level/-species approach on environmental assessment studies.
... In all fish species, lead rises only moderately with body weight (Tables 2 and 3). Generally, Pb accumulates in tissues in proportion to the ambient concentration (Tao et al. 1999), but the rate of its depuration is dependent on the overall body concentration (Schulz 1974). The liver and kidney of the three Indian major carps tend to retain the metal. ...
Concentrations of heavy metals (Cu, Ni, Zn, Cd and Pb) were measured in sediments, water and liver and kidney tissues of three Indian major carps (Labeo rohita, Catla catla and Cirrhinus cirrhosus), belonging to two different weight groups (250 and 500 g), collected from ponds at two different sites (Nalban bheri and Diamond Harbour). The tissues were analysed for the levels of different antioxidant defence systems such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GRd), glutathione S-transferase (GST), glutathione (GSH) and malondialdehyde (MDA). Concentrations of all the metals were significantly higher (P < 0.05) in sediment, water and the tissues from Nalban bheri compared to those in Diamond Harbour. Metal concentrations were the lowest in C. cirrhosus, which increased with an increase in fish weight, and the liver accumulated higher amount of metals than the kidney. Activities of all enzymatic and non-enzymatic antioxidant parameters except GPx and GRd were significantly higher (P < 0.05) in the tissues from Nalban bheri than those in Diamond Harbour. Significant multicollinearity was found in the values of SOD, CAT, GST, GRd, GPx and MDA with Pb, Cu and Ni in all three fish species at Nalban and with Cd in L. rohita and C. catla. Principal component analysis results revealed that stress response in a polluted site was directly regulated by an amalgamation of GSH profile and the levels of MDA in a synchronized manner. The study indicated a tissue-specific and species-specific difference for heavy metal-induced oxidative stress response in fish and a correlation between different heavy metals and individual oxidative stress markers.
... Böbrek dokusunda kadmiyum azalması fazla gözlenmemiştir. Bunun sebebi, metal bağlayıcı proteinlerin sentezinin yapım yerinin böbrekler olmasından (Schulz-Baides, 1974;Thomas vd. 1985;Wood, 1988) dolayı olabilir. ...
Araştırmamızda kalsiyum ve zeolitin Oreochromis niloticus balık dokularında (böbrek, karaciğer, solungaç ve kas) kadmiyum birikimi üzerine etkileri incelenmiştir. Balıklar 5, 10 ve 15 gün sürelerle 1,0 mg/L Cd, 1,0 mg/L Cd+1,0 mg/L Ca (Cd+Ca), 1,0 mg/L Cd+0,1 g/L Zeolit (Cd+ZE) karışımının etkisine bırakılmış, dokulardaki kadmiyum birikimi ICP-MS Spektrometresi ile ölçülmüştür. Dokulardaki kadmiyum derişimi sürenin uzamasıyla artmıştır. En yüksek kadmiyum birikimi böbrek dokusunda bulunmuş olup, bunu karaciğer, solungaç ve kas dokusu izlemiştir. Etkide kalınan tüm sürelerde, O.niloticus’un dokularında kadmiyum birikimi kalsiyum ve zeolitin varlığında azalmıştır. Çalışma sonucunda, kadmiyum birikiminin zeolit ve kalsiyum tarafından azaltıldığı ve bu azalışta zeolitin etkisinin, kalsiyuma göre, daha fazla olduğu saptanmıştır.
... In Mytilusedulis (a mollusc), examines on the uptake of lead demonstrated that the kidneys contained 50-70% of the aggregate lead and were the tissues which picked up and lost it most promptly [23]). Ireland and Wootton [24] reported that in both Littorina and Thais, the convergence of lead in the shell was far higher than the fixation in the delicate body; they further specified that in both species the lead substance of the shell represented around 80% of the aggregate lead content. ...
Okobaba hub of Lagos Lagoon is a water body that is presented to direct impact of sawmilling movement and other local wellsprings of contamination of the water body. The physic-concoction parameters, substantial metals and also disintegrated supplements for both water and silt tests of Lagos tidal pond at Okobaba were considered for a time of six month, tests were gathered from March to August as part of the arrangement of studies for the determination for the levels of tainting of the oceanic environment. Five stations were considered and an aggregate of thirty examples were gathered for both water and dregs tests each. Four out of the five stations extended along the water bank of Okobaba while the last (control) is taken after third terrain span. Profundity of water ranges between 0.6 m-2.2 m, temperature ranges somewhere around 240°C and 300°C for air and 250°C and 350°C in water. Complete strong in water was seen to have a scope of 7010-21104. Saltiness of water body ranges from 5.7-22.8 mg/l. Scope of qualities for DO, BOD, alkalinity and pH qualities are given as 3.5-7.4 mg/l, 2106-12104 mg/l, 36.5-105.2 mg/l and 6.7-7.9 mg/l individually. Results got demonstrated that with the exception of Chloride, suspended strong, depth and transparency, all other physic-compound parameters and broke down supplements are not altogether diverse (p>0.05). Centralization of overwhelming metals, for example, Chromium, Nickel, Zinc and Iron demonstrated noteworthy distinction (p<0.05). It was thusly presumed that the levels of sawmill waste contamination from Okobaba has brought about a contrarily noteworthy effect on the water body.
... Ancak tüm doku ve organlar karşılaştırıldığında bu azalma çok fazla olmamıştır. Bunun sebebi metal bağlayıcı proteinlerin sentezinin yapımı yerinin böbrekler olmasından (Schulz-Baides, 1974;Thomas vd., 1985;Wood, 1988) dolayı olabilir. ...
... However data on Cd and Hg are scarce; informations on the effects of sex and reproduction have to be found from studies on other metals. Schulz-Baldes (1974) observed that the Pb leve! in M. edulis changes after spawning. Walting and Walting (1976) have clearly shown differences in concentrations of Zn, Mn and Cu in Choromytilus meridonalis between mature males and females, with the latter having the highest levels. ...
... Daar is gesorg dat die spesie nie verwar is met die byna identiese uitheemse spesie Mytilus galloprovincialis nie deur van Branch et al. (2005) se beskrywing gebruik te maak. Daar is gepoog om slegs manlike eksemplare chemies te ontleed ten einde die probleem te systap wat veroorsaak word deur veranderinge in die ontwikkeling van gonades wat weer tot veranderinge in metaalinhoud kan lei (Schulz-Baldes 1974). Die onderskeid is makroskopies getref deur na grootte, vorm en kleur van gonades te kyk, hoewel kleurvariasies voorgekom het en die akkuraatheid van die metode beperk is (Petes et al. 2008), aangesien meer betroubare biochemiese metodes (Jabbar & Davies 1987) nie moontlik was nie. ...
The development of methods to monitor the South African coastal waters offer major challenges. Knowledge and availability of suitable species that may serve as biomonitors will be valuable to obtain information to support good management decisions. It is therefore important to identify local species that show the basic characteristics required for biomonitoring. The aim of this study was to compare, as part of a wider seasonal field study of metals in the intertidal zone of False Bay, South Africa, the body loads of copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd) and zinc (Zn) in the black mussel (C. meridionalis) and the barnacle (T. serrata), and to compare these with environmental concentrations. Also to draw conclusions about the animals’ relative abilities to accumulate priority metals. Specimens of both species were collected over several seasons at different points in False Bay and analysed chemically. The mean body load (soft tissue and shell) of metals was higher in the black mussel than in the barnacle during all seasons. A comparison between the body loads and environmental concentrations in water and sediment showed that the priority metals Cd, Ni and Pb are accumulated strongly by both C. meridionalis and T. serrata. The mean Cd body loads varied between 6.43 µg/g and 14.73 µg/g for the various seasons but was not statistically significantly different between seasons. Metal concentrations were in most cases highest during winter. Multiple regression analysis showed a strong correlation between body load of metals in the black mussel and the environmental concentration for most seasons, which indicates that the black mussel can be useful as an active rather than a passive biomonitor. The concept of biomonitoring has merit because it may show long-term tendencies, but it does not offer an absolute measure of immediate, varying pollution levels. It could serve as an additional management tool in a national marine programme for the protection of the intertidal zone’s biodiversity.
... Organisms have a variety of ways of avoiding these effects. The metal may be excreted so that the concentration in the animal is independent of the environment (as with Zn 2+ in Carcinus; Bryan, 1976), it may be f c r e t e d in proportion to the body load, so that the animal reflects the concentration II EXB 94 in the environment (as with Pb 2+ in Mytilus; Schulz-Baldes, 1974), or it may h« accumulated for some time so that the organism shows concentration factors thousanaB of times higher than environmental levels (as with Cd 2+ in Neiris; Bryan, 1976). Examples of this type of bioaccumulation have attracted much attention from environmentalists. ...
A technique is described for investigating cellular fluxes and the accumulation of metal ions in the hepatopancreas of the snail Helix aspersa. The method involves the simultaneous administration of double isotopes into the haemocoel and the subsequent detection of these metals in tissues and granule materials. By comparing in vivo and in vitro data it is possible to detect two separate accumulation systems which appear to correspond with metallothionein and pyrophosphate granules. It is also possible to obtain some information of the nature of possible cellular transport systems.
... Hopkin and Nott (1979) demonstrated that the shore crab (Carcinus maenas) detoxifies lead in calciferous granules in the midgut gland. The detoxification and storage of Pb in shellfish has been suggested for the zebra mussel Dreissena polymorpha (Kraak et al., 1994;Bleeker et al., 1992), the blue mussel Mytilus edulis (Schulz-Baldes, 1974), the Eastern oyster Crassostrea virginica (Shuster and Pringle, 1969;Pringle et al., 1968;Zaroogian et al., 1979), and the soft-shell clam Mya arenaria (Pringle et al., 1968). ...
... Several previous studies [47][48][49][50][51][52] report that seasonal fluctuations can be masked by shortterm pollution. A similar pattern is reported for Cd, Pb, and Cu in M. galloprovincialis from the Gulf at Trieste, Italy [53], and for Cd, Cu, and Zn in Mitylus edulis [22]. ...
... The digestive gland is a preferred site of Pb storage which is clearly shown by the highest bioconcentration factor (1.71 × 10 3 ). Linear uptake of Pb with time has been reported to continue even at longer exposure times [31]. However, in field conditions, the uptake of Pb from external environment was different from the laboratory experiment and the linearity between Pb uptake and time exposure may not be found. ...
The purpose of this study was to investigate the long-term bioaccumulation and elimination of Cd, Pb, Mn, Zn and Fe by P. nobilis tissues after their 90 day- transplantation period at Téboulba fishing harbor. During the transplantation period, the Cd, Pb, Mn, Zn and Fe concentrations in the different tissues of the mussels were measured before and after exposure period. Metal (Cd, Pb, Mn, Zn and Fe) accumulation in P. nobilis mussels varied depending on the analyzed tissue and the caging times. Notable differences in Cd, Pb, Mn, Zn and Fe accumulation patterns within the digestive gland, gills and muscle were found and may be due to the ability of each tissue to accumulate metals. During the depuration phase, the elimination of Cd, Pb, Mn, Zn and Fe depended on the target tissue and the metal speciation. Cd, Pb, Mn, and Fe were eliminated rapidly from one organ and increased in other when compared to those of 90 day transplanted mussels. The increase of metal loads during the elimination phase is not clear and particularly what kind of processes is responsible for such response. However, it is reasonable to assume that metals increase is related to the existence of an accumulation/detoxification mechanism, which involves the transport of metals from an organ to another. The data obtained indicate that because of the significantly high quantities of Cd, Pb, Mn, Zn, and Fe accumulated during the exposure phase, the transplanted mussels are suitable bioindicators for monitoring trace metals in marine ecosystem.
... Pollution of coastal waters can readily lead to contamination of molluscan shellfish. Uptake and elimination of some ofthese contaminants have been studied for a variety of compounds including heavy metals (32,34,37,64,100,126,147), petroleum hydrocarbons (51, 89,102,155), radionuclides (28,35) and toxins (11,13). Uptake and elimination of potential human pathogens and indicator organisms from shellfish are the subject of this review. ...
A review of the literature on shellfish depuration and relaying revealed wide diversity in microbial uptake and elimination among shellfish species and for different microorganisms. Information on relaying of five commercial shellfish species and on controlled purification (depuration) of 11 species indicates that such processes are effective in reducing the levels of bioconcentrated bacteria and viruses from shellfish. The degree of bacterial and viral bioconcentration varies with shellfish species; however, the primary sites of bioconcentration are the hepatopancreas and digestive diverticula. Low levels of enteric viruses and coliphage may be sequestered in shellfish hemolymph and tissues, thus protecting them from elimination through depurative processes. Vibrio spp. appear to proliferate when closely associated with intestinal cells of shellfish. Shellfish relaying techniques offer effective microbial depletion provided water quality is acceptable and shellfish remain physiologically active. The current body of literature on controlled purification demonstrates a broad spectrum of conditions under which shellfish are depurated. Optimal times, temperatures and salinities for effective depuration vary among shellfish species. Proper design and operation of depuration plants is crucial to insure process integrity. Recirculating and flowthrough purification systems are effective in reducing the levels of pathogenic and indicator microorganisms from shellfish, but the extent to which they reduce viruses from shellfish is uncertain. Studies are needed to validate the effectiveness of depuration processes in eliminating pathogenic viruses and to address the adequacy of indicator bacteria as measures of enteric virus contamination.
Coastal ecosystems are ecologically and economically important but are under increasing pressure from numerous anthropogenic sources of stress. Both heavy metal pollution and invasive species pose major environmental concerns that can have significant impacts on marine organisms. It is likely that many stresses will occur simultaneously, resulting in potential cumulative ecological effects. The aim of this study was to compare the relative resilience of an invasive oyster Magallana gigas and a native mussel Mytilus edulis to heavy metal pollution, utilising their valve gape response as an indicator. The gape activity of bivalves has been utilised to monitor a range of potential impacts, including for example oil spills, increased turbidity, eutrophication, heavy metal contamination etc. In this study, Hall effect sensors were used on both the native blue mussel (M. edulis) and the pacific oyster (M. gigas), invasive to Ireland. Mussels were shown to be more responsive to pollution events than oysters, where all heavy metals tested (copper, cadmium, zinc, lead) had an effect on transition frequency though significant differences were only observed for lead and cadmium (Control; > Copper, p = 0.0003; >lead, p = 0.0002; >Cadmium, p = 0.0001). Cadmium had an apparent effect on mussels with specimens from this treatment remaining closed for an average of 45.3% of the time. Similarly, significant effects on the duration of time mussels spent fully open was observed when treated with lead and cadmium (Control; > lead, p = 0.03, > cadmium, p = 0.02). In contrast, oysters displayed no significant difference for any treatment for number of gapes, or duration spent open or closed. Though there was an effect of both zinc and copper on the amount of time spent closed, with averages of 63.2 and 68.7% respectively. This indicates oysters may be potentially more resilient to such pollution events; further boosting their competitive advantage. Future mesocosm or field studies are required to quantify this relative resilience.
Molluscs, owing to their filtrate ability, can accumulate metals that may
contaminate food, causing a negative impact on the health of the consumers. Thus,
the main objective of the present study was to investigate the heavy metal
concentrations in one of the widest broad and consumed surf clams Mactra olorina
available in the Great Bitter Lake, Egypt. The concentrations of the heavy metals
(Pb, Cd, Cu, and Zn) were seasonally evaluated in water, sediment, and the soft
flesh of M. olorina. The specimens were monthly collected from the Egyptian
Great Bitter Lake near Fayed City (Ismailia Governorate) for one year , from April
2009 to March 2010. Results revealed that, the annual mean concentrations of
heavy metals in water were 1.376±0.562, 0.267±0.329, 2.256±2.909 and
3.355±2.731 μg/l for Pb, Cd, Cu and Zn, respectively. The corresponding
concentration values in the sediment were 0.398±0.355, 0.307±0.244, 1.753±0.464
and 8.643±1.821 for Pb, Cd, Cu and Zn μg/g, respectively. While, the annual mean
concentrations of heavy metals in soft tissues were 0.538±1.130, 0.262±0.283,
5.395±3.115 and 13.043±5.743 for Pb, Cd, Cu, and Zn μg/g, respectively.
Interestingly, heavy metals deposited in the tissues of M. olorina and their
environment (water and sediments) recorded a close relationship (0.05 ≥ p ≤0.01)
in the current research. In conclusion, though no apparent risk was detected on
bivalve consumers from being exposed to a single metal, yet there is a risk from
being exposed to the 4 studied metals combined together, especially for high
bivalve-consuming groups such as fishermen. Furthermore, environmental
parameters need to consider when to use bivalves as indicators of heavy metal
pollution since seasonality could affect the absorption of heavy metals.
The goal of this study was to quantify the content of heavy metals (Zn, Cu, Cd, Pb, Hg) in the bivalve Mytilus galloprovincialis, which was obtained from the Black Sea's Sinop peninsula, as well as estimate the health risks. Concentrations of heavy metals in mussels' soft tissues ranged between 16.4-21.8, 0.52-0.93, 0.13-0.45; 0.015-0.019 and 0.006-0.011mg kg-1 wet weight for Zn, Cu, Pb, Hg and Cd, respectively. In general, metal concentrations in mussels were quite low. In mussels, Zn was the most prevalent element, followed by Cu. Regarding the monthly variation, although relatively higher tissue metal concentrations were observed in August compared to July, no statistical difference was found. The estimated daily intakes did not exceed the tolerable intakes. There was no health risk since the total hazard index was far below critical value 1. This demonstrates that eating mussels from the Sinop coasts in 2019 does not cause any health risks in infants, children, or adult. Mussels have a risk index of less than 10-6 , which is considered insignificant. In conclusion, the results of this study show that there is no heavy metal pollution in the mussels collected from Sinop coasts.
La capacité bioindicatrice des mollusques bivalves vis-à-vis des métaux est actuellement reconnue et utilisée dans le cadre du biomonitoring. La compréhension de cette capacité nécessitait une étude plus fondamentale des voies d'intoxication, de transport et d'élimination des métaux. Une étude anatomique, cytologique et microanalytique des hémocytes, de la glande péricardiale et des reins a montré le rôle des granulocytes dans le transport puis le rôle de détoxication de la glande péricardiale et des reins. Le système lysosomal joue un rôle important. La nature du métal modifie la répartition au sein des organes. Le plomb est bioconcentré en association avec P, S, Ca dans les concrétions des cellules du rein distal. La microanalyse de rayons x a été, à ce titre performante. Une adaptation éventuelle à la présence de micropolluants métalliques a été recherchée par numération des hémocytes, suivi de l'activité enzymatique et des capacités de phagocytose. Il y a tendance à l'augmentation du nombre des hémocytes ; augmentation de l'activité phosphatasique acide mais pas de modification significative de l'activité de phagocytose. Les réponses cytochimiques et biochimiques des hémocytes en présence de métaux peuvent être proposées comme méthodes d'évaluation précoce (7 jours) des effets de la contamination des eaux par les métaux ; le niveau de bioaccumulation étant évalué par la méthode des transplantations seulement après trois semaines
In comparison with the open oceans, the estuaries and shallow coastal seas (continental shelf regions) are very productive and contribute most of the world catch of fin-fish and shell-fish. These coastal regions are the principal mixing zones where river-water, atmospheric dust and rain are mixed with salty water to form shelf-water and eventually oceanic water. The concentration of inorganic elements in shelf-water and their impact on marine organisms depend on the chemical species that are formed. This in turn depends on their tendency to interact with other inorganic and organic material in solution, with suspended inanimate material and with the bottom sediment of the sea-bed. Regional circulation such as tides, winds and water upwelling, as well as uptake into marine life forms and mineralising processes determine the amounts of the inorganic elements from the land run-off that are either trapped in the coastal boundary zone or ultimately injected into the open ocean.
Das Wort “Pollution„ ist der heute gängige Terminus technicus für schädliche Substanzen, die in unserer Umwelt durch menschliche Aktivitäten freigesetzt werden. Manchmal wird auch der Rauch von einem Waldbrand, der von einem Blitzschlag herrührt, oder das Schwefeldioxyd von einem Vulkanausbruch als Pollution bezeichnet. Ein “Pollutant„ kann ein einfaches chemisches Element sein wie Blei oder Quecksilber, eine chemische Verbindung wie DDT oder Kohlenmonoxyd, oder eine kompliziertere Kombination verschiedener Materialien wie etwa Staub oder Müll. Geräusch, Strahlung und Abwärme werden vielfach ebenfalls als Pollutantien angesehen. Entsprechend der Verschiedenheit der Pollutantien gibt es eine große Breite von Wirkungen. Aus praktischen Gründen sollen sie in vier Kategorien eingeordnet werden:
1.
Direkte Wirkungen auf die Gesundheit des Menschen (beispielsweise Bleivergiftung).
2.
Einwirkungen auf menschliche Güter und Dienstleistungen (korrodierende Wirkung von Pollutantien auf Gebäude).
3.
Andere direkte Folgen für die „Lebensqualität“ (besondere Gefahr von Pollutantien in Ballungszentren).
4.
Indirekte Folgen für die Gesellschaft durch Einwirkung auf Ökosysteme, die vom Menschen ausgenutzt werden. Beispiele für solche indirekten Effekte sind die Zerstörung der Vegatation und die Vergiftung von Küstengewässern mit Schweröl und Schwermetallen.
The acute toxicity of a range of alkyl lead compounds including tetra methyl and tetra ethyl lead and their tri alkyl and di alkyl degradation products has been determined with four marine phyla. An alga (Phaeodactylum tricornutum), a mollusc (Mytilus edulis), a crustacean (Crangon crangon) and a fish (Pleuronectes platessa).
This chapter provides a general understanding of metal ion involvement in the various physiological compartments of the mollusk. Five elements—potassium, sodium, magnesium, calcium, and chlorine—are involved in establishing the ionic composition of the intracellular and extracellular fluids. These elements are also manipulated by cells so as to produce the osmotic equilibria that are necessary for living systems. There is a large group of elements that are required in only trace amounts for a whole variety of metabolic activities. Many of these elements are metals and they perform a wide variety of functions of which the activity of metalloenzymes, the transport of oxygen, and redox activities are the best understood. A large number of metalloenzymes and metal ion-activated enzymes are now known. Some metals, such as zinc and magnesium, are frequently associated with enzymes, although they may not be structurally a part of the molecule. A second major group of metal-dependent functions involves the respiratory pigments.
Most of the thousands of substances and species that risk assessment has to deal with are not investigated empirically because of financial, practical, and ethical constraints. To facilitate extrapolation, we have developed a model for concentration kinetics of inorganic substances as a function of the exposure concentration of the chemical and the weight and trophic level of the species. The ecological parameters and the resistances that substances encounter during diffusion in water layers were obtained from previous reviews. The other chemical parameters (the resistances for permeation of lipid layers) were calibrated in the present study on 1,062 rate constants for absorption from water, for assimilation from feud, and for elimination. Data on all elements and species were collected, but most applied to aquatic species, in particular mollusks and fish, and to transition metals, in particular group IIB (Zn, Cd, Hg). Their ratio was validated on 92 regressions and nine geometric averages, representing thousands of (near-)equilibrium accumulation ratios from laboratory and field studies. Rate constants for absorption and elimination decreased with species weight at an exponent of about -0.25. known from ecological allometry. On average, uptake-rate constants decreased with about the reciprocal square root of the exposure concentration. About 71 and 30% of the variation in absorption and elimination was explained by the model, respectively. The efficiency for assimilation of elements from food appeared to be determined mainly by the food digestibility and the distribution over egested and digested fractions. (Near-)equilibrium accumulation and magnification ratios also decreased with the reciprocal square root of the exposure concentration. The level of the organism-solids concentrations ratios roughly varied between one and two orders of magnitude, depending on the number of elements and species groups investigated. Metal concentrations did not increase at higher trophic levels, with the exception of (methyl-)mercury, Organism-solids concentration ratios for terrestrial species tended to be somewhat lower than those for their aquatic equivalents. Food web accumulation, expressed as organism-organic solids and organism-food concentrations ratios, can therefore be only partly explained by ecological variables. The model is believed to facilitate various types of scientific interpretation as well as environmental risk assessment.
With a possibilities to use the foot of the mussel Mytilus galloprovincialis as a quantitative bioindicator of lead pollution of an aquatic area, three age groups (A=1, B=1.5 and C=2 years) were kept seven days in a tank with increased Pb levels. After seven days of Pb solution supply the rate of lead loss from mussel foot was observed. The process of metal accumulation versus time has showed slight exponential increase, whereas the metal excretion has been linear.
In the course of establishing mussels as monitoring organisms for heavy metal pollution the kinetics of lead uptake into the soft parts of Mytilus edulis have been studied. The differences in organ specific uptake rates reflect the pathway of lead into and within the animal. Lead is taken up at gills and viscera, distributed by the blood and finally stored in membrane bound vesicles within excretory cells of the kidney as demonstrated by electron microscopy and x-ray-microanalysis.
Food chains consist of variable numbers of trophic levels linked in successive prey and predator relationships. Networks of these chains form complex food webs that route the supply, transfer and disposal of potentially toxic metals within ecological systems. Metals are transferred along the chains but they differ from the organic constituents of food in two main respects. Firstly, they can enter food chains directly from solution in sea-water by crossing permeable membranes of marine organisms. Within tissues they are compartmentalized in membrane-limited vacuoles and bound to ligands to reduce the toxic reactivity (Mason and Nott, 1981; Brown, 1982; George, 1982; Taylor and Simkiss, 1984; Roesijadi, 1992; Viarengo and Nott, 1993). These processes remove metals from tissue fluids, and diffusion gradients inwards from seawater are maintained; concentration factors in excess of a thousand-fold can be attained. Concentration factors represent the net balance of continuous uptake and excretion, which can result in negligible or excessive accumulation according to the metal and its availability and the species of organism (Baudo, 1981, 1985; Bryan, 1976b, 1979; Fowler, 1982; Suedel et al., 1994). Uptake by a particular species can be modified by stage of life history, physiological acclimation and genetic adaptation (Chapter 7).
In this study, the accumulation of lead in various tissues of Tilapia zilli was tested at varying concentrations of lead in the medium for different exposure times. Experimental animals were exposed to 1.0, 2.5 and 5.0 ppm lead over periods of 1, 7, 15 and 30 days and accumulation of lead in gill, liver, kidney and brain tissues was determined by atomic absorbtion spectrophotometry (AAS). In general, the accumulation of lead in tissues increased with increasing concentrations of lead in the experimental medium and with increasing time of experiment. The ratios of total lead in the tissues were 15.47, 6.10, 52.87 and 25.56% in the gill, liver, kidney and brain respectively (Kidney > Brain > Gill > Liver). The high level of lead accumulation in the kidney tissue may be explained by the fact that this tissue contains lead combaining proteins, and a high level of metal is disposed of with the aid of kidney tissue.
Mercury, cadmium and copper which are heavy metal widely used in industry and contaminate aquatic ecosystems as toxic pollutants, were investigated for acute toxicity to the golden apple snail, Pomacea sp. The bioassay experiments in static water system were undertaken to determine the 24-, 48-, 72- and 96-hour mean lethal concentrations for the snail. The experiments were repeated three times. In addition, behavioral and morphological changes of exposed snails at each metal concentration were observed. Data obtained from the acute toxicity tests were evaluated using the probit analysis statistical method. The 24-hour LC50 values (upper and lower 95% confidence limits) for the snail were estimated as 1.57 mg/1 (0.92 and 2.67 mg/l) of mercury, 2.25 mg/l (1.24 and 4.66 mg/l) of cadmium and 4.84 mg/l (3.17 and 8.35 mg/l) of copper. The 48-hour LC50 values were estimated as 0.57 mg/l (0.22 and 0.96 mg/l) of mercury, 2.07 mg/l (1.54 and 3.54 mg/l) of cadmium and 1.85 mg/l (1.06 and 0.90 mg/l) of copper. The 72-hour LC50 values were estimated as 0.17 mg/l (0.07 and 0.26 mg/l) of mercury, 0.68 mg/l (0.48 and 0.90 mg/l) of cadmium and 0.92 mg/l (0.64 and 1.78 mg/l) of copper. The 96-hour LC 50 values were estimated as 0.07 mg/l (0.05 and 0.10 mg/l) of mercury, 0.47 mg/l (0.28 and 0.84 mg/l) of cadmium and 0.12 mg/l (0.08 and 0.17 mg/l) of copper. Based on LC50 values after 24-, 48-, 72- and 96-hour exposure, mercury was more toxic than cadmium and copper. At the 24- and 72-hour cadmium was more toxic than copper. Conversely, at the 48- and 96-hour copper was more toxic than cadmium. In the metal bioaccumulation experiment, residues of mercury, cadmium and copper in the freshwater snail, Pomacea sp. were shown to be 334.91 mg/kg dry weight, 126.56 mg/kg dry weight and 125.46 mg/kg dry weight, respectively after 96 hours. Copper was accumulated the least, while mercury was present in the greatest concentration. The results of this study indicate the possibility of using freshwater snail, Pomacea sp. as a biomonitor for heavy metal contaminants in freshwater resources.
As practical biologists, we know that the terrestrial ecosystem is resilient. Minor episodes of pollution are soon corrected or compensated for if nature is given a chance. We know that there is no single, simple balance of nature to be upset. There are many balances, and they shift constantly as summer changes to winter, as drought follows flood, and as erosion follows fire. Among the most powerful factors are our own work: cultivation, exploitation, and construction. Pollution, therefore, is just one factor.
There are about 128,000 species of molluscs. There are five major groups in this phylum: the pelycopods, with 20,000 recent species, including clams, oysters, mussels, cockles, and scallops; gastropods, comprising 105,000 species, such as the drills, conchs, cowries, whelks, nudibranchs, and mud snails; about 750 species of cephalopods, including octopus, squid, and cuttlefish; 305 species of scaphopods; and about 1000 species of amphineurans, including the chitons. Molluscs are unsegmented coelomate animals with a well-developed head, a ventral muscular foot, and a dorsal visceral hump; with soft skin, partly covering the visceral hump and the mantle, and often secreting a calcareous shell. Molluscs are characterized by a complex anatomy and highly diverse specializations. Many are of large size, especially the giant squids. Extensive monitoring programs have been implemented, mainly with mussels, to assess potentially toxic metals and other contaminants in marine environments. Although mussels are recommended as indicator organisms, additional biological variables need to be investigated, along with water and sediment analyses. In general, the highest concentrations of all metals and metalloids examined in marine molluscs were in gut and digestive glands, with moderate enrichment in gills, mantle, and gonads, and lowest residuals in muscle and shell. It is also now generally accepted that mussels from highly industrialized areas contain significantly higher levels in tissues of copper, lead, cobalt, chromium, nickel, iron, manganese, and other elements.
Current concepts of metal metabolism have been reviewed with a view to understanding the factors that influence the uptake, storage, detoxication and elimination of essential and pollutant trace metals in aquatic organisms. Particular emphasis has been given to estuarine and coastal biota, which are more at risk from metal pollution.
In their natural habitats, organisms are exposed to multiple stressors. Heavy metal contamination stresses the cell membrane due to increased peroxidation of lipids. Likewise, sub-zero air temperatures potentially reduce membrane functionality in ectothermal animals. We tested if acute lead (Pb) exposure for 7 days would influence survival in intertidal blue mussels (Mytilus edulis) after exposure to realistic sub-zero air temperatures. A full factorial experiment with five tissue Pb concentrations between 0 and 3500 μg Pb/g and six sub-zero temperatures from 0 to -17 °C were used to test the hypothesis that sub-lethal effects of Pb may increase the lethality caused by freezing in blue mussels exposed to temperatures simulating Greenland winter conditions. We found a significant effect of temperature on mortality. However, the short-term exposure to Pb did not result in any effects of Pb, nor did we find interactions between Pb and temperature. We analysed the relative abundance of major phospholipid fatty acids (PLFAs) in the gill tissue, but we found no significant effect of Pb tissue concentration on PLFA composition. Results suggest that Pb accumulation has limited effects on freeze tolerance and does not induce membrane damage in terms of persistent lipid peroxidation.
Lead is a member of the Group IV elements (C, Si, Ge, Sn, and Pb) of the periodic classification. The electropositive character in this group increases with atomic number and lead is truly metallic compared to carbon and silicon. Lead, unlike C and Si, does not bind to another identical atom, shows marked decrease in covalency, and has stable (+2) and (+4) oxidation states. Members of group IV form organo derivatives. Lead forms alkyl and aryl compounds. Tetraethyllead is widely used as an antiknock agent in gasoline. With the exception of nitrate and acetate, most lead(+2) salts are insoluble in water.
Increasing urbanization and industrialization along the coastal areas of False Bay in South Africa can endanger coastal ecosystems because of increasing metal pollution. To obtain base-line data on contamination levels in the intertidal zone, cadmium (Cd) body loads of four invertebrate species were measured seasonally over a period of 15 months from different sites within the bay. Specimens of Tetraclita serrata (barnacle), Oxystele sinenses (periwinkle), Cymbula oculus (limpet) and Choromytilus meridionalis (mussel) were collected and analysed to determine temporal changes in Cd body burdens. Cd concentrations were also measured in water and sediments. Cd concentrations in the intertidal animals varied considerably between sampling sites and between seasons and also occasionally between species. All four species accumulated Cd in their bodies to levels several times higher than environmental concentrations. No significant difference could be shown between the Cd concentrations in the gastropod grazers and the filter-feeders. The highest mean body load of Cd (70.67 µg/g dry weight) for a single sampling occasion was measured in the sessile barnacles (T. serrata) collected at Rooi-Els. The highest mean Cd concentration (11.95 µg/g) for the bay as a whole was measured in the limpet C. oculus. Two-way analysis of variance indicated that spatial (location) rather than temporal (seasonal) factors affected Cd concentrations in the invertebrates. Cd concentrations in False Bay sometimes exceeded the norms or water quality standards.
This study deals with the transfer of heavy metals (Hg, Cd, Pb, Cr, Ni, Ti, Zn, and Cu) between abiotic and biotic components (Cytheria chione and Cerastoderma edule) in the inshore intertidal zones of Tetouan/Martil over 2 yr of investigation (1992–1994). Analysis of the heavy-metal accumulation kinetics in Cytheria chione and Cerastoderma edule shows that their highest contents occur during the spring–summer period when an important proliferation of the plankton biomass occurs. However, the accumulation of Cd is higher during the period between winter and spring. In general, heavy-metal concentrations are higher at Cytheria chione than at Cerastoderma edule. These results, according to previous studies, suggest the presence of significant correlations and dynamic reciprocal transfer of heavy metals among seawater, sediment, and molluscs. They also suggest that the level of contamination of decreasing heavy metals follows the sequence: sediment, organisms, and water. Among the molluscs investigated, the variability of the thallium (Tl) contents is difficult to detect due to the very weak presence of this metal in the analysed tissues.
In the present study, the destruction of the basement membrane of the hepatic tubules and cell surface of the digestive cells after cadmium exposure probably caused disfunction of the surface receptors resulting in the disturbance of the lysosomal system functioning.
The green mussel Perna viridis (Bivalvia: Mytilacea) was exposed to a range of dissolved concentrations of Cd, Cu, Pb and Zn for 21 d. Accumulation of Zn has been interpreted in terms of a regulation mechanism to maintain constant body concentrations at ca 100 ~g Zn g-' dry wt at external dissolved Zn levels up to a threshold concentration (between 178 and 362 pg Zn I-'). Beyond this threshold, net accumulation of body Zn continued until body Zn concentration reached a plateau at 200 pg Cadmium, Cu and Pb were linearly accumulated by P. viridis in proportion to ambient metal concentrations over 7 d. Toxicity of Cd, Cu, Pb and Zn was evaluated in 96 h bioassays; LC-50 values in pg 1-' were 620 for Cu, 1570 for Cd, 6090 for Zn, and 8820 for Pb.
Each book has two main goals 1. Determine baseline concentrations of metals and metalloids in tissues of representative field populations of estuarine coastal, and open ocean organisms (Book 1:algae and macrophytes, protists, sponges, coelenterates, molluscs, crustaceans, insects, chaetognaths, annelids, echinoderms, and tunicates) (Book 2: elasmobranchs, fishes, reptiles, birds, mammals) and their significance to organism health and to the health of their consumers. 2. Synthesize existing information on biological, chemical, and physical factors known to modify uptake, retention, and translocation of each element under field and laboratory conditions. Recognition of the importance of these modifiers and their accompanying interactions is essential to the understanding of metals kinetics in marine systems and to the interpretation of baseline residue data. Synthesizes existing information on biological, chemical, and physical factors known to modify uptake, retention, and translocation of each element Aids understanding of metals kinetics in marine systems Allows the interpretation of baseline residue data.
In the present study, pristine carbon nanotube (p-CNT) and thiolated carbon naotube (t-CNT) electrodes were investigated to improve their detectabilities for cadmium (Cd) and lead (Pb). In addition, we evaluate which reaction mechanism is used when the electrolyte contains both Cd and Pb metals. Square wave stripping was employed for analyzing the sensitivity for the metals. A frequency of 30 Hz, a deposition potential of -1.2 V vs. Ag/AgCl and a deposition time of 300 s were used as optimal SWSV parameters. t-CNT electrodes show the better sensitivity for both Cd and Pb metals than that of p-CNT electrodes. In case of Cd, sensitivities of p-CNT and t-CNT electrodes were and , respectively, while the sensitivities for Pb were (p-CNT) and (t-CNT), respectively. The better sensitivity of p-CNT electrodes is due to the enhancement in the reaction rate of metal ions that are facilitated by thiol groups attached on the surface of CNT. When sensitivity was measured for the detection of Cd and Pb metals present simultaneously in the electrolyte, Pb indicates better sensitivity than Cd irrespective of electrode types. It is ascribed to the low standard electrode potential of Pb, which then promotes the possibility of oxidation reaction of the Pb metal ions. In turn, the Pb metal ions are deposited on the electrode surface faster than that of Cd metal ions and cover the electrode surface during deposition step, and thus Pb metals that cover the large portion of the surface are more easily stripped than that of Cd metals during stripping step.
The concentrations of copper, zinc, lead and cadmium in the living tissue of the Mediterranean mussel Mytilus galloprovincialis from the Sinop coasts of the Black Sea were measured by atomic absorption spectrophotometry for monitoring metal pollution in the coastal water. A statistically significant difference in the concentrations of all metals was observed among four sampling stations. The results were compared with previous studies and discussed. Karadeniz'in Sinop Kıyılarından Toplanan Akdeniz Midyesi Mytilus galloprovincialis Lamarck, 1819'lerde Bakır, Çinko, Kurşun ve Kadmiyum Konsantrasyonları Özet: Karadeniz'in Sinop kıyılarından toplanan Mytilus galloprovincialis'ların dokularında bakır, çinko, kurşun ve kadmiyum konsantrasyonları kıyısal suların metal kirliliğini belirlemek amacıyla atomik absorpsiyon spektrofotometresiyle ölçülmüştür. Elde edilen ağır metal konsantrasyonları örneklenen üç istasyon arasında istatistiksel olarak farklılık göstermiştir. Sonuçlar önceki çalışmalarla karşılaştırılmış ve tartışılmıştır.
Synopsis
The Clyde Estuary receives a relatively high pollutant load derived from the domestic and industrial wastes of half of Scotland's population. In order to monitor contaminant concentrations throughout the area, the Clyde River Purification Board (CRPB) initiated in 1980 an extensive ‘mussel-watch’ programme, having selected the common mussel as the most suitable indicator organism.
This 1980 survey served not only to identify shores with elevated trace metal concentrations and those which were relatively unpolluted, but also to assess changes in overall contamination of the area in comparison with previous surveys.
Following the success of the 1980 survey it has been gradually extended over the years, both in the number and geographical spread of sites visited, and in the substrates and determinands measured, as the CRPB's monitoring requirements have changed.
The 1984 CRPB ‘mussel-watch’ survey involved the collection of over 1200 mussels at twenty-four sites throughout the Firth of Clyde (Fig. 1), with subsequent determination of concentrations of the trace metals Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn, and of other toxic, persistent substances such as organochlorine pesticides and PCB residues.
Attention is focussed here on trace metal body burdens for Clyde mussels collected during the 1984survey.
The results of spectrographic analyses of ten species of zooplankton are presented. The methods used are described in detail. The elements determined quantitatively were boron, molybdenum, vanadium, nickel, cobalt, titanium, chromium, lead, tin, and copper. Manganese, cesium, rubidium, barium, strontium, and silver were detected in some or all of the specimens. Antimony, germanium, gallium, gold, and arsenic were sought for but not found. Cadmium was just detectable in only one species, the squid Ommastrephes ( Illex ) illecebrosa . The analytical results support the view that boron is actively concentrated or excluded by some marine animals. There is evidence that sedimentation of pteropod shells could be a major pathway for the removal of vanadium and lead from sea water. Lead was greatly enriched in Centropages . Nickel and cobalt showed random variations with respect to one another.
Over a period of 6 weeks in aquaria, Portuguese oysters Crassostrea angulata, accumulate 65Zn to a greater extent than do native Ostrea edulis, although intake rates for any particular organ in either species are quite similar. The general distribution pattern of radioactivity in the tissues is similar to that observed for stable zine and 65Zn in other oyster species, concentration occurring to the greatest extent in gills and mantle, and least in muscle. The observed equilibrium concentrations and biological half-lives are considerably less than those measured in the natural environment, and the significance of this and its bearing on the mechanism of uptake is discussed. Cobalt and iron depress the rate of 65Zn uptake by both oyster soft tissues and the shell. The limiting effect in soft tissues is probably due to competition for sites at the actual point of uptake. The distribution of 65Zn in tissue subcellular fractions separated by centrifugation shows the greatest concentration of the radioisotope in the insoluble tissue components of gills, mantle and heart. Appreciable amounts of 65Zn are associated with tissue proteins.
Spectrographic determinations of Ag, Cd, Cr, Cu, Fe, Mn, MO, Ni, Pb, Sb, V, and Zn were carried out on three spccics of New Zealand bivalves. Analyses were performed on the sediment, on the whole animals excluding shells, on the shells, and on the individual dis- scctcd organs. All the elements concerned showed more enrichment in the shellfish than in the marinc environment. Conclusions have been rcnched concerning the gcochcmical and biochemical processes involved in trace elcmcnt uptake by the biosphere. It has been known for many years that the concentration of heavy metals is sig- nificantly higher in the marine biosphere than in the hydrosphere (Cornet 1919; Noddack and Noddack 1939; Clarke and Wheeler 1922). Much of this early work has been summarized by Vinogradov (1953), but his compilations show few gross analy- ses of individual organisms, and much of the work referred to was conducted by ques- tionable experimental techniques. More rc- cent reviews by Goldberg ( 1957, 1961a, b ) have highlighted an increasing interest in the biosphere, particularly in relation to trace element uptake by marine organisms. In recent work on marine plants (Spooner 1949; Goldberg 1952; Collier 1953; Black and Mitchell 1952) and on marine animals (Carlisle 1958; Goldberg, McBlair, and Tay- lor 1951; Bowen and Sutton 1951; Jodrey 1953; Korringa 1952; Nicholls, Curl, and Bowen 1959; Saiki, Okano, and Mori 1955; Martin and Goldberg 1962; Goldberg 1962), attempts have been made to interpret the ex- perimental results in the light of modern chemical theory. In spite of this rcccnt work, the mecha- nisms whcrcby trace elements are concen- trated in the marine biosphcrc arc still not well undcrs tood, although the following pathways have been suggested:
Radioactive tracers were used to confirm and establish methods for the
separation and concentration of copper, chromium, lead, and manganese from sea
water, prior to the determination of their concentrations spectrophotometrically.
Detailed procedures are given for the determination of these elements at their
natural concentrations in sea water. Average values found for soluble copper
range from 0.9 to 1.5 mu g per liter; for chromium 0.13 to 0.25 mu g per liter;
for lead 0.6 to 1.5 mu g per liter; and for manganese 0.6 to 1.4 mu g per liter.
These four elements were found in sea water in association with suspended solid
matter, which was removed by passing the sea water through filters capable of
retaining particles with a dianaeter greater than about one micron. Procedures
are given for the spectrometric determination of copper, chromium, lead, and
manganese on the separated solids. (auth)
NO data are available for the concentration or distribution of trace
metals in coastal waters to the west of England and Wales, including the
toxic metals such as cadmium, lead, copper and zinc. This deficiency is
particularly serious considering the nature and amounts of natural
runoff and waste effluent present in these waters.
INTRODUCTION
In common with other plants, marine phytoplankton will only thrive if they are able to obtain essential trace elements. There is some evidence that shortages of available iron and manganese may occasionally restrict the growth of these organisms (Harvey, 1939, 1947). However, other essential trace metals are present in the sea at concentrations which, although very low, appear to be adequate to sustain abundant growth. The concentrations of trace elements necessary for optimum growth differ considerably from species to species (see e.g. Harvey, 1947; Goldberg, 1952). Krauss & Porter (1954) have demonstrated that manganese, iron and zinc are taken up by the freshwater alga Chlorella pyrenoidosa in proportion to their concentrations in the medium. However, this is not true for all elements, at least so far as the larger algae are concerned (Young & Langille, 1958). The concentrations of trace elements present in phytoplankton grown in culture may also depend on the age and density of the culture. Thus, Hayward (1969) has shown that although iron and zinc were initially rapidly taken up by Phaeodactylum tricornutum from a medium rich in chelated forms of these metals, their concentrations in the cells decreased as their numbers increased. The uptake of trace elements is not confined to those which have a definitely established physiological function.
The accumulation from sea water of ⁶⁵ Zn, ⁵⁴ Mn, ⁵⁹ Fe and ⁵⁸ Co by the mussel, Mytilus edulis, has been studied in relation to the stable element levels of these isotopes both in the sea water and in individual tissues. For all four radionuclides the greatest accumulation occurred in the stomach and digestive gland samples and further localization of ⁶⁵ Zn and ⁶⁹ Fe was demonstrated by autoradiography. As the animals were starved during the accumulation period the loss of stable elements by individual tissues was also followed. Again the most notable effect occurred in the digestive gland tissues with the exception of a large loss of iron by the foot. Autoradiography showed that after two weeks accumulation ⁵⁹ Fe occurs in large clusters in the foot, notable in the byssus gland area. These clusters disappear after a further two week period and may thus be secreted into new byssus threads.
A comparison has been made between the concentrations of eleven trace metals in the tissues of two species of scallops, Pecten maximus (L.) and Chlamys opercularis (L.), collected from the same area of the English Channel. Although there was considerable variation between individual animals, the mean concentrations of Ag, Co, Cr, Cu, Mn, Ni, Pb and Zn were higher in the whole body of Chlamys than in Pecten but concentrations of Al, Cd and Fe were lower. In both species, seasonal changes in the concentrations of Co, Cu, Fe, Mn, Ni, Pb and Zn were observed and, in general, the highest values were found in the autumn and winter months. These changes may be related to food supply, since concentrations were generally highest when phytoplankton productivity was low and tended to fall in the spring as productivity increased rapidly to its annual peak. Despite problems arising from individual and seasonal variation, the kidneys and digestive gland of scallops appear to have potential as biological indicators of trace metals.
The results obtained for Pecten and Chlamys are compared with those in the literature for species from the family Pectinidae.
Filtration rates and the extent of phagocytosed food particles were determined in the offshore lamellibranchs Artica islandica and Modiolus modiolus in relation to particle concentration, body size and temperature. Pure cultures of the algae Chlamydomonas sp. and Dunaliella sp. were used as food. A new method for determining filtration rates was developed by modifying the classical indirect method. The concentration of the experimental medium (100%) was kept constant to 1%. Whenever the bivalves removed algae from the medium, additional algae were added and the filtration rate of the bivalves expressed in terms of percentage amount of algae added per unit time. The concentration of the experimental medium was measured continuously by a flow colorimeter. By keeping the concentration constant, filtration rates could be determined even in relation to different definite concentrations and over long periods of time. The amount of phagocytosed food was measured by employing the biuret-method (algae cells ingested minus algae cells in faeces). Filtration rates vary continuously. As a rule, however, during a period of 24 h, two phases of high food consumption alternate with two phases of low food consumption during which the mussels' activities are almost exclusively occupied by food digestion. Filtration rate and amount of phagocytosed algae increase with increasing body size. Specimens of A. islandica with a body length of 33 to 83 mm filter between 0.7 to 71/h (30–280 mg dry weight of algae/24 h) and phagocytose 21 to 122 mg dry weight of algae during a period of 24 h. The extent of food utilization declines from 75 to 43% with increasing body size. In M. modiolus of 40 to 88 mm body length, the corresponding values of filtration rate and amount of phagocytosed algae range between 0.5 and 2.5 l/h (20–100 mg dry weight of algae) and 17 to 90 mg dry weight of algae, respectively; the percentage of food utilization does not vary much and lies near 87%. Filtration rate and amount of phagocytosed algae follow the allometric equation y=ax
b. In this equation, y represents the filtration rate (or the amount of phagocytosed algae), a the specific capacity of a mussel of 1 g soft parts (wet weight), x the wet weight of the bivalves' soft parts, and b the specific form of relationship between body size and filtration rate (or the amount of phagocytosed algae). The values obtained for b lie within a range which indicates that the filtration rate (or the amount of phagocytosed algae) is sometimes more or less proportional to body surface area, sometimes to body weight. Temperature coefficients for the filtration rate are in Arctica islandica Q10 (4–14C)=2.05 and Q10 (10–20C)=1.23, in Modiolus modiolus Q10 (4–14C)=2.33 and Q10 (10–20C)=1.63. In A. islandica, temperature coefficients for the amount of phagocytosed algae amount to Q10 (4–14C)=2.15 and Q10 (10–20C)=1.55, in M. modiolus to Q10 (4–14C)=2.54 and Q10 (10–20C)=1.92. Upon a temperature decrease from 12 to 4C, filtration rate and amount of phagocytosed algae are reduced to 50%. At the increasing concentrations of 10106, 20106 and 40106 cells of Chlamydomonas/l offered, filtration rates of both mollusc species decrease at the ratios 3:2:1. At 12C, pseudofaeces production occurs in both species in a suspension of 40106, at 20C in 60106 cells of Chlamydomonas/l. At 12C and 10–20106 cells of Chlamydomonas/l, the maximum amount of algae is phagocytosed. At 40106 cells/l, the amount of phagocytosed cells is reduced by 26% as a consequence of low filtration rates and intensive production of pseudofaeces. At 20C and 20–50106 cells of Chlamydomonas/l, the maximum amount of algae is sieved out and phagocytosed; the concentration of 10106 cells/l is too low and cannot be compensated for by increased activity of the molluscs. With increasing temperatures, the amount of suspended matter, allowing higher rates of filtration and food utilization, shifts toward higher particle concentrations; but at each temperature a threshold exists, above which increase in particle density is not followed by increase in the amount of particles ingested. Based on theoretical considerations and facts known from literature, 7 different levels of food concentration are distinguishable. Experiments with Chlamydomonas sp. and Dunaliella sp. used as food, reveal the combined influence of particle concentration and particle size on filtration rate. Supplementary experiments with Mytilus edulis resulted in filtration rates similar to those obtained for M. modiolus, whereas, experiments with Cardium edule, Mya arenaria, Mya truncata and Venerupis pullastra revealed low filtration rates. These species, inhabiting waters with high seston contents, seem to be adapted to higher food concentrations, and unable to compensate for low concentrations by higher filtration activities. Adaptation to higher food concentrations makes it possible to ingest large amounts of particles even at low filtration rates. Suspension feeding bivalves are subdivided into four groups on the basis of their different food filtration behaviour.
The interpretation of kinetics of radionuclide accumulation into biological organisms can be performed by using the well-known multicompartment models. The application of a two-compartment model in the interpretation of radionuclide accumulation into marine organisms, when this does not markedly deplete the medium, is considered. It has been found that most of the loss experiments cannot be interpreted without the use of uptake data. The agreement between the uptake and loss parameters is discussed. Explicit expressions for different kinds of two-compartment models are evaluated. The interpretation of irreversible and other special cases is proposed.
Common mussels were collected at 13 stations of the Weser Estuary and the German Bight in 3 size catagories: 14 to 16 mm, 21 to 23 mm, 35 to 40 mm shell length. Equal numbers of the 3 groups from each station were analyzed separately for lead concentration by flameless atomic-absorption spectrophotometry. The lead concentration of the soft parts decreases from 6.4 μg/g dry weight 15 km northwest of Bremerhaven to 1.9 μg/g at Helgoland. At the same station, the concentration in small musels is significantly higher than in larger mussels. The lead concentration is exceptionally high in the kidney, quite high in the intestine (with the digestive glands) and in the adductor muscle, and rather low in the foot, gills, and mantle with gonads. Unpublished results of my laboratory experiments reveal that mussels directly reflect the actual lead concentration of their environment. The observed gradient in lead contents of M. edulis in the Weser Estuary can thus be explained by the dilution of the highly lead-polluted river water by the sea water of the German Bight. With this physiological property, M. elulis is, therefore, highly suitable as an indicator organism for lead, and possibly other heavy metal pollutants.
To study the kinetics of mercury uptake in oysters, adult Crassostrea virginica (Gmelin) were held in seawater containing 10 g mercury/l (ppb) or 100 g mercury/l (ppb), added in the form of mercuric acetate, for 60 days. Mercury concentration in tissues was determined by analysis of individually homogenized oyster meats, using wet digestion and flameless absorption spectrophotometry. After 45 days, average mercury tissue concentration was 140,000 g mercury/kg tissue (ppb) and 28,000 g mercury/kg tissue (ppb) in the 100 ppb and 10 ppb experimental groups, respectively. After this time, concentrations dropped sharply, probably due to spawning. Clearance of mercury from tissue was studied by exposing treated adults to estuarine water (with no additions) for 30 days (100 ppb group) and 160 days (10 ppb group). Tissue concentrations in the 100 ppb mercury environment group declined from 115,000 to 65,000 ppb, and those of the 10 ppb group declined from 18,000 to 15,000 ppb, in 18 days; there-after, no further decline occurred in either group. Oysters accumulated mercury 1,400 times and 2,800 times above the environmental concentrations of 100 and 10 ppb mercury, respectively. Total self-purification was not achieved over a 6 month cleansing period.
In a laboratory experiment, conducted over 130 days, three batches of a total of 100 common mussels, Mytilus edulis, were maintained in media containing different lead concentrations. Two vessels served as controls. There was no acute injury to the mussels; but, over an extended period of time, a marked increase in mortality occurred which was related to the lead concentration in the medium. The median lethal time (LT50) was computed to be 218 days for the control, 150 days with 0.5 mg Pb/l in the medium, 129 days with 1 mg/l, and 105 days with 5 mg/l. Quantitative analyses of the soft parts of M. edulis by flameless atomic-absorption-spectrophotometry revealed a distinct accumulation of lead. From a natural lead content of 8.4 μg Pb/g dry weight, the lead concentration increased to 12,840 μg/g at 0.5 mg/l, to 20,770 μg/g at 1 mg/l and to 39,830 μg/g at 5 mg/l. The ratio of the concentration of lead in the soft parts of M. edulis to the concentration in the medium remained in the same order of magnitude both under laboratory conditions using high lead concentrations and under in situ lead levels. Over a period of 130 days, lead uptake expressed as percentage of lead offered was 10.9% at 0.5 mg/l, 9.5% at 1 mg/l, and 3.4% at 5 mg/l, respectively.
Data, from British Isles coastal waters, on the concentrations of selected metals in sea water and biological indicators, have been obtained by analytical techniques based on atomic absorption spectrophotometry. The results show that there are some areas where significant contamination exists, and the east Irish Sea appears to have the highest concentrations of most metals. However, data in most regions indicate that the concentrations of the metals examined are not significantly higher than those in the open Atlantic Ocean adjacent to the British Isles. The sampling of seaweeds strongly suggests that concentrations of most metals, including those in polluted areas, have changed little over the ten years up to 1970; the concentrations of cadmium may well, on average, have fallen over this period. In the Irish Sea, where the most detailed examination has been made, there is a rapid decrease in sea water concentrations from the shoreline to offshore, and, in general, the proportions of a metal associated with suspended matter remain fairly constant with respect to variations of total concentrations in either time or space.
A technique has been developed for the determination of "soluble" cobalt, copper, iron, lead, nickel and zinc in saline waters by simultaneous extraction of their complexes with ammonium pyrollidine dithiocarbamate (APDC) into methyl isobutyl ketone (MIBK) and subsequent analysis by atomic-absorption spectrophotometry. Particulate matter is analysed separately by dissolving millipore filters in an acetone-hydrochloric acid mixture. Various analytical and instrumental parameters have been evaluated. The method is selfcompensating in that it makes allowance for any incomplete extraction of the complexes. The technique has been applied to the determination of these elements in sea-water and saline lakes.
Heavy metals such as copper, zinc and lead are normal constituents of marine and estuarine environments. When additional quantities are introduced from industrial wastes or sewage they enter the biogeochemical cycle and, as a result of being potentially toxic, may interfere with the ecology of a particular environment. In different marine organisms, the behaviour of heavy metals is described in terms of their absorption, storage, excretion and regulation when different concentrations are available in the environment. At higher concentrations, the detrimental effects of heavy metals become apparent and their different toxic effects and factors affecting them are also described.
121 r = 0.998 ~ '~, 100 "8 ,~" 1 0.1 M. Sehulz-Baldes: Lead Uptake and Loss in Mytilus Mar The effects of heavy metals (other than mercury) on marine and estuarine organisms
- Biol
- G W Bryan
I000 10g y=0.949 log x~-2.121 r = 0.998 ~ '~, 100 "8,~" 1 0.1 M. Sehulz-Baldes: Lead Uptake and Loss in Mytilus Mar. Biol. Bryan, G. W. : The effects of heavy metals (other than mercury) on marine and estuarine organisms. Prec. R. Soc. (Ser. B) 177, 389--410 (1971).
The occurrence of lead in natural waters
- M I Abdullah
- L G Royle
- M. I. Abdullah
Lead. In: Impingement of man on the oceans
- C C Patterson
Lead. In: Impingement of man on the oceans, pp 245?258
- C C Patterson
- C. C. Patterson
Mulawka: Trace metal accumulation by estuarine molluscs
- B H Pringle
- D E Hissong
- E L Katz
- B. H. Pringle
Report of the seminar on methods of detection, measurement and monitoring of pollutants in the marine environment. Rome, 4?
- F.A.O.