Mollusks bioaccumulation

PAHs can be bioconcentrated or bioaccumulated by certain aquatic invertebrates low in the food chain that lack the capacity for effective biotransformation (Walker and Livingstone 1992). Mollusks and Daphnia spp. are examples of organisms that readily bioconcentrate PAH. On the other hand, fish and other aquatic vertebrates readily biotransform PAH so, biomagnification does not extend up the food chain as it does in the case of persistent polychlorinated compounds. As noted earlier, P450-based monooxygenases are not well represented in mollusks and many other aquatic invertebrates (see Chapter 4, Section 4.2) so, this observation is not surprising. Oxidation catalyzed by P450 is the principal (perhaps the only) effective mechanism of primary metabolism of PAH. 

Examples of differences in the responses of wildlife organisms to EDCs include the differences in sensitivity to phthalates and bisphenols among mollusks, crustaceans, and amphibians compared to fish. In invertebrates, biological effects are observed at exposures in the ng/L to low pg/L range, compared to high pg/L for most effects in fish (reviewed in Oehtmann et al. 2008). In addition, aquatic mollusks tend to bioconcentrate and bioaccumulate pollutants to a greater level than hsh, possibly owing to poorer capabilities for metabolic detoxification (see Chapter 4, Section 4.3). 

Van der Oost, R., H. Heida, and A. Opperhuizen. 1988. Polychlorinated biphenyl congeners in sediments, plankton, mollusks, crustaceans, and eel in a freshwater lake implications of using reference chemicals and indicator organisms in bioaccumulation studies. Arch. Environ. Contam. Toxicol. 17 721-729. 

Aqueous and sedimentary TBT and TFT cause chronic and acute effects in algae, zooplankton, Crustacea, mollusks, fish, and animals. These effects have been local in nature, occurring mostly in harbors near industrialized lands. TBT is bioaccumulated in many species, which is unfortunate as it is a potent endocrine disrupter. The enrichment factor in mussels, snails, and oysters ranges from 10,000 to 60,000. As mentioned in Section 28.7.1, TBT induces imposex in marine gastropods. 

Maintenance of bottom fish and marine mollusk communities. Bioaccumulation in the marine food chain will not result in unacceptable tissue COPC concentrations. Measure COPC concentrations in tissue samples and compare to literature-based toxicity reference values. 

BIOACCUMULATION BCF (5 aquatic mollusks) 350 500 BCF (golden orfe) 3890 BCF (fish) 10715 BCF (algae Chlorella fusca) 12260 bioconcentration is significant... 

Plutonium was found to bioaccumulate in aquatic organisms, primarily at the lower end of the food chain. The bioconcentration factors (i.e., the amount of the chemical found in the organism divided by the concentration in the surrounding water over the same time period) were 1,000 for mollusks and algae, 100 for Crustacea, and 10 for fish (WHO 1983). Plutonium is concentrated in the bones of fish rather than in muscle tissues, as seen by whole fish to muscle tissue ratios of 2X10 to 5x10 or 40 1 (NCRP 1984). 

Pentachlorophenol was found at high concentrations in all samples of sediments, waters, and biota collected near industrial facilities that used PCP as a wood preservative. Fish can bioconcentrate PCP from water up to 10,000 times. However, similar concentrations were measured in the common mussel, Mytilus edulis, and the softshell clam, Mya arenaria, from the vicinity of PCP-contaminated wastewater discharges as well as from more distant collection sites thus, PCP bioaccumulation in marine bivalve mollusks does not appear to be dose related. 

The accumulation of in fish and invertebrates such as mollusks and Crustacea, over the short-term, can result from the release of in liquid effluents. Fish and invertebrates in equilibrium with fresh water containing 1 pCi L would be expected to contain approximately 15 and 5 pCi kg respectively, based on calculated bioaccumulation factors for iodine (Thompson et al, 1972). Fish taken from salt water of the same concentration would be expected to contain 10-20 pCi kg and invertebrates 50-100 pCi kg (Frecke, 1967 Thompson et al, 1972). The intake of with fresh water fish having a normalized concentration of 15 pCi kg" per pCi L water were calculated from the data in Table 4.3 on fish consumption by the four age groups. The results indicate that such fish would contribute 0.05, 0.08, 0.15, and 0.21 pCi to the daily diets of the 1-, 4-, and 14-year olds and adults, respectively. These intakes are insignificant compared to corresponding intakes with drinking water obtained from the same source as the fish. 

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