Crustaceans bioconcentration

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). 

Two general conclusions may be drawn from the foregoing discussion. First, the interpretation of data from experiments on bioconcentration of xenobiotics should recognize possible complications from the effects of metabolism and excretion, and second that even when aquatic organisms, such as leaches, mussels, or crustaceans that are assumed to display limited metabiolic potential for xenobiotics, are used for monitoring purposes, interpretation of the data should consider the possibility of metabolism and excretion after initial exposure to the toxicant. 

The question then arises of the extent to which any nonlethal effect is reversible after removal of the toxicant. The answer seems to be that in the few cases which have been examined, this may indeed be the case all of them have examined phenolic compounds, one (McCahon et al. 1990) using the crustacean Asellus aquaticus, one assessing respiratory/cardiovascular effects on rainbow trout (Bradbury et al. 1989), and the third (Neilson et al. 1990) using the embryo/larvae assay with zebra fish (Brachydanio rerio). The last of these has been developed into a protocol that is modeled on the standard bioconcentration procedure in which a period of depuration is included after exposure to the toxicant. 

In general, bioconcentration factors decrease for organisms that possess more advanced metabolic systems (Stalling et al. 1973). For example, the mean bioconcentration factors for algae, crustaceans, insects, and fish are 3,399, 662 229, 624 144, and 167 mg/g (wet weight), respectively (Staples et al. 1997). 

Median bioconcentration factor BCF values in aquatic biota exposed to various concentrations of Pb + for 14-140 days varied from about 42 in fish to 2570 in mussels intermediate values were 536 for oysters, 500 for insects, 725 for algae, and 1700 for snails. There are several notable exceptions to this array significantly higher values have been reported in crustacean hepatopancreas, in various species of freshwater invertebrates, in fish bone and liver, and in whole oysters. 

In general, the interactions between xenobiotics and ecosystem constituents are reversible and tend to establish steady states conditioned by the rate-limiting steps. The reversibility applies, of course, only to the interactions at the molecular level, not to the (long-term) impacts on ecosystems. With respect to hazard and risk assessment, parameters regarding the distribution (e.g. bioconcentration and soil sorption), the reactivity (e.g. degradation) and the toxicity (e.g. aquatic species such as fish, crustaceans, algae) are considered. For the description of the chemicals, mostly structurally derived physico-chemical properties are used, among which the most prominent is the 1-octanol/water partition coefficient. The log parameter quanti-... 

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