Aquatic Organisms Marine

Sublethal effects of chromium are reported for representative species of marine organisms, including algae and higher plants, mollusks, nematodes, crustaceans, annelids, echinoderms, fishes, birds, and mammals. 

Algae and higher plants accumulated chromium from seawater by factors up to 8600, 

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Toxicology LD50 (oral, rat) 191 mg/kg, (dermal, rabbit) 983 mg/kg corrosive to eyes, skin, mucous membranes toxic, corrosive by ing. causes burns may be absorbed thru skin in sufficient amount to cause systemic toxicity inh. may cause sore throat, coughing, shortness of breath, nasal irritation Environmental LC50 (zebra fish, 48 h) 0.32 mg/l toxic to aquatic organisms marine pollutant biodeg. 

Fig. 7. Toxicity of chlorine to aquatic organisms, (a) Time-dependent mortaUty (50%) of four example species in various levels of total residual chlorine in the laboratory, where for A, A.losa aestivalis and B, Salmogairdnerii r (correlation coefficient of the curve) = —0.96 and for C, P/euroneetesplatessa and D, Salmo trutta r = —0.98. (b) A summary of chlorine toxicity to freshwater species, indicating overall no-effect thresholds for acute and chronic exposures. Numbers indicate where more than one test yielded the same result. A different summary figure appHes to marine organisms because of differences in the...

Environmental problems associated with PCBs are the result of a number of factors. Several open uses of PCBs have resulted in thein direct introduction into the environment, eg, organic diluents careless PCB disposal practices have resulted in significant releases into aquatic and marine ecosystems higher chlorinated PCBs are very stable in thein persistence in different environmental matrices and by a variety of processes (Fig. 1) PCBs are transported throughout the global ecosystem and preferentiaHy bioconcentrate in higher trophic levels of the food chain. 

Waterborne solutions of zinc-cadmium mixtures were usually additive in toxicity to aquatic organisms, including freshwater fishes (Skidmore 1964) and amphipods (de March 1988), and to marine fishes (Eisler and Gardner 1973), copepods (Verriopoulos and Dimas 1988), and amphipods (Ahsanullah et al. 1988). However, mixtures of zinc and cadmium were less toxic than expected to Daphnia magna, as judged by acute lethality studies (Attar and Maly 1982). 

In acute toxicity tests with aquatic organisms, LC50 (96 h) values — with only one exception — exceeded 130 pg/L. The exception was the larva of a marine crab with an LC50 (96 h) value of... 

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