Toxicity in Aquatic Organisms

Deneer (2000) reviewed acute toxicity in aquatic organisms for about 200 pesticide mixtures with diverse modes of action. He found that combined toxicity in 90% of the cases differed from concentration additivity within a factor of 2. Two large studies on the chronic toxicity of binary pesticide mixtures (Faust et al. 1994 Altenburger et al. 1996) demonstrated that, in most cases (> 60%), the best fit of observed mixture effects was to the concentration addition model. 

There are a variety of methods that can be used to examine population genetic structure. In Figure 3, methods for evaluating population-level effects of toxicants in aquatic organisms have been categorized... 

Mammals and birds vary in their sensitivity to warfarin. Horses are resistant to the coumarins and cats are more sensitive than dogs. Signs of toxicity in animals include anorexia, weakness, vomiting, diarrhea, bleeding, and dyspnea. Toxic effects can be monitored by measurement of the prothrombin time (PT) or one-stage PT. Treatment is as for humans. The recommended dose of vitamin K for dogs and cats is 0.25-1 mg kg day for 5-14 days. There is minimal to no toxicity in aquatic organisms. 

Toxicity in Aquatic Organisms A survey of the data available on aquatic life shows that significant effects on the growth and reproduction of phyto- and zooplank-tonic organisms have been obtained with TBT concentrations [Pg.1121]

TOXICITY high acute and chronic toxicity in aquatic organisms... 

The 2006 Frequent Questions include the following parameters describing when data on acute and chronic toxicity in aquatic organisms must be reported ... 

Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment... 

Data sets on toxicity to aquatic organisms vary considerably from compound to compound, with dibutyltin being the best studied. Results of toxicity tests for all compounds are summarized in Figure 2. Values for all but one test on the octyltins have been set at the solubility of the compounds, since no toxicity was observed below the solubilities derivation of PNECs for the octyltins are, therefore, more precautionary than for the other compounds. 

Hirose A, Takagi A, Nishimura T, Ema M (2004) Review of reproductive and developmentai toxicity induced by organotins in aquatic organisms and experimentai animais. Organohalogen Compounds, 66 3042-3047. 

Nickel is toxic to aquatic organisms at levels typically observed in POTW (publicly owned treatment works) effluents ... 

Chromium can exist as either trivalent or hexavalent compounds in raw wastewater streams. The chromium that passes through the POTW is discharged to ambient surface water. Chromium is toxic to aquatic organisms at levels observed in POTW effluents15 ... 

Conventional WWTPs are, therefore, unable to remove wide ranges of pharmaceuticals and other compounds. For pharmaceuticals, although acute toxicity of aquatic organisms or chronic effects are unlikely with the present concentrations due to dilution effects, a wide range of pharmaceuticals are detected in the Ebro, and the overall toxicity of mixed pharmaceuticals may be high. Further studies are therefore required to assess the interactions of different compounds and the consequential health effects. In a similar manner to other pollutants, pharmaceuticals have a clear sensitivity to climate change through dilution effects, and the projected future decrease in annual precipitation could cause certain compound concentrations (e.g. anti-inflammatory diclofenac and p-blocker pranolol) to reach levels which may cause chronic effects [76]. 

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). 

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