Acute toxicity data for lower molecular weight phthalate esters for freshwater organisms are abundant, and the various taxonomic groups (protozoa, algae, crustaceans, insects, and fish) are comparable in their sensitivity. Less data are available for marine species, but the available acute data point toward similar sensitivity as for freshwater organisms. Chronic toxicity data for freshwater organisms are available for algae, crustaceans, fish, and amphibians, with differences between taxonomic groups being less than a factor of 30. The limited chronic data for saltwater species again point toward similar sensitivity as for freshwater organisms. In Table 2, an overview is given of the chronic and acute toxicity data of DBP to aquatic organisms. The data presented in Table 2 were used as input for the derivation of maximum permissible concentrations (MPCs) for DBP.
For the higher phthalate esters, no observed effect concentrations (NOECs) exceeding the water solubility are often reported (these values are usually discarded for risk-assessment purposes). Micelle formation and direct physical effects like surface entrapment of the test organisms in layers of the phthalate esters on top of the water column often induce adverse effects at short-term exposure. Such physical effects clearly are not indicative of inherent toxicity. In general, it is found that higher molecular weight phthalates do not exhibit short-term and chronic toxicity to aquatic organisms at concentrations below the aqueous solubility, for the organisms and exposure times tested.
Although elevated levels of phthalates may be measured in sediments, there is no evidence as to the potential or real damage caused to species in the sediment.
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