Sediment Toxicity

Waterfall and riverThe toxicity of sediment-associated phthalates has been investigated in a comprehensive research project 1 carried out at the University of Wisconsin in conjunction with the US EPA. In 10 day sediment toxicity tests with Chironomous tentans and Hyalella azteca no effects were observed for dihexyl, diethylhexyl, diisononyl, 711P and diisodecyl phthalate at the maximum concentration tested (3000 mg/kg dry weight).

These findings are in line with those of two other independent studies. A 28 day chronic sediment toxicity study for both DEHP and DIDP indicated no effects on the time to emergence or sex ratio of the midge (Chironomus riparius) at sediment concentrations up to 10,000 mg/kg dry weight 2. In another study, no effects were observed on moorfrog (Rana arvalis) egg hatching or tadpole survival at the highest sediment concentrations tested i.e. 600 mg/kg dry weight for both DEHP and DIDP 3. It should be noted that these concentrations at which no effects have been observed are orders of magnitude higher than those found in the environment.

References

  1. Call, DJ et al., 1997, "A Laboratory Evaluation of the Toxicity of Sediment-associated Phthalate Esters" Presented at the SETAC 18th Annual Meeting, San Francisco, 16-20 November 1997.
  2. Brown D., Thompson, R S, Stewart, K. M., Croudace, C P and Gillings, E (1996) The effect of phthalate ester plasticisers on the emergence of the midge (Chironomus riparius) from treated sediments. Chemosphere, 32, (17) 2177-2187.
  3. Wennberg, L., Parkman, H, Remberger, M, Viktor, T and Williams, C, Swedish Environmental Institute. Presented at SETAC Europe, Amsterdam, April 1997.