Sediment pore water toxicity testing

The toxicity of the pore water from the sediments of nine fresh water systems in and around Amsterdam City was studied with the aid of four acute toxicity tests. Based on preliminary chemical analysis, the sediments of three of the tested systems had to be considered strongly contaminated, according to the quality standards derived from the Dutch Law on Soil Pollution Control. In addition, the acute toxicity of groundwater from a heavily contaminated industrial building site was also examined. The following toxicity tests were used. 1. Microtox bioluminescence assay, or Microtox test. This test is based on the inhibition of bioluminescence of Photobacterium phosphoreum; 2. Rotoxkit F, based on the LC(50) of Brachionus calyciflorus; 3. Thamnotoxkit F, based on the LC(50) of Thamnocephalus plaxyurus; 4. Toxichromotest, based on the inhibition of beta-galactosidase formation in Escherichia coli, The objective of the study was to test the feasibility of the toxicity tests as a tool for the risk evaluation of contaminated sites, both in water and on land. The results indicated that the sediments of three of the eight sites studied could be classified as toxic and one site even as very toxic. The outcome of the toxicity testing confirmed the results of the chemical analysis for only one site. It appeared that the Microtox and the Thamnotoxkit F tests were the most sensitive acute toxicity tests. It could be concluded that the resolution of the toxicity tests scrutinized was insufficient to reliably discriminate the environmental quality of the sediments at the locations studied. The bioassays, however, are useful in determining remediation priorities of contaminated sites. Copyright (C) 1996 IAWQ.