Assessing toxicities of hydrophobic organic pollutants in Huaihe River by using two types of sampling.

Hydrophobic organic pollutants in water from the Huaihe River were extracted by solid phase extraction and sequestered by semipermeable membrane device (SPMD), and those in sediments were extracted by organic solvent. Combined with chemical analysis, Lumistox test and ethoxyresorfin O-deethylase (EROD) assay were carried out for assessing the acute toxicities and the Ah-receptor-related toxic effects of the trace hydrophobic organic pollutants in this aquatic environment. The acute toxicants in water and sediment of the Huaihe River included substituted benzenes and pesticides, mainly 2,4,6-trichlorophenol, atrazine, hexachlorobenzene, and nitrobenzenes as well as persistent EROD inducers or Ah-agonists, including PAHs and PCBs, were determined. The highest acute toxicant concentration occurred at the center of the river (H3), while highest chronic toxicants occurred at upstream (H1). At downstream (H4), the EROD inducers in sediment depicted more persistency. The results also showed that the sampling procedures for waters have significant influences on the results of bioassays. Bioassay for acute toxicants in water using SPE was unable to obtain important information. However, bioassays for sediment extracts and SPMD concentrates showed similar pattern of toxic variation among different locations.