FISH-EMBRYO TOXICITY ASSOCIATED WITH EXPOSURE TO SOILS AND SEDIMENTS CONTAMINATED WITH VARYING CONCENTRATIONS OF DIOXINS AND FURANS

Studies were carried out to evaluate the toxicity to Japanese medaka (Oryzias latipes) embryos after exposure to soils and sediments from various sites contaminated with dioxins and furans. Eggs were exposed to 1-10 mg of material in 1 ml of rearing solution held in a glass vial. The eggs were monitored on a daily basis for death, stage development, and lesions. The soils that were evaluated included two sites from Newark, NJ (2200 and 180 mug/kg 2,3,7,8-TCDD); Times Beach, Missouri (950 mug/kg 2,3,7,8-TCDD); and Seveso, Italy (128 mug/kg 2,3,7,8-TCDD). Exposure to these soils resulted in 100% lethality. Based on the Newark, NJ, soils, the LC50 to post-hatch survival was 0.09 (0.01-9.93) mug/kg of TCDD soil-bound equivalents. Exposure to estuarine core sediments collected near the Newark, NJ, site that contained 0.73-21 mug/kg were also toxic to the embryo, but the toxicity was less in the sediments than in the soil. The estimated bioavailability from the Newark soil was less than 0.2%. This type of biological-based toxicity can be useful in evaluating the extent of clean-up that may be required for any specific site.