Abstract |
The site was used to manufacture specialty intermediate chemicals for the producers of dyes, pharmaceuticals, cosmetics, herbicides, and pesticides. The herbicide Fenac (2,3,6-trichlorophenylacetic acid) is a major on- and off-site contaminant. One-hundred-twenty-eight soils were collected. Elutriates were prepared for toxicity evaluation of water extractable constituents. The chemical nature of the elutriates was so complex that it was impossible to determine chemical cause/biological effect relationships based on chemical analyses alone. Bioassays identified locations of toxicity on the site without identifying the causative agents; important because numerical criteria are not available for many organic chemicals and there is little understanding of the affects of mixtures of chemicals in complex wastes on test organisms or the environment. The measured response represents an actual assessment of any synergistic or antagonistic interactions. Fifty-nine percent of the 128 elutriates were toxic to the algae Selenastrum capricornutum and 43 percent were toxic to Daphnia magna. Both organisms indicated that toxic sample numbers increased with depth of sampling. The Toxi-chromotest (bacteria) revealed toxicity in 2.3% of the 128 elutriates; all had been identified by algae and Daphnia. Ten elutriates were toxic only to Daphnia and 30 only to S. capricornutum. Fifty-one were toxic to both algae and Daphnia, but Daphnia was most sensitive in only 8 elutriates. If one test was used, 10 to 30 toxic elutriates would have not been identified, depending on the test organism selected. |