Results of Toxicity Identification Evaluations (TIE`S) conducted on the A-01 outfall and its contributory waste streams, July 1996--February 1997

摘要

Toxicity tests were conducted at nine locations during the summer of 1996. The results indicated that A-01B, A-01C, A-03, A-04, A-05 and A-01 were toxic to the test species, Ceriodaphnia dubia, while A-01A, A-06, and WE-01 were not toxic. Beginning in August 1996, Toxicity Identification Evaluations (TIE`s) were initiated on all toxic outfalls in order to identify the toxicants responsible for the observed toxicity. A complete TIE was performed on A-01 because it is the regulatory compliance point for all of the combined waste streams that were tested. Only the portions of a TIE that are related to metal and chlorine toxicity were performed on the remaining locations because existing data indicated that metals and chlorine were present in potentially toxic quantities at these locations, and there was no evidence that other toxicants would be expected to be present in toxic amounts. The results of the TIE`s indicate that metals are responsible for most of the toxicity at all of the outfalls that were toxic and that chlorine contributed to the toxicity at two of the outfalls. Specifically, the toxicity at A-01B, A-01C, and A-01 was due to copper; the toxicity at A-03 was due to primarily to copper, although zinc also contributed to the toxicity; the toxicity at A-04 was due primarily to copper, with residual chlorine and zinc contributing to the toxicity; and the toxicity at A-05 was due primarily to copper, with residual chlorine contributing to the toxicity. A-03 was the most toxic outfall, with 100% mortality occurring at concentrations as low as 12.5% effluent. A-03 was found to have concentrations of copper, lead, and zinc that exceeded EPA water quality criteria by approximately two orders of magnitude. The metal concentrations at A-01 and WE-01, which is located approximately 0.5 miles downstream from A-01 were similar. However, A-01 was toxic, while WE-01 was not.