Testing of the EPA Toxicity Identification Evaluation Protocol in the Textile Dye Manufacturing Industry

Abstract

The case study for evaluating the EPA Toxicity Identification Evaluation protocol was a textile dye manufacturing plant that suspected chloride as the major source of toxicity. Phase I of the protocol, together with some additional experiments, was successful in showing that one-third to one-half of the toxicity was due to chloride and the rest was due to nonpolar organic compounds. From 41 to 78 organic chemicals were found in toxic fractions using the EPA Phase II test procedures; these included dyes, dye intermediates, process chemicals such as surfactants and possibly metabolic by-products of waste treatment. A major component of Surfynol, a widely used surfactant, was present in concentrations much higher than any other chemical in the toxic fractions of all three samples analyzed. However, the concentration was still considerably less than the LC50 (mg/L) and thus could not explain whole effluent toxicity. Instead, more than one organic chemical may be involved.