AQUATIC HAZARD ASSESSMENT OF THE TOXIC FRACTION FROM THE EFFLUENT OF A PETROCHEMICAL PLANT

Effluent hazard assessment guidelines were applied to determine the environmental safety of discharged chloroether fractions from a chemical plant effluent. The chloroether fraction was identified as a mixture of pentachloroethers (2,5,6-trichlorohexyl 1',3'-dichloroisopropyl ether [PCE 1,3] and 2,5,6-trichlorohexyl 2',3'-dichloropropyl ether [PCE 2,3]), tetrachloropropyl ethers (TCPE; a mixture of 1,3,1'3'-tetrachloroisopropyl ether, 1,3-dichloroisopropyl 2',3'-dichloropropyl ether, and 2,3,2',3'-tetrachloropropyl ether), 1,2,5,6 tetrachlorohexane (TCH), and related components. The fractions were identified in a toxicity identification evaluation (TIE). The chloroether mixture was acutely toxic between 1.5 and 20 mg/L and had no observed effect concentrations (NOEC) for chronic toxicity from 1 to 3.2 mg/L. Individual chloroether components showed acute toxicity (LC50) from 1.5 to 56 mg/L. Acute toxicity predictions from U.S. Environmental Protection Agency (U.S. EPA) structure-activity relationships (SAR) were within a factor of four. Acute to chronic ratios for specific chloroether components were between 3 and 14. Sediment studies showed moderate sorption of TCPE with a log K(oc) between 2.7 and 2.9. The log K(ow) was 3.2 for TCPE, and the bioconcentration potential (log BCF) for the mixture was < 2.7. Laboratory and field stream experiments confirmed laboratory predictions for toxicity, with NOEC for trout growth > 0.26 mg/L and effects on Gammarus feeding at 0.44 mg/L of the mixture.