Comparative study of toxicity testing and macroinvertebrate assessment of petroleum storage and manufacturing site and receiving water

Abstract

AbstractToxicity tests were performed on runoff associated with manufacturing activity and effluent from chemical and petroleum storage tank containment areas. Toxicity tests and macroinvertebrate surveys were used to assess the quality of receiving streams. The sensitivity of Ceriodaphnia dubia and Brachionus calyciflorus to these effluents was compared. The 95% confidence limits of the probit LC20 (concentration inversely predicted to kill 20% of test organisms), probit E100 (effect predicted by the probit model at 100% effluent), and linear E100 (effect predicted by a first‐order binomial model at 100% effluent) were used as toxicity criteria and compared, and the results of effluent and receiving water toxicity tests and macroinvertebrate assessments were compared. B. calyciflorus was unaffected by effluents that were toxic to C. dubia. The toxicity criteria generally agreed, but most disagreements involved LC20s with infinite inverse confidence limits, a problem that made the LC20 impractical. Even though discharges were frequently toxic, few downstream samples were toxic, and macroinvertebrate assessments failed to detect impact at most stations. Sensitivity of macroinvertebrate assessments was adversely affected by land development around the study sites. The macroinver‐tebrate indices were difficult to interpret because their variances were not known.