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(P252) Discerning toxic fractions of crankcase oil and diagnostic responses of freshwater testing organisms.
Mastin, Brian*,1, Rodgers, John1, 1 Clemson University, Pendleton, SC, USA
ABSTRACT- Crankcase oil is a complex mixture of aliphatic and aromatic hydrocarbons, metals, detergents, dispersants, antiwear additives, and antioxidants that may contribute to the toxicity of the oil in water. Crankcase oil enters aquatic receiving systems in stormwater runoff from industrial facilities, parking structures, and roadways or is accidentally or incidentally disposed onto the ground and into landfills. In this study, we measured the potency of new crankcase oil to Ceriodaphnia dubia, Pimephales promelas, and Raphidocelis subcapitata, discerned toxic fractions using relevant Toxicity Identification Evaluation (TIE) manipulations, and identified diagnostic responses of these sentinel species that may be useful for site assessment and mitigation design. C. dubia was the most sensitive aquatic organism tested with a 7-d LC50 of 50 mg crankcase oil/L and an exposure-response slope of 1.81% mortality/mg crankcase oil/L. The mean 96-h IC50 for R. subcapitata total chlorophyll concentration and 7-d LC50 for P. promelas were 125 and 352 mg crankcase oil/L, respectively. Addition of the metal chelating agent EDTA increased C. dubia and P. promelas survival from 0 to >50% and ≥80%, respectively in the 1240 mg crankcase oil/L test solution. From TIE manipulations that simulated volatilization, sorption, and biodegradation, classes of organic materials that elicited toxicity for C. dubia and P. promelas were identified. TIE procedures, bioassays, and chemical analyses were used together as diagnostic tools to describe the toxic fraction(s) of this complex mixture (toxicity identification fingerprint). This toxicity identification approach can also be applied to determine treatment or remediation tactics that may be combined into a strategy to remove oil and ameliorate toxicity from oil-contaminated sources such as stormwater runoff or produced waters.
Key words: crankcase oil, potency, biodirected analysis, toxicity identification evaluations
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