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In Vitro Assessment of Eight Oil Dispersants for Estrogenic, Androgenic, Anti-androgenic and Cytotoxicity in Cell-Based Assays.
Citation:
WILSON, V. S., P. C. HARTIG, L. E. GRAY, M. C. CARDON, N. WRENCH, C. R. LAMBRIGHT, J. Furr, N. Jeffay, AND B. Hannas. In Vitro Assessment of Eight Oil Dispersants for Estrogenic, Androgenic, Anti-androgenic and Cytotoxicity in Cell-Based Assays. Presented at Society of Environmental Toxicology and Chemistry (SETAC) Meeting, Portland, OR, November 07 - 11, 2010.
Impact/Purpose:
This was research initiated at the request of ORD/ EOC in order to provide some information on the dispersant within tight time constraints. Results showed none of the eight dispersants displayed in vitro estrogenic, androgenic or anti-androgenic activity. All of the dispersants showed cytotoxicity in at least one cell type at concentrations between 10 and 1000 ppm. The results of this work were part of the Internal Report to posted on the EPA web site on June 30, 2010 Background: Large amounts of dispersants have been used on the oil from the Deepwater Horizon spill and concern has arisen about the toxicity of the dispersants including potential endocrine effects due to some dispersant components.
Description:
Large amounts of dispersants have been used on the oil from the Deepwater Horizon spill and concern has arisen about the toxicity of the dispersants. Some of the dispersants reportedly contain nonylphenol ethoxylates which can degrade to estrogenic compounds, thus the potential endocrine effects of the dispersants could be problematic. In order to provide a rapid initial assessment, testing was carried out using well validated in vitro cell-based assays. Dispersants evaluated were Corexit® 9500, Dispersit SPC 1000™, JD 2000™, Nokomis 3-AA, Nokomis 3F4, Saf-Ron Gold, Sea Brat 4 and Zi-400. The goals of this study were two-fold. First, determine if any of eight dispersants displayed estrogenic, androgenic or antiandrogenic activity in vitro using three well validated cell assays. Positive controls and reference compounds with well characterized activities were also evaluated. Secondly, determine the dispersant concentration that induced cytotoxicity in the three cell lines using a quantitative assay of mitochondrial function (MTT) and a subjective assessment by microscopic examination. Nine concentrations of each dispersant from 10,000 ppm to 0.0001 ppm were tested in each assay. Positive controls and reference compound results met all performance criteria in the respective assays. None of the eight dispersants, however, displayed in vitro estrogenic, androgenic or antiandrogenic activity. All of the dispersants showed cytotoxicity in at least one cell type at concentrations between 10 and 1000 ppm. All eight dispersants disrupted cell function and caused cell death in all cell lines in the two highest concentrations (10,000 and 1,000 ppm). Across the in vitro assays, Saf-Ron Gold and JD-2000™ were significantly less toxic (EC50 400 - 2700 ppm), while Dispersit SPC1000™ was most toxic (EC50 7-35 ppm). In vitro toxicity ranking correlated well with recent static acute toxicity studies with inland silverside and mysid shrimp conducted on contract by EPA with the same dispersants ttp://www.epa.gov/bpspill/reports/ComparativeToxTest.Final.6.30.10.pdf). For example, overall Dispersit SPC1000 was most toxic displaying moderate (silverside and cell assays) to slight toxicity (mysid). JD-2000™ was “practically non-toxic” overall (in vitro and in vivo) and Saf-Ron Gold had low toxicity in both mysid and in vitro assays. Toxicity of the other dispersants varied but generally was in the mid or “slightly toxic” range. Disclaimer: Does not necessarily represent EPA policy.