Assessment of toxicity of two types of drill cuttings from a drilling rig on the Trinidad East coast using Metamysidopsis insularis |
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| Authors: | Aaron Balgobin Azeena Ali Kalim Shah Natasha Ramroop Singh |
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| Institution: | 1. Department of Biomedical Engineering , University of Trinidad and Tobago , O’Meara , Trinidad and Tobago aaron.balgobin@utt.edu.tt;3. Department of Energy Systems and Petroleum , University of Trinidad and Tobago , O’Meara , Trinidad and Tobago;4. Faculty of Environmental Studies , York University , Toronto , ON , Canada;5. Department of Biomedical Engineering , University of Trinidad and Tobago , O’Meara , Trinidad and Tobago |
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| Abstract: | This study investigated the relative toxicity of water-based cuttings (WBC) and synthetic oil-based cuttings (SOBC) to the marine species, Metamysidopsis insularis. Results obtained indicate that SOBC (LC50 1.2 (0.85–1.6)%) was more toxic to M. insularis than WBC (LC50 9.9 (8.3–11.8)%), with similar metal contents in both types of cuttings. The elevated levels of metals found in the cuttings when compared to surficial sediments may be due to both drilling fluids, as well as the rock strata from which the cuttings were obtained. Furthermore, total petroleum hydrocarbon (TPH) analyses demonstrated significantly higher concentrations of TPH present in SOBC (14,680?±?1250?mg?kg?1) compared to WBC (860?±?115?mg?kg?1). This may also be due to the increased depth and hence oil bearing rock formations in the selected sampling area, along with the associated synthetic oil-based drilling fluid. These findings therefore supply evidence that drill cuttings after treatment prior to discharge are potentially toxic to marine organisms. |
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| Keywords: | cuttings metals toxicity offshore drilling hydrocarbons |
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