Comparative toxicity of Corexit� 7664 to the early life stages of four marine species

Abstract

Abstract. The toxicity of the oil dispersing agent Corexit ® 7664 was evaluated using the early life stages of four California marine species: the red abalone (Haliotis rufescens), the topsmelt (Atherinops affinis), a mysid (Holmesimysis costata), and the giant kelp (Macrocystispyrifera). Spiked-exposure, continuous-flow toxicity tests of 48-96 h were performed in triplicate in closed test chambers. Dispersant concentrations were measured by UV spectrophotometry. In terms of median-effect concentration, the order of test sensitivity was Haliotis > Atherinops > Holmesimysis > Macrocystis. NOEC data also showed Haliotis tests to be the most sensitive, with Macrocystis tests having similar values, followed by Atherinops and Holmesimysis tests, respectively. Toxicity of Corexit ® 7664 was compared to that of Corexit ® 9527, and the latter was found to be more toxic to all four species; interspecific rankings were similar for the two agents.At the time of the 1967 Torrey Canyon spill, oil dispersing agents were mainly used to clean tanker holds, bilges, and so forth, and were generally based on aromatic hydrocarbon solvents such as kerosene (National Research Council 1989). One of the main realizations to come from the ecological disaster of the Torrey Canyon incident was that these mostly solvent-based spill removers were highly toxic in and of themselves and thus were not acceptable for further use in the environment (Smith 1968). In response, a second generation of dispersants were formulated that relied more heavily on less toxic constituents, such as aliphatic hydrocarbon solvents, nonionic surfactants, and water. Corexit ® 7664 was one of the first of these to be marketed.As part of an ongoing evaluation of the toxicity of oil dispersants licensed for use in California, the effects of Corexit ® 7664 on the early life stages of four indigenous nearshore marineCorrespondence to: M. M. Singer species were investigated. The four--the red abalone (Haliotis rufescens), a kelp forest mysid (Holmesimysis costata), the topsmelt (Atherinops affinis), and the giant kelp (Macrocystis pyrifera)--represent a wide taxonomic and trophic range and are economically and/or ecologically important (Singer et al. 1990a). This suite of tests utilizes the early life stages of each of these species. However, the endpoints vary: two are sublethal and two are lethal.Since effective dispersant use at sea is predicated on sufficient environmental mixing energy (in the form of wind, swell), the use of spiked exposures allows for a more realistic modeling of field exposure conditions (Singer et al. 1991).Toxicity testing followed previously established procedures for flow-through, spiked-exposure dispersant testing (Singer et al.

Comparison of Acute Aquatic Effects of the Oil Dispersant Corexit 9500 with Those of Other Corexit Series Dispersants

“…The present data have indicated the Haliotis test to be significantly more sensitive than the Holmesimysis test; this is consistent with all past results (Singer et al, 1991(Singer et al, , 1993(Singer et al, , 1994(Singer et al, , 1995. These differences in sensitivity are likely the result of life stage and/or test endpoint differences.…”

“…Biological acceptability criteria followed those of established test protocols; generally, <20% effect in controls was deemed acceptable. Chemical acceptability criteria were established in earlier spiked-exposure testing (Singer et al, 1991(Singer et al, , 1993(Singer et al, , 1994; similarity of chemical concentration decline rates both within and among tests was essential to establish that all tests modeled similar conditions. Linear regressions of log-transformed concentrations versus time for all treatments within a test were compared by analysis of covari- …”

The acute toxicity of chemically and physically dispersed crude oil to key arctic species under arctic conditions during the open water season

“…The facts that chemically dispersed petroleum produced less toxicity per unit of measured TPH concentration and the calculated concentration of the dispersant in the mixture was at least 20-fold lower than the effects level indicates that the dispersant did not contribute to the acute toxicity of CEWAF. This finding is consistent with studies conducted with temperate mysids and fish [3,5] and the mullet, Liza ramada [71]. Dispersant concentrations in the field have been estimated to be 0.030 mg/L immediately following application [72].…”

“…Acute toxicity experiments followed laboratory protocols adapted from the Chemical Response to Oil Spills Ecologic Research Forum (CROSERF) with modifications to better represent ice‐free conditions of the Beaufort and Chukchi Seas . Modifications incorporated in this testing program included: 1) test species that are representative of arctic food webs at age classes representative of ice‐free period; 2) Beaufort/Chukchi Sea seawater at temperatures representative of ice free‐period (−1 °C to 5 °C); 3) oil‐to‐water and dispersant‐to‐oil loading rates representative of potential field conditions; 4) use of spiked exposures simulating changes in exposure concentrations that occur in a real‐world oil discharge; 5) use of extended test duration to ensure an accurate assessment of acute toxicity responses by arctic species to spiked exposures; and 6) comprehensive analytical characterization of WAFs to quantify exposure concentrations including TPHs, and total polynuclear aromatic hydrocarbons (parent and alkylated compounds) for every test.…”

Efeitos tóxicos de surfactantes fitossanitários para o peixe mato grosso (Hyphessobrycon eques)

“…Pela utilização em diversos setores agroindustrial e doméstico, vários trabalhos foram realizados para se avaliar a toxicidade dos surfactantes nos organismos aquáticos (MACEK;KRZEMINSKI, 1975;FOGELS;SPRAGUE, 1977;SINGER et al, 1994SINGER et al, , 1995GULEC;HOLDWAY, 2000;BUHL;HAMILTON, 2000;KROGH et al, 2003;ROCHA et al, 2007;TENEYCKE;MARKEE, 2007).…”