Toxicity of an oil dispersant to the early life stages of four California marine species

Aquatic toxicity considerations are part of the net environmental benefit analysis and approval decision process on the use of dispersants in the event of an offshore oil spill. Substantial information is available on the acute toxicity of physically and chemically dispersed oil to a diverse subset of aquatic species generated under controlled laboratory conditions. However, most information has been generated following standard laboratory practices, which do not realistically represent oil spill conditions in the field. The goal of the present quantitative review is to evaluate the use of standard toxicity testing data to help inform decisions regarding dispersant use, recognizing some key issues with current practices, specifically, reporting toxicity metrics (nominal vs measured), exposure duration (standard durations vs short-term exposures), and exposure concentrations (constant vs spiked). Analytical chemistry data also were used to demonstrate the role of oil loading on acute toxicity and the influence of dispersants on chemical partitioning. The analyses presented here strongly suggest that decisions should be made, at a minimum, based on measured aqueous exposure concentrations and, ideally, using data from short-term exposure durations under spiked exposure concentrations. Available data sets are used to demonstrate how species sensitivity distribution curves can provide useful insights to the decision-making process on dispersant use. Finally, recommendations are provided, including the adoption of oil spill-appropriate toxicity testing practices. Environ Toxicol Chem 2014;33:732-742. # 2014 SETAC

Section: The Use Of Toxicity Data In Decision Makingmentioning

confidence: 99%

Issues and challenges with oil toxicity data and implications for their use in decision making: A quantitative review

Bejarano¹,

Clark²,

Coelho³

2014

Laboratory spawning of topsmelt, Atherinops affinis, with notes on culture and growth of larvae

Middaugh

Hemmer

Anderson

1992

Topsmelt (Atherinops affinis) were spawned repeatedly in the laboratory from May to July 1989. A periodic “temperature spike” from the holding temperature of approximately 18 up to approximately 20.5°C, introduced at 7‐ to 9‐d intervals, resulted in maximum production of viable embryos on the fourth morning after the spike. Examination of embryonic stages and comparison to known developmental rates for Atherinops affinis embryos revealed that spawning was generally nocturnal, occurring between 1900 and 0500 h. Survival of embryonic and larval Atherinops affinis cultured at 21 ± 1°C and 20 ± 2‰ salinity was excellent (>80%). A larval growth curve was developed for the first 24 d post‐hatch.

Off‐season spawning and factors influencing toxicity test development with topsmelt Atherinops Affinis

Anderson

Hunt

McNulty

et al. 1994

Three separate groups of adult topsmelt (Atherinops a/finis) were spawned in rotation in laboratory culture over a two‐year period to provide larvae for toxicity tests. Size and viability of embryos and larvae produced during the normal summer spawning period (May‐August) were compared to those produced during the off season (October‐April). Mean embryo viability was relatively high throughout the study (82%), whereas size of larvae varied. Larval size was significantly larger during the summer spawning period than in winter. A 7‐d growth and survival toxicity test protocol was developed for topsmelt larvae. Variability of the protocol was assessed over a 12‐month period using copper chloride as a reference toxicant. Precision of 12 toxicity tests using copper was high; the intralaboratory C.V. for copper LC50s was 19%. The 7‐d larval protocol also gave comparable results in two interlaboratory toxicity tests using copper and complex effluent. This study demonstrates that topsmelt may be spawned throughout the year to provide larvae for toxicity tests and that topsmelt larvae have comparable sensitivity to other larval fishes commonly used in toxicity testing.