Coral Toxicity Research for Determining Thresholds for Dispersant Use NEBA Calculations

The use of dispersants in close proximity to coral communities is generally not recommended, although Net Environmental Benefit Analysis (NEBA) of various response methods and priorities may override this principle. The NEBA calculation for use of dispersants near corals is a function of the relative effects of dissolved components of crude oil (alone) and components of chemically enhanced (dispersed) oil in the water column on corals. This is best determined by examining the toxicity (concentration and duration of exposure) of oil and dispersed oil to corals at the individual/organism and cellular levels. Unfortunately, this is a little studied area and very little coral toxicity information exists.

This paper describes ongoing multi-year research being conducted at Nova Southeastern University Oceanographic Center to fill the coral toxicity information gap and determine toxicity thresholds for individual corals. The research program was designed with inputs from an oversight committee and a broad group of collaborators from the response industry and toxicology communities. The output of the of the study is intended to be compatible with current and emerging predictive models such as NOAA’s Chemical Aquatic Fate and Effects (CAFÉ) database, which is used to estimate the fate and effects of thousands of chemicals, oils, and dispersants. An overview of previous and current research on hydrocarbon toxicity to corals will be presented, along with proposed guidelines for effective toxicity testing which conforms to standardized protocols and aids in comparison of results between studies and extrapolation to actual spills.