PW02 Wildlife as Ecological Receptors at Hazardous Waste Sites
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW044) Assessing the Risks to Carnivorous Fish in the Calcasieu Estuary, Louisiana: A Probabilistic Risk Assessment.
Teed, R1, Moore, D1, MacDonald, D2, MacDonald, D1, Breton, R1, Pawlisz, A1, Thompson, R1, 1 The Cadmus Group, Inc., Ottawa, Ontario, Canada2 MacDonald Environmental Sciences Ltd., Nanaimo, British Columbia, Canada
ABSTRACT- Development and industrialization in and around the Calcasieu Estuary in southwestern Louisiana in recent decades has led to environmental contamination in the area. An ecological risk assessment (ERA) was conducted to determine the risks posed by contaminants at this site to carnivorous fish. A conservative, deterministic ERA was carried out to identify areas of concern (AOCs) and chemicals of concern (COCs) in the Calcasieu Estuary. The only COC identified for carnivorous fish was total polychlorinated biphenyls (tPCBs) in the Bayou D Inde, Middle Calcasieu River, and Upper Calcasieu River AOCs. A probabilistic ERA was then conducted for each COC-AOC-receptor combination. Four focal species were selected for the assessment. They included spotted seatrout (Cynoscion nebulosus), black drum (Pogonias cromis), red drum (Sciaenops ocellatus), and southern flounder (Paralichthys lethostigma). The ERA approach was to determine whether levels of PCBs in the tissues of carnivorous fish in the Calcasieu Estuary were higher than the tissue residue benchmark values for survival, growth, and reproduction, and to determine the probabilities of effects of differing magnitude to these effect endpoints. Exposure of carnivorous fish to tPCBs was determined by measuring whole body burdens in the four focal species. The effects characterization involved a review of the scientific literature for data and information on the effects of tPCB body burdens to carnivorous fish, and selecting the appropriate effects metrics. Lognormal distributions were fit to the tissue residue data for each AOC using the maximum likelihood estimation method. The distributions were used to estimate the probabilities of exceeding the lower and upper bounds of the tissue residue value (TRV) range. For all AOCs, the probability of exceeding the lower or upper TRV was zero or close to it. Therefore the risk of tPCBs adversely impacting carnivorous fish in the areas of concern is low.
Key words: wildlife, risk assessment, fish, contaminated site