A risk‐based protocol to develop acceptable concentrations of bioaccumulative organic chemicals in sediments for the protection of piscivorous wildlife

Abstract

Environmental quality guidelines are benchmarks that indicate whether or not environmental concentrations present measureable risks to ecosystem health. This paper outlines an approach for the development of guidelines for concentrations of bioaccumulative organic chemicals in sediments that would be protective of wildlife at the top of the food chain an aquatic ecosystem. The proposed method uses risk assessment techniques that integrate information on relevant exposure pathways from sediments to top predators and toxicity assessment for avian and mammalian species. The method requires biota‐to‐sediment bioaccumulation factors (BSAFs) for various ecosystems and food webs and knowledge of the predator‐prey relationships and physiological parameters of piscivores. The proposed method is considered to be an improvement to existing regulatory methods for the derivation of water quality guidelines that are based on acute and chronic toxicity data generated primarily from waterborne exposure assays of aquatic species, and recent efforts to develop sediment quality guidelines on the basis of acute and chronic toxicity of contaminated sediments to benthic invertebrates and benthic community structure. Neither of these existing methodologies adequately address the potential for food chain transfer of persistent bioaccumulative organic chemicals through relevant exposure pathways from sediments.

Key Words:

• Acceptable concentration
• sediment accumulation
• piscivorous wildlife
• risk protocol

Notes

Author to whom correspondence should be addressed

Current address: 500–4260 Stillcreek Drive, Burnaby, B.C., V5C 6C6