GeoPro Talks – Compilation and Evaluation of Fish-Specific Toxicity Reference Values (TRVs) for the Federal Contaminated Sites Action Plan (FCSAP)

June 10th, 2022 by

Fish are an important receptor group ecologically and socioeconomically, and are often of key interest in aquatic ecological risk assessments (ERAs) at contaminated sites. Toxicity reference values (TRVs) are one tool used in ERAs as benchmarks of effects against which environmental exposure to contaminants can be compared. A new ERA Guidance Module for the Canadian Federal Contaminated Sites Action Plan (FCSAP) is in development which focuses on TRVs for fish. This new Module builds on existing FCSAP ERA guidance for selecting and developing site-specific TRVs (Module 2), and for recommended default TRVs for protection of avian and mammalian wildlife (Module 7). In contrast to wildlife TRVs, which are readily available from commonly referenced sources, standard compilations of TRVs for the protection of fish are not available to our knowledge. Therefore, to assess risk to fish, commonly relied-upon tools include (1) more generic ‘benchmarks’ such as aquatic life guidelines, which are not specific to fish, and (2) more involved field-based lines of evidence such as toxicity testing and population surveys. This project suggests fish-specific TRVs that would be suitable default values for use at FCSAP sites. Suggested default fish specific TRVs were identified through a systematic process of evaluating fish-specific TRVs that were available from the scientific literature, as well as evaluating the dataset underlying existing water quality guidelines (WQGs) from Canadian and Federal Environmental Quality Guidelines (CEQGs and FEQGs) and from USEPA. A set of evaluation criteria (similar to those used for selecting default wildlife TRVs for FCSAP’s ERA Guidance Module 7) were used to identify each possible TRV’s merits, limitations and uncertainties. The new Module suggests default water-concentration, dietary tissue concentration, and fish tissue concentration-based TRVs for evaluation of fish for a number of metals and organic contaminants. For cases where existing water quality guidelines were suggested as suitable default water concentration-based TRVs, suggestions were provided on how to further develop or refine those guidelines to be more fish-specific. Some practical approaches to developing fish-specific TRVs are illustrated with examples for a few metals (arsenic, cadmium, cobalt, uranium, zinc) and readily available tools and datasets. Results can be used to (1) identify where a suitable fish-specific TRV already exists, and (2) to highlight where effects information may be limited for a given contaminant, thus necessitating development of site-specific TRVs and/or use of other lines of evidence to assess risks to fish from exposure to contaminants.

Speaker: Meara Crawford, MRM, RPBio

Meara Crawford is an environmental scientist who has been working with Azimuth Consulting Group Inc., based out of their Sidney office, for almost 6 years. She has been involved in ecological and human health risk assessments for metals and hydrocarbons at sites across BC, including mining-related operations, historical construction camps, and other industrial sites. She also has past work experience in applied environmental biology with both provincial and federal governments, and an educational background in applied environmental toxicology, ecology, and chemical risk assessment. An ideal work day for her work includes time spent digging deep in technical and scientific details, mixed with constructive brainstorming conversations with colleagues to help work through interesting projects.