Developing Baseline Risk Fish Ingestion Estimates

Evaluating alternative remedial options under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLE) requires understanding human health risk under regulatory baseline conditions as specified in the national Contingency Plan [55 FR 8711] (NCP). As the preamble to the NCP describes, “…one specific objective of the risk assessment is to provide an analysis of baseline risk (i.e, the risks that exist if no remedial action or controls are applied to a site).” Fish consumption advisories are considered a form of institutional control (U.S. Environmental Protection Agency [USEPA] 2010). Therefore, the baseline risk assessment requires estimates of fish consumption if the site-specific fish consumption advisory were not in force, but all other site conditions were the same (not in force means that a posted sign is not present on site and/or published materials warning anglers about risks from consiming site fish and crab are not available).

This manuscript presents a methodology for developing baseline-risk fish-ingestion estimates using site-specific data. The methodology involves linking current trip-taking and consumption to baseline trip-taking and consumption via behavioral modeling supported by survey research. The manuscript provides an empirical example of the methodology by developing baseline-risk fish-ingestion estimates for the Lower Passaic River Study Area (LPRSA) — a 17-mile stretch of urban and industrial river in northeastern New Jersey.

The results of the analysis estimate a mean of 0.85 grams per day for the 90th percentile of all LPRSA anglers (consumers and non-consumers) under baseline risk conditions. By comparison, default rates prepared for the LPRSA have been as high as 34.6 g/day (USEPA 2014). This default rate is also higher than estimates for the population of LPRSA consuming anglers who consume at the 90th (3.14 g/day), 95th (5.19 g/day), and 99th percentile (15.13 g/day).