2014-15 Fish Consumption Survey

Fish consumption is one factor used to set water quality standards for the protection of human health. In April 2014, DEQ initiated a year-long statewide survey to estimate fish consumption rates among Idaho residents. This research is meant to provide reliable measures of how much fish and seafood Idahoans consume and how much of that fish comes directly from Idaho's lakes and streams.

The survey was designed to be as broad and inclusive as possible. More than 4,500 Idahoans, including a subset of resident anglers, were randomly selected and asked to complete a telephone survey. Everyone in Idaho had a possibility of being selected. This ensured that the study was all inclusive and that the results could be reliably projected to the general population. Participation was voluntary.

Once the survey was completed, DEQ turned the data over to Information Management Services (IMS) for processing. Using the National Cancer Institute, IMS turned dietary recall data into a distribution of fish consumption rates. This data was then used in a probabilistic risk assessment, performed by Windward Environmental, to derive potential criteria, although ultimately it was decided to adopt water quality criteria using traditional deterministic calculations.

EPA also sponsored fish consumption surveys of Idaho’s tribal populations. The fish consumption surveys concluded in April 2015, resulting in DEQ using a fish consumption rate of 66.5 grams per day for calculating water quality toxics criteria.

The research was needed because the United States Environmental Protection Agency (EPA) disapproved Idaho’s current water quality criteria set to protect human health because they could not determine that the fish consumption rate the criteria were based on represented all Idahoans and were thus protective. DEQ underwent a negotiated rulemaking from 2012 through 2015 to revise the disapproved water quality criteria set to protect human health. The design of the Idaho survey as well as interpretation and use of the data were discussed with those who participated in the negotiations.

Peer Review

Three reports were peer-reviewed: 1) the survey of fish consumption, 2) the data processing into a distribution of fish consumption rates; and 3) application of the data in probabilistic risk assessment. To provide independence in the review, Versar Inc. was contracted to arrange for and provide review by three individuals: Patricia Guenther, PhD in nutritional sciences and an independent consultant; Alanna Moshfegh, MS, RD and a research leader with the Food Surveys Research Group of USDA; and Janet Tooze, PhD, MPH, associate professor in the Department of Biostatistical Sciences, Wake Forest School of Medicine. DEQ also received peer review comments from Westat, arranged by EPA Region 10.

Response to Peer Review

Once DEQ had all peer review comments in hand, contractors were asked for three pieces of work to provide a response. In each case, this resulted in revised reports to clarify certain matters. There was no change in the underlying data collected.

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