Domoic Acid (DA) is a marine-based toxin produced by the diatom Pseudo-nitzschia. Based upon nearly 100 Canadian cases of acute toxicity in 1987, a regulatory limit for DA (20 ppm) was established for shellfish consumption. This has been protective against acute cases of Amnesic Shellfish Poisoning, seizures, coma, or death in the U.S. However, recent longitudinal cohort studies of coastal WA Native Americans (NA) provide new evidence that current criteria are not protective against chronic toxicity. A decrease in memory function in adult high consumers over time and psychomotor slowing in perinatally exposed children occurs at much lower doses. Thus, consumption advisories are in place for vulnerable members of the Makah, Quileute, and Quinault Nations in Washington State. In response to this, an important immediate question remains for scientists, epidemiologists and Washington Department of Health officials: What are the implications of these findings for non-NA razor clam consumers? The objective of this study is to work with the Washington Departments of Health (WDOH) and Fish and Wildlife to provide an immediate response to new data and concerns related to the potential human health threat of chronic exposure to low levels of domoic acid (DA) via razor clam consumption. Toward this end, the development of a risk assessment framework for non-NA razor clam consumers is proposed.
Specific aims i nclude 1) developing provisional chronic oral reference doses (RfDo) for DA, building upon the toxicity data from the NA tribes; 2) characterizing the exposure (and associated risk factors) of 1100 non-NA razor clam harvesters through harvesting beach surveys and 3) identifying areas/conditions that represent the highest risk for development of chronic toxicity (based on DA levels and consumption patterns) using geospatial analyses. These risk assessment studies will be completed over the next 12-24 months. An active research partnership with the Washington Department of Health will speed the adoption, use and translation of the findings into a form useful to support regulatory decision making.

Public Health Relevance

The proposed project will provide the information necessary to protect people at risk of illness due to long, term repeated exposure to low levels of domoic acid (DA) through razor clam consumption in the state of Washington. By working in collaboration with the Washington Department of Health, the findings of this study may be used to support regulatory decision making.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Exploratory/Developmental Grants (R21)
Project #
3R21ES028060-02S1
Application #
9699242
Study Section
Program Officer
Tyson, Frederick L
Project Start
2017-04-01
Project End
2019-03-31
Budget Start
2018-09-10
Budget End
2019-03-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Maryland Baltimore
Department
Neurology
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201