A review of algal toxin exposures on reserved federal lands and among trust species in the United States

Abstract

Associated health effects from algal toxin exposure are a growing concern for human and animal health. Algal toxin poisonings may occur from contact with or consumption of water supplies or from ingestion of contaminated animals. The U.S. Federal Government owns or holds in trust about 259 million hectares of land, in addition to the Trust species obligations. We completed the first comprehensive review of potential toxin-producing algal blooms in surface waters on Federal lands and Trust species exposed to algal toxins. Events were sorted into three tiers based on potentially toxic algae abundance or toxin concentration and related effects on animal morbidity and mortality. At least 11.1% of Federal lands are known to have been affected by algal events, but exposure is likely underreported. The occurrence of potential toxin producers and their toxins (Tier 1) have been documented 337 times, health advisory threshold exceedances (Tier 2) were reported 943 times, and 86 events involved animal sickness or death linked to cyanobacteria or marine toxins (Tier 3). Trust species exposed to cyano- or algal toxins included marine mammals, migratory birds, threatened and endangered species, and species of concern. We report numerous data gaps ranging from potential effects on human health from consuming intoxicated animals to the infrequency of measuring and reporting certain toxins. Improvements to field and laboratory methods, more consistent evaluation of toxin exposure, decreased latency on data analysis, delivery and interpretation will be necessary to improve response and management strategies for protecting human and animal health where issues persist.

Keywords:

• Federal land management
• cyanotoxins
• algal toxins
• wildlife
• Trust species
• harmful algal blooms

HANDLING EDITORS:

• Eakalak Khan and Lena Ma

Acknowledgments

The authors wish to express appreciation for numerous improvements suggested by anonymous and USGS peer reviewers (Barnett Rattner, Viviana Mazzei, and Jodi Burgess). We are additionally grateful for useful comments on marine algal toxins regulations and advisories for beaches and fish and shellfish issues provided by Quay Dortch (NOAA) and comments on red tide by Richard Clark and Monica Samit (Florida Department of Health). Funding for this review was provided by the U.S. Geological Survey’s Environmental Health Toxic Substances Hydrology Program. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.