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1 [1] (August 18, 2015)

handle is hein.crs/govccwy0001 and id is 1 raw text is: FF.ri E.$~ & Updated August 18, 2015 Algal Toxins in Drinking Water: EPA Health Advisories On June 17, 2015, the Environmental Protection Agency (EPA) issued drinking water health advisories for two algal toxins to help water providers address threats to drinking water supplies from harmful algal blooms (HABs). Blue-green algae (cyanobacteria) occur naturally in marine and fresh water and can produce numerous potent algal toxins (cyanotoxins). Exposure to cyanotoxins can cause a range of adverse health effects, from rashes to severe illness and, rarely, death. A confluence of conditions-including warm water temperatures, excess nutrients (mainly nitrogen and phosphorus) and strong sunlight-can trigger explosive growth of cyanobacteria, creating harmful algal blooms. These HABs can contaminate drinking water supplied from surface water or groundwater directly influenced by surface water. Further, HABs appear to be increasing. EPA's 2009 National Lakes Assessment found microcystins, one of the more common and potentially harmful cyanotoxins, to be present in one-third of lakes surveyed nationwide. In August 2014, microcystins produced by a bloom in Lake Erie contaminated a water system serving Toledo, Ohio, and surrounding areas for several days. No federal drinking water standards were available for managing this or other cyanotoxins, nor were rapid and sufficiently specific analytical methods available to meet the needs of water providers faced with quickly identifying, measuring, and removing the toxins to ensure the safety of water supplies. As a trigger for taking action, water managers used the state guideline of 1 microgram per liter (pg/L) for microcystin- LR (one of the more common and harmful variants of microcystin). The immediate problem was resolved; however, this and other incidents added urgency to EPA's efforts to assess cyanotoxin risks to public water supplies. EPA has been conducting research on several common cyanotoxins-microcystins, cylindrospermopsin, and anatoxin-a-and evaluating them for possible regulation under the Safe Drinking Water Act (SDWA). The agency has also worked to validate analytical methods to enable the measurement of these cyanotoxins in water at lower concentrations and with greater accuracy and precision. However, technical challenges and information gaps on the toxins' health effects and occurrence have thus far prevented EPA from determining whether the cyanotoxins meet the criteria for regulation under the SDWA. In light of the impacts of the Lake Erie HAB and the increasing frequency of HABs nationwide, EPA set a goal to issue health advisories for the three types of cyanotoxins ahead of the 2015 summertime algal bloom season. The SDWA authorizes EPA to issue health advisories for contaminants that are not regulated under the act (42 U.S.C. §300g- 1 (b)(1)(F)). Health advisories include non- enforceable guideline values for contaminants in drinking water (based on non-cancer health effects) and often include values for different exposure durations: one day, 10 days, several years, and lifetime. Advisories also provide technical guidance on identifying, measuring, and treating contaminants in drinking water. On June 17, 2015, EPA issued several resource documents related to HABs, including drinking water health advisories for microcystins and cylindrospermopsin (80 Federal Register 34637). Because of insufficient health effects data, EPA was unable to issue an advisory for anatoxin-a. The advisories include levels for the cyanotoxins in drinking water at or below which adverse health effects are not expected to occur based on short-term (10-day) exposures (Table 1). They also include information on analytical methods that water providers can use to test for the presence and concentrations of the toxins and treatment techniques to remove them from drinking water. EPA also issued Recommendations for Public Water Systems to Manage Cyanotoxins in Drinking Water, a technical document to help water providers develop cyanotoxin management strategies (e.g., determining when and how to monitor and treat water and when and how to notify the public and officials at different toxin levels). Table I. Cyanotoxin Health Advisory Levels 10-day exposures, micrograms per liter (pg/L) Microcystins Cylindrospermopsin Children less 0.3 0.7 than 6 years old Ages 6 and older 1.6 3.0 Source: EPA, 2015 Drinking Water Health Advisories for Two Cyanobacterial Toxins, Fact Sheet, http://water.epa.gov/drinl/ standards/hascience.cfm#micro. Notes: EPA recommends utilities issue do not drink, do not boil notices when toxins exceed values for ages 6 and older. Targeted notification for sensitive groups is suggested when toxin levels exceed the lower value but not the higher value. EPA worked with Health Canada to develop health advisories. The World Health Organization (WHO) issued a provisional drinking water guideline for microcystin- LR of I pg/L in 1998. Ohio and Oregon use this same guideline level. Minnesota set a guidance level of 0.04 pg/L. Seventeen countries have adopted microcystin-LR guidelines ranging from 1.0 pg/L to 1.5 pg/L. While broadly supporting EPA efforts, the American Water Works Association has noted technical, policy, and cost issues with the recommendations document and has asked .O 'T gognpo 'popmm- , goo g , q 'S a X 11LULANJILiN,

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