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Cyanotoxins and the Safe Drinking Water Act: Drinking Water Protection Act, Contaminant Candidate List and the Unregulated Contaminant Monitoring Rule

Drinking Water Protection Act

EPA developed, and submitted to Congress, a strategic plan outlining how the agency will continue to assess and manage algal toxins in drinking water provided by public water systems. The strategic plan outlines approaches and projects to better understand human health impacts from cyanotoxins, control and manage algal toxins in source water, and treat algal toxins in drinking water, with the goal of ultimately protecting water quality and public health. EPA developed this strategic plan in response to the 2015 Drinking Water Protection Act (also known as H.R. 212).

Contaminant Candidate List (CCL)

The Safe Drinking Water Act (SDWA), as amended in 1996, requires the EPA to publish a list of contaminants every five years that are known or anticipated to occur in public water systems and which may require regulation under the SDWA. This list is called the Contaminant Candidate List (CCL). The EPA's Office of Water listed cyanobacteria (formerly known as blue-green algae), other freshwater algae and their associated toxins on CCL 1 (1998) and CCL 2 (2005). Cyanotoxins were included on CCL 3 (2009) and the CCL 4 (2016). Based on toxicological, epidemiological and occurrence studies, the cyanotoxins anatoxin-a, cylindrospermpsin, microcystins and saxitoxin were listed as examples of cyanotoxins of concern.

Fourth Unregulated Contaminant Monitoring Rule (UCMR 4)

The 1996 Safe Drinking Water Act (SDWA) amendments require that once every five years EPA issue a new list of no more than 30 unregulated contaminants to be monitoried by public water systems. The fourth Unregulated Contaminant Rule (UCMR 4) was published in the Federal Register on December 20, 2016. UCMR 4 requires monitoring for 30 chemical contaminants, including cyanotoxins, between 2018 and 2020 using analytical methods developed by EPA and consensus organizations.