EWG Drinking Water Quality Commentary Water Issues Committee May 15, 2019

Who is the Environmental Working Group (EWG)? Non-profit 501(c)(3), based in Washington, DC Maintain affiliated 501(c)(4) lobbying organization Publish articles, guides, and “studies” on many topics: Pesticide residues (i.e., the “Dirty Dozen”) Cosmetics and sunscreens Energy and Farm Policy Tap water quality

EWG “Commentary” on Tap Water in CA Published in journal Environmental Health on April 30th, 2019 Not subject to traditional scientific peer-review process Analyzed publicly available data in CA state database 2,737 public water systems (i.e., “Producers”) 2011 to 2015 time period Applied a new “cumulative risk” methodology to data

Local/National/International Media picked up story

EWG “Commentary” Findings Up to 15,449 lifetime cancer cases could be related to drinking water Represents 0.04% of 38.7 million CA resident population American Cancer Society  38% lifetime cancer development risk & 20% cancer death risk in USA Percent of estimated cancer risk due to specific contaminants Arsenic = 47% (has enforceable MCL) Disinfection Byproducts = 34% (has enforceable MCL) Hexavalent chromium = 16% (MCL to be reissued) All others (radiologicals, VOCs) = 3% (have enforceable MCLs)

Conclusions Highest estimate risks found in small water systems Defined as serving <10,000 people 31% of estimated cancers found in 495 small systems serving <10% of state population Limited water supply options, funding, trained personnel, capacity for treatment Only 10 public small systems in OCWD service area OCWD does sampling, testing, reporting on their behalf OCWD + Producers demonstrate that their water supplies meet all state and federal standards