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Studies Find that Thousands of Cancer Cases May Be Linked to California Tap Water

A new study claims to have revealed a link between cancer and drinking water in California. According to the study, drinking water from California taps may increase cancer cases by more than 15,000 throughout the state over the course of a lifetime. The study focused on the combined effects of multiple pollutants in drinking water rather than analyzing just one contaminant.

The data in the study conducted by scientists from the Environmental Working Group included 2700 California community water systems from 2011 to 2015. The study found that over the course of 70 years, 221 annual cancer cases would have been caused by drinking water pollution. Individuals in small to midsize communities were subject to the greatest risk of cancer from carcinogens in drinking water. According to the study, in 495 water systems affecting over 3 million people, the cancer risk was greater than 1 additional case per 1000 people. In 1,177 systems affecting more than 28 million people, the risk of contracting cancer was 1 per 1,000 to 1 per 10,000 people.

One of the chemicals evaluated was arsenic, which, according to the study, accounted for an additional 7,251 cases of cancer. Many experts believe that there is no safe level of arsenic in drinking water, but arsenic remains a significant issue in groundwater in certain areas. Arsenic contamination in drinking water can result either from natural causes or industrial and agricultural activities. Some of the other pollutants that the study looked at include disinfectant byproducts and hexavalent chromium, also known as chromium-6.

In the past, regulators have tested and implemented restrictions based on health hazards from individual chemical substances. In contrast, this study looked at the cumulative impact of a variety of pollutants in tap water. The study purports to be the first of its kind to analyze pollutants in this manner.

The study concluded that lowering the legal limits for many of these pollutants was necessary since pollutants at concentrations below allowable levels accounted for 85% of the estimated cancer risk. In fact, 90 percent of the 2,737 community water systems in California conformed to applicable federal standards for the past seven years.

Grimaldi Law Offices has been advising clients for over 20 years on chemical and product law. For knowledgeable advice and in-depth analysis on your chemical regulatory compliance obligations, contact Grimaldi Law Offices at (415) 463-5186 or email us at [email protected].






Ms. Grimaldi maintains a diverse environmental law practice focusing on chemical and product regulation and litigation defense. Her practice areas include Proposition 65, California's Safer Consumer Products Regulations, California's Rigid Plastic Packaging Container Act and the federal Toxic Substances Control Act. Ms. Grimaldi graduated from the University of California Hastings College of the Law magna cum laude and holds a Bachelor of Science Degree in Bacteriology from University of California, Davis. Prior to attending law school, she worked as a research assistant in laboratories at the University of California, San Francisco Cancer Research Institute and at the University of California, San Francisco School of Medicine.