EWG Map Supports ‘Co-Contaminant’ Tap Water Rules for Preventing up to 50,000 Cancer Cases

Regulating and treating multiple drinking water contaminants as groups, instead of the standard method of targeting one at a time, would significantly benefit public health.

Millions of Americans have drinking water contaminated with hexavalent chromium and arsenic or nitrate, or all three, a new EWG map shows.

Treating tap water for these and other pollutants at once could prevent up to 50,000 lifetime cancer cases in the U.S, a recent peer-reviewed EWG study finds. For example, ion exchange is a water treatment that can help reduce arsenic, nitrate and hexavalent chromium together at once. This in turn lowers the cancer exposure risk for people drinking that water across the board.

The development of federal drinking water rules currently relies on the same years-old approach of focusing on a single contaminant. But grouping contaminants would support water utilities’ investment in treatment technologies that can be enhanced to reduce multiple pollutants simultaneously.

The sheer scale of drinking water contamination with hexavalent chromium and either arsenic or nitrate or both suggests the need to focus on approaches for regulating and treating several substances at once.