Dangerous nitrate pollution has contaminated the groundwater that supplies private drinking water wells and public water utilities in several agricultural regions across the United States, posing a significant threat to people's health. A new report from the Center for Progressive Reform (CPR) indicates that this problem has reached Maryland's Lower Eastern Shore, an area that's home to hundreds of concentrated animal feeding operations (CAFOs) and millions of chickens.

Nitrates are a compound formed when nitrogen, largely from manure and fertilizer, breaks down. When manure is overapplied or mismanaged, rainfall or irrigation can cause nitrates to trickle down through soil into groundwater resources. Tainted Tap: Nitrate Pollution, Factory Farms, and Drinking Water in Maryland and Beyond notes that a single poultry CAFO raising 82,000 laying hens can produce 2,800 tons of manure a year, more than three times the amount produced by the Maryland Zoo in Baltimore each year.

Though private well testing data is limited, our investigation found indicators that pollution associated with CAFOs is contaminating the groundwater that residents rely on for their drinking water. Since nitrates are colorless, tasteless, and odorless, most families don't even know that it's in their water. We examined currently available data …