Household Chemicals End Up in Cape Cod Drinking Water

Dec 21, 2015

Antibiotics, pain medications, birth control pills, facial cleansers, shampoo, laundry detergent, dish detergent, the non-stick coating on those skillets, and even the waterproofing on that winter coat. In addition to being found in your home, they can now be found in groundwater, ponds, and coastal bays around Cape Cod.

Many of the medicines we take and the household products we use end up going down our drains and straight through our septic systems into the environment. Some actually come full circle and make it back into our drinking water.

The quantities are minute - just parts per trillion, equivalent to drops of water in twenty Olympic-sized swimming pools. Medicines are designed to be biological active at low levels, though, and many other household chemicals have been shown to be hormone-like or cancer-causing at higher concentrations. What's more, studies have shown that fish living near wastewater treatment plants sometimes have elevated rates of cancer or endocrine disruption, such as male fish with female attributes. So, naturally, there's concern about human health risks.

Before we can start thinking seriously about treating or regulating these chemicals, though, we have to be able to find and follow them. And that's difficult. For one, there are hundreds of chemicals, collectively known as contaminants of emerging concern, and testing for them can be expensive. Monitoring for most emerging contaminants isn't required by law, since it would be cumbersome and health effects aren't proven.

But another common component of wastewater - nitrogen - could provide a shortcut for identifying water sources at risk for high levels of emerging contaminants. Human waste contains a lot of nitrogen, and wastewater managers already measure it. Recent research by Silent Spring Institute has shown that water sources with high nitrogen levels also tend to have detectable levels of pharmaceuticals. Of course, nitrogen levels can't predict which other contaminants might be present, or track chemicals that come down sink drains instead of through the toilet.

At the very least, though, it's a piece of information consumers can get their hands on to gauge how concerned to be about their water, and whether additional steps, like water filtration at the household level, are warranted.


  • Laurel Schaider, research scientist at Silent Spring Institute
  • Tom Cambareri, watershed management┬ádirector for the Cape Cod Commission
  • Amy Costa, director of the Cape Cod Bay Monitoring Program at Center for Coastal Studies