No Herbicides or Pesticides into Water

This article is about the Chesapeake Bay Watershed but applies equally to all watersheds: Pesticides used by farmers, residents and business owners pose a significant risk to Chesapeake Bay wildlife and human health, according to a recent report released by the Maryland Pesticide Network.

Pesticides and the Maryland Chesapeake Bay Watershed lists the major types and sources of pesticides in the Bay region and explains how pesticides can affect the fish we eat and the water we drink. Toxic chemicals in pesticides can move up the food web when larger fish and birds eat smaller, contaminated organisms. Humans can also be affected if they catch contaminated fish or drink contaminated water.

According to the report, pesticides are a threat to the region’s environmental health because they can be toxic to aquatic life, wildlife and humans, even though those species are not being targeted by the pesticide applier. Even at low levels, toxic effects of pesticides can put additional stress on fish, plants, microscopic animals and other species. A 2007 report by the U.S. Geological Survey found that synthetic organic pesticides were widely detected at low levels throughout the Bay watershed.

One type of pesticide discussed in Pesticides and the Maryland Chesapeake Bay Watershed is atrazine, the most commonly used herbicide in the United States. Atrazine, which is used in both agriculture and on lawns, has been linked to sexual abnormalities in frogs and is a suspected endocrine disruptor: a substance that mimics hormones and can cause reproductive anomalies.

Pesticides get into our local waterways and the Chesapeake Bay when we apply them to the ground and rain washes them into nearby streams and storm drains. The largest source of pesticides in the Bay watershed is from agriculture, but commercial, residential and government properties also contribute measurable amounts of pesticides to local waterways and groundwater supplies. Pesticides used in our homes, such as the antimicrobial ingredient triclosan in soaps and personal care products, can also find their way into the Bay through treated wastewater.

Chemical pesticides and herbicides help protect crops from insects, weeds and fungus. Just like fertilizers, when pesticides are applied in excess, they can make their way into local rivers and streams and potentially impact aquatic life. Pesticides can also soak into groundwater supplies, a source of drinking water in many Bay watershed communities.