Society’s ability to solve problems through innovation is incredible and great benefits are enjoyed by many. Unfortunately sometimes that innovation involves new pollutants or contaminants that can make their way into our streams and lakes.

New advances in pharmaceuticals, agriculture and industry are accompanied by different chemicals that can be harmful to aquatic life. Things such as endocrine disrupters, new pesticides or even non-stick coatings can have unknown and unstudied effects on fish and invertebrates that live in streams and lakes. These new or unstudied contaminants are sometimes collectively referred to as “Pollutants of Emerging Concern.” Below are a few categories and examples of these emerging contaminants.


There is a growing concern about pharmaceuticals appearing in our water bodies and drinking water. Many pharmaceutical drugs bass through the body and are excreted out in human urine. Expired and unused prescriptions and medications are sometimes improperly disposed of down a drain or toilet when no longer needed. Not all pharmaceuticals have known effects on aquatic life. Some are known as endocrine disrupters or chemicals that manipulate the endocrine or hormonal system of humans and animals. Information about where and how to dispose of unwanted medication is available in the department's Proper Disposal of Household Pharmaceutical Waste - PUB2291 publication.


Pesticides are used to kill, repel or control certain forms of plant or animal life that are considered to be pests. They provide a way to control insects on food crops, rodents that carry diseases and mold and mildew growth. As pests become tolerant of commonly used pesticides, new pesticides are developed to combat them. If improperly disposed of or misused through improper application, such as over-spraying, pesticides can make their way into our soil and groundwater or runoff into streams and lakes. Invertebrates in streams are also insects, just the aquatic or larval forms of the land dwelling (terrestrial) varieties. Pesticides designed for terrestrial insects also affect aquatic insects through the same pathways. For information about how to dispose of your unwanted pesticides, visit Household Hazardous Waste. The department's Missouri Pesticide Collection Program offers Missouri farmers and households an opportunity for safe, free disposal of unwanted or unusable pesticides. 

Per- and Polyfluoroalkyl Substances (PFAS)

PFAS are a group of manmade fluorinated chemicals that have been used in industry and consumer products since the 1940s because of their ability to repel both water and oil. These chemicals can be found in products such as non-stick cookware, carpet, clothing, furniture fabrics, waxes, cleaning products, some firefighting foams and in industrial applications. Many PFAS break down very slowly and can build up in people, animals and the environment over time. Scientific studies have shown that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals. There are thousands of different PFAS, the three most studied being perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and polytetrafluoroethylene (Teflon). For more information about PFAS in Missouri, visit Per- and Polyfluoroalkyl Substances (PFAS).