Emerging contaminants are important because the risk they pose to human health and the environment is not yet fully understood.

Pharmaceuticals, personal care products (PCPs) and endocrine disrupting compounds (EDCs) are among the prime examples of emerging contaminants. Up to 90% of oral drugs pass through the human body and end up in the water supply. Personal care products (soaps, cosmetics, fragrances, etc.) also find their way into our water. Endocrine disruptors are substances that may interfere with the function of hormones in the body. Trace amounts of these contaminants are being discovered in water throughout the country.  The U.S. EPA is working to improve its understanding of several emerging contaminants, including perchlorate, pharmaceuticals, PCPs and EDCs.

Emerging pollutants can be understood in a broad sense as any synthetic or naturally-occurring chemical or any microorganism that is not commonly monitored or regulated in the environment with potentially known or suspected adverse ecological and human health effects. These contaminants include mainly chemicals found in pharmaceuticals, personal care products, pesticides, industrial and household products, metals, surfactants, industrial additives and solvents. Many of them are used and released continuously into the environment even in very low quantities and some may cause chronic toxicity, endocrine disruption in humans and aquatic wildlife and the development of bacterial pathogen resistance.

Scientific knowledge and understanding on potential human and ecosystem health risks posed by emerging pollutants is still very scarce, as well as on their presence in water resources and wastewater and their pathways and accumulation in the environment. Most emerging pollutants are not regulated in environmental, water quality and wastewater discharge regulations. Hence, there is an urgent need to strengthen scientific knowledge and adopt appropriate technological and policy approaches to monitor emerging pollutants in water resources and wastewater, assess their potential human health and environmental risks, and prevent and control their disposal to water resources and the environment.