Managing emerging contaminants in watersheds: Need for comprehensive, systems-based strategies

While much has been done to reduce conventional pollutants in watershed systems, emerging contaminants (ECs) are posing a major threat to health and environment. These contaminants pose a threat to humans and to ecosystems. There is a critical need for comprehensive strategies that aim at watershed system-wide abatement (source-transfer-fate levels) using both structural and nonstructural approaches. In this study, we review sources, occurrence and harmful impacts of ECs with an eye toward watershed-scale mitigation strategies at source, transfer, fate, and organismal response levels. The use and efficiency of activated carbon, ozonation, photocatalysis, photo fenton, reverse osmosis and constructed wetlands are useful in mitigation. Management priority is needed for pharmaceuticals, personal care products, pesticides, and industrial contaminants that are increasing in frequency and concentrations. Structural approaches at source level can include best management practices like buffer strips, riparian management, natural and constructed wetlands. These natural strategies are cost-effective for small communities due to low operational cost and energy consumption. Non-structural approaches can include dissemination of information, education, outreach, incentives for mitigation, and policy mechanism for compliance. A comprehensive, watershed-based, systems approach with multi-level strategies at source, transfer and sink level for efficient abatement of ECs and sustainability of watershed systems.