From the Introduction: "Over the past couple of decades, national attention to 'emerging contaminants' or 'contaminants of emerging concern' (CECs) in surface water and groundwater has been increasing. Although there is no federal statutory or regulatory definition of CECs, generally, the term refers to unregulated substances detected in the environment that may present a risk to human health, aquatic life, or the environment. CECs can include many different types of manmade chemicals and substances--such as those in personal care products, pharmaceuticals, industrial chemicals, lawn care and agricultural products, and microplastics--as well as naturally occurring substances such as algal toxins or manganese. [...] Some stakeholders have asserted that EPA [U.S. Environmental Protection Agency] could be more effective in using its existing CWA [Clean Water Act] authorities to address CECs, while others have suggested a need to identify and address potential gaps in CWA authorities through amendments to the statute. This report examines authorities available to address CECs under the CWA."
CRS Report for Congress, R45998
Congressional Research Service: https://crsreports.congress.gov/