Management controls put in place by the EPA to
regulate and control hazardous chemical
discharges from sewage treatment plants to
water resources have limited effectiveness. The
EPA regulates hazardous chemical discharges to
and from sewage treatment plants, but these
regulations are not effective in controlling the discharge of hundreds of hazardous chemicals to surface waters such as lakes and streams. Sewage treatment plant staff do not monitor for hazardous chemicals discharged by industrial users. This is due to a general regulatory focus on the priority pollutants list that has not been updated since 1981, limited monitoring requirements, limited coordination between EPA offices, a lack of tracking hazardous waste notifications required for submittal by industrial users, or a lack of knowledge of discharges reported by industrial users under the Toxics Release Inventory. Except for EPA Region 9, sewage treatment plant permits generally include very few monitoring requirements or effluent limits, which can limit enforcement actions.

Read the 31 page report:

epa-report-sep2014-hazardous-chemicals-released-into-water