EVALUATION OF THE FACTORS RELATING COMBINED SEWER OVERFLOWS WITH SEDIMENT CONTAMINATION OF THE LOWER PASSAIC-RIVER

The relationship between combined sewer overflows (CSOs) and sediment contamination of the lower Passaic River in New Jersey was evaluated t o identify the nature of toxic chemical inputs to the river, estimate the magnitude of CSO inputs to other sources and assess the potential overall impact on sediment quality. Of the estimated 5000 facilities t hat discharge industrial effluent to the combined sewerage system alon g the Passaic River, approximately 400 facilities hold National Pollut ant Discharge Elimination System (NPDES) permits, Seventy-eight permit ted facilities, representing 14 major industrial classes with discharg es exceeding 190 000 l day(-1), were identified within 33 CSO district s that are below the Second River and serviced by the Passaic Valley S ewerage Commission. A wide range of toxic chemicals, including heavy m etals, pesticides, polychlorinated dibenzo-p-dioxins and dibenzofurans , polychlorinated biphenyls and polycyclic aromatic hydrocarbons were found to be associated with numerous industries located within the CSO districts. Many of these chemicals have been measured in CSO discharg es to the river during wet weather flow events and have also been meas ured in river sediments. The magnitude of the CSO discharges (billions of litres per year) to the lower Passaic River, combined with the nat ure of the chemicals used and discharged to the system by industrial s ources, indicates that CSOs represent an historic and ongoing source o f toxic pollutants to the river. While the US Environmental Protection Agency (EPA) has recently developed an aggressive programme for reduc ing the impact of CSOs on the nation's waters, it will likely be many years before the benefits of this programme are realized, particularly in areas with antiquated sewer systems such as those within the Passa ic River basin. (C) 1996 Elsevier Science Ltd