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Figure 6-16 Time history of copper and lead in a sediment core in the low-salinity reach of the Hudson estuary. Sediment core collected in 1986, 55 miles (88.6 km) from the mouth of the estuary. Source: Valette-Silver, 1993.

ducted at Columbia University have documented a 50 to 90 percent reduction from the 1960s and 1970s in most trace metals and chlorinated organic compounds in finegrained sediments of the Hudson River (Chillrud, 1996). Sediment toxicity, however, has been identified for the Upper East River, Arthur Kill, Newark Bay, and Sandy Hook Bay. The observed distribution of sediment toxicity appears to be most strongly related to polynuclear aromatic hydrocarbons (PAHs) rather than trace metals (Wolfe et al., 1996). Historical point and nonpoint source loading estimates for the Hudson-Raritan estuary are presented elsewhere for other trace metals, PCBs, total suspended solids (HydroQual, 1991), total organic carbon (Swaney et al., 1996; Howarth et al., 1996) and nutrients (HydroQual, 1991, 1999; Carpenter, 1987). Using a steady-state toxics model, the New York-New Jersey Harbor Estuary Program has also developed mass balance analyses for copper, nickel, and lead and a preliminary mass balance for mercury and PCBs (HydroQual, 1995b).

Municipal wastewater discharges account for only one point source component of the total loading of pollutants to the Hudson-Raritan estuary from point and nonpoint sources. In order to properly place the magnitude of municipal wastewater loads in the context of the total point and nonpoint source pollutant loads discharged to the estuary, estimates of the contributions from tributaries, municipal and industrial point sources, CSOs and urban stormwater of the Middle and Lower Hudson basins have been compiled as a budget based on data compiled for conditions during the 1990s. Table 6-2 illustrates that the relative significance of different sources is dependent on

TABLE 6-2 Pollutant Loadings to the Hudson-Raritan Estuary (in Percent)

Parameter

Tributary (%)

Municipal Effluents (%)

Combined Sewer Overflow (%)

Stormwater (%)

Other" (%)

Total Load (Units)

Flow

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