| Simple models of drainage basin holdup and post-depositional mixing are introduced and applied to the interpretation of 137Cs and other tracer profiles in dated cores collected from lakes and reservoirs in New York State. Three cores collected from two New York City drinking water reservoirs are well described by a 3–4 year halftime of delayed delivery followed by simple, complete mixing of sediments to a fixed depth. Model results are consistent with the 3–5 year holdup of atmospheric 137Cs indicated by historical measurements in tapwater. Application of the models to a core from Central Park Lake is a necessary step in constraining flux estimates for atmospherically deposited contaminants in the New York City urban environment.; This study presents a first attempt at characterizing atmospheric, wastewater, industrial, and upstream Hudson River sources of PCDD/F to sediments of New York Harbor. The ratio of 2,3,7,8-TeCDD/ΣTeCDD is particularly indicative of runoff' from a former 2,4,5-T manufacturing site on the Passaic River. This ratio is quite low (ca. 0.06) in other source-indicator sediments and an order of magnitude higher in sediments influenced by 2,4,5-T production. 2,3,7,8-TeCDD contamination in recent and historical sediments of the New York/New Jersey Harbor appears to be dominated by the Passaic River source.; Current and historical deposition of PCBs in the New York City area is characterized by greater abundance of higher chlorinated (hexa- and greater) congeners than in harbor and upstream sediments. Modeling of the Central Park lake core provides an atmospheric flux estimate of ca. 10 ng PCB/cm 2/yr, in reasonable agreement with flux estimates calculated from air concentration data. Flux to the Muscoot Reservoir is similar at ca. 15 ng/cm2/yr and may reflect the influence of local sources. PCB flux to the rural Ashokan Reservoir is calculated as 1.4 ng/cm2/yr. Atmospheric flux may account for as much as ca. 8–15% of the total PCBs and 28–44% of the higher chlorinated congeners in mid-1990s deposition in New York Harbor. |
