Deposition

Ash-laden runoff samples collected near Ground Zero soon after the September 11, 2001 attack on the World Trade Center (WTC) and subsequent fire demonstrate the release of polychlorinated biphenyls (PCBs), polybrominated dipheyl ethers (PBDEs), polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans (PBDD/Fs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), and tetra- and pentachlorinated biphenylenes (PCBPs) from the incident. Relative abundances of PCDD/F congeners in the runoff water and post-disaster lower Manhattan dust samples were different from those seen in pre-disaster NYC combined sewer outfall (CSO) samples. The WTC-related samples showed a greater relative abundance of 2,3,4,7,8-PeCDF than usually seen in CSOs, sludges, and treated wastewaters. This congener may be associated with certain types of incineration. Comparison of sediment and water samples collected in the lower Hudson River before and shortly after September 11, 2001 (9/11) showed no changes in PCB or PCDD/F concentrations or homologue profiles determined down to the parts per quadrillion range. Comparisons of ambient water samples collected post-9/11 with archived samples suggest that the WTC disaster did not significantly impact ambient concentrations of the target chemicals. Ambient concentrations of PBDD/Fs in New York Harbor are similar to those of PCDD/Fs, suggesting that these contaminants deserve increased scrutiny with respect to toxicity, sources, and fate in the environment.

Acoustic Doppler current profilers (ADCPs) can provide data needed for computation of suspended-sediment discharge in complex river systems, such as tidal rivers, in which conventional methods of collecting time-series data on suspended-sediment concentration (SSC) and water discharge are not feasible. Although ADCPs are not designed to measure SSC, ADCP data can be used as a surrogate under certain environmental conditions. However, the software for such computation is limited, and considerable post-processing is needed to correct and normalize ADCP data for this use. This report documents the sampling design and computational procedure used to calibrate ADCP measures of echo intensity to SSC and water velocity to discharge in the computation of suspended-sediment discharge at the study site on the Hudson River near Poughkeepsie, New York. The methods and procedures described may prove useful to others doing similar work in different locations; however, they are specific to this study site and may have limited applicability elsewhere.

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