A Model of PCB Fate in the Upper Hudson River

详细信息    查看全文

• 作者：John P. Connolly ; Harry A. Zahakos ; Jennifer Benaman ; C. Kirk Ziegler ; James R. Rhea ; and Kevin Russell
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：October 1, 2000
• 年：2000
• 卷：34
• 期：19
• 页码：4076 - 4087
• 全文大小：261K
• 年卷期：v.34,no.19(October 1, 2000)
• ISSN：1520-5851

文摘

A mechanistic model of PCB fate, transport, and bioaccumulation in the Upper Hudson River was developed toprovide a quantitative tool to assess the effectiveness ofnatural recovery and active remediation in reducing PCBlevels in water, sediment, and biota. The fate and transportmodeling, which is the subject of this paper, builds onprevious approaches by using a mechanistic sediment-transport model that describes erosion and deposition withsufficient accuracy to remove the requirement to adjustsediment transport as part of the contaminant calibrationprocess. An additional significant aspect of the modelis the calibration and validation for both the short time scaleof erosion events and the decade-long time scaleassociated with trends in sediment contamination.Themodel demonstrates differences between PCB fate in cohesiveand noncohesive sediments that are important to effortsto reduce perceived human health and ecological risks. Burialdue to the deposition of solids with lower PCB concentrationsis the principal mechanism responsible for the approximately 90% decline in surface sediment PCBconcentrations since the late 1970s. The more moderatedecline seen in noncohesive sediments is due principally tothe movement of PCBs from these sediments to thewater column. The PCB load passing from the UpperHudson River to the tidal Lower Hudson River is attributableto a combination of an external source located near theGeneral Electric facility upstream of the contaminatedsediments and sediments throughout the river. Eliminationof the upstream source will increase the rate at whichPCB levels decline in the cohesive sediments because itwill reduce the concentration of PCBs on depositing particles.It will also immediately reduce the PCB flux to theLower Hudson River by as much as 20% and affect futurereductions as surface sediment PCB levels decline.