The Hudson River PCB Problem Ben Jewell Przemyslaw Bosak

PCB Intro Molecular structure: Characteristics Sources Disposal Two benzene rings linked by a single bond Chlorine replacement of some Hydrogen atoms Characteristics Nearly insoluble in water Difficult to burn Low vapor pressure Good electrical insulators Sources Synthetic, used as a coolant fluid US production ended in 1977, still in use in transformers Disposal Incineration

PCBs in the Environment Where does it go? Deposition in river/lake sediments Enters food stream, bio accumulation Volatilization Life span Do not readily degrade Can exist in environment for decades

PCB Health Effects Not acutely toxic to humans Chloracne Cancer most common sympton of organochlorine exposure Disfiguring, painful analog to acne Cancer the types of PCBs likely to be bioaccumulated in fish and bound to sediments are the most carcinogenic PCB mixtures found through animal and exposure studies Immune System increasing risk of non-Hodgkins lymphoma Neurological learning deficits and changes in activity associated with exposures to PCBs most strongly associated with newborn children Reproductive decreased birth weight significant decrease in gestational age Exposure studies

Hudson River History General Electric: 1950s, 60s and 70s Uses Capacitors, power transformers Discharge Two capacitor manufacturing plants released between 209,000 and 1.3 million pounds Leaking devices

Clean Up Efforts Past Clean up Dredging of 180,000 cubic yards of contaminated sediments in 1977-78 Capping of remnant deposits with a geosynthetic clay liner and a 2-foot layer of soil, Stabilization of river banks with rock Continuous monitoring of PCB level in the river

Hudson River Now Peak PCB level in 1991 Clean up efforts lowered the concentration of PCB in the water and have kept it at pre-1991 level Catch-and-release fishing allowed

What is next? Dredging of 2.65 million cubic yards of PCB-contaminated sediments using environmental techniques to minimize resuspension of sediments Covering dredged areas with one foot of clean soil to isolate residual PCBs Restoration of aquatic vegetation Monitoring system recovery

Aquatic Chemistry Implications Dredging Disruption to aquatic system Increased turbidity Release of trapped minerals and nutrients Bioaccumulation effects on river fauna Hazardous to health

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