- Количество слайдов: 19
A Hazardous Waste Site PCB Contamination
Polychlorinated Biphenyls (PCBs) n n Man-made class of oil-like chemicals used in the manufacture of electrical equipment due to the molecules’ insulating properties. Banned from manufacture in the US in 1977.
PCBs in the Environment Do not readily break down and thus persist in the environment n Stick to particles and bottom sediments in water n Build up in fatty tissues of animals due to their fat-soluble (lipophilic) properties (bioaccumulation) n Ingested by aquatic organisms and increase in concentration through food chain (biomagnification) n
Hazardous Waste: How did it get there?
NPL Site: Ward Transformer about 1966 late 1980’s
NPL Site: Ward Transformer n n n Ward Transformer in Morrisville, NC reconditioned electrical transformers from 1964 -2006. Added to EPA’s National Priority List in 2003 due to discovery of PCB contaminated fish tissue, sediment and soil resulting from facility operations. Emergency Removal Action completed in 2011; approximately 420, 000 tons of PCB contaminated soil was treated or removed.
Excavation and Testing of Soils at the Ward NPL site
Soil for stockpiled for thermal desorption unit ([PCB] > 50 ppm)
Golder Associates 420, 000 tons of soil treated or removed from the Ward site.
One Site: Two Remediation Areas n Removal Action Area includes the Ward Transformer facility and immediate surrounding areas (OU-2). n n n Emergency Removal Action completed in 2011. EPA is conducting a feasibility study for OU-2. Areas down gradient from the Ward Transformer facility (OU-1). n The remedial design for OU-1 is ongoing.
Down Gradient Contamination
Down Gradient Contamination EPA proposed remediation alternatives in August 2007. n Public comments were accepted through early October 2007. n In Sept 2008, the EPA selected a clean up plan. n
Pre-Clean Up n n Sampling of sediment and soil prior to digging. Doing an endangered mussel evaluation study.
Clean Up Plan n n Digging up sediment and soil from Reaches B, C and D and lower Brier Creek. Disposing of dug-up materials at an off-site facility. Restoring the site and streams to their original states. Using monitored natural attenuation for Brier Creek Reservoir, Lake Crabtree and Lower Crabtree Creek.
Clean Up Plan: Education n n Continuing or enhancing existing North Carolina fish consumption advisories and signs. Starting educational and community outreach programs.
Also… n n n Monitoring of sediment and aquatic plants and animals. Putting institutional controls in place. Conducting Five-Year Reviews.
Protecting Our Water: PCB Contamination at Ward Transformer Watch documentary