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Environmental Investigation by Con Edison

Environmental Investigation by Con Edison. Former E115th Street Gas Works. November 13, 2007. Presentation Overview. Former MGP Site History Investigation Activities and Results Next Steps. Manhattan Center for Science and Math. Former E.115 th Street Gas Works (1895 – 1936).

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Environmental Investigation by Con Edison

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  1. Environmental Investigation by Con Edison Former E115th Street Gas Works November 13, 2007

  2. Presentation Overview • Former MGP Site History • Investigation Activities and Results • Next Steps

  3. Manhattan Center for Science and Math

  4. Former E.115th Street Gas Works (1895 – 1936)

  5. Former Gas Works Structures • Coal Yard/Coal Bins • Oil Tanks • Generators • Purifying Houses • Gas Holders

  6. Manufactured Gas Plant (MGP) Substances of Concern • Coal tar • Purifier waste • Volatile organics: benzene, toluene, ethylbenzene, xylene (BTEX) • Semivolatile organics: polycyclic aromatic hydrocarbons (PAHs)

  7. Site Investigation Activities • Indoor air quality assessment conducted in July and December 2002 • Remedial Investigation performed in August and September 2003 • Remedial Investigation Report approved by the NYSDEC in August 2004 • Supplemental Remedial Investigation conducted in August 2004 (on-site) and January 2005 (Harlem River) • Supplemental Remedial Investigation Report approved by NYSDEC in September 2005.

  8. July 2002 Indoor Air Quality Assessment • Purpose: assess potential MGP contamination beneath the school building and its potential impacts on indoor air quality • Scope included: --Indoor air samples from basement and first floor (13) --Soil gas samples from basement and near building (5) --Air samples outside of building (4) --Soil samples from basement and near building (4) --One groundwater sample near building

  9. July 2002 Indoor Air Quality Assessment Results • All indoor air results were within typical background indoor air range; no indication of MGP impacts • Soil gas samples contained elevated VOC levels • Soil and groundwater results indicated presence of subsurface impacts beneath and near school building

  10. December 2002 Indoor Air Quality Assessment • Purpose: evaluate indoor air quality under winter conditions • Scope: 13 indoor air samples from areas sampled in July 2002 • Results: VOCs indicative of cleaning products, gasoline and paint detected in some samples at levels above background; no discernable MGP impacts observed

  11. Remedial Investigation (August 2003- January 2005) • Purpose: delineate subsurface MGP impacts within the school property and off-site • Scope included: ---Indoor air quality assessment (August 2004) ---Soil and groundwater sampling inside and around the school building ---Sediment sampling in the Harlem River

  12. August 2004 Indoor Air Quality Assessment Results • Indoor air quality generally within typical background range; • Low levels of VOCs indicative of cleaning products and gasoline present in some samples; • VOC levels consistent with previous sampling events; no discernable MGP impacts observed.

  13. Remedial Investigation Results • Some organic compounds and metals found in surface soil at slightly elevated levels, however, within typical background range; • MGP residuals (coal tar) found at depths of 6 feet to 42 feet • Elevated levels of MGP constituents detected in groundwater; • MGP impacted sediments found in Harlem River at depths 14 feet to 27 feet below sediment surface.

  14. Community Outreach • Citizen Participation Plan • Fact Sheets and Public Notices at every phase of investigation • Update meetings were held with NYCDOE, school administration, UFT and faculty • Public Meeting for Parents on March 30, 2004 • Internet Content at www.coned.com/publicissues • Toll-Free Hotline 877-602-6633

  15. Community Outreach

  16. Next Steps • Conduct pilot testing of remedial alternatives under consideration. • Finalize Remedial Alternatives Report (draft submitted to NYSDEC, DOE and Mayor’s office in January 2007) • Prepare Remedial Action Work Plan for NYSDEC review and approval • Implement approved remedy following public review and comment

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