CONDUCTING ENVIRONMENTAL FORENSICS IN DYNAMIC, HIGHLY URBANIZED ESTUARINE SYSTEMS: LESSONS LEARNED FROM INVESTIGATING THE IMPACT OF THE WORLD TRADE CENTER ATTACK ON THE SEDIMENTS OF NEW YORK HARBOR

The September 11, 2001 terrorist attack on the World Trade Center (WTC) in New York City introduced large amounts of ash and debris over a wide area including New York Harbor (NYH). Previous research has identified a “fingerprint” for the WTC ash. Ash materials were shown to have a bulk elemental, organic, and stable isotopic signature consisting of: 1) enriched Ca, S, Sr, Cu, Zn, Pb concentrations from construction materials; 2) elevated Polybrominated Diphenyl Ether (PBDE) concentrations from fire-retardant materials; 3) constant relative amounts of specific Polycyclic Aromatic Hydrocarbons (PAH) occurring in distinct mass fractions; and, 4) a specific Sr isotope ratio (Sr-87/Sr-86). WTC ash and debris was also determined to have an identifiable textural composition consistent with the construction materials from which it was derived. The WTC fingerprint could be used to quantify and qualify the impact of the event on the sediments of the local estuarine system. Results from past and ongoing work provide a practical example that highlights challenges faced in conducting sensitive environmental/geologic forensics work in dynamic, highly urbanized estuarine systems like NYH. These challenges include: 1) identifying and spatially quantifying areas of likely benthic impact and preservation; 2) resolving event-specific chemical and textural signatures against an anthropogenically impacted and heterogeneous background; 3) determining the temporally variable fate of the introduced ash and debris in a highly dynamic estuarine system; and, 4) qualifying the impact of the event on an already highly altered benthic environment. Lessons learned should aid in the conduct of future environmental forensics work in estuarine and coastal systems; specifically including the development of an integrated geophysical and geochemical approach to investigate sediment accumulation patterns and transport.