Polychlorinated dioxins and furans from the World Trade Center attacks in exterior window films from lower Manhattan in New York City

Samples of ambient organic films deposited on exterior window surfaces from lower Manhattan and Brooklyn in Now York City were collected six weeks after the terrorist attacks at the World Trade Center (WTC) on September 11, 2001 and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Total tetra- through octa-CDD/F concentrations in window films within 1 km of the WTC site in lower Manhattan ranged up to 630 000 pg/m(2) (estimated as a mass concentration of ca. 1 300 000 pg/ g) and a maximum toxic equivalent (TEG) concentration of 4700 TEQ/m(2) (ca. 10 000 pg TEQ/g). Measurements at a background site 3.5 km away in Brooklyn showed lower concentrations at 130 pg TEQ/m(2) (260 pg TEQ/g). Ambient gasphase PCDD/F concentrations estimated for each site using an equilibrium partitioning model suggested concentrations ranging from ca. 2700 fg-TEG/m(3) near the WTC site to the more typical urban concentration of 20 fgTEQ/m(3) at the Brooklyn site. Multivariate analyses of 2,3,7,8substitued congeners and homologue group profiles suggested unique patterns in films near the WTC site compared to that observed at background sites in the study area and in other literature-derived combustion source profiles. Homologue profiles near the WTC site were dominated by tetra-, penta-, and Hexa-CDD/Fs, and 2,3,7,8substituted profiles contained mostly octa- and hexachlorinated congeners. In comparison, profiles in Brooklyn and near mid-Manhattan exhibited congener and homologue patterns comprised mainly of hepta- and octa-CDDs, similar to that commonly reported in background air and soil.