Evidence for Organic Film on an Impervious Urban Surface:  Characterization and Potential Teratogenic Effects

Abstract

Chemical constituents of an organic film collected from an impervious urban surface, namely the exterior surface of windows, have been characterized. The organic portion of this film, that ranged in thickness from 11 to 100 nm, constitutes a previously unrecognized site for exchange of semivolatile organic contaminants in urban environments. The concentrations of total n-alkanes, total polycyclic aromatic compounds (PAH), and total polychlorinated biphenyls (PCB) ranged from 1010 to 22 500, 900 to 62 100, and 8 to 5820 ng/m2 of window surface, respectively. Whereas concentrations varied, the patterns of chemical and congener abundance were similar among samples. Alkanes were derived from mainly biogenic sources, while the PAH showed a weathered pattern and PCB congener patterns generally indicated an enrichment in higher chlorinated congeners. Film-to-air partition ratios, K FA, were calculated for selected PAH and PCB congeners and were comparable to reported values of octanol−air partition coefficients, K OA, suggesting that gas-phase compounds partition into this organic film. Potential biological effects of an organic film extract were evaluated using zebrafish embryo assays. Incubation at a concentration of 270 ppb ΣPAH plus 420 ppb ΣPCB showed 100% lethality, while concentrations 3−10 times lower produced a dose-dependent syndrome of abnormalities including cardiovascular, hematopoietic, neural crest-related, and behavioral defects.

Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols

“…SAMs formed by reaction of trichloroalkylsilanes on SiO x surfaces, for example on the thin oxide layer on silicon, may be particularly relevant to reactions of organic compounds on dust and on building materials for which silicates can be major components. 208,[238][239][240][241][242][243][244] Another advantage is that silicon crystals are readily available which can be used to make real-time measurements of the oxidation of SAMs attached to their surface using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. In one study, 221 ozonolysis of terminal alkene SAMs with 3-and 8-carbon atoms was observed to give CQO groups as products as expected, at least a portion of which were in the form of carboxylic acids that could be converted to carboxylates by reaction with gaseous NH 3 .…”

Distribution and congener profiles of short-chain chlorinated paraffins in indoor/outdoor glass window surface films and their film-air partitioning in Beijing, China

“…Some researchers have noted that organic films can be formed through partitioning on these surfaces and have a significant influence on the transportation and fate of SVOCs in urban environments (Law and Diamond, 1998;Diamond et al, 2000;Gingrich et al, 2001). The deposition of SVOCs and wash-off make organic films both a sink and source for various pollutants.…”

Polycyclic aromatic hydrocarbons on indoor/outdoor glass window surfaces in Guangzhou and Hong Kong, south China

“…A thin organic film could develop on urban impervious surfaces from the condensation of air contaminants. The few existing studies on this topic show that organic films can range from 11 to 1000 nm in thickness and that the proportion of organic matter ranges from approximately 5e20% (Diamond et al, 2000;Liu et al, 2003b;Wu et al, 2008). Due to the high proportion of organic content of the film, the concentrations of semi-volatile organic compounds (SVOCs) are high on the artificial surfaces of urban areas (Butt et al, 2004;Gingrich et al, 2001;Liu et al, 2003a).…”

“…Due to the high proportion of organic content of the film, the concentrations of semi-volatile organic compounds (SVOCs) are high on the artificial surfaces of urban areas (Butt et al, 2004;Gingrich et al, 2001;Liu et al, 2003a). SVOCs can accumulate in organic films through the exchange and partitioning of gasphase chemicals with air and/or the direct deposition of particlephase compounds (Diamond et al, 2000;Law and Diamond, 1998;Liu et al, 2003b). Thus, organic films could affect the surface-air exchange and the residence time of SVOCs in urban environments (Priemer and Diamond, 2002).…”