G01_P05

Source apportionment of atmospheric and sedimentary PAHs from Kolkata, India by using compound-class-specific radiocarbon analysis (CCSRA)

Kumata H¹, Uchida M², SAHA M^3,4, Mantoku K², Kobayashi T², Okuda T⁵, Shibata Y^2,6, Takada H³

¹Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan, ²National Institute for Environmental Studies, Tsukuba, Japan, ³Tokyo University of Agriculture and Technology, Fuchu, Japan, ⁴Now at National Institute for Oceanography , , India, ⁵Keio University, Yokohama, Japan, ⁶Tokyo University of Science, Tokyo, Japan

Asia is one of the most important source regions for short-lived climate pollutant (SLCP), to the atmosphere. For polycyclic aromatic hydrocarbons (PAHs), known as major mutagens in atmospheric aerosols, Asian megacities have the highest levels across the globe.

We conducted compound-class-specific radiocarbon analyses (CCSRA) for surface sediments and aerosols collected in city center of Kolkata. Surface sediments were collected from city canals using a grab sampler. The study site was chosen because the preliminary survey showed it has extremely high-level contamination. Collected sediments were roughly sectioned on-site and approximately upper half (0-7 cm, depth from the surface of the sediment) was used. The ƒC values of sedimentary PAHs in Kolkata city canal sediments ranged 0.056 to 1.0 in the north canal and 0.078 to 0.080 in the south canal, indicating strong influences (i.e., >90%) from fossil fuel combustions. Combined with molecular fingerprinting study, relative contribution from coal combustion in brickyards to sedimentary PAHs was estimated to be >50%. As monsoon driven runoff events flush canals every year, this may portray the input of particle-borne pollution over the last few years. Based on the results obtained, we discuss the importance of contemporary sources of combustion-derived PAHs in Indian Mega city.