Chemosphere ( IF 5.778 ) Pub Date : 2020-08-01 , DOI: 10.1016/j.chemosphere.2020.127700 Balasubramanian Prithiviraj; Ajay Taneja; Paromita Chakraborty
Recent studies from India reported polychlorinated biphenyls (PCBs) associated with incomplete combustion processes. In this study we have monitored atmospheric PCBs in Agra, a non-metropolitan city of northern India. During first month of summer and winter of 2017, polyurethane foam based passive air sampler (PUF-PAS) was deployed at each of 14 locations across urban, suburban and rural transects and one background site. Range of Σ25PCBs varied between 25-1433 pg/m3 (Avg±Stdev: 460±461) in summer and 26-205 pg/m3 (Avg±Stdev: 106±59) in winter. Mean Σ25PCBs concentration, showed an urban > suburban > rural trend in summer while, in winter a rural > urban > suburban trend was observed. PCB-52 was the dominant congener and after excluding this outlier no significant differnce was observed between summer and winter PCB concentrations. Using a combination of K-means cluster and principal component analysis (PCA) four major source types were identified. Open burning source accorded 80% of atmospheric PCBs majorly indicator PCBs in Agra while the remaning 20% was contributed by atmospheric transport, petrogenic combustion and biomass burning. From the five days back trajectory air mass it can be suggested that atmospheric transport from the hotspots.resulted in a minor percentage of dioxin like PCBs in Agra. Maximum TEQs was accorded by PCB-77 (30%) and it is consistent with previous observations from Agra. Levels observed in the current study are well within public health guideline based on inhalation unit risk (10 ng/m3) and United States Environmental Protection Agency’s regional screening level high risk tier (4.9 ng/m3) for ambient air.