Organochlorine pesticides and polychlorinated biphenyls in air, grass and yak butter from Namco in the central Tibetan Plateau

Limited studies on bioaccumulation of persistent organic pollutants (POPs) along terrestrial food chains were conducted. The food chain air–grass–yak (butter) in the pasture region of Namco in the central Tibetan Plateau (TP) was chosen for study. The air, grass and butter POPs in the TP were at the lower end of the concentrations generally found around the globe. HCB was the main pollutant in air and butter. Besides HCB, β-HCH and p,p′-DDE were the other major compounds in butter. Along the food chain, DDTs and high molecular weight PCB-138, 153 and 180 had higher Biological Concentration Factor values. The air–butter transfer factors of POPs were derived and demonstrated the practical advantage in predicting the atmospheric OCPs and PCBs to the TP. This study sheds light on the transfer and accumulation of POPs along the terrestrial food chain of the TP. - Highlights: • Air, grass and butter POPs in the Tibetan Plateau (TP) were at the lower end of the global levels. • The pasture of the TP was found to be a "sink" of DDTs. • Bioaccumulation of OCPs and PCBs happened along the food chain: air–grass–yak. • The TF_A:B was tested to be an excellent tool to predict air OCPs and PCBs in the TP. - Transfer and bioaccumulation of OCPs and PCBs happened along the terrestrial food chain: air–grass–yak (butter)