POPs in the Mongolian environment

An environmental and human monitoring project analyzing the persistent organic pollutants (POPs) listed in the annexes of the Stockholm Convention on POPs was implemented in Mongolia with sampling activities from 2017 until 2019. In support of the global monitoring plan implementation, a total of 51 samples were analyzed for POPs whereby 23 POPs were detected frequently. Two POPs, endrin and hexabromobiphenyl (PBB 153), were not quantified in any of the samples; toxaphene was found only twice in air samples; and dicofol, pentachlorophenol, and short-chain chlorinated paraffins were analyzed only in one human milk sample. Most results were for perfluorooctanoic acid (PFOA, 32 of 43 samples) and perfluorooctanesulfonic acid (PFOS, 31 of 43 samples). With respect to detection frequency, dioxin-like polychlorinated biphenyls (dl-PCB) were detected in 100% of the samples analyzed (N = 28). On scale, highest amounts were found in soil samples, almost 30 000 ng/g for lindane, more than 13 000 ng/g for α-hexachlorocyclohexane (α-HCH), and almost 10 000 ng/g for dichlorochlorodiphenyltrichloroethane (DDT) and its transformation products. The soil and ambient air samples were the drivers towards highest values in the abiotic samples, due to the presence of legacy POPs such as DDT, indicator PCB, HCHs but also hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz). Concentrations of dioxin-like POPs were low in general as were the perfluorinated substances (PFAS). With respect to brominated flame retardants, the presence of hexabromocyclododecane in air samples was surprising. At present, the analytical capacity to analyze POPs in various matrices under the global monitoring plan for POPs is being set-up to strengthen future environmental monitoring activities in Mongolia.