Numerous anthropogenic chemicals are produced in manufacture and household applications every year, during which emission into the environment is inevitable. Nevertheless, information on potential environmental risks and biological effects of a majority part of the chemicals is still a mystery. ToxCast program has consequently been implemented for the purposes of ranking and prioritizing chemicals by developing toxicity prediction models with a subset of chemicals acted as the training set. A total of 1060 unique compounds were contained in the Phase I and Phase II catalogues, which are prior contaminants in the environment. In recent years, airborne fine particulate matter (PM2.5) pollution has become an urgent environmental issue due to its adverse effects to human health. However, analysis of PM2.5 components is still challenging. Currently recognized organic pollutants are merely biogenic secondary organic aerosol precursors, conventional persistent toxic substances, and brown carbon components. PM2.5 samples were collected using glass filters by a low-volume air sampler in 2016. A modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for sample extraction and purification. Data acquisition was achieved by a method utilizing ultrahigh performance liquid chromatography coupled to Orbitrap Fusion mass spectrometer. A comprehensive suspect screening workflow including feature identification, matching, filtering and candidates structure confirmation was developed to determine the presence of ToxCast chemicals. Presence of a total of 142 ToxCast chemicals and relevant analogues were confirmed in the PM2.5 samples, covering broad categories such as plasticizers (e.g. phthalates, carboxylates), pharmaceuticals (e.g. nicotine, caffeine), surfactants (e.g. perfluoroalkyl acids, sulfates), flame retardants (e.g. organophosphate esters), pesticides (e.g. buprofezin, diethyltoluamide), bactericides (e.g. metalaxyl, parabens) and so on. All chemicals were identified with communicating confidence levels (CL) &gt; 3 (36 compounds with CL 1; 57 compounds with CL 2a; 14 compounds with CL 2b; 35 compounds with CL 3). Correlations were further found between temporal trends on instrumental responses and environmental indices (temperature, humidity and mass of PM2.5).

High-throughput identification and prioritization of ToxCast chemicals in airborne fine particulate matter

2019 Spring National Meeting

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