Arsenic species in electronic cigarettes: Determination and potential health risk

Human exposure to contaminants from electronic cigarettes(e-cigarettes) and the associated health effects are poorly understood.There has been no report on the speciation of arsenic in e-liquid(solution used for e-cigarettes) and aerosols.We report here determination of arsenic species in e-liquids and aerosols generated from vaping the e-liquid.Seventeen e-liquid samples of major brands,purchased from local and online stores in Canada and China,were analyzed for arsenic species using high-performance liquid chromatography and inductively coupled plasma mass spectrometry.Aerosols condensed from vaping the eliquids were also analyzed and compared for arsenic species.Six arsenic species were detected,including inorganic arsenate(iAs~Ⅴ),arsenite(iAs~Ⅲ),monomethylarsonic acid(MMA),and three new arsenic species not reported previously.In e-liquids,iAs~Ⅲ was detected in 59%,iAs~Ⅴ in 94%,and MMA in 47% of the samples.In the condensate of aerosols from vaping the e-liquids,iAs~Ⅲ was detected in 100%,iAsv in 88%,and MMA in 13% of the samples.Inorganic arsenic species were predominant in e-liquids and aerosols of e-cigarettes.The concentration of iAs~Ⅲ in the condensate of aerosols(median 3.27 μg/kg) was significantly higher than that in the e-liquid(median 1.08 μg/kg) samples.The concentration of inorganic arsenic in the vaping air was approximately 3.4 μg/m~3,which approaches to the permissible exposure limit(10 μg/m~3) set by the United States Occupational Safety and Health Administration(OSHA).According to the Environmental Protection Agency's unit risk factor(4.3 × 10~(-3) per μg/m~3) for inhalation exposure to inorganic arsenic in the air,the estimated excess lung cancer risk from lifetime exposure to inorganic arsenic in the ecigarette vaping air(3.4 μg/m~3),assuming e-cigarette vaping at 1% of the time,is as high as1.5 × 10~(-4).These results raise health concerns over the exposure to arsenic from electronic cigarettes.