Assessment On Heavy Metal Pollution Characteristics And Human Health Risk Exposure Over Ambient PM_2.5 In Campus

PM2.5is a detectable contaminated weather phenomenon with low visibility caused byparticles and gas pollutants. Its serious impact on ecology, climate and economy has causedmany environmental and health effects, which has given rise to the social and widespreadpublic attention.In this paper, to understand the north campus of atmospheric PM2.5pollution features andthe characteristics of heavy metal pollution and its harm, we set Tianjin Nankai university forsampling points and collected PM2.5samples in2012June, August, October and Decemberand2013January respectively.Using weight method to analyze PM2.5concentrations andICP-MS to analyze heavy metal content in PM2.5values. Using enrichment factor method andprincipal component analysis to analyze general source of heavy metals in PM2.5.Usingcumulative index, potential ecological risk assessment and health risk assessment for theheavy metal in PM2.5hazard evaluation.The main results are as follows:(1) Campus PM2.5mass concentration in2012June, August, October, December and2013January are:73.14μg·m-3,49.09μg·m-3,69.96μg·m-3,100.18μg·m-3and105.81μg·m-3.Time variation law of PM2.5mass concentration from big to small in turn is December,January, June October and August, which is in accordance with the change rule of Tianjinnormal about PM2.5mass concentration.(2) Analyzing campus PM2.5Heavy metal (Cr, Ni, Cu, Zn, As, Cd, Pb, Hg, Mn) detection,it is concluded that the order of concentration is:0.02μg·m-3,0.01μg·m-3,0.17μg·m-3,0.30μg·m-3,0.0013μg·m-3,0.01μg·m-3,0.1μg·m-3,0.000027μg·m-3,0.1μg·m-3. The order isZn>Cu>Pb>Cr>Ni>Mn>Cd>As>Hg. Nine kinds of Heavy metal elements are beyond thenormal concentration in the ambient air quality standard (GB3095-2012).(3) The enrichment factor method results show that the enrichment factor of the Cu、Zn、Cd、Pb four elements is more than10. These elements less affected by soil dust, mainly comesfrom artificial source contribution, is a typical pollution elements.(4) The result of principal component analysis shows that the coal pollution, motorvehicle exhaust, and domestic pollution sources are the main source of heavy metal pollutionin the campus PM2.5.(5) From the perspective of the calculation results in cumulative indext, the order frombig to small of heavy metal accumulation in PM2.5index is Cd> Cu> Pb> Zn> Ni> Cr>As> Hg> Mn. Cr, Ni, As, Hg, Mn five kinds of heavy metal accumulation index is less than0,that is,no actual pollution. Cd reached high levels of pollution, Cu, Zn and Pb with amoderate pollution.(6) The potential ecological risk assessment results that campus PM2.5pollution of heavymetals in the level of a category C (harm). Order of each element and ecological damage isCd> Cu> Pb>Zn> Hg> Ni> As> Cr> Mn. The Cd teached to class B. (7)9kinds of heavy metals by breathing on the annual average excess risk of exposurepopulation size in the order: As>Cd>Cr>Ni>Pb>Mn>Cu>Zn>Hg. Four kinds of carcinogenicheavy metals through breath way to the average excess risk of exposed population is between1.14×10-8and7.8×10-6, which is beyond all people acceptable risk level (10-6/year). Fivekinds of carcinogenic heavy metals through breath way to the average excess risk of exposedpopulation is between4.56×10-13～4.8×10-9,which is lower than the population of acceptablerisk level (10-6/year).