Chemical speciation and environmental health risk of heavy metals in fine particulate matter

The respirable fraction of ambient particulate matter with aerodynamic diameter less than 2.5μm, (PM2.5) collected at a rural site in Agra during September, 2015 to February, 2016 were characterized with respect to 8 metals (Cd, Cr, Fe, Mn, Ni, Pb and Zn) by Inductively coupled plasma-atomic emission spectroscopy. The metals were chemically fractionated by sequential extraction in order to determine their mobility, bioavailability and health risk. The mobility of the metals were found in the following order: Ni (80%) > Pb (72%) > Zn (65%) > Mn (63%) > Cu (57%) > Cd (51%) > Fe (44%) > Cr (40%). The contamination factors (Cf) and risk assessment code (RAC) were calculated to assess the environmental risk of heavy metals. Due to the exposure to Cd, Cr (VI) and Ni present in air, the total incremental lifetime cancer risks (ILCR) were 2.27×10
^-5
, 1.56×10
^-5
and 5.71×10
^-6
, respectively showing their potential risk to human beings.