Assessment of heavy metal content in suspended particulate matter of coastal industrial town, Mithapur, Gujarat, India

Heavy metal concentrations in suspended particulate matter (SPM) were investigated for their distribution and source in the atmosphere of coastal industrial town, Mithapur, Gujarat, India. SPM, at 10 locations covering three seasons, were trapped on glass fibre filters using high volume samplers and quantification of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) was done using Atomic Absorption Spectrometry employing HNO3 based wet digestion. Results show relatively low concentrations of SPM (211.3 to 375.2 μg/m3) compared to National Ambient Air Quality Standard (NAAQS), specified By Central Pollution Control Board (CPCB, India), however, they were 2–3 times higher as compared to reference site. Among the heavy metals Cr, Mn and Pb levels were low, while Ni and Cd found to be exceeding the USEPA standards. The metal levels were also compared with those reported for other rural, coastal, industrial and urban parts around the world. Enrichment Factor analysis indicated that Cd, Zn, Cu, Pb and Ni were highly enriched relative to their crustal ratios (to Fe) and correspond to substantial contribution of anthropogenic source of these metals. The source identification was carried out by principal component analysis by applying a Varimax Rotated Component Matrix.