Heavy metal pollution of ambient air in Nagpur City

摘要

Heavy metals released from different sources in urban environment get adsorbed on respirable particulate matter less than 10 μm in size (PM_(10)) and are important from public health point of view causing morbidity and mortality. Therefore, the ambient air quality monitoring was carried out to study the temporal and special pattern in the distribution of PM_(10) and associated heavy metal content in the atmosphere of Nagpur, Maharashtra State, India during 2001 as well as in 2006. PM_(10) fraction was observed to exceed the stipulated standards in both years. It was also observed that minimum range of PM_(10) was observed to be increased in 2006 indicating increase in human activity during nighttime also. Six heavy metals were analyzed and were observed to occur in the order Zn > Fe > Pb > Ni > Cd > Cr in 2006, similar to the trend in other metro cities in India. Lead and Nickel were observed to be within the stipulated standards. Poor correlation coefficient (R~2) between lead and PM_(10) indicated that automobile exhaust is not the source of metals to air pollution. Commercial and industrial activity as well as geological composition may be the poten- tial sources of heavy metal pollution. Total load of heavy metals was found to be increased in 2006 with prominent increase in zinc, lead, and nickel in the environment. Public health impacts of heavy metals as well as certain preventive measures to mitigate the impact of heavy metals on public health are also summarized.