Heavy metal contamination and health risk assessment of road dust from landfills in Dhaka-Narayanganj, Bangladesh

In the recent years, air pollution has become an alarming issue for human health in many rapidly growing megacities including Dhaka and Narayanganj. Herein, pollution status and health risk have been assessed by the road dusts collected from landfills in Dhaka and Narayanganj through determination of heavy metals including Pb, Cd, Cr, As, Cu, Ni, Zn and Mn using atomic absorption spectroscopy. The collected dust samples have been grouped into three sizes, for example, <300−>150, <150−>75 and < 75 μm, to assess the degree of heavy metal accumulation in the dust particles. The dust particles were accumulated with high concentrations of Pb and As at Matuail landfills, whereas Cd, Cr, Zn, and Mn concentrations were highest at Narayanganj landfills. The finer particles, for example 75 μm, accumulated substantial concentrations of heavy metals. Pollution index and pollution load index (PLI) results revealed that all of the sites were deteriorated by Pb, Cd, Cu, Zn and Ni. PLI results exhibited that the quality of the Matuail landfill area was severely deteriorated. In terms of non-carcinogenic health risk, the values of hazard quotient for ingestion were greater than those for inhalation and dermal pathways. For adult groups, hazard index values for the Matuail landfills and medical waste incineration sites were greater than 1, while for the children groups, the values for the same areas, including the Narayanganj landfills, were also larger than 1. These values were at least one order of magnitude higher for the children groups than for the adult groups. Given the results, it would be reasonable to draw the conclusion that non-carcinogenic health risks for children may be more prevalent in the relevant areas.