Heavy metal accumulation related to population density in road dust samples taken from urban sites under different land uses

- Road dust increased along with city growth and its dynamics.
- The commercial sector showed the highest concentrations of heavy metals.
- The presence of Zn, Pb and Cu in the three sectors is noteworthy.
- Road dust might cause a number of negative environmental impacts.

Soil pollution is a key component of the land degradation process, but little is known about the impact of soil pollution on human health in the urban environment. The heavy metals Pb, Zn, Cu, Cr, Cd and Ni were analyzed by acid digestion (method EPA 3050B) and a total of 15 dust samples were collected from streets of three sectors of the city with different land uses; commercial, residential and a highway. The purpose was to measure the concentrations of heavy metals in road sediment samples taken from urban sites under different land uses, and to assess pollution through pollution indices, namely the ecological risk index and geoaccumulation index. Heavy metals concentrations (mg/kg) followed the following sequences for each sector: commercial sector Pb (1289.4) > Cu (490.2) > Zn (387.6) > Cr (60.2) > Ni (54.3); highway Zn (133.3) > Cu (126.3) > Pb (87.5) > Cr (9.4) > Ni (5.3); residential sector Zn (108.3) > Pb (26.0) > Cu (23.7) > Cr (7.3) > Ni (7.2). The geoaccumulation index indicated that the commercial sector was moderately to strongly polluted while the other sectors fell into the unpolluted category. Similarly, using the ecological risk index the commercial sector fell into the considerable category while the other sectors classified as low risk. Road dust increased along with city growth and its dynamics, additionally, road dust might cause a number of negative environmental impacts, therefore the monitoring this dust is crucial.

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