Analysis of street dust for heavy metal pollutants in Mubi, Adamawa State, Nigeria

Abstract

This study is aimed at determining the elemental concentrations of heavy metal pollutants that may be present in street dust samples in Mubi, Adamawa state, Nigeria. Dust samples were collected in mechanical workshops (MWK), motor parks (MPK), market areas (MKA), roundabouts/highways (RHW) and residential areas (RDA). The dust samples were digested using aqua regia digestion method and Flame Atomic Absorption Spectrophotometer was used for the elemental analyses. The variation in concentration of most of the heavy metals determined from different sites decreases in an order represented as MWK >MPK >MKA >RHW > RDA. The heavy metals showed a variation that indicated that Fe >>> Zn >> Pb >> Cu >> Cd, Iron (Fe) had the highest concentration in all the sampling areas with range of 5330.50 ± 499. 80 − 24100.00 ± 968.20 µg/g. A lower value was observed for Cd with respective range of 0.59 ± 0.19 − 1.33 ± 0.36 µg/g. Cobalt and Selenium were not detected in all the samples. Statistical analysis by ANOVA and t-test showed a significant difference (P<0.05) between the elements determined. This suggested that, the heavy metal pollutants in street dust samples of Mubi did not originate from common anthropogenic sources becausesome heavy metals are soil derived. Probably automobile emission, welding of metal and exhaust from generators may be the major sources of the elements. Key words: Metal pollution, dust, sampling sites, automobile emission, atomic absorption spectrophotometer, toxic substances, concentration.