Assessment of foliar dusts metals burden as indicators of heavy metals contamination in Kano metropolis, Nigeria

Abstract

ABSTRACT Plants have been used as biological filters by taking advantage of their capacity to remove dust and heavy metals from the air, which make them effective biomonitors to detect the presence of these metals even at trace levels. The present study was aimed to assess the levels of heavy metal in foliar dust of some selected urban trees along the roadside in Sauna Kawaji, Magwan, Kwanar Ganduje, and Nassarawa GRA of Kano Metropolis. From each sample site, leaf samples of neem trees (Azadirachta indica) were randomly collected along the roadside. The leaves were processed, digested and analysed by atomic absorption spectrometry. From the results, site variation showed that Zinc, Manganese, and Cadmium had the highest levels of 0.019, 0.137 and 0.0039 mg/L at Magwan and Kwanar Ganduje, respectively. In the evening hours, zinc, manganese and cadmium had the highest levels of 0.022, 0.140, and 0.002 mg/L at Magwan, Sauna Kawaji and Kwanar Ganduje, respectively. However, lead was not detected in all samples. Manganese was found to be the highest from all sampling sites, while cadmium had the least. However, the levels of the analysed metals were below the permissible limits of WHO and EPA. Therefore, foliar dust contained heavy metals in relative amount, which might be a cause of concern for environmental issues and could serve in environmental monitoring.