Analysis of heavy metals’ contamination in soils and water at automobile junk markets in Obosi and Nnewi, Anambra State, Southeastern Nigeria

Auto junk markets have been observed to be one of the sources of heavy metal pollution in soils and water. The aim of this study is to assess the level of heavy metal pollution within two largest auto junk markets in Nigeria at Obosi and Nnewi, respectively. Twenty-four (24) composite soil samples including the background (control) samples at 0–15 and 15–30 cm depths, and six (6) water samples were randomly collected. Samples were properly digested and subjected to spectroscopic analysis using atomic absorption spectrometer (AAS) for trace metals. Seven selected heavy metals (Fe, Cu, Ni, Cr, Zn, Mn, and Pb) were analyzed in three replicates. The results revealed that trace metals’ concentration (ppm) in 0–30 cm depth are well above the background values with Ni in excess of international standard. Metal enrichment is in the order of Ni > Fe >> Zn > Cu > Mn > Pb > Cr. Results of heavy metals obtained from the water samples revealed that Mn, Fe, Cu, and Ni are in excess when compared with the World Health Organization (WHO 2009 ) and Nigerian Standard for Drinking Water Quality (NSDWQ 2007 ) standards for drinking water. The pollution load index and contamination factor reveals that the soil around the automobile junk markets are at various stages of pollution with heavy metals, ranging from slight contamination to severe pollution. Water around the automobile junk markets are not advisable for domestic uses, as a result of its heavy metal contents, which are connected to the effects of industrial waste accumulation and indiscriminate domestic waste disposal as suggested by the principal component analysis.