Heavy metal contamination of soil in mechanic workshops

Abstract

The distribution of metal in soil from mechanic workshops around Zaria, Nigeria (Latitude: 11° 4' 0 N, Longitude: 7° 42' 0 E) was studied. The types of mechanic workshops considered were motorcycle, motorcar, truck/lorries and generator set. The soils were sampled in August 2010. The results indicated that there was an increase in the metal content of soil in all types of mechanic workshops. The heavy metal (nickel, copper, zinc, lead and arsenic) content of the soil was compared with recommended limits. The percentage composition of some of the heavy metals, in many of the samples, were found to be in excess of the considered set limit, particularly for lead for which the percentage of soil samples analyzed from motorcycle, motorcar, truck/lories and generator set mechanic workshops in excess of the considered recommended set limit was found to be 88.89, 100, 100 and 100% respectively. 11.1% of all the samples analyzed were found to contain arsenic in excess of recommended limit. Statistical analysis of the heavy metal content (one-way analysis of variance) indicated that the Zn and Pb contents of soil from mechanic workshops were not functions of the workshop type (P > 0.05) but the nickel and copper contents were found to be dependent on workshop type (P < 0.05).