Assessing the potential risks of industrial soil of highly industrialized and less cities on plant growth

Heavy metals are due to accumulate over time in the soils thereby act as a sink reservoir from which toxicants are released to the groundwater and eventually for the uptake by plants. This study was aimed at investigating the heavy metal concentrations and the consequent effects on two common food crops (maize and cowpea). Three sites of ten soil samples at two points (0 and 50 meters apart) were collected with two samples from various manufacturing area of: Sango-Otta (highly industrialized), Oluyole industrial estate (less industrialized) and Saki with no industrial activities. Suitable spot nearest to the production area on the site were located and fifty meters away from the first site. The top soil layer was scrapped off using a shovel, and a portion of soil was scooped inclining the shovel beneath the earth. Soil samples were collected from depths of one feet and four feet respectively. The sample were put in a clean plastic container weighing about 200 g and was subsequently air dried and transported to the laboratory for test. Concentrations of heavy metals were found to be very high in the highly industrialized than in the less industrialized cities. Conversely, the F-calculated value was 2.906 > 0.096b which was significant in soil samples of post-planting in cowpea, and the F-calculated value was 1.021 > 0.319b F-Sig for the soil samples post planting in Zea mays. As reported in this study, the concentration of heavy metals impacted on the field performance of the selected crops. The concentration of heavy metals in the soil should be continuously monitored by farmers before planting especially those in the highly industrialized cities.