ECOTOXICOLOGICAL STUDIES OF QUARRY SITE AND ITS ENVIRONMENT ALONG IRESE, AAYE ROAD, IFEDORE LOCAL GOVERMENT AREA, ONDO STATE

Abstract

Majority of dust produced from quarry site are scattered on soil, farmlands and surface water around the quarry sites which are hazardous to human and the entire environment. The study assessed the ecotoxicological effects of quarry site and its environment. Four samples (soil, water, plant and air) were collected for this research from quarry site and its environment at increasing distance of 50, 100, 150, 200 and 400 m from the quarry processing plant. Soil samples were collected at different depth; 0-15 cm and 15-30 cm. The collected samples were prepared and analysed for their physicochemical properties and minerals using standard methods. Results obtained from the concentration of heavy metals in the soil show that, the concentration of cadmium (Cd) decreased with increase in distance for both topsoil and subsoil. The topsoil has the highest value of 0.08 mg/kg at 0 m and lowest value of 0.02 mg/kg at 400 m which is lower than the control (0.01 mg/kg). The concentration of lead (Pb) was found to be high in most of the samples which show that the soil is contaminated with Pb. The highest value in the topsoil was observed at the distance of 0 m with the value of 1.28 mg/kg and lowest at distance of 400m with the value of 0.60 mg/kg which could be as a result of distance to the quarry operation. The result shows conspicuous high concentration of iron (Fe) in the soil samples compared to other metals. The concentration was found to be highest in topsoil at 0m with the value 221.83 mg/kg and lowest value of 200.17 mg/kg at distance of 400m. The physico-chemical analysis of the ground and surface water shows that most of the parameters (pH, conductivity, acidity, alkalinity, DO, BOD e.t.c) were within WHO permissible limits. The result of concentration of heavy metals in both water and plant samples shows that only cadmium (Cd) and lead (Pb) was above the WHO and FMEnv permissible limits while other metals were below the permissible limits for both the surface and ground water. The pollution load index (PLI) was above >1 at all the distances except for 400 m for both topsoil and subsoil. Contamination factor was found to be highest in cadmium. The highest value was observed at topsoil 0 m and 50 m (8.00 and 6.00 respectively) which indicates very high contamination factor. The result from the air analysis shows that NO2, SO2 and CO concentrations were below instrument detection limit (<0.001 mg/m3). However, measurable values of suspended particulate matter (TSP) were recorded in all the sampling points. The values obtained for 0 m, 50 m, 100 m, and 150 m exceeded the FMEnv (250 μ/m3) and WHO (150-230 μ/m3) permissible limit.