Oxides and Heavy Metals Concentration around a Cement Plant at Yandev, Central Nigeria

Abstract

Aims: To determine the level of concentration of oxides (chemicals) and heavy metals in 6 soil samples. To further compare the results with acceptable soil quality standards to ascertain the status of soil quality within the study area. Study Design: Collection and analyses of soil samples from the vicinity of Dangote Cement factory, Yandev. Place and Duration of Study: A total of 6 soil samples were collected: using a 2-kilometer interval, five samples were collected within the study area starting from the center of the Cement factory while the sixth soil sample was collected from a Control Community (Tarhembe) located 12 kilometers from the Cement factory in a part of Benue State, Nigeria. The total of six soil samples was collected in May 2013. Methodology: Laboratory analyses were conducted for 27 soil parameters. Mean, maximum and minimum values and standard deviation, coefficient of determination (R2) and ANOVA for all 27 parameters was derived using SPSS Version 15 software. Using guidelines applied in various soil quality studies, the concentration levels of pollutants in soils samples were determined for all 27 parameters to establish whether or not their level of concentration at the study area constitute significant health problems. Results: The mean values indicate high concentration levels above permissible limits for Iron (III) oxides, Calcium oxides, Magnesium oxides, Sodium oxides and Potassium oxides. Although the permissible limit values for other oxides could not be obtained, their mean concentration values appear to be generally higher in all soil samples closer to the factory than the Control sample. Heavy metals content in the 6 soil samples indicate that the mean values recorded for Iron, Lead, Manganese, Zinc, Copper and Conductivity exceed the permissible limits while the mean values for Organic Carbon, Calcium, Magnesium and pH occur below the permissible limit. Furthermore, the control sample reveals concentration below the permissible limits for Organic Carbon, Lead, Calcium and Magnesium, whereas samples 1, 2, 3, 4 and 5 (2km, 4km, 6km, 8km and 10km from factory) contain concentration levels above the permissible limit. Conclusion: Analysis indicates that the soils are polluted with some oxides and heavy metals originating from limestone mining and cement production. Therefore, the study concludes by recommending ameliorative strategies including consistent monitoring of the soil quality status, adoption of specialized technologies to curtail the rate of plume emission from stacks and the development of a phased environmental management plan (EMP) and/or impact mitigation plan (IMP) by local planning authorities.