Journal Of Tropical Biosciences
Volume No: 11|
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Title: GEOCHEMICAL ASSESSMENT AND DISTRIBUTION OF HEAVY METAL POLLUTION OF SOILS IN THE VICINITY OF DYE PITS, ZARIA CITY, NORTHERN NIGERIA
RAMADAN MURSHIDA1, NAFIU ABDU2 AND SHUAIBU AKPAI ABDULLAHI1
1DEPARTMENT OF BIOLOGICAL SCIENCES, FACULTY OF SCIENCE, AHMADU BELLO UNIVERSITY, ZARIA
2DEPARTMENT OF SOIL SCIENCE, INSTITUTE FOR AGRICULTURAL RESEARCH/FACULTY OF AGRICULTURE,
AHMADU BELLO UNIVERSITY, ZARIA
This study was conducted to evaluate the distribution of elements (Cu, Cr, Pb and Cd) in five representative soils in the vicinity of dye pits, Zaria city, Nigeria. The concentrations of metals in the soils (Pb, Cr and Cd) recorded were at maximum values of 181.57±20.23, 228.57±18.40 and 40.55±5.17 mg kg-1, respectively. However, the concentration of Cu was within acceptable limit of 200 mg kg-1 while concentrations of Pb, Cd, and Cr were above the threshold levels. Enrichment Factor (EF) of the heavy metals in soil showed that EF = 27.33 for Cd, 10.28 for Pb, 1.02 for Cu and 1.76 for Cr) while the Geo-accumulation Index showed that I-geo=6.41 for Cd, 2.75 for Pb,-0.60 for Cu and -0.16 for Cr. The calculated enrichment factor for Cu and Cr were low indicating low contamination while those of Cd and Pb were high indicating high contamination. The high Cd concentration could be related to lithogenic origin of the soil. The geo-accumulation index showed that Cu and Cr were below Zero indicating no case of contamination while Pb and Cd concentrations were above the critical indicating moderately to extremely contamination. These two indices allows for quick referencing on the status of a metal relative to mean soil concentration. However, these indices are based mainly on the total metal concentration in the environment. Analysis of variance with SAS showed that the mean concentration of metals in soil (p<0.05) were significantly different in some locations and no significance obtained in the other locations. This implies that some of the metals were labile and some are held firmly in the matrix of soil.
It could be concluded that the contaminated soil samples in Zaria City showed the presence of high level of metal contamination far from the prescribed limits, toxic in nature and require proper treatment before disposal on land as it is not safe for final release which is also harmful to man and other living organisms which consequently decrease soil fertility and damage food quality.