Assessment of Heavy Metal Contamination in Irish Potatoes and Soils From an Abandoned Mining Site in Jos-south Using Aas and Xrf Techniques

ASSESSMENT OF HEAVY METAL CONTAMINATION IN IRISH POTATOES AND SOILS FROM AN ABANDONED MINING SITE IN JOS-SOUTH, USING AAS AND XRF TECHNIQUES

Abstract

This research was done to measure the elements concentration in certain Irish potatoes and farming soils in a region that used to be a mining site in Dahwol-vwana village, Jos-south L.G.A., Plateau state, Nigeria. Using an atomic absorption spectrometer, the total heavy metal contents (for samples of Irish potatoes and soil) were determined. It was observed from the soil sample concentration values gotten at the end of the AAS analysis (Pb, ranges from 0.0445-3.9343ppm; Cd, from 0.0086-0.1200ppm and Zn, from 0.0751-39.0302ppm) are higher than the concentration values obtained from control area (Pb- 0.0088ppm, Cd-0.0029ppm and Zn-0.0101ppm), but lesser than the international threshold values (EU:- Pb-300ppm, Cd-3.0ppm and Zn-300ppm. USA: 300ppm Pb, 3.0ppm Cd, and 250ppm Zn. UK: Pb 70 ppm, Cd 1.4 ppm, and Zn 200 ppm). Irish potatoes, on the other hand: – Pb, between 0.0741 and 1.5042ppm; Cd, between 0.008 and 0.0931ppm; and Zn, between 0.1038 and 88.0503ppm). The total metal concentrations were divided into four operationally defined fractions (exchangeable and carbonate, Fe and Mn oxides, organic matter, and residual fractions) using a modified sequential extraction process of Tessier et al., (1979). Where it was found that the majority of metals were partitioned to the residual fraction (Zn-138.85ppm, Pb-55.59ppm, and Cd-2.5ppm), suggesting that none of the metals analyzed have contaminated the soils in the field. The soils matrix was only minimally contaminated with Cd according to pollution indices when compared to Banat et al., 2005 criteria. Cd had an enrichment factor value of 15.4 and an I-geo factor of 4. The bulk partitioning of the metals onto the residual fraction suggests that the heavy metals have a lithogenic origin, meaning that they were directly inherited from the parent material. It also suggests that there is a low probability of contamination transfer under customary cultural activities. However, severe soil disturbance from mining would increase Irish potatoes’ and other plants’ ability to absorb metals, increasing the risk of biomagnifications. This would also result in significant soil pollution and water body contamination.

1.0 Chapter One Introduction

In the state of Jos plateau, tin mining began in 1902 and is now the main source of columbite production (Adegboye, 2012). The social and economic structure of the study area has undergone significant changes as a result of tin mining (Adegboye, 2012). According to Patterson (1986), the low amount of arable land in the Jos plateau region is a result of the extensive surface mining. According to (Scholar, 1979), mined soils have lower agricultural value than nearby natural land. The acha, dauro, maize, millet, and Irish potato are examples of low agricultural value, quickly growing, and low nutrient demanding crops produced on such mined ground. According to (Calvert, 1990), the indiscriminate mining on the Jos plateau exposed numerous areas to erosion and decreased the amount of arable ground suitable for cereal cultivation. The quantity of minerals lost during mining lowers the amount of nutrients that are already in the soil (Adegboye, 2012). The Jos South local government region has been heavily mined, and draglines and other large earth-moving machinery have been used frequently. Deep excavations, substantial overburden dumping, mine ponds, mine tailings, and slurry wash deposits are hence features of the zone (Olaniyan, 1998; Musa et al., 2011). Deep mining, which is the excavation of underlying sand, has produced mining pits, man-made lakes, pools, and ponds that have a significant impact on both the people and agricultural practices, according to Gyang et al. (2010). Mining ponds have historically been both a human and animal death trap (Davis, 2001).