Abstract

Anthropogenic activities such as artisanal gold mining have been shown to contaminate soils. When these soils are cultivated, lead (Pb)-related human health risks are expected consequent to consumption of crops produced from such soil. This study was conducted with the aim of determining the vertical distribution of Pb in Pb-contaminated farmlands around contaminated goldmine. Eight soil profile pits were dug 1 m deep and 1 m wide in eight different farmlands, two farmlands per cardinal point (North, South, East and West). Two replicates of disturbed samples were taken from each of the profile pits at incremental depths of 20 cm from soil surface up to 100 cm. Also composite samples were randomly taken at each farm where the profile pits were sunk. The vertical distribution of Pb with the highest concentration was 2025 mg kg^-1 in Farm II of Dareta North at the surface soil beside the gold ore processing site. Farms in Dareta South recorded lower values than Dareta North with values ranging from 1310 to 1586 mg kg^-1. All Pb concentration obtained in this study exceeds the international threshold value for Pb in soils (300 mg kg^-1) for both EU and USA. These results have great health implication on cropping activities which remains the main activities of households in the village. Management practices such as those that will render Pb to become unavailable or bio-accumulated is suggested while an active legal institution should be in place to check indiscriminate gold mining.

Key words: Vertical distribution, lead, artisanal mining, contaminated goldmine.