Ecological risk assessment of heavy metal-contaminated soils of selected villages in Zamfara State, Nigeria

Abstract

The incidence of heavy metal contamination in Zamfara State, northern Nigeria, due to artisanal mining in some villages has resulted in the pollution of a vast area of land and water. This study evaluated the extent of environmental risks caused by heavy metals. It involved five (5) villages (Bagega, Dareta, Sunke, Tunga, and Abare) where mining activities were taking place and Anka town with no record of mining activities served as control. In each of the five villages, three sites (3) were identified as a mining site, processing site, and village making a total of sixteen (16) sites. Bulked soil samples were collected in triplicate and analyzed for iron, lead, cadmium, chromium, zinc, and nickel using flame atomic absorption spectrophotometry. Measured concentrations of the heavy metals in soils were then used to calculate the pollution and ecological risk pose by heavy metals. Their concentrations were in the order Fe > Pb > Cr > Zn > Cd > Ni, with Pb and Cd having a concentration higher than permissible levels for soils and accounted for 98.64% of the total potential ecological risk. Also, all the different pollution indices examined showed that all the sites were polluted with Cd, and all the processing sites were polluted with Pb. This reveals that processing sites pose more risk to heavy metal contamination. Correlation analysis showed a highly significant (p < 0.001) positive correlation between Pb and Zn, Cr and Ni, and a significant (p < 0.01) positive correlation between Fe and Pb, Zn and Cr. The principal component analysis suggested that Pb, Zn, Cr, and Ni likely originated from the same source, i.e., mining activities, and Fe and Cd originated from the abundant parent material in the study area.

Pollution, Ecological, and Health Risk Assessments of Heavy Metal Remediated Soil by Compost Fortified with Natural Coagulants

“…was similar to the recent study ofYahaya et al (2021) at ve villages in Zamfara state, northern Nigeria, where Cd and Pb made up 98.6% of the total potential ecological risk. High ERI was documented in agricultural soil analysed in China(Qi et al 2020).…”

Evaluation of Heavy Metals of Lead, Nickel, Cadmium, Vanadium and Some Chemical Parameters in Surface Soils of the City of Khorramabad

“…According to the results of the mentioned studies, various industries such as metal mining to computers and electronics, chemical fertilizer factories, dyeing, textile, weapons and thermal power plants, oil and petrochemical industries, steel and piping industries, hospitals and slaughterhouses livestock, and poultry are involved in causing heavy metal pollution [43,44]. Metallic elements such as copper, nickel, lead and cadmium are in the group of human activities and enter the soil through the use of chemical fertilizers, fungicides, industry, and sewage sludge [45]. In other words, human activities, especially agricultural effluents, industrial wastewaters, and pollution from the transportation industry cause a significant amount of heavy metals to enter the environment [46].…”

Environmental Effect of Mining Granite in Sauna Community of Kano State

“…Studies by Yahaya, S.M et al;(2021) indicates that The average concentrations of the heavy metals varied significantly (p < 0.001) and decreased in the following order Fe > Pb > Cr > Zn > Cd > Ni. Iron (Fe) has the highest average concentration compared with other metals studied.…”

“…These polluted soils serve as the source of dispersal of heavy metals in the environment and may enter the food chain and food web. ( Yahaya, S.M et al;(2021) . The biggest problems of the heavy metals are persistent and nondegradable, their presence in soil is stable and long-term , and these pose risks to public health and the environment.…”