Heavy Metal Analysis of Soil Around Mine Sites in Ameri, Enyigba, and Ishiagu in Ebonyi State

Heavy metal contamination of soil, water and crops, and their health impact on residents, is a persistent social issue, and several studies have identified health risks of residents living near operational and abandoned mines. In this study, eight (8) homogenous soil samples were collected from mining sites in Enyigba, Ameri and Ishiagu in Ebonyi State, south-eastern Nigeria and analyzed for Pb, Zn, Ni, Co, Mn, and Ag. Metal concentration was determined using the Atomic Absorption Spectrometry (AAS) technique. Result for the heavy metals followed the trend: Mn > Zn > Pb > Ni > Ag > Co for the soil analyzed. However, lead (Pb) was only detected in Enyigba mining sites. Metal concentrations in some samples indicated soil contamination from Mn, Pb, Zn, Ni, and Ag, which showed high concentration than the United States Environmental Protection Agency (US EPA) (1986) permissible limit for heavy metals in agricultural soil; only Co was recorded at a concentration below the US EPA (1986) permissible limit for all samples analyzed. The variations observed for the heavy metals suggest that both geologic and anthropogenic activities may be responsible for their distribution. Keywords: Anthropogenic; contamination, geologic; health risks; heavy metals; mines; soil. DOI: 10.7176/JEES/9-10-12 Publication date:October 31st 201

Speciation of Potentially Toxic Metals from the Mine Impacted soils: A Case Study of Riruwai Mining Area, Kano State, Northern Nigeria

Mining and smelting sectors contribute significantly to global growth on a regional and local scale. However, the operations are causing significant environmental damage, particularly pollution of the soil with potentially toxic metals (PTMs).  In this study, the speciation of PTMs (arsenic, cadmium, chromium, mercury, manganese, nickel, lead and zinc) from the mine impacted soils of Riruwai mining area was investigated using a modified Tessier sequential extraction method. The findings of the study revealed that all the PTMs examined are considerably associated with non-residual fractions in all the sampling locations. This indicates that all the PTMs investigated in the study area may be highly mobile in the soils and hence potentially toxic. The concentrations of PTMs in the soil’s geochemical fractions were found to vary with the sampling locations, with active mining sites significantly (p ≤ 0.05) recording the highest value, followed by farmland, while the lowest value was reported at the control site. Therefore, to protect the environment and the health of the local populace, PTMs in the soils of the study area should be regularly monitored and a treatment program should be put in place

Heavy Metals Contamination Levels in the Vegetables Grown around Riruwai Mining Area, Kano State, Nigeria

Vegetables grown in mining areas can accumulate significant amounts of heavy metals (HMs), which can cause serious developmental disorders and have long-term negative effects on public health. In the present study, the HMs contamination level in vegetables grown around the Riruwai mining area in Kano State, Nigeria, was investigated. Fifteen (15) vegetable samples were collected, including lettuce (Lacuta sativa L.), tomato (Solanum lycopersicum L.), and bean (Phaseolus vulgaris L.), as well as their corresponding soils. The levels of As, Cd, Cr, Hg, Mn, Ni, Pb, and Zn in all the samples were determined using Microwave Plasma Atomic Emission Spectrometry, and the measured concentrations were used to calculate the bioaccumulation factor (BAF). The results of the study revealed that HMs concentrations in the investigated vegetables were found to be significantly high, with the majority of levels exceeding the WHO/FAO (2007) recommended limit, and the concentration of HMs in the soil decreased in the order of Zn > Mn > Cr > Pb > As > Ni > Cd > Hg, with As, Pb, and Zn exceeding the WHO/FAO (2001) recommended limit. Pollution levels were found to significantly differ between HMs and vegetable types. BAF results revealed that cadmium is an accumulator of all the studied vegetables (BAFs > 1), while mercury was found to be an accumulator of L. sativa. Higher concentrations of these metals in vegetables and soil, particularly arsenic, cadmium, lead, and zinc, necessitate immediate scientific attention and further research to determine the optimum concentration required for human health. Planting of vegetables for human and animal consumption should be stopped until this is accomplished