Assessment of human health risk concerning edible plants contamination with toxic elements around functional and derelict mines.

Edible plants samples were analysed for non-carcinogenic and carcinogenic human health risks. The elements nickel (Ni), cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr) and mercury (Hg) analysed using atomic absorption spectrophotometer (AAS). The recovery, limit of detection (LOD) and limit of quantification (LOQ) ranged from 75 to 89 %, 0.001-0.003 and 0.003-0.01, respectively. The mean value of Hg (0.34 mg/kg) exceeded the limit of 0.05 mg/kg recommended by World Health Organization (WHO). The estimated daily intake (EDI) of Cd in adults ranged from 7.93 × 10-7 to 1.43 × 10-4 and that of Hg from 0.07 to 1.27 and Cd (0.08 × 10-4) in children. These are below the oral reference doses (RfD). Hazard Quotient (HQ) of Hg in children was 1.92. The elements Hg and As obtained the highest total hazard (THI) index of 2.02 in mango1 and oil palm. Arsenic possessed the highest cancer risk of 4.5 × 10-4 in children and 1.9 × 10-4 in adults. Cancer risk (CR) ranged from low to moderate (10-6-10-4), which is below the limit of 10-3. The total carcinogenic risk (TCR) of the edible plants were above the limit of 10-6. The study identified minimal As and Hg pollution and carcinogenic risks in edible plants.

Geochemical modeling and hydrochemical analysis for water quality determination around mine drainage areas.

Water sources in mining areas do not retain their natural quality due to the influence of mine drainage. Water quality test was through hydrochemical analysis, speciation modeling, and saturation indices. Water samples were analyzed for pH, conductivity, nitrate, phosphate, sulfate, chlorite, sodium, magnesium, calcium, turbidity, total hardness, lead, zinc, iron, copper, cadmium, manganese, nickel, and chromium. Mean values of turbidity (0.13 mg/L), lead (0.01 mg/L), and cadmium (6.40 mg/L) exceeded their permissible values for potable water. Multivariate statistical analysis shows geogenic and anthropogenic sources of chemical species. Chemical speciation shows that the cations exist mostly in their soluble and mobile forms as free ions. Water quality index of 35-45.5 shows good water for drinking, irrigation, and industrial uses. The values of 63.8-68.8 and 103-121 reflect suitable water for industrial and irrigation uses. The research is integrated and credible in predicting groundwater pollutants to solve water pollution problems. PRACTITIONER POINTS: The mean value of turbidity, Pb, and Cd exceeded the WHO/NSDWQ standards for potable water. Correlation and principal component analyses show that the chemical species are from both geogenic and anthropogenic sources. Chemical speciation shows that the cations exist in their soluble and mobile forms as free ions except Cr. Saturation indices show that the minerals anhydrite, anglesite, vivianite, langite, larnakite, melanterite, and mirabilite are undersaturated in the water sources. Water quality index shows that the water is more suitable for irrigation than drinking and industrial uses.