Characterization and evaluation of the effects of mine discharges on surface water resources for irrigation: a case study of the Enyigba Mining District, Southeast Nigeria

Abstract

Mining activities generate much wastes which degenerate into various geochemical components and affect the natural composition of surface water resources. They cause Acid Mine Drainage (AMDs) and influence the hydrochemical evolution of the hydrogeological systems. This study employed hydrochemical parameters to characterize and evaluate the effects of mine discharges on irrigation surface water in the mining district of Enyigba, SE Nigeria. Twenty-four water samples were collected from surface water sources used for subsistence irrigation farming and analyzed for pH, total dissolved solids (TDS), electrical conductivity (EC), sodium (Na+), potassium (K), calcium (Ca2+), magnesium (Mg2+), bicarbonate (HCO3−), chloride (Cl−) and sulfate (SO42−), while various irrigation parameters including Soluble Sodium Percentage (SSP), Magnesium Adsorption Ratio (MAR), Sodium Percentage (Na %), Sodium Adsorption Ratio (SAR), Permeability Index (PI), Total Hardness (TH), Kelly Ratio (KR) and Electrical Conductivity (EC) were deduced. Result indicates hydrogeochemical trend of Cl− > Mg2+ > Ca2+ > SO42− > HCO3− + CO3 > Na+ + K+, while hydrogeochemical facies from Piper Trilinear plot, Durov and Schoeller plots shows that the dominant ionic species are the Mg2+, Cl−, and SO42−. Irrigation parameters such as SSP, MAR, Na %, SAR, PI, KR and EC indicate that majority of water sample are very good to moderately suitable for irrigation. Five samples around Amorie and Ameka are within the hard category for TH, which could be attributed to the high concentration of dissolved magnesium and calcium ion in the area. Apart from mine discharges, rock water interaction also affects the composition of surface water resources of the area.

A Comparative Study of Groundwater between Geological Groups of Southern Benue Trough, Nigeria Using Modelling Approach

“…For a better understanding of the exchange of ions Ca 2+ / (HCO 3 ¯ + SO 4 2 ¯) was plotted against Na + /Cl¯. Figures 7a and 7b showed that sampling points were categorized under natural state, results from Figure 7a and 7b revealed that natural salt dissolution such as carbonates rock, and silicate is the main processes controlling groundwater chemistry within the study area, this is in line with previous studies by [2] . [1] pointed out that TDS and TH are two major important parameters reflecting the quality of groundwater In this study.…”

“…Results obtained from the model revealed that groundwater collected from ARG and EAG fell within high Ca + Mg + SO 4 + Cl hydrogeochemical facies as shown in Figure 6a and 6b. The previous study within the study area revealed that groundwater was classified as moderately hard [2] , the presence of Ca and Mg ions, is the primary cause of hardness in groundwater within the study area. On general note water with high Ca+Mg is said to be hard.…”

“…of Nigeria have assessment water resources for various uses ranging from irrigation, industrial and domestic use [2][3][4] . Their findings suggested that groundwater quality and geochemistry are altered by geogenic and anthropogenic activities such as rock-water interaction, weathering, and mining, among others.…”

“…On the same note [6][7][8] acknowledge that hydrochemistry of groundwater resources depends on the following; the quality of recharge water, level of chemical weathering of diverse rock types, local or regional of an area, and lastly, human activities. According to [2][3][4][5] , awareness of hydrogeochemistry is of paramount importance as it plays a major in determining the origin, chemical composition, and characterization of groundwater concerning a particular region or locality. The importance of hydrogeochemistry cannot be underestimated as it has led to several detailed studies on groundwater quality deterioration and geochemical evolution of groundwater in many parts of the globe [9][10][11] .…”

“…Two mines exist within the study area; these are the lead-zinc mine at Enyigba and Ameka. The leakage of chemicals from these mines sites, geogenic and anthropogenic activities have influenced the chemical composition of groundwater within the area [2,14] . Hence, a detailed study is necessary to get a piece of baseline information that will in˗turn be needed to establish long˗term groundwater monitoring programs for sustainable development of groundwater within the study area.…”