Acid mine drainage - effect on creeks or streams in a mining community in Ghana and treatment options

Abstract

Heavy metals contamination and other physico chemical changes in underground and surface water by acid mine drainage (AMD) were determined on the impact on creeks or streams. High levels of these metals have been reported in mmmg areas over the years; however, investigations indicates that less monitoring has been done on water discharged as effluent for effective maintenance mechanisms to be effected. Field and laboratory studies were carried out within the mining community on Latitude S 2" 35 W and Longitude N 5° 31W to investigate the levels of heavy metals (As, Fe, Cu, Zn, Mn and Cd) and physico-chemical changes (pH, temperature, E.C, D.O, alkalinity, sol·, free CN) in both underground and surface water for seven sampling sites. Results from atomic absorption spectrometry (AAS) determination indicated an average concentrations of iron (6.185 mg/I) and manganese (2.271 mg/I) in both surface and underground waters which are higher than threshold limits for mmmg effluent. The physico-chemical changes were determined using standard methods. Results also indicated higher levels of electric conductivity (1435.0)1s/cm) and sulphate (344.0 mg/I). Differences in pH, temperature, E.C, alkalinity, S042-, Fe, Cu, Zn and Mn levels in the seven water samples were statistically significant (p :'S 0.05). This may be attributed to the higher release of metals, relative to H+. Result also showed significant impact of AMD on water quality in the mining area. This effect could be attributed to the release of metals as a result of oxidation of metal-bearing sulphides in the mine dumps and pits at the selected sampling sites. The study showed that addition of lime as a treatment option has not been effective. Hence new conventional methods such as Aerobic wetland, Compost or Anaerobic Wetland, Open Limestone Channels, Diversion wells, Anoxic Limestone Drains (ALD) etc. should be considered in the treatment of acidic water (AMD) in the mining area.

A Study of Environmental Assessment of Acid Mine Drainage in Ngwenya, Swaziland

“…When these ions get into solution, sulfuric acid is produced rendering the water acidic. Equations (1.1)-(1.3) below summarize the oxidation of pyrite: This acidic effluent produced during the mining process is called 'Acid Mine Drainage' (AMD) [5,6]. AMD is a major pollutant resulting in enhanced acidity of water bodies wherever it exists [7].…”

Hydrochemical Characteristics of Open-Pit Groundwater from a Closed Metalliferous Mine in O'kiep, Namaqualand Region, South Africa

“…The concentration range was determined to be 4020 to 6 020 mg/L for cations and 607 to 759 mg/L for anions with averages of 4020 and 607 mg/L, respectively. The dominance of Cl -and Na + ions in the OPGW further provided evidence of percolation into the open pit from an external saline source [37]. Other anions observed in the OPGW were F -and PO 4 3-, although at a low concentration of 5.4 to 9.6 mg/L and 3.51 to 3.77 mg/L, respectively.…”

“…Overall, water quality parameters are evaluated by comparative analyses with national guidelines [35][36][37][38][39][40][41][42][43][44]. The hydrochemical parameters of the OPGW were compared to SANS and WHO drinking water guidelines., with the OPGW having a relatively high turbidity values between 502 and 556 NTU, a significant parameter indicative of the unsuitability of the OPGW for drinking [45].…”

Environmental Assessment of Acid Mine Drainage Pollution on Surface Water Bodies around Ngwenya Mine, Swaziland

“…Filtered water samples were analysed by Ion Chromatography (IC) for seven anions, namely the halogens (F − , Br − , Cl − ), the nutrients (NO 2 -N, NO 3 -N, PO 4 -P) and 2 4SO − , the best indicator for AMD pollution [24]. The Metrohm, 861 Advanced Compact IC used was set at 17 minutes analysis time for each sample by the ASUPP4-250.…”