Characterization of water quality index of well-water at areas of historic artisanal refining activities

Abstract

This study assessed the quality of water in the area and possible sources of water contaminants using some physicochemical properties of groundwater from hand-dug wells impacted by artisanal refining activities in some settlements in Ahoada West and Ahoada East Local Government Areas of Rivers State. Three sampling sites and a control site (Igbu Ulagbe - Idu-Ekpeye, Igbu Odiabidhi -Opkorowo, Igbu Okpudhor - Ubeta) were studied. Oil spills resulting from the artisanal crude oil refining activities have led to the contamination of groundwater in Ahoada-East and Ahoada-West Local Government Areas. Results of the physiochemical analysis showed that values of turbidity, pH, Temperature, total hydrocarbon content and dissolved oxygen at three sites; Igbu Ulagbe -Idu Ekpeye (20.95±0.82 NTU, 5.00±0.15, 29.3±0.71oC, 24.72±2.80mg/l & 4.10±0.47mg/l), Igbu Odiabidhi- Okporowo (27.40±0.59 NTU,5.24±0.27, 27.6±0.34oC, 25.15±1.02mg/l & 4.59±0.78mg/l ), and Igbu Okpudhor - Ubeta (30.53±1.38 NTU, 4.29±0.09, 29.5±0.29oC, 23.88±0.54mg/l & 4.47±0.64mg/l) were above NSDWQ standard. Values of THC at Igbu Ulagbe Idu Ekpeye (24.72 mg/l), Igbu Odiabidhi -Okporowo (25.15mg/l) and Igbu Okpudhor -Ubeta (23.88 mg/l) were above NSDWQ, (2007) standard (0.3mg/l). Values of cadmium, chromium and lead were above NSDWQ, (2007) standards. The result of the total heterotrophic bacteria count (THBC) was above the maximum contamination Levels (MCLs) of 500cfu/100ml in drinking water. The result obtained at the control station (Igbu Ogbor -Ahoada) is relatively within the permissible limit except for nutrients, THBC, temperature and turbidity. The quality of water is anchored on the result of the groundwater physico-chemical characteristics through which the water quality can be determined with ease. The result of the analysis of the studied parameters was applied to compute the WQI of well water from the area. The WQI of the three stations and control were found to be 194.71, 258.30, 293.30 and 52.91 respectively indicating that the water in the respective stations was of unsuitable water quality- UWQ (category 5 for the study area and category 3 for the control station-PWQ) thus suggesting that the well water sample studied is unsafe for consumption. The study therefore suggested that measures of controlling the heinous act be activated as quickly as possible by the government and IOCs operating in the area to mitigate the toxicological health hazards on the ecosystem and residents of the area who relied on the well water for consumption and other domestic purposes.