Odesa G E, Okanigbuan P N, Eyankware M O, Ngozi-Chika C S, Oghenetega Efetobo
Department of Geology, Faculty of Science, Dennis Osadebay University, Asaba, Delta State, Nigeria.
Department of Geology, Faculty of Science, Dennis Osadebay University, Asaba, Delta State, Nigeria.
J Contam Hydrol. 2025 Sep;274:104665. doi: 10.1016/j.jconhyd.2025.104665. Epub 2025 Jul 4.
The study evaluated the quality of the surface water overflowing the lignite seams and groundwater in Obomkpa and its vicinity to ascertain its pollution status. Nineteen groundwater samples were collected and tested following APHA standards to assess physicochemical properties, including Cl, HCO3, SO4, Fe, Mn, Pb, Zn, Cr, Ca, Mg, and Na (mg/l). Additionally, six surface water samples were analyzed for polycyclic aromatic hydrocarbons (PAHs) alongside the physicochemical parameters. In a novel, integrated approach, the study simultaneously assessed both heavy metals and PAHs using a suite of advanced pollution and health risk indices such as Contamination Factor (CF), Pollution Index of Groundwater (PIG), Nemerow Pollution Index (NPI), Geoaccumulation Index (Igeo), and Entropy Water Quality Index (EWQI), as well as indices for PAHs such as Carcinogenic Toxic Equivalence (TEQs) and Excess Cancer Risk (ECR), were employed to determine the suitability of the water for domestic use. The results revealed a predominant Ca-Mg-HCO3 water type, with the evaluated PIG indicating that approximately 31.5 % of the groundwater samples fell within the low pollution categories. While EWQI showed that 20 % of the total samples fell within the good water quality categories, NPI indicated that 20 % of the samples were slightly polluted. The evaluated CF and Igeo revealed that the groundwater quality ranged from slightly polluted to significantly contaminated due to iron contamination. PAH content was minimal, ranging from 0 to 1 × 10-5 mg/L, which falls within the WHO (2015) acceptable limit for water consumption. An in-depth evaluation of the health hazards stemming from the cancer-causing properties of PAH-polluted water using TEQs and ECR further confirms that the water meets the standards for domestic use. Inferences from the principal component analysis suggested that the dissolution of ferruginous sandstone was the major influence on groundwater quality, highlighting the need for ongoing monitoring.
该研究评估了奥邦克帕及其附近地区褐煤层溢出的地表水和地下水的质量，以确定其污染状况。按照美国公共卫生协会（APHA）标准采集并检测了19个地下水样本，以评估其物理化学性质，包括氯（Cl）、碳酸氢根（HCO3）、硫酸根（SO4）、铁（Fe）、锰（Mn）、铅（Pb）、锌（Zn）、铬（Cr）、钙（Ca）、镁（Mg）和钠（Na）（毫克/升）。此外，对6个地表水样本进行了多环芳烃（PAHs）分析以及物理化学参数分析。该研究采用一种新颖的综合方法，使用一系列先进的污染和健康风险指数，如污染因子（CF）、地下水污染指数（PIG）、内梅罗污染指数（NPI）、地累积指数（Igeo）和熵水质指数（EWQI），同时评估重金属和多环芳烃，还采用了多环芳烃相关指数，如致癌毒性当量（TEQs）和超额癌症风险（ECR），以确定这些水是否适合家庭使用。结果显示主要为钙-镁-碳酸氢根水型，评估的PIG表明约31.5%的地下水样本属于低污染类别。EWQI显示20%的总样本属于水质良好类别，而NPI表明20%的样本受到轻度污染。评估的CF和Igeo显示，由于铁污染，地下水质量从轻度污染到严重污染不等。多环芳烃含量极低，范围为0至1×10-5毫克/升，符合世界卫生组织（2015年）的饮用水可接受限值。使用TEQs和ECR对受多环芳烃污染的水的致癌特性所产生的健康危害进行的深入评估进一步证实，这些水符合家庭使用标准。主成分分析的推断表明，铁质砂岩的溶解是影响地下水质量的主要因素，凸显了持续监测的必要性。
