Data_Sheet_1_Physicochemical Parameters and Alarming Coliform Count of the Potable Water of Eastern Himalayan State Sikkim: An Indication of Severe Fecal Contamination and Immediate Health Risk.PDF

Continuous decline in potable water sources has raised serious concerns over human health. Developing countries are the most affected in this regard due to a lack of proper hygiene maintenance. Sikkim, an Eastern Himalayan state with mountains as the predominant topological features, harbors several perennial natural springs. Spring water is the primary source of potable water for the population in four districts of the state viz. East, West, North and South. Recent outbreaks of water-borne diseases and the relative lack of scientific studies on its potential correlation with the water quality of the area have educed this study. Physicochemical parameters of springs, community reservoirs, and household water were analyzed by ICP-MS and multi probe meter. Using the membrane filtration method, the microbial quality of the water samples during different seasons was assessed, primarily evaluating the presence of fecal indicators viz. Escherichia coli, total coliform and Enterococcus. The seasonal risk category of the water sources was also determined. Most of the physicochemical parameters of the spring water were within the permissible limits of WHO standards. However, water from four districts was recorded with traces of toxic heavy metals like mercury (0.001–0.007 mg/l), lead (0.001–0.007 mg/l), and selenium (0.526–0.644 mg/l), which are above the permissible limits of WHO. All the spring water samples were categorized as Mg-HCO3- type and can be predicted as shallow fresh ground water based on the piper analysis. Microbial confirmatory testing indicated severe fecal contamination of water sources with high counts of total coliform (TC), Escherichia coli (EC) and Enterococcus (EN). The highest level of TC was recorded from West Sikkim (37.26 cfu/100 ml) and the lowest in North Sikkim (22.13 cfu/100 ml). The highest level of contamination of E. coli and Enterococcus was found in East Sikkim (EC = 8.7 cfu/100 ml; EN = 2.08 cfu/100 ml) followed by South Sikkim (EC = 8.4 cfu/100 ml; EN = 2.05 cfu/100 ml). There was a significant positive correlation between the contamination levels of the spring water and the community reservoir tank. As far as the seasonal variation is concerned, the rainy season showed the most contamination with coliform correlating with a high incidence of different water-borne diseases (East = 86%; West = 100%; South = 100%; North = 80%).

饮用水源的持续减少已引发人类健康层面的严重担忧。发展中国家因缺乏规范的卫生维护措施，在此问题中受影响最为严重。锡金邦作为喜马拉雅东部的行政区，以山地为主要地形特征，境内分布多处常年性天然泉眼。天然泉水是该邦东、西、北、南四个行政区居民的主要饮用水源。近期水源传播疾病的暴发，以及针对该区域水质与疾病潜在关联的科学研究相对匮乏，促使本研究得以开展。本研究采用电感耦合等离子体质谱法（ICP-MS）与多参数水质检测仪，对泉眼、社区蓄水池及家庭用水的理化参数展开分析；采用膜过滤法（membrane filtration method），对不同季节采集的水样开展微生物质量评估，重点检测粪便指示菌：大肠埃希氏菌（Escherichia coli）、总大肠菌群（total coliform）与肠球菌（Enterococcus），同时确定了各水源的季节性风险等级。绝大多数泉水的理化参数均符合世界卫生组织（WHO）标准规定的限值要求。但四个行政区的水样中均检出汞（0.001–0.007 mg/l）、铅（0.001–0.007 mg/l）与硒（0.526–0.644 mg/l）等有毒重金属，其浓度超出世界卫生组织（WHO）的限值标准。经派珀三线图分析（Piper analysis），所有泉水样均被归类为Mg-HCO3-型水，可推断为浅层淡水地下水。微生物验证检测结果显示，水源存在严重的粪便污染，总大肠菌群（TC）、大肠埃希氏菌（EC）与肠球菌（EN）的检出量均处于较高水平。总大肠菌群的最高检出量见于锡金西区（37.26 cfu/100 ml），最低检出量见于锡金北区（22.13 cfu/100 ml）。大肠埃希氏菌与肠球菌的最高污染水平均见于锡金东区（EC=8.7 cfu/100ml；EN=2.08 cfu/100ml），其次为锡金南区（EC=8.4 cfu/100ml；EN=2.05 cfu/100ml）。泉水污染程度与社区蓄水池的污染水平呈显著正相关。就季节变化而言，雨季的水源污染最为严重，总大肠菌群检出量与各类水源传播疾病的高发病率呈显著关联（东区：86%；西区：100%；南区：100%；北区：80%）。