Department of Chemistry (office 8, block B), Faculty of Science, University of Ibadan, Ibadan, Nigeria.
Bull World Health Organ. 2013 Aug 1;91(8):553-561J. doi: 10.2471/BLT.12.115774. Epub 2013 May 31.
To rank pollutants in two Nigerian water supply schemes according to their effect on human health using a risk-based approach.
Hazardous pollutants in drinking-water in the study area were identified from a literature search and selected pollutants were monitored from April 2010 to December 2011 in catchments, treatment works and consumer taps. The disease burden due to each pollutant was estimated in disability-adjusted life years (DALYs) using data on the pollutant's concentration, exposure to the pollutant, the severity of its health effects and the consumer population.
The pollutants identified were microbial organisms, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead and zinc. All were detected in the catchments but only cadmium, cobalt, chromium, manganese and lead exceeded World Health Organization (WHO) guideline values after water treatment. Post-treatment contamination was observed. The estimated disease burden was greatest for chromium in both schemes, followed in decreasing order by cadmium, lead, manganese and cobalt. The total disease burden of all pollutants in the two schemes was 46 000 and 9500 DALYs per year or 0.14 and 0.088 DALYs per person per year, respectively, much higher than the WHO reference level of 1 × 10(-6) DALYs per person per year. For each metal, the disease burden exceeded the reference level and was comparable with that due to microbial contamination reported elsewhere in Africa.
The estimated disease burden of metal contamination of two Nigerian water supply systems was high. It could best be reduced by protection of water catchment and pretreatment by electrocoagulation.
采用基于风险的方法，根据对人体健康的影响对尼日利亚两个供水系统中的污染物进行排名。
通过文献检索确定研究区域饮用水中的有害污染物，并在 2010 年 4 月至 2011 年 12 月期间监测选定的污染物在集水区、处理厂和消费者龙头处的情况。利用污染物浓度、暴露于污染物、其健康影响的严重程度和消费者人群的数据，以伤残调整生命年（DALY）来估计每种污染物造成的疾病负担。
确定的污染物为微生物、镉、钴、铬、铜、铁、锰、镍、铅和锌。这些污染物在集水区均有发现，但只有镉、钴、铬、锰和铅在经过水处理后超过了世界卫生组织（WHO）的指导值。处理后发现了污染。在两个方案中，铬的疾病负担最大，其次是镉、铅、锰和钴。两个方案中所有污染物的总疾病负担分别为每年 46000 和 9500 DALY，或每人每年分别为 0.14 和 0.088 DALY，远高于 WHO 规定的每人每年 1×10(-6) DALY 的参考水平。对于每种金属，疾病负担均超过参考水平，与非洲其他地方报告的微生物污染造成的疾病负担相当。
尼日利亚两个供水系统中金属污染造成的疾病负担估计较高。通过保护集水区和电絮凝预处理可以最大程度地降低这种负担。
