Urbanisation effects on groundwater chemical quality: findings focusing on the nitrate problem from 2 African cities reliant on on-site sanitation
Urbanisation effects on groundwater chemical quality: findings focusing on the nitrate problem from 2 African cities reliant on on-site sanitation
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DOI：
10.2166/wh.2007.040
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发表时间：
2007-09-01
影响因子：
2.3
通讯作者：
Pedley, Steve
中科院分区：
文献类型：
--
作者：
Cronin, Aidan A.;Hoadley, Alfred W.;Pedley, Steve
到2010年，非洲城市人口将增至4.2亿以上，就地卫生设施将是主要的排泄物处理办法。现场卫生设施的使用具有重要的公共卫生效益，但可能导致大量来自粪便的氮和氯化物进入地下水资源。硝酸盐是特别令人关注的，与潜在的N和Cl相关的浓度升高可以来自自然来源，因此重要的是要量化严重的健康问题人类活动的额外影响。一些作者使用硝酸盐和氯化物浓度之间的经验关系来评估排泄物对地下水质量的影响程度。然而，这些关系假设来自排泄物的固定负荷。氮和氯之间的关系在这里已经扩展，增加了国家的人均年氮和氯含量的估计，并从，排泄物的负荷。结果进行了比较，从两个非常不同的中型非洲城市（廷布克图，马里和利钦加，莫桑比克）的绝大多数居民使用现场卫生设施，并依赖于地下水饮用的地下水监测结果。结果说明了城市化对地下水质量的影响。它们与其他非洲城市的数据进行比较，以便计算未铺设下水道的非洲城市地区的一般硝酸盐和氯化物关系。潜在的干预措施，以帮助逮捕不断上升的硝酸盐水平，从而提供一个公共健康的好处也进行了检查。
By 2010 Africa's urban population will have grown to over 420 million with on-site sanitation the predominant excretal disposal option. The use of on-site sanitation has important public health benefits but can result in large faecally derived loadings of nitrogen and chloride to groundwater resources. Nitrate is of particular concern, with elevated concentrations linked to potentially N and Cl can derive from natural sources so it is important to quantify serious health problems the additional impact of human activities. Several authors have used empirical relationships between nitrate and chloride concentrations to assess the extent to which excretal influences groundwater quality. However, these relationships have assumed fixed loadings from excreta. Relationships between N and Cl have been extended here by adding country-specific estimates of average annual per capita nitrogen and chloride content of, and loading from, excreta. The results are compared with groundwater monitoring results from two very different mid-sized African cities (Timbuktu, Mali and Lichinga, Mozambique) where the vast majority of residents use on-site sanitation and are dependent on the subsurface water for drinking purposes. The results illustrate the impact of urbanisation on groundwater quality. They are compared with data from other African cities to allow the calculation of a general nitrate and chloride relationship for unsewered African urban areas. Potential interventions to help arrest rising nitrate levels and so provide a public health benefit are also examined.