Field and modelling studies of Escherichia coli loads in tropical streams of montane agro-ecosystems
Field and modelling studies of Escherichia coli loads in tropical streams of montane agro-ecosystems
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DOI：
10.1016/j.jher.2015.03.003
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发表时间：
2015-12-01
影响因子：
2.8
通讯作者：
Ribolzi, Olivier
中科院分区：
文献类型：
--
作者：
Causse, Jean;Billen, Gilles;Ribolzi, Olivier
尽管粪便对人类健康和经济产生了重要影响，但在热带农村地区，土壤和水的粪便污染程度仍然鲜为人知。在这里，我们探讨了热带乡村地区河流在不同时空尺度上的污染源、路径和时空动态。在湄公河支流南汗河（老挝人民民主共和国北部）测量了粪便指示菌 (FIB) 大肠杆菌 (E. coli) 的浓度。 2011 年，在对比水文条件（即基流和暴风雨期间）以及雨季和旱季期间对源头到干流进行了测量。结果表明，大肠杆菌污染受到土地利用（即人类和牲畜粪便带到土壤表面的细菌储量）和水文（即地表径流对河流排放的贡献）的控制。直接点源污染在这个农村流域中并不重要，但在高排放期间，FIB 浓度经常超过 5000 MPN 100 mL(-1)。 Seneque/Riverstrahler 模型的大肠杆菌模块适应了 Nam Khan 河的背景，通过现场观察进行了验证，并用于分析未来粪便污染的情况（不断变化的人口趋势和废水管理的改进）。我们发现，FIB 污染恶化的风险更多地与预计的未来农村人口外流和废水管理实践有关，而不是与这些高地系统人口压力的增加有关。 (C) 2015 年国际水文环境工程与研究协会亚太分部。由 Elsevier B.V. 出版。保留所有权利。
The extent of faecal contamination in soils and water is still poorly known in rural tropical areas despite its important consequences on both human health and the economy. Here we explore the sources, pathways, and spatio-temporal dynamic of contamination in rivers of a rural tropical area at different spatial and temporal scales. Concentrations of Escherichia coli (E. coli), a faecal indicator bacteria (FIB), were measured in the Nam Khan river, tributary of the Mekong river (North Lao PDR). Measurements were made from the headwaters to the main stream under contrasted hydrological conditions (i.e. during base flow and stormflow) and during the wet and dry seasons in 2011. The results show that E. coli contamination is controlled by both land use (i.e. stock of bacteria brought to the soil surface by the faeces of human and livestock) and hydrology (i.e. contribution of overland flow to the river discharge). Direct point-source contamination is of minor importance in this rural watershed, however, during high discharge the concentration of FIB frequently exceeds 5000 MPN 100 mL(-1). The E. coli module of the Seneque/Riverstrahler model was adapted to the context of the Nam Khan river, validated with field observations and used to analyse future scenarios of faecal contamination (changing demographic trends and improvements in wastewater management). We found that the risk of worsening FIB contamination was more related to the predicted future rural exodus and to wastewater management practices rather than to an increase in demographic pressure in these upland systems. (C) 2015 International Association for Hydro-environment Engineering and Research, Asia Pacific Division. Published by Elsevier B.V. All rights reserved.