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首页> 外文期刊>Current Science: A Fortnightly Journal of Research >Arsenic poisoning in the Gangetic delta: An anthropogenic model
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Arsenic poisoning in the Gangetic delta: An anthropogenic model

机译：恒河三角洲的砷中毒：人为模型

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Large-scale arsenic poisoning in parts of West Bengal and in Bangladesh has been reported. Creditable work to mitigate the disaster has been taken up by delineation of the arsenic-prone aquifers and by provision of simple indigenous purification set-up for de-arsenification of drinking water in target areas. The 'end of the pipe' mitigation has brought immediate relief, but for a long-term solution and prevention of reoccurrence elsewhere, the issue must be examined at the 'beginning of the pipeline' of contamination. The situation is as follows: (a) Arsenic toxicity has surfaced only in recent times and no historical record exists concerning any previous observations. (b) The shallow wells and surface waters are not vulnerable, so are the deep aquifers. The intermediate aquifers of 50 to 80 ft depth are considered to be the principal zone of contamination. (c) Demographic survey indicates widespread contamination around the course of the Ganga and its tributaries. The situation is similar around Padma river in Bangladesh. That is, the river course is one cause of contamination. Down south, in the sea water mixing zone, chlorinity dissolves away and dilutes the element. (d) Investigations show that arsenic is associated with ferruginous coating on quartz or detrital grain surface in the aquifer zone. This means that the coating is a secondary process, precipitated from water trickling down through the aquifer. Arsenic in solution has been brought into the aquifer from outside. (e) Some geologists believe that the volcanics on Bihar Plateau (Dalma Trap, even Dhanjori Volcanics) may contribute the element, since volcanic rocks are rich in arsenic. According to them, arsenic has reached the intermediate aquifer by reworked sand dunes, so common in the Gangetic delta. However, neither has any primary arsenic mineral been reported in the ancient dunes, intermediate aquifers or the in situ volcanics, nor have any experiments been conducted to show the possibility of the element leaching out from the volcanics.
机译：据报道，西孟加拉邦部分地区和孟加拉国发生大规模砷中毒事件。划定易生砷的含水层，并通过提供简单的本地净化设施对目标地区的饮用水进行脱砷处理，开展了减轻灾害的可靠工作。 “管道末端”的缓解带来了立即的缓解，但是为了长期解决并防止其他地方再次发生，必须在污染的“管道开始”处检查该问题。情况如下：（a）砷毒性仅在最近才浮出水面，没有关于任何先前观察的历史记录。 （b）浅水井和地表水不易受影响，深水层也不易受到影响。 50至80英尺深的中间含水层被认为是主要的污染区。 （c）人口调查表明，恒河及其支流周围普遍存在污染。孟加拉国的帕德玛河周围的情况与此类似。即，河道是污染的原因之一。在南方，在海水混合区中，氯溶解并稀释了元素。 （d）调查表明，砷与含水层带中石英或碎屑颗粒表面的铁质涂层有关。这意味着涂层是次要的过程，是从滴入水的水沉淀下来的。溶液中的砷已从外部带入含水层。 （e）一些地质学家认为，比哈尔高原上的火山（达尔马陷井，甚至丹乔里火山）可能是造成这种元素的原因，因为火山岩中富含砷。据他们说，砷已经通过重造沙丘到达中间含水层，而沙丘在恒河三角洲很常见。但是，既没有在古沙丘，中间含水层或原位火山中报告过任何主要的砷矿物，也未进行任何实验来表明元素从火山中浸出的可能性。

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