贵求 英文翻译汉语 谁啊最好加我Q好多啊range 1–20 mg kg\11. There appear to be two distinct ‘triggers’ that can lead to the release of As on a large scale. Thefirst is the development of high pH (>8.5) conditions in semi-arid or

贵求 英文翻译汉语 谁啊最好加我Q好多啊range 1–20 mg kg\11. There appear to be two distinct ‘triggers’ that can lead to the release of As on a large scale. Thefirst is the development of high pH (>8.5) conditions in semi-arid or
贵求 英文翻译汉语 谁啊最好加我Q好多啊
range 1–20 mg kg\11. There appear to be two distinct ‘triggers’ that can lead to the release of As on a large scale. The
first is the development of high pH (>8.5) conditions in semi-arid or arid environments usually as a result of the
combined effects of mineral weathering and high evaporation rates. This pH change leads either to the desorption of
adsorbed As (especially As(V) species) and a range of other anion-forming elements (V, B, F, Mo, Se and U) from
mineral oxides, especially Fe oxides, or it prevents them from being adsorbed. The second trigger is the development of
strongly reducing conditions at near-neutral pH values, leading to the desorption of As from mineral oxides and to the
reductive dissolution of Fe and Mn oxides, also leading to As release. Iron (II) and As(III) are relatively abundant in
these groundwaters and SO4 concentrations are small (typically 1mg l\11 or less). Large concentrations of phosphate,
bicarbonate, silicate and possibly organic matter can enhance the desorption of As because of competition for
adsorption sites. A characteristic feature of high groundwater As areas is the large degree of spatial variability in As
concentrations in the groundwaters. This means that it may be difficult, or impossible, to predict reliably the likely
concentration of As in a particular well from the results of neighbouring wells and means that there is little alternative
but to analyse each well. Arsenic-affected aquifers are restricted to certain environments and appear to be the exception
rather than the rule. In most aquifers, the majority of wells are likely to be unaffected, even when, for example, they
contain high concentrations of dissolved Fe. # 2002 Published by Elsevier Science Ltd. All rights reserved.

贵求 英文翻译汉语 谁啊最好加我Q好多啊range 1–20 mg kg\11. There appear to be two distinct ‘triggers’ that can lead to the release of As on a large scale. Thefirst is the development of high pH (>8.5) conditions in semi-arid or
范围1-20毫克公斤1 .有似乎是两种截然不同的'诱因' ,可导致释放作为一个大的规模.那个
首先是发展高pH值（ “ > 8.5 ）条件,在半干旱地区或干旱环境,通常是由于该
综合作用的矿物风化和高蒸发率.这pH值变化导致要么脱附
作为吸附（尤其是As （ V ）的物种）和一系列其他阴离子形成的要素（五,乙,男,钼,硒和U ）由
矿产氧化物,尤其是铁的氧化物,或它可以防止他们被吸附.第二是触发的发展
强烈还原条件在近中性pH值,导致脱附从矿物氧化物和向
还原溶解铁,锰氧化物,也导致作为释放.铁（ ii ）及（三）有相对丰富,在
这些地下水和SO4的浓度是小（通常为1 mg升1或更少） .大量集中的磷酸盐,
碳酸氢盐,硅酸盐,并可能有机质可以提高解吸作为,因为竞争
吸附的网站.的一个特征高的地下水作为地区是很大程度的空间变异性,在作为
浓度的地下水.这意味着它可能有困难,或不可能的,可靠的预测可能
浓度为在某一特定以及从邻近的结果,井和手段,是有一点另类
但分析每口井.砷影响的含水层仅限于某些环境,而且似乎是例外
而非法治.在大多数含水层,多数井有可能受到影响,甚至例如,当他们
含有高浓度的溶解铁.＃ 2002年出版的由Elsevier科学有限公司保留所有权利.