Baseline groundwater chemistry : the Chalk aquifer of Hampshire

Baseline groundwater chemistry : the Chalk aquifer of Hampshire
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地下水化学基线：汉普郡的白垩含水层

DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
P. Smedley
P. Smedley
中科院分区：
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文献类型：
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作者：
M. Stuart;P. Smedley

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这项研究的特点，在无机化学的空间和时间的变化， 汉普郡白垩含水层，从东北部的贝辛斯托克到卡德南 在西南部。调查的目的是评估可能的自然基线化学的 通过查明主要控制过程（自然和人为）来控制地下水 包括地球化学反应和污染物输入。结果已收集 从30个地下水源的战略抽样中，结合现有的 地下水、降雨、矿物学和地球化学数据。 汉普郡白垩形成了一个主要的背斜结构，向南倾斜 下第三纪盖层进入汉普郡盆地，向北进入伦敦盆地。它 形成了一个区域性的重要含水层，可供饮用和农业使用， 基流到河流测试和Itchen，这是广泛用于捕鱼。 结果表明，该区地下水为典型的无压白垩系地下水，Ca-HCO 3 类型.随着水停留时间的增加，自然化学发生变化， 在古近纪盖层之下从地下水分水岭向下倾斜。那里 是一个显着的影响，地下水化学从古近纪盖在南部的 研究区的Mg、K、SO 4、Br、F、Ba、Sr、Li、Rb、Se、Cr Mo、Ni、U与露头白垩地下水相比。 人类的影响在地下水中硝酸盐的分布中最为明显。这些 在区域范围内较高，一个分析的水源地下水含量高于欧共体/国家 饮用水限值为11.3 mg L-1（以氮计），时间序列数据表明， 在过去几十年中，一些地下水中的浓度。的广泛存在 硝酸盐表明含水层已经并继续受到 农业实践。其他氮物质（NO2和NH 4）和P的含量略高于 2004年12月20日至2005年12月31日期间， 研究领域，特别是Meon山谷。Cu和Zn的浓度也存在于 在某些地区，浓度相对较高（分别高达31 μg L-1和253 μg L-1）， 地下水这可能是由于井口管道系统的污染， 导致含水层内积累的过程。
This study characterises the spatial and temporal variations in inorganic chemistry in the Chalk aquifer of Hampshire, spanning the area from Basingstoke in the north-east to Cadnam in the south-west. The investigation aims to assess the likely natural baseline chemistry of the groundwater by identifying the dominant controlling processes (natural and anthropogenic) including from biogeochemical reactions and pollutant inputs. Results have been collected from strategic sampling of 30 groundwater sources, in conjunction with collation of existing groundwater, rainfall, mineralogical and geochemical data. The Hampshire Chalk forms a predominantly anticlinal structure which dips southwards beneath Palaeogene cover into the Hampshire Basin and northwards into the London Basin. It forms a regionally significant aquifer for potable and agricultural use and also provides baseflow to the Rivers Test and Itchen, which are used extensively for fishing. The results show that groundwater is typical of unconfined Chalk groundwater, of Ca-HCO3 type. Variations in the natural chemistry take place with increasing residence time as water moves away from the groundwater divide downgradient beneath the Palaeogene cover. There is a notable effect on groundwater chemistry from the Palaeogene cover in the south of the study area with slightly increased concentrations of Mg, K, SO4, Br, F, Ba, Sr, Li, Rb, Se, Cr, Mo, Ni, U compared to outcrop Chalk groundwater. Human impact is most plainly visible in the distributions of nitrate in the groundwater. These are regionally high, with one analysed source having groundwater above the EC/national drinking-water limit of 11.3 mg L–1 as N and time-series data demonstrating an increase in concentrations in some groundwaters over the last few decades. The widespread presence of nitrate indicates the extent to which the aquifer has been and continues to be influenced by farming practices. Other nitrogen species (NO2 and NH4) and P are present at slightly above concentrations that would be considered baseline in groundwater from the south-east of the study area, particularly the Meon valley. Concentrations of Cu and Zn are also present at relatively high concentrations (up to 31 μg L–1 and 253 μg L–1 respectively) in some groundwaters. This may be due to contamination from wellhead pipework rather than processes leading to accumulation within the aquifer.