A catchment-scale method to simulating the impact of historical nitrate loading from agricultural land on the nitrate-concentration trends in the sandstone aquifers in the Eden Valley, UK.
A catchment-scale method to simulating the impact of historical nitrate loading from agricultural land on the nitrate-concentration trends in the sandstone aquifers in the Eden Valley, UK.
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DOI：
10.1016/j.scitotenv.2016.10.235
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发表时间：
2017-02
期刊：
影响因子：
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通讯作者：
Lei Wang;S. Burke
中科院分区：
文献类型：
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作者：
Lei Wang;S. Burke
主要由农业活动造成的硝酸盐水污染仍然是一个世界性的问题。由于地下水系统中硝酸盐的时滞性，它会导致严重的长期环境和人类健康问题。然而，在环境水管理中很少考虑到地下水中硝酸盐的遗留问题。我们开发了一种简单的集水规模的方法来调查历史上从农田装载的硝酸盐对砂岩中硝酸盐浓度趋势的影响，砂岩代表了英国伊甸园山谷的主要含水层。该模型考虑了含水层中硝酸盐的时空分布、低渗透浅层沉积、双孔非饱和带和硝酸盐稀释等因素。用蒙特卡罗模拟方法分析了参数敏感性，并利用观测数据对模型进行了校准。生成了研究区4个含水层带1925-2150年平均硝酸盐浓度的时间序列。结果表明，‘St Bees砂岩’、‘硅化Penrith砂岩’和‘非硅化Penrith砂岩’的硝酸盐浓度在下降到稳定水平之前一直在上升或保持在较高水平，而在‘Brockram Penrith砂岩’中的硝酸盐浓度在略有下降后将趋于平稳。这项研究可以帮助政策制定者更好地了解当地的硝酸盐遗产问题。它还提供了一个框架，用于通报为实现水质达标而采用的不同情景的长期影响和时间表。这种模型需要相对温和的参数，并且很容易移植到其他领域。
Nitrate water pollution, which is mainly caused by agricultural activities, remains an international problem. It can cause serious long-term environmental and human health issues due to nitrate time-lag in the groundwater system. However, the nitrate subsurface legacy issue has rarely been considered in environmental water management. We have developed a simple catchment-scale approach to investigate the impact of historical nitrate loading from agricultural land on the nitrate-concentration trends in sandstones, which represent major aquifers in the Eden Valley, UK. The model developed considers the spatio-temporal nitrate loading, low permeability superficial deposits, dual-porosity unsaturated zones, and nitrate dilution in aquifers. Monte Carlo simulations were undertaken to analyse parameter sensitivity and calibrate the model using observed datasets. Time series of annual average nitrate concentrations from 1925 to 2150 were generated for four aquifer zones in the study area. The results show that the nitrate concentrations in ‘St Bees Sandstones’, ‘silicified Penrith Sandstones’, and ‘non-silicified Penrith Sandstones’ keep rising or stay high before declining to stable levels, whilst that in ‘interbedded Brockram Penrith Sandstones’ will level off after a slight decrease. This study can help policymakers better understand local nitrate-legacy issues. It also provides a framework for informing the long-term impact and timescale of different scenarios introduced to deliver water-quality compliance. This model requires relatively modest parameterisation and is readily transferable to other areas.