Spatial and temporal variation of inorganic ions in rainwater in Sichuan province from 2011 to 2016
Spatial and temporal variation of inorganic ions in rainwater in Sichuan province from 2011 to 2016
复制标题
2011-2016年四川省雨水无机离子时空变化
DOI：
10.1016/j.envpol.2019.07.109
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发表时间：
2019
影响因子：
8.9
通讯作者：
Fu Hongbo
中科院分区：
文献类型：
--
作者：
Li Junlin;Li Rui;Cui Lulu;Meng Ya;Fu Hongbo
尽管政府暗示了一系列控制空气污染的政策，但中国仍遭受严重的酸沉降。本研究采集了2011 - 2016年四川省雨水样品，测定了pH值和9种无机离子（SO 42 −、NO3−、NH 4+、Cl−、Na+、Ca 2+、K+、Mg 2+和F−）的浓度，并研究了其时空变化规律。此外，还通过统计模型揭示了降水中酸性离子的主要来源。结果显示，2011年至2016年期间，雨水持续处于高酸性，体积加权平均（VWM）pH值计算为5.18。NH 4+、Ca 2+、NO3-和SO 42-是主要的水溶性无机离子，平均占总离子的79.2%。NO3−和SO 42 −浓度的显著下降（分别从75.9 μeq L− 1降至54.3 μeq L− 1和从285 μeq L−1降至145 μeq L−1）导致雨水的pH值从2011年的5.24上升至2016年的5.70。SO 42-、NO3-、F-、Na+和K+浓度具有明显的季节变化，冬季最高，春季和秋季次之，夏季最低。冬季这些离子的高VWM浓度主要是由于不利的气象条件（例如，稀少的降雨、较低的行星边界高度和停滞的空气）和密集的人为排放。SO 42-、NO3-和F-离子在川东南地区达到峰值，是典型的工业区。NH 4+浓度从东部的268 μeq L− 1下降到西部的10.4 μeq L− 1，这可能与川东地区农业的发展有关。川东南地区由于密集的建设活动和严重的石漠化，Ca 2+达到峰值。基于正矩阵因子（PMF）分析，确定了雨水中无机离子的4个来源：人为来源、地壳来源、生物质燃烧来源和老化海盐气溶胶来源。利用地理加权回归分析了社会经济因素与雨水中离子的空间相关性。在区域尺度上，化肥消费量和农业生产总值（GAP）对NH 4+的影响由东向西逐渐增大，工业生产总值（GIP）对SO 42-和NO3-的影响也逐渐增大。
China continues to suffer from severe acid deposition, despite the government implying a series of policies to control air pollution. In this study, rainwater samples were collected from 2011 to 2016 in Sichuan province to measure the pH values and the concentrations of nine inorganic ions (SO42−, NO3−, NH4+, Cl−, Na+, Ca2+, K+, Mg2+, and F−), and then to investigate their spatiotemporal variations. Besides, the dominant sources for the acidic ions in the precipitation were also revealed by statistical model. The results showed that the rainwater continued to be highly acidic, and the Volume-Weighted Mean (VWM) pH value was calculated to be 5.18 during 2011 and 2016. NH4+, Ca2+, NO3−, and SO42−were the dominant water-soluble inorganic ions, accounting for 79.2% of the total ions on average. The remarkable decrease in NO3−and SO42−concentrations (from 75.9 to 54.3 μeq L−1and from 285 to 145 μeq L−1, respectively) resulted in an increase in the pH value of rainwater from 5.24 in 2011 to 5.70 in 2016. The concentrations of SO42−, NO3−, F−, Na+, and K+showed remarkably seasonal variation, with the highest value observed in winter, followed by spring and autumn, and the lowest value observed in summer. High VWM concentration of these ions in winter were mainly due to adverse meteorological conditions (e.g., rare rainfall, lower planetary boundary height, and stagnant air) and intensive anthropogenic emissions. SO42−, NO3−, and F−ions peaked in the southeastern Sichuan province, which is a typical industrial region. NH4+concentrations decreased from 268 μeq L−1in the east to 10.4 μeq L−1in the western Sichuan province, which could be related to the development of agriculture in the eastern Sichuan province. Ca2+peaked in southeastern Sichuan province due to intensive construction activities and severe stone desertification. On the basis of Positive Matrix Factorization (PMF) analysis, four sources of inorganic ions in rainwater were identified, including anthropogenic source, crust, biomass burning, and aging sea salt aerosol. Geographically Weighted Regression (GWR) was used to find the spatial correlations between the socio-economic factors and ions in the rainwater. At the regional scale, the influence of fertilizer consumption and Gross Agricultural Production (GAP) on NH4+increased from east to west; moreover the influence of Gross Industrial Production (GIP) on SO42−and NO3−also increased.