作 者 ：周光益,田大伦,杨乐苏,邱治军,王旭,谭斌
期 刊 ：生态学报 2009年 29卷 9期 页码：4924~4933
Keywords:Liuxihe, acid rain, chemical composition, ocean source,
摘 要 ：通过2006年6月~2008年5月在广州流溪河地区采集的106次降雨水样（雨量范围0.7～268.6 mm）及其化学测试，论述了几类主要离子在降水中的含量特征、季节变化、物质的海洋来源以及雨水中离子平衡等。结果显示：(1)流溪河周边没有明显的点污染源，但酸雨降水量占总降水量的69.5%，说明降水中的污染物来自该地南部和北部污染区的中距离传输；如夏季和秋季时，台风等海洋气流把珠三角南部更多的NOx传输至该地，使得雨水中NO-3含量在夏季和秋季最大。(2)降水中的年平均F-、Cl-、NO-2、NO-3、PO3-4、SO2-4、NH+4、Ca2+、Mg2+、K+、Na+和Al3+离子浓度分别为3.76、22.80、0.45、25.22、0.86、629、41.5、35.77、2.93、5.45、14.8和0.943 μeq?L-1；且单个降水事件中的离子浓度大小与降水量呈负相关。(3)流溪河雨水酸度主要来自SO2-4、NO-3和Cl-1，且主要靠中和因子较大的NH+4、Ca2+、K+等阳离子起缓冲作用；该地降水沉降中的强酸酸量为2053 keq hm-2 a-1，NH+4、Ca2+、K+、Mg2+、Al3+的缓冲量分别为0.865、0.745、0.114、0.061、0.020 keq hm-2 a-1。(4)降水化学的月和季节波动明显，酸雨主要集中于雨季，而旱季雨水酸度较低，这和重庆及北京的情况相反。(5)在雨水中化学成分Na+全部来源海洋的假设前提下，分析得出：绝大部分Mg2+和部分Cl－(80.07%)、SO2-4(2.91%)、Ca2+(1.86%)、K+(6.19%)来自于海洋，而F-、NO-3来自海洋的贡献率非常小，可以忽略不计。
Abstract:By the monitoring and chemical analysis of wet deposition at Liuxihe, Guangzhou, 106 rainwater samples with rainfall depth from 0.7 mm to 268.6 mm were collected and tested during the studying period from June of 2006 to May of 2008. The concentration of some major ions in the precipitation, their seasonal variation, material marine sources and ion balance were studied and discussed in this paper. The main conclusions and understandings were expatiated as followings: (1) There were no obvious point pollutant sources in Liuxihe region and its surrounding area, but acidic precipitation accounts for 69.5% of its total, so it was suggested that acid rain is still a serious problem in this region and the pollutants in rainwater mainly comes from the middle\|distance transmission from the northern and southern polluting areas. For example, the largest NO-3concentration of rainwater in summer and autumn may be a result of more transport of NOx by typhoon and other ocean currents from southern polluting areas of the Pear River Delta to the this region. (2) The annual averaged ion concentration of F-, Cl-, NO-2, NO-3, PO3-4, SO2-4, NH+4, Ca2+, Mg2+, K+, Na+ and Al3+ in rainwater in this region was 3.76, 22.80, 0.45, 25.22, 0.86, 62.9, 41.5, 35.77, 2.93, 5.45, 14.8 and 0.943 μeqL-1 respectively. And there was a relation of power function between rainfall depth and ion concentration in single rainfall events, i.e. the ion concentration increased with decreasing rainfall depth. (3) The acidity of rainwater in Liuxihe was mainly caused by SO2-4, NO-3 and Cl-1, and the acidity is mainly neutralized by the main cations (NH+4, Ca2+, K+, and so on) with higher neutralization factor; The amount of strong acid entering rainwater in the site is 2.053 keq hm-2 a-1, the amount neutralized by the cation of NH+4, Ca2+, K+, Mg2+, Al3+ was 0.865, 0.745, 0.114, 0.061, 0.020 keq hm-2 a-1 respectively. (4) There was a significant monthly and seasonal fluctuation for the ion concentration; the acidic rain mainly appeared in rainy season; while the acidity of rainwater was low in dry season. Such a variation pattern was contrary to those in Beijing and Chongqing. (5) Supposing all Na in rainwater comes from ocean source, the calculation of marine contribution to the component of precipitation indicated that the vast majority of Mg2+ and part of Cl－(80.07%), SO2-4(2.91%), Ca2+(1.86%), K+(6.19%) were from ocean sources, and the ocean sources of F-, NO-3 was very low and can be ignored.
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