Acid rain effects on aluminum mobilization clarified by inclusion of strong organic acids.
Acid rain effects on aluminum mobilization clarified by inclusion of strong organic acids.
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DOI：
10.1021/es061437v
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发表时间：
2007
影响因子：
11.4
通讯作者：
G. Lawrence;J. Sutherland;C. Boylen;S. Nierzwicki-Bauer;B. Momen;B. Baldigo;H. Simonin
中科院分区：
文献类型：
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作者：
G. Lawrence;J. Sutherland;C. Boylen;S. Nierzwicki-Bauer;B. Momen;B. Baldigo;H. Simonin
评估酸沉积对水生生态系统的影响常常受到自然产生的有机酸度并发症的阻碍。PH和ANCG是最常用的化学效应指标，它们的测量会受到有机酸存在的很大影响。PH和无机铝之间的关系也会被有机酸改变，无机铝对许多形式的水生生物群都是有毒的。然而，当无机铝浓度与ANC(钙、镁、钠和钾的总和，减去S042-、N03-和Cl-)作图时，铝动员的明显阈值变得明显。如果将强有机阴离子的浓度作为ANC的负组分包括在内，则阈值出现在ANC值大约为零的时候，这是理论上电荷平衡约束的期望值。调整后的ANC称为碱阳离子盈余。碱阳离子盈余与铝之间的阈值关系用来自纽约阿迪朗达克地区约200条河流的数据显示，这些河流在溶解有机碳浓度低和高的时期，以及来自纽约卡茨基尔地区的另一条河流。这些结果表明：(1)强有机阴离子有助于无机铝与SO42-和N03-的结合；(2)地表水中无机铝的存在是酸性沉积效应的明确标志。
Assessments of acidic deposition effects on aquatic ecosystems have often been hindered by complications from naturally occurring organic acidity. Measurements of pH and ANCG, the most commonly used indicators of chemical effects, can be substantially influenced by the presence of organic acids. Relationships between pH and inorganic Al, which is toxic to many forms of aquatic biota, are also altered by organic acids. However, when inorganic Al concentrations are plotted against ANC (the sum of Ca2+, Mg2+, Na+, and K+, minus S042-, N03-, and Cl-), a distinct threshold for Al mobilization becomes apparent. If the concentration of strong organic anions is included as a negative component of ANC, the threshold occurs at an ANC value of approximately zero, the value expected from theoretical charge balance constraints. This adjusted ANC is termed the base-cation surplus. The threshold relationship between the base-cation surplus and Al was shown with data from approximately 200 streams in the Adirondack region of New York, during periods with low and high dissolved organic carbon concentrations, and for an additional stream from the Catskill region of New York. These results indicate that (1) strong organic anions can contribute to the mobilization of inorganic Al in combination with SO42- and N03-, and (2) the presence of inorganic Al in surface waters is an unambiguous indication of acidic deposition effects.