| 重庆铁山坪森林土壤汞释放通量的影响因子研究 |
| 摘要点击 2269 全文点击 942 投稿时间：2013-09-16 修订日期：2013-10-31 |
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| 中文关键词 汞 自然源 土壤 释放通量 影响因子 |
| 英文关键词 mercury natural source soil emission flux impact factor |
| 作者 | 单位 | E-mail | | 王琼 | 成都信息工程学院资源环境学院,大气环境模拟与污染控制四川省高校重点实验室,成都 610225 | qiongwang1222@163.com | | 罗遥 | 清华大学环境学院,环境模拟与污染控制国家重点联合实验室,北京 100084 | | | 杜宝玉 | 清华大学环境学院,环境模拟与污染控制国家重点联合实验室,北京 100084 | | | 叶芝祥 | 成都信息工程学院资源环境学院,大气环境模拟与污染控制四川省高校重点实验室,成都 610225 | | | 段雷 | 清华大学环境学院,环境模拟与污染控制国家重点联合实验室,北京 100084 | lduan@tsinghua.edu.cn |
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| 中文摘要 |
| 对位于重庆铁山坪的马尾松林下的山地黄壤进行表层土壤（0~5 cm）的原状采集，并在实验室中进行控制实验，利用通量箱法测量原状土块表面的汞释放通量，以研究环境因子对土壤汞释放量的影响. 结果表明，土壤汞释放量与辐射强度呈显著的正相关，在相同的空气温度和土壤含水量等条件下，土壤汞释放量在光下是遮阳条件下的3~9倍. 不过，由于林下土壤常处于背阴状态，可能遮阳条件更能代表白天林下土壤汞的排放情况. 土壤汞释放量存在明显的季节变化，夏季>春秋季>冬季，空气温度与土壤汞释放呈正相关. 在低温下土壤汞释放量很低，土壤含水量影响较弱，而在高温时土壤含水量增加能明显促进土壤汞释放. 枯落物的移除会显著降低土壤汞释放通量，主要原因可能是枯落物的汞含量较高并易于还原. 土壤汞释放量在一天内也存在明显的衰减趋势，表明土壤表层的汞含量可能是森林土壤汞释放的重要限制因素. 本研究测得森林土壤汞释放通量（白天）为：夏季（14.3±19.6）ng·（m2·h）-1、春秋季（3.50±5.36）ng·（m2·h）-1、冬季（1.48±3.27）ng·（m2·h）-1，以上稳态测试结果可能高估了实际的汞排放量. |
| 英文摘要 |
| To study the effect of environmental influencing factors on soil mercury emissions, intact surface soil samples (0 to 5 cm) were collected from a Masson pine forest in Tieshanping, Chongqing to conduct controlled experiments, and soil mercury emission flux was measured by dynamic flux chambers under different conditions. The results showed that the mercury emission significantly increased with the enhancement of solar radiation, air temperature, and soil water content. The mercury emissions in sunlight were 3 to 9 times higher than those in shade, but the latter condition should be more similar to the actual condition in the field. The mercury emission flux was significantly higher in summer than in spring and autumn, and was the lowest in winter. Higher in air temperature, soil water content had a stronger effect on soil mercury emission. Removal of litterfall significantly decreased soil mercury emission, mainly because the mercury content of litterfall was higher than that in mineral soil layer. In addition, soil mercury emission had an obvious trend of decay during a day, indicating that relatively low mercury content in forest soil might be a limiting factor of mercury emission. The mercury emission flux in the daytime measured in this study was(14.3±19.6)ng·(m2·h)-1 in summer, (3.50±5.36)ng·(m2·h)-1 in spring and autumn, and (1.48±3.27)ng·(m2·h)-1 in winter. The steady-state results above might therefore be overestimation of the actual emission in the field. |
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