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为了研究大气汞浓度较高地区的森林土壤的汞排放特征,选取重庆铁山坪马尾松林为研究对象,应用动态通量箱与汞分析仪联用的方法,于2012年9月~2013年7月间对土壤-大气汞交换通量进行了4个季度的现场观测,并考察了辐射强度、空气温度、空气湿度、土壤温度和土壤湿度等环境因子与大气汞浓度对汞交换通量的影响.结果表明,土壤-大气汞交换通量存在明显的季节差异,夏季汞排放量为35.3 ng·(m2·d)-1,而其他季节很小,甚至在冬春两季土壤转为大气的汞汇.汞交换通量除了受辐射强度和大气/土壤温度的影响较大之外,还与大气汞浓度呈线性负相关,白天的平衡点为5.61 ng·m-3.重庆铁山坪马尾松林土壤的汞排放量为2.65μg·(m2·a)-1,较高的大气汞浓度是该值远低于较清洁地区同类森林的重要原因.
In order to study the characteristics of mercury emission from forest soils with high concentrations of mercury in the atmosphere, the masson pine forests in Tieshanping, Chongqing were selected as research objects. The dynamic flux tank and mercury analyzer were used in the study. During the month, four quarterly field observations of soil-atmospheric mercury exchange fluxes were conducted, and the effects of environmental factors such as radiation intensity, air temperature, air humidity, soil temperature and soil moisture, and atmospheric mercury concentrations on the mercury exchange fluxes The results showed that there was a significant seasonal difference in soil-atmospheric mercury exchange flux, with mercury emissions of 35.3 ng · (m2 · d) -1 in summer and small in other seasons, even when the soil was changed to atmosphere in winter and spring Mercury exchange. Except for the strong influence of radiation intensity and atmosphere / soil temperature, the flux of mercury exchange has a negative linear correlation with atmospheric mercury concentration, with the balance point of 5.61 ng · m-3 during the day. Mercury emissions from pine forests are 2.65 μg · (m2 · a) -1. Higher atmospheric mercury concentrations are important reasons for this value being much lower than that in the cleaner forests.