福建省德化县金矿区民间冶炼活动相关的土壤与大气汞污染特征

Artisanal Gold Mining Related Mercury Pollution in Soils and Atmosphere in Mountains in Dehua County,Fujian Province

民间小规模金矿混汞冶炼活动因缺乏环保措施常常造成周围环境严重的汞污染,目前已被认定为全球最大的人为汞污染排放源。福建省德化县山区土壤汞含量异常升高和该地区民间小规模金矿冶炼活动密切相关,对当地土壤总汞、大气总汞污染分布及土壤表面汞释放的调查研究表明:金矿区周边村子稻田土壤汞平均质量分数达(5.180±7.191)mg/kg,距金矿最近民间冶炼活动最集中的邱村稻田总汞质量分数平均值达到(15.658±12.726)mg/kg,随着距离金矿点越远民间冶炼活动减少,土壤总汞含量呈下降趋势。区域大气总汞平均质量浓度为(36.4±24.3)ng/m^3,邱村大气总汞质量浓度平均值(77.2±42.4)ng/m^3;工作区4个土-气界面汞通量均值分别为:华口(109.6±55.9)ng/(m^2h),邱村(97.1±36.1)ng/(m^2h),大安(63.5±12.6)ng/(m^2h),中仙(25.9±23.5ng/(m^2h)。因地形复杂,微气象条件差异及土地利用差异等综合因素制约,土壤汞含量与大气总汞含量、释放通量间没有显著相关关系,华口测点土壤释汞通量最大。工作区民间金矿冶炼活动历史造成当地环境的汞污染及其环境影响将长期存在。

Artisanal and small-scale gold mining （ASGM） poses serious mercury contamination to surrounding ecosystems. At present ASGM is the largest source of global Hg emissions. Elevated mercury of soils found through eco-geochemistry survey in mountain areas in middle Fujian Province , has close relationship with former artisanal gold mining activities. Investigations on the distribution of mercury in soils, atmosphere and fluxes from soil to atmosphere yield the following results. The mean value of total Hg concentration in paddy soils around villages is （5. 180±7. 191）mg/kg,the highest mean value of total Hg concentration in paddy soils, （15. 658±12. 726）mg/kg in Qiucun, and the mean value of total Hg in paddy soils decreases with the distances between villages with the gold mine sites increased. The average mercury concentration in the atmosphere is （36.4±24.3）ng/ma , and the mean value of Qiucun＇s （77.2±42.4）ng/ ma ; the mercury fluxes to the atmosphere from four sites are Qiucun（97. 1±36.1）ng/（m^2h）,Da＇an（63.5 ±12.6）ng/（m^2h）,Huakou（109.6±55.9）ng/（m^2h）,Zhongxian（25.9±23.5）ng/（m^2h）. There is no significant relationship between soil Hg with the total Hg in ambient air and mercury fluxes ,due to solar ra- diation,temperature of the micro-climate feature and complex topography conditions. The mercury pollution from the historical ASGM to the local environment will long exist in the area.