The effects of land use change on mercury distribution in soils of Alta Floresta, Southern Amazon
The effects of land use change on mercury distribution in soils of Alta Floresta, Southern Amazon
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DOI：
10.1016/j.envpol.2003.10.013
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发表时间：
2004-05-01
影响因子：
8.9
通讯作者：
Ribeiro, MG
中科院分区：
文献类型：
--
作者：
Lacerda, LD;de Souza, M;Ribeiro, MG
研究了1980~1996年亚马逊南部重要金矿产地阿尔塔弗洛雷斯塔表层森林和牧场土壤中汞的空间分布、污染程度和贮存量。在此期间，黄金的年均产量约为6.5吨，估计每年向环境排放的汞约为8.8吨，其中60%-80%排放到大气中。该地区的汞来源是阿尔塔弗洛雷斯塔(Alta Floresta)的矿场和黄金经销商商店，黄金在那里冶炼和商业化。森林土壤中汞的含量(15-248 ng g(-1)，平均=61.9 ng g(-1))是草地土壤(10-74 ng g(-1)，平均=33.8 ng g(-1))的1.5-3.0倍，这表明森林砍伐后土壤汞的再动员能力很强。两种土壤中汞的最高浓度都出现在距矿场20-30公里的范围内。然而，阿尔塔弗洛雷斯塔市内炼油作业的影响不那么明显。只有在距离金店所在的市中心5公里范围内才能观察到浓度稍高的情况。风向控制着汞的空间分布。背景浓度(15-50 ng g(-1))一般出现在采样网格的外周，距污染源约40公里。这表明，从采矿和精炼活动中释放出来的汞经历了快速沉积。森林土壤和牧草土壤头10 cm土壤汞累积负荷量分别为8.3mgm(-2)和4.9mgm(-2)，与黑土和水成土相当，但低于其他亚马逊地区的黄红色和黄色砖红壤和豆荚土。我们的结果表明，亚马逊地区土地利用的变化对大气中沉积在土壤上的汞有很强的再动员作用。(C)2003爱思唯尔有限公司。保留所有权利。
This study presents the spatial distribution, degree of contamination and storage capacity of Hg in surface forest and pasture soils from Alta Floresta, Southern Amazon, a significant gold mining site from 1980 to 1996. During that period, average annual gold production was about 6.5 tons, with an estimated Hg annual emission to the environment of about 8.8 tons, 60-80% of it being emitted to the atmosphere. Mercury sources to the region are mining sites and gold-dealer shops at the city of Alta Floresta, where gold is smelted and commercialized. Mercury concentrations in forest soils (15-248 ng g(-1), average = 61.9 ng g(-1)) were 1.5-3.0 times higher than in pasture soils (10-74 ng g(-1), average = 33.8 ng g(-1)), suggesting strong re-mobilization after deforestation. Highest Hg concentrations were found within a distance of 20-30 km from mining sites in both soil types. The influence of the refining operations within the city of Alta Floresta, however, was less clear. Somewhat higher concentrations were observed only within a 5 km radius from the city center where gold-dealer shops are located. Wind direction controls the spatial distribution of Hg. Background concentrations (15-50 ng g(-1)) were generally found at the outer perimeter of the sampling grid, about 40 km from sources. This suggests that Hg released from mining and refining activities undergoes rapid deposition. Estimated cumulative Hg burdens for the first 10 cm of soil averaged 8.3 mg m(-2) and 4.9 mg m(-2), for forest and pasture soils respectively and compare well with ultisols and hydromorphic oxisols, but were lower than those found in yellow-red and yellow latosols and podsols from other Amazonian areas. Our results show that changing land use in the Amazon is a strong re-mobilizing agent of Hg deposited on soils from the atmosphere. (C) 2003 Elsevier Ltd. All rights reserved.