Mercury (Hg) emissions from point sources to air may disperse over long distance depending on Hg speciation in the plume. A significant fraction of Hg, particularly in its divalent forms, deposits locally and causes pollution to surrounding biomes. The objective of this study was to investigate (1) the historic Hg deposition to the immediate vicinity of an industrial complex that had intentional use of Hg (i.e., chlor-alkali and polyvinyl chloride production) for 5 decades until 2011, and (2) the Hg⁰ re-emission from soil to air soon after the closure of the facility. The spatial distribution of near-ground Hg⁰ vapor in air, soil Hg concentration and stable isotope ratio, air-soil Hg⁰ flux and Hg⁰ concentration in soil pore-gas were measured. It was found that the surrounding soils are severely contaminated with Hg due to the Hg release of the industrial complex, displaying soil Hg content up to 4.8 μg g⁻¹. A spatial trend of Hg mass dependent isotope fractionation signature (δ²⁰²Hg = −2.11‰–0.72‰) with respect to the distance from the closed facility was identified, representing a mixing between regional background and industrial Hg sources. Hg release from the industrial operation enhanced surface soil Hg content within a 6.5-km radius from the facility. Inside the facility, residual Hg wastes (i.e., electrolysis sludge and consumed HgCl₂ catalyst) represent a strong localized emission source of atmospheric Hg⁰. Near-ground atmospheric Hg⁰ concentration and soil Hg⁰ efflux progressively elevated toward the facility with an increase by 2–3 orders of magnitude compared to the values observed in the off-site background. These results suggest that the natural soil surfaces surrounding the closed industrial facility act as a large nonpoint source emitting legacy deposited Hg as much as the release from naturally enriched mines.

从点源到空气的汞（Hg）排放可能会扩散很长一段距离，具体取决于烟羽中的Hg形态。汞的相当一部分，尤其是以其二价形式存在的汞，会局部沉积并污染周围的生物群落。这项研究的目的是调查（1）到2011年为止有意使用Hg（即氯碱和聚氯乙烯生产）的工业园区附近历史汞的沉积情况，以及（2）设施关闭后不久，Hg ⁰从土壤重新排放到空气中。空气中近地面Hg ⁰蒸气的空间分布，土壤Hg浓度和稳定同位素比，空气-土壤Hg ⁰通量和Hg ⁰测量土壤孔隙气体中的浓度。发现由于工业复合体的汞释放，周围的土壤被汞严重污染，显示土壤汞含量高达4.8μgg ^-1。汞柱质量相关的同位素分馏签名（δ的空间趋势²⁰²汞柱= -2.11‰-0.72‰）相对于从所述闭合设备的距离被确定，代表区域的背景和工业汞源之间的混合。工业生产中释放的Hg会在距工厂6.5公里半径内提高表层土壤Hg的含量。在设施内部，残留的汞废物（即电解污泥和消耗的HgCl ₂催化剂）是大气中Hg ⁰的强烈局部排放源。。与场外背景相比，近地大气中的Hg ⁰浓度和土壤Hg ⁰外排向设施的方向逐渐升高，增加了2-3个数量级。这些结果表明，封闭的工业设施周围的天然土壤表面是一个大型的非点源，其排放的残留汞与从自然富集的矿山中释放的汞一样多。