Mercury fate of sewage irrigation in farmlands deserves attention with increasing scarcity of freshwater resources for agriculture in the worldwide. Soil-air total gaseous mercury (TGM) fluxes from four-sewage and one-fresh water irrigated farmlands were determined simultaneously. During maize-wheat rotation, soil-air TGM fluxes showed patterns of both emission and deposition during different growth stages. It enhanced one-order of magnitude emission with increased Hg contamination from historical sewage irrigation. A linear response relationship of TGM fluxes with soil Hg concentration was found, which showed greater TGM emission potential comparing with those from forest and urban soils. However, the ratio of soil-air TGM flux in daytime to nighttime were 3.94 in maize-season and 3.41 in wheat-season, respectively, which were little related to the change in soil Hg concentration. Furthermore, soil temperature and moisture, ambient-air TGM concentration all effected TGM evasion from sewage-irrigated soils. The data presented here suggest that evasion of TGM from historical sewage irrigation farmlands with high Hg concentrations may be potential hotspots for Hg emission in atmosphere, and it was likely to underestimate Hg emissions from farmlands in existing emissions inventory. Additional regional-investigations and process-level researches are needed to better understand role of sewage irrigation farmlands in local-global Hg-biogeochemical-cycles.

随着世界范围内农业淡水资源的日益短缺，农田污水灌溉的汞命运值得关注。同时测定了四污水和一淡水灌溉农田的土壤空气总气态汞通量。在玉米-小麦轮作期间，土壤-空气中的TGM通量在不同的生育阶段表现出排放和沉积的模式。历史污水灌溉增加了汞污染，使排放量提高了一个数量级。发现TGM通量与土壤汞浓度之间存在线性关系，与森林和城市土壤相比，TGM释放潜力更大。然而，在白天和夜间，土壤空气中TGM通量的比例在玉米季节为3.94，小麦季节为3.41，与土壤汞浓度的变化几乎没有关系。此外，土壤温度和湿度，环境空气中TGM的浓度都对污水灌溉土壤中TGM的逃逸产生了影响。这里提供的数据表明，从历史悠久的高汞浓度的污水灌溉农田逃避三聚氰胺可能是大气中汞排放的潜在热点，并且有可能低估了现有排放清单中农田的汞排放。为了更好地了解污水灌溉农田在全球局部汞生物地球化学循环中的作用，还需要进行其他区域调查和过程级研究。这里提供的数据表明，从历史悠久的高汞浓度的污水灌溉农田逃避三聚氰胺可能是大气中汞排放的潜在热点，并且有可能低估了现有排放清单中农田的汞排放。为了更好地了解污水灌溉农田在全球局部汞生物地球化学循环中的作用，还需要进行其他区域研究和过程水平研究。这里提供的数据表明，从历史悠久的高汞浓度的污水灌溉农田逃避三聚氰胺可能是大气中汞排放的潜在热点，并且有可能低估了现有排放清单中农田的汞排放。为了更好地了解污水灌溉农田在全球局部汞生物地球化学循环中的作用，还需要进行其他区域研究和过程水平研究。