Department of Marine Chemistry and Environmental Protection, Gdynia, Poland.
Department of Marine Chemistry and Environmental Protection, Gdynia, Poland.
Ecotoxicol Environ Saf. 2019 Oct 30;182:109434. doi: 10.1016/j.ecoenv.2019.109434. Epub 2019 Jul 13.
Rivers represent the main source of mercury (Hg) in the Southern Baltic. Nevertheless, the concentration and proportion of individual Hg forms in rivers depend on the management of the river basin, as well as on the intensity of meteorological phenomena. Hence the aim of the present study was to determine the influence of drought and rains/intense rains on the content of labile and stable Hg forms in the soil of river catchments with various types of land management, and on the inflow of bioavailable mercury to the coastal zone of the sea. Soil and sediment samples were taken from two rivers flowing into Puck Bay (Southern Baltic): the Reda and Gizdepka. In order to determine Hg concentration and the proportions of its particular forms in the collected material, the thermo-desorption method was used. Five periods were identified during which the soil was enriched with various Hg forms. The obtained results showed that in periods of intensive development of vegetation, the soil becomes enriched with absorbed mercury (Hg). On the other hand, as a result of Hg emissions during the heating of buildings, mercury associated with halides (Hg) is deposited on land, as was primarily recorded in catchments where individual household furnaces were found. Both mild and intense rainfalls intensified the surface run-off, which contributed to soil erosion, causing the transport of both Hg and Hg to the river bed. However, the soil was more enriched with labile mercury in anthropogenic catchments, as they are only slightly overgrown with vegetation, the presence of which limits soil erosion. During periods of snow melting, there was intensive leaching and transportation of Hg, which had been deposited on the land surface during the intensive combustion of fossil fuels. In each of the designated periods, stable mercury sulphide was formed in the soil. However, the highest proportion of HgS was found during a period of drought, when organic matter decomposed and there was inflow of sulphur compounds from farms. Taking into consideration the anomalous study periods, the largest load of mercury introduced along with the bed sediment of the Gizdepka into the sea was recorded during downpour/flood. Nevertheless, the most bioavailable Hg-enriched load was introduced during snow melting period.
河流是波罗的海南部汞（Hg）的主要来源。然而，河流中单个 Hg 形态的浓度和比例取决于流域管理以及气象现象的强度。因此，本研究的目的是确定干旱和降雨/强降雨对不同土地管理类型的河流流域土壤中活性和稳定 Hg 形态含量的影响，以及生物可利用汞向海域沿海地区的流入。从流入波的尼亚湾（波罗的海南部）的两条河流（雷达河和吉泽普卡河）中采集了土壤和沉积物样本。为了确定所采集材料中 Hg 浓度及其特定形态的比例，使用了热解吸法。确定了五个时期，在此期间，土壤中富集了各种 Hg 形态。研究结果表明，在植被密集生长的时期，土壤中会富集吸收态汞（Hg）。另一方面，由于建筑物加热时 Hg 的排放，与卤化物结合的汞（Hg）沉积在陆地上，这主要记录在发现个别家庭取暖炉的流域中。无论是温和的还是强烈的降雨都会加剧地表径流，导致 Hg 和 Hg 向河床的侵蚀和运输。然而，在人为流域中，土壤中更容易富集活性汞，因为这些流域只有少量植被覆盖，而植被的存在会限制土壤侵蚀。在融雪期间，Hg 会发生强烈的淋溶和运输，这些 Hg 是在化石燃料的强烈燃烧期间沉积在地表的。在指定的每个时期，土壤中都会形成稳定的硫化汞。然而，在干旱时期，当有机物质分解且农场中有硫化合物流入时，HgS 的比例最高。考虑到异常研究时期，吉泽普卡河床沉积物携带的最大汞负荷是在暴雨/洪水期间记录的。然而，在融雪期，引入的 Hg 负荷最具生物有效性。
