Environmental Chemistry Department, Institute of Environmental Assessment and Water Research, IDÆA-CSIC, E-08034 Barcelona, Spain.
Department of Chemistry, University of Girona, C/Maria Aurèlia Capmany 69,17003 Girona, Spain.
Sci Total Environ. 2019 Jun 10;668:40-46. doi: 10.1016/j.scitotenv.2019.02.244. Epub 2019 Feb 18.
Peri-urban agriculture provides environmental benefits to the nearby urban areas. However, domestic and industrial infrastructures can be sources of pollution that can affect agricultural production. In this work, the diffusive gradient in thin film (DGT) technique was used to assess the bioavailability of mercury (Hg) in organic-amended agricultural soils, and uptake by lettuce. Two different amendments were studied individually in three different sets using a wood-based biochar at two rates (3% and 6%, w/w), and compost at one rate (30% w/w). The effect of the amendments on Hg bioavailability, mobility and uptake was investigated by means of both DGT analyses and accumulation of Hg by lettuce. DGT manufactured in-house devices with polyacrylamide gel using both open and restricted diffusive layers (ODL and RDL, respectively) were used to determine organic and inorganic Hg labile species in soils, respectively. The Hg concentration in lettuce leaves and roots were analyzed and compared with DGT measurements to predict the uptake of Hg from the different organic-amended soils and the non-amended soils. Results show that the application of biochar reduces the bioavailability of Hg in soil and, in consequence, the Hg uptake by lettuce. Inorganic Hg species were predominant in all the different sets of the experiment (62-97%), although the addition of the different amendments reduced the free ionic species in soil.
城郊农业为附近的城市地区提供了环境效益。然而，国内和工业基础设施也可能成为污染的来源，从而影响农业生产。在这项工作中，薄膜扩散梯度（DGT）技术被用于评估有机改良农业土壤中汞（Hg）的生物利用度及其对生菜的吸收。分别在三组中单独研究了两种不同的改良剂，使用两种不同的木基生物炭添加率（3%和 6%，w/w）和一种堆肥添加率（30%，w/w）。通过 DGT 分析和生菜中 Hg 的积累，研究了改良剂对 Hg 生物利用度、迁移性和吸收的影响。使用自制的带有聚丙烯酰胺凝胶的 DGT 设备，分别使用开放扩散层（ODL）和限制扩散层（RDL）来分别确定土壤中的有机和无机 Hg 活性物质。分析了生菜叶片和根系中的 Hg 浓度，并与 DGT 测量结果进行比较，以预测不同有机改良土壤和未改良土壤中 Hg 的吸收情况。结果表明，生物炭的应用降低了土壤中 Hg 的生物利用度，从而降低了生菜对 Hg 的吸收。在实验的所有不同组中，无机 Hg 物质都占主导地位（62-97%），尽管添加了不同的改良剂减少了土壤中的游离离子物质。
