Armienta María Aurora, Beltrán Margarita, Martínez Sarayth, Labastida Israel
Instituto de Geofísica, Universidad Nacional Autónoma de México (UNAM), 04510, Mexico City, Mexico.
Departamento de Energía, Universidad Autónoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo 180, 02200, Mexico City, Mexico.
Environ Geochem Health. 2020 Aug;42(8):2361-2375. doi: 10.1007/s10653-019-00424-1. Epub 2019 Oct 3.
Mining is one of the main economic activities in Mexico, and Hidalgo State is one of the main areas; however, this activity produces wastes, such as mine tailings, that are disposed in deposits and may be dispersed on the soils (e.g., agricultural soils). In this study, the concentrations of As and heavy metals in maize plants cultivated in a greenhouse in two soils influenced by tailings were evaluated. Plants were grown for 165 days in the soils (one of them more polluted due to a closer distance to the tailings) and one control soil close to the study zone. Plants' growth was evaluated, and after harvesting, they were divided in six parts: root, stalk, plant leaves, cob sheath, corncob and grains. Plants showed depressed development: small height, slow growth and physiological cob immaturity. Assimilation of As and heavy metals by plants was influenced by the concentration of the contaminants but also by the availability of nutrients. Important concentrations of the metals were recorded in the harvestable parts (grain, stalk and cob sheath). The order of accumulation was Zn > Fe > Pb > As > Cd. Cadmium was not detected in grains, but a maximum concentration of As at 1.02 mg/kg and Pb at 3.9 mg/kg was measured in the dry grain. These As and Pb concentrations do not comply with CODEX Alimentarius standards for maize, which states that the cob must be free of heavy metals. In addition, Pb also exceeds the limits established by the Mexican NOM-247-SSA1-2008 regulation.
采矿是墨西哥的主要经济活动之一，伊达尔戈州是主要地区之一；然而，这项活动会产生废物，如尾矿，这些废物被堆放在沉积物中，可能会扩散到土壤（如农业土壤）上。在本研究中，评估了在受尾矿影响的两种土壤的温室中种植的玉米植株中砷和重金属的浓度。植株在这些土壤（其中一种由于距离尾矿较近而污染更严重）以及靠近研究区域的一种对照土壤中生长了165天。对植株的生长进行了评估，收获后，将它们分为六个部分：根、茎、叶、苞叶、玉米穗轴和籽粒。植株表现出发育受阻：株高矮小、生长缓慢且玉米穗生理不成熟。植物对砷和重金属的吸收不仅受污染物浓度的影响，还受养分有效性的影响。在可收获部分（籽粒、茎和苞叶）记录到了较高浓度的金属。积累顺序为锌＞铁＞铅＞砷＞镉。籽粒中未检测到镉，但在干籽粒中测得砷的最高浓度为1.02毫克/千克，铅的最高浓度为3.9毫克/千克。这些砷和铅的浓度不符合食品法典委员会关于玉米的标准，该标准规定玉米穗轴必须不含重金属。此外，铅也超过了墨西哥NOM - 247 - SSA1 - 2008法规规定的限值。
