CONACYT-Estación Regional del Noroeste, Instituto de Geología, Universidad Nacional Autónoma de México, Colosio y Madrid s/n, 83000, Hermosillo, Sonora, Mexico.
Departamento de Ingeniería Química y Metalurgia, Universidad de Sonora, Blvd. Luis Encinas y Rosales s/n, 83000, Hermosillo, Sonora, Mexico.
Environ Sci Pollut Res Int. 2020 Jul;27(21):26605-26620. doi: 10.1007/s11356-020-09051-1. Epub 2020 May 6.
Generation, storage, and management of waste coming from industrial processes are a growing worldwide problem. One of the main contributors is the mining industry, in particular tailings generated by historical mining, which are barely maintained, especially in developing countries. Assessing the impact of a mining site to surrounding soils and ecosystems can be complex, especially when determining mobility and accessibility of the contaminants is required to perform ecological and human health risk assessment. As an effort to obtain information regarding mobility and accessibility of some potentially toxic elements (Zn, Pb, and As) from an historical mining site of northwestern Mexico, the abandoned mine tailings of San Felipe de Jesús in central Sonora and adjacent agricultural soils were investigated. Mobility and accessibility were assessed by means of sequential extraction procedures and using simulated physiological media. Additionally, an assessment of accidental oral intake was calculated considering the bioaccessible fractions. Results show that higher concentrations of contaminants were found in sulfide-rich tailings (Zn = 92,540; Pb = 21,288; As = 19,740 mg kg) compared with oxide-rich tailings (Zn = 43,240; Pb = 14,763; As = 13,401 mg kg). Concentrations in agricultural soils were on average Zn = 4755, Pb = 2840, and As = 103 mg kg. Zinc was mainly recovered from labile fractions in oxide-rich tailings (~ 60%) and in a lower amount from sulfide-rich tailings (~ 30%). Pb and As were mainly associated with residual fractions (80-95%) in both types of tailings. The percentage of mobile fractions (sum of water-soluble, exchangeable, and bound to carbonate fractions) in agricultural soils was as follows: Zn ~ 60%, Pb ~ 15%, and As ~ 70%. Regarding the phytoaccessible fraction, the studied elements in mine tailings and agricultural soil samples exceeded the threshold limits, except for As in agricultural soils. According to data obtained, toxic effects were also calculated. As for daily oral intake for non-carcinogenic effects in adults and children, only Pb and As exceeded reference dose values, especially in children exposed to sulfide-rich tailings and agricultural soils. Regarding carcinogenic effects of Pb and As, most of the samples were above acceptable risk values.
工业过程产生的废物的产生、储存和管理是一个全球性的问题。矿业是主要的贡献者之一，特别是历史采矿业产生的尾矿，这些尾矿几乎没有得到维护，尤其是在发展中国家。评估采矿地点对周围土壤和生态系统的影响可能很复杂，特别是在需要确定污染物的迁移性和可及性以进行生态和人类健康风险评估时。为了获取有关墨西哥西北部一个历史采矿场（索诺拉州中部圣费利佩德赫雷斯的废弃矿尾矿）中一些潜在有毒元素（Zn、Pb 和 As）的迁移性和可及性的信息，研究了废弃矿尾矿和相邻的农业土壤。通过连续提取程序和模拟生理介质来评估迁移性和可及性。此外，还考虑可生物利用部分计算了意外口服摄入的风险评估。结果表明，硫化物丰富的尾矿（Zn=92540；Pb=21288；As=19740 mg kg）中污染物浓度高于氧化物丰富的尾矿（Zn=43240；Pb=14763；As=13401 mg kg）。农业土壤中的平均浓度为 Zn=4755，Pb=2840，As=103 mg kg。锌主要从氧化物丰富的尾矿中的可提取部分（60%）中回收，而硫化物丰富的尾矿中的含量较低（30%）。Pb 和 As 主要与两种类型的尾矿中的残余部分（80-95%）相关联。农业土壤中可移动部分（水溶性、可交换和与碳酸盐结合部分的总和）的百分比如下：Zn60%，Pb15%，As~70%。关于植物可利用部分，尾矿和农业土壤样品中的研究元素除了农业土壤中的 As 之外，都超过了阈值限制。根据获得的数据，还计算了有毒效应。对于成人和儿童的非致癌性每日口服摄入量，只有 Pb 和 As 超过了参考剂量值，尤其是儿童暴露于硫化物丰富的尾矿和农业土壤中。对于 Pb 和 As 的致癌效应，大多数样品都超过了可接受的风险值。
