Facultad de Ingeniería, Universidad Tecnológica del Chocó, Carrera 22 No.18B-10, Quibdó, Colombia; Facultad de Ingeniería, Universidad de Medellín, Carrera 87 No. 30-65, Medellín, Colombia.
Departamento de Química, Facultad de Ciencias Básicas, Grupo de Agua, Química Aplicada y Ambiental, Universidad de Córdoba, Carrera 6 No. 76-103, Montería, Córdoba, Colombia.
Chemosphere. 2020 Nov;258:127319. doi: 10.1016/j.chemosphere.2020.127319. Epub 2020 Jun 9.
Total mercury (THg) and methylmercury (MeHg) were studied in sediments from 27 abandoned gold mining ponds (AGMPs) through small-scale artisanal gold mining in the district of San Juan in Chocó region of Colombia. The AGMPs were abandoned in the last century (1997) and were grouped into three distinct groups (2-6; 7-12; 13-20 years). Overall concentration (in ng g) pattern of THg in sediments varied from 39.06 to 1271.32 (avg. 209.57) with 174.81 (13-20 years), 205.56 (7-12 years) and 248.33 (2-6 years) respectively. MeHg concentrations accounted for 3.3-10.9% (avg. 6.5%) of THg and were significantly correlated with THg during all periods. Correlations between organic matter (OM) vs MeHg and THg were negative in the oldest pools, signifying a "dilution effect" or "natural burial" of THg and MeHg. Results for sequential extraction indicate that the fraction of elemental Hg (Hg-e) and organo chelated Hg (Hg-o) represent the main chemical forms of Hg in the sediments, regardless of the abandonment period, whereas the bioavailable fraction was only 0.12-1.65% of THg. The significant statistical relationship between MeHg, THg and OM suggests that these parameters control the distribution, mobility, toxicity and bioavailability of Hg in the sediments of these abandoned ponds. Evaluation of THg with sediment quality guidelines indicates that the values are on the higher side for Threshold effect concentration and Upper continental crust. Comparing of MeHg with many other regions outside Colombia is a worrying factor and needs immediate attention to protect the human health.
在哥伦比亚乔科地区圣胡安区，通过小规模的手工采金，研究了 27 个废弃金矿池塘（AGMP）中的总汞（THg）和甲基汞（MeHg）。这些 AGMP 在上世纪（1997 年）被废弃，并分为三组（2-6 年、7-12 年和 13-20 年）。沉积物中 THg 的总浓度（ng g）模式变化范围为 39.06-1271.32（平均值 209.57），分别为 174.81（13-20 年）、205.56（7-12 年）和 248.33（2-6 年）。MeHg 浓度占 THg 的 3.3-10.9%（平均值 6.5%），在所有时期均与 THg 呈显著相关。在最古老的池塘中，有机质（OM）与 MeHg 和 THg 之间的相关性呈负相关，表明 THg 和 MeHg 存在“稀释效应”或“自然埋藏”。顺序提取结果表明，无论废弃时间如何，元素汞（Hg-e）和有机螯合汞（Hg-o）是沉积物中汞的主要化学形态，而生物可利用部分仅占 THg 的 0.12-1.65%。MeHg、THg 和 OM 之间的显著统计关系表明，这些参数控制了这些废弃池塘沉积物中 Hg 的分布、迁移性、毒性和生物可利用性。利用沉积物质量准则评估 THg 表明，其数值在阈值效应浓度和上地壳的较高范围内。与哥伦比亚以外的许多其他地区的 MeHg 相比，这是一个令人担忧的因素，需要立即关注以保护人类健康。
