Instituto Patagónico para el Estudio de los Ecosistemas Continentales (IPEEC -CONICET), Boulevard Brown 2915, U9120ACD Puerto Madryn, Chubut, Argentina; Universidad Nacional de la Patagonia San Juan Bosco, Boulevard Brown 3051, U9120ACD Puerto Madryn, Chubut, Argentina.
Centro de Investigaciones Geológicas, Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de La Plata (CIG - CONICET - UNLP), Diagonal 113 # 275, CP1900 La Plata, Argentina.
Sci Total Environ. 2017 Oct 15;596-597:230-235. doi: 10.1016/j.scitotenv.2017.04.065. Epub 2017 Apr 21.
Heavy metal pollution that affects salt marshes is a major environmental concern due to its toxic nature, persistence, and potential risk to organisms and to human health. Mining waste deposits originated four decades ago, by the metallurgical extraction of heavy metals, are found near to the San Antonio salt marsh in Patagonia. The aim of the work was to determine the geochemical processes that control the distribution and concentration of Cu, Fe, Pb and Zn in the soils of this Patagonian salt marsh. A survey of the mining waste deposits was carried out where three dumps were identified. Samples were collected to determine soil texture, Eh pH, organic matter and metal contents and the soil mineralogical composition. The results shows that the soils developed over the mining waste deposits are predominantly reddish constituted mainly by iron oxide, hydroxide and highly soluble minerals such as Zn and Cu sulphates. The drainage from these deposits tends to move towards the salt marsh. Within the salt marsh, the highest concentrations of Cu, Pb and Zn occur in the sectors closest to the mining wastes deposits. The sulphide oxidation and the dissolution of the Cu, Pb and Zn sulphates could be the mainly source of these metals in the drainage water. The metals in solution that reach the salt marsh, are adsorbed by the organic matter and the fine fraction of the soils. These adsorbed metals are then remobilized by tides in the lower sectors of the marsh by desorption from the cations present in the tidal flow. On the other hand, Fe tends to form non soluble oxides, hydroxides and sulphates which remain as altering material within the mining waste deposit. Finally, the heavy metal pollutants recorded in the San Antonio salt marsh shows that the mining waste deposits that were abandoned four decades ago are still a source metal contamination.
重金属污染影响盐沼，因其毒性、持久性以及对生物和人类健康的潜在风险，成为一个主要的环境关注点。冶金提取重金属产生的采矿废物，于四十年前在巴塔哥尼亚的圣安东尼奥盐沼附近堆积。这项工作的目的是确定控制该巴塔哥尼亚盐沼土壤中 Cu、Fe、Pb 和 Zn 分布和浓度的地球化学过程。对采矿废物进行了调查，确定了三个倾倒场。采集了样本以确定土壤质地、Eh-pH、有机质和金属含量以及土壤矿物组成。结果表明，在采矿废物上发育的土壤主要由氧化铁、氢氧化物和高度可溶性矿物（如 Zn 和 Cu 硫酸盐）组成，呈红色。这些沉积物的排水倾向于流向盐沼。在盐沼内，靠近采矿废物的区域 Cu、Pb 和 Zn 的浓度最高。这些金属可能主要来源于硫化物的氧化和 Cu、Pb 和 Zn 硫酸盐的溶解。进入盐沼的溶解金属被有机物和土壤的细颗粒吸附。这些被吸附的金属随后通过潮汐从潮汐流中存在的阳离子解吸，在沼泽的较低区域被重新释放。另一方面，Fe 倾向于形成不溶性的氧化物、氢氧化物和硫酸盐，作为改变材料留在采矿废物中。最后，圣安东尼奥盐沼中记录的重金属污染物表明，四十年前废弃的采矿废物仍然是金属污染的一个来源。
