Luiz de Queiroz College of Agriculture, University of São Paulo (ESALQ-USP), Av. Pádua Dias 11, CEP 13418-900 Piracicaba, São Paulo, Brazil.
Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521, United States; Department of Environmental Sciences, University of California, Riverside, CA 92521, United States.
Mar Pollut Bull. 2021 May;166:112267. doi: 10.1016/j.marpolbul.2021.112267. Epub 2021 Mar 19.
The role of Fe oxyhydroxides dynamic on metal bioavailability was studied in the Rio Doce estuary after the largest mining disaster in the world. Soon after the disaster in 2015, metals were associated with Fe oxyhydroxides under a redox-active estuarine environment. Our results indicate that organic matter inputs from plant colonization on deposited tailings over estuarine soils led to a reductive dissolution of Fe oxyhydroxides within two years. Soil pseudo-total Fe content decreased by 70% between 2015 and 2017, while the total metal contents (Cr, Cu, Ni, Pb, and Zn) decreased by 79% in the soil. The losses of Fe and metals coupled to changes in Fe oxides crystallinity reveal a future ephemeral control of Fe oxyhydroxides over metal immobilization. Our results suggest a potential chronic contamination at the estuary and points to an aggravating scenario for the following years due to the increasing dominance of poorly crystalline Fe oxyhydroxides.
本研究探讨了世界最大采矿灾难后里约热内卢河口中铁氧氢化物对金属生物有效性的作用。2015 年灾难发生后不久，金属与铁氧氢化物在具有氧化还原活性的河口环境中有关联。我们的结果表明，在河口土壤上沉积的尾矿上植物定殖所带来的有机质输入，导致铁氧氢化物在两年内发生还原溶解。2015 年至 2017 年间，土壤中假全铁含量下降了 70%，而土壤中总金属含量（Cr、Cu、Ni、Pb 和 Zn）下降了 79%。铁和金属的损失与铁氧化物结晶度的变化相关，这揭示了铁氧氢化物对金属固定的未来短暂控制。我们的研究结果表明，河口存在潜在的慢性污染，并指向未来几年因结晶度差的铁氧氢化物占主导地位而加剧的情况。
