We studied the fate of Cu in contaminated semiarid soils from two areas with different mining activities in central Chile. Several regression models were evaluated to use soil physicochemical characteristics to predict solubility, partitioning, and activity of Cu. Furthermore, we hypothesize that the type of Cu mining compound (smelter dust versus tailing sand) can be another important variable determining the bioavailability of Cu. In the studied neutral to alkaline soils, soil organic matter (SOM) enhanced Cu solubility most probably through the formation of organic complexes with dissolved organic C (DOC). As a consequence, Cu solubility and partitioning were better explained by DOC concentration than by SOM content. On the other hand, Cu activity was mainly related to soil pH and was not affected by DOC. Although we found differences between the two study areas, Cu solubility and partitioning might not be as dependent upon the origin of the Cu mining compound as upon other physiochemical characteristics that influence the concentration and characteristics of DOC. Total Cu, pH, and DOC would be the most important variables to consider on Cu solubility, however, data about the nature of SOM may certainly improve the prediction models. Thus, multiple binding site models between Cu and DOC should be studied to improve predictions of Cu solubility.

No abstract

No abstract

Several previous studies highlighted the importance of using field-collected soils instead of artificially spiked contaminated soils for phytotoxicity tests. However, the use of field-collected soils presents several difficulties for interpretation of results, due to presence of various contaminants in the soil and unavoidable differences in the physicochemical properties of the tested soils. The objective of this study was to estimate thresholds of copper phytotoxicity in topsoils of 27 agricultural areas historically contaminated by mining activities in Chile. We performed standard emergence and early growth (21 days) tests (OECD 208 and ISO 11269-2) with lettuce. The response of lettuce was best explained by Cu toxicity and P deficiency. Growth of lettuce was related to soil total Cu concentration and Olsen-P and was not affected by soluble Cu (extractable by 0.1 M KNO 3 ) or Cu 2+ free ion activity of the soil solution. Thus, lettuce has a limited applicability for metal toxicity assessment in metalcontaminated soils, due to sensitivity of its response to P deficiency. However, it was possible to determine toxic thresholds for shoot concentrations of Cu in lettuce for responses of shoot and root length, suggesting that shoot concentrations of Cu in lettuce can be useful as indicators of Cu toxicity even in soils with a wide range of nutrient concentrations.

No abstract

No abstract

Human exposure to trace elements has been a large concern due to the potential health issues. Accordingly, this study aimed to compare the concentrations of arsenic, copper, and zinc in the edible parts of vegetables grown in a mining-agricultural area and in an exclusively agricultural area and to compare the potential human health risks of consuming vegetables from both areas. The consumption habits of the studied population were extracted from the 2010 National Alimentary Survey of Chile. In most cases, the concentrations of trace elements in the edible tissues of vegetables (lettuce, spinach, garlic, onion, carrot, potato, sweet corn, and tomato) were higher in the mining-agricultural area than those in the control area. This difference was most pronounced for leafy vegetables, with arsenic being the trace element of concern. Specifically, the arsenic concentrations in the edible tissues of lettuce and spinach were 8.2- and 5.4-fold higher, respectively, in the mining-agricultural area than in the control area. Lettuce was the vegetable of concern due to its relatively high consumption and relatively high concentration of trace elements. Nevertheless, there was no health risk associated with vegetable consumption in either the mining area or the control area because none of the HQ values surpassed 1.0.

Social unrest is on the rise worldwide amid deepening inequalities, environmental degradation, and job crises worsened by increasing social-environmental conflicts. In Chile, a social revolt in 2019 resulted in a national referendum in 2020. An ample majority (78.3% vs. 21.7%) voted to draft a new constitution to replace the current constitution drawn up under dictatorship. The result led to the emergence and empowerment of several organizations demanding an “ecological constitution”. In this context, we aim to analyze: (1) the main social-environmental conflicts in Chile and how they are related to the country’s current constitution, and (2) the potential drafting of an ecological constitution that addresses these conflicts. Across different industries in Chile, we observed common problems that are intrinsically related to the current constitution. This relationship seems to be perceived by Chilean citizens since a survey carried out in May 2021 found 79% support for an ecological constitution. Moreover, 105 of the 155 delegates to the constitutional convention proposed three or more environmental principles to be included in the new constitution. A potential ecological constitution entails principles that would improve the current situation of social-environmental conflicts in Chile. Based on our analysis, we recommend the establishment of watershed-based “territorial rights” in the new Chilean constitution to improve sustainability and environmental justice.