The derelict Remance gold mine is a possible source of pollution with potentially toxic elements (PTEs). In the study area, diverse mine waste has been left behind and exposed to weather conditions, and poses risks for soil, plants and water bodies, and also for the health of local inhabitants. This study sought to perform an ecological and health risk assessment of derelict gold mining areas with incomplete remediation, including: (i) characterizing the geochemical distribution of PTEs; (ii) assessing ecological risk by estimating the pollution load index (PLI) and potential ecological risk index (RI); (iii) assessing soil health by dehydrogenase activity; and iv) establishing non-carcinogenic (HI) and carcinogenic risks (CR) for local inhabitants. Soil health seems to depend on not only PTE concentrations, but also on organic matter (OM). Both indexes (PLI and RI) ranged from high to extreme near mining and waste accumulation sites. As indicated by both the HI and CR results, the mining area poses a health risk for local inhabitants and particularly for children. For this reason, it will be necessary to set up environmental management programs in the areas that are most affected (tailings and surrounding areas) and accordingly establish the best remediation strategies to minimize risks for the local population.
<p>The inadequate treatment of waste materials in mine tailings, the closure stage not carried out correctly, carries risks due to the residues of potentially toxic elements (PTEs) that it may contain. In Panama, environmental regulations are recent, and even so the regulations are not strictly enforced, leaving a problem for the adjacent communities. Such is the case of the Remance Gold Mine, in Veraguas, Panama; this area has been exploited intermittently for over a hundred years, by different companies; the last period of exploitation was between 1989 and 1999, through a cyanidation process to extract the precious metal. Currently three tailing dams with mining waste are exposed to climatic conditions such as rain and wind, in addition to this, within the mine area and its surroundings live peasants who carry out subsistence activities such as agriculture and livestock. The purpose of this study was to evaluate the remaining potentially toxic elements and the persistence of cyanide in the tailings, and whether the remaining quantity represents a risk to human health and the environment, according to current environmental regulations in Panama and America. For this purpose, samples have been taken from the tailings and adjacent areas that could be directly related to the cyanidation process, geochemical analysis such as pH, CEC, conductivity, organic matter, potentially toxic elements and total cyanide have been carried out. The most concerning aspects of the results obtained here have been the contents of Ba (between 55 and 610 mg kg<sup>-1</sup>), Zn (between 12 and 153 mg kg<sup>-1</sup>), Sb (between 0.6 and 25.5 mg kg<sup>-1</sup>) and Hg (between 0.1 and 3.2 mg kg<sup>-1</sup>), which, according to the criteria of land use quality standards in Panama and American countries, correspond to values above the permissible limits for agricultural and residential land use. Meanwhile the levels of As (between 17.3 and 5030 mg kg<sup>-1</sup>) and Cu (between 5.4 and 403 mg kg<sup>-1</sup>) are higher than the legally established values for industrial land use. Far more significant are the values for total cyanide (between 1.4 and 518 mg kg<sup>-1</sup>), revealing the persistence of this chemical over time. These cyanide values are far higher than those reported in the literature for solid tailings from an abandoned gold mine and the values for gold mine tailings in the Americas, thus representing a serious threat to the environment.</p>
<p><strong>Abstract:</strong> The Remance gold mine, in Veraguas, Panama, has been widely affected by mining activity, whose last exploitation period was between 1989 and 1999, by the company Minera Remance S.A. Previous studies have reported that stream sediments are severely polluted; terrace sediments represented a serious ecological risk and stream sediments a high ecological risk represented by the presence of high concentrations of potentially toxic elements (PTEs. In addition, the study also showed that soil health, evaluated through the DHA (dehydrogenase activity) factor, is more affected in the terrace sediments and stream sediments than in the soils. The carcinogenic and non-carcinogenic risk assessment was exceeded for children into a recreational setting in areas of major mining activity; for adults, the carcinogenic risk is also exceeded mainly by the ingestion route. The area is inhabited by peasants, who carry out their daily activities, such as recreation and subsistence agriculture, reason why it is necessary to carry out bioaccessibility studies on these materials to properly assess the real risks for this population.</p> <p>The objective of this study has been to determine the oral bioaccessibility of PTEs in terrace sediments and stream sediments to evaluate the health risks that these materials represent in case of accidental ingestion in a recreational setting. The following PTEs were analysed: were determined in the pseudo-total fraction by ICP-OES: Cu, As, Zn, Sb and Ba. The oral bioaccessibility test was performed by the UBM method and the concentrations of the PTEs in the gastric and gastrointestinal phase were determined by ICP-OES. The percentage of bioaccessibility (% BAF) for the PTEs, and the carcinogenic and non-carcinogenic risks by ingestion in all fractions were evaluated for children and adults in a recreational setting.</p> <p>The results show that terrace sediments have higher total concentration of PTEs than stream sediments, while the oral bioaccessibility is higher in stream sediments than in terrace sediments and is higher in the gastric phase than in the gastrointestinal phase. The order of oral bioavailability was as follows: Cu>Zn>Ba>As>Sb.</p> <p>As for the non-carcinogenic risk by ingestion, the maximum permissible limit (HI=1) is exceeded for the sum of the studied PTEs in the pseudo-total fraction of stream sediments and terrace sediments in a recreational setting for children, but not in the gastric and gastrointestinal fractions. The maximum permissible limit for carcinogenic risk (1x10<sup>-5</sup>) is exceeded by As for adults and children in all stream and terrace sediments in the pseudototal fraction, and for children in the gastro and gastrointestinal fraction in the stream sediments of &#8220;El Toro&#8221; stream and terrace sediments of &#8220;Veneno&#8221; stream below one of the mine tailings accumulations. Therefore, recreational activity in these streams is not recommended.</p> <p><strong>Keywords</strong>: bioaccesibility, potentially toxic elements, ingestion, stream sediments, terrace sediments, gold mine, Panama</p>
The supply of water to populations is a basic need that has been threatened more frequently in recent years due to climate change, which renders seeking other sources of water essential. The hydrochemistry of the groundwater of the aquifer located in the UTP Tocumen was characterized by previous research to determine its possible use as a source of drinking water and irrigation water. The objective of this study is to characterize the soil and rock hosting the aquifer to acquire more information about them with a view to possibly exploit an alternative source of drinking water. To this end, a 10-m-depth survey was conducted to obtain soil and rock samples from the area, and to characterize geotechnical and geochemical parameters. 2D electrical resistivity tomography was used to create a lithological model of the aquifer and to correlate the data. Soil is residual of the technosol type, considered permeable with a transmissivity level that favors rainwater infiltration, followed by the soil–rock interface, where rock is weathered. It´s followed by a sedimentary rock corresponding to marly siltstones with a certain degree of tectonic fractures that allow water infiltration and its accumulation in the rocks, constituting the aquifer. The 2D electrical resistivity suggests two water accumulations: a superficial and a deep one. There was a good correlation between the aquifer water’s chemistry and the rock geochemistry.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.