Mining is one of the oldest economic activities of mankind. Within this activity, artisanal and small-scale gold mining (ASGM) is one of the most studied sectors due to its high level of environmental contamination and the social problems it causes. In recent years, ASGM in the northern Amazon of Ecuador has increased significantly, and studies that describe its current situation and impact are scarce. In this sense, the present study aimed to analyze the current status and socioenvironmental impacts caused by ASGM gold mining activities in the Cascales canton in the province of Sucumbíos in northeastern Ecuador. The methodological tools used in the present study were a literature review of scientific and gray literature, field visits to assess perceived impacts and an expert judgment to discuss the results and establish challenges. The main results indicate that illegal and informal activities continue to be carried out in the upper zone of the Cascales and Duvino rivers; 90% of local miners still use mercury in this activity, although it is legally prohibited. Among the main impacts evidenced are the contamination of water bodies, soil and atmosphere due to the use of mercury and disturbance to flora and fauna due to the use of machinery in the exploration process. Finally, the government should focus efforts on strengthening public policies to socialize the importance of good environmental practices in ASGM and the effects of the impacts on human health and environmental issues, all this with the support of social actors, such as ministries, universities, NGOs, ASGM associations and private enterprise.

Artisanal and small-scale gold mining (ASGM) plays a crucial role in global gold production. However, the adoption of poor mining practices or the use of mercury (Hg) in gold recovery processes has generated serious environmental contamination events. The focus of this study is assessing the concentration of Hg in surface waters within the coastal region of Ecuador. The results are used to conduct a human health risk assessment applying deterministic and probabilistic methods, specifically targeting groups vulnerable to exposure in affected mining environments. Between April and June 2022, 54 water samples were collected from rivers and streams adjacent to mining areas to determine Hg levels. In the health risk assessment, exposure routes through water ingestion and dermal contact were considered for both adults and children, following the model structures outlined by the U.S. Environmental Protection Agency. The results indicate elevated Hg concentrations in two of the five provinces studied, El Oro and Esmeraldas, where at least 88% and 75% of the samples, respectively, exceeded the maximum permissible limit (MPL) set by Ecuadorian regulations for the preservation of aquatic life. Furthermore, in El Oro province, 28% of the samples exceeded the MPL established for drinking water quality. The high concentrations of Hg could be related to illegal mining activity that uses Hg for gold recovery. Regarding the human health risk assessment, risk values above the safe exposure limit were estimated. Children were identified as the most vulnerable receptor. Therefore, there is an urgent need to establish effective regulations that guarantee the protection of river users in potentially contaminated areas. Finally, it is important to continue investigating the contamination caused by human practices in the coastal region.

Gold mining activity is a source of supply in many areas of the world, and especially in developing countries, it is practiced illegally and by applying unsafe techniques. Particularly in Ecuador, artisanal and small-scale gold mining (ASGM) is widespread, and it is based on the use of toxic substances, such as mercury (Hg), in gold recovery. Hg is a heavy metal that is water-insoluble, which, once mobilized, poses a threat to both the environment and human health. This study analyzes Hg concentrations in the six provinces of Napo, Sucumbíos, Orellana, Pastaza, Morona Santiago, and Zamora Chinchipe of the Ecuadorian Amazon region to conduct a human health risk assessment. Significant differences in Hg levels were found between provinces, but concentrations were below MPL imposed by Ecuadorian regulations everywhere. Nevertheless, a worrisome picture emerges, especially with regard to the most vulnerable receptors represented by the child population. There are multiple factors of incidence that may affect the possible future development of the phenomenon, and with reference to the social, economic, and environmental context of the region, it can be concluded that it may be appropriate to plan further investigation to arrive at a more comprehensive assessment. The results of this study can be used by decision makers to plan further investigation and to implement monitoring networks, risk mitigation strategies, and groundwater protection measures.

In Ecuador, illegal gold mining has led to significant environmental impacts, with the release of harmful elements such as mercury (Hg) into the environment. Mercury, due to its physical–chemical characteristics and the transport elements involved between different environmental matrices, can easily percolate through the soil and reach groundwater. The purpose of this study was to evaluate the mercury concentration levels in the Andean region in order to perform a human health risk assessment. For this purpose, 175 water samples were analyzed, of which 9.71% exceeded the maximum permissible limit (MPL) established for drinking water in accordance with Ecuadorian regulations. The risk analysis was conducted by applying two approaches: deterministic and probabilistic. The deterministic approach involves a specific analysis based on the calculation of the risk quotient (HQ) and risk index (HI) for both receptors (adults and children) and scenarios (residential and recreational) considered; the probabilistic approach is based on the use of stochastic simulation techniques. The results obtained from the two approaches show a discrepancy, with the deterministic analysis providing more conservative results; however, they coincide in showing higher risk for the child population; decision-makers could use these results to identify areas to be monitored and plan more detailed investigation plans.

Artisanal and Small-scale Gold Mining (ASGM) is a source of supply in many areas of the world, especially in developing countries. This is often carried out illegally using toxic substances such as mercury. Mercury, due to its chemical–physical properties and the transport factors involved between the different environmental matrices, can percolate through soil and from surface water to groundwater. The objective of this study was to conduct a human health risk assessment. For this purpose, a screening of mercury concentrations was carried out, collecting 67 water samples at selected points, and a risk assessment was performed applying both a deterministic and a probabilistic approach. A deterministic approach is a specific analysis based on determining the values of the risk quotient (HQ) and the risk index (HI) for each receptor category (adults and children) and scenario (residential and recreational) considered; a probabilistic approach is based on stochastic simulation techniques and the evaluation of the statistical quantities. There was found to be a discrepancy between the results provided by the two approaches, with the deterministic approach suggesting a more worrisome picture. However, in general, the results showed a greater exposure in the provinces of El Oro and Esmeraldas, and a greater vulnerability of child receptors.

La minería de oro es una de las industrias más destructivas del mundo. Los impactos socio-ambientales generados por la minería aurífera artesanal pueden afectar gravemente al en-torno natural y social. Es importante plantear desafíos a las autoridades competentes para que controlen y regulen las actividades mineras auríferas. El objetivo principal de este estudio se centró en evaluar los impactos socio-ambientales ocasionados por la minería aurífera artesanal en la parroquia El Dorado de Cascales, provincia de Sucumbíos, en la zona norte del territorio ecuatoriano. Previo a la evaluación, se analizó la situación actual en la zona de estudio. Para responder a los objetivos, se realizó una revisión bibliográfica de literatura científica y gris, acompañada de trabajo de campo (observación directa y entrevistas). Los resultados indicaron que el componente biótico y abiótico fueron los mas afectados por la actividad minera, debido a que la mayoría de los mineros utilizan técnicas rudimentarias, además se evidenció el uso de mercurio en los procesos de extracción de oro.