Artisanal and Small Gold Mining and Petroleum Production as Potential Sources of Heavy Metal Contamination in Ecuador: A Call to Action

Abstract

Mining and petroleum production are the source of many elements and base materials fundamental for our modern way of life. The flip side of these keystone industries is the environmental degradation they can cause if not properly managed. Metallic mining and petroleum production can contaminate the local ecosystem with sediments, chemicals used in the industrial processes and heavy metals, part of the metallic ore or oil reservoir. The objective of this project was to analyze the spatial distribution of the presence of different potentially hazardous elements that make up the metallic deposits and oil reservoirs in Ecuador, focused mainly on artisanal and small-scale gold mining (ASGM) districts. Additionally, we were interested in analyzing this information under the local political and administrative contexts which are key to determining how likely it is that mismanagement of the local mineral deposits and petroleum exploitation projects will end up causing environmental degradation. An extensive and intensive literature search was conducted for information on the presence and concentration of 19 potentially harmful elements. We analyzed data on 11 metallic deposits throughout Ecuador and a major oilfield in the Ecuadorian Amazon basin. We used geographic information systems to analyze the spatial distribution of these reservoirs and their mineral compositions. The results indicated a widespread distribution and high concentration of elements potentially harmful for human health, such as mercury, cadmium and arsenic, throughout the metallic deposits in Ecuador. This is particularly true for long-exploited ASGM districts, such as Ponce-Enríquez, Portovelo-Zaruma and Nambija. This study highlights the importance of understanding geological diversity and its potential risks to better protect the biological diversity and public health of its inhabitants. Furthermore, we consider our work not as a call to stop ASGM mining nor petroleum production, but on the contrary as a strong call to plan every mining and petroleum production project considering these risks. Moreover, our work is a call to action by the local government and authorities to stop corruption and fulfill their duties overseeing the activities of mining and petroleum companies, stopping illegal mining, helping ASGM communities to improve their environmental standards, finding alternative income sources and protecting the local environment.

Gold Mining in the Amazon Region of Ecuador: History and a Review of Its Socio-Environmental Impacts

“…Over time, mining has come to play an important role in the economic growth and sustainable development of the country. History shows that there have been constant social struggles between indigenous movements and representatives of transnational corporations and government authorities in claiming their legitimate rights, such as free and informed citizen participation, guaranteed land tenure, and their self-definition as indigenous peoples and nationalities, which, according to Convention 169 of the International Labor Organization (ILO), guarantees collective human rights in the presence of mining projects carried out within the area they inhabit [15,16].…”

History, Socioeconomic Problems and Environmental Impacts of Gold Mining in the Andean Region of Ecuador

“…Similarly, this type of mining, characterized by the use of Hg and CN in its gold-extraction processes (a technique widely applied in countries such as Brazil, Colombia, Indonesia, Venezuela, and Zimbabwe), has meant that tailings contaminated with cyanide and heavy metals end up being discharged into water currents and the atmosphere [29,72], a fact that, due to poor management and technification, has caused the country several international problems. Such is the case of the Puyango-Tumbes river, shared with Peru, which was contaminated by traces of Hg coming from Portovelo-Zaruma [73,74]. The presence of illegal mining in the country, according to several informal workers, is because it represents their only source of income and that, in recent years, the country's poor economic conditions and climatic phenomena have encouraged them to carry out this activity.…”

“…The presence of illegal mining in the country, according to several informal workers, is because it represents their only source of income and that, in recent years, the country's poor economic conditions and climatic phenomena have encouraged them to carry out this activity. They also point out that, on several occasions, they have tried to legalize their activities but that the bureaucratic system has prevented them from doing so [32,74].…”

History, Current Situation and Challenges of Gold Mining in Ecuador’s Litoral Region

“…In Ecuador, the use of mercury for gold amalgamation is prohibited; however, its use is still very frequent in the country, such that the substance is spread by rivers and ravines [17]. In this regard, activist Nathalia Bonilla stated in 2020 that due to the increase in illegal mining activities during the pandemic, the water sources of San Lorenzo and Eloy Alfaro have become contaminated.…”

“…As a result, chemical pollution is produced on the banks of the water bodies that flow through the mining areas by processes that release substances such as mercury, cyanide, nitric acid, zinc, lead, arsenic, cadmium and manganese [11][12][13][14]. They can also affect aquatic diversity, terrestrial ecosystems and even people [15][16][17][18].…”