**Preface to "Artisanal and Small-Scale Gold Mining (ASGM) Related Environmental and Health Problems"**

Artisanal and small-scale gold mining (ASGM) activity has been undertaken in developing countries for socio-economic reasons; however, it accounts for the largest anthropogenic source of mercury (Hg) emission, releasing over 700 metric tons into the atmosphere, in addition to approximately 800 metric tons into land and water annually, exposing both ASGM miners and nearby communities to the mercury. Moreover, heavy metals other than Hg have been released into the environment as a result of the ASGM process. Therefore, ASGM causes environmental disruption and health problems not only in ASGM communities but across the whole nation too because of the risks it poses.

Several studies related to Hg pollution caused by ASGM activity and its impact on the environment and health have been published; yet, there is a need to explore the hazards of ASGM due to the nature of this global problem.

Therefore, we initiated this Special Issue to explore research related to the environmental and health problems posed by ASGM across the world, as well as its economic impacts and the proposed sustainable solutions to ASGM problems. A total of 20 papers are published and introduced in this book, covering regions including Southeast Asia, South America, and South Africa, in addition to papers covering more general ASGM issues.

#### *Southeast Asia*

Indonesia is known as the country with the most prevalent ASGM activities in Southeast Asia (SEA). The first paper describes the ASGM profile of Indonesia in a narrative literature review, including the Hg problem, occupational hazards, the environmental and health impacts caused by ASGM, and recommendations on the management of the ASGM sector of Indonesia.

The second and third papers investigate the transformations of roving camp-type ASGM activities in Katingain Regency, Central Kalimantan Province, using the Sentinel-1 time-series dataset, with the results are expected to contribute to environmental governance actions.

Additionally, this Special Issue included seven papers on research conducted using multiple approaches to analyze ASGM in Gorontalo Province, Indonesia. Papers four and five assess the transformation of camp-type ASGM in Bone Bolango Regency using remote sensing imagery and field surveys. These findings shed light on the community's socio-environmental pollution, allowing for better environmental governance. According to the findings of paper six's household survey of rural villagers residing close to ASGM in Bone Bolango Regency, diverse choices about work prospects are found to be useful in delinking reliance on ASGM, decreasing health hazards and improving the rural villagers' livelihoods. Paper seven reports on river basin sediment contamination with toxic elements at ASGM sites, such as Hg, zinc (Zn), lead (Pb), and arsenic (As). Paper eight suggests *P. vittate* as a bioindicator for assessing the environmental pollution caused by Pb and Hg. Moreover, paper nine examines the atmospheric Hg attachment to tree bark and finds that the tree types employed in the study may be used as biomonitors of atmospheric Hg pollution in ASGM regions. Finally, paper 10 explores geomedical science using geogenic samples, hair samples, and health evaluations, and finds that geogenic concentrations of specific components match their accumulation.

Myanmar is also a SEA country with abundant ASGM activities and high Hg usage due to poor

national ASGM sector management and little environmental and health research, aggravating the problems. Paper 11 presents a case study conducted during the COVID-19 pandemic, providing the first transdisciplinary online health assessment of the ASGM community of Mandalay Region, Myanmar, which is suggested as an effective regular long-term health assessment of the residents following the physical health surveys in ASGM areas.

Paper 12 reviews the Hg pollution in ASGM areas of Myanmar and some other SEA countries, exploring the severe Hg contamination characteristic of the ASGM process, specifically the gold amalgamation stage. Paper 13 summarizes the ASGM profiles of SEA countries and the consequent environmental, community health, and socioeconomic problems, introducing a sustainable approach to alleviate severe ASGM issues and improve environmental governance and community health in ASGM communities in SEA.

#### *South America*

Four studies focused on various regions of South America—Ecuador, Brazil, and Peru—are included in this Special Issue. Paper 14 investigates the possible composition and distribution of toxic element contamination in various metallic deposits, primarily from ASGM districts throughout Ecuador and a major oilfield in the Ecuadorian Amazon basin, as well as how mismanagement of local mines and petroleum exploitation projects results in environmental degradation. Paper 15 evaluates the sustainability of cocoa growing in the mining district of Ponce Enriquez, Ecuador, in connection to mining operations, which may pose health concerns to humans and the environment.

Paper 16 proposes a methodology to quantify the average economic health impact of the extraction of gold by ASGM in Brazil, converting it into monetary losses. This method can assess ASGM's environmental impact.

Paper 17 analyzes the amount of methylmercury that people in the headwaters of the Manu River and Manu National Park in southwestern Peru are exposed to. The paper also looks into the link between people's exposure to methylmercury and the functioning of their brains.

#### *South Africa*

Paper 18 represents a case report derived from a cross-sectional study of Pb exposure in incarcerated juveniles in greater Johannesburg, South Africa, and argues that illegal gold mining has a negative impact on the livelihoods of young males, with particular attention paid to education, health, and violent behavior.

#### *General*

Paper 19 is a bibliometric analysis on artisanal and small-scale mining (ASM), showing that the current research from 2010 onwards has focused on (i) the social factors affecting ASM, (ii) the effects of ASM on the environment, (iii) Hg contamination and its effect on health and the environment, and (iv) ASM as a livelihood. Ecotourism in artisanal mining regions has also become a major trend in the last decade, promoting sustainable development as well as the preservation and utilization of geological and mining heritage. In paper 20, which is a systematic review, the authors argue that occupational Hg exposure seriously affects miners' health and wellbeing, possibly resulting in neuro-psychological disorders, including ataxia, tremor, or memory problems; however, the major reported symptoms of the previous studies were largely unspecific, such as hair loss or pain.

To summarize, these Special Issue studies posit that: (1) ASGM activity using toxic elements, such as Hg and cyanide due to the lack of legal enforcement on ASGM sector, is still widely practiced as an alternative livelihood in rural areas in many countries around the world; (2) ASGM has a negative impact on environmental ecosystems, causes occupational health problems for miners, and causes chronic health disorders in both ASGM communities and those living far from ASGM areas. However, some studies explore the specific potential bioindicators of environmental damage caused by ASGM to suggest sustainable solutions to its severe environmental and social problems.

We are grateful to all the authors for their important contributions, as well as Darija Žili´c at MDPI for facilitating the publication of this Special Issue. Our thanks go out to everyone who took part in the studies and to the workplaces that allowed us to study.

> **Masayuki Sakakibara, Win Thiri Kyaw, and José Luis Rivera Parra** *Editors*
