Study Links Metal Exposure to Cognitive Risks

A recent study by Mexico’s National Institute of Public Health (INSP) reports a possible reduction in intellectual function among schoolchildren in rural communities of Molango, Hidalgo, an area with long-standing mining activity. The findings add new evidence to concerns about environmental exposures in regions where economic activity and public health are closely tied.

Mining provides essential materials for modern life, but it can also create major environmental and public health risks. Mining operations globally frequently lead to environmental damage, including erosion, deforestation, water pollution, and loss of biodiversity, which in turn can negatively affect the health of nearby communities. While mining companies have a responsibility to protect their own employees from disease, the scope of their obligation toward surrounding populations presents an intricate challenge.

Mexico's mining sector has historically played a crucial role in the country's economy. In 2024, mining generated over 416,000 direct jobs and 2.6 million indirect positions, with wages averaging 28% above the national level, reports MBN. The sector contributed 8.7% of industrial GDP, produced more than MX$259 billion (US$14.2 billion) in economic output, and delivered MX$45 billion in fiscal contributions. Despite this, the rights to life, health, and a safe environment for communities living near mining operations have not been fully guaranteed, reports the INSP.

Children are more vulnerable than adults to the impacts of large-scale mining, particularly from birth to age five, when key physical development occurs. Exposure to chemical residues can have more severe and lasting effects in children, with potential consequences that extend throughout their lives, reports UNICEF.  

The research, published in the peer-reviewed journal Exposure and Health, examined the presence of multiple metals in fine particulate matter (PM2.5) and their potential impact on cognitive performance. While earlier work in the early 2000s focused mainly on manganese exposure, the recent analysis broadens the scope by evaluating mixed-metal exposure using advanced statistical tools designed for complex environmental mixtures.

Researchers analyzed data from 108 children between seven and 11 years old and assessed intellectual performance through the WISC-R scale. According to the study, exposure to a mixture of metals in the air was associated with a reduction of up to 5.32 points in performance IQ, which covers functions such as planning, visual reasoning, and processing speed. The authors noted that these functions are essential for learning and later workplace development, underscoring the long-term implications of early environmental exposures for human capital formation.

The study recommends continued assessment of airborne metals, especially in mining regions where workers and families may face sustained exposure. Exposure to PM2.5 has also been linked to a wide range of health effects, particularly in children. Because these smaller particles can reach the deeper areas of the lungs, they are associated with respiratory and cardiovascular impacts, as well as increased hospital visits and activity limitations. PM2.5 is considered one of the pollutants most strongly tied to global health burdens, according to the World Health Organization.

INSP researchers highlight the need to strengthen environmental monitoring and risk communication in rural areas. Their recommendations include regular air-quality assessments, the use of exposure biomarkers in children, and the development of locally tailored communication strategies. These measures aim to improve awareness, support preventive action, and safeguard communities whose economic conditions depend on resource extraction.