In the village of Matra, located in Haute-Corse, the legacy of an old arsenic mine continues to pose environmental and public health risks. The mine, which operated until the mid-1940s, has left behind persistent contamination in local water sources and aquatic life. Arsenic, a naturally occurring metal that is highly toxic in high concentrations, is still being detected in the area's water, raising concerns about the safety of the local water supply. The village is now working to address these issues, though the costs of remediation are expected to be significant. According to Mayor Michel Palmieri, water samples from Matra show an average arsenic concentration of about 20 micrograms per liter (µg/l), which is double the regulatory limit set for safe drinking water. To reduce exposure, the municipality plans to abandon a water intake located near the former mine entrance and instead use a second intake with lower arsenic levels—around 8 µg/l. Additionally, the local government is considering repairing the aging water infrastructure, including the water network, reservoir, and pipelines, as well as installing electronic meters to monitor and reduce leaks. These improvements are estimated to cost 3.3 million euros, not including taxes. A recent scientific study published in April 2026 highlights the ongoing circulation of arsenic between surface waters and groundwater near the former mine. Antoine Orsini, a hydrogeologist at the University of Corsica, explains that the mine historically extracted minerals used in various industries, including the production of chemical weapons. His research found that arsenic levels in nearby rivers can reach over 2,000 µg/l—more than 200 times the safe limit for drinking water. However, these high levels are measured in natural water environments, not at household taps. Despite this, the contamination is also evident in aquatic organisms, such as mosses, invertebrates, and fish, with higher concentrations found in the muscles, liver, gills, and bones of trout downstream from the mine. The immediate concern in Matra is ensuring that the water distributed to residents is safe. The World Health Organization warns that long-term exposure to inorganic arsenic through drinking water and food can lead to serious health issues, including cancer and skin damage. To address this, the proposed solution involves revising the village's water supply by excluding the intake near the former mine entrance. Replacing aging pipelines is also necessary to address wear and leaks. However, this presents additional challenges, as asbestos may be present in the old materials, potentially adding around one million euros to the project's cost. The mayor has suggested depositing these materials at the already polluted mine site as part of a broader water management strategy, emphasizing the need to determine who is responsible for the mine's environmental impact and the associated costs. The total estimated cost for the project is 3.3 million euros, excluding taxes, and could rise to four million euros when taxes are included. The project is still under evaluation, with the first tender responses received in mid-July. The municipality now faces the challenge of securing funding for these essential improvements, which would help ensure a safer water supply for the village. Meanwhile, the pollution from the mine site remains an ongoing issue, requiring continued attention and action.