Europe's largest salt lake has become a reservoir of toxic metals after a century of salt extraction and poses serious threats

Europe's largest salt lake has become a reservoir of toxic metals after a century of salt extraction and poses serious threats.

Written by Romario Pereira of Carvalho

Published 16/10/2025 às 18:38

Lagoa Menor, Mining, Salt extraction, toxic metals

Image: AI-made artistic illustration

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Waste from old salt mines in Spain continues to contaminate the Mar Menor, Europe's largest salt lake. Even after mining ceased in the 1990s, toxic metals such as lead, arsenic, and mercury still threaten the local ecosystem.

A former mining industry that operated between the late 19th and 20th centuries near the Cartagena-La Unión mountain range in Spain left a troubling legacy. The exploitation of the region's salt reserves contaminated the Mar Menor, Europe's largest saltwater lagoon, located in Murcia. The site became a reservoir of toxic metals.

A recent study published in the journal Marine Pollution Bulletin investigated the excess of heavy metals accumulated in the lagoon.

Although the industry ceased operations in the 1990s, rain continued to carry mine waste, keeping contamination active.

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High concentrations of metals

Currently, the Mar Menor has high levels of lead, arsenic, zinc, mercury, copper and silver, exceeding recommended limits.

The largest concentrations are in the southern part of the lagoon, the region closest to the old mining channels.

Historical data shows that the highest levels of pollutants occurred around the middle of the 20th century.

Despite the ban on mining discharges into water bodies since 1955, urban sources and boat paints continued to release metals into the lagoon, worsening the environmental problem.

Environmental impacts and risks

Today, the concentration of metals in sediments is lower than in the past, but the accumulation still reaches tons.

These elements remain deposited at the bottom of the lagoon and could pose a future threat.

According to researcher Irene Alorda, from the Autonomous University of Barcelona (ICTA-UAB), the current impact does not directly affect living organisms, but it could increase over time.

This is because the combination of human pressures and environmental changes tends to worsen the situation.

Growing threat

The study warns that climate change, eutrophication and sediment suspension can release metals back into the ecosystem.

This reactivation would put marine fauna at risk and increase the effects of contamination.

The research concludes that historical pollutants, combined with current environmental changes, can intensify the degradation of the lagoon.

Therefore, the authors advocate new conservation and monitoring strategies to protect the Mar Menor and avoid irreversible damage to the European ecosystem.

With information from Galileu Magazine.

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Europe's largest salt lake has become a reservoir of toxic metals after a century of salt extraction and poses serious threats.

Waste from old salt mines in Spain continues to contaminate the Mar Menor, Europe's largest salt lake. Even after mining ceased in the 1990s, toxic metals such as lead, arsenic, and mercury still threaten the local ecosystem.

High concentrations of metals

Environmental impacts and risks

Growing threat

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Europe's largest salt lake has become a reservoir of toxic metals after a century of salt extraction and poses serious threats.

Waste from old salt mines in Spain continues to contaminate the Mar Menor, Europe's largest salt lake. Even after mining ceased in the 1990s, toxic metals such as lead, arsenic, and mercury still threaten the local ecosystem.

High concentrations of metals

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Growing threat

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