Scientists Warn: Mar Menor Metal Pollution Exceeds Global Toxicity Limits

Recent research highlights alarming levels of metal pollution in the Mar Menor that exceed global toxicity limits. The study, conducted by the Institute of Environmental Science and Technology and the Department of Physics at the Autonomous University of Barcelona, was published in the Marine Pollution Bulletin.

High Levels of Metal Toxicity in Mar Menor

The findings indicate that sediments in the Mar Menor contain lead, arsenic, zinc, mercury, copper, and silver at concentrations surpassing toxicity limits observed in similar coastal ecosystems worldwide. This situation categorizes the Mar Menor lagoon in Murcia as a critical case of historical coastal pollution.

Sources of Contamination

The primary source of this metal pollution is the mining activities in the Sierra de Cartagena-La Unión region. Intensive mining occurred from the late 19th century until the mid-20th century. Although mining operations ceased in the 1990s, metals continued to leach into the lagoon through runoff from heavy rains.

Historical Context and Evolution

Historical data shows that the highest concentrations of metals were recorded in the mid-20th century. Following a ban on mining waste disposal in 1955, some metal levels decreased. However, urban sources and runoff from historical mining areas have continued to contribute to the problem.

Current Status of Pollution

Today, surface metal levels are lower than those of the 20th century, but significant amounts remain stored in the lagoon’s sediments. These metals pose potential risks, as they can be released under specific environmental conditions.

Impact on Biodiversity

Researcher Irene Alorda cautioned that although current metal levels do not seem to affect living organisms directly, future risks could emerge. Interactions from human activities, climate change, and sediment resuspension may reactivate these contaminants, threatening aquatic biodiversity.

Importance of the Research

The study not only documents the pollution status of the Mar Menor but also provides essential insights for developing conservation and mitigation strategies. It emphasizes the need to consider historical impacts alongside current challenges posed by global change when managing vulnerable coastal ecosystems.

Future Actions Required

• Control historical pollution while addressing new pressures from climate change.
• Implement effective sediment management strategies.

The research serves as a scientific foundation for future conservation plans, applicable not only to the Mar Menor but also to other coastal ecosystems facing historical environmental liabilities.