LECA Trash on Portugal’s Coast: A Hidden Problem

A recent study reveals that lightweight expanded clay aggregates (LECA)—a ubiquitous building material—are now littering Portugal’s coastlines.

Researchers surveyed eight distinct shoreline sites around Aveiro, ranging from open ocean dunes to sheltered lagoon edges and a bustling port channel. In each 50‑meter stretch, they catalogued tiny sponge‑like LECA fragments, finding counts that spanned from just a handful to more than 2,000 per 50 meters.

The largest concentrations were near the lagoon’s mouth, suggesting that cargo ships and loading docks may be a primary source. Additionally, water currents could be transporting debris from the port into adjacent waters, dispersing it beyond its initial release point.

Key findings:

• Density: 0.53–0.67 g/cm³, matching commercial LECA sizes.
• Origin uncertainty: Fragments might be pre‑broken or have disintegrated at sea.
• Environmental risk: LECA is non‑biodegradable, posing long‑term threats to marine life and waterway integrity.

The authors urge further research to trace the debris’s origins, track its movement, and assess its ecological impact on coastal ecosystems.