LECA Trash on Portugal’s Coast: A Hidden Problem

A new study shows that lightweight expanded clay aggregates, a common building material, are flooding Portugal’s beaches. Researchers walked along 50‑meter stretches of shore at eight different spots around Aveiro, from open ocean dunes to sheltered lagoon edges and a busy port channel. At every site they found some of the tiny, sponge‑like LECA pieces, with numbers that ranged from only a handful to over two thousand per 50 meters. The biggest piles appeared near the lagoon’s mouth, hinting that cargo ships and their loading docks might be a major source. Water currents could also be pushing the debris from the port into nearby waters, spreading it farther than the original release point.The clumps were light (about 0. 53 to 0. 67 grams per cubic centimetre) and matched the size of LECA sold by local companies, so they were likely not a new material. However, the researchers could not say for sure whether the fragments had broken apart in the sea or were already small when they left their makers. Because LECA is non‑biodegradable, it may stay in the environment for a long time and could harm marine life or clog waterways. The paper calls for more work to track where the debris comes from, how it moves in water, and what effects it might have on coastal ecosystems.