How long does LEGO last in the ocean?28
Most research and interventions on marine plastic pollution focus on the plastic that floats at or near the surface. But what about the denser items that sink to the bottom?
Surprisingly, LEGO is one of the items often found piling up on the seabed. It can get caught up in fishing nets or washed up on the shore after storms, which is how a team of researchers in the UK ended up studying it.
In a paper in Environmental Pollution, Dr. Andrew Turner and colleagues at the University of Plymouth analyze LEGO bricks from the ocean. Dr. Turner found that one of the major routes by which toys are lost is flushing – it is estimated that millions of toys are lost this way every year.
The analysis found that, compared with floating plastic items, LEGO pieces showed less degradation. This is because plastic degrades by exposure to sunlight as well as mechanical abrasion. The plastic that lasts longer tends to be the denser plastic that sinks to the seabed, away from sunlight.
The survival time the team estimated in their paper was 100–1,300 years. The uncertainty in the estimate is a result of the different conditions the LEGO bricks are subjected to in the ocean.