The Toxic Afterlife of a Boat Paint Biocide Is Rewriting Risk Assessment

Irgarol 1051, a biocide used on ship hulls to stop algae, barnacles and slime, is under renewed scrutiny for how it harms environments long after it’s applied. After tributyltin was banned for its effects on marine mollusks, Irgarol became a “safer” replacement by selectively blocking photosystem II in algae. But a review led by Sunday Amos Onikanni at the Federal University of Rio de Janeiro, published in Environmental Science and Pollution Research, argues that today’s risk assessments are outdated. Toxicity can’t be inferred from concentration alone because Irgarol persists, transforms, redistributes and interacts biologically, potentially extending exposure even to humans via seafood.