Nearly half of the world’s aquatic environments are classified as “dirty” or “extremely dirty” due to contamination from plastic and cigarette butts, according to a study released on Apr. 19. The research, coordinated by Ítalo Braga de Castro and led by doctoral student Victor Vasques Ribeiro at Brazil’s Institute of Marine Science at the Federal University of São Paulo, analyzed a decade’s worth of data from articles published between 2013 and 2023 using the Clean Coast Index.
The findings highlight widespread pollution in global water bodies, raising concerns about environmental health and human safety. Microplastic pollution has been linked to contamination in food and drinking water, which can have serious health effects.
The study found that 46% of aquatic environments worldwide contain significant amounts of trash. Researcher Danilo Freitas Rangel said, “We analyzed 445 protected areas in 52 countries. The conclusion is unequivocal: Protection reduces contamination by up to seven times.” Rangel also noted that “about half of the protected areas investigated were classified as ‘clean’ or ‘very clean.’ Even so, protection is no guarantee of immunity from increasing human pressure. About 31% of protected areas were classified as ‘dirty’ or ‘extremely dirty,’ showing that they aren’t effectively immune to contamination by litter in the sea.”
Researchers observed that within protected zones, cleaner areas tend to be located at their centers while dirtier sections are more common along edges.
The study provides valuable information for researchers and policymakers seeking effective strategies for protecting water sources. It also suggests that while protections can help reduce littering impacts significantly, ongoing efforts are needed to address persistent threats—especially near boundaries where pollution tends to accumulate.
Looking forward, experts say both policy action and individual choices—such as reducing single-use plastics—are important steps toward improving water quality globally.
