Marine scientists from the National University of Singapore (NUS) have uncovered toxic bacteria living on the surface of microplastics collected from the coastal areas of Singapore – and some of them could result in wound infections and gastroenteritis.
In a statement on Monday (Feb 11), NUS said that from April to July last year, the research team found more than 400 different types of bacteria across 275 pieces of microplastics picked up from three beaches – namely Lazarus Island, Sembawang Beach and Changi Beach.
The team – made up of Dr Sandric Leong, research lead and senior research fellow at the NUS Tropical Marine Science Institute, and Emily Curren, a PhD student at the Institute and the Department of Biological Sciences at the NUS Faculty of Science – found a total of five bacteria species: marine Vibrio, Arcobacter, Photobacterium rosenbergii, Erythrobacter and Pseudomonas veronii.
According to NUS, the first two species on the list are harmful to humans – marine Vibrio is a major cause of wound infections in humans and Arcobacter is known to cause gastroenteritis in humans.
Curren said: “As the microplastics we studied were collected from locations easily accessible to the public and in areas widely used for recreation, the identification of potentially pathogenic bacteria would be important in preventing the spread of diseases.”
NUS said that the another species identified – Photobacterium rosenbergii – is often associated with coral bleaching and disease. If this proliferates and accumulates, it could harm the coral reefs in Singapore, whose “southern strait is characterised by multiple coral communities with great biodiversity that are under conservation”.
Apart from toxic bacteria, the team also identified useful organisms in the plastic waste – namely bacteria species Erythrobacter, which is capable of degrading plastic, and Pseudomonas veronii, which can be used to clean up oil spills.
In response to the discovery of bacteria species Erythrobacter and Pseudomonas veronii on the microplastics, Curren said: “Given the predicted increase in plastic waste contamination in oceans, the discovery of such bacteria provides important nature-friendly alternatives for the mitigation of plastic pollution and toxic pollutants such as hydrocarbons.”
All of these bacteria may be transferred up the food chain – to humans – if they are ingested by marine organisms, NUS said.
Dr Leong said: “Microplastics form a large proportion of plastic pollution in marine environments. Marine organisms may consume bits of microplastics unintentionally, and this could lead to the accumulation and subsequent transfer of marine pathogens in the food chain.”
NUS also said that there are now more than 150 million tons of plastics in the ocean, and because of the presence of salt and a lower temperature, microplastics in aquatic ecosystems take a much longer time to degrade compared to that on land.