After collecting microplastic debris from Singapore’s coastline in the period from April to July 2018, marine scientists from the National University of Singapore have discovered more than 400 types of toxic bacteria on these microplastics that can cause coral bleaching and infections on wounds in humans.
The scientists from the NUS Tropical Marine Science Institute, led by lead researcher Dr Sandric Leong, and Ms Emily Curren, a PhD at the Institute, discovered the Photobacterium rosenbergii bacteria on the microplastic debris after utilising DNA sequencing to analyse the samples. This type of bacteria is known to cause coral bleaching and disease. The team also discovered Vibrio, a marine bacteria that can cause wound infections in humans, and Arcobacter, a bacteria that can cause gastroenteritis, on the microplastic debris collected.
According to Ms Curren, the fact that the microplastic debris were collected in public recreational areas that were easily accessible reinforced the added importance of identifying the “potentially pathogenic bacteria” as this could be be an important step in “preventing the spread of diseases” in Singapore.
Microplastics, which are broken down from single-use plastic items such as plastic cutlery, straws and crockery disposed in the ocean, have a lifespan of hundreds of years and can be used by toxic bacteria as “safe havens” to propagate and thrive. Through time, these microplastic debris contaminated by harmful pathogens are eaten by small marine organisms like barnacles, which are in turn eaten by fishes – thus spreading harmful diseases to us by making their way up the food chain to humans.
With plastic pollution a major environmental problem and microplastics making up a large proportion of plastics in the ocean, the consumption of microplastics by marine organisms can lead to an accumulation and transference of marine pathogens up the food chain to human populations around the world.
Dr Leong cautioned that the analysis of the distribution of microplastics and the identification of the marine organisms associated with them are important steps to managing the problem of plastic pollution “on a national and global scale.