A recent study led by Ingun Lund Witsø from the Norwegian University of Life Sciences reveals a critical flaw in our wastewater treatment systems: they fail to eliminate several human pathogens that can hide on microplastics in water.
While wastewater treatment plants are designed to effectively remove contaminants, microplastics persist in the environment and become home to harmful microbial biofilms. Previous research has indicated that these biofilm communities, termed plastispheres, may harbor dangerous pathogens that could compromise human health and ecological safety when treated wastewater and sludge are discharged into our water systems.
In this pivotal study, researchers identified food-borne pathogens thriving in plastispheres across three types of plastic found in wastewater. By employing advanced culturing techniques and genetic analysis, the team uncovered a variety of pathogens, including Listeria monocytogenes, Escherichia coli, norovirus, and adenovirus.
They were also able to cultivate Klebsiella pneumoniae and Acinetobacter spp. from both raw and treated wastewater, suggesting that biofilms on microplastics likely shield these pathogens from effective wastewater treatment. These results underscore the possibility of plastispheres to both harbor and disseminate pathogens, presenting a challenge for the safe reuse of wastewater.
In the absence of effective wastewater treatment and management of plastic waste, wastewater may serve as a medium for transferring pathogens associated with plastics into the food chain. The researchers point out that ongoing research and innovation are crucial for the removal of microplastics—and their associated pathogens—from wastewater.
The authors emphasize: “In wastewater treatment plants, plastics are coated with microbial biofilms known as “plastispheres,” which can host harmful pathogens, including Listeria, E. coli, Klebsiella pneumoniae, and Acinetobacter spp. These pathogens can survive the treatment process. This study underscores the alarming potential of plastispheres to facilitate the transmission of pathogens from treated wastewater, presenting significant challenges for environmental health and efforts to reuse water safely.”
Journal reference:
- Ingun Lund Witsø, Adelle Basson, Marina Aspholm, Yngvild Wasteson, Mette Myrmel. Wastewater-associated plastispheres: A hidden habitat for microbial pathogens? PLOS ONE, 2024; DOI: 10.1371/journal.pone.0312157
