A recent study reveals that wastewater treatment is ineffective at eliminating certain human pathogens that can hide on microplastics in the water.
A recent investigation led by Ingun Lund Witsø from the Norwegian University of Life Sciences has found that wastewater treatment struggles to eliminate several human pathogens when they are associated with microplastics. This study was published in the open-access journal PLOS ONE on November 6, 2024.
Wastewater treatment facilities aim to eliminate pollutants from wastewater, yet microplastics remain and can be colonized by a sticky layer of microorganisms known as a biofilm. Previous studies have indicated that these microbial communities, referred to as plastispheres, may contain harmful pathogens, which can pose risks to both human health and the environment when treated wastewater and sludge are discharged.
In this latest research, scientists detected food-borne pathogens residing in plastispheres on three different types of plastic found in wastewater. They cultivated these microorganisms and utilized genetic methods to analyze the diversity and composition of the plastisphere communities. The team uncovered the presence of harmful bacteria and viruses, such as Listeria monocytogenes, Escherichia coli, norovirus, and adenovirus. They also managed to grow Klebsiella pneumoniae and Acinetobacter spp. from both raw and treated wastewater, suggesting that the biofilms on microplastics likely shield these pathogens from the treatment processes.
These results underscore the risk associated with plastispheres harboring and transmitting pathogens, presenting significant challenges for the safe reuse of wastewater. Inadequate wastewater treatment and poor plastic waste management may allow wastewater to transport plastic-related pathogens into the food supply. The authors stress the importance of ongoing research and innovation to effectively eliminate microplastics and their associated pathogens from wastewater.
The study’s authors note: “Plastics in wastewater treatment facilities are covered by microbial biofilms, or ‘plastispheres,’ which can contain pathogens such as Listeria, E. coli, Klebsiella pneumoniae, and Acinetobacter spp., that survive treatment processes. This research highlights the potential of plastispheres to facilitate the spread of pathogens from treated wastewater, raising concerns for environmental health and water recycling initiatives.”
