Microplastics, now ubiquitous in our environment, pose a serious threat according to new research. Those in sewage harbor bacteria with growing antibiotic resistance, as discovered by researchers at the New Jersey Institute of Technology.
Originating from plastic waste, clothing, and cosmetics, microplastics measure less than 5 mm. They contaminate oceans, rivers, polar regions, and even mountaintops, endangering ecosystems and human health. In August 2020, microplastics (and nanoplastics) were first detected in human tissues. Annually, individuals ingest up to 2,000 microplastic particles weekly—equivalent to the weight of a credit card (5 g).
A New Jersey Institute of Technology team examined microplastics during the wastewater treatment process. Their findings, forthcoming in the Journal of Hazardous Materials Letters and highlighted in a March 17, 2021 press release, reveal critical insights.
Lead author Dung Ngoc Pham notes that most wastewater treatment plants fail to remove microplastics. These facilities concentrate microplastics alongside chemicals and pathogens. Alarmingly, microplastics serve as prime breeding sites for microbes.
Researchers analyzed sludge samples from three New Jersey wastewater treatment plants, adding common microplastics like polyethylene (PE) and polystyrene (PS). Advanced techniques, including PCR genetic analysis, tracked bacterial growth and genetic changes on these particles.
They detected sul1, sul2, and intl1 genes—key to antibiotic resistance—at levels up to 30 times higher in microplastic biofilms compared to sand biofilms. Adding antibiotics triggered a 4.5-fold surge in these genes.
In treatment plants, microplastics mingle with sludge, attracting bacteria that form glue-like biofilms. Bacteria exchange DNA, rapidly disseminating antibiotic resistance genes.
The team is now investigating how these bacteria-laden microplastics evade treatment processes.
