New study finds microplastics in human waste as ‘hubs’ for bacteria

Researchers from the New Jersey Institute of Technology (NJIT) have discovered that certain microplastic particles, less than five millimeters in length, have contributed to the possibility of the formation of biofilm, a slimy layer that could lead to the intermingling of both ‘antibiotic’ waste and bacteria. Published in the Journal of Hazardous Materials Letters, these results demonstrated how certain strains of bacteria have elevated antibiotic resistance by up to 30 times when living on microplastic biofilms that form inside sludge units at municipal wastewater treatment plants.

Co-author Mengyan Li notes that extensive research had already been done on the negative impacts microplastic have on ocean and freshwater environments, but till now the role of these plastics in our towns and cities’ wastewater treatment systems remains largely under-looked. According to Li, “These wastewater treatment plants can be hotspots where various chemicals, antibiotic-resistant bacteria and pathogens converge and what our study shows is that microplastics can serve as their carriers, posing imminent risks to aquatic biota and human health if they bypass the water treatment process.”

In the study, scientists assessed three domestic domestic wastewater treatment plants in New Jersey, US, inoculating the samples in the lab with two widespread commercial microplastics — polyethylene and polystyrene. Meanwhile, they tracked genetic changes and identified specific bacteria that grows on the way. What they found was that three particular genes, sul1, sul2, and intI1 – are responsible for the amplification of antibiotic resistance.

Dung Ngoc Pham, another co-author of the study from NJIT has also found these microplastics are able to multiply on their own accord. Of eight different respiratory-causing bacteria grown on microplastics, two pathogens have been found to be linked with respiratory illness. What happens is that when they enter the system, they intermingle with the sludge and attach itself to the surface, secreting glue-like substances. Further studies will be needed to determine how these pathogen-carrying microplastics may be bypassing the water treatment system.

Source: The Economic Times