A study from Virginia Tech warns that nanoplastics present in drinking water not only contaminate but can also strengthen dangerous bacteria, making their elimination in treatment systems more difficult.
Published in the journal Water Research and led by researcher Jingqiu Liao, the work reveals that these tiny particles can interact with environmental microbes and increase indirect risks to human health.
How nanoplastics act
Nanoplastics, which range in size from 1 to 1,000 nanometers, can:
- Strengthen bacterial biofilms in pipes and water distribution systems.
- Increase resistance to disinfectants, complicating the task of keeping drinking water safe.
- Favor the survival of antimicrobial-resistant pathogens, with direct implications for public health.
“Nanoplastics can make antimicrobial-resistant pathogens survive better, which could be detrimental to the environment and have implications for public health,” explained Liao.
Biofilms and resistant bacteria
Biofilms are communities of bacteria that adhere to surfaces and produce a protective material. Although they are not always harmful, in drinking water systems they can harbor dangerous bacteria such as E. coli and Pseudomonas aeruginosa.
The study showed that when exposed to nanoplastics:
- The bacteria communicated with each other and released substances that made the biofilm thicker and more resistant.
- Prophages (viruses inserted in bacterial genomes) were activated, generating new viral particles.
- The bacteria used defense systems like CRISPR to resist phage attacks.
Implications for water treatment
The increased mechanical resistance of biofilms poses a challenge for water treatment and distribution systems:
- Greater difficulty of removal on pipe and plant surfaces.
- Risk of persistent biofilms that compromise the quality of drinking water.
- Need for new disinfection strategies adapted to the presence of nanoplastics.
Future research
Liao emphasized the importance of additional studies to understand the molecular processes behind these interactions. She also highlighted that particle size is key: microplastics, larger than nanoplastics, could affect the relationships between bacteria and phages differently.
The findings from Virginia Tech provide a new perspective on the interaction between nanoplastics, bacteria, and viruses in drinking water systems. The risk is not limited to plastic contamination but extends to the fortification of dangerous bacteria, posing a challenge for public health and environmental management.
