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Fertilizers could contain more microplastics than previously assumed, according to a new UCLA study

biosolid fertilizer processing

The biosolid byproducts of wastewater treatment serve as lower-cost alternatives to traditional fertilizers, making them popular for use in agriculture. A new UCLA study, co-authored by Eric Hoek (UCLA Civil and Environmental Engineering and director of the UCLA Sustainable LA Grand Challenge) and Sanjay Mohanty (UCLA Civil and Environmental Engineering, UCLA Institute of the Environment and Sustainability), shows that the microplastic content of these biosolids could be higher than originally anticipated. This could have serious implications for public health and pollution control.

Plastic enters wastewater from daily activities, including washing hands and laundering clothes. They then accumulate in biosolids as treatment facilities filter out particles and pollutants from the wastewater. The microplastic content of biosolids previously went undetected because, while microplastics can be caught when entering wastewater treatment plants, they cannot be detected after treatment. This flaw raises concerns because pollutants can stick to microplastics. Toxins can then be transferred into our food or dispersed into the environment.

“This is an important discovery because it points out what we don’t know about microplastics in wastewater biosolids and the possible associated risks of using biosolids to grow our food,” Hoek noted

Learn more about the study and its implications at UCLA Newsroom.

Study Authors

Vera S. Koutnik, UCLA, Department of Civil and Environmental Engineering

Sarah Alkidim, UCLA, Department of Civil and Environmental Engineering

Jamie Leonard, UCLA, Department of Civil and Environmental Engineering

Francesca DePrima, UCLA, Department of Civil and Environmental Engineering

Shangqing Cao, UCLA, Department of Civil and Environmental Engineering

Eric M. V. Hoek, UCLA, Department of Civil and Environmental Engineering; UCLA California NanoSystems Institute; UCLA Institute of the Environment and Sustainability

Sanjay K. Mohanty, UCLA, Department of Civil and Environmental Engineering; UCLA Institute of the Environment and Sustainability