Microbes from sewage sludge used as recycled fertilizer likely enable toxic
“forever chemicals” known as PFAS to leach into the environment, according
to new research led by
Christopher
Sales, PhD, associate professor of civil, architectural and
environmental engineering and doctoral student Asa Lewis. Their study,
published in Environmental Science Processes & Impacts, showed how PFAS
can spread from fertilizer made with microbial decomposition of biosolids.
“This work provides evidence that microbial weathering processes can impact
PFAS partitioning and increase leaching potential in biosolids,” said Sales.
The researchers found biosolids with more microbial activity had higher PFAS
partitioning, indicating the microbes’ breakdown of organic compounds helps
PFAS spread as water passes through. Over three months, especially in the
first 10 days, microbial degradation of proteins and lipids increased PFAS
leaching potential from the treated sewage sludge.
The results suggest microbes facilitate PFAS release into soil, crops and
groundwater when biosolid fertilizers are applied to farmland. About half of
U.S. sewage waste is processed into biosolids then fertilizer. The findings
highlight the need to understand PFAS’ environmental pathway to properly
regulate contamination levels. The researchers say more advanced wastewater
treatment is needed to reduce PFAS impacts.