Johns Hopkins: Toxic Chemicals in Biosolid Fertilizers

A recent study by Johns Hopkins University reveals the presence of hazardous chemicals in biosolid fertilizers, highlighting 92 compounds that might pose health risks. This research underscores the necessity for comprehensive risk assessments and improved regulations to safeguard public health.

Biosolid Fertilizers and Potential Risks

Fertilizers produced from the residual sludge of wastewater treatment processes, known as biosolids, contain traces of potentially hazardous organic chemicals. The study, published in the Environmental Science & Technology journal, offers an extensive analysis of the chemical composition of biosolids across the United States and marks the initial step towards identifying common chemical contaminants that may require government regulation. These findings could assist the U.S. Environmental Protection Agency (EPA) in prioritizing which organic compounds to investigate further.

Assistant professor Carsten Prasse from the Department of Environmental Health and Engineering emphasized the importance of understanding the organic hazards in biosolids. “Regulators need to know what these types of fertilizers are made of to determine how they can be responsibly used,” Prasse stated. His team employed analytical chemistry techniques to identify thousands of chemicals in 16 biosolid samples from wastewater treatment facilities in nine U.S. and three Canadian cities. The samples revealed traces of pharmaceuticals, industrial chemicals, and various fragrances, including bisphenol A (BPA) and carbamazepine.

Chemical Analysis and Regulatory Considerations

The researchers aimed to identify chemicals that are widespread and potentially problematic, warranting further investigation by the EPA. By creating lists of chemicals found in each sample and comparing them across different locations, the team identified 92 compounds present in 80% or more of the samples. These compounds were then cross-referenced with the EPA’s CompTox Chemical Dashboard to assess their properties, hazards, and potential risks.

Matthew Newmeyer, a research associate at the Bloomberg School of Public Health and the study’s first author, clarified that the identified compounds do not pose an immediate risk. “We’re saying that these have a potential to be problematic and we need more information in order to make sure these biosolids are safe,” Newmeyer explained. Despite potential risks, biosolids offer benefits. They are rich in nutrients like nitrogen and phosphorus, require less energy to produce than synthetic fertilizers, and help reduce waste sent to landfills or incinerators.

Future Research Directions and Implications

In 2022, over half of the 3.76 million tons of biosolids produced in the U.S. fertilized agricultural lands, golf courses, and other landscaped areas, according to the EPA. While direct contact with biosolids is limited to certain occupations, the broader population might be exposed to contaminants through crops grown in biosolid-amended soil. The researchers plan to measure the identified compounds in both biosolids and vegetables grown in such soil to determine if concentration levels are concerning. They are also examining risks to farmers, landscapers, and composters who work with biosolids.

This study by Johns Hopkins University highlights the necessity for detailed risk assessments and regulations to ensure the safe use of biosolid fertilizers. While offering significant agricultural benefits, biosolids may also pose potential health risks that warrant further investigation.

Reverse osmosis filtration and whole-home water conditioners can play a vital role in mitigating exposure to contaminants found in biosolids. Reverse osmosis systems effectively remove a wide range of chemicals, including those identified in the study, from drinking water. Whole-home water conditioners can enhance the quality of water used for irrigation, reducing the risk of contaminants being absorbed by crops. Implementing these technologies can help ensure safer agricultural practices and protect public health.

Source: SciTechDaily