Some recent media reports and community comments have suggested that farm use of Bloom creates a public health risk, and we want to directly address concerns with science-based information. We are committed to full transparency on the topic of PFAS and biosolids, and we are sharing the following information to help all stakeholders make informed conclusions about the use of Bloom.

What are PFAS?

PFAS are a group of more than 3,000 manmade chemicals that are fire, oil, grease, water and stain resistant, and are found in a wide array of consumer and industrial products, including non-stick cookware, food packaging, dental floss, cleaning products, and cosmetics. Exposure to humans can occur through a number of pathways, including ingestion and inhalation.

From the family of compounds known as PFAS, PFOA and PFOS are among the most studied and have the largest data sets to support risk assessment. Measurements of Bloom, DC Water’s EPA designated Exceptional Quality Class A biosolids product, have shown concentrations of PFOA and PFOS within ranges up to 3.68 parts per billion (ppb) and up to 15.5 ppb respectively – many thousands of times lower than in food packaging materials; hundreds of times lower than in products like ketchup, organic tomato sauce, and cosmetics; and ten times lower than the levels measured in dust. Bloom’s total combined PFAS levels average 130 ppb, which is more than 2,000 times lower than the food packaging limits set in California, one of the few states to restrict the compounds.

Poolesville WellsPFAS Comparisons for Different Sources

Recently, the town of Poolesville in Montgomery County, Maryland decided to shut down two of its local wells due to elevated PFAS levels.

There are many potential sources of PFAS that could have led to the contamination, and no evidence that biosolids generally or Bloom specifically contributed to the contamination of the wells. Bloom is an exceptional quality Class A product approved for sale and use.

DC Water began distributing Bloom in the DC metro area in 2016 to provide customers in the area the benefits of this locally sourced fertilizer and soil amendment. DC Water’s Bloom product is permitted for use in DC, Maryland, Pennsylvania and Virginia. DC Water has sold Bloom to farmers and other users in Montgomery County and elsewhere since then. Last year almost 57,000 tons of Bloom was sold, and about 3,000 tons of Bloom a year has been applied
near Poolesville.

When contacted DC Water looked at the Water Supply Evaluation for the Town of Poolesville, Maryland completed by S.S. Papadopulos and Associates in 2021. Figures 23-26 in that report illustrates that the recharge areas for the Town’s wells generally fall within the Town limits. A recharge area is the place where water is able to seep into the ground and refill a well. The Source Water Assessment for the Town of Poolesville Public Water System by VIEW
Engineering in 2006 reached a similar conclusion about well recharge areas.

No Bloom customers fall within the well recharge areas, and in some cases there are other wells with no PFAS detections between Bloom customers and the wells in question. The Source Water Assessment showed that the general direction of groundwater movement is from north to south toward the Potomac River, so groundwater from this site is expected to move away from the Town. Bloom customers are mainly to the west of town.

PFAS has been in the environment worldwide for decades, and the sources of PFAS in groundwater are ubiquitous, including surface water, rainfall, air emissions, and many other discharges to soil and water. The science on PFAS shows that risks from biosolids are minimal and are far outweighed by the benefits of returning the vital nutrients in wastewater solids to the soil through biosolids. For more information on PFAS and Bloom, please read our factsheet.

1 PFAS in the US population, ATSDR (
2 Concentrations of perfluoroalkyl substances in foods and the dietary exposure among Taiwan general population and pregnant women, ScienceDirect
3 Per- and polyfluoroalkyl substances in paired dust and carpets from childcare centers, PubMed (
4 Fluorinated Compounds in North American Cosmetics, Environmental Science & Technology Letters (
5 Toxic PFAS, the “Everywhere Chemicals,” Are in Organic Pasta Sauce and Ketchup, Drugs, Pesticides, and Foodware, Sierra Club
6 PFAS in Biosolids: A Southern Arizona Case Study,The University of Arizona, 2020