DC Water is marketing its EPA-certified “Exceptional Quality” Class A Biosolids as a retail soil additive called Bloom. Biosolids are merely the sludge that comes out of a wastewater treatment plant. DC Water is not the first wastewater utility or DC area utility to turn its wastewater biosolids into a soil additive for home gardeners and crops for human consumption. The question is, should we use it.
Bloom typically contains PFOA and PFOS at levels
around 3.68 ppb and 15.5 ppb, respectively. Though Blue Plaines argues
that levels are reportedly thousands of times lower than in food packaging and
even lower than household dust, While PFOA and PFOS have been largely
phased out of U.S. manufacturing for over a decade. It is true that they are
still frequently found in household products and the dust they create comes
from legacy items and imported goods.
Because these are "forever chemicals," they do not
break down. Items purchased years ago continue to shed PFOA and PFOS into your
home environment today. Older stain-resistant carpets are the single
largest source of PFOA and PFOS in house dust. As the fibers wear down, they
release micro-particles that settle on floors. Upholstered furniture treated
with legacy stain-repellents continue to off-gas and shed these specific
chemicals as the fabric ages.
U.S. companies have moved to "short-chain"
replacements (like GenX or PFBS), many international manufacturers still use
PFOA and PFOS in their processes. Buy American. Another problem area is after-market
waterproofing sprays or "stain-guard" products, especially those sold
via online marketplaces from international sellers, may still utilize legacy
PFAS formulas.
Despite the phase-outs, environmental testing as of 2026 continues to show that PFOA and PFOS remain the most common PFAS found in indoor dust. In recent studies, PFOA was detected in 97% of house dust samples, often at the highest median concentrations compared to newer replacement chemicals. PFOA and PFOS levels in household dust have generally declined following their phase-out from U.S. manufacturing, they are still detected in nearly all homes. Modern concentrations typically range from 1 ppb to 50 ppb (parts per billion). According to the U.S. Environmental Protection Agency (EPA) Residents who have lived in their homes longer or clean less frequently are the homes that tend to have higher accumulated levels of PFOA and PFOS in their dust.
A recent study does demonstrate
a link between PFOA and PFOS and infant mortality. The study by Baluja, R. et
al. at the University of Arizona was done in 2025 and titled PFAS-contaminated
drinking water harms infants, found that mothers whose drinking
water came from wells downstream of PFAS-contaminated sites had
a 191% higher first-year infant mortality rate. The study
highlights the danger of direct ingestion of contaminated
water, which resulted in 611 additional infant deaths per 100,000 births. These
sites were contaminated by industrial sources, landfills, or firefighting
activities—sources often associated with much higher PFAS concentrations than
typical municipal biosolids.
Bloom meets Maryland’s most restrictive limit of 20
ppb for PFOA or PFOS, allowing for unrestricted use. Research from
the University of Arizona (the same institution as the Baluja
study) suggests that PFAS in municipal biosolids like Bloom does not
significantly move through the soil into groundwater. Regulators consider the
risks associated with Bloom soil amendment as low due to the concentrations and
exposure pathways involved.
Using a biosolid like Bloom does create a localized exposure
point for chemicals that the federal government is otherwise trying to
eliminate from the consumer cycle. The FDA's recent action eliminates what was
once a "primary source of dietary exposure" (e.g., fast-food
wrappers, microwave popcorn bags). By using biosolids, you are essentially
importing these legacy chemicals back into your immediate living environment.
PFOA and PFOS are "forever chemicals" that do not
break down. Once added to your garden, they remain in the soil and can be taken
up by leafy greens and fruit vegetables, which research shows have
higher bioaccumulation rates compared to root vegetables.
Also, children playing in gardens are at higher risk of "incidental ingestion" of soil and dust. While the concentrations in Bloom are low, they represent an avoidable addition of toxins that are no longer present in your take-out containers, non-stick cooking pans, new furniture and carpeting. The risks specifically associated with Bloom soil amendment are generally considered low due to the concentrations and exposure pathways involved, but we are trying to eliminate these specific chemicals from our homes and bodies. I see no reason to add extremely low concentrations to my life.
If we look at the numbers we've discussed for PFOA in Bloom is about ~3.68 ppb (ppb) and in
average household dust is around ~8.6 ppb (ppb). This means, based on
median samples, household dust can actually have a higher
concentration of PFOA than the Bloom soil amendment. However, a child
playing in a garden might ingest or inhale far more dirt/dust than they would
from a clean indoor floor. In this I am very risk adverse.
DC Water hosted a very informative Webinar last year that you might want to watch to help you make the decision that is right for you.



