By Sally Brown, University of Washington

Forget climate change. Forget soil degradation. Forget water quality. Biosolids can help all of those - better than most other tools we have. The real threat - if you read the Boston Globe - are forever chemicals and the place where you find those is biosolids. The Globe recently published an article about ‘forever chemicals’ aka PFAS, PFOA and associated compounds in biosolids. 

The author of the article clearly had an agenda and that agenda more than colored the perspective of the piece. The Globe is a well-respected paper and this topic has traction. As a community we need to speak directly to show the fallacies with this agenda. It is time to get grounded in the reality of PFAS and biosolids so that you can stand strong and on science when the next reporter with an agenda comes asking you questions.  

First point - the article reported concentrations of 3 PFAS chemicals in the Boston biosolids as 18,000 parts per trillion. That is a deliberate way to incite fear. People read 18,000 and have no clue what parts per trillion is. A few points to bring the real number home.ruler

18,000 ppt is the same as 18 ppb or 0.015 ppm or about 0.04 inch of the length of the US from sea to shining sea or about 1 second in 570 years.  Talk about the blink of an eye. Or about 0.02 person per the 327 million people who live in the US.  Think of a finger.


Or a really irresponsible and deliberately misleading way to report a concentration.  

The article then talked about the famous farm in Maine (see below). The farm had used biosolids and pulp sludge at high rates in the 1980s and 1990s- before industries started phasing out the use of PFAS and PFOA. The cows on the farm had milk that contained 1 420 ppt of PFAS and the owners of the farm had 20x the normal amount of PFAS in their blood.  Those levels were 111 ppb for Mr. Stone and then 93 ppb for his wife. The article I saw specifically said ‘PFAS’ in the blood but was from a local newspaper and not a journal. It is not clear if this was the sum of PFAS and related compounds or just PFAS.   

Maine pfas

Let’s talk about the blood concentrations.  The article where I found the blood concentrations - Bangor Daily News - says that the average American has average blood PFAS concentrations of 4.7 ppb.  If you write for the Globe you would say 4,700 parts per trillion.  Put that number in perspective of what blood levels across the US have been across time. Look at the data from the graphs below (Olsen et al., 2017).  Back in 2000- pretty much everybody had screaming high concentrations of these compounds in their blood. Summing across the three compounds reported- the blood concentrations in men were over 40 ppb for men - lower than the levels found in Mr. Stone’s blood but far from compound free.  In Boston Globe units that is 40,000 ppt or more than double the concentration in the biosolids.  THAT IS THE BIG STORY.

pfos blood levelsPFHxS and PFOA concentrations

The reason that blood concentrations were so high was because compounds were ubiquitous in a wide range of household products (see the June 2019 Biobull for a concentrations quiz).
That is how they got into blood.  Banning the largest chain compounds has worked.  Blood concentrations are going down.  But a broader range of similar but smaller compounds has taken their place.  Because those shorter chain compounds are also found in a broad range of every day products, they will also be found in our blood.

In order for biosolids to be the disease rather than just a symptom- there would need to be a way for the perfluorinated compounds detected in the biosolids to get into people.  If you go back to the Maine farmers- the article suggests that drinking the water from the well on the farm and the milk from the cows was how the couple were exposed.  It is highly likely that all of the milk that they drank and the vast majority of the water they drank came from their own land.  For biosolids to be the ‘cause’ of the problem there would need to be a similar pathway for the people in the US who have detectable concentrations of PFAS and related compounds in their blood.  There just isn’t that much treated poop.  Remember that we make enough biosolids to apply to about 0.1-1% of all arable land each year.  That is not a lot.   

A recent study looked at likely sources of PFAS in women’s blood in California (Boronow et al., 2019- June library).  They found that eating takeout- particularly foods wrapped in paper rather than stored in cardboard, and using dental floss were significant factors.  So was having stain resistant furniture and carpets in your home.  Tainted water supplies were also a factor.  Here realize that biosolids do not impact municipal water supplies.  Fire-fighting foams and other point source large scale uses of high PFAS containing products do.  What this tells us is that people and their homes are the cause of the concentrations in the biosolids.  In a few standout cases- like Decatur, AL, industrial discharges can elevate concentrations in the municipal wastewater system.  Those are point sources and easy to stop.  That we should do.  But for most cases- cleaning up the biosolids means getting rid of the people.  No one would argue that that is a viable solution.  

So- your talking points here.  Biosolids are the symptom of a much larger problem.  Getting rid of the biosolids will just cause many more- much bigger problems.  On the big picture scale biosolids are the answer, not the problem.  Put those units into perspective.  Put the source into perspective.  Do not argue that PFAS are great things.  Argue that if PFAS are problematic let’s stop using them in EVERYTHING.  If we get them out of our homes and our food- we will also get them out of our biosolids.  

Many associations and agencies have very helpful fact sheets on these compounds.  Ned Beecher at NEBRA has been the national lead.  Greg Kester from CASA provided this link:

Boronow, K.E., J. Green Brody, L.A. Schaider et al. 2019.  Serum concentrations of PFASs and exposure-related behaviors in African American and non-Hispanic white women.  J. Exposure Sci. & Environ. Epidemiology 29:206-217.

Olsen, G.W., D.C. Mair, C.C. Lange et al.  2017.  Per- and polyfluoroalkyl substances (PFAS) in American Red Cross adult blood donors, 2000–2015☆.  Environ. Research 157:87-95.