Should we stop using sewage-based fertilizer because of PFAS?

“Sewage-sludge” fertilizers like Milorganite are being found with high levels of PFAS. These chemicals are already in the sewage, and when processed into fertilizer, they become more concentrated. This leads to soil contamination and PFAS showing up in plants, which eventually makes its way into the food chain. PFAS has been detected in cows that graze on contaminated grass, showing up in their meat and milk.

I think this forum should reconsider recommending sewage-sludge fertilizers.

Sources:

  1. https://archive.is/8rNG6
  2. Archive Buttons | Free Paywall Remover

Extra info:

Study: https://www.sierraclub.org/sludge-garden-toxic-pfas-home-fertilizers-made-sewage-sludge

Milorganite specifically had 0.67 parts per billion of PFOA (below the 2.5ppb limit) and 8.66 parts per billion of PFOS (above the 5.2ppb limit).

The study advises against using any sewage-sludge fertilizers, and they tested 9 different ones.

The 2024 Lawn of the Year contest is happening! You have until September 30th to submit your lawn. Submit your entry here. Show off what you’re proud of!

This is an automated post. Please reach out to the mods if you have any questions.

I’m curious, what exactly is the harm of using this on a lawn? Does it hurt wildlife? Could it get into the water we drink? And what would happen to this sewage if we didn’t turn it into fertilizer?

I agree with you, I wouldn’t want to use this stuff on food crops, but for lawns, I’m not so sure. I’m open to hearing more though.

@Noe
The problem is that PFAS takes forever to break down, so it stays in the soil for decades. Some of it could seep into the groundwater, and plants can absorb it too. This means it could end up in leafy greens, and then wildlife eats those plants, spreading it further. Also, someone in the future might want to grow food on that same lawn.

From the article:

“Unknown to them, her family’s farm was fertilized decades ago with sewage sludge contaminated by chemicals linked to cancer, liver disease, and more. Their cows grazed on it, and now the beef and milk are too dangerous to consume.”

Do we know the PFAS content in Milorganite?

Tarian said:
Do we know the PFAS content in Milorganite?

Study: https://www.sierraclub.org/sludge-garden-toxic-pfas-home-fertilizers-made-sewage-sludge

Milorganite had 0.67 parts per billion of PFOA (below the 2.5ppb limit) and 8.66 parts per billion of PFOS (above the 5.2ppb limit).

The study advises against using any sewage-based fertilizers, and they tested 9 different ones.

@Maris
Thanks, that’s helpful.

Is there data on non-sewage fertilizers and their PFAS content?

The numbers don’t back your claim.

To reach harmful levels, you’d have to eat Milorganite regularly.

https://ofmpub.epa.gov/eims/eimscomm.getfile?p_download_id=542402

At 62g per square meter, with a 38 pbb concentration, it’s so diluted that one heavy rain will wash it away, and rainwater might have more PFAS anyway.

Think of it like adding one match to a fire of 1000 logs—it doesn’t make a difference.

So saying, “every bit counts” is like saying turning off the faucet will save the Titanic. The difference is huge.

I’m sticking with Milorganite, but thanks for bringing this up.

Bad news for you: https://www.dailymail.co.uk/sciencetech/article-11073139/Rainwater-locations-Earth-contains-unsafe-levels-forever-chemicals-linked-cancer.html

It’s in the rain now, so try not to worry too much.

@Darby
Just because it’s everywhere doesn’t mean we should ignore it. Your comment is like saying, “There are wildfires everywhere, so it’s fine to toss embers on dry grass.”

We should still do what we can to make things better.

I agree. We should discourage using Milorganite here, and the mods and any experts should also back that up.

Cairo said:
I agree. We should discourage using Milorganite here, and the mods and any experts should also back that up.

Sorry, I’m new to this. I’ve been following this guide: A Beginner’s Guide to Improving Your Lawn and it suggests Milorganite:

https://www.homedepot.com/p/Milorganite-32-lb-2-500-sq-ft-Organic-Slow-Release-Nitrogen-Lawn-and-Garden-Dry-Lawn-Fertilizer-6-4-0-100539618/308888983

Should I avoid buying it?

@Haven
Yes, I’d suggest finding a different fertilizer. That guide is a bit outdated.

Thanks for posting this. I’d love to see more discussions like this.

Never used Milorganite myself, always thought there were better options. I’ll check out those articles.