The Seattle PI has a blog post called "Why I Love Biosolids." I'm including excerpts below, with my own commentary.
In the last few weeks several people have come to me asking about the safety of biosolids-use in their home gardens, and moreover, have asked why I advocate the use of biosolids. In short, biosolids composts are safe, highly-regulated, sustainable, climate-friendly products, that your plants will LOVE. They are high in nutrients, support healthy soil microbial communities, and improve the tilth (physical attributes) of soil. Farmers around the world, including US farmers, have known this for ages.
Wow. Where do I start? Safe, no. Highly-regulated, NO. Healthy soil microbial communities? OK, "biosolids" (sewage sludge - let's call it what it is) can contain antibiotic-resistant bacteria and parasites... you call that healthy? |
Biosolids are a product from the wastewater treatment process, and are EPA-regulated under the Clean Water Act.
Just because sewage sludge is regulated by the EPA, that doesn't make it safe. Unfortunately, on this particular issue, the EPA is one of the bad guys. Their standards are incredibly lax - they only regulate 10 harmful substances out of the THOUSANDS you can find in the sewage sludge that they allow farmers and gardeners to use as fertilizer (what they call biosolids - a term that my spellcheck thinks isn't a word, probably because it was made up only to "sell" sewage sludge as a "safe" fertilizer to unsuspecting Americans).
In US cities, everything we flush, throw down the kitchen sink, and wash down the bathroom shower ends up at the wastewater treatment plant. Some people call biosolids sewage sludge, but the term biosolids specifically refers to treated sewage sludge.
That's only a partial description of its contents. It includes everything industry and hospitals wash down their drains too, including heavy metals, dioxins, pesticides, PCBs, you name it.
Here our wastewater gets cleaned via a system of filters, and the solids are left behind. While the clean water is either being used for irrigation as "reclaimed water", or sent into our rivers, lakes, or oceans, the solids go under treatment... What is eventually left at the end of this process, is no longer the original solids, but mostly the dead (and some live) bodies of the microorganisms who consumed our waste.
So here's what happens to all of the toxins that go down the drain... some stay in the water even after it's treated, some go into the air, some are actually removed via composting, and the rest remains in the sewage sludge after treatment.
Before biosolids can be applied to farm land, or distributed to the public for home garden use, they must be vigorously tested, and meet stringent safety regulations. I take comfort in knowing that biosolids are heavily regulated. They are far more heavily regulated than manures, yard waste composts, and fertilizers.
Yeah, soooo... none of that's true.
What about pharmaceuticals and other trace organics?
Pharmaceuticals and other organic compounds are not regulated in biosolids. This does not mean, however, that this topic has not been researched! When EPA set the guidelines for biosolids regulation, they decided not to regulate substances like PCB's, dioxin, and estrogenic compounds, because concentrations are so incredibly low, that they are rarely found. When these compounds are detected, they are in such low concentrations that risk assessment studies (conducted independently by EPA and several U.S. Universities) find risks to the public and environment to be negligible. Despite the fact that these substances are not federally regulated, public works agencies such as King County biosolids division, routinely monitors for these substances... just to be sure. What are the chances fertilizer producers check, just to be sure?
The fact that substances like dioxin, PCB's, and estrogenic compounds exist in the environment is bad, the fact that they are in background level concentrations in biosolids is good. The fact that government agencies and universities continue to monitor and study these compounds is also good.
I've seen the EPA's own numbers from the last time they tested the sewage sludge from 80 sites around the U.S. They found a whole lot of heavy metals, flame retardants, and more in the samples. As for safety, people and animals have died from using sludge as fertilizer. So, quite frankly, I think that's a good indication that there are toxins in sludge at significant levels. And I extend my sympathy to the author of the "Why I Love Biosolids" article because she has been duped into putting her health at risk by using sludge as fertilizer in her garden. |
