Human Sewage Sludge in Compost? It’s Really a Thing (and BEWARE)

If you don’t want to wind up with shampoo chemicals in your garden tomatoes, this information is for you. Now, I get it. When you swing by your local home improvement store for bagged fertilizer for your lawn or garden, the last thing you’re probably thinking about is toxic compounds. But there’s something you need to know. Human sewage sludge in compost is common and often marketed as “organic” despite chemicals sneaking into the mix.

This “sludge” is the biosolid product leftover in wastewater treatment plants. In theory, using human waste as a nitrogen-rich, natural fertilizer seems logical, but it’s not that simple today. Why? Think of all of the things that go down the drain and into wastewater plants: everything from shampoo and antibacterial soap chemicals to medication residues and more. And it’s not just what’s drain-bound from U.S. homes, either. Waste from mortuaries, hospitals, industry and businesses also winds up in wastewater treatment plants and often in the leftover sludge, too.

In fact, elevated concentrations of the antibacterial soap chemical triclosan and even flame retardants find their way into biosolids. (Biosolids is a nicer word for sewage sludge). These harmful compounds find their way into yards, playgrounds, golf courses and farm fields (1)

Human Sewage Sludge in Compost: What Are the Threats?

According to United Sludge-Free Alliance, legal loopholes supported by the Environmental Protection Agency, state environmental protection agencies, the United States Department of Agriculture and the Centers for Disease Control and Prevention helped catapult the sewage sludge industry to become big business. After all, there’s a lot of waste to deal with…it has to go somewhere.

This human sludge used to be dumped at sea but was causing major problem and was banned in the 1990s. Instead, federal, state and local entities decided to market this harmful sludge as “biosolids” and “organic fertilizer” or “compost” to get rid of it in a cheap way.

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The real issue is we need to clean up our nation’s chemical laws so toxic chemicals don’t wind up in wastewater treatment plants that can’t handle them in the first place. But until then, I can’t recommend you using compost or other fertilizers containing human sewage sludge in your garden or anywhere else. And get this: Arizona State University researchers are now turning to human sewage sludge to track the harmful chemicals inside of humans. Knowing this, it’s pretty clear our sludge is in no way safe to use in our gardens, farm fields or beyond. (2)

Here are important dangers of human sewage sludge in compost and fertilizing products:

Industrial Contaminants

Milorganite, a sludge-based product marketed as organic-based nitrogen fertilizer, comes from the Milwaukee Metropolitan Sewerage District. According to Darree Sicher of United Sludge-Free Alliance, some Milorganite human sewage sludge in compost/fertilizer products contain a warning label that reads: “WARNING this product contains detectable quantities of chemicals known to cause cancer, birth defects, or other reproductive harm. This notice in no way implies that we have any evidence or experience to indicate that any genuine hazard of cancer, birth defects, or reproductive harm results from the normal, proper handling described on our label and related literature.”

Milorganite’s also been under fire for high levels of PCB contamination. (PCBs are linked to several types of cancer.) According to a Milwaukee Sentinel report,  the Milwaukee Metropolitan Sewerage District faced toxic sewer conditions that led to tons of Milorganite fertilizer contamination. Thousands of pounds were distributed before routine testing uncovered the contamination. Thirty recreational fields using the “organic” compost were closed until the hazardous topsoil could be removed. The contamination in this case came from leaking storage tanks and hydraulic lines that were oozing into city sewers. (3)

Heavy Metals

Heavy metals, including nanoparticle silver, have been detected in human sewage sludge. (4, 5) If you continuously apply sewage sludge contaminated with heavy metals in your garden, be building up dangerous metals in your soil and food.

As Sicher notes, even the EPA, USDA and the U.S. Food and Drug Administration recognize that heavy metals “translocate” into edible tissue of plants and animals. She says many sludges contain substances that could contaminate certain crops, making them unfit for human consumption. The contaminants of greatest concern are heavy metals, toxic organic compounds and pathogenic microorganisms.

The EPA federal policy recognizes the following edible plants by gauging their metal uptake:

• High uptake — lettuce, spinach, chard, escarole, endive, cress, turnip greens and carrots
• Moderate uptake — kale, collards, beets, turnips, radish, mustard, potatoes, and onion.

Flame Retardants & Personal Care Chemicals

Arizona State University scientists found that 10 of the 11 chemicals found in greatest abundance in treated municipal sludge or biosolids included high-production volume chemicals: flame-retardants, antimicrobials and surfactants. (Surfactants often can be found in detergents, emulsifiers and foaming agents and dispersants found in everything from the fracking industry to shampoos and soaps.) The treated sludge also tested positive for abundant levels of pharmaceutical and personal care products. Also detected? Brominated flame retardants commonly found in plastics, textiles, electronics and couch foam. (6)

In fact, phthalates, hormone-disrupting chemicals found in fragrances used in shampoos, sunscreen, lotion and soaps, are now detected in tomatoes grown in human sewage sludge. (7)

Possible Sewage Sludge Symptoms

Sewage sludge exposure has reportedly caused everything headaches, nausea and vomiting to breathing problems, asthma attacks, skin infections, joint pain, diarrhea and even death. (8, 9)

How to Source Safer Compost & Protect Your Community

Compost is certainly important for home gardens and if properly sources, is much safer than harsh chemical-based products that can sterilize beneficial microorganisms in the soil. Here are a few tips to make sure you’re avoiding human sewage sludge in compost:

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• If your municipality offers free compost, be sure to call the office and find out the source of the compost. Is it just leaves or are biosolids used, too?
• Don’t be tricked by bag labels. There are no labeling requirements for bagged fertilizers. Even if a product contains sewage sludge or biosolids as an ingredient, it can still be marketed as “compost” without disclosing the sludge. Sludge can legally be blended into other bagged fertilizers with no labeling requirement.
•  Human sewage sludge in compost can be marketed using words like: “organic,” “sterilized,” “pasteurized” or “sanitized.”
• Consider making your own compost. Here’s how.
• If you want to purchase bagged compost/fertilizer, call the 1-800 number on the package and ask what is used to create the product. Avoid anything with biosolids/municipal waste.
• Urge your local officials to stop using sludge/biosolids on your parks, playgrounds, schools and athletic fields. Tell your state and federal elected officials a change to the laws to keep human sewage sludge in compost out of food, water and communities.

Products Linked to Human Sewage Sludge Ingredients

According to United Sludge-Free Alliance, here are some (but likely not all) products containing human sewage sludge:

• All‐Gro (Synagro)
• Agresoil (NJ)Amend (Kellog)
• Bay State Fertilizer (Boston, MA)
• Chesapeake Sunshine
• ComPro (Washington, D.C.)
• Dillo Dirt (Austin, TX)
• Earthlife (New England Organics)
• Earthmate (Philadelphia PA)
• EKO compost
• Glacier Gold (Olney, MT)
• Granulite (Synagro)
• GroCo (Seattle, WA)
• Gromulch (Kellog product)
• Hou‐Actinite (Houston, TX)
• Landscapers’ Advantage (PA)
• Meadow Life (New Jersey)
• MetroGro (Madison, WI)
• Milorganite (Milwaukee, WI)
• N‐Viro BioBlend
• N‐Viro Soil
• Nitrohumus (Kellog)
• Nutri‐Blend Inc. (Richmond VA)
• Nutri‐Green (Virginia Beach, VA)
• ORGRO (Baltimore, MD, marketed by Veolia Water North America)
• OCEANGRO (NJ)
• SilviGrow (Seattle, WA)
• SkyRocket (Comox, BC, Canada)
• SoilPro, Los Angeles, CA
• SoundGRO (Pierce County, WA)
• TAGRO (Tacoma, WA)
• TOPGRO (Los Angeles, CA)
• Tuscarora Landscaper’s Choice (Leesburg, VA)
• UAJA ComposT (Central Pennsylvania) (10)

Final Thoughts on Human Sewage Sludge in Compost

• If what homes, businesses, industry, hospitals and mortuaries put down drains was not so hazardous, the idea of using human waste for compost and fertilizer would be much safer. It’s not the poop that’s the issues, but the other things we put down the drain. To use biosolids safely, we’d need sweeping chemical reform on a national level to keep harmful chemicals off the market in the first place.
• Sewage sludge is commonly used in playgrounds, parks, athletic fields, gardens and golf courses.
• Sewage sludge in compost products could contain heavy metals, industrial chemicals, trace pharmaceuticals and hormone-disrupting chemicals and other toxic compounds.
• Certain crops grown in human sewage sludge have been shown to “take up” heavy metals and even phthalates, a common class of fragrance ingredients in everything from shampoo and soaps to lotions and makeup.
• Municipalities sometimes mix green waste with sewage sludge and give it away free.
• Your best bet is to make your own compost. Call any bagged compost or municipalities to find out the source of the compost.  United Sludge-Free Alliance notes that if the bag says topsoil, it is usually topsoil.  If the bag says it is humus from a location, it is probably all humus.  If the bag says compost and nothing else, it is a “crap shoot” at best.

Read Next: Dirty Dozen: Are You Eating the Most Pesticide-Laden Produce?