Yes, food is grown in sewage waste.

That’s a problem.

Darlene Schanfald for the Environmental Health News

You may not realize it but some foods you eat may have been grown in soil containing toxic sewage wastes. Labeling is not required.

In 2019, about 60 percent of sewage sludge from 16,000 wastewater processing facilities in more than 160 U.S. cities has been spread on our soils – farmland and gardens, as well as schoolyards and lawns.

The U.S. Environmental Protect Agency (EPA) allows this use of sewage waste, claiming it has beneficial use because it contains properties similar to fertilizer—certain heavy metals, phosphorus and nitrates—that could enhance soil conditions.

The agency does not require testing for other chemicals in the sewage waste. 

Yet, millions of tons of sewage are processed annually and the waste can contain upward of 90,000 chemicals plus and an array of pathogens, including mixtures of lead, mercury, arsenic, thallium, PCBs, PFAS, highly complex, superbugs, mutagens, pesticides, microplastics, radioactive wastes, pharmaceuticals, personal care products, steroids, flame retardants, dioxins, and/or their combinations.

Sewage treatment plants separate the processed sewage into solids and liquids (effluent), where these pollutants and pathogens concentrate.

The toxics-containing solids are often mixed with garden waste and sold for compost or recycled as fertilizers. These are spread on soils at farms, forests or recreational sites and can run off with stormwater into surface water bodies.

Currently the U.S. recycles 587 million gallons of this toxic effluent water each day for irrigation on agricultural land.

Florida, for instance, produces an estimated 340,000 dry tons of sewage solids annually, two-thirds of which are spread on land. California, arguably with the most sewage, "reclaims" at least 13 percent of its effluent; 31 percent is used for crop irrigation.

Long term damage from spreading sewage waste on land has led to many problems. For example, a variety of crops—including leafy greens and soybeans—used for food and animal fodder are known to have taken up sewage contaminants. The consequences? Contaminated food, loss of farmland and animals. Human illnesses and deaths have resulted from breathing the particulates.

Water, pollution and plastics

Warning sign on Lake Merritt, a large tidal lagoon in the center of Oakland, California. (Credit: Daniel Ramirez/flickr)

The EPA is currently writing a national plan for the use of sewage effluent, which they will call "recycled," "reclaimed," and "purified."

Effluent from sewage plants that is not "recycled" or "reclaimed" travels from pipes into nearby open water bodies. This not only contaminates aquatic waters and ecosystems, but the excess nitrogen can cause algae blooms and eutrophication, stealing needed oxygen from marine plants and animals.

Just this month, the Florida Senate Committee on Community Affairs recognized this threat by passing the Clean Waterways Act, CS/SB 712, "for all the reasons algae keeps blooming and fish keep dying." The bill tightens restrictions on sewage spills and sewage solids by moving septage to sewer systems and offering local governments a 50 percent matching grant to do this. 

The Act also regulates and ensures future septic tanks are designed, installed, operated and maintained to prevent nitrogen and phosphorus nutrient pollution, and also ensures that sewage solids are only applied to land high enough and dry enough to prevent interaction with groundwater.

In addition to excess nutrients, some plastic sources in the marine waters come from the release of sewage effluents. Microplastics that enter the marine waters can adsorb toxics, such as PCBs. 

Many of the microplastics are from personal care products and fleece fibers washed out from clothing in the laundry. The plastics and pollutants are now found in fin and shellfish and these travel up the food chain for consumption by higher animals, including humans.

Sewage contamination of our oceans directly affects the health of our air, wildlife and human health. 

For example, the pollution of Washington State's Puget Sound, stretching about 100 miles from the Pacific Ocean to beyond the capital city of Olympia, is estimated to be 60 percent from sewage.

Some states use effluent for augmenting and "enhancing" aquifers. This means injecting effluent into potential potable water systems.

California, Ohio, and other states allow municipalities to recycle it for potable uses after additional cleansing. Some microbrew beer companies are experimenting with reusing processed effluent. 

Antibiotic resistant genes are disseminated through effluent reuse. The point is, cleaner is not clean and no entity can test for all the pathogens and thousands of contaminants, or even know what to test for.

Alternatives exist

Rain garden in Lancaster County, Pa. (Credit: Chesapeake Bay Program/flickr)

Lapeer, Michigan; Marinette, Wisconsin; and Arundel, Maine, have ended the practice of spreading sewage waste on land after finding that PFAS, a class of harmful chemicals, are in grazing lands and farm soils. These pollutants are turning up in drinking water and some foods across the U.S. PFAS have been linked to low infant birth weights, kidney cancer, and a range of other diseases.

The EPA's Office of Inspector General's Water Division has several times warned EPA that its regulations are not effective in controlling the discharge of hundreds of hazardous chemicals to surface waters; that the EPA is unable to assess the impact of hundreds of unregulated pollutants in land-applied "biosolids" on human health and the environment; and that the public and researchers are not receiving complete and timely information about environmental conditions affecting human health.

Safer alternatives for recycling sewage wastes exist. Some U.S. cities are using pyrolysis—internal high heat methods that destroy pathogens and destabilize bonds of toxics, then capture the excess heat for energy purposes or other uses. Australia is piloting another high heat source—plasma arc. 

Remediation methods exist to lessen toxicity in soils and sediments. The EPA and states must insist municipalities investigate alternative methods for reuse of sewage wastes.

To stop poisoning soils, marine ecosystems, wildlife and our food system, governments must regulate the current practices as unsafe and promote new technologies to replace current sewage management.

Darlene Schanfald, Ph.D., has been active in environmental campaigns for more than three decades and has worked on sewage waste issues since 2000.