Pros and cons of biosolids as fertilizer

SIX NATIONS – The list of genuine concerns regarding the application of human waste as fertilizer are many, but the industry continues to thrive in Southern Ontario and Brant County. Six Nations Elected Council banned its use on Six Nations of the Grand River Territory several years ago and that ban remains in place, but Brant and Brantford have no such ban.

On paper, finding a use for the sludge that is left after raw municipal sewage is processed is a stroke of genius. The application has very positive results in fertilizing crops, and there is not much doubt of that. What’s more, it is free to the farmer. Although haulage and application is a cost, the use of biosolids is far cheaper than other fertilizers on the market.

Despite what proponents and suppliers of biosolids say, and with municipal government support, the risks are usually played down while the benefits of its use are played up.

As with most things, the protection of the environment and the health of people consuming the produce grown with biosolids over a long time, are secondary to finding a use for this nasty sludge, while making money doing so.

According to a published report by the Bioscience Resources Project, “Risk assessment is complex because Sludge Contains Highly Varied Amounts of Organic Chemicals, Toxic Metals, Chemical Irritants, and Pathogens. Furthermore, the effects of their interactions, long-term build-up in soils, leaching into waterways, and uptake into crops and the food system have not been well-studied. Thus, little is known about the long-term human heath and Ecological Consequences of Sludge Application. There is, however, clear scientific documentation of the sometimes deadly Direct Human Health Consequences of Land Application.  Furthermore, by bringing together and concentrating varied pathogens and antibiotics, Wastewater Treatment Selects Antibiotic Resistant Bacteria is a problem worldwide.”

This leads to strains of diseases that are resistant to medical antibiotics. This is a problem most countries around the world share however North America at large focuses far too much on low cost of its use and usually plays down the dangers of eating foods nourished by human waste.

Former Six Nations Elected Chief fought its use on the Grand River Watershed.

“I wish there were high-level talks but all we get is nothing,” Montour said at the time.

Montour banned its use on reserve but also wanted the same ban in Brant County, fearing runoff into the Grand River but was unsuccessful and biosolids continue to be spread on thousands of acres, which drain into Six Nations water source.

A steady parade of large tanker trucks roll from the Wesuuc Biosolids processing plant on Locks road across from the municipal dump. This proves the popularity of biosolids, or human waste sludge. But it also makes more research on the subject even more necessary, especially in the Brant/Brantford area where field runoffs go directly into the Six Nations water supply.

Although the process does eliminate several natural toxins and other unhealthy elements, even the most sophisticated human waste processing plants can not eliminate certain drugs elements introduced by the pharmaceutical industry and the for human and animal use, like antibiotics and some heavy metals. These elements can find their way into the food we eat and which grazing cattle eat and cause many chronic ailments.

But not all scientific studies have had the same results. Other studies have shown the danger in using biosolids is much less risky today than in past years of development. Proponents say, it is proven to be completely harmless.

The UNC Institute for the Environment released a study in 2009, which says “an initial literature review was completed to determine how detrimental the land application of biosolids really is to public health. Our group found that there is very little known about the health effects of biosolids land application, either in the short or long-term.”

In 1996, the NRC published Use of Reclaimed Water and Sewage Sludge in Food Crop Production. The report concluded that the application of biosolids to farmland, when practiced in accordance with existing federal guidelines and regulations, presents negligible risk to the consumer, to crop production, and to the environment. The report concluded that current technology to remove pollutants from wastewater, coupled with existing regulations and guidelines governing the use of reclaimed wastewater and sludge.

But it goes on to say, “like any nutrient-rich fertilizer, biosolids should only be applied in ways that minimize risk of leaching of nutrients or other constituents to groundwater or runoff to nearby surface waters.

Environmentally conscious farmers and governments around the world still have a number of concerns.

The Ecological Farmers Association of Ontario supports a moratorium to ban the spreading of biosolids on farm land and to support and ask for independent research on long term effects on farmland and surrounding ecosystems.

“In Ontario, two-thirds of all sewage sludge is disposed of by spreading it on farm fields –300,000 tonnes a year. Toronto alone contributes 80,000 tonnes a year,” according to EFAO studies. “Biosolids are praised for the high nutrient levels which are beneficial to the soil. But there can also be uncontrolled concentrations and mixtures of, namely: Bacteria, Viruses, Parasites, Endotoxins, Heavy metals like Arsenic, Lead, Mercury, Chromium, Cadmium, Molybdenum, Copper, Selenium, Zinc, Chemicals like PCB’s, PBDE’s (fire retardants), dioxins and furans, endocrine disruptors, polyaromatic hydrocarbons, and others discharged into sewers from home and industry as well as Antibiotics and other drugs flushed down toilets and drains.”

This study has discovered that significant amounts of the heavy metals in the biosolids have vanished from the plough depth of the fields. (The heavy metals are markers for some 10,000 potentially harmful chemicals in the sludge, which are not individually tested for.) Testing has revealed the metals did not migrate deeper into the soil, and while some leachate into surface waters was found, the rate of leachate could not account for the bulk of the missing material.

“The only clues to its disappearance were elevated levels of metals found in weeds adjacent to the spread fields,” says the study. “One of the independent studies, a study by OME/OMAFRA/WTI in Ontario reinforces the findings. That study found dioxins in known historic biosolids spread fields had also vanished. While neither Cornell nor OME/OMAFRA is prepared to state the obvious, the logical assumption is that these harmful chemicals were absorbed into the plants grown as food and fodder crops and are contaminating the entire food chain from vegetables and fruit fertilized with sludge (tobacco is the only crop that cannot be grown in biosolids in Ontario) to the meat, eggs, milk, and prepared foods from animals fed sludge-contaminated feeds.”

“Because 95 per cent of the uses of the antibacterial pesticide triclosan, and its cousin triclocarban, are in consumer products that are disposed of down residential drains, sewage and wastewater provide a prime medium for their entry into the larger environment.”

EPA, in its Targeted National Sewage Sludge Survey Report, found that triclosan was detected in 79 of a total of 84 sludge samples used in the survey.

“The beneficial reuse of digested municipal sludge as agricultural fertilizer represents a mechanism for the reintroduction of substantial amounts of [triclosan] into the environment,” the report concludes.