Sewer Sludge / Biosolids and the small matter of Determining Safety ...
Sewer sludge aka biosolids is NOT just human excrement - it is a concentration of all domestic and industrial pollutants that go down drains and sewers. It has some good stuff in it, which plants can use, but a huge load of thousands of other contaminants. "Land-applied municipal sewage sludge (biosolids) is a highly complex and unpredictable mixture of biological and chemical pollutants. Biosolids generated in our large industrialized urban centers is very likely the most pollutant- rich waste mixture of the 21st century." (Dr. Caroline Snyder)
The very limited testing done on contaminants in our sewage residuals relies on the old-fashioned single toxicity methodology. A recent article by Peter Montague, who has co-authored two books on toxic heavy metals, has outlined the many problems with this approach.
Firstly, he notes that,
"Risk assessment is easily manipulated. Two groups of fully qualified risk assessors, given identical data, can reach wildly different estimates of risk. Therefore, numerical risk assessment fails the acid test of science -- reproducible results -- and does not qualify as "science" or "scientific." Risk assessment is a political art that uses some scientific data. As EPA administrator William Ruckelshaus wrote in 1984, "We should remember that risk assessment can be like the captured spy: If you torture it long enough, it will tell you anything you want to know." "
Secondly, he notes that,
" Risk assessments have no reliable way to evaluate simultaneous exposures to multiple chemicals. Therefore, they create an imaginary world with a single-chemical exposure. In this imaginary world, a chemical exposure can be declared "safe" even though it actually may be quite harmful when combined with other exposures."
This is exactly what sludge defenders like Sally Brown and Lynda McCarthy do when they trot out their single toxin extrapolations around exposure and safety. Neither make any mention of the issues around combined exposures - this is simply poor science, and blinkered, biased support for the continuance of toxic sludge disposal on soils meant to sustain us.
This is the method used to support the assurances of safety by both the EPA and the OMRR regulations. It is faulty, simplistic and naïve.
Remember too that in order to qualify as Class A or Class B or Class A "EQ" ... they ONLY TEST for about a dozen metals and pathogens. This is absurd given the thousands of toxins known to be in these residuals. Not only do they not take into account the synergies between these contaminants, but they don't even test separately for things like solvents, PCBs, dioxins, microplastics, pharmaceuticals, fluoride, flame retardants, radioactive materials, nano-particles, superbugs and prions!!
Please read the article in full - http://www.truth-out.org/news/item/43517-the-precautionary-principle-asks-how-much-harm-is-avoidable-rather-than-how-much-harm-is-acceptable
For more on why the "risk assessments" made by both OMRR and EPA are faulty please see -
For more on the toxins found in our Sewer Sludges / "Biosolids" please see -
Household Chemicals and Drugs Found in Biosolids from Wastewater Treatment Plants https://toxics.usgs.gov/highlights/biosolids.html
Chemicals from Land-Applied Biosolids Persist in Soil https://toxics.usgs.gov/highlights/2014-06-10-biosolids_leach.html
Safety testing, by biosolids scientists, looks merely at single chemical toxicity amounts. This is faulty, simplistic, and outdated. As the scientists taking part in the Halifax Project have shown, it is the exposure to a variety of toxins in low-dose that can cause cancer. (The Halifax Project took place between 2012 and 2015 and it involved more than 350 cancer researchers and physicians from 31 countries … focused on the carcinogenic potential of low dose exposures to mixtures of chemicals in the environment - see http://www.gettingtoknowcancer.org/taskforce_environment.php) The absurd situation is that we have soil specialists, agronomists etc. determining the safety of something they are utterly unqualified to make such pronouncements about - this is the purview of chemists, doctors/oncologists.
The Risk Assessments for Sewage Sludge (Biosolids) are faulty. The sludge industry & government agencies charged with protecting human health rely on old, and incomplete assessment methods. Since Paracelsus (born in 1493) stated “the dose makes the poison,” this idea has formed the basis for the regulation of toxic chemicals, including the use of pesticides and pharmaceuticals. We now know that this truth is incomplete. It is not only the dose, but also the type of chemical, the timing of exposure, the combination of chemicals and individual risk factors that combine to produce toxic effects.
There are several important issues that those pushing "biosolids" as a fertilizer fail to take into account -
1. The full extent is unknown - While we are all chronically exposed to a toxic cocktail of industrial pollutants, the full impact of industrial chemicals on human health remains unknown. There are more than 80,000 industrial chemicals that are commercially produced
2. Tiny doses can have big effects - In the past it was thought that dose-response curves were linear, displaying a direct relationship between dose and toxicity. It is now known that dose-response curves can be non-linear or ‘non-monotonic’. This occurs when chemicals disturb the body’s regulatory processes rather than just impacting on target organs or tissues.
3. Biomagnification occurs up the food chain - Many toxic chemicals are fat soluble and last for decades in the environment where they undergo biomagnification (tissue concentrations increase) as they pass up the food chain.
4. Chemical cocktails are synergistic - While exposure to individual toxic chemicals can be harmful, exposure to chemical mixtures is even more harmful. It has been shown that chemical cocktails can produce ‘something from nothing’ with toxic mixture effects arising even when the level of each contaminant in the mixture is below its specific ‘NOAEL’ (no observable adverse effect limit). Such mixture effects are not accounted for when determining chemical safety, which is assessed one chemical at a time
(Adapted from "Ten Toxic Truths" By Professor Marc Cohen - https://www.organicgardener.com.au/blogs/ten-toxic-truths )