Are biosolids safe?

25 08 2015

In a recent email from the Green Science Policy Institute, Arlene Blum mentioned that she was just back from Fluoros 2015, which aims to examine the “state of the science” on fluorinated organic compounds in the environment. Her take away was that many of these fluorinated compounds (like those found in fire retardants)  are found in vegetables such as lettuce, tomatoes and strawberries. The assumption is that these man-made chemicals are found in our vegetables because biosolids were used as fertilizer and reclaimed water was used for irrigation.

How does this happen?

First we have to know what a biosolid is: Bascially, biosolids are made from treated sewage sludge, under another (less prejudicial) name. According to the U.S. Environmental Protection Agency, biosolids are “nutrient-rich organic materials”, which contain useful amounts of plant nutrients such as nitrogen, phosphorus and micronutrients. Because it is made from treated sewage, it’s considered safe for use as fertilizer or land reclamation, and about 50% of all biosolids produced in the U.S. are being used as fertilizer, though only about 1% of cropland has biosolids applied.  But the use is growing because the cost to farmers is far less than for chemical fertilizers – by a factor of 4![1]   They can also be composted and sold for use on lawns and home gardens.

Sounds like a dream, right? Using  sewage sludge as fertilizer is a sweet way to get rid of the mountain of sludge produced in the U.S. each year.   Sludge management is an integral part of any municipal waste management system. The most common disposal method is incineration (which has its own problems) and landfills, storage in huge sludge ponds, dried in the sun or dumped in the oceans. But ocean dumping, which created vast dead moon-scapes on the ocean floor, was halted by the Ocean Dumping ban of 1987. Thus the policy of disposing of sludge by spreading it on agricultural land (a policy given the name “land application”) was born.     biosolidsGOC

The problem with biosolids is that most municipal treatment facilities are not able to remove the many chemicals found in sewage. The four main categories of potential pollutants – nutrients, pathogens, toxic organics, and heavy metals – behave differently and cannot all be managed by any single kind of treatment. The goal of “safe management” of such a complex toxic mixture cannot be met at a reasonable cost.

The EPA itself conducted the national Sewage Sludge Survey (NSSS) in 1988 to get information on pollutants found in treated biosolids. They found dozens of hazardous substances, including heavy metals, organics, PBDE’s, pharmaceuticals, steroids and hormones[2] in ALL the sludge samples the EPA took around the USA.

Rolf Halden is a professor at Arizona State University, member of the adjunct faculty at Johns Hopkins and an expert on the environmental impacts of industrial chemicals. His lab recently used treated sewage sludge to identify and prioritize persistent bioaccumulative chemicals.[3] The study found that chemicals contributed between 0.04% – 0.15% of the total dry mass of biosolids produced in the USA annually, which is equivalent to 2,866 – 8,708 tons of chemicals. The top individual chemicals found included:

  • Brominated fire retardants
    • DecaBDE
    • pentaBDE
    • 1,2-bis(2,4,6 tribromophenoxy
    • ethane
  • Surfactants
    • Nonylphenol (NP) and their ethoxylates (NPEOs) – both used in textile processing
  • Antimicrobials
    • Triclosan and triclocarban
  • Antibiotics
    • Azithromycin
    • Ciprofloxacin
    • ofloxacin

The Centers for Disease Control and Prevention (CDC) did a comprehensive exposure assessment of environmental chemicals found the U. S. population. They found about 139 organic chemicals in human blood, serum, urine and tissue samples. About 70% of the chemicals found in biosolids are also found in humans.

New studies have shown that:

  • Sewage sludge is mutagenic (it causes inheritable genetic changes in organisms), but no one seems sure what this means for human or animal health. Regulations for the use of sewage sludge ignore this information.
  • Two-thirds of sewage sludge contains asbestos. Because sludge is often applied to the land dry, asbestos may be a real health danger to farmers, neighbors and their children. Again, regulations don’t mention asbestos.
  • Governments issue numeric standards for metals. However, the movement of metals from soils into groundwater, surface water, plants and wildlife – and of the hundreds of other toxins in sludge – are poorly understood.
  • Soil acidity seems to be the key factor in promoting or retarding the movement of toxic metals into groundwater, wildlife and crops. The National Research Council (NRC) of the National Academy of Sciences gives sewage sludge treatment of soils a clean bill of health in the short term, “as long as…acidic soils are agronomically managed.” However the NRC acknowledges that toxic heavy metals and persistent organic pollutants can build up in treated soils.
  • There is good reason to believe that livestock grazing on plants treated with sewage sludge will ingest the pollutants – either through the grazed plants, or by eating sewage sludge along with the plants. Sheep eating cabbage grown on sludge developed lesions of the liver and thyroid gland. Pigs grown on corn treated with sludge had elevated levels of cadmium in their tissues. An AP story published in 2008 documented that milk sold throughout the U.S contained high levels of thallium (the primary toxin in rat poison), which had been present in the sewage sludge spread on crops fed to dairy cows.[4]
  • Small mammals have been shown to accumulate heavy metals after sewage sludge was applied to forestlands.
  • Insects in the soil absorb toxins, which then accumulate in birds.
  • It has been shown that sewage sludge applied to soils can increase the dioxin intake of humans eating beef (or cow’s milk) produced from those soils.
  • Traces of prescription drugs and household chemicals were found deep in the soil as a result of a couple of decades of use of biosolids as fertilizer.[5]

A study done in Sweden found that scientists have found antibiotic resistant “super bugs” in sewage sludge; they’re sounding the alarm about the danger of antibiotic resistant genes passing into the human food chain. Of the samples collected, 79% tested positive for the drug-resistnat vancomycin-resistant enterococci (VRE)

Astonishingly, in a November, 1990 edition of the United States Federal Register, the Environmental Protection Agency (EPA) had this to say of sewage sludge: “Typically, these constituents may include volatiles, organic solids, nutrients, disease-causing pathogenic organisms (bacteria, viruses, etc.), heavy metals and inorganic ions, and toxic organic chemicals from industrial wastes, household chemicals and pesticides.”

Not all contaminants are created equal:  some chemicals are stored in the human body, and others pass through it.  Some break down in our digestive system, and others don’t.  Each person is different, with a different body size, stage of development and metabolism.   The same chemical may wreak devastating effects if a pregnant woman eats it but may go unnoticed if eaten by a man.  And remember, chemicals are synergistic, and very little is known about interactions between low levels of large numbers of chemicals.  As an example, take the chemical triclosan, one of the antimicrobials that Rolf Halden’s lab found in highest quantities in treated sludge. Triclosan has been used for several decades in antibacterial products like soaps, deodorants and cosmetics.  It is also nearly universally found in sewage sludge.  A recently published study found that soybeans planted in soil containing triclosan took the triclosan up into their beans.

Triclosan is a suspected endocrine disruptor and recent CDC reports show more than a 40 percent increase in triclosan levels in the urine of Americans over a recent two-year period.  The amount in our bodies can’t be blamed entirely on sewage sludge; humans can absorb triclosan through their skin and those who use triclosan-containing toothpastes put the chemical directly into their mouths.   But at what point does exposure to triclosan become more than an individual body can bear?

According to the EPA, about half of all sewage sludge is applied to land, but it is only applied to about one percent of the nation’s farmland.  The likely result is that, if dangers do lurk in the sludge applied to land, we rarely find out about them.

Most people’s chances of eating enough tainted food from farms that apply sewage sludge as fertilizer to cause an acute reaction are pretty slim.  The chance that anyone who got sick would be able to correctly trace his or her illness back to the farm and to sewage sludge is even smaller.  However, a lack of easily traceable acute illnesses does not prove that sewage sludge is safe.  Health harm due to exposure to low levels of toxins over a long period of time is no more acceptable than acute problems, even if they are less obvious.

As a consumer, the only sure way to avoid food grown in sewage sludge is to buy organic food (or grow your own).  If you are a gardener and you wish to avoid sewage sludge fertilizers or composts, avoid any product that says it contains “biosolids.”  Last, if you wish to keep sewage sludge from being spread on farm fields near where you live, you can take action locally to make it illegal in your city or county.

[1] “Davison, Janet, “Earth Day: Is sewage sludge safe for farm fields?”, CBC news Canada, April 22, 2014.

[2] EPA , “Targeted National Sewage Sludge Survey Statistical Analysis Report”, revised April, 2009

[3] Halden, Rolf et al; “Wastewater treatment plants as chemical observatories to forecase ecological and human health risks of manmade chemicals”, Scientific Reports, January 2014

[4] Hellprin, John and Vineys, Kevin: “Sewage-based fertilizer safety doubted”, USA Today; 3.6.2008

[5] Bienkowski, Brian, “Farm sludge contaminates soil with drugs, other chemicals”, Environmental Health News, May 2014.


Asbestos – and fire retardants.

24 10 2011

A half century ago, asbestos – a ” 100% natural” material by the way –  was hailed as the wonder fiber of the 20th century.   It was principally used for its heat resistant properties and to protect property (and incidentally, human lives) from the ravages of fire. Because of this, asbestos was used in virtually all industrial applications as well as the construction of buildings and sea-going vessels. In the United States, asbestos is still legally used in 3,000 different consumer products, predominantly building insulation (and other building materials), automobile parts such as brake pads, roofing materials, floor tiles. Since asbestos became known to be a potent human health risk, many manufacturers found alternatives to asbestos:  for example, since the mid-1990s, a majority of brake pads, new or replacement, have been manufactured instead with linings made of ceramic, carbon, metallic and aramid fiber( Twaron or Kevlar – the same material used in bulletproof vests).

According to the United States Environmental Protection Agency, three of the major health effects associated with asbestos exposure include:

  • Asbestosis —  a serious, progressive, long-term non-cancer disease of the lungs. It is caused by inhaling asbestos fibers that irritate lung tissues and cause the tissues to scar. The scarring makes it hard for oxygen to get into the blood. The latency period (meaning the time it takes for the disease to develop) is often 10–20 years. There is no effective treatment for asbestosis.
  • CancerCancer of the lung, gastrointestinal tract, kidney and larynx have been linked to asbestos. The latency period for cancer is often 15–30 years.
  •  Mesothelioma — Mesothelioma is a rare form of cancer that is found in the thin lining (membrane) of the lung, chest, abdomen, and heart. Unlike lung, cancer, mesothelioma has no association with smoking. The only established causal factor is exposure to asbesto  fibers. The latency period for mesothelioma may be 20–50 years. The prognosis for mesothelioma is grim, with most patients dying within 12 months of diagnosis.  This is why great efforts are being made to prevent school children from being exposed.

Worldwide, 52 countries (including those in the European Union) have banned the use of asbestos, in whole or in part.  In the United States, only six categories of products can NOT contain asbestos:  flooring felt, rollboard, and corrugated, commercial, or specialty paper. In addition, there is a ban on the use of asbestos in products that have not historically contained asbestos, otherwise referred to as “new uses” of asbestos.   

So today, asbestos remains in millions of structures throughout the country, as many people find out (to their dismay) when they are planning to repaint their home or do other remodeling tasks and must deal with the EPA rules for safe disposal or removal of products which may contain asbestos.   Millions of people are exposed at home or in their workplace by the monumental quantities of asbestos that remain in the built environment — the attic insulation in 30 million American homes, for instance — following decades of heavy use.  It also remains heavily used in brake shoes and other products, directly exposing auto mechanics and others who work with the materials, and indirectly exposing consumers and workers’ families.

No safe level of minimum exposure has ever been established for asbestos. Many of the first cases of mesothelioma were persons who never directly handled asbestos as part of their jobs. An early case in South Africa occurred in a young girl whose job it was to empty the pockets of miners before dry cleaning their clothes. The asbestos dust in the miners’ pockets made her fatally ill.[1]   People who have worked in plumbing, steel, insulation and electrical industries have very high chances of suffering from asbestos-related disease. In fact, they could have passed it on to their family members through the dust that could have clung to their shirts, shoes and other personal belongings.

Today, even though global asbestos use is down, there are more than 10,000 deaths per year due to the legacy of asbestos exposure.[2] Asbestos kills thousands more people each year than skin cancer, and kills almost as many people as are slain in assaults with firearms

With the science to back up the claims that asbestos is a serial killer, and with global use on the downward swing, wouldn’t you think that deaths from asbestos exposure would be going down?  Yet, the U.S. EPA reports that asbestos related deaths are increasing  and, according to the studies cited by the Environmental Working Group, many believe that  the U.S. asbestos disease epidemic may not even peak for another ten years or more.

This ongoing increase in asbestos mortality is due largely to the fact that asbestos-caused cancers and other diseases have a 20 to 50 year latency period, meaning that individuals exposed in the 1960s and 1970s are just now dying from their exposure. Better tracking accounts for the dramatic increase in mesothelioma mortality reported in 1999, but lung cancer deaths from asbestos are not reported at all, and asbestosis is still dramatically underreported even in worker populations where asbestos exposure is well established.

The legacy of asbestos, in the United States as in other countries such as the U.K. and Australia, is that the initial use of asbestos as a miracle fiber quickly gave rise to a burgeoning industry and adoption of asbestos in many products.   This happened long before any detrimental health effects were known, so now,  many years later,  asbestos related disease is killing significant numbers of people.  Environmental Health Perspectives last year published “The Case for a Global Ban on Asbestos”[3]

If you google “new asbestos” you can find many materials that people claim could be the “new asbestos” – nanotechnology, fly ash and climate-change litigation for example – because these are all being widely adopted before being well understood, and may well leave a legacy of death and destruction similar to that of asbestos.  Well, okay, litigation has not been known to kill directly, but you understand the point I’m trying to make.

I’d like to nominate flame retardant chemicals used in our furniture, fabrics and baby products – as well as a host of other products – as being in the running for the new asbestos.  These chemicals are called halogenated flame retardants, such as polybrominated diphenyl ethers – commonly known as PBDE’s.  Women in North America have 10 to 40 times the levels of the PBDEs in their breast milk, as do women in Europe or in Asia. And these chemicals pass through the placenta and are found in infants at birth, making a double dose of toxins for young children when they are most vulnerable.  When tested in animals, fire retardant chemicals, even at very low doses, can cause endocrine disruption, thyroid disorders, cancer, and developmental, reproductive, and neurological problems such as learning impairment and attention deficit disorder.   In humans, these chemicals are associated with reduced IQ in children, reduced fertility, thyroid impacts, undescended testicles in infants (leading to a higher cancer risk), and decreases in sperm quality and function.Ongoing studies are beginning to show a connection between these chemicals and autism in children.(4)  Pregnant women have the biggest cause for concern because animal studies show negative impacts on brain development of offspring when mothers are exposed during pregnancy. And bioaccumulating PBDEs can stay in our bodies for more than a decade.

A study published last week in the Environmental Health Perspectives  points to California’s unique furniture flammability standard called Technical Bulletin 117, or TB117, as the major reason for high fire retardant levels in California. The California standard, passed in 1975, requires that polyurethane foam in upholstered furniture be able to withstand an open flame for 12 seconds without catching fire. Because there is no other state or federal standard, many manufacturers comply with the California rule, usually by adding flame retardants with the foam.

The startling and disturbing result of the published study in Environmental Health Perspectives is that Latino children born in California have levels of PBDE in their blood seven times higher  than do children who were born and raised in Mexico.[5]  In general, residents of California have higher rates of PBDE in their blood than do people in other parts of the United States.

A home can contain a pound or more of fire retardants that are similar in structure and action to substances such as PCBs and DDT that are widely banned. They leak out from furniture, settle in dust and are taken in by toddlers when they put their hands into their mouths. A paper published in Environmental Science & Technology [6] also finds high fire retardant levels in pet dogs. Cats, because they lick their fur, have the highest levels of all.

One troubling example is chlorinated Tris, a flame retardant that was removed from children’s pajamas in the 1970s largely based on research done by Dr. Arlene Blum, a biophysical chemist, after it was found to mutate DNA and identified as a probable human carcinogen.  In the journal Environmental Science and Technology, new research published in 2011 shows that chlorinated Tris was found in more than a third of the foam samples tested – products such as nursing pillows, highchairs, car seats and changing pads.[7]

Tris is now being used at high levels in furniture being sold in California to meet the California standard.

The benefits of adding flame retardants have not been proved. Since the 1980s, retardants have been added to California furniture. From 1980 to 2004, fire deaths in states without such a standard declined at a similar rate as they did in California. And when during a fire the retardants burn, they increase the toxicity of the fire, producing dioxins, as well as additional carbon monoxide, soot and smoke, which are the major causes of fire deaths.

So why are we rolling the dice and exposing our children to substances with the potential to cause serious health problems when there is no proven fire safety benefit?

Under current law, it is difficult for the federal Environmental Protection Agency to ban or restrict chemicals – current federal  oversight of chemicals is so weak that manufacturers are not required to label products with flame retardants nor are they required to list what chemicals are used.[8]. Even now, the agency has yet to ban asbestos!

“We can buy things that are BPA free, or phthalate free or lead free. We don’t have the choice to buy things that are flame-retardant free,” says Dr. Heather Stapleton, an assistant professor of environmental chemistry at Duke University. “The laws protect the chemical industry, not the general public.”

The Consumer Product Safety Commission has been working on a federal flammability standard for upholstered furniture for 16 years. The current proposal would allow manufacturers to meet the flammability standard without fire retardants. An agency spokesman said that “additional research looking into consumer exposure and the impact of chemical alternatives is needed.”

This year, California State Sen. Mark Leno sponsored California Senate Bill 147, the Consumer Choice Fire Protection Act. The bill called for an alternative furniture flammability standard that would give consumers the choice to purchase furniture that is fire-safe and nontoxic.

However, aggressive lobbying in the form of multimillion-dollar campaigns from “Citizens for Fire Safety” and other front groups funded by three bromine producers –  Albemarle, Chemtura and Israeli Chemicals Ltd. –  resulted in a defeat of this bill in March, 2011.  Their main argument was that new flame retardants – similar in structure and properties to the old ones and lacking any health information – were safe.  This despite  opposition which included 30 eloquent firefighters, scientists, physicians and health officers representing thousands of Californians.

Although we stopped most uses of asbestos decades ago, workers and others inadvertently exposed continue to die from its long-term effects.  Let’s not add more chemicals to this sad list.

[5]  Eskenazi, B., et al., “A Comparison of PBDE Serum Concentrations in Mexican and Mexican-American
Children Living in California”,

[6]  Vernier, Marta and Hites, Ronald; “Flame Retardants in the Serum of Pet Dogs and in their Food”, Environmental Science and Technology, 2011, 45 (10),  pp4602-4608.

[7]  Martin, Andrew, “Chemical Suspected in Cancer is in Baby products”, The New York Times, May 17, 2011.

[8]  Ibid.


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