It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, June 09, 2020
Study reveals birth defects caused by flame retardant
A new study from the University of Georgia has shown that exposure to a now-banned flame retardant can alter the genetic code in sperm, leading to major health defects in children of exposed parents.
Published recently in Scientific Reports, the study is the first to investigate how polybrominated biphenyl-153 (PBB153), the primary chemical component of the flame retardant FireMaster, impacts paternal reproduction.
In 1973, an estimated 6.5 million Michigan residents were exposed to PBB153 when FireMaster was accidentally sent to state grain mills where it made its way into the food supply. In the decades since, a range of health problems including skin discoloration, headache, dizziness, joint pain and even some cancers have been linked to the exposure.
More striking, the children of those who were exposed seemed to experience a host of health issues as well, including reports of hernia or buildup in the scrotum for newborn sons and a higher chance of stillbirth or miscarriage among adult daughters.
Yet, little work has been done to understand how the chemical exposure could have impacted genes passed from an exposed father, said study author Katherine Greeson.
"It is still a relatively new idea that a man's exposures prior to conception can impact the health of his children," said Greeson, an environmental health science doctoral student in Charles Easley's lab at UGA's College of Public Health and Regenerative Bioscience Center.
"Most studies where a toxic effect is observed in children look only to the mothers and the same has been true of studies conducted on PBB153," she said.
Greeson and a team of researchers from UGA and Emory University used a unique combination of observational and laboratory approaches to demonstrate how PBB153 acted on sperm cells.
"Typically, scientific studies are either epidemiological in nature and inherently observational or focus on bench science, but in this study, we did both," said Greeson.
This approach allowed the researchers to mimic the known blood exposure levels of PBB153 in a lab environment.
"We were uniquely able to recreate this effect using our previously characterized human stem cell model for spermatogenesis," she said, "which allowed us to study the mechanism that causes this effect in humans."
The team looked at the expression of different genes in their human spermatogenesis model after dosing with PBB153 and found marked alterations in gene expression between dosed and undosed cells, specifically at genes important to development, such as embryonic organ, limb, muscle, and nervous system development.
"PBB153 causes changes to the DNA in sperm in a way that changes how the genes are turned on and off," said Greeson. "PBB153 seems to turn on these genes in sperm which should be turned off," said Greeson, which may explain some of the endocrine-related health issues observed in the children of exposed parents.
Though the study used this model to directly replicate exposure to PBB153, Greeson says this approach could be used to better understand the impact of other environmental exposures on reproduction, including large-scale accidental exposures to toxic chemicals or everyday exposures.
"Hopefully this work will lead to more studies combining epidemiology and bench science in the future, which will tell us more about why we're seeing an effect from an environmental exposure in human populations and encourage experimental studies to more closely mimic human exposures," she said.
The study, "Detrimental Effects of Flame Retardant, PBB153, Exposure on Sperm and Future Generations," published May 22.
More information:Katherine Watkins Greeson et al, Detrimental effects of flame retardant, PBB153, exposure on sperm and future generations,Scientific Reports(2020).DOI: 10.1038/s41598-020-65593-x
Harmful flame retardants may be lurking on your hands and cell phone, according to a peer-reviewed study published today in Environmental Science & Technology Letters.
The researchers found that halogenated flame retardants added to plastic TV cases can move from the TV to indoor air and dust, to hands, and then to cell phones and other hand-held electronic devices. Once on your cell phone, that surface provides an ongoing source of exposure to these chemicals each time you touch your cell phone.
"It's well-known that viruses are transferred between surfaces and hands," said co-author Miriam Diamond, a Professor in the Department of Earth Sciences at the University of Toronto. "Our study shows that toxic chemicals like flame retardants do the same. That's another reason we should all wash our hands often and well."
Halogenated flame retardants, such as polybrominated diphenyl ethers, are known to pose a health risk to children. Previous studies have found that exposure to these chemicals can cause lower IQ in children and behavioral problems.
The authors were surprised to find higher levels of almost all halogenated flame retardants, all organophosphate flame retardants, and phthalate plasticizers on the surfaces of cell phones and other hand-held electronic devices like tablets, compared to non-hand-held devices like desktop computers. This included finding higher levels of long-banned polybrominated diphenyl ethers on new cell phones than on the surfaces of older desktop computers. The researchers suggest that these old chemicals got to the new phones by transfer from hands.
Why are TVs a source of flame retardants? The answer lies in the odd story of old "instant-on" cathode ray tube TVs manufactured in the 1970s. This technology, which involved warming the cathode ray tube so that the TV would immediately project an image when turned on, resulted in several hundred TV fires in the 1970s. The response was to recommend flammability standards that led to large amounts of flame retardants added to the outside casings of the TVs.
However, those same levels of flame retardants continued to be used —as much as a quarter of the weight of the plastic case— even after the industry moved to current TVs that pose a minimal fire risk. Thus, recently manufactured TVs contain high levels of unnecessary and harmful flame retardants. We are exposed because the flame retardants are not bonded to the cases, but escape over time to contaminate our indoor environments.
"If a flame retardant is used in the TVs, we then find it throughout the house, including on the hands of the resident," said co-author Lisa Melymuk, an Assistant Professor of Environmental Chemistry at Masaryk University.
The COVID-19 pandemic has taught us to wash our hands regularly and well to avoid getting ill. The results of this study suggest that frequent handwashing can also reduce our exposure to harmful flame retardants.
"However, to reduce health harm from flame retardants, the electronics industry should stop their unnecessary use," said Arlene Blum, Executive Director of the Green Science Policy Institute. "Fire safety can be achieved by innovative product design and materials instead of the use of toxic chemicals that can remain in our homes—and in us—for years to come."
More information: Congqiao Yang et al, Are We Exposed to Halogenated Flame Retardants from both Primary and Secondary Sources?, Environmental Science & Technology Letters (2020). DOI: 10.1021/acs.estlett.0c00268
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