The dangers of our increasingly toxic world – and the rising levels of “forever chemicals” and nano- and micro-plastics – have again come to the fore, with the banning by US authorities of lethal food packaging, and study findings showing numerous traces of plastics in a number of placentas.
Now, fast-food wrappers and other grease-proofing materials containing per- and polyfluoroalkyl substances (PFAS) will no longer be sold for use in food packaging in America, the Food & Drug Administration (FDA) announced last week, as increasing research shows serious health effects linked to exposure of some types of PFAS.
This means major sources of dietary exposure to PFAS, like microwave popcorn bags, take-away cartons, and pet food bags, will all be eliminated.
The FDA cited evidence that exposure to some types of PFAS has been linked to serious health effects, reports Medpage Today.
For example, one study in military personnel linked testicular cancer to one PFAS chemical used to make products resistant to stains, grease, soil and water. Additionally, a systematic literature review linked PFAS exposure to overall poor kidney health.
And a recent longitudinal study found that greater consumption of tea, processed meats, and food prepared outside the home was associated with increased levels of PFAS in the body over time.
Last month, the CDC recommended that physicians consider blood testing patients for exposure to the endocrine-disrupting chemicals.
Moreover, scientists are finding that these “forever chemicals” are omnipresent, having been detected in the air, household products, food and even tap water.
PFAS is still allowed for limited use in cookware, food packaging and food processing equipment.
Microplastics in placentas
Science Alert reports that scientists found microplastics swimming in four different human placentas – which was just the tip of the iceberg.
Then, at the beginning of last year, researchers found microscopic particles of plastic waste in no fewer than 17 placentas. By the end of 2023, a local study in Hawaii analysed 30 placentas that were donated between 2006 and 2021, only to find plastic contamination had increased significantly over time.
Using a new technique, researchers have now identified tiny particles and fibres of plastic less than a micron in size in the largest sample of placentas yet. The study, by a team from the University of New Mexico, was published in Toxicological Science.
In all 62 tissue samples studied, the team found microplastics of various concentrations in every single one. These concentrations ranged from 6.5 to 685 micrograms per gram of tissue, which is much higher than levels found in the human bloodstream.
No one yet knows what this plastic pollution is doing – if anything – to the health of the foetus or the mother. While microplastics have been found in every major organ of the human body, including the brain, it’s unknown if these pollutants are temporary visitors or permanent and accumulating threats to health.
As environmental plastic pollution continues to worsen, contamination of the placenta is on track to only increase, as humans breathe in and ingest more plastic than ever before.
“Dose makes the poison,” said biologist Matthew Campen from the University of New Mexico.
“If the dose keeps going up, we start to worry. If we’re seeing effects on placentas, then all mammalian life on this planet could be affected. That’s not good."
Determining how much microplastics are accumulating in human tissue has proved extremely difficult, given the very small size of these particles.
For years now, scientists have been working on a solid detection method that can quantify the mass of these pollutants and determine their specific brand of plastic. Only then can the impact on health be properly evaluated.
The new study used a novel, high resolution technique to scan for plastics in human blood and tissue. First, researchers separated the majority of biological material from plastic solids, using chemicals and extremely high speed ultracentrifuges to separate very small molecules.
Then, they broke down the polymers to determine their specific compounds.
When applied to the 62 placenta samples, the technique revealed that more than half of all plastics found in placenta are polyethylene – the most commonly produced plastic on our planet, responsible for most single-use bags and bottles.
Other plastic particles identified in the placenta include polyvinyl chloride, nylon, and polypropylene, all of which are probably several decades old, having been weathered and oxidised for years in the environment before being inhaled or ingested by humans.
“This method,” the authors said, “paired with clinical metadata, will be pivotal to evaluating potential impacts of nano MPs on adverse pregnancy outcomes.”
In research on mini-models of the human intestine, microplastics show potentially dangerous immune effects. What’s more, early experiments on mice suggest that micro- and nanoplastics have the “potential to disrupt foetal brain development, which in turn may cause suboptimal neurodevelopmental outcomes”.
The reasons for the wide range of microplastic concentrations found in human organs, including the placenta, is currently unknown. It could be due to analytical error, or, researchers say, it could be due to a combination of environmental, dietary, genetic, maternal age, and lifestyle factors.
“The factors that drive such extreme concentration ranges are not known, nor is it apparent if such concentrations contribute negatively to growth and development of the placenta or foetus, or to other maternal health consequences,” the study team said.
“The placenta receives relatively high blood flow and takes up a great deal of nutrients from the maternal blood, which might make it more highly exposed; the extent to which nano- and microplastic pollution can be carried across the complex placental barrier, either passively or actively, requires further investigation.”
Study 1 details
Quantitation and identification of microplastics accumulation in human placental specimens using pyrolysis gas chromatography mass spectrometry
Marcus Garcia, Rui Liu, Matthew Campen et al
Published in Toxicological Science on 17 February 2024
Abstract
The exponential increase in global plastic usage has led to the emergence of nano- and microplastic (NMP) pollution as a pressing environmental issue due to its implications for human and other mammalian health. We have developed methodologies to extract solid materials from human tissue samples by saponification and ultracentrifugation, allowing for highly specific and quantitative analysis of plastics by pyrolysis-gas chromatography and mass spectrometry (Py-GC-MS). As a benchmark, placenta tissue samples were analysed using fluorescence microscopy and automated particle count, which demonstrated the presence of > 1-micron particles and fibers, but not nano-sized plastic particles. Analyses of the samples (n = 10) using Attenuated Total Reflectance—Fourier Transformed Infrared spectroscopy indicating presence of rayon, polystyrene, polyethylene, and unclassified plastic particles. By contrast, among 62 placenta samples, Py-GC-MS revealed that microplastics were present in all participants placentae, with concentrations ranging widely from 6.5–685 µg NMPs per gram of placental tissue, averaging 126.8 ± 147.5 µg/g (mean ± SD). Polyethylene was the most prevalent polymer, accounting for 54% of total NMPs and consistently found in nearly all samples (mean 68.8 ± 93.2 µg/gram placenta). Polyvinyl chloride and nylon each represented approximately 10% of the NMPs by weight, with the remaining 26% of the composition represented by 9 other polymers. Together, these data demonstrate advancements in the unbiased quantitative resolution of Py-GC-MS applied to the identification and quantification of NMP species at the maternal-foetal interface. This method, paired with clinical metadata, will be pivotal to evaluating potential impacts of NMPs on adverse pregnancy outcomes.
Study 2 details
Temporal trends in microplastic accumulation in placentas from pregnancies in Hawaii
Rodrigo Barbano Weingrill, Men-Jean Lee, Johann Urschitz et al.
Published in Environment International in October 2023
Abstract
Microplastics are created for commercial use, are shed from textiles, or result from the breakdown of larger plastic items. Recent reports have shown that microplastics accumulate in human tissues and may have adverse health consequences. Currently, there are no standardised environmental monitoring systems to track microplastic accumulation within human tissues. Using Raman spectroscopy, we investigated the temporal exposures to plastic pollution in Hawaiʻi and noted a significant increase in the accumulation of microplastics in discarded placentas over the past 15 years, with changes in the size and chemical composition of the polymers. These findings provide a rare insight into the vulnerability and sensitivity of Pacific Island residents to plastic pollution and illustrate how discarded human tissues can be used as an innovative environmental plastic pollution monitoring system.
Medpage Today article – FDA Announces End to ‘Forever Chemicals’ in US Food Packaging (Open access)
See more from Medical Brief archives:
Stringent EPA limits for ‘forever chemicals’ in drinking water
US states crack down on toxic ‘forever chemicals’
‘Forever chemicals’ detected in all umbilical cord blood in 40 studies
Study finds microplastics in heart tissues, pre- and post-surgery