Plastic is such a ubiquitous part of modern life that it’s hard to imagine a world without it. But in the grand scheme of things, plastics are still a new invention.
As noted by Pete Myers, the chair, founder, and chief scientist of Environmental Health Sciences, there’s a lot we don’t know about plastics and health—but then, there’s a lot that we do.
Particularly when it comes to the chemicals in plastics, much is known about the risks they pose to human health, including to future generations through intergenerational endocrine disruption.
“It’s enough to give me great pause,” says Myers.
Endocrine disruptors—which are widespread in plastic products and similar in structure to natural sex hormones such as estrogen—interfere with normal hormone function, and more. According to Myers and other researchers, these chemicals jeopardize the reproductive health—and continuation of—the entire human race. [1]
“Your hormones have been hijacked. Your body’s astonishing, finely calibrated signal system—a system that controls everything from your weight to your fertility to your mood—has been scrambled by loosely regulated chemicals manufacturers use in a myriad of ways including in consumer products,” says Myers.
Male Fertility Is on the Decline, Could Reach Zero by 2045
Myers highlights the book “Count Down,” written by Shanna Swan, a reproductive epidemiologist at Mount Sinai’s Icahn School of Medicine. It’s based on a 2017 study she co-wrote, which found sperm counts dropped by 59.3 percent from 1973 to 2011.[2]The most significant declines were found in samples from men in North America, Europe, Australia and New Zealand, where many had sperm concentrations below 40 million/ml, which is considered the cutoff point at which a man will have trouble fertilizing an egg. Overall, men in these countries had a 52.4 percent decline in sperm concentration and a 59.3 percent decline in total sperm count (sperm concentration multiplied by the total volume of an ejaculate).
The book expands on what Swan describes as an impending fertility crisis; along with the dropping sperm counts, changes in sexual development pose a threat to human survival.
“The current state of reproductive affairs can’t continue much longer without threatening human survival,” warns Swan.[3] In fact, she estimates that if current projections continue, sperm counts could reach zero in 2045.
Global fertility rates are also falling, reaching 2.4 births per woman in 2018, down from 5.06 in 1964. Fertility rates in about 50 percent of countries worldwide are at 2.1, which is below population replacement level.
This cataclysmic drop in fertility rates makes human beings an endangered species, according to Swan and the generally accepted criteria for defining an endangered species. Within a generation, we could see a staggering decline in human reproduction. While there are numerous factors involved—including contraception and costs of raising children—biological reasons, such as declining sperm counts, increasing miscarriage rates, and genital abnormalities, are also driving down birth and fertility rates.
Has the ‘Count Down’ to Infertility Begun?
“Count Down” brings some little-known findings into the spotlight, like the fact that a significant part of the global population may not be able to reproduce without technological assistance come 2050.[6] Men today have about half the number of sperm compared to their grandfathers.There appears to be a synergy occurring as well, which the book dubs “the 1 percent effect.” Sperm count, testosterone, and fertility are all dropping at about 1 percent a year while testicular cancer and miscarriage are rising at about the same rate.[8]
Studies continue to link endocrine-disrupting chemical (EDC) exposure to reproductive health problems. One review of 35 studies looked at one common EDC—Bisphenol A.
Another EDC used for making plastics more flexible is known as di-(2-ethylhexyl)phthalate (DEHP), a phthalate plasticizer.
Environmental Chemicals Causing Fertility Declines
A number of chemicals are wreaking havoc with human fertility. EDCs interfere with endogenous hormones, and it’s been found that some effects of exposure persist in future generations, even among males that weren’t directly exposed.[11]Research published in PLOS Genetics, for instance, found that exposing male mice to ethinyl estradiol, a synthetic sex hormone found in birth control pills, causes developmental problems in the reproductive tract, thereby lowering sperm counts (men may be exposed to birth control pills through contaminated water and other sources).
This study also revealed the generational effects of EDCs. Environmental Health News reported:[12]
“They observed adverse effects starting in the first generation of mouse lineages where each generation was exposed for a brief period shortly after birth. The impacts worsened in the second generation compared to the first, and by the third generation the scientists were finding animals that could not produce sperm at all.”
“This latter condition was not seen in the first two generations exposed. Details of the experimental results actually suggested that multiple generations of exposure may have increased male sensitivity to the chemical.”
Other research adds further evidence that environmental chemicals are involved in fertility declines. A study published in Scientific Reports in 2016 found that dogs living in human households suffered similar declines in sperm quality to humans, with sperm motility declining by 30 percent over a 26-year period.[13]
In the canine study, the researchers linked certain environmental chemicals to sperm problems and suggested they could also be responsible for the sperm quality declines in humans—a notion supported by a 2019 follow-up study also published in Scientific Reports.[14]
Researchers from the University of Nottingham used sperm samples from 11 men and nine dogs from the same U.K. region. They exposed the sperm to doses of two types of environmental chemicals, diethylhexyl phthalate (DEHP) and polychlorinated biphenyl 153 (PCB153), currently found in the environment. The result was reduced sperm motility and increased DNA fragmentation.
Top Sources of Endocrine Disruptors
The Environmental Working Group (EWG) named the following 12 chemicals in their “dirty dozen” list of EDCs:[16]- Bisphenol-A (BPA)
- Dioxin
- Atrazine
- Phthalates
- Perchlorate
- Fire retardants
- Lead
- Mercury
- Arsenic
- Perfluorinated chemicals (PFCs)
- Organophosphate pesticides
- Glycol ethers
Early research by Tyrone Hayes, an integrative biologist at the University of California, Berkeley, hypothesized that atrazine turned on an enzyme (aromatase) that caused testosterone to be converted into estrogen. If you’re a male, this means that you won’t make sperm, but you will make estrogen, even though you shouldn’t.
According to Hayes and colleagues in research published in Nature in 2002, exposure to water-borne atrazine contamination led to “gonadal abnormalities such as retarded development and hermaphroditism” in 10 percent to 92 percent of male wild leopard frogs. Hayes published another study in 2010 in Proceedings of the National Academy of Sciences (PNAS), which had similar findings.[17]
Avoiding EDCs
Plastic is indeed ubiquitous.- Avoid plastic containers and plastic wrap for food. Store food and drinks in glass containers instead.
- Avoid plastic children’s toys. Use toys made of natural substances, such as wood and organic materials.
- Read labels on your cosmetics and avoid those containing phthalates.
- Avoid products labeled with “fragrance,” including air fresheners, as this catch-all term may include phthalates commonly used to stabilize the scent and extend the life of the product.
- Look for PVC-free products, including children’s lunch boxes, backpacks and storage containers.
- Do not microwave food in plastic containers or covered in plastic wrap.
- Frequently vacuum and dust rooms with vinyl blinds, wallpaper, flooring and furniture that may contain phthalates as the chemical collects in dust and is easily ingested by children.
- Eat mostly fresh, raw whole foods and avoid the food packaging that is often a source of phthalates.
- Use glass baby bottles instead of plastic. Breastfeed exclusively for the first year, if you can, to avoid plastic nipples and bottles altogether.
- Remove your fruit and vegetables from plastic bags immediately after coming home from the grocery store and wash before storing them; alternatively, use cloth bags to bring home your produce.
- Cash register receipts are heat printed and often contain BPA. Handle the receipt as little as possible and ask the store to switch to BPA-free receipts.
- Use natural cleaning products or make your own.
- Replace feminine hygiene products with safer alternatives.
- Avoid fabric softeners and dryer sheets; make your own to reduce static cling.
- Check your home’s tap water for contaminants and filter the water if necessary.
- Teach your children not to drink from the garden hose, as many contain plasticizers such as phthalates.
- Use reusable shopping bags for groceries.
- Take your own non-plastic leftovers container to restaurants. Avoid disposable utensils and straws.
- Bring your own mug for coffee and bring drinking water from home in glass water bottles instead of buying bottled water.
- Consider switching to bamboo toothbrushes and brushing your teeth with coconut oil and baking soda to avoid plastic toothpaste tubes.
