Endocrine-Disrupting Chemicals: Intersex is Rising, Sperm Counts Are Falling

 Endocrine-disrupting chemicals (EDCs) are those that are sufficiently similar to human hormones that they can fool the body’s hormone receptors into responding at an inappropriate time or trigger a response altogether inappropriate.  Encountering such chemicals is particularly risky if the occurrence is in the fetal stage where growth and development depend on hormonal surges at the correct time and with the correct intensity.  Body function depends critically on proper hormonal function, making encounters with these disrupting chemicals dangerous.   Consider this list provided by Wikipedia of health issues they can cause. 

“…[EDCs]are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause numerous adverse human health outcomes including, alterations in sperm quality and fertility, abnormalities in sex organs, endometriosis, early puberty, altered nervous system function, immune function, certain cancers, respiratory problems, metabolic issues, diabetes, obesity, cardiovascular problems, growth, neurological and learning disabilities, and more.”

One might hope that such chemicals, essentially being poisons, would be highly regulated and be restricted from use in common products.  Rather, the opposite is true.  Consider this range of products using EDCs provided by this source: ENDOCRINE DISRUPTERS: A REVIEW OF SOMESOURCES, EFFECTS, AND MECHANISMS OF ACTIONS ON BEHAVIOR AND NEUROENDOCRINESYSTEMS.

“Exposure in people is typically due to contamination of the food chain, inhalation of contaminated house dust, or occupational exposure. EDCs include pesticides and herbicides (such as diphenyl-dichloro-trichloroethane, DDT, or its metabolites), methoxychlor, biocides, heat stabilizers and chemical catalysts (such as tributyltin, TBT), plastic contaminants (e.g. bisphenol A, BPA), pharmaceuticals (i.e. diethylstilbestrol, DES; 17alpha-ethynilestradiol, EE2), or dietary components (such as phytoestrogens).”

The sources of EDCs of most interest here are pharmaceuticals and plastics.  Most of the pharmaceutical drugs we ingest end up exiting our bodies through our urine, thus entering our wastewater and passing into our water systems where they accumulate over time.  The concentrations in our lakes and rivers are great enough that they are being encountered in the bodies of ocean-dwelling fish. 

The plastics industry uses thousands of chemicals in producing its products, some of which are known to be endocrine disrupters.  Plastics break down readily by fragmentation.  Every time a fragment is formed chemicals are released with the fragments.  Drinking water from a plastic bottle introduces us to a hundred or more chemicals as well as plastic particulates.  Particularly insidious is the use of plastic bottles to feed our infants formula and giving them plastic nipples with which to ingest it.  Plastic is everywhere.  Plastic particulates are in the air we breathe, on the highest mountain tops, and in the deepest ocean depths.  There are so many particulates in our waters that a breeze over the surface brings plastic particulates for us to inhale.  If the particulates are small enough, they can pass through our lungs and into our blood stream.  Similarly, small particulates can enter our blood streams through our digestive systems.  Once in our blood, particles and the chemicals they leach can go anywhere in our bodies, including through the placenta of a pregnant woman into a fetus. 

The list provided above of adverse health outcomes from encounters with EDCs is headed by “alterations in sperm quality and fertility, abnormalities in sex organs.”  These are what we are concerned with here.  Intersex is not a well-recognized issue—yet.  Wikipedia provides this definition of the term.

“Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, ‘do not fit typical binary notions of male or female bodies’.” 

It has long been known that polluted waters were causing high incidences of intersex in fish populations.  Consider this article: Intersex Fish on the Rise in Northeastern U.S. Rivers.

“The USGS defines intersex conditions in fish as occurring ‘when exposure to chemicals disrupts the hormonal systems of an animal, leading to the presence of both male and female characteristics in an animal that should exhibit the characteristics of just one sex in its lifetime’.”

The effects can be extreme as the chemical pollution increases.

“…one of the latest trends spotted in the continental Midwest and some parts of New England, male smallmouth and largemouth bass developing eggs in their testes.”

"At one study site near Hershey, Pa., USGS researchers found 100 percent of male smallmouth collected had eggs.”

In at least one site, an entire population of fish had its sexual development corrupted.  How great a level of chemical pollution would cause similar results in humans? The NIH was sufficiently concerned that intersex in humans was increasing to issue this report: The Increasing Prevalence in Intersex Variation from Toxicological Dysregulation in Fetal Reproductive Tissue Differentiation and Development by Endocrine-Disrupting Chemicals.

“With the increasing incidence of intersex birth variations, urgency exists to better understand how chemicals in the environment are affecting fetal development. Identifying specific chemicals that pose the greatest risk during this critical window in genital development and quantifying the level at which they are capable of asserting their influence is an ongoing challenge for scientists.”

Male sperm counts have been falling for years.  This is not new information; what is new is the fact that sperm concentrations are becoming dangerously low.  Consider this article: How pollution is causing a male fertility crisis.  The author refers to Hagai Levine as an expert in this field.

“Seemingly small changes can have a powerful effect on these highly specialised cells, and especially, their ability to fertilise an egg. The crucial aspects for fertility are their ability to move efficiently (motility), their shape and size (morphology), and how many there are in a given quantity of semen (known as sperm count). They are the aspects that are examined when a man goes for a fertility check.”

“Sperm count, explains Levine, is closely linked to fertility chances. While a higher sperm count does not necessarily mean a higher probability of conception, below the 40 million/ml threshold the probability of conception drops off rapidly.”

We are approaching that threshold—rapidly!

“In 2022, Levine and his collaborators published a review of global trends in sperm count. It showed that sperm counts fell on average by 1.2% per year between 1973 to 2018, from 104 to 49 million/ml. From the year 2000, this rate of decline accelerated to more than 2.6% per year.”

The author also presents the work of Rebecca Blanchard, a veterinary teaching associate and researcher at the University of Nottingham, UK.  She noted that dogs share the environments of humans, encountering similar chemical environments from air, food, medications, and household plastics.

“Her research concentrated on chemicals found in plastics, fire retardants and common household items…  Her studies have revealed that these chemicals can disrupt our hormonal systems, and harm the fertility of both dogs and men.”

"’We found a reduction in sperm motility in both the human and the dog,’ says Blanchard. ‘There was also an increase in the amount of DNA fragmentation’."

“Sperm DNA fragmentation refers to damage or breaks in the genetic material of the sperm. This can have an impact beyond conception: as levels of DNA fragmentation increase, explains Blanchard, so do instances of early-term miscarriages.”

“The findings chime with other research showing the damage to fertility caused by chemicals found in plastics, household medications, in the food chain and in the air. It affects men as well as women and even babies. Black carbon, forever chemicals and phthalates have all been found to reach babies in utero.”

We are being affected by chemicals that can enter our bodies before we are born and while we live our lives.  As the concentrations of these chemicals in our environment rise ever higher, the deleterious effects become ever more prevalent.  If we wanted to ban the critical chemicals, could we do it? And could we do it before it became too late?  Current responses to such threats suggest we cannot.