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Category: Toxic Tuesdays

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Toxic Tuesdays

Transgenerational Toxicity

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Transgenerational Toxicity

While getting cancer, liver disease or central nervous system damage is often associated with exposure to toxic chemicals, one of the most sensitive targets of toxic chemicals is the reproductive system. This has long been recognized for over 50 years (1, 2, 3). In recent years however, research has shown that toxic chemicals can not only directly affect the reproductive system of both women and men, but that these effects can be passed on to the next generation and can even skip a generation. The impact of toxic chemicals on children with no direct exposure to these chemicals is known as a transgenerational effect.

A recent review paper reported that research on chemical toxicity, early life nutrition, smoking and radiation found evidence of harm even in offspring with no direct exposure to specific contaminants. This paper pointed to groundbreaking research at Washington State University that helped establish the principle of transgenerational toxicity by showing that the effects of toxic chemicals can extend even to the third generation of offspring. Other review papers have found a growing body of evidence from epidemiological studies that suggests that environmental exposures early in development have a role in susceptibility to disease in later life and that some of these effects seem to be passed on through subsequent generations (6, 7).

One important study that made this clear was a follow-up study on the residents of Love Canal in Niagara Falls, NY. This study, conducted by the New York State Department of Health (DOH), found that maternal exposure to chemicals from the Love Canal landfill was associated with an elevated risk of bearing a child with an adverse reproductive outcome. The researchers found that women who lived in the designated emergency zone while pregnant prior to the time of evacuation had a higher risk of having a preterm birth compared to women from other regions of the state. This effect was statistically significant.

There was also a greater than expected frequency of congenital malformations among Love Canal boys born from 1983 to 1996. These birth defects occurred in infants born to mothers who previously lived at Love Canal. The rate of these birth defects was about 50% higher than in boys born to mothers who lived in upstate NY. In addition, the ratio of male to female births was lower for children conceived at Love Canal. Lastly, women exposed as children had an increased risk of giving birth to a low weight baby.

These findings are consistent with the initial findings at Love Canal that led to the evacuation of the community in 1978 and 1980. The initial findings identified lower birth weight and increased congenital birth defects in infants, but were limited in defining the risk of adverse pregnancy outcomes because of small sample sizes.

This study is extraordinary because it looked at the reproductive outcomes of women after their exposure had stopped compared to other studies which typically evaluate health effects at the time when exposures were ongoing. In some cases, exposures to Love Canal chemicals occurred only when the women were children! These remarkable findings point out the subtle impact of exposure to toxic chemicals. They are a red flag for health concerns – especially for women of child bearing age – at other contaminated sites across the country. This study also highlights how little we really know about low level exposures to toxic chemicals.

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Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Polybrominated diphenyl ethers (PCBEs)

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Polybrominated Diphenyl Ethers (PBDE)

Polybrominated Diphenyl Ethers (PBDE) are chemicals that are flame retardants – meaning they are added to different materials to make them less susceptible to fires. PBDEs are found in various everyday materials, such as furniture padding, computers, rugs, and electrical wires. They are a synthetic (not naturally found in the environment) subset of the organobromine compounds, chemicals where a carbon molecule is bonded to a bromine molecule. There are 209 different forms of PBDEs, which vary based on what the carbon-bromine structure looks like.

PBDEs were discovered in the 1970s, and since then, several of them have been phased out of production (PentaBDE and OctaBDE), but other versions (such as DecaBDE) are still being manufactured. While some states, such as California and Washington, have banned specific forms of PBDEs from production, there is no national restriction on the production of this chemical as of 2023. It’s also important to note that even for PBDEs that have been banned or phased out of production, the waste from production and manufacturing remains in the environment and causes harm.

The lack of national attention to this class of chemicals is concerning because of the mounting evidence that PBDEs have negative impacts on human health. For example, these chemicals are thought to be endocrine-disrupting. The endocrine system, which oversees the regulation of hormones, is vital to human health. When this system is damaged, it can cause various adverse health effects, such as cancer, reproductive damage, and neurological damage. A case-control study found that exposure to PBDEs was associated with an increased risk of breast cancer among post-menopausal women. Another study found that the BDE-28 compound was associated with an increased risk of papillary thyroid cancer. As for reproductive health, a study on infants reported that pregnancies that had PBDE chemicals in the umbilical cords, those infants were more likely to have lower birth weights. And a chemical that causes fetal abnormalities is called a teratogen, although PBDE does not carry this classification by the Environmental Protection Agency. Evidence of neurological damage has also been in animal studies, where PBDE was found to cause neurotoxic effects on memory, attention, and leaning ability.

Exposure to PBDEs during pregnancy is only one route of exposure to this chemical. Because PBDEs decompose slowly in the environment, they bioaccumulate and build up in the food chain. Fish and other marine life are especially prone to bioaccumulation. Thus, PBDE contamination could be of concern for people who consume a lot of seafood or rely on it as their primary protein source. Another way that people can be exposed to the chemicals is through water. PBDE waste can seep through the ground and contaminate the groundwater sources. Another exposure route, which accounts for an estimated 80% to 90% of exposure for the population, is inhaling contaminated dust particles. For example, PBDE can be found in the dust that accumulates in homes. One study found that individuals who had higher levels of PBDE in the dust at their houses had higher levels of the chemical in their blood serum levels.

PBDEs are considered persistent organic pollutants (POP), and many communities are fighting against this contamination in their backyards. For example, the Alaska Community Action on Toxins (ACAT) has been advocating for years to ban the use of PBDEs in the state. Another group that has been advocating for the ban on PBDEs are first responders, specifically fire-fighter organizations. When blood samples were taken from firefighters, they had brominated dioxins and furans in their bloodstreams. Fire fighters are more exposed to these chemicals because when a house fire occurs, all of the products that have PBDEs in them, such as furniture upholstery, burn up and release these toxic chemicals into the air that the first responders breathe in.

Learn about more toxics

Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Isobutylene

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Isobutylene

Isobutylene is a colorless gas that comes from natural gas. Its highly reactive nature makes it useful in the synthesis of many products including gasoline, rubber, plastics, resins, and other chemicals. Little toxicity information is known about isobutylene, and no occupational exposure limits are established, but exposure can cause irritation, headache, dizziness, and fatigue. The most dangerous feature of isobutylene is that it has a flash point of -80°C, meaning that above this temperature, it can ignite. As isobutylene is often in the presence of other flammable chemicals, isobutylene ignition can cause large explosions.

On February 3rd, 2023 a Norfolk Southern freight train derailed in East Palestine, Ohio. Twenty of the derailed cars contained hazardous chemicals, including isobutylene. Some cars released these chemicals into the surrounding air, soil, and water. On February 6th, Norfolk Southern made the decision to conduct a controlled burn of some of the remaining chemicals. Nearby residents were evacuated because of the health hazard of inhaling the smoke fumes. In addition to the fumes, release of chemicals into the surrounding environment could cause serious health problems. The Ohio Department of Natural Resources found that over seven miles of stream were affected by the chemical spill and thousands of fish died, raising concerns about dangers to residents in a large radius surrounding the spill. EPA ordered Norfolk Southern to identify and clean up contaminated soil and water. However, secrecy surrounding the scale of the accident and a reluctance to test thoroughly for all chemicals of concern has frustrated residents. EPA must prioritize the health of East Palestine residents and work transparently with them to identify and remediate the effects of this train derailment, chemical spill, and fire.

Learn about more toxics

Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Epigenetic Toxicity

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Epigenetic Toxicity

The way scientists think about how chemicals cause their toxic effects is changing. Recent scientific research tells us that the traditional notion of how chemicals act is being replaced by a better understanding of the actual features of exposures that influence how chemicals express their adverse effects in people. These features include the timing and vulnerability of exposures, exposures to mixtures, effects at low doses and genetic alterations called epigenetics.

It wasn’t too long ago that scientists believed that the DNA in our cells was set for life, that our genes would be passed on from one generation to the next, and that it would take generations to change our genetic makeup. This is no longer the case.

A new research area, called epigenetics, is perhaps the fastest growing field in toxicology and it is changing the way we think about chemical exposures and the risks they pose. Epigenetics is the study of changes in DNA expression (the process of converting the instructions in DNA into a final product, such as blue eyes or brown hair) that are independent of the DNA sequence itself.

Researchers are learning is that the “packaging” of the DNA is just as important as a person’s genetic make-up in determining a person’s observable traits, such as eye color, or their susceptibility to diseases such as adult on-set diabetes or lupus.

We are learning that the environment is a critical factor in the control of these packaging processes. We may be born with our genes, but epigenetic changes can occur because of environmental influences and exposures during development and throughout life. These influences include reactions to the chemicals in the food we eat, the air we breathe, the water we drink, and they appear to contribute to the development of cancer and other diseases.

Researchers have found that the genome, which is a person’s complete set of DNA, responds to toxic chemicals in the environment that a person is exposed to. It can lead to changes in gene expression, not by mutating the genes, but by sending subtle signals that stops gene activity or turns them on at the wrong times. Researchers believe that the genome has evolved from adapting to stressful survival situations to becoming more vulnerable to adverse environmental exposures, which leads to direct changes in people’s health based on how they respond to toxic chemicals in their environment. Linda Birnbaum, the former director of the National Institute of Environmental Health Sciences and the National Toxicology Program, put it this way: exposure to gene-altering substances, particularly in the womb and shortly after birth, “can lead to increased susceptibility to disease. The susceptibility persists long after the exposure is gone, even decades later. Glands, organs, systems can be permanently altered.”

This growing field of epigenetic toxicity may explain the long-term effects of chemical substances and the predisposition to disease that some people have due to environmental factors including exposure to chemicals. Epigenetics may also help to explain why certain people develop diseases and others do not, or why the person who smoked for 30 years never developed lung cancer.

There is still much to learn, but an early lesson to take away from this emerging science is that we need to rethink our traditional ideas of how chemicals affect our health. This is especially true since regulators and public health scientists who make decisions about safe levels of exposure to toxic chemicals are not considering epigenetic toxicity in their evaluations and are missing a critically important piece of the toxic chemical exposure puzzle. This may help explain why government is constantly telling people that the testing that has been done shows no cause for concern, while the people who have been exposed have symptoms and illnesses with no explanation for why they are sick.  

For more information on epigenetic toxicity, see these resources:

1. https://www.healthandenvironment.org/environmental-health/social-context/gene-environment-interactions

2. https://www.sciencedirect.com/science/article/pii/S0278691517305240

Learn about more toxics

Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Hydrofracking: Radiation Risk

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Hydrofracking: Radiation Risks

Hydraulic fracturing, or hydrofracking, is a process for accessing gas and oil deep within the earth. The process involves creating a well and drilling about one mile deep into the ground. Once it has been dug deep enough, cement is poured into the opening around a steel pipe to create a barrier between the fracking process and underground water sources. Then the drilling continues deeper into the earth, this time at an angle until it becomes horizontal. The length of that horizontal drilling can last up to three miles in length. Next, more cement is poured around the hole to create a barrier with the surrounding environment. Then a perforating gun is sent down the well into the horizontal section. There, it punctures the bedrock, creating multiple cracks that are 30 inches deep.

These cracks, or fissures, are created so that water, sand, and chemicals can be sent down into those newly made cracks. The water mixture causes further fracturing, like giant tree branches, in the bedrock that goes deep into the ground and releases oil and gas. The resource-intensive process can use up to 9.7 million gallons of water per one well. In addition, the wastewater that comes back from this process is radioactive and full of toxic chemicals that are hazardous to human health.

All that water then becomes unusable because of the naturally occurring radioactivity brought up from the ground with the waste. The health effects of the radioactive wastewater on humans are vast. The radioactivity is caused by the “naturally-occurring radionuclides” that are made up of uranium, thorium, and radium. These elements are hazardous to human health and can cause adverse health effects and even death with exposure to high levels, or concentrations, of the chemicals in the fracking water. Other than the radioactive chemicals found in fracking water, the industry also mixes over 1000 other chemicals into the water. These can include, but are not limited to, lead, PFAS (forever chemicals), ammonia, hormone disrupting chemicals, diesel, benzene and diesel. Exposure to these chemicals in the fracking wastewater can cause cancers, such as leukemia, hematologic (blood), urinary, and thyroid cancers. Exposure can also cause developmental health issues in children and neuromotor skill impairment. Heart disease is another area of concern, with communities close to hydrofracking sites having significantly higher heart attack rates.

Currently, most of the wastewater is stored in underground wells, but this storage solution can seep into the water supply in a variety of ways, as discussed in a peer-reviewed article published by Environmental Health Perspectives. Radioactive fracking wastewater can end up in so many different areas, from drinking water to consumer items. The reason why this is allowed has to do with the Safe Drinking Water Act of 2005 and the creation of the Halliburton Loophole. The loophole prevented the Environmental Protection Agency (EPA) from regulating the fracking industry or its wastewater. That means radioactive wastewater can end up in drinking water, but the agency cannot confront the company responsible.

Despite claims from fracking companies that the fracking-contaminated water is appropriately handled, radioactive wastewater finds its way back into the environment. The fracking wastewater can even be found in store-bought items. For example, the product AquaSalina is a de-icer that is sold in stores such as Home Depot and Lowe’s and contains the harmful chemicals. This product is available for public purchase and was even used by the state of Ohio. In 2019 alone, the Ohio Department of Transportation used a million gallons of the product. Outcry and protests from the impacted communities and environmental groups lasted for years until the state of Ohio agreed to ban the use of the product on their roads.

How can you take action on this issue? Contact your Congressional representatives today to let them know you support the reintroduction of H.R.2133, the FRESHER Act of 2021. The proposed bill would give the EPA the power to control wastewater discharge from oil and gas operations – meaning fracking wastewater would have regulation at the federal level.

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Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Vinyl Chloride

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Vinyl Chloride

Vinyl chloride is a chemical belonging to the family of compounds called organochlorides, which include other highly toxic chemicals including trichloroethane and the infamous pesticide DDT. Vinyl chloride is a man-made chemical that presents itself as a colorless and highly flammable gas under standard temperatures and pressures. This chemical used to have numerous industrial applications including as an aerosol propellant and refrigerant but concerns over its toxicity have relegated its use to the manufacture of polyvinyl chloride (PVC). Vinyl chloride is also created as a byproduct of the combustion of tobacco.

Exposure to high levels of vinyl chloride is extremely hazardous and can cause death. Inhalation of even small quantities of vinyl chloride has been observed to cause dizziness, a feeling of inebriation, and even loss of consciousness. The effects of prolonged exposure to vinyl chloride include lung irritation, breathing complications (especially for people with asthma), central nervous system problems, and cancer. Vinyl chloride is classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) and is significantly associated with multiple forms of liver cancer, brain and lung cancers, lymphoma and leukemia.

Exposure to vinyl chloride occurs primarily in occupational settings – in PVC and vinyl chloride factories – or near landfills where other organochloride compounds accumulate and ultimately break down into vinyl chloride.

Recently, vinyl chloride has been in the news since the train derailment in East Palestine, Ohio spilled over 1 million pounds of this chemical into the surrounding environment. Authorities handled the spill by burning the vinyl chloride to prevent an explosion (remember that vinyl chloride is extremely flammable), but by doing so they released dioxins – chemicals that are created from the combustion of vinyl chloride and other organochlorides. These dioxins (chemicals we wrote about in last month’s Toxic Tuesday) are extremely toxic and are linked to cancer, type 2 diabetes, heart disease, infertility in adults and impairment of the immune system.

CHEJ was asked to help the community in East Palestine and our Science Director, Stephen Lester, recently participated in an expert panel where he noted the improper handling of the vinyl chloride spill. CHEJ will continue helping the community in East Palestine through our community organizing training and our technical assistance capacity.

Learn about more toxics

Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

From Risk Assessment to Presumption

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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From Risk Assessment to Presumption

The last several issues of this series in Toxic Tuesday have addressed the difficulty in interpreting health risks when people are exposed to toxic chemicals. The last issue focused on the failure of the risk assessment approach to address these difficulties and the many critical limitations which make it inadequate and inappropriate for assessing public health risks. 

Despite these limitations, the government still relies on the risk assessment model as the “go-to” method to determine if the health problems people are suffering are due to exposures occurring or suspected of occurring in a community. Risk assessment fails to answer the basic question that people ask when exposed to toxic chemicals: How will my health, or the health of my children or family, be affected by these chemicals?

What we have seen over the years is that risk assessment cannot answer this question, no matter how well done or how much context is provided to help reduce misuse and misunderstanding. People exposed to toxic chemicals live for years with their exposures as scientists do health studies, health assessments, evaluate data on exposures and try to estimate risks. In most cases, people are told that the risk assessment shows that the level of toxic chemicals that people were exposed to are not likely (or some similar caveat) to cause any adverse health effects. Consequently, little, if any action is taken to protect communities exposed to toxic chemicals.

As part of CHEJ’s Unequal Response Unequal Protection campaign, we have been working with community leaders and environmental health scientists to develop a new approach that centers community leadership to address the difficult questions about chemical exposures. Instead of trying to determine if the health problems reported in a community were directly caused by the specific exposures to toxic chemicals occurring in that community, we adopted the approach  used by the federal government when considering adverse health effects suffered by veterans, active military, first responders, 9/11 victims and others exposed to toxic chemicals while serving their country.

In these situations, the government recognized that critical scientific information linking exposures and health outcomes was missing or incomplete thus making it necessary to make “presumptions” about exposures leading to the health problems suffered by these groups. This recognition led to the government providing health care, treatment, compensation and other assistance needed due to exposure to toxic substances suffered while serving our country. In communities where people have been exposed to toxic chemicals through no fault of their own, the government would extend a similar application of the presumptive approach. 

The presumptive approach asks what scientific information is sufficient to take action to protect people exposed to toxic chemicals? We propose the following approach to answer this question.

  1. Using existing and newly generated environmental sampling results collected in the impacted area, government (or an expert team of scientists) would compile a list of toxic substances to which the community is exposed.
  1. An independent committee of environmental and public health experts would then review the literature and determine what adverse health effects/diseases are associated with the toxic chemical(s) identified. Exposure to a chemical will be presumed to cause an adverse health effect if the evidence linking the chemical and the health effect is at least as likely as not, based on the strength of the studies found. The diseases with a positive association to the toxic substances present in the community would be used to decide which diseases will be presumed to be associated with the chemicals identified in the community.

Based on results of this approach, appropriate action to safeguard the health of the community can be taken. This decision could include remedies to lessen exposures and lessen the risk of injury and the effects of exposure. They might also include evacuation, providing a clean water supply, closing a polluting facility or implementing new emissions limitations.

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2-Butanone

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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2-Butanone

2-Butanone is an industrial chemical that is also known as methyl ethyl ketone (MEK). It manifests itself as a colorless liquid under standard conditions, tends to evaporate into the air (volatize) quickly, and is quite flammable. 2-Butanone is manufactured in large amounts for use in paints, glues, and other finishes because of its properties as a strong solvent and because of how quickly it can evaporate. It is also released into the air from the combustion process of vehicles.

Exposure to 2-butanone causes severe irritation to the eyes, nose, throat, and skin at high concentrations. Nervous system effects such as headaches, nausea, and dizziness have also been reported. Chronic health effects, those that develop due to long-term exposure to small quantities, are much less well understood.

Damage to the peripheral nervous system has been documented in individuals who sniffed glue, with 2-butanone being a significant part of the volatizing chemicals from glues. Liver, kidney, and respiratory effects were also observed in detailed studies of 2-butanone exposure in animals, while birth defects and malformations were observed in one rat study.

Exposure to 2-butanone can happen from a number of sources. Landfills and other contaminated industrial sites or factories tend to be significant sources. Although 2-butanone tends to evaporate into the air in these sites, because it has strong solvent properties, it also tends to sift through the soil into groundwater. Once there, it can remain trapped for several weeks. Active landfills that receive constant streams of paints, glues and similar products; or factories that produce or utilize 2-butanone can become significant hubs for exposure. If 2-butanone finds its way into drinking water sources, it can create a major exposure problem given its ability to remain present in water for an extended period of time.

Although groundwater and, potentially, drinking water can be easily contaminated by 2-butanone near factories and landfills, there is no federal drinking water standard for it. Certain states have taken a more precautionary approach and established local drinking water limits. For instance, Massachusetts, New Hampshire, and Minnesota have all set a guidance level of 4 mg/L. This proactive decision to limit the quantity of this potentially dangerous chemical should be an example to other states and the federal government.

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Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Classic Toxicology No Longer Works

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Classic Toxicology No Longer Works

The dose makes the poison is the most basic principle of toxicology. The first chapter in every toxicology textbook discusses how the response to a poison depends on how much of the poison you are exposed to (often referred to as the “dose”). This principle assumes that chemicals act by overwhelming the body’s defenses at higher doses. It also assumes that at some lower dose, there is no harm or no effect.

But this basic principle may no longer hold true as what we know about exposures to toxic chemicals is changing. Some time ago, Linda Birnbaum, former director of the National Institute for Environmental Health Sciences, wrote an overview paper on the changing science in the field of environmental health. She wrote in this paper that the antiquated perception of how chemicals act is being replaced by a “better understanding of the actual characteristics of modern environmental chemicals.”

These characteristics include the timing and vulnerability of exposure, exposures to mixtures, effects at low doses, and genetic alterations called “epigenetics.” Birnbaum addressed each of these frontiers of toxicology and discussed how each affects our understanding of the link between the environment and public health.  

It’s clear now that the body’s response to toxic chemicals is complex and not as predictable as classic toxicology would lead us to believe. Chemicals such as bisphenol A (BPA) and dioxin cause adverse effects at low doses, not predictable by classic toxicology. No longer can you safely assume that at some low dose there is no harm. Birnbaum makes it clear that within traditional toxicity “… [testing] of effects at some high doses are no longer adequate to [determining] the full spectrum of response from a given chemical.” What’s more, the effects observed at low doses may be different than those observed at higher doses.

We also now know that there are critical “windows of exposure” during development that determine effects – the same exposure at different times can result in different effects. There are also enhanced periods of vulnerability during prenatal development that “program” the bodies’ physiology leading to diseases in later life. According to Birnbaum, this phenomenon has been demonstrated for hypertension, coronary heart disease, and neurological and cognitive development.

Another advance in our understanding of toxicology comes from the field of epigenetics, or the study of changes in DNA expression that are independent of the DNA sequence itself. We now know that exposures to chemicals can alter the normal triggering mechanism that turns genes on or off that determines a person’s observable traits, such as blue eyes or susceptibility to diabetes or other illnesses. Says Birnbaum, “[We’re] born with our genes, but epigenetic changes occur because of environmental influences during development and throughout life.”

These advances in toxicology raise many questions about the adequacy of traditional methods of assessing the impact of exposure to chemicals like BPA or dioxin, not to mention mixtures. Regulatory agencies have not integrated this new science into the methods they use to assess public health risks and it’s likely to take some time before traditional toxicologists accept this new thinking and integrate it into their methods for assessing public health risks. In the meantime, recognize that some of what public health officials are telling you is antiquated and no longer applicable to the world we live in.

Learn about more toxics

Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Toxic Tuesdays

Polyvinyl Chloride

Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.

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Polyvinyl Chloride

Polyvinyl chloride, commonly known as “PVC” or “vinyl,” is the second largest commodity plastic in production in the world today, with an estimated 48.8 million tons produced worldwide in 2018. PVC is used in a wide range of products including pipes and tubing, school materials, product packaging, children’s toys, and several building materials.

PVC can safely be considered the worst plastic for our health and environment, as it releases dangerous chemicals that can cause cancer and other serious health effects from manufacture to disposal. The first problematic chemicals that can leach out of PVC products is phthalates. These are a group of industrial chemicals that are added to PVC to promote plasticity and flexibility. Because they are not chemically bound to PVC, these chemicals can leach out due to heat, pressure or simply time. Once they are out in the environment, they can enter our bodies and cause adverse health conditions such as hormone disruption, birth defects, infertility and asthma. Lead is another chemical that is commonly found in PVC. Lead exposure is especially dangerous for growing children, who can suffer from nervous system development problems and learning disabilities.

Aside from direct exposure to PVC, the manufacturing and disposal process of PVC can release harmful chemicals called dioxins. Dioxins are formed and released when PVC is burned (during disposal) or manufactured under high heat and pressure. They are a highly toxic group of chemicals that build up in the food chain, cause cancer and can harm the immune and reproductive systems. Their toxicity is of such concern that they have been targeted for global phase out by the Stockholm Convention on Persistent Organic Pollutants.

As mentioned previously, exposure to PVC through everyday consumer products can be significant. Children’s toys can be substantially bad offenders, although CHEJ’s PVC campaign of the late 2000s made a difference in removing a lot of PVC from the toy market. Other items that remain problematic are children’s backpacks, shower curtains, rain boots, raincoats, vinyl flooring and roofing, plastic food containers, and pet toys.

CHEJ helped develop a resolution from the American Public Health Association (APHA) – a policy statement that has the full backing of the organization – back in 2011. CHEJ was instrumental in convincing the APHA to endorse reducing PVC in facilities with vulnerable populations such as nursing homes and hospitals. This was a monumental statement from the premier public health organization in the country about the dangers of PVC.

Learn about more toxics

Benzidine

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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Pyrethrins

Pyrethrins are a class of naturally occurring compounds derived from chrysanthemum flowers. They have been

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