Endocrine disruptors, also called hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds, are chemicals that can interfere with the body's hormonal systems. This interference can lead to many health problems, such as changes in sperm quality and fertility, issues with sex organs, endometriosis, early puberty, changes in the nervous or immune systems, certain cancers, breathing difficulties, metabolic problems, diabetes, obesity, heart issues, growth delays, learning disabilities, and other challenges. These chemicals are found in many household and industrial products. They can disrupt how the body makes, releases, carries, uses, or removes natural hormones that control development, behavior, fertility, and the body's balance.

Any system in the body that uses hormones can be affected by hormone disruptors. These chemicals may be linked to learning disabilities, severe attention deficit disorder, and problems with brain development.

There has been debate about endocrine disruptors. Some groups want regulators to quickly remove them from the market, while others believe more research is needed. Some endocrine disruptors have already been removed (such as a drug called diethylstilbestrol), but it is unclear if others currently on the market harm humans or wildlife at the levels they are exposed to. A 2012 report by the World Health Organization stated that even small amounts of exposure may cause health problems in people.

History

The term "endocrine disruptor" was created in 1991 during a meeting at the Wingspread Conference Center in Wisconsin. One of the first papers about this topic was written by Theo Colborn and others in 1993. It said that chemicals in the environment can harm the development of the endocrine system, and that effects from exposure during development are often long-lasting. While some people have questioned whether endocrine disruption is real, meetings between 1992 and 1999 led scientists to agree that endocrine disruptors pose a risk, especially for wildlife and humans.

The Endocrine Society published a scientific report that explained how endocrine disruptors affect "male and female reproduction, breast development and cancer, prostate cancer, brain and hormone functions, thyroid, metabolism and weight, and heart health." The report showed that studies on animals and humans support the idea that endocrine disruptors are a major public health concern. It also said it is hard to prove that endocrine disruptors cause human diseases and suggested using the precautionary principle, which means taking steps to protect health even if some risks are not fully understood. Another report discussed policy issues related to endocrine disruptors.

Endocrine disrupting compounds include many types of chemicals, such as medicines, pesticides, chemicals used in plastics and consumer products, industrial waste, pollutants, heavy metals, and some naturally occurring plant chemicals. Industrial chemicals like parabens, phenols, and phthalates are also strong endocrine disruptors. Some of these chemicals are widespread in the environment and can build up in living things over time. Others are long-lasting pollutants that can travel across borders and have been found in nearly every part of the world, even near the North Pole. Some chemicals break down quickly in the environment or in the human body and stay for only short periods. Health problems linked to endocrine disruptors include reproductive issues (such as lower fertility, birth defects in reproductive organs, imbalanced sex ratios, miscarriage, and menstrual problems), changes in hormone levels, early puberty, brain and behavior issues, weakened immune systems, and various cancers.

An example of the effects of exposure to hormonally active chemicals is the drug diethylstilbestrol (DES), a type of estrogen that was not an environmental pollutant. Before it was banned in the early 1970s, doctors gave DES to about five million pregnant women to prevent miscarriage, an unapproved use of the drug before 1947. Later, it was found that DES harmed the reproductive systems of children and caused vaginal cancer. However, the amounts of DES used in this case were much higher than those from typical environmental exposure, making it unclear how directly this example relates to the risks of endocrine disruptors.

Aquatic life exposed to endocrine disruptors in polluted water has shown lower levels of serotonin and more female characteristics.

In 2013, the World Health Organization (WHO) and the United Nations Environment Programme released a report, the most detailed study on endocrine disruptors to date. The report called for more research to fully understand the links between endocrine disruptors and health risks for humans and animals. The team noted major gaps in knowledge and recommended:

• Testing: Currently known endocrine disruptors are only a small part of the problem. Better testing methods are needed to find other possible endocrine disruptors, their sources, and how people and animals are exposed.
• Research: More scientific evidence is needed to understand how mixtures of endocrine disruptors affect humans and wildlife, especially from industrial waste.
• Reporting: Many sources of endocrine disruptors are unknown because there is not enough information about chemicals in products, materials, and goods.
• Collaboration: Sharing data between scientists and countries can help fill knowledge gaps, especially in developing countries and emerging economies.

Endocrine system

The endocrine system is found in most types of animals. This system includes glands that produce hormones and receptors that detect and respond to these hormones. Hormones move through the body in the bloodstream and act as chemical messengers. They connect with cells that have matching receptors on or inside their surfaces. When a hormone binds to a receptor, it is similar to how a key fits into a lock. The endocrine system controls changes in the body through slower processes, using hormones as messengers. It releases hormones in response to changes in the environment and to manage growth and reproduction. The changes caused by the endocrine system are biochemical, altering the inside and outside of cells to create long-term effects in the body. These systems work together to keep the body functioning properly throughout its life. Hormones like estrogens, androgens, and thyroid hormones are regulated by feedback systems, which help control how sensitive these glands are.

Hormones work in very tiny amounts, even as small as one part per billion. Exposure to low levels of foreign hormones or chemicals, such as bisphenol A, can disrupt the endocrine system. These chemicals may attach to receptors involved in other hormone-related processes. Since the body already has natural hormones in active amounts, even small amounts of foreign substances can interfere with the endocrine system’s normal function. This disruption can cause harm at much lower doses than typical toxicity, through a different process.

The timing of exposure is important. Many key stages of development happen in the womb, where the fertilized egg divides and forms all parts of a baby, including the brain. Disrupting hormone communication in the womb can lead to serious effects on the body’s structure and brain development. Depending on the stage of development, hormone interference can cause changes that are permanent and not seen in adults exposed to the same dose. Studies in animals have shown that exposure to chemicals that mimic or block hormones during critical times in the womb or shortly after birth can cause lasting effects into adulthood. Early disruption of thyroid function may lead to problems with sexual development, motor skills, and learning abilities.

Research on cells, lab animals, wildlife, and people accidentally exposed to chemicals shows that these substances can cause a wide range of effects on reproduction, development, growth, and behavior. While evidence of endocrine disruption in humans by pollutants is still limited, the science behind it is solid, and the possibility of such effects is real. Studies have focused on chemicals that mimic estrogen, testosterone, or thyroid hormones, but less is known about how other hormones might be affected.

Exposure to endocrine-disrupting chemicals has also been linked to changes in the immune system. Since immune activity is controlled by hormones, disrupting hormone signals can affect how the body produces immune-related proteins and how immune cells respond. These changes may lead to weaker immune responses and increased inflammation, including a higher risk of autoimmune diseases. Early-life exposure is especially concerning because interference during key developmental stages can cause long-term changes in immune function.

The connection between chemical exposure and health effects is complex. It is difficult to prove that a specific chemical causes a particular health problem, and adults exposed to these chemicals may not show symptoms. However, fetuses and embryos, whose growth is strongly controlled by the endocrine system, are more vulnerable to exposure and may develop lifelong health or reproductive issues. Exposure before birth can sometimes lead to permanent changes and adult diseases.

Some scientists are concerned that exposure to endocrine disruptors during pregnancy or early life may be linked to brain development problems, such as lower intelligence, ADHD, or autism. Certain cancers and reproductive issues in women have been connected to exposure to a chemical called diethylstilbestrol (DES) during pregnancy.

In a 2005 study, chemicals called phthalates found in the urine of pregnant women were linked to small but specific changes in the genitalia of their male babies, such as a shorter distance between the genitals and anus, incomplete descent of the testes, and smaller scrotum and penis. Industry experts questioned the study, and in 2008, only five studies on this topic had been done, with one researcher noting that it was unclear if these measurements were useful for understanding hormone effects. Today, it is clear that this measurement, called anogenital distance, indicates exposure to male hormones in the womb. Studies have found that this measurement is linked to the risk of prostate cancer later in life.

Effects on intrinsic hormones

Toxicology research shows that some endocrine disruptors focus on a specific hormone feature that helps hormones control how the body makes or breaks down its own hormones. Because endocrine disruptors can copy or block natural hormones, these chemicals work by interacting with nuclear receptors, the aryl hydrocarbon receptor, or membrane-bound receptors.

U-shaped dose-response curve

Most harmful substances, including endocrine disruptors, are said to follow a U-shaped dose-response curve. This means that very low and very high levels of exposure can cause more effects than mid-level exposure.

Endocrine-disrupting effects have been observed in animals exposed to chemical levels commonly found in the environment. For example, a widely used flame retardant called BDE-47 affects the reproductive system and thyroid gland of female rats at doses similar to those humans are exposed to.

Low concentrations of endocrine disruptors may also work together to cause greater harm in amphibians. However, it is unclear if this effect is related to the endocrine system.

A consensus statement from the Learning and Developmental Disabilities Initiative stated that "the effects of endocrine disruptors at very low doses cannot be predicted from studies using high doses. This challenges the traditional rule in toxicology that 'dose makes the poison.' Non-monotonic dose-response curves describe these unusual patterns."

It has been reported that tamoxifen and some phthalates have different (and harmful) effects on the body at low doses compared to high doses.

Routes of exposure

Food is a major way people come into contact with harmful chemicals. Eating food is believed to be the source of up to 90% of the amount of PCB and DDT in a person's body. In a study of 32 common food items from three grocery stores in Dallas, Texas, fish and other animal products were found to contain PBDE. These chemicals dissolve in fat, so they likely build up in the fatty parts of animals that humans eat. Some believe eating fish is a major way people get many environmental pollutants. Studies show that wild and farmed salmon from around the world have been found to contain many man-made chemicals. While pesticides are found in many foods, phthalates can also enter crops, vegetables, and fruits from polluted soil and plastic covers used in greenhouses.

Endocrine disruptors can cause changes in the body's hormones. Children and babies are more likely to be affected by these chemicals. Phthalates are used to make plastics last longer and can be found in water bottles and during all steps of dairy production. Drinking water from plastic bottles is a way people are exposed to endocrine disruptors. However, the risk to humans is not considered very high. Phytoestrogens are natural endocrine disruptors found in food. Soybeans contain a type of phytoestrogen called Geinstein. Studies in Turkey found that some types of eggs, like battery eggs, contain phthalates, and free-range eggs have traces of DDT, a banned pesticide.

Indoor air has become a major source of exposure to pollutants because of more household products with harmful chemicals and less ventilation in homes. People living in homes with wood floors treated in the 1960s with PCB-based finishes have higher levels of these chemicals in their bodies than most people. A study of house dust and dryer lint from 16 homes found high levels of all 22 types of PBDE chemicals tested. Recent research suggests that house dust, not food, may be the main source of PBDE in the body. One study estimated that eating house dust accounts for up to 82% of the PBDE in people's bodies.

Contaminated house dust is a major source of lead in young children's bodies. Babies and toddlers may eat more house dust than adults, leading to higher levels of pollutants in their bodies.

Consumer products are another way people are exposed to endocrine disruptors. A study compared 42 household cleaning and personal care products with 43 products labeled "chemical-free." The products contained 55 different chemicals, including parabens, which are linked to reproductive issues. Parabens were found in some "chemical-free" products, even in sunscreens that did not list them on labels. Vinyl products like shower curtains were found to contain more than 10% of a chemical called DEHP, which is linked to asthma and wheezing in children. Using multiple products, whether regular or "chemical-free," increases the risk of exposure to endocrine disruptors. For example, using certain cleaners, laundry detergent, and personal care products could expose someone to at least 19 different chemicals.

A study of mid-pregnancy in Old Order Mennonite women found lower levels of endocrine-disrupting chemicals in their bodies compared to the general population. Mennonites eat mostly fresh, unprocessed food, avoid pesticides, and use few cosmetics. One woman who used hairspray and perfume had high levels of a chemical called monoethyl phthalate, while others had levels too low to detect. Women who were in a car or truck within 48 hours of giving a urine sample had higher levels of another chemical, diethylhexyl phthalate, which is used in car interiors.

Recent research has focused on clothing as a source of exposure to endocrine disruptors. Greenpeace reported finding phthalates in 33 out of 35 printed clothing items in a 2013 study. A t-shirt from Primark Germany had high levels of DEHP, and a baby one-piece from American Apparel had high levels of DINP. PFCs were found in swimwear and waterproof clothing, and NPEs were common in most clothing. A 2014 study by Greenpeace Germany found high levels of phthalates in athletic gear, including a t-shirt with 15% phthalates and gloves with 6% phthalates. The study also found PFAS, nonoxynols, and dimethylformamide in shoes and boots.

A 2019 study by Li et al. found that skin contact, including through clothing, is the main way infants are exposed to phthalates. Washing clothes did not remove all phthalates. DEHP and DBP were found in high amounts in infant clothing. A 2019 study by Tang et al. found all 15 types of phthalates tested in preschoolers' clothing. Levels varied by garment type, fabric, and color, but wearing certain combinations, like trousers, long-sleeved shirts, and socks together, increased reproductive risks.

A review of 120 studies from 2014 to 2023 found that screen printing ink, vinyl patches, and synthetic leather can contain 30–60% phthalates. Waterproof items like infant mattress covers also had high levels of these chemicals. Manufacturers often replace more regulated chemicals like DEHP with newer ones that may not be as strictly controlled.

Chemicals added to plastics during manufacturing can leak into the environment after the plastic is thrown away. These chemicals can enter water, soil, and air from plastics in oceans, landfills, and products like food containers, toys, and personal care items. They can build up in the environment over time.

Types

Everyone comes into contact with chemicals that mimic estrogen in their daily lives. These chemicals, called endocrine disruptors, are found in small amounts in thousands of products. Common chemicals found in people include DDT, polychlorinated biphenyls (PCBs), bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), and many types of phthalates. Almost all plastic products, even those labeled "BPA-free," have been found to release endocrine-disrupting chemicals. A 2011 study showed that some BPA-free products released more endocrine-active chemicals than products containing BPA. Other endocrine disruptors include phytoestrogens, which are plant-based compounds that act like estrogen.

Xenoestrogens are a type of xenohormone that imitates estrogen. Synthetic xenoestrogens include industrial chemicals like PCBs, BPA, and phthalates, which can affect living organisms.

Alkylphenols are a type of xenoestrogen. The European Union has banned certain uses of nonylphenols because they are toxic, last a long time in the environment, and can build up in living things. The United States Environmental Protection Agency (EPA) has taken a slower approach to ensure actions are based on scientific evidence.

Long-chain alkylphenols are used in making detergents, fuels, polymers, and phenolic resins. They are also used to create fragrances, thermoplastic elastomers, antioxidants, oil field chemicals, and fire retardants. These chemicals are found in tires, adhesives, coatings, carbonless copy paper, and high-performance rubber products. They have been used in industry for over 40 years.

Some alkylphenols are byproducts of nonionic detergents. Nonylphenol is a low-level endocrine disruptor because it can mimic estrogen.

Bisphenol A (BPA) is found in plastic bottles, food containers, dental materials, and the linings of metal cans for food and infant formula. People are also exposed to BPA through receipt paper used in stores and restaurants, which is often coated with BPA-containing clay for printing.

BPA is known to disrupt the endocrine system. Studies on laboratory animals show that exposure to low levels of BPA can increase the risk of diabetes, breast and prostate cancers, lower sperm counts, reproductive problems, early puberty, obesity, and neurological issues. In the United States, studies found that BPA levels in the urine of healthy women were not linked to pregnancy timing, but other research in fertility centers showed BPA exposure may be connected to lower ovarian reserves. Many women undergoing in vitro fertilization (IVF) had high BPA levels in their urine. Women who had miscarriages had higher BPA levels compared to those who had successful pregnancies. These findings suggest BPA may affect ovarian function and early conception. One study found Asian women had higher oocyte maturity rates but lower BPA levels. Early life stages appear most sensitive to BPA’s effects, and some studies link prenatal exposure to later physical and neurological challenges. Regulatory agencies have set safety levels for BPA, but these levels are being reviewed due to new research. A 2011 study found BPA in 96% of pregnant women in the U.S. In 2010, the World Health Organization said no new regulations limiting BPA use were needed at that time.

In 2008, the U.S. FDA said BPA was safe based on scientific evidence. However, the FDA’s advisory Science Board said the assessment had flaws and did not prove BPA was safe for infants. In 2010, the FDA reported concerns about BPA’s effects on the brains and behavior of fetuses, infants, and young children. In 2012, the FDA banned BPA in baby bottles, but the Environmental Working Group called the ban "cosmetic." They argued that banning BPA in infant formula, food, and beverage cans would better protect people. The Natural Resources Defense Council said the FDA should ban BPA from all food packaging. A FDA spokesperson said the ban was not based on safety concerns and that BPA is safe for food-related products.

A program by the National Institute of Environmental Health Sciences (NIEHS), the National Toxicology Program (NTP), and the FDA (named CLARITY-BPA) found no effects from long-term BPA exposure in rats. The FDA continues to say currently approved uses of BPA are safe for consumers.

The Environmental Protection Agency (EPA) set a reference dose for BPA at 50 micrograms per kilogram of body weight per day for mammals. Studies show even lower doses can affect reproductive systems in males and females.

Bisphenol S (BPS) and Bisphenol F (BPF) are similar to BPA. They are found in thermal receipts, plastics, and household dust. Traces of BPS have also been found in personal care products. BPS is now used in BPA-free items because of BPA bans. However, BPS and BPF can also disrupt the endocrine system like BPA.

Dichlorodiphenyltrichloroethane (DDT) was first used as a pesticide in 1936 to control Colorado potato beetles on crops. Its use expanded to fight diseases like malaria, typhus, dysentery, and typhoid fever by targeting mosquitoes, lice, and houseflies. Before World War II, pyrethrum, a natural insecticide from Japanese flowers, was used. Japan stopped exporting pyrethrum during the war, leading to the search for alternatives. DDT was given to soldiers to prevent typhus outbreaks by dusting beds, tents, and barracks.

After World War II, DDT was approved for general use. It helped increase crop yields and reduce malaria cases worldwide. However, most countries later banned its agricultural use due to environmental harm, while its use for malaria control is still allowed under the Stockholm Convention on Persistent Organic Pollutants.

As early as 1946, scientists noticed DDT’s harmful effects on birds, beneficial insects, fish, and marine life. One famous example was the decline of bird populations, such as eagles and birds of prey, due to DDT’s impact on their reproductive systems.

Temporal trends of body burden

Since DDT and PCB were banned, the average amounts of these chemicals in human bodies have decreased. After being banned in 1972, the amount of PCB in people's bodies in 2009 was 1/100th of what it was in the early 1980s. However, studies of breast milk samples from Europe show that levels of PBDE are increasing. Research comparing PBDE levels in breast milk from Europe, Canada, and the United States found that North American women have 40 times more PBDE than Swedish women. In North America, PBDE levels are increasing by about twice every 2 to 6 years. Some scientists have suggested that the gradual decrease in average body temperature since the start of the industrial revolution might be caused by changes in thyroid hormone signals.

Animal models

Endocrine disruptors can affect important body systems, such as metabolism, reproduction, and the nervous system. Scientists use animal models to study the risks of these chemicals. Common animals used in these studies include mice, fish egg yolks, and frogs.

Genetically engineered mice are used to study genetic differences in populations. One type of population is called the multi-parent population, which includes two types: collaborative cross (CC) and diversity outbred (DO) strains.

These populations are made from eight different mouse strains. Some of these strains come from wild mice (which have a lot of genetic diversity), and others are bred in labs for research. Each genetically different group is used to study how endocrine-disrupting chemicals (EDCs) affect the body.

The CC population includes 83 inbred mouse strains. These strains were created over many generations in labs from the original eight strains. DO mice share the same genetic information as CC mice, but there are two key differences: each DO mouse is unique, allowing scientists to study many individuals in one experiment, and DO mice cannot be reproduced.

Scientists breed mice by adding genes from other organisms to create transgenic lines. These lines are made using techniques like CRISPR. This process helps create thousands of mouse lines for research.

Genes can be changed in specific cells if the right conditions are met. For EDC research, scientists use humanized mouse models, which have human-like genes. They also use gene knockout lines, where certain genes are removed, to study how EDCs affect body functions. Transgenic rodents are used for similar studies, but they take longer to create and are more expensive.

Scientists use rodent models to study how EDCs might affect behaviors. Prairie and pine voles are useful for this because they form long-term pair bonds, similar to humans. This makes them a good model for studying how EDCs affect human social behaviors.

The endocrine systems in mammals and fish are similar. Because of this, scientists use zebrafish (Danio rerio) in research. Zebrafish embryos are transparent and very small (larvae are less than a few millimeters long). They have simple ways of being affected by EDCs and share similar body systems, senses, and signaling methods with mammals. Scientists also use zebrafish because their genome is fully mapped, and many transgenic lines are available for breeding. Zebrafish and mammals share many genetic similarities, with about 80% of human genes also found in zebrafish.

Directions of research

Research on endocrine disruptors faces five challenges that require special study designs and detailed scientific methods:

• Dissociation of space: Even though disruptors may work through the same hormone receptors, their effects can also happen in other ways, such as through proteins that carry hormones, enzymes that change hormone activity, how hormones break down, or changes in how the body balances hormone levels.
• Dissociation of time: Harmful effects might occur during early stages of life, such as in embryos or fetuses, but the results could appear much later, even in future generations.
• Dissociation of substance: When multiple disruptors are present, their combined effects can be different from the effects of each substance alone, sometimes in complex ways.
• Dissociation of dose: The relationship between the amount of a disruptor and its effects is not always straightforward. Sometimes, small or medium amounts can cause stronger effects than large amounts.
• Dissociation of sex: The effects of disruptors can differ depending on whether the embryo or fetus is female or male.

Legal approach

In the United States, many laws help control chemicals that can harm the body's hormone system. These laws include the Toxic Substances Control Act, the Food Quality Protection Act, the Food, Drug and Cosmetic Act, the Clean Water Act, the Safe Drinking Water Act, and the Clean Air Act.

The U.S. Congress has made changes to how medicines and chemicals are tested and regulated. The Food Quality Protection Act of 1996 and the Safe Drinking Water Act of 1996 required the Environmental Protection Agency (EPA) to create a program to test chemicals for effects similar to hormones in humans.

In 1998, the EPA started the Endocrine Disruptor Screening Program. This program aimed to test more than 85,000 chemicals used in products. The Food Quality Protection Act required the EPA to test pesticides for estrogen-like effects, but it also allowed testing of other chemicals and hormone-related effects. Based on advice from experts, the EPA expanded the program to test chemicals for effects on male hormones, the thyroid, and wildlife.

The program prioritizes chemicals based on how they are used, how much is produced, their structure, and their toxicity. Testing uses lab experiments, such as checking if chemicals interact with hormone receptors, and studies on animals, like observing frog development or rodent growth. Full testing includes examining effects in animals like rats, frogs, fish, birds, and invertebrates. Animal testing is needed for accurate results, but some groups oppose it. Human testing would also be needed to confirm effects in people, though this is also opposed.

The EPA faced delays in starting the program and finally began testing suspected endocrine disruptors in 2007, 11 years after the program was announced. Critics said the testing methods were not well designed and that chemical companies influenced the process. In 2005, the EPA reviewed the program and found its goals were appropriate, though the review happened before the final testing plan was announced. The EPA still struggles to create a reliable testing program.

By 2016, the EPA had tested 1,800 chemicals for estrogen-related effects.

In 2013, the European Union proposed banning some pesticides containing endocrine disruptors. However, U.S. trade negotiators asked the EU to remove these rules, saying regulations should be based on risk. The European Commission planned to set rules by 2013 to identify endocrine disruptors in products like disinfectants, pesticides, and personal care items linked to health issues. But delays led Sweden to threaten legal action, blaming pressure from the chemical industry.

Sweden’s environment minister said hormone disruptors are a growing problem, with examples like fish with both male and female traits and health effects on children. In 2014, a report estimated that endocrine disruptors cost EU health systems between 59 million and 1.18 billion euros yearly, though this number only reflects a small part of related health issues.

In 2020, the EU released a plan to make the chemical industry safer by reducing harmful chemicals like xenohormones.

Environmental and human body cleanup

There is evidence that when a pollutant is no longer used or its use is limited, the amount of that pollutant in the human body decreases. Large-scale monitoring programs have helped identify the most common pollutants found in people. The first step in reducing the amount of these pollutants in the body is to stop producing or gradually reduce their use.

The second step is to raise awareness about foods that may contain high levels of pollutants and to label them clearly. This approach has been successful before, such as when pregnant and nursing women are advised to avoid eating seafood that contains high levels of mercury.

The biggest challenge is learning how to remove these pollutants from the environment and deciding where to focus cleanup efforts. Even pollutants that are no longer produced can remain in the environment and build up in the food chain. Understanding how these chemicals move through ecosystems is important for finding ways to remove them. Global efforts have led to labeling the most common persistent organic pollutants (POPs) found in the environment, using chemicals like insecticides. The twelve main POPs have been grouped together to make information easier for the public. This has helped countries work together to test and reduce the use of these chemicals. By reducing these chemicals in the environment, their spread into food sources that supply the U.S. population can be limited.

Many persistent organic compounds, including PCBs, DDT, and PBDEs, build up in river and ocean sediments. The EPA uses several methods, as described in their Green Remediation program, to clean up heavily polluted areas. Naturally occurring microbes that break down PCBs are used in some cleanup efforts.

There are many examples of successful cleanup projects at large, heavily polluted Superfund sites. A 10-acre landfill in Austin, Texas, contaminated with illegally dumped volatile organic compounds (VOCs), was restored in one year to a wetland and educational park. A U.S. uranium enrichment site contaminated with uranium and PCBs was cleaned using advanced equipment to locate pollutants in the soil. At a polluted wetlands site, soil and water were cleaned of VOCs, PCBs, and lead. Native plants were added to act as natural filters, and a community program was started to monitor pollutant levels in the area. These examples are encouraging because the cleanup was completed quickly and was highly successful.

Studies show that bisphenol A (BPA), certain PCBs, and phthalate compounds are removed from the human body through sweat. Although some pollutants like BPA are removed through sweat, recent scientific methods have been developed to speed up the removal of pollutants from the body. For example, techniques using enzymes like laccase and peroxidase have been proposed to break down BPA into less harmful substances. Another method involves using highly reactive radicals to break down BPA.

Economic effects

Human exposure can lead to certain health problems, including lower intelligence, adult obesity, issues with female reproduction, and issues with male reproduction. These problems may result in reduced work ability, long-term health challenges, or early death in some individuals. One study found that in the European Union, the economic effects of these issues might be about twice as large as those caused by mercury and lead contamination.

Over the past 5 years, the financial cost of health problems linked to endocrine-disrupting chemicals (EDCs) was estimated at about €163 billion in the EU and $340 billion in the United States. This number might be too low because many health effects caused by EDC exposure are difficult to measure fully.