For a condensed toxin list and summary of how to minimize exposure, scroll to the end of the post.
Autism, ADHD, and other neurodevelopment disabilities (NDDs) affect about 10 to 15% of births, with only one-third of those cases attributed to genetic causes.39 This means that environmental factors are likely influencing the remaining 60-70%, as toxins and chemicals interact with genetic susceptibilities in children (see Autism Awareness ). To better understand just how prevalent these chemicals are in our bodies, a 2011 nationally representative study of 268 expecting mothers found certain PFCs, PCBs, phenols, PBDEs, phthalates, PAHs, perchlorates, and organochlorine pesticides in 99-100% of women sampled.40
“Children may be particularly susceptible to the effects of these compounds because they have higher relative exposures compared with adults (because of greater dietary intake per pound), their metabolic (ie, detoxification) systems are still developing, and key organ systems are undergoing substantial changes and maturations that are vulnerable to disruptions.”
Council on Environmental Health
Though it can be difficult to prove a cause-and-effect relationship of a single chemical to autism and ADHD, experts have nailed down the major culprits. Here are the top chemicals suspected of causing autism, ADHD, and Neurodevelopment Disabilities (NDDs) from the experts at The Mount Sinai Children’s Environmental Health Center, with the support of the National Institute of Environmental Health Sciences and Autism Speaks.
Note: This list has been expanded to include action items, simple language, and supporting research. 41, 42
Lead
What is it? Lead is a heavy metal and powerful neurotoxin that has been shown to cause brain damage in developing babies and children.
Where do we find it? Lead can be found in the paint in homes, buildings, and day care centers built before 1978 and in old plumbing. Lead dust is the #1 cause of lead poisoning, and it is not always visible to the human eye. Babies and young children get exposed to lead when they put something with lead dust into their mouths.43 Lead can also get into drinking water when plumbing materials that contain lead corrode, especially where the water has high acidity or low mineral content that corrodes pipes and fixtures.
How do I avoid or minimize it? Do not sand, paint, or renovate an old home while pregnant. Consider lead testing if your home was built before 1978. Do a thorough cleanup after all remodeling projects with wet mops, wet cloths, and a HEPA vacuum (a high-efficiency particulate air filter removes very fine particles from the air that pass through the filter.) Use a dust sampling kit to test for lead dust after the cleanup. Drink filtered water if you are concerned about lead leaching from older pipes (pipes without lead were mandated in 1986.) Avoid shopping at bargain stores for baby toys that will go in baby’s mouth, such as dollar-type stores. Researchers note that bargain stores have the highest amounts of lead and arsenic in their toys and toy jewelry.44
Methylmercury
What is it? This organic compound is created by coal-powered industrial plants and ends up in our rivers, lakes, and oceans.
Where do we find it? Methylmercury is found in fish and shellfish. A fetus is exposed to mercury in the womb, due to a mother’s consumption of fish. The developing fetal nervous system is significantly more sensitive to mercury, especially during early gestation. Impacts on cognitive thinking, memory, attention, language, and fine motor skills have been seen in children exposed to mercury in the womb.45
How do I avoid or minimize it? Avoid seafood with the highest levels of mercury while pregnant. Avoid handling and disposing of mercury-containing products while pregnant, such as thermometers, fluorescent light bulbs, and tilt-switches.
Polychlorinated biphenyls (PCBs)
What is it? PCBs are older industrial chemicals used in hundreds of products produced before 1979, including electrical products, insulation, adhesives, caulking, paints, carbon copy paper, and engine coolant. The EPA classifies PCBs as probably causing cancer, and they are also linked to endocrine disruption, developmental disabilities, and decreased immune functions.
Where do we find it? PCBs do not break down in the environment. Instead, they filter into the soil and water and slowly accumulate in animal fat and fish skins and ultimately in us.46 Most people are exposed to PCBs by eating contaminated fish, meat, and dairy products.
How do I avoid or minimize it? PCBs collect in animal fat and fish skins, so trimming these can reduce exposure. Eat wild salmon. Studies show that PCBs can accumulate in farm-raised salmon, due to smaller feed fish. Steer clear of older fluorescent lights that may still have older transformers or ballasts with PCBs. Keep young children from touching, peeling, and chewing older caulk.47
Organophosphate pesticides
What is it? This acutely toxic group of pesticides has a range of problems associated with prenatal and early childhood exposure, such as impaired memory, mental and emotional problems, and higher risk for ADHD. Organophosphate pesticides (OP) disrupt the nervous system by interfering with an enzyme that regulates nerve impulses and acts as an important chemical regulator of brain activity.
Where do we find it? We find organophosphates, such as chlorpyrifos, on conventional fruits and vegetables (the largest market for chlorpyrifos is corn.) Organophosphates are also used to control cockroaches and pests in city apartments.
How do I avoid or minimize it? Prioritize organic fruits and vegetables. Eat a variety of fruits and vegetables from different stores and sources. Wash fruits and vegetables under running water and peel away skins. In homes with pests, clean up food crumbs and seal cracks and crevices as your first defense.
Organochlorine pesticides
What is it? Organochlorine pesticides, solvents, and spray fumigants, known by names such as DDT and chlordane, have largely been banned in the U.S. and Europe, due to health and safety concerns; yet they are widely used in developing countries, especially for fighting malaria. Because of their chemical makeup, organochlorines break down very slowly and remain in soil, water, and ultimately in the fatty tissues of our bodies. Organochlorine pesticide exposure is associated with several chronic diseases and cancers, including Parkinson’s, neurological disorders, birth defects, and abnormal immune function.48
Where do we find it? Organochlorine pesticide remnants can still be found in agricultural storage facilities and the environment. Banned in 2010, Endosulfan was one of the last organochlorine pesticides on the market used on vegetables, apples, and melons.49
How do I avoid or minimize it? Prioritize organic fruits and vegetables. Eat a variety of fruits and vegetables. Wash fruits and vegetables under running water and peel away skins.
Endocrine disruptors (ECDs), such as phthalates and bisphenol A (BPA)
What is it? ECDs are chemical toxins that act like hormones, tricking the body into over-responding, responding at the wrong time, or blocking natural reactions. Bisphenols are used in the lining of metal cans to prevent corrosion.
Where do we find it? ECDs are found in Bisphenol A/ BPA (food and soda can linings, water bottles, and receipt paper), phthalates (pronounced THAL-ates, which are in plastics, cosmetics, vinyl tile, and air fresheners), and flame retardants (clothing, furniture coverings, computers, and mattresses).50
How do I avoid or minimize it? Limit the use of canned goods and water bottles. Always reheat foods in glass, not plastic containers. Avoid plastics, but if you must use them, avoid the 3, 6, and 7 recycle symbols, and look for symbols 2, 4, and 5. Be wary of hand-me-down plastic toys, bottles, teethers, and feeding products made before 2009. Buy cosmetics and personal care products with safer ingredients. Avoid air fresheners and products with “fragrance” as an ingredient (phthalates are used to help to stabilize chemicals and make fragrance oils last longer.) Check for use of flame retardants on clothing, furniture, and baby products.
Automotive exhaust
What is it? Vehicle emissions contain volatile organic compounds (VOCs), oxides of nitrogen, particulate matter, and carbon monoxide. While scientists are only beginning to understand the link between motor vehicle exhaust and brain cell development, evidence for a link between automotive exhaust and brain disorders is growing.51
Where do we find it? Exhaust levels are highest next to busy highways or in densely populated areas.
How do I avoid or minimize it? Try to avoid living next to a busy highway.
Polycyclic aromatic hydrocarbons (PAHs)
What is it? PAHs are organic compounds that exist naturally in coal, crude oil, and gasoline. They are released into the air as carcinogens by the incomplete burning of fossil fuels.
Where do we find it? PAHs are present in fossil fuel products, and PAH levels may be 10 times greater in urban areas than rural areas. Around the home, PAHs are found in burned meat, anti-dandruff shampoos, cigarette smoke, mothballs, and coal-tar driveway sealants.
How do I avoid or minimize it? Eat less charbroiled meats, avoid cigarette smoke, and use nontoxic alternatives to mothballs, such as cedar chests, vacuuming often, and plant-based deterrents. Remove your shoes before entering your home, especially if you have contact with heavy oils, asphalt, or roofing tar.52
Brominated flame retardants (polybrominated diphenyl ethers or PBDEs)
What is it? These compounds work to inhibit combustible materials, such as a sofa, from igniting (thanks to heavy lobbying by the tobacco industry in the 1970s). PBDEs are transmitted into our lungs through dust and into our blood through ingestion and skin contact. Mothers participating in research studies have been shocked to learn they had PBDEs in their breast milk. PBDEs are linked to cancer, autism, infertility, and other neurological and developmental problems.
Where do we find it? These chemicals are found in mattresses, furniture foam, motor vehicles, TVs and computers, and coatings on fabrics.53 In 2011, a study of 101 widely used baby products found that 80% of them contained flame retardants.54 PBDE levels have doubled in people every three to five years for the past three decades.
How do I avoid or minimize it? Throw away ripped items with foam padding inside and watch for PBDE dust when pulling up old carpet. New foam items are not likely to contain PDBEs; however, foam padding or furniture produced before 2005 should be inspected carefully. Use a vacuum fitted with an HEPA filter to reduce PBDE dust.
Perfluorinated compounds (PFCs)
What is it? PFCs, or non-stick chemicals, are widely used to make products resistant to stains, grease, and water. Teflon and Scotchgard are two recognized brand names of PFCs. PFCs break down very slowly in the environment and bind to organic tissue, including those that make up human blood and the brain. PFCs have been linked to several types of cancer.
Where do we find it? PFCs have wide usage in stain-resistant sprays for carpets and upholstery, fire-retarding foams, nonstick cooking surfaces, and grease-proofing of paper and paperboard used in food packaging. We find PFCs in stain-resistant carpets and furniture, grease-resistant food packaging (fast food containers, pizza boxes, and microwave popcorn), non-stick cookware, dental floss, clothing, and shampoo.
How do I avoid or minimize it? Check personal care labels for the words “fluoro” or “perfluoro” (dental floss, cosmetics, moisturizers, and eye makeup). When you start seeing scratches in your cookware, replace it with cast iron or untreated stainless steel. Choose clothing, carpeting, and furniture without stain-resistant treatments.55
Additional Neurotoxins
Dr. Philip Landrigan at Mount Sinai School of Medicine in New York and his colleague, Dr. Philippe Grandjean at Harvard School of Public Health, have studied industrial chemicals for over 30 years. As autism and ADHD prevalence rates have increased, these scientists have sounded the alarms calling for the urgent formation of an international clearinghouse for industrial chemicals to fight this “silent, global pandemic.” 39
The list of neurotoxins was also updated to include:
Arsenic
What is it? Arsenic occurs naturally in the environment (in rocks, air, soil, and water) and as a by-product of agricultural and industrial activities. Arsenic is perhaps less known for its neurological nastiness than as one of the most prominent environmental causes of cancer mortality in the world. Arsenic has been linked to lung, skin, and bladder cancers, heart disease, stroke, and diabetes. However, it can also interfere with brain development and cause behavioral problems.
Where do we find it? This odorless, tasteless potent poison is found in small amounts in our food and water.
How do I avoid or minimize it? Widespread high concentrations of arsenic are found in the West, Midwest, parts of Texas, and the Northeast. Get your water tested if you drink from a well, especially in New England (Maine to Massachusetts) or the Midwest (Michigan and Minnesota), which are areas with high natural levels of arsenic in rock, or if you live in an area with mining or big agriculture (central valley California, Western states), if you live near metal smelters where metal is made, or if you live near a garbage incinerator. Dr. Landrigan and Consumer Reports also recommend avoiding or limiting rice consumption, especially rice from Texas and Louisiana, noting that the Gulf Coast areas treated cotton crops a century ago with arsenic pesticides.
Toluene
What is it? Toluene is a colorless, flammable liquid.
Where do we find it? Toluene is added to gasoline to improve octane ratings. It is also used to produce benzene and other household products and solvents, such as paint, paint thinner, gasoline, rubber cement, nail polish, and detergents. Solvents have been linked to hyperactivity and aggressive behavior.
How do I avoid or minimize it? If you smell fumes from these products, leave the room. Don’t deliberately sniff it. Avoid exposure in the workplace, such as printing and painting.
Manganese
What is it? Manganese is a naturally occurring substance used in steel production to improve hardness and strength. Excessive manganese levels are linked with diminished intellectual function (ADHD and reduced IQ) and impaired motor skills (Parkinson’s disease).56, 57
Where do we find it? Manganese is a normal constituent of air, water, soil, and food. As a trace element found in people’s diet, manganese in small amounts is essential to keeping your organs healthy, including the brain. However, high concentrations can be harmful. Pregnant women, infants and children are exposed to manganese mostly through diet (cereals, leafy vegetables, fruit, and fruit juices), including breast milk and formula. Vegetarians who consume foods rich in manganese, such as grains, beans, and nuts, and heavy tea drinkers may have higher than normal manganese levels. Manganese inhalation can also be toxic.
How do I avoid or minimize it? Check your well water for manganese levels, especially if you are pregnant. Filter your water. Avoid soy formulas with high manganese levels.58 Do not feed baby soy or rice milk beverages in the place of infant formulas.59 Limit exposure to factories with welding or manganese products, mining activities, and automotive exhaust.
Fluoride
What is it? Fluoride compounds are salts that occur when the element fluorine combines with rocks or soil.
Where do we find it? Fluoride is found in toothpaste and drinking water. Although helpful in small doses for dental health, too much fluoride can lead to tooth and bone lesions and other neuro-developmental defects. An analysis of 27 studies on high levels of fluoride (mostly in China) concluded that high concentrations of fluoride can cause adverse effects on the brain.60 Another study published in the journal JAMA Pediatrics in August 2019 suggests that fluoride consumed by pregnant women can decrease the IQ of their children. 62
How do I avoid or minimize it? Watch fluoride levels in your water. Keep young children from ingesting toothpaste by smearing small amounts on their toothbrush and keeping tubes out of reach.
Tetrachloroethylene
What is it? This is a chemical used for dry-cleaning and metal degreasing.
Where do we find it? When you bring clothes home from the dry cleaners, tetrachloroethylene (perchloroethylene or PERC) is released in small amounts into the air. It can also be found in drinking water.61
How do I avoid or minimize it? Dry-clean your clothes without the use of PERC. If you cannot find a PERC alternative, air out recently dry-cleaned clothes. Avoid living in an apartment directly above a dry-cleaning facility.
A Review of the Toxins.
- Lead
- Methylmercury
- Organophosphate pesticides
- Organochlorine pesticides
- Endocrine disruptors (ECDs), such as Phthalates and Bisphenol A (BPA)
- Polychlorinated biphenyls (PCBs) or pre-1979 industrial chemicals
- Automotive exhaust
- Polycyclic aromatic hydrocarbons (PAH) or fossil fuel products
- Brominated flame retardants (polybrominated diphenyl ethers, or PBDEs)
- Perfluorinated compounds (PFCs) or Teflon and Scotchgard
- Arsenic
- Toluene
- Manganese
- Fluoride
- Tetrachloroethylene or dry-cleaning chemicals
To focus on the worst of the worst neurotoxins, avoid or minimize your exposure to:
Lead, Mercury, Pesticides, and Endocrine-Disrupting Chemicals, such as BPA and phthalates
Let’s review: how to minimize exposure.
- Lead: have your pre-1978 home tested for lead, watch for chipping paint in older homes, don’t remodel while pregnant, filter your water
- Mercury: eat fish and seafood low in mercury
- Pesticides and insecticides: eat organic foods (prioritize The Dirty Dozen fruits and vegetables for buying organic to reduce up to 80% of pesticide exposure), wash fruits and vegetables under running water, scrub with a brush, minimize household weed killers and insect sprays, be mindful if you are living near a golf course, farm, or public space that is frequently sprayed with pesticides.
- BPA: skip canned goods from the grocery store if not labeled BPA-free, use BPA-free plastics, limit drinking bottled water (Note: you can research which brands and which canned or bottled foods are packaged with BPA. For example, here is Trader Joe’s list of BPA-free canned goods and those packaged with BPA. Acidic foods, such as canned tomatoes and mandarin oranges, are likely to have BPA in the lining.)
- Phthalates/Vinyl/PVC-plastics: drink from stainless steel or glass water bottles, use glass to heat and re-heat food, be plastics aware: lose #3, 6, and 7 plastics and choose #2, 4 and 5 plastics. Choose fragrance-free products (avoid the ingredient “fragrance” or synthetic fragrances/phthalates in cleaners, detergents, and personal care products.)
- Brominated fire retardants/ polybrominated diphenyl ethers (PBDEs): throw away ripped items or replace decaying or crumbling furniture with foam padding inside (especially pre-2005), watch for PBDE dust when pulling up old carpet (PBDEs are found in the foam padding beneath carpets), don’t buy baby gear, mattresses, and household products coated in fire retardants
- Polychlorinated biphenyls (PCBs): avoid eating fish skins and animal fat, eat wild salmon (not farmed); Catfish, buffalo, and carp usually have the highest PCB levels among freshwater bottom-feeding fish
- Arsenic: get your water tested if you drink from a well, if you live near metal smelters where metal is made, or if you live near a garbage incinerator
- Toluene: avoid inhaling or sniffing paint, paint thinners, gasoline, rubber cement, nail polish, and other solvents; if you smell fumes, leave the room
- Manganese: check your well water for manganese levels, filter your water, do not feed baby soy or rice milk beverages in place of infant formula
- Perfluorinated compounds (Teflon): keep heat at medium or below for non-stick cookware; opt for iron or stainless steel pots and pans, if possible
- Toxic household cleaners: mix your own cleaning ingredients or use green cleaning products
- Other chemicals brought into the home: use a door mat, take shoes off with a shoe organizer by the door, use a high-efficiency particulate air (HEPA) filter vacuum cleaner, dust with a wet cloth, use sticky pads and crumb cleanup for critters and not indoor sprays
For those concerned about chemical exposure, minimize potentially problematic foods
- High-mercury fish, such as swordfish, king mackerel, shark, tilefish, marlin, orange roughy, and tuna (bigeye, ahi)
- The first four fish are labeled as AVOID by FDA and EPA for pregnant women and children.
- Farmed seafood and salmon (may contain PCBs)
- Food from cans and plastics made with BPA
- Processed meats with nitrates/nitrites and other chemicals
- Meat from animals treated with hormones (beef, lamb)
- Non-organic fruits and vegetables
- Non-organic dairy products
- Food additives: artificial sweeteners (e.g., aspartame), stabilizers and preservatives (e.g., sodium benzoate)
- Food dyes: artificial food colors have been linked to hyperactivity in children. In 2010, the European Union required warning labels on foods with artificial dyes stating that they “may have an adverse effect on activity and attention in children.”
Notes
- Fish: Advice About Eating Fish (for pregnant women, breastfeeding mothers, and young children). – FDA website
- Farmed seafood and salmon: Mayo Clinic article on fish/salmon and PCBs.
- BPA and pregnancy: journal article
- Steroid Hormone Implants Used for Growth in Food-Producing Animals: FDA website – “Since the 1950s, the Food and Drug Administration (FDA) has approved a number of steroid hormone drugs for use in beef cattle and sheep, including natural estrogen, progesterone, testosterone, and their synthetic versions. These drugs increase the animals’ growth rate and the efficiency by which they convert the feed they eat into meat.”
- Organic Foods: For more information on which organic foods to prioritize on a budget, read our post on Organic Foods.
Graphics permission by Jackie Lay (The Atlantic)
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