There are more than 80,000 industrial chemicals in widespread use across the US. Around 3,000 of these chemicals are in products that we come into contact with every day, including clothing, carpets, toys, cleaning products and cosmetics. But is it safe to be so frequently exposed to these chemicals?
Past studies have associated chemical exposure with negative impacts on health. In 2012, Medical News Today reported on a study suggesting that routine exposure to toxic chemicals may increase the risk of breast cancer, although this link has never been confirmed.
However, there is one health issue as a result of chemical exposure that is now widely accepted in the medical world - its effect on child brain development.
In 1993, a report from the National Research Council titled Pesticides in the Diets of Infants and Children first suggested that children, specifically the developing fetus, are significantly more sensitive to the toxic effects of chemicals than adults.
Numerous studies have supported this discovery. Last year, Medical News Today reported on a study from the Royal College of Obstetricians and Gynaecologists in the UK, suggesting that pregnant women need to be aware of unintentional chemical exposure, as it may impact the health of their unborn baby.
But how exactly can chemical exposure affect a child's development?
Toxic substances interfere with the brain's natural functions
Harmful chemicals can be absorbed into our bodies through our skin, or we can ingest them through air, food and drinks.
The US Agency for Toxic Substances and Disease Registry (ATSDR) states that pregnant women, children and elderly individuals are more sensitive to chemical exposure.
There are approximately 3,000 chemicals in products that we come into contact with every day, such as cleaning products, toys, clothing and carpets.
According to a 2006 study from the Center on the Developing Child at Harvard University in Cambridge, MA, some toxic chemicals can interfere with the natural function of genes, proteins and other small molecules in the brain.
The paper states that the immature brain is much more vulnerable to toxic exposure than the brain of an adult.
The mature brain has a barrier of cells that stops chemicals in the blood stream from entering brain tissue. But the developing fetus does not have this protective barrier, meaning it is more vulnerable to toxic substances.
There are a series of chemicals that have been associated with neurodevelopmental disorders. These include lead, mercury, fluoride, dichlorodiphenyltrichloroethane (DDT), manganese, chlorpyrifos (a pesticide) and tetrachloroethylene (a solvent).
Lead can interfere with important neurotransmitters in the brain, including dopamine, glutamate and acetycholine, while mercury can disrupt brain development by blocking enzymes that regulate brain function. It also stops cells from dividing, meaning there are fewer neurons and support cells produced in the brain.
Hidden toxicity of chemicals worrying
US organizations, including the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA), have imposed regulations on chemicals that have been linked to neurodevelopmental disorders in order to protect children's health.
But a recent study from the Harvard School of Public Health in Boston, MA, states that there are 214 chemicals that have been linked to human brain damage that have not been regulated.
Furthermore, the researchers note that of the 80,000 chemicals widely used in the US, the vast majority of these have not been tested for their toxic effects.
"Sadly, in the US, the legal requirements for testing chemicals before they come on to the market are almost non-existent," said study author Dr. Phillip Landrigan, of the Department of Preventive Medicine at the Icahn School of Medicine at Mount Sinai in New York, NY.
He told Medical News Today:
"These chemicals are put into products, they are not tested, they get out into the environment and get into people.
Some, I am quite sure, will turn out to be benign. But I am sure there are some that are hidden. There are some that are probably causing harm that we have not yet recognized as dangerous."
Recent studies have focused on the potential harm that certain unregulated chemicals can cause.
We recently reported on research suggesting that synthetic chemicals used in food packaging - known as food contact materials (FCMs) - may leak into the food we eat and harm our long-term health.
Other research has found that pregnant women exposed to phthalates - chemicals found in some deodorants, lotions and perfumes - may be at increased risk of preterm birth.
But according to the study researchers, "our very great concern is that children worldwide are being exposed to unrecognized toxic chemicals." They say this exposure could lead to a "global neurodevelopmental epidemic."
So what can be done to prevent this possible epidemic?
Change in US chemical policy needed
In a 2011 study, Dr. Landrigan and colleagues say "the finding that children are uniquely vulnerable to synthetic chemicals indicates the need for fundamental revision of US chemical policy."
Talking to Medical News Today, Dr. Landrigan said that US policymakers would benefit from adopting a chemical testing policy similar to that enacted by the European Union (EU) in 2007.
The Honor Whiteman (resource no longer available at ec.europa.eu)