People aren’t exposed to chemicals one at a time from a single place or product. They’re exposed to combinations, or mixtures, of chemicals from several sources.
A person’s exposure to multiple chemicals from various sources can change how the chemicals interact and how they affect the body, sometimes creating much more harm than exposure to just one chemical would. Pesticides, solvents and the “forever chemicals” known as PFAS are just three of the environmental groups of chemicals associated with health risks.
People are exposed to hundreds of environmental chemicals daily – through the air we breathe, the food and water we consume, and the products we use in our home and on our bodies. These chemicals can also end up in our air or water through industrial pollution or agricultural run-off.
For example, PFAS are commonly detected in drinking water. Because of their stain- and water-resistant properties, they are also intentionally added to cosmetics, clothing, food wrappers, menstrual and incontinence products and even dental floss.
And drinking water may contain heavy metals, solvents, pesticides, PFAS – and possibly many more chemicals, posing health harms on their own and as mixtures.
Many chemicals, many dangers
Peer-reviewed research reports that even metals essential for healthy growth and development can be associated with toxicity when people are exposed to a combination of essential and toxic metals. In one study, manganese, an essential metal, contributed to worse scores on neurodevelopmental tests in children who were also exposed to lead, a highly toxic metal. The more severe outcome may be due to how the chemicals interact once in the body.
The same is true of asbestos, a heat-resistant fibrous mineral used for insulation and fireproofing. Exposure is the main cause of a rare and serious type of cancer called mesothelioma. The risk of this cancer goes up if a person also smokes because the combination of smoking and asbestos is worse for you then either alone.
Harm from chemical mixtures
Chemical mixtures have been associated with a suite of health problems, including: increased risk of developing cancers, harm to a child’s neurodevelopment, impacts to the thyroid, and risks of poor reproductive and cardiometabolic health outcomes.
And you can be at risk from such simple tasks as cleaning your bathroom. If you mix bleach and ammonia, which are both commonly used for cleaning, the result is highly poisonous chlorine gas. Exposure to it can be deadly.
The combination of pollution or personal care products in our body can have the same result. And chemicals that might be considered harmless alone can be toxic when mixed with another.
Studies have shown that exposure to mixtures of pesticides increases the risk of health outcomes such as reproductive and cardiometabolic harm.
The opposite can also be true. What about two chemicals that create health harms individually but do not interact with each other once in the body? In those instances, the total potential risk from exposure to those chemicals at the same time is equal to their individual dangers combined.
Health concerns from mixtures is one of the concepts behind EWG’s Skin Deep® searchable database of personal care products and EWG Verified®, the mark given to cosmetics and other products that meet EWG’s strict standards for efficacy, ingredient safety and transparency.
How are chemicals regulated now?
Risk assessments for people and the environment don’t adequately capture the effects of chemical mixtures. And regulations aren’t always written to address the risks of these mixtures.
Instead, chemicals are usually regulated as single chemicals or sometimes as classes of related chemicals, and many remain underregulated.
In 1976, the landmark U.S. chemical law, the Toxics Substances Control Act, or TSCA, was enacted. At that time, over 60,000 chemicals already in use didn’t need Environmental Protection Agency approval to keep being used. Early efforts to regulate some of those chemicals were stymied by the courts and as a result, the EPA took very little action on chemicals already in use until the law was reformed.
Under a 2016 update to TSCA, the EPA must now review and regulate some of these chemicals, but the process is slow and does not address chemical mixtures directly.
Reducing your chemical exposure
It’s impossible to avoid chemicals in your daily life entirely, but you can lower your exposure to mixtures. Some tips:
- Browse EWG’s Skin Deep database, which scores products based on all their ingredients and their corresponding hazards, which is essentially a mixtures approach. Search Skin Deep for safer products with low hazard scores or that have the EWG Verified mark.
- Use EWG’s Guide to Healthy Living for tips on making healthy purchases. Regular cleaning can help reduce chemical exposures in the home. See EWG’s Guide to Removing Household Dust.
- Reduce exposure to mixtures of pesticides in your produce with EWG’s Shopper’s Guide to Pesticides in Produce™.
- Stay informed about the tools you may want to use to lower exposure to chemicals in your environment. You can find out what mixtures of chemicals may be in your drinking water by using EWG’s Tap Water Database and also check out the EWG water filter guide.
- Review EWG’s page on toxic chemicals for more information on various chemicals, and use EWG’s consumer guides to help reduce exposures to chemicals.
- Take action and support legislation that bans harmful chemicals.
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