Environmental chemicals in food: should you be worried?

Several recent stories in the news media have reintroduced questions related to two chemicals which may be in our food, especially perchlorate and BPA. Perchlorate is a chemical used in fireworks, road flares, explosives, and rocket fuel. It is also sometimes present in bleach and in some fertilizers.Perchlorate  forms naturally in the environment in small amounts. Perchlorate can enter surface and ground waters. It lasts a long time in the environment and is easily absorbed by plants.

Human health effects from perchlorate at low environmental exposures are unknown. In laboratory studies, perchlorate can disrupt the normal function of the thyroid gland. In adults, the thyroid plays an important role in metabolism, making and storing hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. In fetuses and infants, thyroid hormones are critical for normal growth and development of the central nervous system. Perchlorate has been shown to interfere with the human body’s ability to absorb iodine into the thyroid gland which is a critical element in the production of thyroid hormones.

A 2005 Journal of Environmental Science and Technology study analyzed contaminants in agricultural products and found quantifiable levels of perchlorate in 16% of conventionally produced lettuces and other leafy greens, and in 32% of otherwise similar but organically produced samples. Today, traces of perchlorate are found in the bloodstreams of just about every human. Evidence has shown the people are normally exposed to perchlorate through food and water.

The Environmental Protection Agency (EPA) has been tasked with periodically re-evaluating levels of perchlorate allowed in drinking water. In order to limit human exposure through food, as of May 4, 2017, perchlorate may only be used as a component of certain food packaging materials and in food equipment that comes in contact with dry food (only).  Since chemicals are most likely to leach into acidic, fatty, or moist foods; leaching of chemicals into dry foods is far less likely to occur. These recent developments are, therefore, good news for limiting human exposure to perchlorate through food.

Bisphenol A, or BPA, is used to manufacture polycarbonate plastics. This type of plastic is used to make some types of beverage containers, compact disks, plastic dinnerware, impact-resistant safety equipment, automobile parts, and toys. BPA epoxy resins are used in the protective linings of food cans, in dental sealants, and in other products.

General exposure to BPA at low levels comes from eating food or drinking water stored in containers, often plastic, that have BPA. Small children may be exposed by hand-to-mouth and direct oral (mouth) contact with plastic materials containing BPA. Human health effects from BPA at low environmental exposures are unknown. BPA has been shown to affect the reproductive systems of laboratory animals.

The Centers for Disease Control scientists found BPA in the urine of nearly all of the people tested, which indicates widespread exposure to BPA in the U.S. population. If you are concerned about BPA exposure, look for BPA-free items such as water bottles and baby toys. Luckily, it’s become alot easier to find BPA-free items in stores.

Since a recurring concern is the use of plastics, of all kinds, for microwave heating, check out the USDA’s Microwave Ovens and Food Safety for tips on microwave-safe cooking.


Stay food safe! Barb