The average menstruating person will spend about five years of their total reproductive lifespan using an estimated 11,000 tampons, sanitary pads, panty liners and other menstrual products, experts say.

What if some of those menstrual aids contain heavy metals or potentially toxic chemicals linked to chronic diseases and reproductive and developmental problems?

 has found tampons and other menstrual products may contain chemicals such as perfluoroalkyl and polyfluoroalkyl substances, or PFAS; plasticizers, also known as phthalates; and volatile organic compounds, or VOCs, emitted as gas or  from many consumer products.

All these chemical groups have been shown to disrupt the body鈥檚 , which regulates sexual development, metabolism, blood sugar, mood, sleep and more.

Recently,  found arsenic and lead in organic and nonorganic tampons 鈥� and while the levels were small, there is no safe level of exposure to lead, according to the .

However, that study was unable to determine whether heavy metals might leach from tampons into the body, thus making any potential health impact unknown, said senior study author Kathrin Schilling, assistant professor of environmental health sciences at Columbia University鈥檚 Mailman School of Public Health in New York City.

鈥淚 do not want people to panic, but to be aware that heavy metals have been found in these menstrual products,鈥� Schilling said. 鈥淥bviously, the next step is to do research that would show if the metals leach from the tampon into the body.鈥�

The study was also unable to determine whether any metal, even if released into the body, can be absorbed into the vaginal lining and subsequently into the bloodstream, said Amanda Hils, a spokesperson for the U.S. Food and Drug Administration, which  as medical devices.

鈥淲e plan to evaluate the study closely, and take any action warranted to safeguard the health of consumers who use these products,鈥� Hils said in an email.

Vaginal tissue is more permeable than other parts of the body, so if studies were to find that heavy metals 鈥� or worrisome chemicals 鈥� do leach from menstrual products into the body, it could be a significant problem, said Anna Pollack, associate professor of global and community health at George Mason University in Fairfax, Virginia. She was not involved in the pilot study.

鈥淚 am most concerned with menstrual products that are used inside the body,鈥� said Pollack, who co-authored  on contaminants in tampons, sanitary pads, menstrual cups and other products.

鈥淗owever, there is no reason for people to be afraid to use menstrual products at this time,鈥� she added. 鈥淚 would just be aware of the issue and monitor any research that develops.鈥�

Heavy metals in tampons

Schilling and her team tested 30 tampons from 14 brands purchased from major online retailers and stores in the United States, United Kingdom and Greece. The researchers conducted a blinded study, so they did not know the brands.

The team ran tests for 16 heavy metals: arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, manganese, mercury, nickel, lead, selenium, strontium, vanadium and zinc.

鈥淲e found an average of 100 nanograms per gram of lead, and 2 nanograms per gram of arsenic in the tampons,鈥� Schilling said, 鈥渂ut there was no detectable level of chromium and no detectable level of mercury, which is very good.鈥�

Organic tampons contained higher levels of arsenic, while nonorganic tampons had higher levels of lead, the study found.

鈥淭he average lead concentration in tampons was about 10 times higher than the maximum levels currently allowed in drinking water,鈥� Schilling said, adding that arsenic levels were five times lower than current limits for drinking water.

鈥淚t鈥檚 important to note that arsenic shouldn鈥檛 be present in tampons at all, and we don鈥檛 yet understand the effects of vaginal exposure since it hasn鈥檛 been studied,鈥� she said. 鈥淭here is no safe level of lead exposure, and it has been shown to cause reproductive health issues in women.鈥�

How did detectable levels of these heavy metals get into tampons in the first place?

First, most tampons are made of cotton or a mixture of cotton and rayon, a semi-synthetic fibre made from wood pulp. Arsenic is a natural element found in soil, water and air, while lead and other heavy metals are a natural part of Earth鈥檚 crust 鈥� so plants can easily absorb metals as they develop.

Additional chemicals found in menstrual products

The soil and water of the United States and other parts of the world are also heavily contaminated with both metals and chemicals used to produce plastic products, experts say.

Heavy metals can be  of manufacturing plants, mining facilities and smelting processes, while PFAS and other chemicals  from human waste, consumer products discarded in landfills and byproducts from fluorochemical manufacturing plants.

is contaminated with some of the 12,000 types of PFAS, according to an  by the U.S. Geological Survey.

Chemicals called phthalates have been discovered in sanitary pads, panty liners and tampons, according to Pollack鈥檚 review. Phthalates are in consumer products such as shampoo, makeup, perfume and children鈥檚 toys and have been linked to , such as  and  in baby boys and  and  in adult males. Both phthalates and PFAS have also been linked to the rise in .

 advocacy groups Mamavation and Environmental Health News, in collaboration with the  at Carnegie Mellon University in Pittsburgh, looked at levels of PFAS in menstrual products. The investigation found  of sanitary pads, incontinence pads and tested panty liners contained PFAS, as did  of tampons and  of period underwear.

Manufacturers use PFAS, often called 鈥渂ecause they do not easily break down in the environment, in  to prevent grease and water from soaking through food wrappers and beverage cups. The chemicals are also used to make carpeting, clothing and furniture resistant to stains, water and grease damage.

A  found PFAS may alter hormonal and metabolic pathways needed for growth and development in young children, teens and young adults. PFAS chemicals have also been linked to an increased risk of adult kidney cancer and abnormally high cholesterol levels and decreased antibody response to vaccines in both adults and children.

However, the mere presence of a chemical is not an indication of risk or adverse effect, according to the American Chemistry Council, an industry association.

鈥淎s the Centers for Disease Control and Prevention , 鈥楾he measurement of an environmental chemical in a person鈥檚 blood or urine is a measure of exposure; it does not by itself mean that the chemical causes disease or an adverse effect,鈥欌�� a spokesperson for the council told CNN.

How to protect yourself

Tampon makers and the FDA recommend that tampons not be used at night or for longer than eight hours due to a greater risk of  a deadly bacterial infection that can cause organ failure and death if not treated.

That advice also applies to anyone concerned about heavy metals or chemicals in their menstrual products, said Nancy King Reame, professor emerita of health promotion and risk reduction at the School of Nursing at Columbia University Medical Center.

鈥淏ut because the vaginal microbiome, including menstrual fluid, is the least understood organ system in the body, real-world advice on the use of period products based on these findings is premature to say the least,鈥� said Reame, who assisted on the tampon study.

Other recommendations include washing your hands before and after inserting or removing a tampon to reduce bacterial spread, changing tampons every four to eight hours and using the lowest absorbency possible.

鈥淚f you can wear one tampon up to eight hours without changing it, the absorbency may be too high,鈥� .

Signs of toxic shock, which include a sudden high fever, diarrhea, dizziness, vomiting or a rash that looks like a sunburn, need immediate medical attention.

In addition, 鈥渋f you have discomfort, pain or other unexpected symptoms like unusual discharge when trying to insert or wear a tampon, or if you have an allergic reaction, stop using tampons and contact your provider,鈥� the FDA said.