PFAS are often called “forever chemicals.” These synthetic compounds have been used in industrial processes and consumer products for decades, and they have become one of the most widely detected contaminants in drinking water around the world.

Unlike many other chemicals, PFAS do not easily break down in the environment or in the human body. Because of this persistence, scientists have become increasingly concerned about PFAS in water and their potential health effects. 

In recent years, peer reviewed research has linked PFAS exposure to several biological changes in humans, including disruptions to hormone systems, altered cholesterol levels, and potential impacts on fertility and thyroid function.

What Are PFAS and where do they come from?

PFAS stands for per and polyfluoroalkyl substances, a large group of synthetic chemicals that have been manufactured since the 1940s.

These chemicals were designed to resist heat, water, and oil. Because of those properties, PFAS have been used in products such as:

• Nonstick cookware
• Waterproof clothing
• Food packaging
• Firefighting foams
• Stain resistant textiles

Their extremely strong carbon fluorine bonds make PFAS highly stable. This stability means they persist in soil, air, and drinking water sources, sometimes for decades.

As a result, human exposure has become widespread. Studies have detected PFAS in blood samples from populations across the world, demonstrating that these chemicals are now present in many people.

PFAS in Water and Human Exposure

One of the most common exposure pathways is drinking water.

PFAS contamination can enter water systems through several routes, including:

• Industrial manufacturing discharge
• Firefighting foam runoff from airports and military bases
• Landfill leachate
• Wastewater treatment plant discharge

Because PFAS do not degrade easily, they can travel long distances through groundwater and accumulate in municipal water supplies.

This is why the issue of PFAS in water has become a growing public health concern.

Once PFAS enter the human body, they can remain in blood and tissues for years. Research shows that certain PFAS compounds have human half lives measured in multiple years, meaning repeated exposure can gradually increase total body burden.

PFAS and Thyroid Dysfunction

PFAS are classified as endocrine disrupting chemicals, meaning they can interfere with hormone signaling pathways.

Several scientific reviews have examined how PFAS interact with the thyroid hormone system and show that the thyroid gland regulates metabolism, growth, and energy balance through hormones such as thyroxine (T4) and triiodothyronine (T3). 

Laboratory studies and epidemiological research suggest that PFAS can interfere with thyroid hormone homeostasis and thyroid receptor signaling. Researchers have reported associations between PFAS exposure and altered thyroid hormone levels in human populations.

Disruptions to thyroid hormone regulation can have wide ranging effects because the thyroid system influences metabolic activity throughout the body.

PFAS and Fertility

A growing body of research has also examined the relationship between PFAS exposure and reproductive health.

Some studies have found evidence of a correlation between PFAS exposure and reduced fertility, including longer time to pregnancy in women with higher PFAS concentrations in blood.

PFAS can interact with hormone pathways involved in reproductive function, which may influence ovarian activity, menstrual cycles, and other aspects of fertility.

Researchers emphasize that additional studies are still needed to fully understand the mechanisms involved, but current evidence suggests that PFAS exposure may negatively affect reproductive health in certain populations.

PFAS and Hormone Imbalance

Hormone systems rely on carefully balanced signaling between glands, tissues, and circulating hormones.

Because PFAS can act as endocrine disrupting chemicals, they may interfere with several hormonal pathways. Researchers have observed that PFAS compounds can interact with receptors involved in metabolic regulation and endocrine signaling.

These interactions may contribute to hormone imbalance, which can influence metabolism, immune function, and reproductive biology.

Scientists continue to study how long term exposure to PFAS may affect endocrine systems over time.

PFAS and Elevated Cholesterol

One of the most consistently observed associations in PFAS research involves cholesterol levels.

Multiple epidemiological studies have reported that individuals with higher PFAS concentrations in their blood often have higher total cholesterol levels.

Researchers have investigated potential mechanisms for this association. Some studies suggest PFAS may alter liver metabolism or affect pathways involved in lipid regulation.

While research is ongoing, the repeated observation of this relationship across different populations has made elevated cholesterol one of the most widely reported PFAS health effects.

PFAS, Microplastics, and Plastic Exposure

Scientists are increasingly studying how plastic exposure may interact with PFAS exposure.

Microplastics are small plastic particles that form when larger plastic materials degrade. These particles are now found in air, soil, food, and drinking water.

Some research suggests that microplastics can act as carriers for environmental pollutants, including PFAS. Because plastics and PFAS often originate from similar industrial sources, individuals who are frequently exposed to plastics may also experience higher exposure to these persistent chemicals.

Researchers continue to investigate how combined exposure to plastics and chemical contaminants may influence overall human health.

Does a Water Filter Remove PFAS?

Because drinking water is a common exposure pathway, many people ask an important question:

Does a water filter remove PFAS?

Scientific studies have shown that certain filtration technologies can significantly reduce PFAS concentrations in drinking water. Among the most widely studied technologies are activated carbon filters and reverse osmosis systems.

Activated carbon materials can adsorb many organic contaminants due to their high surface area and porous structure. When water passes through a dense carbon block filter, PFAS molecules can bind to the carbon surface and be removed from the water stream.

For households concerned about PFAS in water, selecting the best water filter for PFAS can be an effective step toward reducing exposure.

Reducing Exposure to Forever Chemicals

While it is difficult to completely eliminate exposure to PFAS, several practical steps may help reduce overall intake:

• Using a water filter tested for PFAS reduction
• Limitting food packaging that contains grease resistant coatings
• Avoiding heating food in plastic containers
• Reducing use of stain resistant or waterproof chemical coatings when possible

Small changes in daily habits can help lower cumulative exposure over time.

As research continues to evolve, scientists are working to better understand how forever chemicals in water influence human health and how exposure can be reduced.

Sources

1. Thyroid Disrupting Effects of Old and New Generation PFAS
   

2. Per-polyfluoroalkyl substances (PFAS) as thyroid disruptors: is there evidence for multi-transgenerational effects?

3. Perfluoroalkyl substances and time to pregnancy in couples from Greenland, Poland and Ukraine

4. Exposure to polyfluoroalkyl chemicals and cholesterol, body weight, and insulin resistance in the general U.S. population

5. Per- and polyfluoroalkyl substances (PFAS) exposure and thyroid cancer: systematic review and meta-analysis