New tool for estimating people's total exposure to potentially harmful chemicals

Every day, we deal with exposure to numerous chemicals in our daily life. From them, synthetic chemicals adversely affect our health. To estimate our "burden", or cumulative exposure to thousands of synthetic chemicals a team of researchers has developed a new tool.

Keywords: chemicals, PFAS, exposure, burden score, response theory, environmental epidemiology, serum concentrations

PFAS(per- and polyfluoroalkyl substances) is a class consisting of more than 5000 chemicals. Fluorine-carbon bond gives these substances the ability to repel oil and water. Due to this, these substances have made rapid growth in industrial applications and consumer products in recent decades. Examples of PFAS are: 

• Stain and water repellents
• Teflon nonstick pans
• Paints
• Cleaners
• Food packaging

These substances have numerous adverse effects. They do not decompose in the environment. Instead, they accumulate in our surroundings and affect our health. They are associated with various health problems such as high cholesterol, liver damage, thyroid disease, and hormone disorders. In 2007, Centers for Disease Control and Prevention study found that PFAS could be detected in the blood of 98% of the U.S. population.

In a paper published in Environmental Health Perspectives, the team of researchers reported a new tool that will prove to be beneficial for epidemiologists who measure exposure levels of PFAS class of chemicals. 

Lead author Shelley Liu, PhD, Assistant Professor in the Center for Biostatistics, Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai said, "There are few existing methods to quantify total exposure burden of individuals to mixtures of PFAS chemicals that are found in our everyday lives. For the first time we've developed a PFAS burden calculator that takes into account patterns of exposure to many chemicals within the PFAS family, and not just individual chemical concentrations which current methods are focused on. As a result, this robust tool could be extremely useful for biomonitoring by regulatory agencies, and for disease and health risk assessment".

Researchers used national biomonitoring data from the National Health and Nutrition Examination Survey for developing the exposure burden score. They developed this using response theory. Response theory was developed in the educational testing literature to score standardized tests. This is the first time that it was used in environmental epidemiology. 

Specifically, for this research, the researchers used serum concentrations from eight common PFAS  chemicals taken from adults and children. They estimated the PFAS exposure burden by combining a participant's relative exposure to other PFAS biomarkers within the entire chemical class. This methodology can now be used by other epidemiologists by simply plugging their data sets into the online PFAS burden calculator.

The features of this calculator are:

1. It provides a straightforward way to include exposure biomarkers with low detection frequencies.
2. To reduce exposure measurement errors by considering both a participant's concentrations and their exposure patterns.
3. To estimate exposure burden to chemical mixtures

Dr. Liu said, " These could include, for example, looking across populations to determine if there are differences in exposure burden across racial/ethnic or socioeconomic strata, or if exposure burdens are the same between people in the United States or Canada. Or looking across physiological systems and health outcomes -- such as cardiometabolic, hormonal, and immune -- to see which are most perturbed by exposure to PFAS chemicals. This range of applications takes us well beyond anything currently available to the field of population health".

Thus, this research provides an efficient and easy way for calculating exposure to PFAS chemicals.