The study looked at “contemporary and emerging chemicals”, many of which scientists know very little about when it comes to potential health concerns.
Some of these substances were more common in certain subsets of the population. For example, Hispanic participants were significantly more likely to have certain kinds of phthalates, parabens and bisphenols than non-Hispanic white participants — and participants with a bachelor’s degree were more likely to have a certain type of benzophenone and fungicide than participants with less education.
People are exposed to all sorts of chemicals through consumer products, food, the air and drinking water that can lead to health issues, Tracey Woodruff, a public health researcher at the University of California, San Francisco and one of the study’s authors, told The Independent.
“But that’s only for a very small fraction of the chemicals to which we’re exposed,” she says, adding that studies like this one, published on Tuesday in Environmental Science and Technology, can help scientists start to quantify our exposure to and risk from these chemicals.
The research team took samples from 171 pregnant people in the US, with a mix of people from different ages, racial backgrounds and education levels. They looked the chemicals in question in all the study participants, noting whether or not each person had enough of that chemical to be detectable.
Out of 89 different materials they looked for, they found 73 in at least one person — and 36 of them in more than 50 per cent of people they studied.
Commonly occurring substances included some types of benzophenones, which can block UV rays and show up in some sunscreens and cosmetics, and parabens, which are often used as preservatives.
Other common substances included some types of phthalates, which are chemicals used in making some plastics, as well as some flame retardants, insecticides and fungicides.
Bisphenol-A, a plastics ingredient commonly known as BPA, was found in 61 per cent of participants, and a similar substance called BPS was found in 84 per cent.
The research team found plenty of associations between different chemicals and things like racial background, education and age. But what might explain these associations — use of different personal products for example — is a subject for future research, Dr Woodruff says.
In addition, future research is needed to understand more about the toxicity of these chemicals and how they might impact human health.
Public health researchers do have some clues about the health effects of some of the chemicals — such as concerns over how BPA influences hormones, which lead to the spread of “BPA free” plastics. But studies that prove that health issues are definitively caused by certain chemicals are notoriously hard to do.
Many of the substances they chose to look at are things that scientists are concerned about, however — because of their similarity to other products with known issues, tests done on animals or other studies, Dr Woodruff says.
This study’s data will become part of a much larger dataset on chemical exposure through the Environmental influences of Child Health Outcome (ECHO) program — a program supported by the US National Institutes of Health looking at paediatric health.
“The ECHO cohort database is set up so that many people can go and look at these questions and get answers to very important questions that could be influencing exposures and people’s health,” Dr Woodruff says.