Scientists are able to monitor the health effects of only a few hundred of the roughly 40,000 commercially used chemicals listed in the US Toxic Substances Control Act Inventory. The monitored substances are ones that scientists know how to measure well and can find in the human body.
Now, a study uses a new screening technology to identify potentially toxic chemicals that were previously hard to find in human specimens. The study detected 109 industrial chemicals in the blood of pregnant women and newborns, including 55 chemicals never-before reported in people (Environ. Sci. Technol. 2021, DOI: 10.1021/acs.est.0c05984).
The study authors focused on pregnant women and newborns because prenatal exposure to industrial chemicals can lead to health problems such as reduced IQ and childhood cancers, says Tracey J. Woodruff, director of the Program on Reproductive Health and the Environment (PRHE) at the University of California San Francisco. She and her team collected blood samples from 30 pregnant women and their babies’ umbilical cords during delivery. The scientists analyzed the samples using high-resolution mass spectrometry and detected roughly 35,000 chemical features—patterns of chromatographic peaks and retention times—that could correspond to molecules of interest for biomonitoring.
“We wanted to prioritize the chemicals that people are most likely to be exposed to,” Woodruff says, so the researchers developed a screening process that winnows down the list of chemical features to a number of suspected toxic chemicals. The process relies on a suite of software tools that allow researchers to compare the mass spectra of the chemicals found in blood to databases of high-production-volume chemicals and libraries of chemical formulas.
The scientists focused on the suspect chemicals that were detected in all the samples and had not been routinely monitored in people. They tentatively identified 109 chemicals found in pharmaceuticals, pesticides, flame retardants, stain repellents, plasticizers, cosmetics, and other consumer products. The team observed that women with higher socioeconomic status had relatively higher exposures to some of the compounds. “That association could be explained by the fact that with higher buying power, you can bring more products containing flame retardants, plasticizers, or stain repellents into your home,” says study coauthor Dimitri Panagopoulos Abrahamsson, a chemist at PRHE.
In addition to the 55 chemicals never reported before in people, the researchers detected 42 “mystery chemicals” for which the team derived molecular structures but could find no information on what they were used for or what products they were from, Woodruff says. “This points to gaps in [US Environmental Protection Agency] requirements for industry to identify and report the use of chemicals in consumer products, which limits our ability to understand exposures and health effects,” she says.
“We’re very excited about how novel this work is,” says John F. Wambaugh, a research physical scientist at EPA. The screening technology has been applied to other media, such as drinking water, but screening blood is much more challenging because of all of the complex protein molecules in it, he says. Wambaugh adds that he would like to see researchers focus on applying the method more widely—for instance, by using different analytical technology, such as gas chromatography, to detect more compounds.