MADRID 18 Oct. (EUROPA PRESS) –
Studies of chemicals in blood often capture only a small, unknown fraction of the entire chemical universe. Now, a new approach aims to change that. This is a work by researchers from the Beate I. Escher Helmholtz Environmental Research Center – UFZ at Eberhard University (Germany) who used blood samples from pregnant women collected between 2006 and 2008.
The researchers report in an article published in Science that they have quantified many complex mixtures of chemicals that may pose neurotoxic risks, even when the individual chemicals were present at apparently harmless levels.
“The quantitation of 294 to 473 chemicals in plasma is a significant improvement compared to the usual selective analysis focusing on only a few selective analytes,” the authors write. They note that screening studies are typically limited to fewer than 100 identified chemicals. Their work represents a novel approach for biomonitoring of the “toxic exposome.” The human exposome encompasses all the environmental factors that a person experiences throughout their life, such as what they eat, where they live, and the chemicals they interact with. Among these myriad factors, humans are exposed to hundreds, if not thousands, of chemicals daily.
The toxic exposome has become of particular concern, as increasing production of chemicals has been linked to an increase in diseases and developmental disorders, especially in children exposed to neurotoxic and endocrine-disrupting substances. Although human biomonitoring (HBM) studies aim to measure chemical load in biological samples such as blood and urine, they often focus on a limited set of known chemicals and overlook the complexity and variability of the toxic exposome in its entirety. Furthermore, few studies have considered the toxicity of chemical mixtures in the body.
To address these limitations, the researchers adapted a bioassay originally developed for water quality assessment to characterize the chemical load and effects of the mixture of chemicals present in blood. Combining high-resolution chemical analysis with a high-throughput in vitro assay for neurotoxicity, blood plasma samples from 624 pregnant women from the German LiNA cohort were evaluated. The approach allowed the authors to detect and quantify 294 of the 1,199 target chemicals.
They found that each participant harbored a complex mix of organic chemicals, with between 5 and 146 chemicals detected per individual, categorized into six groups: industrial chemicals, pesticides, pharmaceuticals, personal care products, food-related, and endogenous compounds. . Many of the chemicals detected were shown to interfere with neurite development.
Experimental testing of simulated chemical mixtures confirmed that complex chemical cocktails act additively to produce neurotoxic effects, even if concentrations were below the toxic effect thresholds of the individual chemicals. Chemicals attributed to industry and consumer goods were the main drivers of neurotoxic effects in the mixtures.
“These effects do not pose an immediate health concern for pregnant women and their babies. The concentrations we detected reflect typical levels detected in healthy adults around the world; we simply quantified many more chemicals and were therefore able to demonstrate experimentally the hypothetical effects of the mixture,” says Beate Escher, researcher at the Beate I. Escher Helmholtz Environmental Research Center – UFZ and co-author of the study.
“It remains worrying to realize that we find traces of almost all of the persistent chemicals we have produced in the last 100 years, as well as many of the degradable but widely used chemicals today. If we continue to produce and emit chemicals into the current rate, the load of chemical substances will end up increasing until reaching levels that will cause health effects,” concludes the expert.
