Scientists Detect Common Fungicide in Pregnant Women and Children
UNC-Chapel Hill scientists led by Mark Zylka, PhD, found measurable levels of a biomarker for azoxystrobin in pregnant women and young kids, and investigated the fungicide’s ability to pass from mothers to embryos in utero in mice and during lactation.
The agricultural industry began using AZ and related strobilurin-class fungicides in the mid-1990s, and usage has increased exponentially to 1,000 tons applied to vegetable, nut, potato, fruit and grapevine crops in the United States, as well as to cereals and turf grass. AZ has been found in large amounts in surface water due to agricultural runoff. It is known to be harmful to aquatic life and invertebrates.
Later, AZ was added to specific brands of mold and mildew-resistant wallboards, now commonly used in residential and commercial construction.
In the past decade, several experimental studies found AZ has the potential to cause developmental toxicity and neurotoxicity. In cortical neuron cultures prepared from embryonic mice, AZ induced reactive oxygen species (free radicals) that can damage cells. In zebrafish, AZ altered cell death-related gene expression in larvae and caused oxidative stress in larvae and in adults. Following parental AZ exposure in zebrafish, a significantly higher incidence of mortality and malformations was observed in offspring.
These studies suggested that AZ is toxic at embryonic stages, and as a result of these studies, scientists identified it as a major front-line target chemical for biomonitoring in the United States. Yet, there isn’t much information about whether humans – especially young children and pregnant mothers – are exposed to detrimental amounts of AZ, or whether the fungicide can be transferred from mother to embryos, and if so, what are the health ramifications.
Zylka’s lab conducted experiments, led by first author Wenxin Hu, PhD, a UNC-Chapel Hill postdoctoral researcher, to measure the concentration of a biomarker of AZ exposure (AZ-acid) in the urine of pregnant women and in a separate group of children ranging from 40 to 84 months old. AZ-acid was present in 100% of the urine samples from pregnant women and in 70% of the urine samples from children, with median concentration of 0.10 and 0.07 ng/mL (nanograms per milliliter) and max concentration of 2.70 and 6.32 ng/mL, respectively.
Experiments further revealed that AZ crossed the placenta and entered the developing brain of mouse embryos, and AZ transferred to offspring during lactation.
“Azoxystrobin has been detected in house dust, with some samples showing high concentrations,” Zylka said. “Our current research shows that azoxystrobin is being metabolized by humans, which means humans are ingesting it. Some of the children had persistently high levels of the metabolite, suggesting they are chronically exposed to azoxystrobin. This fungicide is on-track to become as prevalent in the home as other chemicals like pyrethroids, plasticizers, and flame retardants. We urge the scientific community to ramp up efforts and determine if chronic exposure to azoxystrobin affects humans during fetal development and after birth.”
Other authors of this paper are Chih-Wei Liu, Yun-Chung Hsiao, Kun Lu in the UNC Department of Environmental Health Sciences at the UNC Gillings School of Global Public Health; Jessica A. Jiménez in the Curriculum in Toxicology & Environmental Medicine; Eric S. McCoy at the UNC Neuroscience Center the UNC Department of Cell Biology and Physiology; Weili Lin, director of the UNC Biomedical Research Imaging Center and the UNC Department of Radiology in the UNC School of Medicine; and Stephanie M. Engel in the UNC Department of Epidemiology at Gillings.
Funding for this research came from the Simons Foundation, The National Institute of Environmental Health Sciences (NIEHS, R35ES028366; P30 ES010126), the National Institute of Mental Health (U01MH110274), and a Gillings Innovation Laboratory award from the UNC Gillings School of Global Public Health.
Environmental Health Perspectives published this companion piece to the peer-reviewed scientific paper led by the Zylka lab.
From UNC Health and UNC School of Medicine Newsroom
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