Summary: A new study links quat-based cleaners to neural tube defects in mice. They also discovered mice do not need to be dosed with the chemicals for the effects to show in their offspring, being in the environment where the cleaners were administered was enough to illicit an effect.
Source: Virginia Tech.
A new study at the Edward Via College of Osteopathic Medicine (VCOM) and the Virginia-Maryland College of Veterinary Medicine at Virginia Tech has found a connection between common household chemicals and birth defects.
Known as quaternary ammonium compounds or “quats,” the chemicals are often used as disinfectants and preservatives in household and personal products such as cleaners, laundry detergent, fabric softener, shampoo and conditioner, and eye drops. The research demonstrated a link between quats and neural tube birth defects in both mice and rats.
“These chemicals are regularly used in the home, hospital, public spaces, and swimming pools,” said Terry Hrubec, associate professor of anatomy at the VCOM-Virginia campus and research assistant professor in the veterinary college’s Department of Biomedical Sciences and Pathobiology. “Most people are exposed on a regular basis.”
Hrubec investigated the effect of two commonly used quats: alkyl dimethyl benzyl ammonium chloride and didecyl dimethyl ammonium chloride. These are often listed on ingredient lists as ADBAC and DDAC, respectively, and are valued for their antimicrobial and antistatic properties, as well as their ability to lower surface tension. Hrubec found that exposure to these chemicals resulted in neural tube birth defects — the same birth defect as spina bifida and anencephaly in humans.
“Birth defects were seen when both males and females were exposed, as well as when only one parent was exposed,” said Hrubec, who is first author on the study and holds both a doctor of veterinary medicine degree and Ph.D. from the Virginia-Maryland College of Veterinary Medicine. “The fact that birth defects could be seen when only the father was exposed means that we need to expand our scope of prenatal care to include the father.”
Hrubec found that mice and rats did not even need to be dosed with the chemicals to see the effect. Her research shows that simply using quat-based cleaners in the same room as the mice was enough to cause birth defects. “We also observed increased birth defects in rodents for two generations after stopping exposure,” Hrubec added.
An earlier study in Hrubec’s laboratory found that these chemicals led to reproductive declines in mice. Follow-up research found that quats were decreasing sperm counts in males and ovulation in females. The research raises the possibility of quats contributing to human infertility, which has been on the rise in recent decades.
“We are asked all of the time, ‘You see your results in mice. How do you know that it’s toxic in humans?'” Hrubec said. “Our research on mice and rats shows that these chemicals affect the embryonic development of these animals. Since rodent research is the gold standard in the biomedical sciences, this raises a big red flag that these chemicals may be toxic to humans as well.”
Quaternary ammonium compounds were introduced in the 1950s and 1960s before the standardization of toxicity studies. Chemical manufacturers conducted some toxicity studies on the compounds during this period, but they were never published. Today, the chemicals are regulated by the U.S. Environmental Protection Agency.
Hrubec noted that an epidemiological study could determine whether people who have a high rate of exposure, such as healthcare workers or restaurant servers, have a more difficult time becoming pregnant or have a greater likelihood of having children with neural tube birth defects, but no such study has been conducted to date.
Funding: In addition to VCOM and the veterinary college, the study received funding from the Passport Foundation, a San Francisco-based nonprofit that sponsors research on product safety.
Source: Michael Sutphin – Virginia Tech
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Original Research: Full open access research for “Ambient and dosed exposure to quaternary ammonium disinfectants causes neural tube defects in rodents” by Terry C. Hrubec, Vanessa E. Melin, Caroline S. Shea, Elizabeth E. Ferguson, Craig Garofola, Claire M. Repine, Tyler W. Chapman, Hiral R. Patel, Reza M. Razvi, Jesse E. Sugrue, Haritha Potineni, Geraldine Magnin-Bissel, and Patricia A. Hunt in Birth Defects Research. Published online June 15 2017 doi:10.1002/bdr2.1064
Ambient and dosed exposure to quaternary ammonium disinfectants causes neural tube defects in rodents
Quaternary ammonium compounds are a large class of chemicals used for their antimicrobial and antistatic properties. Two common quaternary ammonium compounds, alkyldimethylbenzyl ammonium chloride (ADBAC) and didecyldimethyl ammonium chloride (DDAC), are combined in common cleaners and disinfectants. Introduction of a cleaner containing ADBAC+DDAC in the vivarium caused neural tube defects (NTDs) in mice and rats.
To further evaluate this finding, male and female mice were dosed in the feed at 60 or 120 mg/kg/day, or by oral gavage at 7.5, 15, or 30 mg/kg ADBAC+DDAC. Mice also received ambient exposure to ADBAC+DDAC from the disinfectant used in the mouse room. Embryos were evaluated on gestational day 10 for NTDs, and fetuses were evaluated on gestational day 18 for gross and skeletal malformations.
We found increased NTDs with exposure to ADBAC+DDAC in both rats and mice. The NTDs persisted for two generations after cessation of exposure. Notably, male exposure alone was sufficient to cause NTDs. Equally significant, ambient exposure from disinfectant use in the vivarium, influenced the levels of NTDs to a greater extent than oral dosing. No gross or significant axial skeletal malformations were observed in late gestation fetuses. Placental abnormalities and late gestation fetal deaths were increased at 120 mg/kg/day, which might explain the lack of malformations observed in late gestation fetuses.
These results demonstrate that ADBAC+DDAC in combination are teratogenic to rodents. Given the increased use of these disinfectants, further evaluation of their safety in humans and their contribution to health and disease is essential.
“Ambient and dosed exposure to quaternary ammonium disinfectants causes neural tube defects in rodents” by Terry C. Hrubec, Vanessa E. Melin, Caroline S. Shea, Elizabeth E. Ferguson, Craig Garofola, Claire M. Repine, Tyler W. Chapman, Hiral R. Patel, Reza M. Razvi, Jesse E. Sugrue, Haritha Potineni, Geraldine Magnin-Bissel, and Patricia A. Hunt in Birth Defects Research. Published online June 15 2017 doi:10.1002/bdr2.1064