1,4-Dioxane, a highly mobile compound found in various manufacturing processes and consumer products, has drawn significant attention recently. Classified by the United States Environmental Protection Agency (USEPA) as “likely to be carcinogenic to humans” by all routes of exposure, its properties present challenges for characterization and treatment – sparking concerns about its potential impact on human health and the environment.
What is 1,4-Dioxane?
A volatile, flammable liquid, 1,4-dioxane is a man-made organic compound. Its high mobility in soils and rapid migration in groundwater, coupled with its resistance to subsurface biodegradation, pose environmental challenges. While it shares similarities with “forever chemicals” like PFAS, 1,4-dioxane does not bioaccumulate in plants or animals over time, distinguishing it from true “forever chemicals.”
Industrial Applications and Consumer Products
Since the 1950s, 1,4-dioxane has primarily been used as a stabilizer in industrial solvents. While restrictions in drinking water, groundwater, and other environmental regulations have impacted industrial reliance on 1,4-dioxane, it is currently still in use in certain manufacturing processes – including:
- Solvent for paper, cotton, and textile processing
- Chemical manufacturing and stabilizing in chlorinated solvents
- Solvent for paints, dyes, greases, antifreeze, and aircraft deicing fluids
- Pesticide solvent or inert ingredient
- Additive in adhesives
- Solvent in the manufacture of pharmaceuticals, veterinary drugs, and natural health products
- Carrier for biocides; to analyze vegetable matter, dehydrate biological samples prior to slide preparation, and isolate DNA elements
- Byproduct in the manufacture of polyethylene terephthalate (PET) plastic
However, 1,4-dioxane’s presence is not confined to industrial settings. It has been detected as an impurity or trace contaminant in various consumer products – primarily cosmetics and detergents. But many companies have been actively working to reduce this impurity in recent years.
Exposure
The primary exposure pathways for 1,4-dioxane are inhalation, ingestion, and dermal exposure.
Occupational contact and exposure are most likely to occur at manufacturing facilities. People can
be exposed following ingestion or contact with water containing 1,4-dioxane and with cosmetics/
personal hygiene products that contain ingredients in which it may be a contaminant.
Short-term exposure may cause eye, nose, and throat irritation; large quantity short-term exposure may lead to kidney and liver damage. Acute exposure to large amounts of 1,4-dioxane has been associated with adverse nervous system effects and can result in death.
Chronic exposure has shown liver and kidney damage in animals. Laboratory animal studies have also shown that oral exposure over a lifetime causes cancer, while skin exposure can also increase the cancer-causing properties of other chemicals.
Health and Environmental Concerns
Due to its high solubility in water and mobility in soils, one concern associated with 1,4-dioxane is its potential to be a contaminant in groundwater and drinking water. The compound has been identified in water supplies in various regions, leading to worries about its potential effects on public health. Prolonged exposure to elevated levels of 1,4-dioxane in drinking water may pose health risks – making it a subject of close scrutiny by regulatory agencies worldwide. USEPA has set guidelines for acceptable levels in drinking water to ensure public safety.
Regulatory agencies and environmental organizations – such as USEPA, the Occupational Safety & Health Administration (OSHA), and the Food and Drug Administration (FDA) – closely monitor and regulate the levels of 1,4-dioxane in water supplies; work environments; and food, cosmetics, and household products to ensure public safety. In order to limit the inadvertent release of this chemical into the environment, it’s important for industries to implement proper waste disposal practices – including proper wastewater treatment and containment measures to prevent its migration into groundwater.
The Environmental Working Group, the Centers for Disease Control, and the FDA emphasize the importance of raising awareness about 1,4-dioxane and advocating for responsible manufacturing practices. By encouraging the reduction or elimination of this compound in industrial processes, companies can contribute to a healthier and more sustainable environment.
The EPA, OSHA, and other state environmental agencies can also encourage limiting the use of this compound by enforcing more stringent actionable levels in air, water, and soil. For example, USEPA performed a Risk Evaluation in 2020 and drafted a supplement in July 2023 as part of the amended Toxic Substances Control Act (TSCA).
Consumer Awareness and Product Choices
Consumers can also play a crucial role in mitigating the impact of 1,4-dioxane. By being
informed about product ingredients and choosing items with lower or no levels of this compound,
individuals can make choices that align with their health and environmental values. Many
companies are now recognizing the importance of transparency in labeling and are working to
reduce or eliminate 1,4-dioxane from their products.
Treatment Technologies
Since being identified as an emerging contaminant of concern, several technologies have been utilized to remediate 1,4-dioxane with varying results. The removal of 1,4-dioxane by conventional water and wastewater treatment plants has proven to be ineffective due to its unique physicochemical properties. 1,4-dioxane dissolves completely and does not evaporate readily, making it difficult to remove from water.
Wastewater and drinking water treatment plants across the U.S. have needed to implement new techniques to meet the increasingly strict standards as new information about the effects of this compound are discovered. Common treatment technologies include advanced oxidation processes (AOPs) and bioremediation. In situ and ex situ bioremediation processes are being explored as more cost-effective, but time-consuming, remediation techniques.
Ongoing Research and Future Outlook
As the scientific community continues to study 1,4-dioxane, ongoing research aims to deepen our understanding of its behavior in different environments and its potential long-term effects. This knowledge will be instrumental in shaping regulations and industry practices to minimize the risks associated with this compound.
In conclusion, while 1,4-dioxane has widespread industrial applications, its presence in consumer products and potential impact on water supplies have raised valid concerns. Regulatory measures, responsible manufacturing practices, and informed consumer choices are essential in addressing these concerns and working towards a safer, healthier future.
How HETI Can Help
HETI’s staff of environmental scientists, geologists, industrial hygienists and remediation professionals have extensive experience in evaluating sites for potential 1,4-dioxane contamination. We coordinate/conduct soil and groundwater sampling and assess specific needs to bring sites to federal/state regulatory compliance – working with our clients in the development of various remedial approaches. Whatever the issue, HETI is here to help.