Unraveling 1,4-Dioxane: Sources, Spread, and Financial Impact

Unraveling 1,4-Dioxane: Sources, Spread, and Financial Impact

After eating at your favorite restaurant, your plates are typically taken away and cleaned in the kitchen to serve the next customer. This involves washing oils and fats down the drain. To avoid fines, restaurants often rely on grease traps and trash collectors to prevent these fats, oils, and grease from entering and harming public sewers.

But what if that grease found its way into the sewer despite the restaurant catching and paying for grease disposal? Suppose the waste management company’s grease treatment goes wrong and unintentionally disposes of it in the sewer.

The unfortunate fact is that this chain of events can often lead to contamination pathways opening for chemicals like  1,4-dioxane, despite a facility’s best effort to mitigate this result.

Identifying and addressing 1,4-dioxane pollution is a growing challenge for utility and business leaders. This colorless, water-soluble chemical is a pervasive pollutant, often dubbed a “forever chemical” due to its resistance to conventional water treatment methods and persistence in groundwater.

EPA monitoring under the Third Unregulated Contaminant Monitoring Rule (UCMR3) detected 1,4-dioxane in approximately seven percent of sampled public water systems across the United States (based on data collected from 2013 to 2015). This same testing data only detected PFAS in just over one percent of sampled public water systems. This widespread contamination has the potential to lead to similar regulatory momentum for 1,4-dioxane as we’ve seen with PFAS.

1,4-Dioxane Uses/Applications

Dioxane production exploded in the 1980s when it was used to stabilize the active chemicals found in aluminum aerosol can products, particularly 1,1,1-Trichloroethane (1,1,1-TCA). While the Montreal Protocol banned 1,1,1-TCA, 1,4-dioxane’s ability to prevent corrosive chemicals from reacting with their surroundings and its high solubility in water has made it attractive to many industrial applications.

Industrial Solvent Applications

Solvents are used to dissolve, extract, or stabilize other substances, and 1,4-dioxane’s unique chemical properties make it especially valuable in this context. In chemical manufacturing, dioxane stabilizes volatile, chlorine-based solvents, ensuring their safe use and storage. In food processing, its solvent properties aid the extraction of oils (think vegetable oil) and enhance the stability of food packaging materials.

Pharmaceutical Manufacturing

1,4-dioxane is a preferred solvent for pharmaceutical production and stabilizing chemical reactions. Its properties make it invaluable for:

• Stripping Impurities: Used to cleanse medical and veterinary pharmaceuticals, 1,4-dioxane helps achieve the high purity standards required in medicine production.

• Accelerating Reactions: 1,4-dioxane supports the efficient mixing and reaction of active ingredients during the production of complex chemical formulations.  

• Research Applications: Laboratories employ 1,4-dioxane as a reagent in developing and testing new pharmaceuticals.

Detergent Manufacturing

In addition to intentional production, 1,4-dioxane is sometimes a byproduct of ethoxylation. Ethoxylation is used to create the ingredients that improve the cleaning power of household soaps and detergents. However, this process can inadvertently produce 1,4-dioxane as an impurity. Despite ongoing efforts by manufacturers to reduce its occurrence, 1,4-dioxane persists in household products such as:

• Laundry Detergents: Ethoxylated surfactants remain a common ingredient in these household essentials.

• Dishwashing Liquids: Trace amounts of 1,4-dioxane can be found in formulations designed for grease-cutting and heavy-duty cleaning.

• Personal Care Products: Items like shampoos and body washes also sometimes contain residual 1,4-dioxane.

The FDA monitors 1,4-dioxane levels in these products, noting progress in reducing its unintended presence. However, its continued detection underscores the challenges in fully eliminating this contaminant.

The reliance on 1,4-dioxane in these critical applications showcases its usefulness but also highlights the many pathways for contamination, as waste from pharmaceutical, chemical, and soap manufacturing, among others, can inadvertently introduce the chemical into water bodies and ultimately impact human health.

Environmental and Health Impacts

The extensive use and persistence of 1,4-dioxane has created widespread contamination of water sources. Its classification as a likely human carcinogen raises urgent concerns for public health and the environment.

Health Risks Associated with 1,4-Dioxane

Prolonged exposure to 1,4-dioxane has been linked to several adverse health effects. Infants, pregnant women, and individuals with compromised immune systems are particularly at risk from 1,4-dioxane exposure, even at lower concentrations.

• Carcinogenic Potential: The EPA estimates that daily consumption of 1,4-dioxane-contaminated water poses a cancer risk for the public. Animal studies reinforce this, showing higher rates of tumors in the liver, gall bladder, and nasal cavity with continued exposure​.

• Short-Term Effects: Acute exposure to high levels of the chemical can result in drowsiness, headaches, nausea, and irritation of the eyes and respiratory tract.

• Organ Damage: Long-term exposure is associated with liver and kidney damage and potentially the nervous system.

Environmental Challenges of 1,4-Dioxane Contamination

While sunlight quickly destroys 1,4-dioxane and the chemical minimally reacts to soil, 1,4-dioxane’s high solubility helps it readily infiltrate and stay in aquifers. Once it enters aquatic systems, it can travel long distances and persist for decades. In addition to groundwater contamination, rivers and streams are affected by wastewater discharges containing 1,4-dioxane, continuously contaminating aquatic ecosystems and drinking water sources. 1,4-dioxane also resists traditional drinking water treatment methods, such as activated carbon filtration. Furthermore, PFAS treatment systems that many agencies are working to get established for remediation are not effective in treating 1,4-dioxane detections.

Direct Pollution Sources: Regulated but Widespread

Direct 1,4-dioxane pollution stems from its use and production in industrial processes, where the chemical is often discharged as a byproduct or waste. Historically, industrial facilities were the most prominent contributors to 1,4-dioxane contamination due to insufficient regulations and disposal practices. These untreated discharges typically occurred at chemical manufacturing plants, dumping 1,4-dioxane into nearby rivers and streams. These point-source discharges created contamination hotspots, with nearby groundwater supplies and surface water bodies receiving high concentrations of dioxane.

The Legacy of Unregulated Discharges

Despite regulatory momentum, the environmental legacy of 1,4-dioxane continues to haunt communities. Industrial sites that operated for decades without pollution controls left behind plumes of contamination in soil and groundwater. Cleanup efforts at these legacy sites often require costly remediation techniques like advanced oxidation processes (AOPs) or pump-and-treat systems to extract and degrade dioxane from aquifers. Some contaminated areas qualify for federal cleanup under the EPA’s Superfund program.

Direct pollution from 1,4-dioxane has become a cautionary tale about the importance of proactive environmental management. While regulations now limit future discharges, the lingering impacts of past industrial activities underscore the need for continued monitoring and remediation efforts.

Indirect Pollution Sources: Persistent and Less Controlled

While direct industrial discharges of 1,4-dioxane are often the focus of contamination discussions, indirect pollution sources play an equally significant role in its impact. These secondary pathways, such as leachate from landfills, septic systems, and aging infrastructure, contribute to the widespread presence of this persistent contaminant in groundwater and drinking water systems.  

Once 1,4-dioxane enters groundwater or surface water from these secondary pathways, its high solubility and resistance to natural degradation enable it to persist for decades. Indirect contamination typically occurs when products containing trace amounts of 1,4-dioxane are discarded or improperly managed. Over time, these products degrade, releasing 1,4-dioxane into the environment.  

• Groundwater Contamination from Landfills: Landfills receive consumer waste, such as personal care products and detergents. As these products decompose and mix with rainfall, they generate leachate, a liquid byproduct that carries dissolved chemicals into groundwater supplies.  

• Septic Systems: Household products containing 1,4-dioxane can pass through septic systems untreated in rural areas. The contaminant then seeps into the surrounding soil and eventually infiltrates groundwater.

• Leaking Sewer Lines and Infrastructure Failures: Aging sewer infrastructure can allow dioxane-laden wastewater to escape into the environment through soil and water systems.

Studies show that 1,4-dioxane is present in up to 70% of landfills handling incinerator waste and 38% of those managing other types of waste​. For communities relying on groundwater for drinking water, the implications are severe. Contaminated aquifers require advanced and costly remediation techniques to reduce 1,4-dioxane to safe levels. These challenges underscore the need for robust waste management practices and infrastructure upgrades to minimize indirect pollution sources.  

Key Differences in Impact and Regulation

Over the past decades, regulatory frameworks have emerged to limit direct discharges of 1,4-dioxane. These efforts have significantly reduced the volume of 1,4-dioxane entering the environment from direct industrial discharges. However, historical contamination remains a pressing concern.

• EPA Guidelines: Between 2013 and 2015, the EPA monitored dioxane at water treatment plants under the Unregulated Contaminant Monitoring Rule (UCMR).

• State-Level Regulations: States have begun to establish specific drinking water standards, starting with New York’s strict 1 part per billion limit, prompting industrial compliance measures​. Several other states have already begun the process of creating MCLs as well.

• Industrial Wastewater Permits: Many facilities now operate under permits that require the use of advanced treatment technologies to remove contaminants like 1,4-dioxane from their effluent.

While the environmental and health impacts of 1,4-dioxane are similar regardless of its source, the pathways require distinct mitigation strategies. Direct pollution can be more easily identified and regulated due to its point-source nature. In contrast, indirect pollution can be more challenging to address, as it involves diffuse sources and often lacks clear accountability.

Both pathways ultimately contribute to the persistent challenge of 1,4-dioxane in drinking water, but addressing indirect pollution requires stronger infrastructure investments and improved waste management practices. For communities and utilities, tackling direct and indirect sources is critical to ensuring safe, clean water supplies.

The Path to Effective Mitigation

We live in a contaminated world where pollution sources are rarely straightforward, complicating the work of government and business leaders. However, understanding the pathways that pollutants like 1,4-dioxane take to enter our water can simplify the unknown and equip these leaders with the first steps to tackling their water contamination problem.

Regardless of whether water contamination is direct or indirect, the remediation process can be costly and upend plans. Read our 1,4-dioxane resource hub today to learn more about how to approach water contamination step by step.