A Comprehensive Guide on 1,4-Dioxane Contamination in Drinking Water

What is 1,4-Dioxane?

1,4-dioxane is a colorless liquid primarily used to stabilize various industrial solvents. A highly flammable chemical, its aversion to being absorbed in soil and high solubility in water makes it more widespread in groundwater than similar pollutants. Increased water quality testing nationwide has revealed that 1,4-dioxane contamination is much more prevalent than previously believed.

1,4-Dioxane Sources

Due to the lack of regulation, this chemical has been improperly disposed of for decades, resulting in widespread water contamination. Understanding where 1,4-dioxane contamination comes from can be a critical first step to determining if your community’s drinking water source has been affected.

Industries that commonly use 1,4-dioxane include but are not limited to:

• Pharmaceutical Manufacturing
• Laboratories
• Plastics Manufacturing
• Consumer Products Manufacturing

With these industries in mind, identifying potential 1,4-dioxane sources can help uncover how it impacted your water supply, who your stakeholders are, and the methods necessary to mitigate further contamination. This proactive first step can put your community on a corrective course to reduce consumer 1,4-dioxane exposure and its health effects and prepare your community for potential regulatory guidelines.

How Does It Spread?

A key characteristic that sets 1,4-dioxane apart from other water contaminants is its ability to mix with water in high quantities. While it often leaches into soil initially after disposal, 1,4-dioxane does not interact much with soil or sedimentation.

This stopping point gives 1,4-dioxane two pathways: entering the air as a gas for a short period before degrading in the atmosphere or being soaked up by precipitation and groundwater and entering aquifers where it remains stable indefinitely. These aquifers often supply drinking, irrigation, and industrial process water in communities across the US.

The environmental factors that can affect the speed and concentration of 1,4-dioxane’s spread in groundwater are:

• Soil Permeability
• Aquifer Gradient
• Presence of Other Contaminants

Once arriving in an aquifer, 1,4-dioxane’s ability to quickly dissolve and spread can make its contamination plumes larger and faster spreading than most other water pollutants, complicating treatment. Ultimately, these characteristics make it difficult to control once it reaches your water source.

Bio-persistency

1,4-dioxane is sometimes referred to as a “forever chemical” due to its bio-persistency, meaning it does not readily degrade. While 1,4-dioxane and forever chemicals like PFAS share this bio-persistence trait, 1,4-dioxane’s tendency to break down under certain temperatures, pH, and UV exposure means it is not technically a forever chemical.

However, its solubility and resistance to evaporation make conventional groundwater remediation solutions ineffective. As a result, 1,4-dioxane persists in aquifers for long periods, continuously expanding its plumes and threatening water resources and public health.

While there are commercially available treatment options on the market, they are often expensive to purchase and operate. The chemical’s inclination to spread can also challenge in-situ treatment efficacy, which may force water providers to pick up the slack.

Health Risks Associated with 1,4-Dioxane  2023 EPA Risk Evaluation

The threat of 1,4-dioxane’s bio-persistency and spreadability are compounded by its adverse effects on human and ecological health. In July 2023, the EPA released an updated 1,4-dioxane risk evaluation to supplement its 2020 risk evaluation. In addition to the unreasonable occupational health hazard posed to those in direct contact with the chemical, the updated evaluation found that the general population also faced water and air contamination exposure risks, particularly in fence-line communities.

These communities typically consume 1,4-dioxane via air, water, and food. So, once the compound enters a drinking water source, water utility customers’ daily consumption begins to put them at risk of adverse health effects, such as developing cancer.

Based on these findings, the EPA has proposed to list the presence of 1,4-dioxane in drinking water as an unreasonable health risk, which may change how the Clean Water Act and other federal agencies regulate it. If federal action does occur, water utilities across the US may be required to begin monitoring, reporting, and treating this pollutant to meet Maximum Contaminant Limits (MCLs) aimed to reduce its threat to public health, as we’ve seen with PFAS.

How Does Dioxane Contamination Affect Public Health?

While 1,4-dioxane’s health risks can depend on concentration and timespan of exposure, the compound is known to cause:

• Eye, Skin, and Respiratory Irritation
• Kidney, Liver, and Nervous System Damage
• Kidney and Liver Cancer

Since its health effects have only begun to be studied recently, long-term health effects are not fully understood. However, it has been shown to be particularly damaging to vulnerable individuals such as children, senior citizens, and pregnant people. For example, in pregnant people, there is an elevated risk of still birth rates associated with 1,4-dioxane exposure. The EPA has already reported 1,4-dioxane's effect on American water quality, supplies, and public health. In Ann Arbor, Michigan, the medical filter manufacturer Gelman Sciences discharged 1,4-dioxane into the city’s aquifer from the 1960s until the 1980s. The resulting contamination plume now encompasses an area of approximately one mile wide and four miles long, deeming over 100 private wells and a municipal well unusable. Based on the EPA’s latest health risk evaluation findings, long-time Ann Arbor residents now face higher cancer risks from a lifetime of exposure.

1,4-Dioxane Detection and Monitoring Methods Analytical Techniques

Fortunately, there are ways for communities to detect and monitor 1,4-dioxane in drinking water and wastewater biosolids to better understand its threat level. EPA-approved laboratory Methods 522 and 1602, which use laboratory techniques like solid phase extraction (SPE), mass spectrometry (MS), and gas or liquid chromatography (GC, LC), allow water providers an opportunity to unmask 1,4-dioxane in their water supplies.

1. Method 522: A gas chromatography and mass spectrometry (GC/MS) method whose results are known to be accurate in drinking water and wastewater. The method can detect 1,4-dioxane at levels as low as 0.02 part per billion (ppb), meaning it can read concentrations below state health advisories and New York’s current drinking water MCLs. Some laboratory experts recommend including an “ion trap” in the process to ensure the method’s accuracy.

2. Method 1624: Also a GC/MS-based method, Method 1624 can detect 1,4-dioxane in water, soil, and biosolids. One drawback of this method is that it can only detect 1,4-dioxane at concentrations of 10 ppb or higher. This method is best for testing contamination concentrations in solids.

It’s advised to speak to a water quality expert to determine which method is best for your situation.

Regulations and Compliance

1,4-Dioxane Regulations within the US

The regulatory landscape for 1,4-dioxane is evolving rapidly. 1,4-dioxane has been a topic of conversation in regulatory circles for decades now. As part of the third Unregulated Contaminant Monitoring Rule (UCMR3), talks of regulating 1,4-dioxane on state and federal levels have been ongoing since 2013. The recent publication of the EPA’s 1,4-dioxane revised risk assessment will likely influence further regulatory action at the state level and may lead to further federal action as well.

At the state level, 39 of the 50 states already have an active 1,4-dioxane health advisory in effect. New York State has already established a Maximum Contaminant Level (MCL) for 1,4-dioxane; and other states - including California, New Jersey, Illinois, and Virginia – are also in the process of developing MCLs.

In the meantime, in California, notification and response levels will require water utilities to report 1,4-dioxane concentrations beyond one ppb to their customers, with an obligation to act at levels exceeding 35 ppb beginning in 2024. This early wave of sampling and reporting could increase public awareness in the coming years, potentially with more action on the state and federal levels to follow.

Compliance Challenges and Best Practices

While the equipment to monitor, report, and treat 1,4-dioxane is available, its cost can be a barrier for water providers that are already short on resources. In New York, the passing of 1,4-dioxane MCLs obliged water utilities to:

• Purchase and Operate Advanced Treatment Technology

• Increase Laboratory Budgets for Monitoring and Reporting

• Communicate Health Implications to Customers

• Stay Informed on Regulatory Updates

While states like New York and California navigate 1,4-dioxane regulations, their water utilities may be examples of the best strategies for handling 1,4-dioxane in drinking water.  

These early adopter utilities are:

• Sampling Consistently  

• Identifying Contamination Sources  

• Upskilling Operators

• Engaging Consumers with Action Plans

• Staying Informed on Regulatory Changes

You are not alone if you have questions about how your water system can keep up in a challenging and constantly evolving regulatory environment. To effectively navigate the shifting regulatory landscape, it can be helpful to work with a law firm that has experience in water contamination litigation.

Actionable Steps for Water Utilities

Given the 1,4-dioxane’s potential health impacts and the evolving regulatory landscape, which might require utilities to invest in expensive treatment solutions, water systems should consider taking proactive steps toward preparedness, from understanding risks and potential costs, to seeking funding opportunities.

1. Evaluate You Water Supply [OR Assess Risks]

• If your water system already reported 1,4-dioxane detection or is in an area where 1,4-dioxane has been detected, take immediate action to understand the scope and impact.

• Identify at-risk populations in your community who may be most affected by 1,4-dioxane exposure and prioritize their safety in your planning.

2. Prepare Your Response Plan

• Develop a response plan that addresses 1,4-dioxane contamination risks, incorporating measures for public notification and health advisories based on detection levels. Ensure this plan aligns with regulatory requirements that may mandate or suggest public disclosure and response actions.

• Stay informed about regulatory updates and proactively participate in local and state discussions regarding 1,4-dioxane regulations to ensure your response plan is up-to-date.

3. Secure Funding for Treatment Options

• Plan your budget accordingly to accommodate any necessary water treatment technology that may be required to treat for 1,4-dioxane and emerging contaminants.

• Consider long-term operational costs associated with ongoing monitoring and treatment needs and seek funding opportunities or grants to support these initiatives.

Future Trends and Research

While no one is certain that 1,4-dioxane will follow the same regulatory path as PFAS, the parallels are worth considering. Factors like widespread contamination, potential health risks, and difficulty to treat could mean that 1,4-dioxane will follow in the footsteps that we currently see with PFAS.

As many water utilities benefitted from proactively preparing for the PFAS MCLs and seeking funding for contamination clean-up ahead of time, water providers can begin to do the same as 1,4-dioxane begins to make headlines.

Mitigation Strategies for Dealing with 1,4-Dioxane

Response Protocols

Once detected in a water source, regardless of regulatory standards, preparing a 1,4-dioxane action plan can be vital to managing public perception and the health risks that the chemical poses to drinking water customers. Utilities can begin mitigating the effects of 1,4-dioxane by:

• Continuously monitoring 1,4-dioxane sources to build a data set.

• Speaking with Local Industry to Identify Contamination Sources.

• Devise a Public Communication Strategy for Addressing the Contamination.

• Working with Engineers and Water Professionals to consider treatment technologies.

Water contamination is a complicated issue that warrants a comprehensive approach. By considering each of these factors in your response plan, your utility will be better prepared if 1,4-dioxane becomes a health concern in your community or is regulated by state and/or federal environmental agencies in the future.

Treatment Methods

While conventional drinking water methods can't effectively treat 1,4-dioxane, multiple treatment technologies can remedy the compound and its public health risks. Depending on your utility’s 1,4-dioxane scenario, the following treatment options may be best for you:

1. Advanced Oxidation Processes (AOPs): A group of advanced treatment technologies that combine hydrogen peroxide, UV, and/or Ozone to produce hydroxyl radicals, which break down 1,4-dioxane and many other contaminants. While AOP is energy-intensive, it is currently the most effective method for treating 1,4-dioxane.

2. Activated Carbon: In its various forms, activated carbon is an everyday staple of water treatment plants. And while it has been shown to absorb various levels of 1,4-dioxane, its removal rate is often inconsistent. The removal rate also decreases as the activated carbon becomes saturated.

3. In-Situ Chemical Oxidation (ISCO): ISCO is the process of injecting agents like hydrogen peroxide into a contaminated water source. These chemicals react with and convert contaminants like 1,4-dioxane into less harmful substances that conventional water treatment is better equipped to remove. While this method can replace the need for water treatment plant upgrades, large areas can be challenging to predictably treat and have variable effectiveness.  

Ultimately, if treatment is needed, consulting a professional engineer is the first step to determining which of these methods is appropriate, considering the cause and potential health consequences of your contamination.

Water Contamination Cost Recovery

As the weight of water contamination begins to put pressure on your community, finding the resources to combat it is critical. Here are a few funding routes that are available to water providers to address the cost factors associated with contamination remediation.

Government Awarded Grants

US water providers are encouraged to apply to federal and state grant and loan programs to fund engineering, equipment procurement, and construction costs related to water infrastructure. The recently passed Bipartisan Infrastructure Law (BIL), also known as the Infrastructure Investment Jobs Act, has injected new funding into State Revolving Funds (SRF), EPA grants, and others, making now an opportune time to seek government assistance to manage your community’s water contamination challenges.

1. Drinking Water State Revolving Funds: Individual states and territories administer SRF programs to offer grants and subsidized loans to communities in need of drinking water infrastructure investment. First-time applicants are often prioritized.

2. Geographic Programs: These EPA programs offer additional funding to a diverse set of regions countrywide, from Puget Sound, the Gulf of Mexico, Chesapeake Bay, and many others. If your facility falls in one of the designated regions, this funding may be available on top of traditional SRFs.

3. Superfund Clean-Up: The BIL promises $5.4 billion to firm federal commitment to superfund sites. If 1,4-dioxane contamination has designated your community in proximity to a Superfund Site, there may be federal funding to remedy the contamination.

4. Pollution Prevention Program: While this is for businesses, this funding can be offered to local industry stakeholders to fund their part of remediation if it applies to your contamination incident.

With the guidance of a professional engineer, these and other state and federal funding programs are worth exploring to cover the costs your utility may incur to meet potential 1,4-dioxane regulations.

Increase Rates

Fundraising from ratepayers is the most common way for utilities to cover the equipment, labor, and operational costs that come with water contamination clean-up in water systems. While this may be necessary, despite grants and loans, it often comes with drawbacks:

• Rates Hikes Can Causing Backlash.

• Depending on Community Bylaws, Raising Rates May Be Burdensome.

• Smaller Communities May Not Cover Procurement and Implementation Costs Despite Raised Rates.

• Negative Perception of Utility.

While increasing rates may be an unavoidable part of running your system, finding funding from other sources can be an advisable strategy, as it limits the financial burden on ratepayers.

Litigation

A third funding avenue is litigation. Your community’s contamination has a source, and the polluters responsible did not have the right to contaminate your water sources. Water providers can use the law to seek to hold the chemicals’ manufacturers accountable for the clean-up costs. In the case of past contamination cases, water utilities have successfully won legal decisions that funded their contamination clean-up. Recent examples are the $30.62 million awarded to the City of Pomona, CA to cover its past and future treatment costs for Perchlorate contamination in its water sources; the $816 million awarded to the State of New Hampshire for MTBE water contamination; and the $10.3-12.5 billion PFAS settlement from 3M, which will allocate funds to water utilities affected by PFAS contamination.

When considering law firms to represent your utility, you may want to prioritize attorneys with extensive water contamination litigation experience and that work on a contingency fee basis, ensuring no litigation costs are incurred unless a favorable outcome is outreached, thus limiting the risk for your water system and your ratepayers. This could be the most effective way for your utility to recover the costs of contamination.

Taking Action to Mitigate 1,4-Dioxane Contamination

Taking a proactive stance to 1,4-dioxane water contamination, involving comprehensive communication strategies, identifying suitable treatment options, and seeking cost recovery strategies to mitigate treatment costs, can be incredibly beneficial.  

Having helped over 150 clients recover more than $1.2 billion through settlements and trials since 2003, SL Environmental Law Group is vastly experienced with water contamination litigation and has the in-house knowledge to keep you updated on upcoming regulation and the potential impact for your system. Our firm operates on a contingency fee basis, ensuring no upfront litigation costs for water systems and their ratepayers. If you are interested in evaluating cost recovery strategies for 1,4-dioxane water contamination, schedule a free consultation with SL Environmental today.