Emerging Contaminant Manufacturers and Landfill Leachate Pollution

We typically don’t think twice when we toss a candy wrapper into a trash can. If you live in the US, that candy wrapper is likely transported to a nearby landfill to keep our streets, lakes, and homes trash-free. Unfortunately, after being buried, hidden chemicals lurking within trash can sometimes find their way out into the environment.

Researchers and environmental agencies are tracking a startling trend. Manufacturers sometimes use dangerous chemicals such as PFAS and 1,4-dioxane, considered likely carcinogens by the EPA, in their products. These manmade chemicals are biopersistent, meaning they do not break down easily over time and are highly mobile in the environment. At the end of these products’ life cycle, they are sent to landfills. There, rainwater soaks in and mixes with decaying garbage to produce "leachate” that may be contaminated with the chemicals. Because manufacturers never warned consumers or landfill operators of the risks of PFAS or 1,4-dioxane, no precautions could be taken to keep these products out of unlined landfills. As such, contaminated leachate has leaked from some active and retired unlined landfills into surrounding soil, surface, and groundwater for decades, contaminating water sources relied on by farms, cities, and industrial applications nationwide.

Although landfill operators treat their leachate and monitor surrounding groundwater to prevent contamination, standard treatment methods cannot remove emerging contaminants like PFAS and 1,4-dioxane. As a result, these chemicals continue to seep into our soil, slowly traveling to the water table. This phenomenon impacts the water quality of privately owned wells, farm irrigation, and community water providers that depend on groundwater to meet their needs. The result is widespread contamination that poses serious public health risks and financial burdens to clean what was once considered safe drinking water.

How Landfills Affect Groundwater Contamination

Americans have relied on modern landfills to store their refuse since 1937, marked by the opening of the first landfill in Fresno, California. Alongside the Clean Water and Safe Drinking Water Acts, the EPA developed standards for American landfills in the 1970s under the Resource Conservation and Recovery Act (RCRA) that include siting restrictions, surface and groundwater protection, and disease control measures.

In 2018, Americans generated an estimated 292.4 million tons of municipal solid waste. That’s almost five pounds daily per person. Our throw away habits may be why Nevada hosts the world’s largest landfill, the Apex Regional Landfill. Apex has a surface area of 1,400 football fields or 80,640,000 square feet and is designed to hold one billion tons of compressed trash.

As rain and groundwater infiltrate landfills, the resulting leachate may carry contaminants from the discarded items inside. If manufacturers have used hazardous substances in those products, such as  organic and inorganic compounds, heavy metals, and chemicals like 1,4-dioxane, then the leachate may also contain those substances.  Concerningly, when manufacturers fail to warn consumers and users that these items belong only in hazardous waste landfills, contaminated leachate may escape the confines of the landfill. Continuing through the soil, it may travel into aquifers and nearby streams, rivers, and lakes, damaging aquatic ecosystems and drinking water quality.

Despite RCRA guidelines and potential upcoming PFAS-in-leachate regulations, the volume of landfills in the US challenges efforts to eliminate leachate contamination. The US has ~2,000 active and 10,000 defunct landfills scattered across the country. Since PFAS and 1,4-dioxane have been found in products for decades, some landfills that are no longer in use may contain many of these items. Landfill operators were never warned to keep such products out of their facilities, and it is nearly impossible to retroactively remove them. Therefore, despite operators’ best efforts, contaminated leachate may continue spreading into nearby soil, ground and surface water.

The Challenges of Emerging Contaminants at Landfills

Across the country, landfill operators have faced significant challenges in managing emerging contaminants like PFAS and 1,4-dioxane, which were not widely known or regulated when many landfills were initially constructed. Landfills were built under the assumption that the materials they accepted, though subject to general waste management regulations, would not pose long-term environmental risks. Unfortunately, the discovery of these persistent chemicals, which do not break down over time, has caught many landfill operators off guard.

When leachate—the liquid that forms as rainwater or groundwater passes through decaying waste—was found to be contaminated with chemicals like PFAS and 1,4-dioxane, operators were often shocked. These chemicals, which were not identified as hazardous during the early years of the landfills’ operations, are now known to be dangerous and have been linked to a variety of health issues. The realization that these chemicals were present in landfill leachate created an unforeseen burden for operators who had been doing everything right according to the regulations of the time.

In response, many landfill operators have had to invest heavily in advanced treatment technologies to deal with contamination. However, these costs were not anticipated, as the presence of these chemicals was not known when the landfills first began operation. This issue has been seen in landfills across the country, including both active and closed sites, highlighting how operators can be blindsided by the emergence of contaminants that they had no way of predicting.

The situation demonstrates how, despite following established waste management practices, landfill operators may find themselves responsible for costly remediation efforts due to the presence of emerging contaminants. As awareness of the risks posed by chemicals like 1,4-dioxane continues to grow, more landfill operators are now faced with the complex task of managing leachate that may carry these harmful substances.

The Cost of Contamination

Fortunately, there are treatment technologies and innovative practices that inform how to collect and treat leachate containing organics, metals, and chemicals like 1,4-dioxane. However, they’re expensive to purchase and operate. For communities and individuals that rely on groundwater, the water treatment solutions required will increase the cost of historically affordable water sources.

Despite the fact that they do not produce or profit from emerging contaminants, community water providers will likely be made responsible for keeping their drinking water free of the pollutants found in leachate. While there are federal grants and initiatives available to cover some of the associated costs, communities and utilities can consider litigation as an option to fund these upgrades and keep polluters accountable.

As stories like Casella’s Bethlehem landfill continue to gain national attention, more communities may begin investigating whether landfill leachate has been contaminated by dangerous products lacking proper disposal protocols. If your community suspects landfill leachate contaminated with 1,4-dioxane or PFAS has affected your groundwater, you can learn more by visiting our  Guides Page. Learn how your water system can begin finding solutions today.