Contaminants of Emerging Concern in wastewater

Contaminants of Emerging Concern (CECs) are chemicals and toxics that have been found in waterbodies that may cause ecological or human health impacts and are not currently regulated. In wastewater, one of the most common types of CECs are pharmaceuticals and personal care products. Following the Orca Task Force recommendations, we are working to address toxic contaminants in Washington’s water.

Why this matters

There are over 20,000 prescription drugs and personal care products (PPCPs) approved by the Food and Drug Administration (FDA). While these products have a positive impact on quality of human life and provide lifesaving treatments, one unintended result is some of these products are also making their way into Washington’s water. The introduction and accumulation of PPCPs are becoming an environmental concern in the state. Many of them can be toxic to aquatic life and/or bioaccumulate in the food chain, similar to mercury. When exposed to toxic chemicals aquatic life may also experience lethargy, reduced fertility, cancer, and death.

What are they?

Contaminants fall into two general categories: those that are commonly used by people and products used in industry or business.  

Where do they come from?

Many of these products come from human waste. Wastewater Treatment Plants (WWTP) and septic systems were not designed to treat CECs, especially PPCPs. WWTPs were originally designed to handle easily degradable organic material like human waste at high concentrations. CECs tend to be larger, more complex compounds that are found in low concentrations. Traditional treatment may remove some types of CECs from waste; however, there are multiple common CECs that are not removed by standard biological treatment. There are some newer, more advanced treatment technology options that can remove these contaminants.

CECs enter water through wastewater treatment plants (WWTPs) and septic systems in these ways:

  • Direct disposal – People may dispose of products down a household drain. For example, flushing unused pharmaceuticals in the toilet may lead to a high concentration of PPCPs in wastewater.
  • Indirect disposal – CECs enter the wastewater stream due to indirect contact with the substance. For example, microplastics enter wastewater from laundering synthetic material like fleece jackets, microfiber towels, and polyester materials.
  • Excretion – People and livestock consume – then excrete – drugs and their break-down products. The chemicals then get into our wastewater treatment plants, septic systems, and stormwater runoff.

What is Ecology doing?

Washington is one of the first states to try and address this complex issue. With Governor Inslee’s Executive Order and Orca Task Force, one of the recommendations was to address toxic contaminants that bioaccumulate and contaminants of emerging concern.

The Orca Task Force made several recommendations with the goal to reduce the exposure of Southern Resident orcas and their prey to contaminants. 

We prepared a informational paper that gathered and reviewed previously published research results to provide an overview of the science behind removing CECs from wastewater. We reviewed over 280 scientific studies and compiled the results on how effective some wastewater treatment technologies are at removing common CECs. 

In addition, we are working on developing a prioritized list of chemicals of emerging concern that threaten the health of orcas and their prey. We're continuing to work on policy and/or budget requests to prevent the use and release of these chemicals. Additionally, our Safer Products for Washington program aims to reduce exposure to toxic chemicals from consumer products, which can help prevent CECs from reaching the environment. We're also working with our partner agencies and other organizations to discuss and develop a plan to address pharmaceuticals, identify priority actions for source control, and potential wastewater treatment methods. We also periodically review information as new science emerges and adaptively manage the chemical action plans. 

We are working with wastewater treatment plants to remove nutrients from their wastewater. A secondary benefit from removing nutrients is potentially using more advanced treatment technologies that may also remove toxics. Recent advances in treatment technologies have allowed more removal of nutrients and other pollutants of concern that contribute to poor water quality. Advanced wastewater treatment refers to any treatment beyond conventional secondary treatment, such as enhanced nutrient removal, chemical addition, and filtration. 

What can you do to reduce CECs?

The best thing that you can do is learn about what is in your common household products. Many products contain toxic chemicals that make them hazardous — even items you can buy from your local grocery or hardware store. Some of these chemicals require special disposal and should not be discarded down any drain or be put directly into a landfill.

Also, you can make sure to safely dispose of your unwanted over-the-counter and prescription medication, including pet medication. The Dept. of Health Safe Medicine Return webpage has more information. Find where you can drop-off medicine and order free mail-back supplies at or by calling 844-4-Take-Back (844-482-5322).

The best option is to buy safer products

Safer Choice is the U.S. Environmental Protection Agency (EPA)’s product certification and labeling program.

This database includes a list of roughly 2,500 products that EPA certified as safe.

Most of the products listed in the database are for laundry and cleaning, but it also includes products ranging from floor finishes to pet care products.

We also have other helpful information on disposal for different types of waste: