PBT photo identifier


What are Persistent, Bioaccumulative Toxics (PBTs)?

The goal of Ecology's PBT initiative is to reduce and phase-out the use, release, and exposure to PBTs in Washington in order to reduce and eliminate threats to human health and the environment.

Persistent, bioaccumulative toxics (PBTs) are a distinct group of chemicals that threaten the health of people and the environment. Examples of PBTs include methylmercury, PCBs, DDT and dioxin. These types of toxic chemicals are considered the "worst of the worst" and raise special challenges for our society and the environment because:
Bioaccumulation of PCBs

Bioaccumulation of PCBs
(Image courtesy of Seattle Post Intelligencer)

  • They remain in the environment for a long time without breaking down (persistent).
  • Animals and people accumulate PBTs in their bodies. As these chemicals move up the food chain, they increase in concentration, and linger for generations in people and the environment (bioaccumulate).
  • Exposure to PBTs has been linked to a wide range of toxic effects in fish, wildlife, and humans, including effects on the nervous system, reproductive and developmental problems, immune-response suppression, cancer, and endocrine disruption (toxic).
  • PBTs can travel long distances and generally move easily between air, water and land, spanning boundaries of programs, geography, and generations.
Some PBTs have been banned for more than 30 years, but their presence remains in land and water across the globe. In Puget Sound, for example, the PCBs in sediment build-up in Orca whales and other marine life. Another example is DDT, which is still found in Washington soils more than 30 years after the pesticide DDT was banned by EPA.

How is Ecology addressing PBTs?
Ecology published our Strategy to Reduce PBTs in December 2000. After working with an advisory committee and getting input from the public, the PBT Rule was published in January 2006. The PBT rule includes PBT criteria and a list of PBTs that meet these criteria, as well as procedures to periodically update the list. The focus of our work on PBTs is preparing and implementing Chemical Action Plans (CAPs). The PBT rule describes the parts of a CAP, how CAPs are developed, and how PBTs are chosen for a CAP.