PBTs (persistent, bioaccumulative toxins)
PBTs are both naturally occurring and man-made substances that build up in the food chain and can affect human health and reproduction. These toxins travel long distances in the atmosphere, move readily from land to air and water, and do not break down easily.
The use of some persistent toxins, such as PCBs, has been banned for more than 30 years, although their presence remains in land and water across the globe. Good cleanup technologies don’t yet exist for addressing PCB contamination in water. In the Puget Sound, for instance, PCBs in sediment build-up in orca whales and other marine life.
Federal initiatives by the U.S. Environmental Protection Agency recommend phasing out the use or production of PBTs.
In Washington state, mercury has been identified as the most widespread and potentially harmful PBT, prompting legislation to develop and implement mercury reduction strategies.
How can PBTs harm us?
PBTs are associated with damage to the nervous and reproductive systems of humans and other animals, and they can cause developmental and learning problems in children. PBTs have a unique ability to affect the brain, central nervous system, eyes and other organs of developing fetuses. PBTs can also affect motor abilities.
Why is mercury the state’s first PBT priority for action?
Mercury is the highest priority because of its widespread use and ease of release into the environment.
What else is being done about PBTs?
Reducing and preventing pollution - particularly persistent toxins - can and is occurring through a variety of ways:
- Further development of alternative materials used in products and industrial or manufacturing processes.
- Incremental, continuous improvements in pollution reduction through better science and processes, technical assistance and the use of regulatory tools.
- Additional guidance and direction to agencies by Washington's Legislature.
Why not simply ban all PBT emissions and discharges outright?
PBTs are produced from a wide variety of sources, and it would be virtually impossible to impose use bans for some of them. These include vehicles powered by internal combustion engines, pharmaceuticals, some household appliances, and the presence (due to historical use) of pesticides and PCBs in sediments and tissues. In some cases, small amounts of PBTs are produced from naturally occurring events like forest fires. The best approach for the immediate future will be to look at the diverse sources and destinations of each of the PBT chemicals and use that information to tailor chemical-specific reduction strategies.
For more information visit Washington State Department of Ecology’s PBT Strategy.