What are PBTs and Bioaccumulative Susbtances?
- Persistent: Decompose very slowly in water and soil
- Bioaccumulative: Accumulate in living organisms
- Toxic: Pose the risk of cancer, mutations, reproductive issues, or other adverse health effects
What is Bioaccumulation?
Bioaccumulation is when a chemical gradually builds up in the system of an organism.
For example, if plankton absorbs chlorinated water, the concentration of chlorine in its system will gradually increase. The animals that eat that plankton will also accumulate chlorine, and the concentration will increase the higher the animal is on the food chain. Consequently, even if the initial concentration of chlorine wasn’t very harmful, a bioaccumulative substance could have devastating effects on humans and the ecosystem over time.
Which Bioaccumulative Substances are Restricted?
Persistent Organic Pollutants (POPs)
Persistent organic pollutants are a class of PBTs that’s largely made up of halogenated organic molecules. They often come from pesticides, industrial processes, and combustion.
POPs are very bioaccumulative substances. Because halogenated compounds are soluble in lipids, they get readily absorbed into fatty tissue.
In addition, an especially harmful aspect of POPs is their volatility. They evaporate readily from soil and plants – rarely degrading in the atmosphere due to their stability. As a result, they can travel to remote places like the Arctic, harming both the wildlife and the indigenous peoples that hunt for food.