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HOST: Today on Diving Deeper Shorts, we revisit our interview on polychlorinated biphenyls, also known as PCBs, from June 2009 with Lisa DiPinto from the Office of Response and Restoration.
Let's listen in.
HOST: Lisa, let's start off with a little more background first on PCBs. Is DDT, another chemical that I think most of us are familiar with, in the same class or category as PCBs?
LISA DIPINTO: Well Kate, DDT and PCBs are actually different chemicals. DDT is a pesticide, where PCBs were developed for a wide range of more industrially oriented applications. But they do have some similarities. They're both presently banned chemicals and they're both very persistent, so we're still finding them both in the environment. From the 1920s until their ban in 1979, there were an estimated 1.5 billion pounds of PCBs that were made for things such as microscope oils, electrical insulators, capacitors, to even electric appliances like old TV sets or refrigerators that we can still occasionally find in households today. They were even sprayed on dirt roads to keep the dust down before they really knew what some of the unintended consequences of widespread use of PCBs were.
HOST: Why do we still study PCBs today if they've been banned since 1979?
LISA DIPINTO: Like so many things in the environment, these chemicals they don't actually breakdown quickly, therefore they don't necessarily disappear once they're banned from use. A lot depends on their chemical makeup - the size and the structure and the chemical composition of the PCBs all that affects how long it takes them to breakdown in the environment. But it can take years to remove these chemicals from the environment and that's why we're still seeing them present decades later.
HOST: Lisa, can we actually see or smell PCBs?
LISA DIPINTO: No, PCBs don't have a known smell or taste. They're typically either oily liquids or sometimes solids and they're colorless or may be a very light yellow in color.
That's all for today's Diving Deeper Shorts, where we highlight a few minutes of your favorite Diving Deeper episodes.
Want to learn more? Go to oceanservice.noaa.gov/podcast.html and select the June 2009 podcast archive to listen to the full interview with Lisa on PCBs.
You can catch the next episode of Diving Deeper Shorts in October.