Impact on Society, Environment, and Human Health

Upsides to PCBs
Ever since its inaugural commercial production in 1929, the production of PCBs in the early twentieth century boomed like the Klondike Gold Rush. According to an American chemical engineer in the 1930s, PCBs were "as perfect as any industrial chemical can be." Why? Because of its convenient physical and chemical properties. As previously noted, this alleged ‘Wonder Bread’ of chemicals exhibits low flammability, low reactivity, and low electrical conductivity. PCBs also have a high heat capacity.

This set of handy characteristics therefore makes PCBs useful for all kinds of products. Up until 1977, PCBs had been widely sought after for residential, commercial, and industrial applications.

Below: an electrical transformer

Before PCB production was banned, you would've found them:
- as insulating fluids and coolants in heavy machinery, like electrical transformers, motors, and hydraulic systems
- thermal insulation material for fiberglass, felt, foam, and cork
- as plasticizers in paints, plastics, and rubber - pigments and dyes
- in carbonless copy paper (shown on the right)
- in fire-retardant materials
- in adhesives and sealants

More specifically, Askarel is a PCB-rich electrical insulating material which generates non-explosive gaseous mixtures when decomposed. Vintage fluorescent light ballasts (the electrical components at the end of fluorescent light fixtures, shown in the image below) may still contain PCBs.

Without PCBs, technological development in the 1920s and 1930s would have trudged at a much slower pace.

Nowadays, the products listed above are made with PCB-alternatives. These alternative chemicals will be covered in the next section.

Left: fluorescent light ballasts


But wait...
When something is described to be “perfect”, you know it’s too good to be true. The properties which make PCBs useful to society also make them dangerous for our health and the environment.

PCBs enter the environment in the form of landfill leachate, leakage from electrical transformers, or combustion gases during waste incineration.

The non-explosive properties of PCBs may work wonders for fire prevention, but their inability to biodegrade allows these compounds to spread through the atmosphere and waterways like forest fire. It’s estimated that 150 million pounds of it are dispersed in the natural environment. PCBs also last for a long period of time; their average half-life is eight to fifteen years.

If you also take into consideration the high solubility of PCBs in fats and oils, you’ll understand why they readily dissolve and settle in the fatty tissues of animals. Toxic effects on wildlife are the consequence.

In turn, when humans eat fatty foods like eggs, fish, and dairy products, bioaccumulation occurs, and PCBs end up being absorbed in our liver and adipose tissues. The provisional tolerable daily intake for PCBs, set by Health Canada, is 1 microgram per kilogram of bodyweight per day. In comparison, our average daily dietary intake of PCBs is just 0.5 micrograms, but there are still detectable traces of it in our bodies.


Human health effects
The International Agency for Research on Cancer ruled PCBs as “probably carcinogenic”. Significant research has also been conducted on the non-cancer implications of PCB exposure.

Here is a table I created to summarize the human non-cancer health effects:
One of the most notorious PCB-contamination incidents occurred in Japan in 1968; it’s now known as the “Yusho” incident. Rice bran oil contaminated with PCB fluids made 1,300 citizens ill. After ingesting 0.5 to 2 grams of this fluid, they developed severe skin eruptions, eye discharge, jaundice, and edema.

Although that incident happened halfway around the world over a century ago, the residents of the Great Lakes are facing a smaller scale of Yusho today. Research by the Great Lakes Centers showed that Great Lakes fish and their offspring have suffered health effects due to PCB-contamination. Thus, when residents at the top of the food chain consume fish such as carp and salmon, bioaccumulation occurs once again.

Right: chloracne, a severe skin
eruption associated with PCB
exposure

Above: bioaccumulation in the food chain

Now can't you see why PCBs had been banned?