From the article:
In postmortem studies, they have also been correlated with death of nigral brain cells – dopamine-producing cells – in patients with Parkinson’s disease.
PCBs were globally manufactured and widely used in the 20th century because the chemicals are stable, heat-resistant and electrically insulating, which made them ideal for use in coolants, flame retardants, lubricants, paints, adhesives and many other industrial products. Because of their toxicity, some countries began banning their use in the 1970s and 1980s, but worldwide production only ended in 2001.
The effect of these toxins continues, McCann says. “The same stability that made PCBs so useful also made them persist in the environment.”
(This may be unpublished work)