My personal opinion is mandated flame retardants in foams, mattresses and cushions and other plastics. Smokers die less from fire but everybody else breath poison.
That said, the pop media (of which Scientific American is part) routinely conflates rates of diagnosis with rates of late-stage cancer, even though they're very different, and there's a discrepancy between them. I don't know about colon cancer in particular, but I know that it's been a long-term trend in many different cancers -- for example (iirc) skin cancer -- that people are getting diagnosed far more often, but death rates due to the illness are essentially constant.
This tells you either that we're getting worse at treating what we diagnose, or more plausibly, that we're not detecting things that would lead to death.
Why not microplastics, fine particle pollution, noise (urban living around lots of cars and/or heavy industry), mental stress, lack of sleep, lack of healthy connections, lack of time outdoors and healthy exercise, and similar things?
Seems weird to me to pick one arbitrary class of chemicals when all of the things I listed have been worsening.
[..] pesticides, GMOs, the flood of chemicals approved for everyday use, ranging from "soaps" to perfumes, to indoor "purifiers" etc, ultra-processed foods, and the list goes on.