Our cats and dogs, our companion animals, live in our homes, picking up the same chemicals we pick up. If we expect some of those chemicals to affect our health adversely, we can expect to see similar effects in our pets too. Not only that, but as their life spans are shorter (i.e., they age at a faster rate) the endpoints we are concerned with may manifest themselves sooner in our pets than in us.
But first, we need to show that pets actually pick up some chemicals in their systems. Which is what several groups have done in the past. Several more will undoubtedly continue to carry on such work. Read and hear about one such recent effort. [Link]
Never say you can't do something
10 years ago