I'll start with water. Here in Toronto, we've been sampling from some local plants. Our water is drawn from the Great Lakes, so the source of the microplastics in that water is simply the microplastics being in the lake. People also have sampled bottled water and have found microplastics in that bottled water. Some of that is actually from the PET cap. In groundwater, people find that there's much less.
I think it just depends on where you're actually getting your water from and where your water is stored. Also, then, we're trying to understand if anything is added during the treatment process.
For air, microplastics are found now to be prevalent in dust. I think some of this is the waste issue we're discussing, but some of it is just the fact that I'm sitting in a room with plastic chairs and plastic-made carpets. If the sun were shining in a window, I could see little dust particles floating around. The reality is that some of those are from the materials in the room. When we look at a certain type of instrument to tell what type of material it is, we see that some of those are microplastics. Because they're getting airborne, they are transporting atmospherically, like other chemicals.
That's why, when we think about solutions, we have to think about this whole circular economy and waste issue. For microplastics, some things are a bit unique, in that some of this just comes from the wear and tear of using the materials. Tire dust is another example of that.