I had heard that leaving your plastic water bottles in direct sunlight leaches toxic chemicals out into the water. But, now I see just leaving the water in a hot car, whether or not it's in direct sunlight, leaches dioxin into the water, a chemical found increasingly in breast cancer cells. Dioxin is also the chemical found in bleached paper products.
Many have heard of these solutions, but they are worth repeating:
1) Don't buy water in plastic bottles. Federal Law requires the water to be boiling when putting the water into the bottle which already starts the chemical-leaching process.
2) Buy your own BPE-free water containers and purchase water from a water store.
3) Carry your water in a stainless-steel, glass, or a BPE-free container and don't leave it in a hot car.
4) Don't freeze water in plastic bottles. Freezing also allows dioxin to be released into the water as it thaws.
5) Don't microwave in plastic, styrofoam, or cardboard containers. Put food into a glass bowl or on a glass plate to cook or reheat. You just don't know what's in those containers.
6) Buy a raised microwave plate cover to place over your food in the microwave when using. If you cover the plate with plastic wrap or paper towel, don't it touch the food.
Going on a detoxification program from time to time is a good way to decrease your body's toxic load!