It's finally looking like summer in most of the northern hemisphere and heat waves and sunny days are the norm.
Lots of warning are being issued regarding hydration and drinking enough of water while out and about - and that's definitely sound advice.
However, let us not forget that most of the water that we consume (or drinks in general) come in bottled form and mainly - in plastic containers.
Keep in mind that the plastic material used for bottles is a 'cost-effective' one which basically means that it is not particularly free from toxic substances like the Ines belonging to the dioxin group.
This is not ideal for bottled water in general, but becomes especially dreadful when the bottles are heated - in the car, in the direct sunlight, in the microwave. The intoxication of the water in the bottle with dioxins is fast and the effect of it on the body is that of a neurotoxin, a carcinogen and an endocrine disruptor.
So it is wise to keep yourself hydrated, it is even wiser to make sure your water comes from glass bottles, and if bottled in plastic - never heat it and don't drink from the bottles left in the car.