I'm not sure you should specifically be worried about vinyl shower curtains, but vinyl is a specific concern, because to get the form of vinyl that's soft and pliable, the vinyl is mixed about 50/50 with phthalates that are known endocrine disruptors.
That said, phthalates are used in tons of stuff, and it's not fully clear to me which sources are the most important. I've replaced my soap/shampoo/shaving creams with phthalate free versions. It's also present though in basically all plastic tubing, which is known to leach phthalates and is used very extensively in food production machinery.
> I've replaced my soap/shampoo/shaving creams with phthalate free versions
How do you identify these? You mean there are products that advertise themselves to be phtalate free? Or that you are actively looking for phtalate composition in the products you buy?
It will definitely leach from PVC pipe. I'm not sure about PEX. Yes to water dispensers in refrigerators.
In general, the problem will be worse with smaller diameter pipes/tubes due to surface area/volume ratio, worse if the water has been standing in the pipe/tube, and worse if the water is hot.
These chemicals are extremely difficult to get away from. I saw a study where they tried to get volunteers to take a reasonably large set of actions to reduce their levels of BPA and Phthalates, and they were able to get them down to about half the original levels, but not lower.
That said, phthalates are used in tons of stuff, and it's not fully clear to me which sources are the most important. I've replaced my soap/shampoo/shaving creams with phthalate free versions. It's also present though in basically all plastic tubing, which is known to leach phthalates and is used very extensively in food production machinery.