system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can juicy fruits like watermelon be grown in regions of the world that have horrible water pollution, but it doesn't seem to affect the people who eat it?
gpt
Plants absorb water through ultra-fine membranes made of plant tissue. Some chemical pollutants can indeed get in and poison the plant. But the most common pollutants we worry about in our water -- things like bacteria -- are way too big to make it in through that membrane.