When I dig up the soil and drink water from it, I’m pretty sure that I’m going to be sick because of all the bacteria, pollutants and chemicals in this water. I can’t drink tap water, river water, or even the rainwater where I live for this reason, too.
However, somehow when I take water from these sources and feed it to my plants, I can trust that the water I will consume later when I eat the fruits or leaves (in the case of vegetables) from these plants will be safe for me. Why is that?
I guess what I hope to know is: When plants take water from the underground, where do all the bacteria, pollutants and chemicals go? Are they filtered by the root and stem of the plant? Or are they “killed” by some kind of immune system that the plants have?
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EDIT: Thank you everyone for answering. I did not expect so many replies, I think I understand this topic much more now. I used to think that water in fruit is always sterlized and completely safe to drink, but apparently that is not the case.
A lot of comments also asked where I live that I cannot even drink tap water straight from the faucet. It is my understanding that in Europe and North America, tap water is often safe to drink, but that is not the case at all in many developing countries. In fact, I remember being VERY surprised when I first saw American people drinking from fountains in parks or filling up a glass of water straight from the kitchen sink in Hollywood movies.
I live in Vietnam. The tap water here mostly comes from rivers, and it undergoes all the filtration and chemical treatment that we can give it, but we are still recommended to at least boil the water first before drinking.
When I was a kid, we did not even have a system to deliver tap water to every homes, even in the capital city (Hanoi). That was as recent as the early 2000s, (I was born in 1993), and most people used to drink and cook using either water from well or collected rainwater. But nowadays, many wells in my city are found to have lead, arsen and heavy metals in it, and rainwater is recently reported as unsafe to drink basically anywhere on Earth because it had “forever chemicals” in it that will never decomposes and can cause cancer. Tap water and bottled water are basically our only options, though the goverment still recommend boiling tap water or at least filter it one more time before drinking/cooking with it.
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The opening for nutrients to get into plants through the roots is small and thus only elements and small molecules like water, nitrate ions, and lead can get in through this path. Bacteria and viruses are A LOT bigger and can’t get in. However, lead, and many other metals that can get in such, as cadmium, aluminum, copper, arsenic and iron. Some of these are needed, just like your body need iron, and some aren’t and cause known health problems in humans.
It is worth noting that the plants aren’t absorbing chunks of metal. The metal is in the form of single atoms, typically with a net charge as an ion, in the soil and can thus be taken up with the water.
So the bacteria stay in the soil. Some of the pollutants can be absorbed, with smaller stuf consisting of only a few atoms more likely to be absorbed.
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