Some essential micronutrients such as arsenic are primarily sourced from water. You don’t need much so most natural sources contain enough. There is actually a valid concern that obsessive over-purification of drinking water can lead to deficiencies of some trace minerals.

Wow this has gone off the rails quickly.

To wit: Arsenic is not an essential micronutrient.

"Trace quantities of arsenic have been proposed to be an essential dietary element in rats, hamsters, goats, and chickens. Research has not been conducted to determine whether small amounts of arsenic may play a role in human metabolism." [1]

[1] https://en.wikipedia.org/wiki/Arsenic

There is substantial evidence that arsenic is a required micronutrient in all mammalian biology. This is not even controversial, you can reliably induce deficiency syndromes in a broad spectrum of animal models, and the operative pathways exist in humans. The effect was first observed in animal husbandry in parts of the world with very low background arsenic levels.

It has the same toxicity and micronutrient profile as selenium, another extremely toxic but nonetheless essential micronutrient. Unfortunately, activists with an unrelated agenda have been spreading unscientific misinformation about arsenic to advance that agenda.

Same story as fluoride outrage actually. Being anti-science is fashionable and most people are ignorant about chemistry.

It is one thing that makes me glad I am no longer a practicing chemist.

If what you are saying is true – and I am not being sarcastic - I encourage you to edit and update the Wikipedia page that I referenced.

The authority that I have appealed to (Wikipedia) is a reasonable one and bias should not be implied in the absence of these supposed corrections you have to make.

I’m open-minded …

A tertiary source aims to be non-authoritative. Wikipedia tries pretty hard at it.

Eat a serving of rice, preferably American, without rinsing it.

Enjoy your 10000% recommended daily intake of Arsenic.

Background levels are much higher than current standards with no observable effects in many parts of the world. This is well-studied. There is a threshold but it is higher than people assume.

Plant-based arsenic often has poor bioavailability. Quite a few plants people eat are natural accumulators but it just passes through. Pesticides and geology are the primary bioavailable sources.