Why is milk given to someone who accidentally ingested a heavy metal?

Milk acts as a buffer for the heavy metal and surround the heavy metal and negate or neutralize the effect of the metal ion .

Explanation:

Heavy metals are associated with the poisoning in humans such heavy metals are lead, mercury, and other metals. Milk plays the role of a buffer against the heavy metals in the body of humans.

Milk surrounds the heavy metal like mercury or other and neutralize it by making a buffer to it and relax intoxicate the effect of the heavy metal ion.

Thus, the correct answer is - Milk acts as a buffer for the heavy metal and surround the heavy metal and negate the effect of the ion.