Excess presence of which one of the following in drinking water can elevate the blood pressure of humans?

Excess lead in drinking water can raise human blood pressure and cause other serious harm.

Sulphate in excess mainly causes a laxative effect, not raised blood pressure.

Zinc in excess affects taste and can upset the stomach, not blood pressure in this way.

Copper in excess can harm the liver and cause nausea, but is not the classic pressure-raising contaminant here.

Lead is a cumulative toxin that damages the nervous system and kidneys as well.

Old lead pipes and solder are a common source of lead in tap water.