Which of the following is a non-essential metal/mineral?

Ans is 'd' i.e. Lead ea Shinde 6/e p533]Lead is not at all an essential mineral; rather it is toxic to the body. (Harrison 17/e Chapter e34. Heavy Metal Poisoning)Harper gives a list of essential minerals along with their functions in the body.Essential minerals and their functionFunctionMineralStructural functionCalcium, magnesium, phosphateInvolved in membrane functionSodium, potassiumFunction as prosthetic groups in enzymesCobalt, copper, iron, molybdenum, selenium, zincRegulatory role or role in hormone actionCalcium, chromium, iodine, magnesium, manganese, sodium, potassiumKnown to be essential, but function unknownSilicon, vanadium, nickel, tinHave effects in the body, but essentiality is not establishedFluoride, lithiumMay occur in foods and known to be toxic in excessAluminum, arsenic, antimony, boron, bromine, cadmium, cesium, germanium, lead, mercury, silver, strontium