People by large feels heavy metals are villainous to health. One should take note that for survival human requires heavy metals like iron, zinc, copper, cobalt, molybdenum and also chromium . Most of these are in trace amount needed. People seldom talk about deadly heavy metals like lead, mercury etc. We talk about iron but our body has around 6 gm of iron. We should not equate iron with lead as we do not require it but why talking to industry effluents alone what your water tap pipe contains? what material is used to create a circuit for your mobile phone or TV set ,it is all requires lead and how much we talk about and restricts its use in these highly used equipments?