Heavy metal is a term used to describe a subset of a large number of metals and metalloids with high atomic(such as chromium, cadmium, arsenic, and mercury), listed in the periodic table of the elements, which have properties of both metals and non-metals. The heavy metals, which include copper (Cu), zinc (Zn, lead (Pb), mercury (Hg), nickel (Ni), cobalt (Co), and chromium (Cr), are common trace constituents in the earth crust. Since the industrial revolution has the density of heavy metals in the ambient environment increased dramatically, to most people’s concern. Many of these metals are important and play a role in human physiology, nevertheless. These are very small amounts that also exist in nature compared to the high levels. The never-ending demand for more raw materials to build cars, ships, houses. Consumer goods have been taken out of Earth’s crust where they were stored naturally, however, instead of returning them back or recycle for new products they have been left everywhere, and with time erode polluting water, soil, and air. Heavy-metal contamination is widely spread, mostly lead and mercury. Because of our civilization car culture, the use of leaded gasoline has caused global pollution in the most pristine environments, from arctic ice fields to The Himalayas. See Petroleum.
Sources and further reading: Pollution A to Z / Richard Stapleton, editor in chief. 1. Pollution—Encyclopedia
ECO-FASHION-DENIM AND DIAGRAMS DICTIONARIES OVERVIEW