These are metals which are toxic to health and the environment: lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), nickel (Ni), zinc (Zn), manganese (Mn), etc.

Sources

Toxic metals originate from the burning of coal, oil, domestic rubbish ... and certain industrial processes. They are usually found in and on particles (except mercury which is mainly gaseous). The spread of unleaded petrol has considerably reduced concentrations of this pollutant.

Health effects

The metals accumulate in the body and cause toxic effects in the short and / or long term. They can affect the nervous system, renal function, liver, respiratory or others ... 

Effects on the environment

Toxic metals contaminate soil and food. They accumulate in living organisms and disrupt their functional balance and biological mechanisms. Some lichens and mosses are commonly used to monitor metals in the environment and serve as "bio-indicators"..

The reference standards

Lead