In the natural state, the volcanic emissions
maintain 90% the arsenic discharges. It is also in almost all natural metal sulphides. The
emissions, due to the human activity, come from the coal burning and the fuel which reject
a considerable quantity in the environment.
The total arsenic discharge is 35.3 million
kg in water.
All the
compounds are toxic but the inorganic forms are particularly pernicious and it is
especially in watery ecosystems they represent a danger. Once transformed by bacteria and
yeasts into gas derivative like the dyméthylarsine, they accumulate in the marine flora,
the algae in particular concentrate arsenic 1000 to 10 000 times.
