Arsenic is a trace element found at variable
concentrations in the atmosphere, soils and rocks,
natural waters and organisms.
It is mobilised in the
environment through a combination of natural
processes such as weathering reactions, biological
activity and volcanic emissions as well as through a
range of human activities, including mining, industry
and agricultural use of arsenical pesticides. Of the
various sources of arsenic in the environment,
drinking water poses potentially the greatest threat
to human health
