Arsenic and water: reaction mechanisms, environmental impact and health effects

Arsenic can be found in seawater (2-4 ppb), and in rivers (0.5-2 ppb). Half of the arsenic present is bound to particles. Freshwater and seas algae contain about 1-250 ppm of arsenic, freshwater mycrophytes contain 2-1450 ppm, marine molluscs contain 1-70 ppm, marine crustaceans 0.5-69 ppm, and fishes 0.2-320 ppm (all values are based on dry mass). In some marine organisms, such as algae and shrimp, arsenic can be found in organic compounds.
The legal limit for arsenic in water applied by the World Health Organization (WHO) is 10 μg/L.