Occurrence and transformation of arsenic in the marine environment.

Among the trace elements, arsenic appears to possess a unique position in the environment. When comparing terrestrial and marine organisms there seems to be a significant difference between both level and chemical forms of arsenic. The level of arsenic in terrestrial organisms is seldom above 1 ppm (dry material) whereas the corresponding values for marine organisms vary from several parts per million up to more than 100 ppm. Furthermore, results so far show that marine organisms are able to convert inorganic arsenic into organic arsenic compounds. No evidence points to a corresponding ability in the terrestrial ones. In the aquatic organisms the arsenic is present as both lipid soluble and water soluble compounds. The water-soluble organic arsenic compounds have a basic character and are very stable to chemical and metabolic breakdown.