Pollutants in shallow marine sediments
Above: Near a river mouth, pollutant metals adsorb to the surface of iron sulfide minerals. Frequent mixing of oxygen and sediment-plus high amounts of oxygen and low amounts of organic debris-cause the metal pollutants to be easily released into an aqueous phase.
Below: In a ship's channel, the environment's low supply of oxygen, abundant organic debris and infrequent mixing cause the pollutant metals to co-precipitate with iron sulfide minerals. The stable mixture is slow to release pollutants into an aqueous phase.
