Aquatic Pollution and Coastal Management

Unit 4 : Pesticide pollution

4.12.Biomagnification
Conservative pollutants are not metabolized (broken down inside an organism) and therefore when an organism containing a pollutant is eaten, the pollutants are simply passed on to the predator and accumulate in its tissues. By consuming many preys an organism may build up very high concentrations of the pollutant in its tissues. This process may continue up the foodchain, leaving the top predator with very high and sometimes lethal concentrations of the pollutant. Pollutants will enter organisms via different routes eg. though the mouth and digestive tract or across gill surfaces. Small aquatic organisms absorb most toxins directly from the water whereas carnivores at the top of the food chain - eg. birds and mammals - receive most of their pollutant uptake from their food. Biomagnification occurs across trophic levels.