Bioremediation

Metals are common pollutants of water and land because they are emitted by many industrial, agricultural, and domestic sources. In some situations, organisms or ecological processes can be successfully utilized to concentrate metals that are dispersed in the environment, especially in water. The metals can then be removed from the system by harvesting the organisms. For example, metal polluted waste waters can be treated by encouraging the vigorous growth of certain types of algae, fungi, or vascular plants, usually by fertilizing the water within some sort of constructed lagoon. This bioremediation system works because the growing plants and microorganisms absorb metals from the water (acting as socalled biosorbents), and thereby reduce their concentrations to a more tolerable range. The plants can then be harvested to remove the metals from the bioremediation system. In some cases, the plant biomass may even be processed to yield metal products of economic value.