Among environmental pollutants heavy metals make up a separate category: contrary to most organic contaminants heavy metals occur naturally, they are persistent, they bio-accumulate and are potentially toxic to man and biota. Metal toxicity can cause very diverse and sometimes baleful effects. Cadmium for example may cause renal dysfunction and respiratory problems in humans and animals. In plants growth retardation occurs as well as root damage, and noxious effects on physiological processes have been observed. Moreover, cadmium is a carcinogen.
algae
