Cadmium And Sewage Sludge :: essays research papers

Cadmium and sewage sludgeThis essay concentrates on the heavy surface candela, and its occurrence in the environment, its pathways into and out of the human bole and its movement into and out of Sewage sludge. Firstly, I will provide a clear definition of the Heavy Metal Cadmium.What is Cadmium?Cadmium is a natur eachy occurring element in the earths crust. Pure standard candle is a soft silver-white metal, but this form is not common in the environment. Rather, certificate of deposit is most often encountered in combination with other elements such(prenominal) as oxygen ( certificate of deposit oxide), chlorine (cadmium chloride), or sulphur (cadmium sulphide). These compounds are all stable solids that do not evaporate, although cadmium oxide is often found as part of wee particles present in striving.Most cadmium is obtained as a by-product from the smelting of zinc, lead or copper ores. Cadmium has a number of industrial applications, but it is used mostly in metal platin g, pigments, batteries, and plastics.Cadmium in the EnvironmentSmall quantities of cadmium occur by nature in air, water, soil and food. For most people, food is the primary source of cadmium exposure, since food materials tend to take up and retain cadmium. For example, plants take up cadmium from soil fish take up cadmium from water, and so on.It is introduced into the environment from mining and smelting operations. Other cadmium emissions are from fossil render use, fertilizer application, sewage sludge disposal or galvanized pie corrosion. The largest source of these cadmium releases into the general environment is the burning of fossil fuels (such as coal or oil) or the incineration of waste materials. Cadmium may also escape into the air from zinc, lead or copper smelters. Working in or donjon close to a major source of airborne emissions such as these may result in higher than average exposure. Pathways into the human physical structureFood and DrinkCadmium can enter the blood by absorption from the stomach or intestines after ingestion of food or water. The amount of Cadmium ingested by an individual within a macrocosm can differ greatly due to dietary habits. For example, an individual who consumes a large amount of brown crabmeat or vegetables grown on land which is fertilised with sewage sludge are likely to have intakes of cadmium significantly above the average population level.Only a small percentage of cadmium ingested with the food intake is absorbed, approximately 6%. tho there are many factors, which can affect this figure, namely, physiological, such as age and the content of the diet.