Cadmium and sewage sludge
This essay concentrates on the heavy metal cadmium, and its occurrence in the environment, its pathways into and out of the human body and its movement into and out of Sewage sludge. Firstly, I will provide a clear definition of the Heavy Metal Cadmium.Cadmium is a naturally occurring element in the earth's crust. Pure cadmium is a soft silver-white metal, but this form is not common in the environment. Rather, cadmium is most often encountered in combination with other elements such as oxygen (cadmium 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 small particles present in air. 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 plating, pigments, batteries, and plastics. Small quantities of cadmium occur naturally 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
Cadmium 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 population 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. ø based on long term airborne concentrations in urban areas. Fertiliser application provides a large percentage of the cadmium present in soils. It is sewage sludge which is one of the most prevalent types of fertiliser in this transfer of cadmium. The remaining 80% originates from industrial sources.
Some common words found in the essay are:
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Approximate Word count = 1223
Approximate Pages = 5 (250 words per page double spaced)
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