Other uses of cadmium are as pigments, stabilisers for PVC, in alloys and electronic compounds. Cadmium coatings provide good corrosion resistance, particularly in high stress environments such as marine and aerospace applications where high safety or reliability is required the coating is preferentially corroded if damaged. The most significant use of cadmium is in nickel/cadmium batteries, as rechargeable or secondary power sources exhibiting high output, long life, low maintenance and high tolerance to physical and electrical stress. However, once collected the cadmium is relatively easy to recycle.
In what form is emitted Cadmium?Ĭadmium is produced as an inevitable by-product of zinc (or occasionally lead) refining, since these metals occur naturally within the raw ore. Smoking a packet of 20 cigarettes can lead to the inhalation of around 2-4µg of cadmium, but levels may vary widely. The average daily intake for humans is estimated as 0.15µg from air and 1µg from water. In addition, the metal can be linked to increased blood pressure and effects on the myocardium in animals, although most human data do not support these findings. Cadmium may also produce bone defects (osteomalacia, osteoporosis) in humans and animals. High exposure can lead to obstructive lung disease and has been linked to lung cancer, although data concerning the latter are difficult to interpret due to compounding factors. In humans, long-term exposure is associated with renal disfunction. Cadmium is biopersistent and, once absorbed by an organism, remains resident for many years (over decades for humans) although it is eventually excreted. Effects of Cadmium on the environmentĬadmium derives its toxicological properties from its chemical similarity to zinc an essential micronutrient for plants, animals and humans. Most antimony compounds do not bioaccumulate in aquatic life. There is little information on the effects of long-term antimony exposure, but it is a suspected human carcinogen. Exposure to high levels of antimony for short periods of time causes nausea, vomiting, and diarrhea. It can also be found in batteries, pigments, and ceramics and glass. Effects of Antimony on the environmentĪntimony is a metal used in the compound antimony trioxide, a flame retardant. The three most pollutans heavy metals are Lead, Cadmium, and Mercury. Now we are going to describe the effects of the heavy metals in the environment. Heavy metals can enter a water supply by industrial and consumer waste, or even from acidic rain breaking down soils and releasing heavy metals into streams, lakes, rivers, and groundwater. Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted. Bioaccumulation means an increase in the concentration of a chemical in a biological organism over time, compared to the chemical's concentration in the environment. Heavy metals are dangerous because they tend to bioaccumulate. lead pipes), high ambient air concentrations near emission sources, or intake via the food chain. Heavy metal poisoning could result, for instance, from drinking-water contamination (e.g. However, at higher concentrations they can lead to poisoning. copper, selenium, zinc) are essential to maintain the metabolism of the human body. As trace elements, some heavy metals (e.g. To a small extent they enter our bodies via food, drinking water and air. Heavy metals are natural components of the Earth's crust. Examples of heavy metals include mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), and lead (Pb).
The term heavy metal refers to any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations.
24.243 Classical Set Theory (lecture) (Speech). Handbook of Analysis and Its Foundations.
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