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Why e-waste is considered hazardous waste

Computers and other electronic equipment are manufactured from natural as well as man-made materials. While some naturally occurring substances, such as chromium, are relatively harmless in nature, their use in the manufacture of electronic equipment often results in compounds which are toxic being especially harmful to human health and the environment if not disposed of carefully.

Arsenic is a poisonous metallic element which is present in dust and soluble substances. Chronic exposure to arsenic can lead to various diseases of the skin and decrease nerve conduction velocity and can cause lung cancer.

Barium is a metallic element that is used in sparkplugs, fluorescent lamps and “getters” in vacuum tubes. Being highly unstable in the pure form, it forms poisonous oxides when in contact with air. Short-term exposure to barium could lead to brain swelling, muscle weakness, damage to the heart, liver and spleen.

Beryllium has been classified as a human carcinogen since exposure to it can cause lung cancer. The primary health concern is inhalation of beryllium dust, fumes or mist. Workers who are constantly exposed to beryllium, even in small amounts, and who become sensitised to it can develop chronic beryllium disease (beryllicosis) - a disease which primarily affects the lungs. Exposure to beryllium causes a form of skin disease that is characterised by poor wound healing and wart-like bumps. Studies have shown that people can still develop beryllium diseases many years after the their last exposure.

Brominated flame retardants (BFRs) - the three main types of BFRS used in electronic and electrical appliances are polybrominated biphenyl, polybrominated diphenyl ether and tetrabromobisphenol - A BFRs have been found in indoor dust and air through migration and evaporation from plastics. Combustion of halogenated case material and printed wiring boards at lower temperatures releases toxic emissions including dioxins which can lead to severe hormonal disorders. Major electronic manufacturers have begun to phase out BFRs because of their toxicity.

Cadmium components may have serious impacts on the kidneys. Cd is adsorbed through respiration and taken up with food.

Due to the long half-life in the body, cadmium can easily be accumulated in amounts that cause symptoms of poisoning. Acute exposure to cadmium fumes causes flu-like symptoms of weakness, fever, headache, chills, sweating and muscular pain. The primary health risks of long term exposure are lung cancer and kidney damage.

CFCs (chlorofluorocarbons) are compounds composed of carbon, fluorine, chlorine, and sometimes hydrogen. Used mainly in cooling units and insulation foam, it has been phased out because when released into the atmosphere, it accumulates in the stratosphere and has a deleterious effect on the ozone layer, which results in an increased incidence of skin cancer in humans and in genetic damage to many other organisms.

Chromium and its oxides are widely used because of their high conductivity and anti corrosive properties. While some forms of chromium are non toxic, Chromium (VI) is easily absorbed in the human body and can produce various toxic effects within cells. Most chromium (VI) compounds are irritating to eyes, skin and mucous membranes. Chronic exposure to chromium (VI) compounds can cause permanent eye injury, unless properly treated. Chromium VI may also cause DNA damage.

Dioxins and furans are a family of chemicals comprising 75 different types of dioxin compounds and 135 related compounds known as furans. “Dioxins” refer to the family of compounds comprising polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. Although never intentionally manufactured, dioxins form as unwanted by-products in the manufacture of some pesticides as well as during combustion. They are known to be highly toxic to animals and humans because they bio-accumulate in the body and can lead to malformations of the foetus, decreased reproduction and growth rates and impairment of the immune system,among other things.

Lead is the fifth most widely used metal after iron, aluminium, copper and zinc. It is commonly used in the electrical and





in solder, lead-acid components, cable

sheathing, in the glass of CRTs, etc. Short-term exposure to high levels of lead can cause vomiting, diarrhoea, convulsions, coma or even death. Other symptoms are appetite

loss, abdominal pain, constipation, fatigue,





Continued excessive exposure, as in an industrial setting, can affect the kidneys.

It is particularly dangerous for young children because it can damage nerves and cause brain and blood disorders.

Mercury is one of the most toxic yet widely used metals in the production of electrical and electronic applications. It is a toxic heavy metal that bioaccumulates causing brain and liver damage if ingested or inhaled. In electronics and electrical appliances, mercury is concentrated in batteries, some switches and thermostats, mercury vapour

and fluorescent lamps.

Polychlorinated biphenyls (PCBs) are a class of organic compounds use in a variety of applications, including dielectric fluids for capacitors and transformers, heat transfer fluids and as additives in adhesives and plastics.

PCBs have been shown to cause cancer in animals and a number of serious non- cancer health effects in animals, including effects on the immune system, reproductive system, nervous system, endocrine system

and other health effects. PCBs are persistent contaminants in the environment.

Due to the high lipid solubility and slow metabolism rate of these chemicals, PCBs accumulate in the fat-rich tissues of almost all organisms (bioaccumulation). The use of PCBs is prohibited in OECD countries, however, due to its wide use in the past, it still can be found in e-waste and in some other wastes.

Polyvinyl chloride (PVC) is the most widely- used plastic, used in everyday electronics and appliances, household items, pipes, upholstery etc. PVC is hazardous because it contains up to 56% chlorine which when burned produces large quantities of hydrogen chloride gas, which combine with atmospheric moisture to form hydrochloric acid which when inhaled, leads to respiratory problems.

Selenium exposure to high concentrations of selenium compounds cause selenosis.

The major signs of selenosis are hair loss, nail brittleness, and neurological abnormalities (such as numbness and other odd sensations in the extremities). Source: www.ewaste.ch

October 2006 - EngineerIT

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