Toxics in Electronics                                   

In general, computer equipment is a complicated assembly of more than 1,000 materials, many of which are highly toxic. The list of e-toxic components in computers include: 

    Plastics -- PVCs

PVCs are mainly used in computers cabling and housings for its fire retardant properties. However, the initial production and any subsequent incineration of PVC generates dangerous dioxins and furans. Additionally, PVC contaminates other plastics in the recycling process.

Based on the calculation that more than 315 million computers will become obsolete between 1997 and 2004, and that plastics make up over 13 pounds per computer on average, there will be more than 4 billion pounds of plastic present in this computer waste in a couple of years.

    Brominated Flame Retardants

 In computers, brominated flame-retardants (BFR) are used in printed circuit boards, components such as connectors, cables and plastic casing, and PVC coated copper cables and plastic casing.  BFRs in computers, which constitute 25% of all flame retardants produced globally, are a class of brominated chemicals commonly used to reduce flammability and to prevent fires from spreading. They are part of a family of chemicals that have 209 members, two of which are polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDE).

Various scientific observations indicate that polybrominated diphenylethers (PBDE) might act as endocrine disrupters. Research has revealed that levels of PBDEs in human breast milk are doubling every five years. Animal studies have indicated that PBDE can induce neurotoxic effects similar to those caused by other toxic substances such as PCBs and some pesticides. Other studies have shown that PBDE reduces levels of the hormone thyroxin in exposed animals and can cross the blood brain barrier in the developing fetus.

Polybrominated biphenyls (PBBs) may be equally problematic. Researchers in the U.S. found exposure to PBBs may cause an increased risk of cancer of the digestive and lymph systems.

    Lead

The main applications of lead in computers are soldering of printed circuit boards and other electronic components and in glass panels in computer monitors (cathode ray tubes or CRTs).

The effects of lead on human health are well known. Lead was first banned from gasoline in the 1970s. It can cause damage to the central and peripheral nervous systems, blood system, endocrine systems, and kidneys in humans. Lead accumulates in the environment and has a toxic effect on plants, animals and microorganisms.

Consumer electronics constitute 40% of lead found in landfills, creating the potential for leaching and contamination of drinking water supplies. Estimates are that computers discarded between 1997 and 2004 will contain 1.2 billion pounds of lead.

    Cadmium

In electrical and electronic equipment, cadmium occurs in certain components such as certain types of chip resistors, infrared detectors, batteries, and semiconductors. Cadmium is also used as a plastic stabilizer.

Cadmium and cadmium compounds accumulate in the human body, in particular in kidneys. It is adsorbed through respiration and is taken up with food. Due to the long half-life (30 years), cadmium can easily be accumulated in amounts that cause symptoms of poisoning.

    Mercury

It is estimated that 22 % of the yearly world consumption of mercury is used in electrical and electronic equipment. Mercury is used in thermostats, (position) sensors, relays and switches (e.g. on printed circuit boards and in measuring equipment), discharge lamps, batteries, and housing.

Mercury spreads in the water and is transformed to methylated mercury, which easily accumulates in living organisms and concentrates through the food chain (particularly via fish) and can cause chronic damage to the brain.

    Chromium VI (Hexavalent Chromimum)

Some manufacturers still apply this substance as corrosion protection of untreated and galvanized steel plates and as a decorative and hardener for steel housing.

Chromium VI can easily pass through membranes of cells and is readily absorbed producing various toxic effects within the cells. It causes strong allergic reactions even in small concentrations. Chromium VI may also cause asthmatic bronchitis or DNA damage. It is generally agreed that wastes containing chromium should not be incinerated since incineration of hexavalent chromium compounds result in the generation of fly ash from which chromium is leachable.

(Information from  Silicon Valley Toxic Coalition's Just Say No to E-Waste.)

    See also:

Table of Materials in Computers

Clean Computer Campaign/ SVTC Toxics in Computers  (PDF)

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