Among all the metal elements, cadmium is one of the most harmful elements that pose the greatest threat to human health. Cadmium is harmful to human tissues and organs in many ways, mainly to the kidneys and liver.
The second group of harmful substances - lead
Lead is a heavy metal element that is harmful to the nervous system. Severe lead poisoning can cause children to become imbeciles or even die.
The third group of harmful substances-mercury
Mercury poisoning can lead to significant memory loss, lack of concentration, and generalized weakness.
The fourth group of harmful substances-hexavalent chromium
Chromium causes various inflammations and is also a carcinogen.
The fifth and sixth hazardous substances-PBB & PBDE
PBB & PBDE can cause thyroid hormone disorders and malformation of the fetus and other hazards.
I. Cadmium in electronic products:
Cadmium metal or powder can be used as a cathode electrode material in nickel-cadmium (NiCd) batteries. Can also be used with iron, steel, aluminum-based materials, titanium-based alloys or other non-ferrous alloys, as in electrolytic deposition, vacuum deposition or mechanical deposition when the coating. In addition, it is also used as an alloying element in low melting point hard solder, soft solder and other special alloys.
Harmful effects of cadmium:
Since the discovery of adverse effects on human health in Japan in the 1950's and 1960's (aches and pains), the effects of cadmium on health and the environment began to be widely discussed. One of the most notable effects is that occupational exposure of workers to high concentrations of cadmium-containing fumes or dust with suspended particles affects the kidneys and respiratory system. The most thoroughly researched human health effect is kidney failure, caused by prolonged exposure to high doses. Therefore, most developed countries have set occupational exposure standards for cadmium between 2mg/m3 and 50mg/m3 in the atmosphere, which can protect the human body with a normal working life of 40 to 45 years.
Prohibited range:
In order to reduce the exposure of workers to cadmium, to ensure that cadmium-containing products to minimize the exposure and risk to consumers, in European countries, cadmium and certain cadmium-containing products by the EC Directive 76/769/EEC, 91/338/EEC, 91/157/EEC and the 1989 European Executive Committee Cadmium Action Plan to limit. Sweden, Denmark, the Netherlands, Switzerland, Austria and Norway also in the EC restriction of cadmium-containing products such as pigments, stabilizers and paints (91/338/EEC) before the implementation of cadmium-containing products control. But at present, in addition to the EU countries, there is no other country in the world on the control of cadmium-containing products.
RoHS:
The directive regulates electrical and electronic equipment that must not contain cadmium since 2008.
Except for the following
Cadmium oxide on the surface of selenium photovoltaic cells
Cadmium passivation metal used for corrosion prevention in specific articles
Heavy metals lead, cadmium, and mercury are used in hollow cathode tubes for atomic absorption spectrometers and other heavy metal measurement equipment
TCO'01-Mobile Phones:
Cadmium content in cell phones should not be greater than 5ppm.
II. Uses of lead in electronics:
Batteries, solder, alloying elements for mechanical metals, printed circuit boards and related components, white hot bulbs, lead hammers.
Lead Hazards:
Lead metal processes may produce lead compounds, all of which are categorized as hazardous substances, with varying toxic effects. In humans, lead affects the central nervous system and kidneys. The environmental toxicity of lead to a number of organisms is well established. Blood lead concentration of 10?g/dl or more will produce sensitive biochemical effects, if long-term exposure to blood lead concentration of more than 60~70?g/dl will cause clinical lead poisoning. Lead surfaces react easily in air, soil and water to form a layer of protective and insoluble inorganic lead compounds. These inorganic compounds have a low bioavailability and are usually absorbed by terrestrial plants and animals only at high concentrations. However, lead does not biomagnify in terrestrial or aquatic food chains.
Ban range:
Lead recovered from waste electrical and electronic equipment is identical to lead from virgin minerals, so it should be possible to confine lead to a closed loop. However, the current rate of lead recovery from waste electrical and electronic equipment is limited by the recycling rate of the waste rather than by technical barriers. Based on the toxicity of lead compounds to humans and the environment, the production, use, recycling and disposal of lead must be legislated to limit its environmental release; and the extent to which human exposure can be tolerated must also be regulated. In general, much is known about the risks associated with the use of lead, and there is extensive legislation in place, for example, for oils, water pipes, etc., to ensure that human health and the environment are protected. As a result, incidents of lead poisoning in most countries have declined dramatically over the past 20 years, and lead levels in the environment are often well below recommended values. In addition, lead is fully recyclable and can be used forever in electrical and electronic equipment.
RoHS:
The directive regulates electrical and electronic equipment that must not contain lead as of 2008.
Except for the following
The heavy metal lead is used in radiation or radiation-protective equipment
Lead is used in CRT glass, light bulbs and fluorescent tubes
Lead is used in steel up to a maximum of 0.3% by weight, aluminum up to a maximum of 0.4% by weight, and copper up to 4% by weight
Pb is used in electronic devices. p>Lead is used in ceramic parts in electronic devices
Heavy metals lead, cadmium and mercury are used in hollow cathode tubes in atomic absorption spectrometers and other heavy metal measurement equipment
The lead content in batteries, paints, lacquers, wires and plastics in cell phones cannot be greater than 10 ppm.
Thirdly, mercury is used in electronic products. The use of mercury in electronic products:
Measurement and control instruments, batteries, light sources and electrical equipment, dental industry, chlorine production equipment (amalgam electrolysis process).
Hazards of Mercury:
Mercury is classified as a hazardous substance, an inhalant poison and has bioaccumulative effects. Mercury is also highly toxic to aquatic organisms. Its effects on humans are mainly on the central nervous and renal systems. It has the potential to convert to organic mercury under certain environmental conditions, resulting in enhanced toxic properties. Mercury has a remarkable potential to bioaccumulate and biomagnify. This conclusion has been confirmed by the environmental toxicity effects in various organisms. It is also readily transported over long distances in the atmosphere, so that wet deposition is one of the major steps in the mercury cycle.
Prohibited areas:
To minimize exposure to mercury, several measures have been proposed. For example, electrical equipment (especially using reduced mercury), minimizing the standard value of mercury content in lamps or switches or using alternative substances. An estimated 11% of the total anthropogenic mercury emissions to the atmosphere in Europe in the mid-1990s were contributed by lighting and electrical equipment. Improving the energy efficiency of mercury-containing lamps can reduce mercury emissions.
RoHS:
The directive regulates electrical and electronic equipment that must not contain mercury as of 2008.
Except for the following
Small fluorescent light bulbs whose mercury content of heavy metals shall not exceed 5 mg per bulb
Straight fluorescent light bulbs whose mercury content of heavy metals shall not exceed 10 mg per bulb
Heavy metal mercury in laboratory equipment
Heavy metals lead, cadmium and mercury used in atomic absorption spectrometers. Hollow cathode tube and other heavy metal measurement equipment
TCO'01- Mobile Phones:
Mobile phones should not contain more than 2ppm of mercury
IV. Uses of Hexavalent Chromium in Electronic Products:
Hexavalent chromium is often used as chromic acid in the electrochemical industry. It is also used as coloring agent in pigment (also known as lead chromate) and cooling water circulation system, such as heat-absorbing pumps, industrial freezers and refrigerator heat exchangers in the anti-corrosion agent (sodium dichromate).
Hazards of hexavalent chromium:
Hexavalent chromium is an ingested toxicant/inhalation extremely toxicant, skin contact may cause sensitization; more likely to cause hereditary genetic defects, inhalation may be carcinogenic, and persistent danger to the environment. However, these are properties of hexavalent chromium; chromium metal, trivalent or tetravalent chromium do not have these toxicities.
Banned range:
In the European Union, hexavalent chromium, which causes cancer or mutations, is not allowed to be sold publicly. However, chromic acid is reduced to CrO (zero-valent) in the electrochemical industry and to CrO2 in the magnetic tape industry, so it does not affect the electrochemical industry or the magnetic tape industry.
RoHS:
Motor electronic equipment regulated by this directive must not contain hexavalent chromium since 2008.
Except for the following
Absorption freezer cooling systems using hexavalent chromium corrosion protection
TCO'01- Mobile Phones:
There is currently no regulatory specification for hexavalent chromium.
V. The use of brominated flame retardants in electronic products:
Added to electrical appliances and electronic plastics as flame retardants. The commonly used ones are decabromodiphenyl ether DBDE, octabromodiphenyl ether OBDE.
Hazards of Brominated Flame Retardants:
When discarded plastics of electrical and electronic items are subjected to uncontrolled thermal processes (i.e., temperatures below 12,000 degrees Celsius), brominated diphenyl dioctyl ether or fumarole (PBDD/F) may be formed. Both are carcinogenic and teratogenic. These substances may cause serious and widespread air pollution.
Range of Prohibition:
No further risk reduction measures are required for atmospheric ecosystems as long as the waste plastics are incinerated at the required temperatures. For aquatic, sediment and soil ecosystems, additional eco-toxicity studies are required to confirm potential risks. With regard to chemical accumulation through the food chain and potential effects on species higher up the food chain, it was concluded that "no further risk reduction measures are required for the use and disposal of DBDE and OBDE under normal conditions". Another study reported by WHO (1994) found "no measurable accumulation of DeBDE in meat and skin". A proposal to restrict the use of PBDEs (including DBDEs) was withdrawn by the European Executive Committee in 1993 in view of the European Parliament's concerns about fire safety and a reassessment of environmental risks. The EU risk assessment was as described above. However, the latest Waste Electrical and Electronic Equipment (WEEE) Directive proposes to restrict the use of these substances in a separate directive (RoHS). Sweden also intends to ban PBDE and DBDE.
RoHS:
Electrical and electronic equipment regulated by this directive must not contain brominated flame retardants as of 2008.
TCO'01- Mobile Phones: