The composition of e-waste is complex, more than half of the materials are harmful to human body, some are even highly toxic. For example, a computer has more than 700 components, half of which contain mercury, arsenic, chromium and other toxic chemicals; televisions, refrigerators, cell phones and other electronic products also contain lead, chromium, mercury and other heavy metals; laser printers and photocopiers contain toner and so on.
When e-waste is landfilled or incinerated, the heavy metals in it penetrate into the soil and enter rivers and groundwater, which will cause pollution of local soil and groundwater, and directly or indirectly cause damages to the local residents and other organisms; and the organic matter is incinerated, which releases a large amount of hazardous gases, such as highly poisonous dioxins, furans, PCBs and other carcinogens, which cause harm to the natural environment and human body. Harmful to the natural environment and human body. Lead destroys human nerves, blood system and kidneys, and affects the development of young children's brains. Chromium compounds (especially hexavalent chromium) can damage human DNA and cause asthma and other diseases.
Circuit boards seem to be more valuable, and the most work goes into them. Workers usually start by gathering up usable components for resale, then plunge integrated circuit chips into aqua regia to dissolve the gold inside; used boards are also put into acid solutions to extract nonferrous metals such as copper. The last remaining waste is useless fiberglass substrates, which are then incinerated to release highly toxic substances such as dioxin.
Batteries, switches, sensors, and cell phones can contain mercury, and in the presence of microorganisms, inorganic mercury is transformed into methylmercury, which enters the human body through enrichment in the food chain, and can severely damage the nervous system and cause death in severe cases. Freon from abandoned air-conditioning and refrigeration equipment will destroy the ozone layer when emitted into the atmosphere, causing the greenhouse effect and increasing the incidence of skin cancer. Brominated flame retardants and chlorine-containing plastics emit toxic substances when landfilled at low levels or improperly burned and recycled.
Hazardous substances in e-waste
E-waste contains a very large number of toxic substances, such as lead and cadmium in circuit boards; lead oxide and cadmium in cathode ray tubes in monitors; mercury in flat panel displays; cadmium in computer batteries; polychlorinated brominated ethylenethanes (PCBs) in capacitors and converters; brominated flame retardants in circuit boards; and when burned wires to take the copper will release highly toxic substances dioxins and furans. dioxins and furans. Because of the hazardous nature of e-waste, handling and recycling them involves stringent legal and environmental requirements. There are serious pollution problems when computer waste is disposed of in landfills or incinerated, with landfills leaking toxins into groundwater and incineration producing gaseous toxins including dioxins. However, the recycling of computers can also involve health and environmental issues, especially when the recycling industry prioritizes profits over measures to protect the environment and worker health. Lead - The harmful effects of lead have long been recognized, and it was banned from gasoline in some countries as early as the 1970s. Lead can damage the central nervous system, blood system, kidneys, and reproductive system, and can have a negative impact on children's brain development. Lead can accumulate in the environment, which can have a strong and long-lasting effect on plants, animals, and microorganisms. The main lead-containing parts of computers are: the glass screens of computer monitors (1.4~3.5 kg/per monitor), and the solder of circuit boards or other components. Cadmium - Cadmium compounds are also very harmful to people and can accumulate in the body, especially in the kidneys. Cadmium is contained in the following components, SMD resistors, infrared generators, semiconductors, etc. Cadmium is also a curing agent for plastics and is found in old cathode ray tubes. Mercury - Mercury can cause damage to many organs, including the brain, kidneys, ovaries, and worse, fetal development can be quite sensitive to mercury passed from the mother. We know that when inorganic mercury is spilled into water, it is converted to methylmercury and sinks to the bottom. Methylmercury can easily accumulate in the body, as well as being enriched through the food chain, especially in fish. It is estimated that 22% of the world's annual mercury consumption is in electrical and electronic products, which are used in thermometers, sensors, dampers, transducers (e.g., in circuit boards and measuring devices), medical devices, lamps, cell phones, and batteries. Mercury is also used in flat screen monitors, gradually replacing the original cathode ray tube monitors. Hexavalent Chromium - Hexavalent chromium is still used in steel sheets for rust prevention as well as hardening and beautifying. It readily passes through cell membranes and is then absorbed, which can have a toxic effect on contaminated cells. Hexavalent chromium also damages DNA and is an extremely toxic substance in the environment. Plastics containing PVC - there is an average of 13.8 pounds of plastic per computer. A large amount of the plastic used in electronics (26%) is PVC-containing. PVC is mainly used for wrapping wiring and computer casings, although many computer molds have begun to be made from non-toxic ABS. PVC is widely used mainly because of its fire-resistant properties, and like many other chlorine-containing compounds, PVC produces dioxin when it burns at certain temperatures. Brominated Flame Retardants (BFRs) - BFRs are used in the plastic casings of electronic products and in circuit boards to prevent fuming, and some types of BFRs have been targeted for elimination by the European Parliament between 2003 and 2006. Barium - Barium is a soft, silvery-white metal used in computer monitor cathode ray tube screens to protect users from radiation, and studies have shown that even short-term exposure to barium can cause brain swelling, muscle weakness, and damage to the heart, liver, and spleen. However, there is no information on the effects of long-term exposure to barium on people. Studies in animals have shown increased blood pressure and changes in the heart after feeding barium for a period of time. Beryllium - Beryllium is a steel-gray metal that is fairly light, hard, a good conductor of electricity and heat, and non-magnetic, properties that make beryllium well suited for a variety of industrial uses, including, for example, electronics like computers. In computers, beryllium is widely used in motherboards and keyboard backplanes (an alloy of beryllium and copper is used to strengthen the elasticity of the connectors while maintaining electrical conductivity). Beryllium is considered a carcinogen that causes lung cancer. The main concern is ash and mist from beryllium friction. Workers exposed to beryllium for long periods of time, even in small doses, are susceptible to "beryllium chronic disease," a lung disease. Exposure to beryllium can also cause a skin condition characterized by minor abrasions and swelling, and studies have shown that beryllium chronic disease persists even after years of non-exposure to beryllium. Ink - Computer peripherals such as printers contain black or colored ink. The main component of black ink is carbon black. Breathing is the primary route of exposure, and intense exposure can lead to irritation of the respiratory system. The International Agency for Research on Cancer has classified carbon black as a Group 2B carcinogen, which is potentially carcinogenic to humans. There has been little research on colored inks, and some reports indicate that these colored inks (blue, yellow and red) contain heavy metals. Phosphides and other additives - Phosphides are inorganic compounds that are used to coat the inner surface of cathode ray (CRTs) glass. The phosphide effect is what we can see in the display image.The harmful nature of phosphorus in CRTs is not well known, but here's what the U.S. Navy says in their guidance regulations, "Don't touch the phosphorus coating of CRTs: it's highly toxic. If you break CRTs, carefully clean up the glass shards. If you touch the phosphorus coating. Get it taken care of by a doctor." Phosphorus cladding also contains heavy metals such as zinc and vanadium as additives. These metals and their compounds are also toxic. These can be hazardous to workers who disassemble CRTs by hand.