UW Electrical & Computer Engineering



Toxins in WEEE (E-waste)

Most electrical and electronic devices today are made with a variety of metals and chemicals. When WEEE goes to the landfill – either domestically or abroad – the toxic chemicals that are inside of most of our electronics leach out into the environment, poisoning water and affecting animals, plants, and people. Click below to learn more about the impacts of these toxins that contaminate people and the environment once electronics reach the end of their useful life.


Lead  |  PBDEs  |  Dioxins and Furans  |  Cadmium  |  Arsenic  |  Mercury  |  Chromium


Lead in Electronics

Almost all electronic devices contain lead, with old cathode ray tube (CRT) monitors and televisions weighing in at an average 4-5 lbs of lead each, and with smaller devices containing traces of lead from soldering. Collectively, some 58,000 tons of lead emissions are released from e-waste recycling every year. The ever-evolving nature of electronics could mean less lead in future devices: the replacement of CRT monitors with liquid crystal (LCD) displays will reduce concentration of lead in e-waste, but may mean increasing mercury which is found in LCD displays and devices. A global movement for lead-free solder would also mean less lead in the waste stream of future generations.


When electronic waste goes to a responsible recycler, lead contained in parts and glass combined with lead can be removed safely so that lead does not enter the municipal waste stream. Lead components and lead-infused glass from CRT TVs and monitors can then be sold to a lead smelter so that it can be made into new products.  In more informal or unregulated recycling facilities, however, lead dust from dismantling of CRT glass, batteries, solder, and older PCBs is often inhaled by workers and lead from the remains of recycling processes and parts can enter into soil and water through a variety of pathways.


Lead in People and the Environment

Lead that is released into the air – which can occur when electronics are burned in municipal waste facilities or in backyard recycling centers – can travel long distances before settling to the ground, where it has a tendency to stick to soil particles. Lead can also move from soil into groundwater. Lead concentrations in the air in Guiyu, China were 3.1-4.6 times the concentrations of lead in some metropolitan cities like Seoul and Tokyo. Lead dust concentrations from dismantling WEEE in Guiyu and New Delhi were higher by factors of 207 to 220 when compared with US environmental standards for industrial soil lead levels.


Exposure to lead can occur through air, dust, water, and soil. Exposure to lead can affect almost every organ and system in the human body, damaging the nervous system, causing weakness in extremities, and increases in blood pressure or anemia. At higher levels, lead can cause brain and kidney damage, miscarriages in pregnant women, lower sperm production in men, and can ultimately cause death. Children are more vulnerable to lead poisoning than adults, and persistent exposure can lead to smaller babies and decreased mental capacities. Long-term exposure to lead dust can lead to anemia, kidney damage, high blood pressure, nerve and brain damage, miscarriage, and birth defects.


Children working on dismantling e-waste in China were shown to have higher blood lead levels than children living in other parts of China. In countries where large numbers of children work in disassembling and burning electronic waste, high health risks and learning difficulties can make getting out of poverty more difficult. Eighty percent of children in Guiyu suffer from respiratory diseases and are particularly vulnerable to lead poisoning. Blood lead levels in children in Guiyu exceeded the Chinese mean, meaning that poisoning is a serious threat to children’s health, most likely through air pollution.


Lead can also affect wildlife and plant life, and has been observed to cause muscle degeneration and weakness in birds, and disruption of physiological and biochemical processes in plants.


Polybrominated Diphenyl Ethers (PBDEs)

PBDEs in Electronics

Most plastics used in electronics such as TVs and large appliances contain a variety of flame retardant chemicals, collectively known as PBDEs. These chemicals prevent devices from over-heating, and are found in laptops and computers as well. Their use is banned in many countries around the world; EU regulations such as the RoHS (Restriction of the Use of Hazardous Substances) and the WEEE Directive ban the use of PBDEs, however, they have been used in products manufactured in other countries up until the late 2000s. Electronics before 2000 are likely to have higher levels of PBDEs than more current electronics. Most PBDEs in a device are released during the dismantling process, with emissions also produced from crushing and sorting of plastics in the recycling process. PBDEs lack chemical bonds between them and the plastics they are applied to, so they are more likely to leach from surfaces during recycling.


PBDEs in People and the Environment

PBDEs enter the environment during the use of electronic products, but are most commonly released during both formal and informal recycling. PBDEs can be released into the air, water, and soil. Burning of plastics and dismantling and shredding of electronics lead to release of PBDEs into the environment. Most common methods of exposure are inhalation, but people can also become exposed through touching contaminated soils. Studies show that children and infants have higher exposure to PBDEs than adults.


PBDEs in high levels have been measured in the atmosphere, sediment, water and soil, and also within the bodies of workers surrounding Chinese e-waste dismantling sites. High exposure can lead to abnormal changes in thyroid hormones and the functioning of the kidneys. Residents in Guiyu receive intake levels far exceeding the WHO tolerable daily limit, and children and child-bearing women are particularly vulnerable. Exposure can cause thyroid disruption and impaired memory and cognitive functions.


PBDEs do not dissolve easily in water, but stick to particles and settle to the bottom of rivers and lakes. They are also known to bioaccumulate in fish, meat, and dairy products. PBDEs build up in organisms and food chains were they have endocrine disrupting properties.


Dioxins and Furans (PCDDs and PCDFs)

PCDDs and PCDFs in Electronics

Dioxins and furan are released during open burning of wires and plastics, as well as during acid leaching, shredding, and other dismantling processes. Many forms of both dioxins and furans are banned in the United States. These chemicals enter the environment during manufacturing and use of electronics as well. Both formal and informal recycling processes that burn e-waste lead to PCDD and PCDF emissions.


PCDDs and PCDFs in People and the Environment

PCDDs and PCDFs can enter into the environment through air, dust, soil, and food. They do not break down in the environment and remain for long periods of time. These toxins travel long distances in the air and bind strongly to soils. They can be taken up by fish and can bioaccumulate in a food chain. They are identified as probable carcinogens.


Daily dioxin intake doses of children in Guiyu can be up to 2 times that of adults in the same area: exposure can affect cognition in children.



Cadmium in Electronics

The greatest consumption of refined cadmium is for the production of nickel-cadmium batteries, which accounted for 81% of total refined cadmium globally in 2004. Burning or dismantling of cadmium products such as batteries, PCBs, CRT glass, toners, plastics, and infrared detectors can lead to cadmium dust or ash in the air. Some 36,000 tons of cadmium are emitted during e-waste processing yearly. Cadmium from recycled electronic batteries can be recycled into new batteries.


Cadmium in People and the Environment

Cadmium enters soil, water, and air, and does not break down in the environment. Particles in the air can travel long distances, and cadmium binds strongly to soil particles. Cadmium products that end up in landfills lead to acid leachate that can seep into groundwater. Fish, plants, and animals can take up cadmium from the environment. Breathing high levels of cadmium can severely damage lungs. Eating food or drinking water with high levels can irritate the stomach and lead to vomiting and diarrhea. Long-term exposure to lower levels can lead to buildup in the kidneys and lead to kidney disease. Lung damage and fragile bones are other long-term effects. Cadmium has also been associated with deficits in cognition, learning and neuromotor skills in children. Cadmium is a known human carcinogen, and is in most cases toxic to plants as well.



Arsenic in Electronics

Arsenic can be found in circuit boards, semiconductors, LCD displays, computer chips, and more; and when these items are sent to landfills, arsenic can leach into the soil and the ground water. When arsenic is burned – either in incinerators or in informal recycling centers – arsenic can enter the atmosphere. Workers close to recycling plants in informal recycling areas can also be exposed to arsenic.


Arsenic in People and the Environment

Some evidence has shown that long-term exposure to arsenic in children results in lower IQs, and that exposure to arsenic in the womb and early childhood can lead to increased mortality as young adults. Exposure for both adults and children can lead to lung cancers and other nervous disorders. Arsenic in some plants and animals can lead to rapid growth in low doses, but in high doses can result in death. Arsenic in the ground water can lead to disrupting the natural pH of nearby waters, affecting humans and aquatic life that interact with these poisoned waters.



Mercury in Electronics

Mercury can be found in fluorescent tubes, switches in thermostats, older computers, batteries, and more. When electronic waste containing mercury is sent to landfill sites or is burned in incinerators or open burning, mercury is released into the environment. 13.6 tons of mercury are released as emissions during e-waste recycling every year.


Currently, mostly in developed countries, mercury in new electronics is being phased out thanks to increased awareness of its toxicity. This means, however, that electronics that are reaching their end-of-life still contain mercury, and some electrical and electronic equipment that has no substitute for mercury, such as fluorescent lamps, will lead to an increase of mercury in obsolete electronics for the near future. Mercury used in electronics annually accounts for approximately 22 percent of all the world’s mercury consumption. To safely recycle bulbs, recyclers in formally regulated facilities use airtight machines to avoid releasing mercury vapor to crush and separate the glass, aluminum, and the mercury from fluorescent bulbs. Once enough mercury has been collected, it is shipped to a mercury refiner who will resell it.


Mercury in People and the Environment

Mercury is primarily absorbed into the human body by breathing airborne vapors, and it is these vapors that make not only waste electrical and electronic equipment dangerous for those who deal with it, but also workers who produce it. Workers at a fluorescent lamp manufacturing plant were shown to have higher concentrations of mercury in their bodies, which lead to health problems such as losing color discrimination. Other research has shown that mercury exposure can lead to long-term damage to information processing, and psychomotor functioning, as well as increased depression and anxiety. Children have been shown to be particularly sensitive to mercury vapors, and newborns and infants can be at greater risk if they live near informal recycling industries Long-term exposure can lead to nerve and brain damage and birth defects.


Mercury can also cause environmental problems, as it is known to biomagnify in aquatic foodwebs. Mercury uptake by fish can lead to a range of blood and behavioral abnormalities and can cause death.



Chromium in Electronics

Chromium can be found in data tapes, floppy discs, and is used for coating and plating in many electronics to prevent rust. 198,000 tons of Chromium are produced as emissions from global processing of e-waste annually. Two different types of Chromium are used in electronics; Chromium(III) and Chromium (VI) are used in chrome plating, and Chromium(VI) is used as coating to prevent corrosion.


Chromium in People and the Environment

Chromium(III) is an essential element, helping the body use macronutrients. However, excessive intake can still lead to damage in the body. Chromium(VI) compounds are well-established environmental contaminants and are human respiratory carcinogens. High levels of Chromium exposure can lead to impaired motor function and irritation to linings of the nose and stomach, and some lab tests on animals suggest it can damage the male reproductive system and sperm. High levels of Chromium have been found in areas with large informal e-waste recycling in Guiyu, China where it was tested and found in soil, rivers, ground water, and in people.


Chromium enters the environment during the manufacturing, use, and disposal of electronic devices, and can contaminate air, soil, and water. Chromium does not remain in the atmosphere long, eventually depositing into soil and water. It is not readily bioaccumulated like other toxins.


ATSDR (2011). ToxFAQs for Cadmium. Retreived from http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=47&tid=15
ATSDR (2015). ToxFAQs for Chromium. Retrieved from http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=17
ATSDR (2015). ToxFAQs for PBDEs. Retrieved from http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=1462&tid=183
ATSDR (2014). ToxFAQs for PCBs. Retrieved from http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=140&tid=26
California Department of Public Health (2012). Electronic Waste Recycling: Working Safely. Hazard Evaluation System and Information Service Fact Sheet: Richmond, CA.
Chen, A., Dietrich, K.N., Huo, X., Ho, S. (2011). Developmental Neurotixicants in E-Waste: An Emerging Health Concern. Environmental Health Perspectives, 119 (4).
Honda, S., Li, J. (2008). Mercury in e-waste: Environmentally unsound disposal. Tech Monitor, Jul-Aug, 16-22.
Huo, X., Peng, L., Xu, X. Zheng, L., Qiu, B., Qi, Z., Zhang, B., Han, D., Piao, Z. (2007). Elevated blood lead levels of children in Guiyu, an electronic waste recycling town in China. Environmental Health Perspectives, 115(7), 1113-1117.
Feitosa-Santana, C., Costa, M., Lago, M., Ventura, D. (2007). Long-term Loss of Color Vision after Exposure to Mercury Vapor. Brazilian Jounral of Medical and Biological Research, 40, 409-414.
Park, J.-E., Kang, Y.-Y., Kim, W.-I., Jeon, T.-W., Shin, S.-K.,Jeong, M.-J., Kim, J.-G. (2014). Emission of polybrominated diphenyl ethers (PBDEs) in use of electric/electronic equipment and recycling of e-waste in Korea. Science of the Total Environment, 1414-1421.
Robinson, B.H. (2009). E-waste: An assessment of global production and environmental impacts. Science of the Total Environment 408, 183-191.
Sepúlveda, A., Schulep, M., Renaud, F.G., Streicher, M., Kuehr, R., Hagelüken, C., & Gerecke, A.C. (2010). A review of the environmental fate and effects of hazardous substances released from electrical and electronic equipments during recycling: Examples from China and India. Environmental Impact Assessment Review, 30, 28-41.
Silicon Valley Toxics Coalition (2002). Just say no to E-waste: Background Document on Hazards and Waste from Computers. http://svtc.igc.org/cleancc/ pubs/sayno.htm.
Straskraba, V., Moran, R. (1990). Environmental occurrence and impacts of arsenic at gold mining sites in the western United States. International Journal of Mine Water, 9(1-4), 181-191.
Tue, N.M., Takahashi, S., Subramanian, A., Sakai, S., Tanabe, S. (2013). Environmental contamination and human exposure to dioxin-related compounds in e-waste recycling sites of developing countries. Environmental Sciences: Processes and Impacts, 15, 1326-1331.
UNEP (2011). Study on the possible effects on human health and the environment in Asia and the Pacific of the trade of products containing lead, cadmium and mercury. United Nations Environment Programme – Chemical Branch.
United States Geological Survey (2015). Arsenic. Mineral Commodity Summaries. http://minerals.usgs.gov/minerals/pubs/commodity/arsenic/mcs-2015-arsen.pdf
Xu, X., Yekeen, T.A., Liu, J., Zhuang, B., Li, W., Huo, X. (2015) Chromium exposure among children from an electronic waste recycling town of China. Environmental Science and Pollution Research, 22, 1778-1785.
Zachi, E., Ventura, D., Faria, M. Taub, A. (2007). Neuropsychological Dysfunction related to Earlier Occupational Exposure to Mercury Vapor. Brazilian Journal of Medical and Biological Research.

© 2015 Denise Wilson and Rachel Roberts