UW Electrical & Computer Engineering

Impact of WEEE

Impacts of WEEE (e-waste)

Despite making up only 2% of the trash in landfills, e-waste accounts for nearly 70% of the toxic heavy metals in these landfills. The consequences of improper disposal of e-waste, both in landfills and other, non-designated dumping sites, are extremely serious, ranging from creating public health problems to polluting ecosystems for generations to come.   Click below to learn more about how e-waste can hurt both human and ecosystem health.

Air  |  Soil  |  Water


How does e-waste contaminate air?

Air can be contaminated by e-waste primarily when e-waste is transported to countries where recycling processes are poorly regulated, as is typical in informal economies.   In these informal economies, e-waste is often dismantled and shredded, releasing dust or large particulates into the immediate environment where the respiratory health of workers without proper respiratory protection is hurt, often seriously and chronically.   E-waste of little value is often burned and low value e-waste tends to contain a great deal of plastic. Unregulated or under-regulated burning is often carried out at lower temperatures and releases toxins, such as dioxins, which are potent and damaging to human and animal health in a myriad of ways.   Burning also releases fine particles which can travel hundreds if not thousands of miles and bring about negative consequences to respiratory health and bypass the body’s defense mechanisms, increasing the risk for a wide range of chronic diseases and cancers.  Finally, higher value materials, such as gold and silver, are often extracted from highly integrated electronics and e-waste using acids, desoldering, and other chemicals and techniques which release additional damaging fumes into local communities when recycling is not properly regulated.   The impacts of informal recycling of e-waste on air are worst for the workers who handle this waste, but can extend, tens, hundreds, and sometimes thousands of miles away from recycling sites.

How are ecosystems impacted?

Some animal species are more profoundly impacted by air pollution than others, which in addition to endangering these species, also endangers the biodiversity of regions that are chronically and heavily polluted.   Over the long term, air pollution can hurt water quality, soil chemistry, and plant species, creating damaging and irreversible changes in ecosystems.   For example, lead levels in air near informal recycling hubs like Guiyu, China can be up to three times those found in industrial European sites.   Lead can be inhaled while still in the air and ingested when it returns to water and soil.  Once ingested or inhaled, it can bio-accumulate up the food chain, causing disproportionate neurological damage to larger animals and wildlife, including human beings.

How are human beings impacted?

Human beings can inhale fine (small) particles generated from informal recycling practices and toxic chemicals from these same practices.  Fine particles are of particular concern because (a) they can travel long distances through air from their point of origin, thus impacting communities far away from where the pollution was generated; and (b) they bypass the body’s respiratory defense mechanisms and can cause a wide range of health problems, chronic, acute, and otherwise. Short term exposure to fine particles is often linked with eye irritation, asthma attacks, and acute bronchitis while long term exposure can result in reduced lung function, chronic bronchitis, lung cancer, and a wide range of systemic problems that extend well behind compromised respiratory health. These risks are especially heightened for older adults who already have heart or lung issues such as asthma or coronary heart disease. Being exposed to particle pollution can aggravate these diseases and even lead to death. For children, inhaling particles can not only result in immediate respiratory difficulty but can also increase the risk of debilitating respiratory disease later in life.


Despite the fact that lead-free solder is becoming more popular in electronics, desoldering of e-waste to dismantle components on printed circuit boards is a process that still often releases fumes containing lead into the air.  Acute exposures by inhalation can result in lead poisoning. Children are especially vulnerable to this as toxicity of lead can have chronic and negative effects on brain development and nervous system, leading to lifelong lower IQ, developmental delays, and behavioral disorders.  In adults, the short term effects of acute lead poisoning include severe headaches, abdominal pain and memory loss. Long term exposure to lead can damage the reproductive system, the kidneys, increase blood pressure, cause miscarriages, stimulate anemia, and damage sperm.


Finally, the chemical processes used to leach or extract precious metals from e-waste often involve acids, which when heated to carry out the intended extraction processes, can release toxic fumes.  One such example is the extraction of gold. In today’s world, two methods are used for this procedure. The first one is a dangerous process called hydro-metallurgy, which uses leaching chemicals such as cyanide and a mixture of nitric acid and hydrochloric acid to release and collect precious metals from electronics. While hydro-metallurgy is dangerous, it does not affect air quality nearly as much as pyro-metallurgy.  Pyro-metallurgy, as the name suggests, heats electronics to very high temperatures to release gold and other precious metals from electronics. This process releases very dangerous furans and dioxins into the air. Inhaling these toxins are very hazardous as they can cause skin disorders (such as chloracne), liver problems, heart disease, and impairment of the immune, endocrine and reproductive systems. Specifically, dioxins are linked with several forms of cancer.  Since they are fat soluble and hydrophobic, they accumulate and remain in the body for a lifetime.


How does e-waste contaminate soil?

Soil can be contaminated in two primary ways from e-waste:  (a) through direct contact with contaminants from e-waste or the byproducts of e-waste recycling and disposal; or (b) indirectly through irrigation from contaminated water.


When e-waste is improperly disposed in regular landfills or illegally dumped, both heavy metals (lead, arsenic, cadmium, and others) and flame retardants in e-waste can leach directly from the e-waste into the soil, causing contamination of underlying groundwater or contaminating crops that may be planted in that soil now or in the future.


When e-waste is not recycled properly as is the case in areas of the world where recycling practices for e-waste are not regulated or are informally monitored, soil can become directly contaminated by (a) effluent or waste products from leaching practices which extract precious metals and other valuable materials from e-waste; (b) coarse particles and bottom ash generated from dismantling, shredding, or burning of e-waste; and (c) leaching of heavy metals not recovered during recycling into underlying soil during disposal.   Practices used to extract precious metals from e-waste such as mercury amalgamation or cyanide leaching can release additional toxic substances to the soil.  Dismantling can also release large, coarse particles into the air, which due to their size and weight, quickly re-deposit to the ground and subsequently contaminate soil. Shredding or burning of e-waste produces ash which can be heavily contaminated by both heavy metals and flame retardants (polybrominated diphenyl ethers or PBDEs) that leach into underlying soil.  By similar processes, heavy metals left over from incomplete recycling can also contaminate underlying soil.  How and how much soil is contaminated depends on a wide range of factors including temperature, pH, soil type, climate, and soil composition. Much of this soil contamination is persistent and these pollutants remain in the soil for a long time, some evolving into even more toxic species than in their original form.  Soil is also indirectly impacted by e-waste recycling through contact with contaminated water; further information about how water can be impacted by e-waste is here

How are ecosystems impacted?

Fundamentally, heavy metals (from improper e-waste disposal and incomplete recycling activities), PBDEs (from burning , shredding, and dismantling), dioxins/furans (from incomplete burning) and acidification from recycling practices which involve leaching change the composition of soil in unpredictable and complex ways.   These changes can be very harmful to micro-organisms in the soil and plants, as well as animals and wildlife that rely on these plants for survival.  Plants often suffer from damaged cell structure, altered metabolism, and reduced growth in contaminated soils.  In addition, some plant species can be doubly impacted by e-waste through the contamination of underlying soil and through direct contact with contaminants.  Lead, for example, can coat the surface of leaves, reducing the rate of photosynthesis within a plant and causing damage or death.


Exposure to contaminated plants/vegetation can create compounding exposures to heavy metals (e.g. lead, arsenic, cadmium), dioxins, furans, PBDEs and other potent pollutants.  Animals are not only inhaling contaminated air but also consuming plants contaminated by underlying soil. Since many of these pollutants bio-accumulate up the food chain, the larger the animal, the more the impact, which can cause complex and disturbing disruptions to biodiversity and ecosystem balance in contaminated areas.

How are human beings impacted?

Humans are doubly impacted by contaminated soil via consuming crops grown in contaminated soil and eating eggs, meat, and fish where toxic substances have bio-accumulated (increased in concentration) up the food chain.  For children, these effects are further compounded because children are more likely to play in contaminated soil and ingest contaminated soil through poor hygiene or inadequate hand-washing practices.


For example, polybrominated diphenyl ethers (PBDEs) which are used as flame retardants in plastics for a wide range of electronic devices and appliances are a byproduct of dismantling and shredding as well as the burning of e-waste.   While PBDE concentrations in soils affected by dust from dismantling e-waste are minimal, concentrations in soils near informal recycling sites and shredding practices in India and China jump to as much as 445 times those found in the urban soils of developed countries.   PBDE in rice crops grown in contaminated soils can be many times higher than rice grown in soils near urban areas that do not host informal e-waste recycling.   PBDEs are endocrine disruptors that affect oestrogen and thyroid hormones and prevent nervous and reproductive systems from developing properly.


Like air and water, soils also become contaminated by heavy metals from incomplete recycling and improper disposal of e-waste.  Cadmium, arsenic, and lead all cause neurological damage and delays in development among children and increase risk of multiple chronic diseases and cancers in adulthood.  Mercury, generated from both e-waste itself and the processes involved in recycling this waste, not only hurts kidneys, lungs, and skin but like other heavy metals, has compounding or synergistic interactions with other metals that are so complex that they are only beginning to be understood in the research community.


How does e-waste contaminate water?

Water can be contaminated by e-waste in two major ways:  (a) via landfills that are not properly designed to contain e-waste; and (b) via improper recycling and subsequent disposal of e-waste.   Electronic components often contain precious metals and other desirable materials that make e-waste lucrative for many to recycle and reuse these materials, particularly certain impoverished communities in developing countries.   Extracting materials from highly integrated systems, as many electronics are in modern design, is complicated and can require shredding, burning, leaching, and other processing that produces toxic byproducts in air, water, and soil.   Surface water, in particular, is affected by the chemical processes used to extract precious metals like gold from electronic devices.  These processes typically leach or strip precious materials away from less valuable materials like plastic using acids and other toxic chemicals that, when improperly treated or regulated, are released into local water sources such as streams, ponds, and rivers.   Through these pathways, acidification and toxification of water can extend to communities miles away from a recycling site, impacting public and ecosystem health in many, many ways.   Ground water can also be impacted by improper disposal or dumping of e-waste as heavy metals (like lead, arsenic, and cadmium) and other persistent chemicals leach from landfills and illegal dump sites into ground water tables, affecting people and animal life for many miles around.

How are ecosystems impacted?

One of the biggest impacts to ecosystems through water sources contaminated by e-waste is through acidification of surface waterways.  Acids used to extract and leach precious metals from e-waste during recycling and reuse enter into local waters when improperly handled.   Acidification can kill marine and freshwater organisms, disrupt biodiversity, enable some species to dominate over others, and disrupt ecosystems at a level that extends far from communities that are involved in processing e-waste.   An example of extreme acidification is evident in Guiyu, China where industrial waste and improper disposal of electronic parts has left local streams black and polluted. The water supplies are extremely acidic, so much so that surface waters could disintegrate a penny within a few hours. If allowed to persist, acidification conditions can damage ecosystems to the point that recovery is unlikely or even impossible.


Heavy metals can also enter surface waters through improper recycling and handling of e-waste.  For example, in fish, ingestion of mercury readily leads to neurological damage, permanent disabilities and damage to the immune system. Heavy metals can also lead to tissue and gill damage as well as erratic movements among many species of fish.  These heavy metal impacts extend well beyond fish, above and beneath these fish on the food chain, ultimately extending to human beings and public health.

How are human beings impacted?

When surface waters are contaminated by the products of e-waste, those drinking from, bathing, and recreating in these waters are impacted.  Many toxic chemicals can impact surface waters but heavy metals can impact both surface and ground waters.   In extreme cases, e-waste can leave groundwater undrinkable. In some recycling venues such as in Mandoli, India, water samples showed amounts of mercury that were almost 710 times the limit recommended by the Indian government and lead at almost 11 times the recommended exposure limit. Bioaccumulation of heavy metals within organisms like fish lead to contamination up the food chain, all the way to humans and are the primary route of exposure for many people to heavy metals.  Heavy metals are also persistent in the environment and do not degrade upon exposure to sunlight or other environmental conditions.  As a result, they persist in both surface waters and can make their way down (leach) into groundwater tables, creating exposure risks to many both close to and many miles away from the original point of contamination.


If consumed, the heavy metals found in contaminated water can wreak havoc on the body. Toxins such as lead, mercury and cadmium (all found in printed circuit boards and other electronics) impact the nervous and reproductive systems as well as the organs. These impacts are particularly pronounced among children and the elderly and recent research increasingly points to compounding effects of exposure to multiple heavy metals.  No longer can exposure to heavy metals be considered one at a time.  Instead, it is the sum of heavy metals to which a person is exposed that determines the ultimately severity of the health impact.


The result of heavy metal exposure as a result of improper e-waste recycling is well documented. In Guiyu, China, often coined the e-waste recycling capital of the world, 169 children were tested for concentrations of lead within their blood. Over 82% showed much higher than average levels of lead, with the highest concentration being in children whose families worked directly with taking apart printed circuit boards and other electronics. Similar impacts are seen with other heavy metals and the long term neurological impacts, both in this and the next generation, are disturbing.

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© 2016 Denise Wilson