Waste Management 33 (2013) 1237–1250

Contents lists available at SciVerse ScienceDirect

Waste Management journal homepage: www.elsevier.com/locate/wasman

Review

Electronic waste management approaches: An overview
Peeranart Kiddee a,b, Ravi Naidu a,b,⇑, Ming H. Wong c a Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095, Australia
Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes Campus, Adelaide, SA 5095, Australia c Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, China b a r t i c l e

i n f o

Article history:
Received 27 July 2012
Accepted 8 January 2013
Available online 10 February 2013
Keywords:
Electronic waste
Life Cycle Assessment (LCA)
Material Flow Analysis (MFA)
Multi Criteria Analysis (MCA)
Extended Producer Responsibility (EPR)

a b s t r a c t
Electronic waste (e-waste) is one of the fastest-growing pollution problems worldwide given the presence if a variety of toxic substances which can contaminate the environment and threaten human health, if disposal protocols are not meticulously managed. This paper presents an overview of toxic substances present in e-waste, their potential environmental and human health impacts together with management strategies currently being used in certain countries. Several tools including Life Cycle Assessment (LCA),
Material Flow Analysis (MFA), Multi Criteria Analysis (MCA) and Extended Producer Responsibility (EPR) have been developed to manage e-wastes especially in developed countries. The key to success in terms of e-waste management is to develop eco-design devices, properly collect e-waste, recover and recycle material by safe methods, dispose of e-waste by suitable techniques, forbid the transfer of used electronic devices to developing countries, and raise awareness of the impact of e-waste. No single tool is adequate but together they can complement each other to solve this issue. A national scheme such as EPR is a good policy in solving the growing e-waste problems.
Crown Copyright Ó 2013 Published by Elsevier Ltd. All rights reserved.

1. Introduction
Managing electronic waste (or e-waste) is one of the most rapidly growing pollution problems worldwide. New technologies are rapidly superseding millions of analogue appliances leading to their disposal in prescribed landfills despite potentially their adverse impacts on the environment. The consistent advent of new designs, ‘‘smart’’ functions and technology during the last 20 years is causing the rapid obsolescence of many electronic items. The lifespan of many electronic goods has been substantially shortened due to advancements in electronics, attractive consumer designs and marketing and compatibility issues. For example, the average lifespan of a new computer has decreased from 4.5 years in 1992 to an estimated 2 years in 2005 and is further decreasing (Widmer et al., 2005) resulting in much greater volumes of computers for either disposal or export to developing countries. While difficult to quantify the volume of e-waste generated globally, Bushehri
(2010) presented an overview of the volume of e-waste generated in a range of categories in China, Japan and US based on available information for the period 1997–2010 (Table 1). This report estimates that over 130 million computers, monitors and televisions become obsolete annually and that the annual number is growing
⇑ Corresponding author. Address: CERAR – Centre for Environmental Risk
Assessment and Remediation, Building X, University of South Australia, Mawson
Lakes, SA 5095, Australia. Tel.: +61 8 8302 5041; fax: +61 8 8302 3124.
E-mail addresses: ravi.naidu@crccare.com, ravi.naidu@unisa.edu.au (R. Naidu).

in the United States (Bushehri, 2010). Around 500 million computers became obsolete between 1997 and 2007 in the United States alone and 610 million computers had been discarded in Japan by the end of December 2010. In China 5 million new computers and 10 million new televisions have been purchased every year since 2003 (Hicks et al., 2005), and around 1.11 million tonnes of e-waste is generated every year, mainly from electrical and electronic manufacturing and production processes, end-of-life of household appliances and information technology products, along with imports from other countries. It is reasonable to assume that a similar generation of e-waste occurs in other countries.
E-waste generation in some developing countries is not such a cause for concern at this stage because of the smaller number and longer half-life of electronic goods in those countries due to financial constraints, on both local community and national scales.
The major e-waste problem in developing countries arises from the importation of e-waste and electronic goods from developed countries because it is the older, less ecologically friendly equipment that is discarded from these Western countries 80% of all e-waste in developed countries is being exported (Hicks et al., 2005). Limited safeguards, legislation, policies and enforcement of the safe disposal of imported e-waste and electronic goods have led to serious human and environmental problems in these countries. For instance, e-waste disposal impacts on human health has become a serious issue that has already been noted in case studies from China (Chan et al., 2007; Huo et al., 2007; Qu et al., 2007; Wang et al.,
2009b; Xing et al., 2009; Zhao et al., 2008; Zheng et al., 2008).

0956-053X/$ - see front matter Crown Copyright Ó 2013 Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.wasman.2013.01.006 1238

P. Kiddee et al. / Waste Management 33 (2013) 1237–1250

Table 1
The quantity of e-waste annually generated in the United States of America, Japan and China.
Countries

Products

Quantity (million)

Classification

Years

References

United States
Japan
China

Computers
Computers
Computers
Televisions

500
610
5
10

E-waste
E-waste
New products
New products

1997–2007
2010
Every year
Since 2003

Bushehri (2010)
Bushehri (2010)
Hicks et al. (2005)

Concern arises not just from the large volume of e-waste imported into developing countries but also with the large range of toxic chemicals associated with this e-waste. Numerous researchers have demonstrated that toxic metals and polyhalogenated organics including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) can be released from e-waste, posing serious risks of harm to humans and the environment (Czuczwa and
Hites, 1984; Robinson, 2009; Williams et al., 2008). A review of published reports on e-waste problems in developing countries, and countries in transition, showed that China, Cambodia, India,
Indonesia, Pakistan, and Thailand, and African countries such as
Nigeria, receive e-waste from developed countries although specific e-waste problems differ considerably between countries. For instance, African countries mainly reuse disposed electronic products whereas Asian countries dismantle those often using unsafe procedures (US Government Accountability Office, 2008; Wong et al., 2007a). Social and human health problems have been recognised in some developing countries and it is worth noting that China, India, and some other Asian countries have recently amended their laws to address the management and disposal of e-waste imports (Widmer et al., 2005). Moreover, some manufacturers of electronic goods have attempted to safely dispose of e-waste with advanced technologies in both developed and developing countries
(US Government Accountability Office, 2008; Widmer et al., 2005).
Problems associated with e-waste have been challenged by authorities in a number of countries and steps were taken to alleviate them with the introduction of management tools and laws at the national and universal levels. Life Cycle Assessment (LCA), Material
Flow Analysis (MFA) and Multi Criteria Analysis (MCA) are tools to manage e-waste problems and Extended Producer Responsibility
(EPR) is the regulation for e-waste management at the national scale. This review provides an overview of the risk that e-wastes poses to human and environmental health from recycling and landfill disposals together with tools for the management of such wastes. Human toxicity of hazardous substances in e-waste is based on published case studies from e-waste recycling in China,
India and Ghana.

2. Human toxicity of hazardous substances in e-waste
E-waste consists of a large variety of materials (Zhang and
Forssberg, 1997), some of which contain a range of toxic substances that can contaminate the environment and threaten human health if not appropriately managed. E-waste disposal methods include landfill and incineration, both of which pose considerable contamination risks. Landfill leachates can potentially transport toxic substances into groundwater whilst combustion in an incinerator can emit toxic gases into the atmosphere. Recycling of e-waste can also distribute hazardous substances into the environment and may affect human health. While there are more than 1000 toxic substances (Puckett and Smith, 2002) associated with e-waste, the more commonly reported substances include: toxic metals (such as barium (Ba), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), lithium (Li), lanthanum (La), mercury (Hg), manganese

(Mn), molybdenum (Mo), nickel (Ni), silver (Ag), hexavalent chromium (Cr(VI)) and persistent organic pollutants (POPs) such as dioxin, brominated flame retardants (BFRs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polyvinyl chloride (PVC) (Table 2).
E-waste disposals impact human health in two ways which include: (a) food chain issues: contamination by toxic substances from disposal and primitive recycling processes that result in byproducts entering the food chain and thus transferring to humans; and (b) direct impact on workers who labour in primitive recycling areas from their occupational exposure to toxic substances. Along with this, numerous researchers have demonstrated a direct impact of backyard recycling on workers. The danger of e-waste toxicity to human health, both in terms of chronic and acute conditions, has become a serious societal problem and has been well demonstrated by case studies in China (Chan et al., 2007;
Huo et al., 2007; Qu et al., 2007; Wang et al., 2009b; Xing et al.,
2009; Zhao et al., 2008; Zheng et al., 2008), India (Eguchi et al.,
2012; Ha et al., 2009) and Ghana (Asante et al., 2012). For instance, blood, serum, hair, scalp hair, human milk and urine from people who lived in the areas where e-wastes are being recycled showed the presence of significant concentrations of toxic substances. Qu et al. (2007) studied PBDEs exposure of workers in e-waste recycling areas in China and found high levels of PBDEs with the highest concentration of BDE-209 at 3436 ng/g lipid weight in the serum of the sample groups. This is the highest concentration of
BDE-209 in humans so far recorded. High levels of Pb (Huo et al.,
2007; Zheng et al., 2008) and Cd (Zheng et al., 2008) were found in the blood of children around e-waste recycling regions. Zhao et al. (2008) detected PBBs, PBDEs and PCBs in hair samples at
57.77, 29.64 and 181.99 ng/g dry weight, respectively which were higher than those from reference sites. Wang et al. (2009b) found
Cu (39.8 lg/g) and Pb (49.5 lg/g) in scalp hair samples. PCDD/Fs
(Chan et al., 2007) and PCBs (Xing et al., 2009) were detected in human milk samples at 21.02 pg/g and 9.50 ng/g, respectively. In India concentrations of Cu, Sb and Bi in the hair of e-waste recycling workers was higher than at the reference site (Ha et al., 2009) and levels of tri to tetra-chlorinated PCBs, tri to tetra-chlorinated OHPCBs, PBDEs, octa-brominated OH-PBDEs, and tetra-BPhs in the serum of workers from e-waste recycling areas were higher than those in serum taken from people living near the coastal area (Eguchi et al., 2012). Moreover, in Ghana significant concentrations of
Fe, Sb and Pb in the urine of workers from primitive recycling sites were found at 130, 0.89 and 6.06 lg/l, respectively. These were higher than at reference sites (Asante et al., 2012). These findings confirm that human exposure to heavy metals and POPs released from e-waste treatment processes pose significant health risk to workers and local inhabitants especially women and children. Also these studies demonstrate the effect of long-term exposure to human. Similar studies need to be extended to other developing countries or countries in transition where back yard e-waste recycling is being conducted. Although, the Stockholm Convention
(UNEP, 2012) takes action to reduce and prevent global contamination from POPs, there has been significant delay with the implementation of guidance and legislation in some countries. For

P. Kiddee et al. / Waste Management 33 (2013) 1237–1250

1239

Table 2
Common toxic substances associated with e-waste and their health impacts. Sources: Five Winds International (2001), Puckett and Smith (2002), Ecroignard (2006) and Herat
(2008).
Substance

Applied in e-waste

Health impact

Antimony (Sb)

a melting agent in CRT glass, plastic computer housings and a solder alloy in cabling Gallium arsenide is used in light emitting diodes Sparkplugs, fluorescent lamps and CRT gutters in vacuum tubes
Power supply boxes, motherboards, relays and finger clips
BFRs are used to reduce flammability in printed circuit boards and plastic housings, keyboards and cable insulation
Rechargeable NiCd batteries, semiconductor chips, infrared detectors, printer inks and toners
Cooling units and insulation foam

Antimony has been classified as a carcinogen. It can cause stomach pain, vomiting, diarrhoea and stomach ulcers through inhalation of high antimony levels over a long time period
It has chronic effects that cause skin disease and lung cancer and impaired nerve signalling
Causes brain swelling, muscle weakness, damage to the heart, liver and spleen though short-term exposure
Exposure to beryllium can lead to beryllicosis, lung cancer and skin disease. Beryllium is a carcinogen
During combustion printed circuit boards and plastic housings emit toxic vapours known to cause hormonal disorders

Arsenic (As)
Barium (Ba)
Beryllium (Be)
Brominated flame retardants (BFRs): (polybrominated biphenyls (PBBs), polybrominated diphenyl ethers
(PBDEs) and tetrabromobisphenol (TBBPA))
Cadmium (Cd)

Chlorofluorocarbons (CFCs)
Hexavalent chromium/chromium VI (Cr VI)
Lead (Pb)

Mercury (Hg)
Nickel (Ni)
Polychlorinated biphenyls (PCBs)
Polyvinyl chloride (PVC)

Selenium (Se)

Plastic computer housing, cabling, hard discs and as a colourant in pigments
Solder, lead-acid batteries, cathode ray tubes, cabling, printed circuit boards and fluorescent tubes

Batteries, backlight bulbs or lamps, flat panel displays, switches and thermostats
Batteries, computer housing, cathode ray tube and printed circuit boards
Condensers, transformers and heat transfer fluids.
Monitors, keyboards, cabling and plastic computer housing

Older photocopy machines

instance, while the Basel Convention on the Control of Transboundary Movement of Hazardous Wastes and their Disposal was launched on March 22, 1989 and enforced on May 5, 1992, the
USA is one of the world’s largest e-waste producers, has not ratified this Convention or the Basel Ban Amendment. Communities are still debating the legal loophole, which permits the export of whole products to other countries provided it is not for recycling.
3. Environmental impacts of e-waste during treatment processes The presence of toxic substances in e-waste was recognised only within the last 20 years. There is inadequate legislation worldwide for effective management of such waste. The rapid growth of e-waste and the ineffectiveness of legislation has led to inappropriate management strategies in both developed and developing countries, leading to profound impacts on the environment. Management of e-waste by recycling and by disposal to landfills has been shown to pose significant risks to the environment (Puckett and Smith, 2002; Robinson, 2009; Wong et al.,
2007a). The impact of e-waste from recycling and disposal processes is summarised below.
3.1. Recycling
Vast quantities of e-waste are now being moved around the world for recycling in developing countries using manual processes in backyards of residential properties, resulting in significant con-

Cadmium compounds pose a risk of irreversible impacts on human health, particularly the kidneys
These substances impact on the ozone layer which can lead to greater incidence of skin cancer.
Is extremely toxic in the environment, causing DNA damage and permanent eye impairment
Can damage the brain, nervous system, kidney and reproductive system and cause blood disorders. Low concentrations of lead can damage the brain and nervous system in foetuses and young children. The accumulation of lead in the environment results in both acute and chronic effects on human health
Mercury can damage the brain, kidneys and foetuses
Can cause allergic reaction, bronchitis and reduced lung function and lung cancers
PCBs cause cancer in animals and can lead to liver damage in humans PVC has the potential for hazardous substances and toxic air contaminants. The incomplete combustion of PVC release huge amounts of hydrogen chloride gas which form hydrochloric acid after combination with moisture. Hydrochloric acid can cause respiratory problems
High concentrations cause selenosis

tamination of soil, water and air in these countries. Such practices have also resulted in the poisoning of many local people engaged with the recycling process. For example, Guiyu and Taizhou in China, Gauteng in South Africa, New Delhi in India, Accra in Ghana and
Karachi in Pakistan are the large e-waste recycling sites and this is where extensive pollution is emitted from the e-waste recycling processes (Asante et al., 2012; Brigden et al., 2005; Puckett and
Smith, 2002; Tsydenova and Bengtsson, 2011; Widmer and Lombard, 2005; Widmer et al., 2005). The investigations from Guiyu,
China showed POPs and heavy metals in air, dust, soil, sediment, and freshwater around the e-waste recycling site (Chen et al.,
2009; Deng et al., 2007; Leung et al., 2010; Wang et al., 2009a).
The major heavy metals released included Pb, Cd, Ni, Cr, Hg and
As. Organic pollutants emitted included PAHs, PCBs, brominated flame retardants (BFRs) such as PBDEs, and polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs), which can be formed during crude thermal processes of e-waste recycling. Polybrominated dibenzop-dioxin/furans (PBDD/Fs) may occur as impurities in PBDEs, byproducts of PBDE degradation during production, weathering, and recycling of flame-retardant plastics. It is apparent from these studies that the entire ecosystem including soil, sediment, water and air is being contaminated by these toxic substances (Table 3).
A wide range in the concentrations of total PBDEs, PAHs, PCDD/Fs and PCBs have been reported in surface soils from e-waste recycling sites. For instance PBDE ranged from 0.26 to 4250 ng/g (dry weight) (Cai and Jiang, 2006; Leung et al., 2007; Wang et al.,
2005, 2011), PAHs from 44.8 to 20,000 ng/g (dry weigh) (Leung et al., 2006; Shen et al., 2009; Tang et al., 2010; Yu et al., 2006),
PCDD/Fs from 0.21 to 89.80 ng/g (Leung et al., 2007; Shen et al.,

1240

P. Kiddee et al. / Waste Management 33 (2013) 1237–1250

Table 3
Selected toxic substances associated with recycling e-waste and their presence in the surrounding environment.
Environment

Toxic substances

Country/region

References

Soil

PBDEs

Guiyu, China

Wang et al. (2005), Leung et al. (2007) and Wang et al. (2011)
Cai and Jiang (2006)
Leung et al. (2006) and Yu et al. (2006)
Shen et al. (2009) and Tang et al. (2010)
Leung et al. (2007)
Shen et al. (2009)
Shen et al. (2009) and Tang et al. (2010)
Tang et al. (2010)
Ha et al. (2009)

PAHs
PCDD/Fs
PCBs
As, Cu, Cr, Cd, Hg, Pb and Zn
Ag, Bi, Cd, Co, Cr, Cu, In, Hg, Mn, Mo, Pb, Sb, Sn, Tl, V and Zn

Taizhou, China
Guiyu, China
Taizhou, China
Guiyu, China
Taizhou, China
Taizhou, China
Taizhou, China
Bangalore, India

Water

As, Cd, Cr, Cu, F, Fe, Hg, Mn, Ni, Pb, Zn
Ag, Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se,
Sr, Ti, V and Zn

Guiyu, China

Wang and Guo (2006)
Wong et al. (2007b)

Air

PBDEs

Guiyu, Guangzhou, Hong
Kong, China
Guiyu and Chendian, China
Thailand
Guiyu, China
Guiyu and Chendian, China
Guiyu and Chendian, China
Guiyu, China
Bangalore, India

Deng et al. (2007)

PAHs
PCDD/Fs
polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs)
As, Cd, Cr, Cu, Mn, Ni, Pb, Zn,,
Ag, Bi, Cd, Co, Cr, Cu, In, Hg, Mn, Mo, Pb, Sb, Sn, Tl, V and Zn

2009) and PCBs from 11 to 5789.5 ng/g (Shen et al., 2009; Tang et al., 2010), in Guiyu and Taizhou, China. In Bangalore, India high concentrations of Ag, Bi, Cd, Cu, In, Hg, Pb, Sn and Zn were found in soil near recycling areas (Ha et al., 2009). On the impact of e-waste on water, Wang and Guo (2006) found appreciable concentrations of Pb in surface water downstream of the recycling industry in Guiyu. The concentration of Pb was as high as 0.4 mg/l which is eight times higher than the drinking water standard in China (60.05 mg/
l). Wong et al. (2007b) reported the presence of elevated levels of toxic metals in Liangjian and Nanya Rivers compared to that in the reservoir outside of Guiyu. They found that the rivers inside
Guiyu had higher dissolved metal concentrations than those sampled outside. Therefore, recycling activities in Guiyu can be shown to adversely impact water quality surrounding this area (Wang and
Guo, 2006). On air quality, given that most e-waste disposal and recycling has been in China and other developing countries, most of the studies are from these regions with reports demonstrating major impacts of backyard e-waste disposal and recycling. Results from these studies demonstrate severe contamination of the ambient air from chlorinated and brominated compounds and heavy metals around e-waste recycling sites in China. High concentrations of heavy metals including Cr, Zn and Cu were detected at
1161, 1038 and 483 ng/m3, respectively which were 4–33 times higher than those in other Asian countries and PAHs contained in
TSP and PM2.5 were found at 40–347 and 22.7–263 ng/m3, respectively (Deng et al., 2006). PBDEs associated with TSP and PM2.5 were detected at 124 and 62.1 lg/m3, respectively while the high pollution levels of PBDEs in Guiyu were 58–691 times higher than at other urban sites (Deng et al., 2007). The concentrations of
PBDD/Fs were found to be at 8.12–61 pg/m3. Moreover, PCDD/Fs in Guiyu were detected at 64.9–2365 pg/m3 and these are the highest concentrations in ambient air worldwide (Li et al., 2007). Early reports implied that the air pollution in Guiyu has also been traced to e-waste recycling plants. In Bangalore, India high levels of Bi, Co,
Cr, Cu, In, Mn, Pb, Sb, Sn and Tl were found in air around recycling areas which were higher than the levels around reference sites (Ha
P
et al., 2009). In addition, in Thailand the level of PBDEs (BDE-17,
28, 47, 49, 66, 85, 99, 100, 153 and 154) in the indoor air of an ewaste storage facility were found at 46–350 pg/m3 whereas in outdoor locations, air pollutants were found at 8–150 pg/m3 which were lower than the levels of PBDEs in China (Muenhor et al.,
2010).

Chen et al. (2009)
Muenhor et al. (2010)
Deng et al. (2006)
Li et al. (2007)
Li et al. (2007)
Deng et al. (2006)
Ha et al. (2009)

These findings confirm that significant levels of potentially toxic substances released during the recycling processes are building up in the environment. The potential hazards of persistent inorganic and organic contaminants (such as toxic PCBs, PBDEs, and metals) to the ecosystem and human health are expected to persist for many years to come. Moreover, weathering of organic contaminants is likely to result in the formation of metabolites that could potentially be more toxic than parent compounds. One such example being the debromination of DecaBDEs by photolytic
(Söderström et al., 2004) and anaerobic degradation reactions
(Gerecke et al., 2005) which gives rise to highly toxic congeners.
It is apparent from published studies that much effort during the past decade has been directed towards surveys conducted to determine the nature of toxic substances associated with e-wastes and the presence of these in the environment with a limited number of studies focussing on human health. There is limited information, however, on the impact of e-wastes on environmental health especially their impact on terrestrial and aquatic ecosystem.
3.2. Landfill disposal
Irrespective of the current global move towards zero wastes, the number of landfills has been increasing in both developed and developing countries. While the owners of modern landfills argue that recently constructed landfills are capable of safely isolating from the environment the pollutants found in electronics (SWANA,
2004), the presence of thousands of old landfills with no barrier and containing a mixture of putrescibles and e-wastes is of much concern. There is sufficient evidence now to demonstrate that landfills accepting electronic devices or old landfills containing ewastes will cause groundwater contamination (Schmidt, 2002;
Yang, 1993). Pollutants have the potential to migrate through soils and groundwater within and around landfill sites (Kasassi et al.,
2008). Organic and putrescible material in landfills decomposes and percolates through soil as landfill leachate. Leachates can contain high concentrations of dissolved and suspended organic substances, inorganic compounds and heavy metals. However, the concentrations of toxic substances from leachate depend on the waste characteristics and stages of waste decomposition in a particular landfill (Qasim and Chiang, 1994).
One measure designed to assess the potential toxicity of leachates from e-waste disposal is Toxicity Characteristic Leaching Pro-

1241

P. Kiddee et al. / Waste Management 33 (2013) 1237–1250
Table 4
Leachate from electronic devices under laboratory-based TCLP conditions.
Devices

Unit a Cellular phones
CRTs – TVsb
CRTs – computersb
CPUsc
Laptopsc
Cellular phonesc
Keyboardsc
Computer micec
Remote controlsc
Smoke detectorsc

Ag

As

Ba

Cd

Cr

Hg

Pb

Se

mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l 0–0.010 na na na na na na na na na 0.056–0.067 na na na na na na na na na 1.46–2.88 na na na na na na na na na 0.0006–0.006 na na na na na na na na na 0.04–0.13 na na na na na na na na na 0–0.010 na na na na na na na na na 38.2–147.0
16.5
19.3
0.7
37.0
20
2.4
19.8
17.0
23.0

0.073–0.12 na na na na na na na na na na: Not available.
Sources:
a
Lincoln et al. (2007). b Musson et al. (2000). c Townsend et al. (2004).

cedure (TCLP) which simulates landfill leaching in terms of a worst case eventuality. A number of electronic devices were subjected to tests by laboratory based TCLP (Table 4). TCLP test helps to determine if a solid waste processes physical and chemical properties that make it a toxicity characteristic (TC) hazardous waste. Electronic devices are considered to be TC hazardous waste under provision of the Resource Conservation and Recovery Act (RCRA) if the devices contain specific elements higher than TC regulated concentrations, which are 5 mg/l of As, 100 mg/l of Ba, 1 mg/l of Cd, 5 mg/l of Cr, 5 mg/l of Pb, 0.2 mg/l of Hg, 1 mg/l of Se and 5 mg/l of Ag
(Townsend et al., 2005).
There have been a number of studies to investigate the leachability of components that comprise e-waste. Lead from cathode ray tubes (CRTs) in televisions and computer monitors is one of a number of toxic substances that can leach to the wider ecosystem
(Musson et al., 2000). Jang and Townsend (2003) compared leachates from eleven Florida landfills to determine Pb leachability from computers’ printed circuit boards and cathode ray tubes from computers and televisions using the TCLP test. They found that the concentration of Pb in TCLP extracts ranged from 0.53 to 5.0 mg/l in printed circuit boards and 1.7 to 6.0 mg/l in cathode ray tubes whereas Pb in landfill leachates were detected from