A wide variety of materials, compounds and components are found in WEEE. The state of knowledge regarding types, amounts and potential dangers associated with these has improved considerably over the past decade, yet remains well below 100%. As a result, research and studies emanating from Europe, the USA and Australia typically recommends caution and vigilance for policy makers and industry with a view to minimising potential environmental problems associated with WEEE (e.g. Nordic Council of Ministers, 1995; Swedish Environmental Protection Agency, 2001; Five Winds International, 2001; Environment Australia, 2001; Enproc, 2001). Many studies also highlight methodological limitations associated with the research to date.
The studies cited represent work conducted by or for government agencies, research institutions, universities and specialist consultants.
A report by the Swedish Environmental Protection Agency - Electronic and Electrical Equipment: The Basis for Producer Responsibility (1995) makes several observations and conclusions in relation to WEEE:
- Electronic and electrical products have a significant impact on the environment when they are manufactured, when they are used and when they reach the end of their life and are discarded.
- Hazardous substances can be found in all groups of products, although their presence and identity are difficult to ascertain owing to the frequent lack of environmental product information sheets.
- Sorting and disassembly are necessary in most cases to remove hazardous substances and materials for safe disposal and so other materials can be recycled or dealt with in an appropriate manner.
- It is important that recycling of WEEE leads to real environmental gains instead of merely changing the nature of the environmental problems faced. The EPA therefore considers that end-of-life EEE should be dismantled to remove hazardous components, which should then be disposed of in a secure manner.
- Stringent requirements should be set in respect of the design and location of sites for the disposal of cathode ray tubes.
- Production of raw materials consumes natural resources in the form of minerals, oil, etc. Extraction results in emissions to air, water and the creation of waste. If more material from end-of-life EEE could be recycled in an environmentally satisfactory manner, emissions associated with extraction of raw materials would decrease and natural resources would be saved.
- It is not clear how different processes at a landfill site affect metals and chemicals in landfilled EEE. However, it may be assumed that in time most of these substances will leach out.
- Particularly hazardous substances should not be allowed to enter the environment. The aim should be that materials and components containing printed circuit boards and other organic pollutants possessing similar properties should not be landfilled until these compounds have been destroyed.
- A fundamental aim should be to recycle metals to the greatest possible extent. Where metals are not recycled they should be landfilled. As far as possible metals should not be incinerated.
- A minimum precautionary measure is to sort out the most environmentally harmful components for safe disposal when end-of-life EEE is collected and sorted.
- Cathode ray tubes contain fairly large quantities of lead oxide in the cone glass and a multitude of other substances, which may be hazardous in the fluorescent layer. There is no reliable information on the rate at which this lead leaches.
- Stringent requirements should be made of the design and location of sites at which cathode ray tubes are to be landfilled in order to minimise the risk of leaching and dispersal of lead and other hazardous substances.
Two particularly relevant studies undertaken by the Nordic Council of Ministers focus a range of specific environment impacts, issues and concerns with WEEE. The first study - Waste from Electrical and Electronic Products - a survey of the contents of materials and hazardous substances in electric and electronic products (1995), concludes the following:
- The lead content of cathode ray tubes is of concern mainly because the material volumes are so large. It can be noted that glass is dissolved very quickly in bases, but very slowly in acids. This makes the currently used TCLP test to measure dissolution rate, where acids are used, of highly questionable value to assess leaching rates from CRTs in basic environments.
The second Nordic Council report - Environmental Consequences of Incineration and Landfilling of Waste from Electr(on)ic Equipment (1995b) is even more focused in its conclusions on WEEE impacts:
- Some materials in WEEE are hazardous to the environment. Other substances are not hazardous in the concentrations present. The amount of material has to be considered when discussing environmental impacts. Some substances in WEEE are in small quantities, but can be very poisonous.
- When WEEE is mixed with other types - especially organic waste - in landfills, the substances change their mobility and toxicity. Generally emissions will increase, but it is very difficult to estimate all the environmental impacts.
- The processes in landfills are very complicated and run over a wide time span. Therefore, it is impossible to quantify environmental consequences of WEEE in landfills.
- At present it is not possible to state negative environmental impacts from controlled landfills caused by WEEE. On the other hand, the processes are so complicated that it would be a mistake to neglect the possible risks.
- Degradation of CRT-glass in landfills is a very slow process, but eventually barium and lead will be leached from the glass. If CRT-glass contains cadmium as a pigment, the cadmium may also be leached.
- As a general rule, sorting waste from electric and electronic equipment and extracting of as many metals as possible especially copper, nickel, lead, and mercury before incinerating and landfilling should be recommended.
More recently a report by Five Winds International for the Canadian Government (Environment Canada) - Toxic and Hazardous Materials in Electronics. An Environmental Scan of Toxic and Hazardous Materials in IT and Telecom Products and Waste (2001), notes the following issues:
- Toxic and hazardous materials are present in IT and telecom products. The use of some toxic and hazardous materials in each unit is declining, but this is being offset by sales growth in these sectors and the introduction of new uses for toxic and hazardous materials (e.g. beryllium).
- There is a risk that toxic or hazardous materials present in IT and telecom products will be released to the environment during recycling, landfilling or incineration.
- The substances examined in this study are reported as not being released from IT and telecom equipment during manual disassembly.
- Many major OEMs are making progress in reducing and eliminating toxic or hazardous materials from their products. The key drivers are actual or anticipated regulations by governments and customers (especially in Europe and Japan), and their own environmental policies.
- The focus of OEM initiatives appears to be on eliminating lead solder and brominated flame-retardants from their products. This is driven, at least in part, by the EU WEEE Directive.
- Supply Chain Management is critical for OEMs to control and manage toxic and hazardous materials in their products. This has become even more important in recent years as the trend towards outsourcing electronics manufacturing continues.
- Japanese OEMs are leading in eliminating lead-containing solder from their products.
One of the more widely read documents directly influencing the need for increased policy and legislative attention to WEEE impacts is the European Commission's Proposal for a Directive of the European Parliament and of the Council on Waste Electrical and Electronic Equipment (2000). This document effectively provides the impetus for the EU WEEE and RoHS Directives and offers considerable information about WEEE impacts and issues:
- Today, more than 90% of WEEE is landfilled, incinerated or shredded without any pre-treatment. This leads to a considerable emission of the targeted substances into the environment. Usually small WEEE, which can be disposed of with the ordinary waste, goes directly to incineration or landfill.
- The risks relating to placing discarded electrical equipment in landfill are due to the variety of substances they contain. The main problem in this context is the leaching and evaporation of hazardous substances.
- Due to the variety of different substances contained in EEE, unknown toxic hazards are created during landfilling of WEEE. When co-disposed with municipal waste, there is the potential, particularly given rainwater and groundwater processes, of unknown toxic mixtures leaching out into the environment. The potential amounts and concentrations - and resulting environmental impacts - are considerably higher when WEEE is put in uncontrolled landfills, which still takes place to a significant extent in certain Member States.
- Leaching of mercury takes place when certain electronic devices, such as circuit breakers are destroyed. When brominated flame retarded plastic or cadmium containing plastics are landfilled, both PBDEs and cadmium may leach into the soil and groundwater. PBBs have been found to be 200 times more soluble in a landfill leachate than in distilled water. This may result in wider distribution in the environment.
- As regards mercury, both the leaching of elemental mercury and the vaporisation of metallic mercury and dimethylene mercury, both contained in WEEE, are of concern.
- Leachate collection and treatment of controlled landfills respecting current best practice technical standards, such as those set out in Directive 99/31/EC, does not completely eliminate exposure nor does it solve all the problems of WEEE. High standard landfills collect leachate in controlled and sealed systems. In these cases the leachate is collected and sent to treatment plants on site or to municipal sewage treatment plants, where it must be contained and further processed.
- Apart from the situation relating to the management of controlled landfills, it should be noted that a number of landfill sites do not apply best available technologies concerning emission controls. It is not likely that the majority of uncontrolled landfilled sites will be completely replaced, in the short and middle term, by high standard landfill sites in all parts of the Community.
- In the case of uncontrolled landfills contaminated leachate goes directly to the soil, groundwater and surface water. Leachate containing the above pollutants from uncontrolled landfills could contaminate water to an extent that its use as drinking water is impossible on the basis of the limits set out in Council Directive 80/778/EEC relating to the quality of water intended for human consumption.
- Through present WEEE management systems, valuable materials are disposed of and lost to future generations through the present methods of waste management of discarded electrical products. Along with the loss of resources, substantial pollution of the environment from mining is of concern. It is not possible to give exact figures on the environmental impact of the extraction of all the materials contained in electrical and electronic equipment. This depends very much on the site and region where the materials are extracted. However, the process leading to the extraction of these metals and their general impact on the environment is well known and documented.
In 2004 the UK Department for Environment, Food and Rural Affairs (DEFRA) commissioned AEA Technology to look specifically at identifying the products and components of present and historic waste from electrical and electronic equipment. The report - WEEE and Hazardous Waste, presents some noteworthy findings especially in relation to information availability and information gaps:
- An extensive review of published literature has been carried out to determine the range of typical components found in equipment and the composition of various types of equipment. This has been moderately successful in covering the more common types of WEEE (representing greater than 80% of this waste stream), however, there still remains a significant proportion of WEEE that falls in the 'unknown' area.
- Where information on a product/component is unknown, treatment facilities face difficulties in identifying what is and what is not hazardous. Although this issue will be resolved in time through the information provision requirements of Article 11 of the WEEE Directive, practical dismantling and analysis trials on historic WEEE are needed to address this knowledge gap.
- On the basis of our assessments, the results obtained confirmed that the removal and treatment requirements of Annex II of the WEEE Directive were generally in line with the HWD. It would appear that the 'Precautionary Principle' has been applied in requirements to remove circuit boards, plastics containing brominated flame retardants (BFRs) and electrolyte capacitors (>L/D 25mm) containing 'substances of concern' because threshold criteria for certain BFRs (which can be present in significant proportions) have not yet been fully determined and 'substances of concern' have not been defined. Clarification is needed on the hazardousness and appropriate treatment of these items.
- The results also found that some other components that are not specified in Annex II may be hazardous, and may need to be removed to render the WEEE item non-hazardous. These include plastics and rubbers containing phthalate plasticizers or lead stabilisers, lithium batteries, and components containing mineral wools that come under the classification as a category 3 carcinogen.
Research from the University of Florida has also contributed to the discussion on WEEE related impacts with a particular focus on lead leachability in landfills. These studies - Assessment of True Impacts of E-Waste Disposal in Florida (2003), and RCRA Toxicity Characterization of Computer CPUs and Other Discarded Electronic Devices (2004) - offer the following observations:
- The US EPA has been examining the applicability of the TCLP (Toxicity Characteristic Leaching Procedure) and this research adds to this complicated issue. For those state and local government agencies wrestling with whether to ban discarded electronics from landfills, the results of this work suggest that lead leaching from PWBs and CRTs in one landfill studied may be less than might be estimated using TCLP results. It should be noted that this was a short term study and does not provide evidence of long term processes in landfills. It is also important to note that other factors affect the migration of leached lead from a disposed device to the leachate collection systems of a landfill (e.g. sorption, reduction, precipitation).
- The testing of entire colour computer monitors and colour televisions confirms previous experiments that show colour CRTs can leach lead above the toxicity characteristic concentration. Small electronic devices that contain a PWB with lead solder often leach above 5mg/L of lead using the standard TCLP. When larger devices were tested using the modified large-scale method, they often exceeded the TC limit for lead. The amount of ferrous metal present in some of these devices may result in less lead being leached if the standard TCLP were to be performed.
- Size-reduced computer CPUs leached less lead than the same model of CPU leached with the large-scale modified method (it should be noted that this particular model did not fail TCLP even for the large method, while many of the other CPU models tested did). On the other hand, in limited testing of laptops using the standard approach and modified approach, the TC limit was always exceeded for lead. The difference between leaching results for the two devices likely resulted from the greater ferrous metal content (68%) of the computer CPUs relative to the laptops (7%).
The following tables provide an overview of post consumer electronics in terms of product types and componentry and reported concerns about toxic and/or hazardous substances.
Apart from in batteries, lead is used widely in solders, as an alloying element for machining metals, printed circuit boards, components, incandescent light bulbs, and weighting. Lead oxides occur in leaded glass in cathode ray tubes, light bulbs and photocopier plates, and in batteries. Lead-based solder (typically a 60:40 ratio of tin to lead), which is used to attach electrical components, represents the major solder type used in most EEE applications and typical motherboards have been reported to contain approximately 50 g/m2 lead (Five Winds International, 2001). In CRTs, leaded glass provides shielding from X-rays generated during the picture projection process. Color CRTs contain 1.6 kg to 3.2 kg of lead on average (Microelectronics and Computer Technology Corporation, 1996). A TV set glass contains about 2 kg lead (European Commission, 2000). The lead oxide in CRTs tubes constitutes the largest share of lead in WEEE, where it is present in the form of silicates. A light bulb contains between 0.3 and 1.0 g of lead in lead-tin solder and 0.5 to 1.0 g of lead silicates in the glass (on average 1.5 g lead in solder and glass). In Sweden this application amounts to the use of about 100 t of lead annually.
The global man-made release of mercury to the atmosphere is approximately 2000-3000 tonnes per year. It is estimated that of the yearly world consumption of mercury 22% is used in EEE (AEA, 2004). Mercury is basically used in thermostats, sensors, relays and switches (on printed circuit boards and in measuring equipment and discharge lamps). Furthermore, it is used in medical equipment, data transmission, telecommunications, and mobile phones. In the EU, 300 tonnes of mercury are used in position sensors alone.
It is known that in Printed Circuit Boards cadmium occurs in certain components, such as chip resistors, infrared detectors and semiconductors (European Commission, 2000). Older types of CRTs contain cadmium. Furthermore, cadmium has been used as a stabiliser in PVC. Cadmium metal or powder is still used as part of the negative electrode material in nickel-cadmium (NiCad) batteries, as an electrodeposited, vacuum deposited or mechanically deposited coating on iron, steel, aluminium-base materials, titanium-base alloys or other non-ferrous alloys, and as an alloying element in low-melting brazing, soldering and other specialty alloys (AEA (2004). Cadmium oxide forms part of the negative cadmium electrode in nickel-cadmium batteries, and cadmium sulphide is found widely in CRT and electronic devices.
Very little information on the uses of hexavalent chromium in IT and telecom equipment exists in the literature. Hexavalent chromium is used in the plastics of personal computers, cabling and packaging. Chromium VI is typically used as a hardener or stabilizer for plastic housings and as a colorant in pigments. References to quantities of chromium VI in these components are poor (Five Winds International, 2001). The use that is occurring seems to be in trace amounts, between 0.2 and 0.3 grams per component. As a colour pigment, the European Union is moving to restrict the use of chromium VI. Hexavalent chromium may also be present on the surface of metal parts that have been protected from corrosion with chromate conversion coatings - no references to quantities of Cr VI present in this application were found.
Beryllium metal offers a unique and incomparable combination of properties. It is one of the lightest structural materials available but is several times stronger than steel. It has excellent thermal conductivity, high electrical conductivity, good corrosion resistance, good fatigue resistance, high strength and good formability. Traditionally, copper-beryllium alloys were used in motherboards on personal computers. Beryllium is rarely used in this form anymore, but its use in combination with copper as an alloy is increasing (Five Winds International, 2001). Beryllium improves the properties of copper contact springs because of its high strength, high conductivity and high elastic quality. Between 2 - 4% of these copper alloys is beryllium metal. Beryllium metal is sometimes overlooked as one of the components of concern in end-of-life electronic equipment. It is used amongst other things, in electrical insulators and resistors, microwave tubes, photographic equipment, rotating mirrors in laser printers, and both beryllium and beryllium oxide are used in heat sinks.
Brominated flame retardants (BFRs) are today regularly designed into electronic products as a means for ensuring flammability protection, which constitutes the main use of these substances. The three main groups of PBDEs, which are currently commercially available, are penta-, octa- and decabromodiphenythether. BFRs are used in a wide range of products including plastics, white goods, car interiors, carpets and carpet underlay, polyurethane foams in furniture and bedding. They occur in EEE in mainly four applications; PCBs, components such as connectors, plastic covers, and cables, and their use has increased markedly over the past two decades, with worldwide production over 200,000 tonnes per year. According to a Danish estimation, WEEE represents about 78% of the total content of brominated flame retardants in waste (European Commission, 2000).
Tetrabromobisphenol-A (TBBPA) is the largest volume brominated flame retardant in production today. It is used as a reactive (primary use) or additive flame retardant in polymers, such as epoxy and poly-carbonate resins, high impact polystyrene, phenolic resins, adhesives, and others. Its main use in EEE is as a reactive flame retardant in printed circuit boards. Further commentary on the contemporary use and toxicity evidence of BFRs is provided in section 4.6.
Many different types of plastics are used in the manufacture of electronic equipment. PVC is ubiquitous in electronics, forming the structure of computer housings, keyboards and cables. Estimated quantities of PVC in different products range from 37.1 grams in a keyboard to a total of 314 grams in all of the cables connecting different component pieces together (for example, the cables connecting the monitor, mouse and keyboard to the CPU) (Five Winds International, 2001).
The predominant use of PVC plastic in electronics is as a structural feature in plastic computer housings, keyboards and cables. PVC has good chemical resistance that original electronic equipment manufactures look for when designing durable products.
Phosphors are found in all CRT screens as well as fluorescent lights. Many phosphors used in CRTs contain zinc, although only small quantities of phosphors are used in electrical and electronic products. Some phosphors can contain terbium. However, little is known of terbium's toxicity. Some old monitors contain phosphors that include arsenic (Environment Australia, 2001).
At a product and substance specific level, work conducted by Five Winds International Five Winds International (2001) provides a relatively detailed overview of specified IT and telecommunications products (and components) and the presence of particular toxic and hazardous substances.
The Five Winds report describes substances across specific products and components including reference to various factors, for example:
Table: Mercury in IT and Telecom Equipment
Fluorescent lamps - flat screen laptop displays
Back light for LCD
Manufacturers must report any intentionally added mercury
Banned in all uses except lamps (EU)
The report provides this level of information across numerous relevant EEE products and components for the following substances:
- Hexavalent Chromium
- Brominated Flame-Retardants
- Polyvinyl Chloride - PVC
- Polychlorinated Biphenyls.
The detailed tables relating to the above can be found under Section 2: Toxic and Hazardous Materials in IT and Telecom Products (pp7 - 24). The report is available to download from: http://www.fivewinds.com/publications/publications.cfm?pid=75.