Wednesday, December 9, 2009

What Are You Leaving Behind?

When you move on to the latest technology, what happens to the items you leave behind? 
Well, it gets added to the 4,750 tonnes of lead, 4.5 tonnes of cadmium, and 1.1 tonnes of mercury contained in personal electronics that are disposed in Canada each year, according to Environment Canada [1].  These figures are grossly underestimated.  

Slightly more than half of the metals that are found in a typical desktop computer include copper, aluminum, lead, gold, zinc, nickel, tin, silver, and iron, while the remaining portion is composed of platinum, palladium, mercury, cobalt, antimony, arsenic, barium, beryllium, cadmium, chromium, selenium and gallium [2]. One of the reasons we don't want old electronics to end up in landfills is because toxic metals such lead and mercury can leach into the water and soil, and eventually circulate throughout the food chain, and possibly end up in our bodies [2]. While equipment is intact, these heavy metals don't pose a risk to human health, but when electronics are discarded and/or recycled in uncontrolled environments, the hazardous components are released into the environment posing great amounts of risk [2,3]. Despite the fact that most heavy metals are toxic and bioaccumulative at low concentrations, the main heavy metals investigated in the e-waste disposal literature that I found were lead, beryllium, cadmium and mercury.

Health Risks of Lead Exposure
Lead is one of the most commonly used heavy metals -- it is used in both computer and television screens, and in the solder used to anchor various circuit board components. Toxicity tests of laptops, VCRs, printers and remote-control devices have been conducted in the US, and found that a substantial proportion of these electronics exceeded the US safety standards for lead [3].  The main reason for having a product safety standard for lead is because its deleterious effects on human health have been widely studied, and are well known to be quite serious.  According to Health Canada, short term exposure to high levels of lead can cause vomiting, diarrhea, convulsions, coma or even death. The main areas of the body affected by lead are the brain, kidney, and nervous system [4]. Once exposed to lead, it can remain in your body for years in bone or circulating through the blood stream [5]. Children are particularly susceptible to lead at even lower levels of exposure, due to increased absorption. The harms noted in children include impacts on intellectual development, behaviour, size and hearing. During pregnancy, lead can also cross the placenta and affect the unborn child. Studies have shown that female workers who are exposed to high levels of lead have more miscarriages and stillbirths [4,5].  In Canada, corrective action is taken when patients present with blood lead levels exceeding 10 micrograms per decilitre [4]. Recent studies have shown that blood lead levels lower than 10 micrograms per decilitre were associated with reduced IQ scores and academic skills [6]; therefore, no level of exposure has been deemed safe.

Health Risks of Beryllium Exposure    
Beryllium is sometimes used in circuit boards as an electrical connector and/or to insulate microprocessors [2].  When improperly handled during disposal or recycling, beryllium dust can be released, which is known to cause severe lung disease and lung cancer [6,7]. Exposure thresholds have not been accurately set for beryllium in Canada, according to a recent risk assessment for generic e-waste processing facilities in Canada [8]. Interestingly, this Canadian risk assessment found exposure levels to both lead and beryllium to be above the occupational exposure limits outlined by the ACGIH. The current occupational exposure limit in Ontario is 0.002 micrograms per meter cubed (time–weighted average exposure value) [9].  

Health Risks of Cadmium Exposure
The predominant use of cadmium is in rechargeable batteries. In addition to this, cadmium can be found in plastics, cadmium plated steel, solders, and TV picture tubes [10]. Cadmium toxicity can lead to kidney, bone, and pulmonary damage. There are three modes of exposure: dermal, pulmonary (lungs), and gastrointestinal (mouth); cadmium cannot cross the placenta. The main organ for long-term cadmium accumulation is the kidney, hence its toxic effects on the kidney with life-time exposure [11]. Acute toxicity due to cadmium exposure can lead to nausea, vomiting, weakness, shortness of breath, lung edema (fluid in the lungs) and possibly death [11,12].  Chronic exposure has been linked to kidney damage, bone mineral density loss and hypertension [13]. Additionally, the International Agency for Research on Cancer classifies cadmium as carcinogenic, with exposure primarily linked to lung cancer [14]. Currently, there is no Canadian blood cadmium guidance value for the general population; although, according to the preliminary results from the new Canadian Health Measures Survey, the geometric mean blood cadmium in Canadians aged 6 to 79 was 0.35 micrograms per litre [13]. 

Health Risks of Mercury Exposure
An estimated 22 percent of the mercury used world-wide each year goes into electrical and electronic equipment, including batteries, flat-panel display screens, and switches [15]. Even though very small amounts of mercury are used in these products, very small levels of mercury exposure are known to cause damage to the brain, spinal cord, kidneys, liver and a developing fetus. The human health risks of mercury exposure have been recognized for quite some time, and consequently is a well researched area.  To date, mercury exposure is understood to have neurological, renal (kidney), cardiovascular and immunological impacts.  In extreme cases, long-term exposure can lead to coma or death. Neurodevelopmental problems in children can also develop as a result of mercury exposure while in the womb [16,17].  Recent studies have noted adverse health events occurring at even lower mercury exposure levels [16].  The Health Canada guidance value for total blood mercury concentrations is 20 micrograms per litre for adults (a threshold value has not been set for children) [17].


  1. Now I feel really guilty about throwing away batteries. How are we supposed to dispose of them??

    My town had a huge push on what to recycle, compost, or put in the garbage. I think there needs to be a bigger emphasis on a fourth category: toxic!

  2. I completely agree Mark. You've pointed out a really important gap in the current waste disposal industry that I'm hoping will get addressed in the near future.

    I would suggest that you read my other post entitled "Do What You Can.Ca". It's about a new program that is slowly being implemented in Ontario. I'd be interested to hear what your thoughts are. Also, check out this website:, which should help you find a place in your neighborhood where you can safely dispose your old batteries.

  3. You note that the figures are gross underestimates – can you say explain why, or indicate that you will explore why in this post? Good referencing into established literature. Making sure to distinguish life stage and other vulnerabilities is very important e.g. mercury only an adult level, no child one!

  4. I am intrigued with what people have to say about their old electronic gadgets. There are those that still keep them even if they have the latest models while others do not put much thought into and and simply throw them in the bin. We tend to forget that disposing them is not like our paper documents which we can just have shredding Austin companies collect. Electronic items that are being thrown need to be collected and brought to facilities that can re-purpose them in an eco-friendly way.

  5. HI am ultrust from india i am a E-waste recycler is e-waste Management Company in India. Our e-waste recycling company recycles electronic and electrical waste, toner cartridge or anything that runs on electricity or battery. "Electronic waste" may be defined as discarded computers,

  6. is India's 1st environmental B2B portal.It is an online one stop go Green source to provide end to end solutions for environment protection, pollution control management, energy conservation, renewable energy, e-waste management and safety management. also provide Green News, live discussion, Blogs, Environment friendly calculator, Games with Learn and much more interesting and educational section.