Cadmium – the new lead?

July 26, 2011

Health Canada has just proposed a limit on cadmium in children’s jewelry of 130 ppm (0.013%), which is lower than the limit for lead concentrations. This limit was imposed because after a limit was established for lead, manufacturers started using cadmium instead. Several pieces of jewelry tested over the last couple of years have been almost pure cadmium, but in most cases these items remained on the market because there is currently no regulatory mechanism by which Health Canada can force them to be recalled and the sellers refused to voluntarily recall them (and yet there is still a lot of political resistance to proposed regulations that would give Health Canada the power to force a recall…).

So what’s the concern with cadmium, and is it really more toxic than lead? Read on…

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Salt consumption and the media

July 21, 2011

A good post at Science-Based Medicine today about how the media managed to completely misinterpret a meta-analysis of studies on salt effects.

Yes, I’ve been pretty slack about posts lately – summer is pretty short here so I should spend the time outside rather than sitting at my computer.


Cell phones and cancer – revisited

July 4, 2011

ResearchBlogging.orgA few weeks ago the classification of radiofrequency electromagnetic fields (RF-EMF, the radiation from cell phones) as a possible human carcinogen by the International Agency for Research on Cancer (IARC) made headlines. At the time, my position was that it is hard to draw conclusions from a press release, but that given the criteria for classification as a possible human carcinogen, the information in the press release and the data available in the scientific literature I didn’t see a need to panic.

Now more technical information about the IARC evaluation is available, published in the Lancet; while it still isn’t the full IARC technical monograph (which we probably won’t see for several months at least) it does provide a bit more insight into the basis for the IARC classification. At virtually the same time, another analysis of the same data by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) Standing Committee on Epidemiology has been published, which concluded that “the accumulating evidence is increasingly against the hypothesis that mobile phone use can cause brain tumours in adults.” Which of these two apparently conflicting conclusions should we believe? Read the rest of this entry »


Classification of formaldehyde as a human carcinogen

June 20, 2011

There have been a few reports in the news recently about how the US government has added formaldehyde to their list of substances known to cause cancer in humans. This doesn’t really come as a surprise – the International Agency for Research on Cancer (IARC), for example, already classifies formaldehyde as a confirmed human carcinogen. But since there’s some media attention on the subject right now, and since formaldehyde exposure can occur from a variety of sources, including many consumer products, it seems a good time to look at what this classification means for the general public.

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Methylmercury and fish consumption

June 9, 2011

After a bit of a break, I’m getting back to my series of posts related to mercury. This time I’ll focus on methylmercury, which is generally considered to be one of the “nastier” forms, since it is relatively toxic (primarily neurotoxicity, but also believed to cause cardiovascular and reproductive toxicity at high doses) and also bioaccumulates in animals. Since the main source of methylmercury exposure is food, and in particular fish, I’ll look at how the amount of mercury in fish relates to potential effects on humans.

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The cellphone cancer controversy

June 1, 2011

The news yesterday and today has been full of reports that the World Health Organization – or more specifically the International Agency for Research on Cancer (IARC) is reporting that cellphones could cause cancer. The reaction is based on a press release; the full IARC evaluation has not yet been released. Based on what is in the press release, should we be worried?

The physics of how electromagnetic fields from cellphones interact (or don’t interact) with the human body is not my area of expertise, so I’ll leave the discussions about the plausibility based on known or suspected mechanisms of carcinogenicity – the energy from cellphones doesn’t break chemical bonds in DNA, but that doesn’t mean there is absolutely no possible mechanism of carcinogenicity. Rather, I’ll look at what the IARC press release is really telling us, which is not necessarily the same thing as how the media are spinning it.

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Health effects from chemical exposures – not just a modern phenomenon

May 29, 2011

When we think about exposures to chemicals causing adverse effects on human health, there is a tendency to view this as a product of modern industrial societies. To some extent this is true – there are certainly potentially hazardous chemicals we are exposed to as a result of our lifestyles, such as volatile chemicals in paints and solvents, the gasoline used to fuel our vehicles, and products of the combustion of tobacco. Most of the instances where we can clearly associate an adverse health effect with a particular chemical exposure are from workers in factories and chemical plants.

However, a new paper by Sebastian Wärmländer and colleagues examines a much older case of exposure to harmful chemicals – specifically aboriginal populations in California starting around 10,000 years ago exposed to polycylic aromatic hydrocarbons (PAH).

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