A new study has been appearing in news reports over the past couple of days: a group of researchers found that children drinking water with high levels of manganese had lower IQs than children drinking water with lower levels of manganese. Obviously no parent wants their children to have a lower IQ, but the media reports don’t really provide much information on whether this study indicates any sort of risk to the general population, so I thought I’d take a more in-depth look at the study in the context of what we know about manganese in drinking water supplies.
Every day, millions of people in North America, and possibly billions worldwide, deliberately expose themselves to a mixture of toxic chemicals. Over 1000 different chemicals have been identified in this mixture; while many of these chemicals have not been studied in detail, of those that have, almost 80% have been found to be carcinogens. The mixture includes potent carcinogens such as benzene, benzo(a)pyrene, acrylamide furans, benzofurans, isoeugenol, and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline. It also includes hydrogen peroxide, as well as a host of chemicals with names like 4-hydroxy-3-methoxybenzaldehyde and 3-methylcyclopentante-1,2 dione(3-methyl-2-hydroxycyclopent-2-ene-1-one). Most people consume more carcinogens from this mixture in a single day than their entire exposure to pesticides from eating non-organic fruits and vegetables for a year.
What is this mixture and why is no one doing anything about this?
Three new “ahead of print” articles in Environmental Health Perspectives look at potential health effects from swimming in pools with chlorinated water. One study (by Richardson et al.) identified the disinfection by-products present in chlorinated and brominated swimming pool water, and related them to mutagenicity. A pair of related studies looked at biomarkers of genotoxicity/carcinogenicity (Kogevinas et al.) and respiratory effects (Font-Ribera et al.). Among other conclusions, the authors of the studies stated that swimming pool water is mutagenic and genotoxic. So, what do these studies tell us, and do they mean we should be worried about swimming in chlorinated water?
A large Canadian study is underway looking at causes of cancer, and they need volunteers. It just takes a little bit of time (plus some blood and urine samples), and the results will hopefully help with cancer prevention in the future. If you live in Canada and are between 35 and 69, you can find the branch of the study in your province at the Canadian Partnership for Tomorrow Project.
A couple of weeks ago I discussed measurement of chemicals in blood and urine and what it actual means; as part of the post I did a quick “back of the envelope” calculation to relate the BPA (bisphenol A) concentrations in urine that had the media so worked up to estimated exposure doses and what regulatory agencies consider to be a safe dose. Well, in the new issue of Regulatory Toxicology and Pharmacology, researchers from the Université de Montréal, Health Canada and Summit Toxicology published a paper attempting the same thing, only using a more rigorous approach. How did my quick calculation stack up?
I’m back from vacation and ready to get back to work on this blog. I’ve got lots of ideas – it’s just a matter of finding the time to put them into words (I’ll try to get something up this evening).
Now that I’ve been writing this blog for a few months and have a better feel for where I’m going with this, I’ve decided it’s time to give this blog a name that better represents the content. I went with ‘exposure/effect’ as a simple title that represents two of my main areas of interest and expertise: how much of chemicals we are exposed to, and what are the effects of these exposures. It also evokes one of the basic risk assessment equations: exposure divided by the allowable or safe dose (‘effect’) equals hazard or risk.
While I was at it I changed the theme from the old WordPress default to another theme that still looks fairly clean and professional. I’ll still retain the ‘ashartus’ pseudonym for posts, and keep the same URL.
Do you like the new title and theme? I welcome comments and feedback.