Department of Chemistry

Visiting Speaker

Professor Ken Reimer

Royal Military College of Canada, Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Kingston, Ontario K7K 7B4, Canada  (email: reimer-k@rmc.ca)

Will present a seminar titled:

“Arsenic in the Environment and Consumer Products”

The media regularly reports the presence of arsenic in consumer products such as children’s toys, apple juice and chickens. Such stories are met with surprise and shock, despite the fact that arsenic compounds are ubiquitous in the environment. Arsenic is commonly associated with poison and this is because some forms of arsenic, such as the white “inheritance” powder, arsenic trioxide, are toxic to humans in very small doses. Arsenic can also form organometallic compounds (organoarsenicals) in the natural environment and it was once thought that methylation provided a detoxification pathway. This is no longer thought to be true but it is also known that arsenobetaine (CH₃As⁺CH₂COO^-), which is prevalent in marine animals, such as edible seafood, is virtually non-toxic. Therefore the determination of the distribution of arsenic compounds, or species, in a sample is very important.

While the analysis of marine samples, which contain naturally elevated concentrations of arsenic, is straightforward by conventional methods (greater than 90% of total arsenic can be identified), often less than 50% of arsenic in samples collected from the terrestrial environment can be characterized. This amount is “operationally defined” meaning that the extraction and analytical method used is usually limited with respect to how much and what species can be analyzed. We have found, however, that the complementary use of methods such as HPLC-ICPMS (which requires an initial extraction step) and X-ray Absorption Spectroscopy (XAS; which can be applied to an intact sample) provide greater insights into the arsenic compounds in biological samples than either technique by itself. 

This talk will examine what we know about the types of arsenicals that are found in the environment and discuss why various species are present. Examples will be given from both the terrestrial and marine environment, including XAS‘maps’ of the arsenic distribution in biological tissues. Our studies have shown that the source of the organoarsenicals in the terrestrial environment is either diet (including selective retention by the organism) or metabolism of inorganic arsenic forms. Finally, we will look at the question of arsenic in two common consumer products, apple juice and wine, and consider what risks the arsenic may, or may not, pose to the consumer.

Friday, March 16, 2012 at 3:00 p.m. in ICT 121

Department Contact:  Dr. Jurgen Gailer

jgailer@ucalgary.ca