Recent concerns of fate of arsenic in the soil that has leached from wood treated with chromated copper arsenate has prompted us to take on this project through the National Science Foundation GK-12 STEM Connections Program.One of the goals of this project is to investigate the various hypotheses concerning the fate of the arsenic in the soil. There are three possible options (and combinations of these):
(a) arsenic is converted by soil bacteria into methylated forms which are volatile,
(b) arsenic is washed out of the soil into surface and groundwater and
(c) arsenic reacts with inorganic species in the soil (particularly those containing iron oxides) to form inert mineral phases.
In order to get an accurate picture of whether soil and groundwater are being contaminated by these chemicals, it is necessary to obtain large numbers of samples (over an extended time-period) from several sites some of which feature pressure-treated timber structures and some of which are pristine (to allow background levels to be established). It is proposed that K-12 classes take responsibility for the identification, mapping and sampling of sites. The samples could be subjected to preliminary treatment at the schools. Drying, weighing and extraction with simple solvents, for example, could be performed in a high school laboratory. Some of the subsequent analyses could be performed by graduate students.
This project is currently running under PI Tyson’s direction with STEM fellows, Laurin Sievert and Lisa Provencher. Similar studies relating to the fate of the copper and chromium could be undertaken, and the presence of other arsenic-containing compounds (such as those used as herbicides and insecticides) could be examined. There are numerous other projects which require the development of suitable analytical chemistry procedures so that reliable information about chemical composition needed to evaluate various hypotheses may be provided. Other topics that might form the basis of projects in the schools include examining the question as to whether cigarette butts are a significant source of phosphate (and might pose a potential eutrophication hazard) or whether antimony from automobile brakes pose any health hazard. Participants will come to recognize the fundamental importance of measurement science in underpinning developments in diverse areas of science.