Research Overview

The research focus is the investigation and interpretation of calcium isotope abundances for understanding processes in calcium metabolism that can lead to diseases like osteoporosis and osteopenia. In the near term this work will investigate how changes in the metabolism of calcium can affect the distribution of calcium isotopes in living systems. In the long term, the knowledge acquired may extend into clinical practice and ultimately yield benefits to patients suffering from these diseases.

Currently, no non-invasive or inexpensive test is available to continuously monitor bone density or calcium levels in the body. However, there is evidence to show that measurement of calcium isotope ratios in blood and urine can be used as a biomarker for the diagnosis of osteoporosis. In addition to the blood, bone, and urine, one can investigate Ca isotopic compositions and concentrations in hair and nails. We propose that calcium isotope ratios in hair and nails might be used as a new biomarker for the diagnosis of osteoporosis.

Though often falsely treated as purely a “smoker’s disease”, radon exposure the second leading cause of lung cancer. Due to poor ventilation systems in modern homes, radon originating from the soil is able to reach high concentrations causing greater exposure for inhabitants. An accurate test for lifetime radon exposure in biological tissue is necessary to provide reliable data for non-smokers in lung cancer screenings. We propose that this can be done by quantifying the amount of ²¹⁰Pb in readily available biological tissues. This is because ²²²Rn decays to produce ²¹⁸Po which then decays to produce ²¹⁰Pb, which is known to build up in soft keratinizing tissue such as nails. Toenails are ideal target materials since they are disposable tissues and acquiring them is a simple and noninvasive process.

The goal of this project is to determine the most practical way to quantify the lead within the sample. Measurement of the lead isotopes are done by isotope dilution mass spectrometry (IDMS) so we may surpass the sensitivity of current methods. We aim for this method to be able to detect ²¹⁰Pb present on the order of 10-¹⁵ grams of the element. This method of determining lifetime radon exposure marks a fundamental change in thinking in the field, as existing methods for determining radon exposure are based on counting the individual decays of ²²²Rn. The success of this project will allow for results of high precision and accuracy to be produced simply, cheaply and quickly.

Copper and zinc play critical roles in biochemical and geochemical processes. Disruptions in the delicate balance among these elements in living systems are implicated in diseases such as Alzheimer’s, Parkinson’s, and cancer. Often these elements interact in cooperative or antagonistic fashion in biogeochemical processes. The challenge is to gain insights into the physical and chemical mechanisms affecting these elements in living systems and thus understand how these metals are processed in the geosphere and biosphere. Careful quantification of the redistribution of an element’s isotopes provides valuable insights into processes on an atomic scale. Our goal is to understand why changes in the isotopic composition of Cu and Zn occur and exploit this knowledge to understand the role of these elements in biogeochemical interactions. The objectives of the research program will be realized by (1) development and deployment of stable isotope abundance measurements to uncover the distribution and variability of isotopic abundances in biologically significant systems; (2) identification of critical receptors and interactions where changes in isotopic composition occur; and (3) understanding physical and chemical processes responsible for isotopic variations integrating both experimental and theoretical approaches.

Water is a significant medium for the movement of metals from the geosphere to the biosphere and an important area to study metal transport and incorporation processes. In northern Alberta, the extraction of hydrocarbons from oil sand deposits uses water from the Athabasca River as well as recycled water that has come into contact with oil sands, or so-called Oil Sands Produced Water (OSPW). A new technology is being explored whereby petroleum coke, a by-product of the extraction of crude oil from the oil sands, is used to treat OSPW and remove polyaromatic hydrocarbons from the water such that water can be returned to the river. However, the treatment also leads to an increase in pH and some heavy metals including vanadium and molybdenum in treated water. There are many natural sources of heavy metals to the environment such rock weathering, volcanic activity, or natural bitumen seeps like those found in the Athabasca. Therefore, it is vital to distinguish between the natural and anthropogenic inputs so that appropriate procedures can be put in place to minimize human impacts in the region. The ability of isotope abundance data to provide information on the source and history of the material allows this method of analysis to provide unique information.