Use of non-destructive biomarkers to measure effects of pesticide exposure in meadow voles (Microtus pennsylvanicus) living in golf course ecosystems of the OttawaGatineau region
Creators: name: Knopper, Loren D
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2004
Subjects: subject: Biology, Ecology.

description: Unlike the clear causal relationship between acute pesticide exposure and mortality in non-target wildlife, the association between sub-lethal pesticide exposure and chronic health problems (e.g., cancer, birth defects, endocrine disruption) are not as easily established. Studies that have reported relationships between pesticide exposure and chronic health issues are often surrounded by controversy and scientific debate. As a result of the uncertain relationship between pesticide exposure and human and wildlife health, and likely due to the direct alarm of their constituents, many municipal governments throughout Canada are implementing bylaws that regulate the use of pesticides. In some cases, pesticide use on public and private golf courses also falls under the newly created bylaws. One of the main arguments of those opposed to these restrictions is that there is a lack of scientific evidence linking pesticide exposure to poor human and environmental health. With municipalities planning pesticide control in order to protect human and environmental health, and with the controversial debate around pesticide exposure and the onset of health problems, it seemed timely to examine some of the potential effects of exposure to commonly used golf course pesticides. The purpose of this doctoral thesis was to perform a detailed review of the carcinogenic and genotoxic potential of the most common pesticides used on golf courses of the Ottawa/Gatineau region, focusing on epidemiological and in vivo and in vitro mammalian laboratory evidence, and to conduct a non-lethal biomonitoring study to provide scientifically based measures of some possible consequences of repeated pesticide exposure on non-target animals living in areas of regular pesticide use. Specifically, genetic (e.g., DNA strand breaks and chromosomal damage), developmental (e.g., skeletal birth defects and asymmetry) and organismal effects (e.g., changes in clinical haematology, body condition, blood parasite load) were assessed in meadow voles (Microtus pennsylvanicus) living in golf course ecosystems of the Ottawa/Gatineau region of Canada. In general, voles from golf courses did not appear to differ in their asymmetry, skeletal birth defects, blood parameters, parasite load, body condition or level of chromosomal damage when compared to voles from reference sites. However, voles from golf courses did appear to experience significantly greater DNA damage expressed as single or double strand breaks. The comet assay showed that two parameters of DNA damage (e.g., tail length and moment) significantly decreased in relation to days since last application of a pesticide, and to days since the last application of a specific fungicide (DaconilRTM ) containing a potentially genotoxic active ingredient (chlorothalonil). The slopes of these exponential curves were not significantly different than the half-life decay curve of chlorothalonil on vegetation (half-life data obtained from another study). Moreover, both parameters appeared to increase in a dose-dependent manner with the amount of the last application of Daconil RTM.