Factors influencing the sorption and mineralization of pesticides, antimicrobials and estrogens in soil.

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My established research program focuses on pesticides applied in Canadian crop production, and on antimicrobials and estrogens that are introduced to agricultural soils because of applications of livestock manures or human wastes. The pathways by which pesticides, antimicrobials and estrogens distribute and dissipate in the environment are relatively similar and, when transported to surface and ground waters, these compounds decrease the quality of Canadian water resources. The Canadian government uses pesticide fate models in assessing the risks that pesticides pose to water resources. In the calculations used by current models, the sorption of pesticides in soil is assumed to be constant over time. However, in reality, pesticide sorption in soil continues to increase over time (i.e., aged sorption) and so this information needs to be integrated into regulatory assessments. Over the next five years, for selected pesticides, this research will quantify the impact of soil-textures and soil-landscape variability on the values of aged sorption parameters that can then be used by the Canadian government as inputs in order to improve pesticide fate model calculations. Biochars are solid carbon-rich residues derived through the pyrolysis of biomass. It has been proposed that biochars can mitigate the movement of pesticides, antimicrobials and estrogens from agricultural soils to water, and also remove these contaminants during water and wastewater treatment. However, many questions remain and so, through a range of projects, including method development, this research will advance the knowledge of how biochars interact with pesticides, antimicrobials and estrogens in soil and water systems. Trainees will examine whether (and, if so, how) biochar amendments can impact the rate of microbial degradation of these organic chemicals, and also whether biochars can impact pesticide sorption over time. Such studies will take into consideration the possibility that the physicochemical characteristics of biochars in soil may change over time, and will investigate how these changes could impact sorption and microbial degradation processes. The research will provide opportunities for one postdoctoral fellow, two Ph.D., two M.Sc. and five B.Sc. students to receive comprehensive training in technical skills that are in high demand by potential employers within agricultural and environmental sectors. Their research findings will assist the Canadian government in improving the accuracy of the predicted pesticide transport from soil to water. Their work will also help to determine whether there are advantages to using biochar applications in Canadian crop production systems, and in water and wastewater treatment strategies. The research results will be published in international journals to impact the future work of scientists in a range of disciplines.