Water working group

Group Lead: Dr. Corinne Ong, Ryerson University

Investigation of different on-farm nutrient management strategies on the fate of pathogens in agricultural watersheds in Ontario

Other researchers involved: Brent Dixon, Rebecca Guy, Rasha Maal-Bared, Pia Muchaal

Currently, livestock manure, biosolids, and non-agricultural source materials are applied to farmland in Ontario for nutrient management purposes. While composting reduces the concentration of nutrients and pathogens in these materials, it does not eliminate them. Data on potential microbial contamination of soil and surface water after compost application onto agricultural lands exists, but few studies have focused on the fate of emerging bacterial and viral pathogens and environmentally-hardy protozoans in composted deadstock, biosolids, and cracked bedrock aquifers. As such, the objective of this study is to compare the effects of different compost types on the fate of pathogenic microbial contaminants (bacterial, parasitic, and viral) and nutrients (nitrates, orthophosphates, and ammonia) in surface and groundwater resources in agricultural watersheds in Ontario, with a particular focus on the use of composted deadstock and biosolids. Our study thus has clear implications for the health, safety, and sustainability of rural communities and agricultural ecosystems.

Sewage treatment efficiency in urban, rural and First Nations communities

Significant numbers of human microbial pathogens are present in urban and rural sewage. Although most pathogens can be removed from sewage by various treatment processes, many survive treatment only to be discharged into the effluent and enter receiving waters. There are two types of pollution that need to be mitigated in order to protect public health: a) point-source pollution, which enters the environment at distinct locations through a direct route of discharge of treated or untreated sewage; and b) non-point pollution, which are generally diffuse and intermittent and may be attributable to the run-off from urban and agricultural areas, leakage from sewers and septic systems, and sewer overflows. This problem is exacerbated in agricultural and in remote northern communities; in the former due to excessive applications of animal manure and agricultural chemicals onto cropland and in the latter due to challenges in the management and operations of sewage treatment plants. In 2009, Aboriginal Affairs and Northern Development Canada (AANDC, formerly INAC) assessed the efficacy of 740 wastewater treatment facilities in First Nations communities and found that 60 were high risk and failed to meet the standards outlines in the Canadian Guidelines for Effluent Quality and Wastewater Treatment and Federal Establishments.

Pathogens pose a significant threat to human, animal and agricultural health therefore there is a need for rapid, reliable and sensitive detection tools that can be used for a broad spectrum of targeted microorganisms from mostly complex environmental matrices. Treatment of source water contaminated by Cryptosporidium and Giardia presents a particular challenge to water-quality managers due to: the ubiquity of protozoa in wastewater effluents, the widespread infection of domestic animals and wildlife, the resistance of protozoans (especially Cryptosporidium) to traditional disinfection methods, and the uncertain relationship between the presence of protozoans and faecal indicator bacteria typically used in water quality monitoring. Also, treatment efficiency for bacterial, viral and protozoan pathogens is compromised in circumstances where treatment plant capacity is challenged by growths in population size, or where treatment conditions are not optimal (e.g. temperatures and residence times are too low to completely remove pathogens). The objective of this work is to develop a new research team with a focus on waterborne microbial pathogens in the environment to improve our understanding of the short- and long-term impacts of current practices on ecosystems, and consequently on the health and wellbeing of Canadians.

Investigation of human health significance of environmental source Giardia cysts that are found in raw and treated drinking water

Project Lead: Peter Wallis

Giardia cysts are resistant to chlorination, especially at cold temperatures and pH above 7, therefore water treatment systems relying on chlorination alone leave consumers at risk. Many animal source Giardia isolates have no known potential to infect humans, however, so the risk to human health is usually unknown. The objective of this work is to use forensic molecular genotyping to expand the existing database of environmental isolates. Improvements to methodology for cyst recovery, PCR amplification and sequencing are needed to improve sample analysis time and respond to potential outbreak situations.