HMGA Water Project
  • Home
  • Project Overview
    • Project Description
    • Project Team
    • Collaborative Projects
    • FAQ
  • Publications
    • Blog
    • Factsheets
    • News Articles
  • Events
  • Gallery
  • Dedirting
  • Contact

Water-borne Pathogens and Food Safety

12/15/2014

1 Comment

 
Pathogens are micro-organisms which can cause harm to human health and the environment. Pathogens include viruses, bacteria (such as E. coli and Salmonella), and protozoan parasites (such as Cryptosporidium and Giardia). Water-borne pathogens survive, and some reproduce, in water. Common sources of pathogens to aquatic ecosystems include municipal wastewater effluents, agricultural wastes (mainly livestock and poultry fecal waste), and wildlife. Surface water has a higher contamination risk than groundwater as the contaminants from the source will generally run off into the surface water before it infiltrates to groundwater.

Water-borne pathogens can be very harmful to humans, and affect health through drinking water, and fruits and vegetables that come into contact with surface water through irrigation or washing. The effect of a pathogen on humans depends on the type of pathogen and the concentration. For example, a pathogenic strand of E. coli, O157:H7, can cause illness in humans with the ingestion of fewer than 10 cells. It is estimated that 90,000 illnesses and 90 deaths a year in Canada are a result of water-borne pathogen infections. High pathogen levels in an aquatic system can also disturb human recreational activities like swimming as well as posing a threat to animal health, aquaculture and aquatic systems biodiversity.
Picture
Figure 1: Water-borne pathogen potential pathways [Source: http://www.ijc.org/php/publications/html/12br/figures/biological2.jpg]
Water used for irrigation and washing is regulated to reduce the risk of pathogenic contamination of food and run off to the environment. The Canadian Guidelines for Water Quality in Agricultural Uses states that irrigation water must have less than 100 fecal coliforms/ E.coli or 1000 total coliforms in 100 ml of water; drinking water standards, which is applied to wash water, is stricter with 0 total coliforms allowed in 100 ml. Many water-borne pathogens will decrease in the environment if no additional contaminated source water is added with the length of survival depending on individual micro-organism.
Picture
Figure 2: The levels of coliforms used as indicators of contamination in water [Source: http://www.omafra.gov.on.ca/english/crops/facts/10-037.htm]
References
  • CanAgPlus. 2014. Appendices to CanadaGAP Food Safety Manuals. CanadaGAP Program. http://www.canadagap.ca/uploads/file/English/Manuals/Version%206.2%20Updates/Appendices/CanadaGAP%20Appendices%206.2%202014%20ENG.pdf
  • Edge, T., Byrne, J.M., Johnson, R., Robertson, W., & R. Stevenson. 2008. Waterborne Pathogens. In: Threats to Sources of Drinking Water and Aquatic Ecosystem Health in Canada. Environment Canada. Burlington, Ontario http://www.ec.gc.ca/inre-nwri/default.asp?lang=En&n=235D11EB-1&offset=2&toc=show#cur
  • OMAFRA. 2010. Factsheet- Improving On-Farm Food Safety Through Good Irrigation Practices. Order Number 10-037. Guelph, ON. http://www.omafra.gov.on.ca/english/crops/facts/10-037.htm
  • Public Health Agency of Canada. 2013. Food-borne and Water-borne Infections- Invisible Threats. In: The Chief Public Health Officer’s Report on the State of Public Health in Canada, 2013 Infectious Disease –The Never-ending Threat. Ottawa, ON http://www.ec.gc.ca/inre-nwri/default.asp?lang=En&n=235D11EB-1&offset=2&toc=show#cur
1 Comment

Nitrogen’s Impact on Air, Land, and Water

12/1/2014

0 Comments

 
Nitrogen is an essential nutrient for the survival and growth of most living organisms.  Nitrogen gas is a large constituent of the atmosphere, making up approximately 80% of the air, but this form is inaccessible by most plants. Certain bacteria in soils have the ability to ‘fix’ naturally-occurring nitrogen from the atmosphere, which converts it to a usable form for the plants, it can also be fixed by lightning or through an industrial process which makes nitrogen fertilizers. Nitrogen is generally the limiting nutrient in terrestrial ecosystems, and is applied to fields through use of fertilizers and manure. Once in the soil, the nitrogen will be used by the crops, leached down, or emitted into the atmosphere. In the soil, ammonium (NH4+) or ammonia (NH3) is broken down by bacteria through nitrification in which it is converted first to nitrite and then to nitrate. 
Picture
Figure 1: The Nitrogen Cycle [Source: http://fyi.uwex.edu/discoveryfarms/2010/10/fall-can-be-a-good-time-for-nutrient-application-with-awareness-of-conditions/]
Both nitrites (NO2-) and nitrates (NO3-) are highly soluble forms of nitrogen and thus are transported easily in water and do not attach to the soil. Nitrite is more toxic than nitrate but since the processes changing nitrite to nitrate happen quickly it is not generally found in large quantities. Though less toxic, high concentrations of nitrate in aquatic systems can have both acute and chronic lethal effects on amphibians as well as any species which prey on amphibians, such as fish. NH3 which has not been converted through nitrification can also have harmful effects on aquatic organisms. The major sources of NH3 in aquatic systems are wastewater and treatment plants. 
In both the Lake Simcoe Region (Figure 2) and Nottawasaga Valley (Figure 3) watersheds, the groundwater quality ranges from fair to excellent, with fair ratings due to chlorine amounts as opposed to NO2- + NO3- levels. This means that the Holland Marsh, an intensive agricultural area, contributes low amounts of NO2- + NO3-.
Picture
Figure 2: Groundwater Quality in the Lake Simcoe Watershed 2013 [Source: Lake Simcoe Region Conservation Authority, 2013]
Picture
Figure 3: Groundwater Quality in the Nottawasaga Valley Watershed 2013 [Source: Nottawasaga Valley Conservation Authority, 2013]
References
  • Lake Simcoe Region Conservation Authority. 2013. Lake Simcoe Watershed Report Card 2013. Newmarket, ON http://www.lsrca.on.ca/about/watershed_report_card.php
  • Nottawasaga Valley Conservation Authority. 2013. Nottawasaga Valley Watershed Report Card 2013. Utopia, ON http://www.nvca.on.ca/watershed-science/watershed-report-cards
  • Ontario Ministry of Agriculture and Rural Affairs. 2005. Factsheet - Environmental Impacts of Nitrogen Use in Agriculture. Order No. 05-073. Guelph, ON http://www.omafra.gov.on.ca/english/engineer/facts/05-073.htm#5
  • Rouse, J.D., Bishop, C.A., & J. Struger. 1999. Nitrogen Pollution: An Assessment of Its Threat to Amphibian Survival. Environ Health Perspect 107:799-803
  • Environment Canada. 2013. Ammonia Dissolved in Water. CAS (Chemical Abstract Service) registry number: 7664-41-7 https://www.ec.gc.ca/toxiques-toxics/Default.asp?lang=En&n=98E80CC6-0&xml=E9537B48-E09B-4FCF-8A56-F1F44B97FAE4
0 Comments

    Project Updates

    Find articles on project-related topics here

    Archives

    December 2016
    October 2016
    September 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014

    Topics

    All
    Aerators
    Coagulation & Flocculation
    Deionization
    Discharge Characterization
    Drum Filter
    Filter Bags
    General Information
    Hydrocyclone
    Lake Simcoe
    Lesson Learned
    Muck
    Nottawasaga Valley
    Pre Treatment
    Pre-Treatment
    Sampling
    Settling Ponds/Tanks
    South-Eastern Georgian Bay
    System Evaluation
    Treatment Technologies
    Ultrafiltration
    Washing Process
    Water Quality Parameters
    Watershed

    RSS Feed

    Article Titles

    Introduction to
      Watersheds

    Lake Simcoe Watershed
    Nottawasaga Valley
      Watershed
    South-Eastern Georgian
      Bay Watershed
    Water, Water,
      Everywhere?
    The Trouble with Muck:
      Size
    Lesson Learned: Bottom-
      up Aerator to Treat
      Washwater in Settling
      Tanks
    Phosphorus, the
      Environment, and
      Farming
    Nitrogen’s Impact on Air,
      Land, and Water
    Water-borne Pathogens
      and Food Safety
    Defining Dissolved
      Oxygen
    Filter Bags
      Demonstration Site
    Organic Matter
      Breakdown &
      Biochemical Oxygen
      Demand
    Dealing with Cloudy
      Water
    Hydrocyclone
      Demonstration Test
    What IS Muck?
    Demystifying Oxidation-
      Reduction Potential
    News Release
      "Technology
      Investigation: Filter
      Bags"
    Drum Filter
      Demonstration Site
    Decomposing With(out)
      Oxygen
    Flow monitoring
    Lesson Learned: Drum
      Filter Optimization
    Polders & the Holland
      Marsh
    Vegetable Washing
      Process
    ​Dry Soil Removal
    Ultrafiltration &
      Deionization
      Demonstration Site
    News Release
      "Technology
      Investigation:
      Ultrafiltration &
      Capacitive Deionization"
    Progressive Passive
      Filtration
    ​Dissolved Air Flotation
    Clarifying the Solid
      Removal Process
    Factsheet Reading Order
    News Release:
      "Technology
      Investigation:
      Coagulation &
      Flocculation"
    Self-Indexing Filter
    Monitoring Discharge
    ​  Flows
    Settling Soil
    Mass Loading
      Calculations
    Lesson Learned:
      Technology Selection
    Electrocoagulation
    Auto-Samplers
Powered by Create your own unique website with customizable templates.