DEAD HORSE CREEK Report, Morden, Feb. 2011
LWF attended a public presentation in Morden, Manitoba on February 26th, 2011 and this is what we learned is happening in our watershed…
DEAD HORSE CREEK PROJECT (DHCP)
Charles Wong, Mark Hanson, Jules Carlson, Bill Buhay Jennifer Low, Scott MacKenzie, Pascal Cardinal, Sarah Beattie, Jonathan Challis, Renae Bennett, Vince Palace, Kerry Wautier, Caitlin Dyck, Safiya Thiessen
Many Manitoba communities rely on sewage lagoons to passively treat their sewage. Each year, around June 15th (after fish spawning) community sewage lagoons discharge their effluent into the many tributaries in the Red River Basin. This massive effluent release wipes out living things downstream (DHCP discovered the existence of a dead zone in the Red River near Morris and St. Agathe).
The DHCP team led by Dr. Wong, initiated this study to learn more about the impacts of this practice on aquatic ecosystems, to promote community awareness, and to develop remediation techniques for sewage treatment using aquatic plants in constructed wetlands.
The first phase established baseline data by sampling nutrients, micro pollutants, GHGs, micro flora and fauna, establish point and non-point pollution sources, and mapping/profiling tributaries at different locations. Second phase involves raising awareness and continued monitoring. Phase three will see the implementation of solutions such as “treatment wetlands” and monitoring of community water stewardship.
Findings and recommendations for 2010 include
• GHGs methane and nitrous oxide spiked right after effluent release; at the Winkler site where cells were aerated, methane flat lined
• Ammonia (mg/L): huge spike above Environment Canada’s disposal recommendations of 1mg/L; rivaled USEPA (5mg/L), rapidly removed once released, but nothing much left alive in the water
• Phosphorus levels during discharge were well-above discharge requirement of 1mg/L; in the form of total reactive P which is readily taken up and contributes to blue-green blooms; nonpoint source contributions (farms, runoff)
• Nitrogen levels may exceed Mb Conservations proposed limit of 15 mg/L (they had analytical issues); wintering discharges; nitrate major contribution (suggests creek sediments are not contributing a great deal)
• Organic micro pollutants (pesticides, pharmaceuticals, personal care products) ubiquitous in wastewater, even in small communities; also present from farm communities. In DHC used active grab sample and passive sampling (POCIS device) for continuous measurement and analyzed for several dozen likely organic contaminants:
1. 2,4-D a systemic herbicide is found everywhere in DHC including upstream; it’s not the wastewater because it’s actually a higher concentration before lagoons are discharged
2. Atrazine a corn herbicide from ag land use and runoff
3. Carbamazepine is an anticonvulsant and mood stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder; 28 tonnes/yr prescribed in Canada; only found during discharge, so definitely coming from wastewater; lasts long enough in the aquatic system to get into Lake Winnipeg
Preliminary Recommendations:
• Further treatment of effluents may be necessary
• Stagger discharge to relieve the shock to the river
• Put effluent through a treatment wetland before being released
Upcoming work will be to determine how constructed wetlands can be best operated to remove nutrients and organics:
1. Lab-scale experiments, under controlled conditions, will determine
a. How native aquatic plants remove nutrients and organics
b. Give insight as to how to design pilot-scale and full-scale wetlands experiments
2. Biological Assessments to determine how nasty is the stuff that’s killing things, using
a. caged fish studies using fathead minnow
b. invertebrate surveys (sediment-living organisms, indicators of healthy aquatic ecosystem) to determine distribution and changes in populations
c. assess extent of antibiotic gene in microbial community (kills off beneficial bacteria leaving survivors that are resistant to antibiotics) and then wipe them out
3. Pilot-scale Experiments to determine what kinds of wetlands can we make to best rid water of contaminants before it enters the tributaries. Will use 23,000 L containers to simulate constructed wetlands and compare to existing wetlands