A. Sample sites
Choose 2 sampling sites, one upstream from the treatment area serving as the control and the other immediately downstream of the treatment area. Sampling in these locations should provide an indication of the maximum concentrations of chemicals due to fertilizer application. More sites should be selected if the treatment area covers a large area.
Sample sites should be located accurately. Only if the same location is consistently sampled can temporal changes in water quality be interpreted with confidence. Use accurately written station location descriptions, mark the sites in the field with flagging, and locate them on maps.
B. Sampling procedures
Use clean bottles and obtain water samples as close to mid-stream and mid-depth as practically possible. If sampling in a fish stream, take the water temperature at the sampling location. Temperature is necessary to assess ammonia levels. Label the bottles with the date, site location, and water temperature (if necessary).
Samples must be shipped on the day of collection in a cooler packed with ice, in order to maintain a sample temperature of approximately 4°C. The samples must be received by the laboratory within 72 hours of collection.
C. Sample frequency
Pre-application monitoring should be conducted for two weeks. Obtain three samples, twice per week at both control and treatment area sites. Obtain results back from the laboratory in a timely manner to enable changes to be made in the planned treatments if the analysis shows high levels of natural nitrogen or phosphorus.
Post-application monitoring should be conducted immediately following fertilizer application and then twice per week for three weeks. Also, if a storm event occurs during the three weeks post-treatment period, obtain water samples within 24 hours of the event. This will provide an indication on increased nutrient inputs through direct application to streams or through accidental spills.
Collect at least one sample approximately three months after fertilizer application, to document water quality returning to background levels. In the interior of British Columbia, at least one sample should also be collected immediately after spring floods.
D. Laboratory analysis
For both community watersheds and fish-sensitive streams, total dissolved phosphorus should be analyzed if phosphorus was present in the fertilizer mix. Samples must be shipped on the day of collection, and results received back from the laboratory as quickly as possible, preferably within 3 days.
Pre- and post-monitoring samples should be analyzed for pH, total nitrogen, total ammonia, and nitrate-N.
Pre- and post-monitoring samples should be analzed for pH, total ammonia and nitrite-N.
E. Analysis of concentrations
Post-treatment monitoring results exceeding levels specified in this guidebook should be reported promptly to the Ministry of Health; the water purveyor; Ministry of Environment, Lands and Parks; and the district silviculture resource officer, Ministry of Forests. These results should then be used to guide future applications.
Pre-treatment results that exceed the following thresholds for ammonia or nitrite-N are not recommended areas for aerial fertilization. Post-treatment results that exceed the threshold levels should be reported to the district silviculture resource officer, Ministry of Forests, and the Department of Fisheries and Oceans (DFO).
Nitrite-N should not exceed 0.06 milligrams/litre.
Recommended maximum levels for total ammonia (NH3) (from CCREM, 1987)
The application of phosphorus-based fertilizer should not result in detectable elevations of total phosphorus over background stream concentrations when appropriate streamside buffer zones are used. Detectable elevations should be reported to the district silviculture resource officer, the regional environmental section head for the MoELP, and the DFO.
F. Water Quality Branch, Ministry of Environment, Lands and Parks
The Environmental Protection Department of the Ministry of Environment, Lands and Parks operates a water quality program, and can be contacted for assistance with water quality monitoring in community watersheds. For information, contact:
Water Quality Branch
Environmental Protection Department
Ministry of Environment, Lands and Parks
765 Broughton Street
Victoria, B.C., V8V 1X4