RESULTS AND ANALYSIS
The levels of atrazine in the North Campus Pond were found to be two micrograms per litre. The acceptable level of atrazine is three micrograms per litre of surface water (United States Geological Survey, 1998).
Although atrazine has a low toxicity to mammals, birds, and fish at miniscule concentrations, many aquatic organisms are susceptible to levels less than 10 parts per million (Sassman et al., 1984). Atrazine also has a tendency to bioaccumulate (Sassman et al., 1984).
The levels of metolachlor in the pond are 16.4 micrograms per litre. According to the Provincial Water Quality Objectives, the acceptable limits of metolachlor are also three micrograms per litre of surface water (Canviro, 1998). Metolachlor degrades quickly, but high levels still justify cause for concern (USDA, 1993).
It is moderately toxic to both cold and warm water fish even though it completely degrades within two to twenty months (USDA, 1993). The concentration of Metolachlor in the North Campus Pond was considerably higher than the suggested limit.
A hand held net was used but the carp were to too quick for this method. A conventional fishing pole was utilized for our second attempt. The hook was baited with a doughball, then floated out into the pond with the aid of a bobber. The carp, however, proved uninterested with this technique. Lastly, an artificial worm body attached to a jig-head was cast several times into the pond. Again the carp were not interested with this technique either. A decision was made that exact population levels for the carp in the North Campus Pond were not needed and therefore not investigated further.
Carp continually stir the bottom of the pond during both mating and eating (Crossman, 1973). They are omnivorous, and feed by sucking up a mouthful of substrate ooze and detritus, and expelling it into the water, thus stirring up undesired particles (Crossman, 1973). This displaces sediment and makes the bottom unsuitable for vegetation growth and colonization (Crossman, 1973). The carp also eat amphibian eggs and tadpoles, consequently depleting frog and toad populations in the area (Crossman, 1973).
4.2.1 Fish Removal
The removal of the Carp population is desired to improve the water quality of the pond. Professor Duthie has expressed that a chemical toxicant called rotenone is likely to be applied to the pond to kill the Carp (Duthie, 1998). Rotenone is a chemical toxicant that is deadly to fish as it disrupts their process of cellular respiration (Murphy, 1996). The chemical was used widely for many years throughout the U.S and Canada in the 50s and 60s to control nuisance species so sport fishes could be restocked (Murphy, 1998). Professor Duthie has explained that in his opinion rotenone is the most effective way to remove the carp as all the fish will be killed and the toxicant will not persist in the environment as it has a half life of five days (Duthie, 1998). Duthie acknowledged that most invertebrates in the pond will die during the application, but he said that the frogs would likely live (Duthie,1998). Steven Cooke, however, contradicted this opinion and stated that some amphibians such as frogs would also be adversely affected (Steven Cooke, 1998). Moreover, turtles and metamorphosing amphibians which are especially vulnerable will also die (Murphy,1996,pg. 308).
The proper application of rotenone is very important as the toxicity of rotenone varies widely according to the environmental factors of the site (Murphy, 1996). "Rotenone is most toxic in warm water (>twenty degrees Celcius), acidic water, clear waters that have little aquatic vegetation"(Murphy, 1996, pg.308). Therefore, since our pond is very warm and has little vegetation, it is very important that the proper application of rotenone be highly specific to the exact conditions of that day, in order to prevent a total annihilation of all life.
Although rotenone does not persist in the environment, today it is not a highly accepted method to removed fish as its use is not allowed in five Canadian provinces (Murphy, 1996). Using toxicants such as rotenone to control fish populations will lead to bad public relations. (Murphy, 1996). Schools require a good public image to attract new students and maintain a good reputation in the community, which might be tarnished by the use of rotenone on campus.
It is recommended that rotenone not be used due to the effects it will have on the other species in the pond. In addition, we feel that it is not in the best interest of the Universitys public relations and reputation to use an out-dated toxic substance to kill fish. It is our recommendations that active fishing methods like beach seine nets be explored in order to control the population of the carp in the pond.
The invertebrates were catagorized into the Macroinvertebrate Taxa Group Chart. The crayfish was categorized into Group Two which is indicative of a broad range of water quality. The mayfly family are generally catagorized in Group 1, which is indicative of good water quality. However the small mayfly, found in the pond, is usually tolerant of more water pollution than its relatives in the same family (Knopf, 1997). The other invertebrates found were characteristic of small ponds and slow moving streams (Knopf, 1997). Overall the invertebrates indicate various tolerances of water pollution, more importantly, none were indicative of good water quality. The following chart lists the invertebrates found within the North Campus pond.
Figure 1.1 Common and Scientific names of the invertebrates found in North Campus pond.
|Common Name:||Scientific Name:|
|Large Whirligig Beetle||Gyrindae dineutus|
|Water Boatmen||Hemiptera Corixidae|
|Small Mayfly||Ephemeroptera baetis|
|Red Freshwater Mite||Limnochares americana|
|Six-Spotted Fishing Spider||Dolomedes triton|
|Kirby's Backswimmer||Notonectidae kirbyi|
The five most dominant species found in the survey area was Lance Leaved Goldenrod, Bittersweet Nightshade, Field Horse Tail, Reed Canary Grass and Smooth Brome Grass. Of the species identified, about 35% of them were alien, and included species such as Vipers Bugloss, Colts Foot, and Cow Vetch. Of the native species, 40% are typical of shoreline habitats similar to that surrounding the pond (i.e. damp soil, stream bank, and shore). These include the Lance Leaved Golden Rod, Field Horse Tail, and Reed Canary Grass and are considered to be representative of the area.
Table 2: Species List of Plants Identified Around the Pond Within 3m of Banks
|Common Name||Scientific Name||Classification||Habitat (Source: Newcombe)|
|Lance Leaved Goldenrod *||Solidago graminifolia||Native||Dry to damp areas; thickets, roadsides and streambanks|
|Bittersweet Nightshade||Solanum dulcamara||Alien||Moist Thickets|
|Field Horsetail *||Equisetum arvense||Native||Fields, woods, and waste places. Prefers damp soil|
|Reed Canary Grass *||Phalaris arundinacea||Native||Moist ground, stream banks, shorelines and marshes|
|Smoothe Brome Grass||Bromun inermis||Alien||Pastures|
|Red Clover||Trifolium pratense||Alien||Fields and Meadows|
|Fleabane||Erigeron philadelphicus||Native||Woods and fields|
|Vipers Bugloss||Echium vulgare||Alien||Roadsides and waste-places|
|Colts Foot||Tussilago farfare||Alien||Streambanks, roadsides, and waste places|
|Wild Bergamot||Monarda fistulosa||Native||Dry thickets and clearings|
|Riverbank Grape *||Vitis riparia||Native||Riverbanks|
|Cow Vetch||Vicia cracca||Alien||Fields and roadsides|
|Red Osier Dogwood *||Cornus stolonifera||Native||Wet places and shores|
|Hedge Bindweed||Convolvulus sepium||Native||Moist thickets and roadsides|
|Indian Hemp *||Apocynum cannabinum||Native||Shores and thickets|
|Blue Verbane||Verbena hastatta||Native||Thickets and roadsides|
|Black Willow *||Salix nigra||Native||Stream banks, pastures, forests, swamps and floodplains|
* Refers to plant species which are native to the area and considered desirable because
they are native and have similar habitats to what is present around the pond.
Note: Species are listed in descending order of relative dominance, as was estimated based on casual observations of population size.
4.5 Bank Erosion
Since the construction of the pond, the banks have been left to erode and deposit sediment in the pond. Because of their steepness no vegetation inhabitation has occurred. Also, the erosion of the banks, especially during rain storms, is the suspected cause of the high turbidity levels in the pond (refer to the Turbidity Section of Results and Analysis for specific levels), (Mitchell & Stapp).
Rill erosion and interil erosion both contribute to water erosion which is the main erosive process causing high turbidity levels after rain falls. Rill erosion is " the detachment of soil by hydraulic shear stress in concentrated confined flow " (Agassi, pg.267, 1996). Rill erosion causes shallow channels or troughs to form causing water flow with great erosive power (Leet, 1973). Interill erosoion is " the detachment and transport by raindrop impact and shallow overland flow "(Agassi, pg. 267, 1996). In order to limit water erosion on the banks it is necessary to prevent factors that contribute to soil erosion from occurring such as soil detachment and runoff volume and velocity (Agassi, 1996).
To reduce runoff velocity we recommend that the slope of the banks be altered to a more gradually gradient decreasing the velocity of water runoff. Another reason for reducing the slope of the banks is so that they can be easily inhabited by vegetation. This will decrease soil detachment as the plants vegetative cover will protect the soil from raindrop impact. The roots of the plants will secure soil also decreasing the amount of soil detachment.
4.6 Water Quality Index
The North Campus pond was sampled and tested for its water quality. The Water Quality Index of Mitchell and Stapp's Field Manual for Water Quality Monitoring was used (Mitchell and Stapp, 1993). This index produces a value that indicates the overall water quality of a section of a river system or a small water body. The index requires the following specific tests in order to calculate the appropriate values. For each site we tested for pH, turbidity, nitrates, phosphorous, temperature, dissolved oxygen (D.O.), biological oxygen demand (BOD), chloride, and fecal coliforms. The levels of these parameters are needed to calculate the Water Quality Index. Each level of the individual parameter is also valued as an indicator of possible inputs and help to identify the constitution of the pond.
The pond was sampled on two separate days. The first sampling day was right after a storm had hit the Waterloo region. This caused an influx in the water table, and we had speculated it would skew our results. This prompted us to take a second sample collection at a time when the water table was at its original level when we first observed the pond. We also decided to collect a sample from the drain, to test for possible inputs from the farmer's field. The following displays our results and analysis for each of the samples taken.
4.6.1 First Sample Collection
Date: June 17th, 1998
Weather: cloudy, with sunny periods
Sample Site: Site #1, within the pond
Site Description: On June the 16th, the Waterloo region had a major rainfall. The water table at the pond was raised considerably, flowing over the smallest of the four banks. The steepest and tallest banks were bare of vegetation, and erosion was evident. The various impacts this had on the pond are mentioned in each of the parameters descriptions.
Data Chart for Water Analysis of Site #1 (June 17th):
4.6.2 Second Sample Collection:
Date: June 29th, 1998
Weather: Sunny periods with some clouds, no previous or present rain fall for at least 5 days prior to the first sample collection.
Sample Site: Site #1: within the pond, same as previous sample collection on June 17th
Site #2: within the drain that empties into the pond from the farmer's field (refer to Figure ).
Site Description: The pond had returned to the original state we informally observed on June 12th. The water table was at least one meter below the top of the shortest bank. All banks were visibly bare of vegetation, and heavily eroded.
Data Chart for Water Analysis for Site #1 (June 29th) and Site #2 (Drain in farmers field):
The above values are compared to the Canadian Water Quality Guidelines in terms of recreation, and aquatic life standards (Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers, 1979). The following parameters are mentioned since they either exceed, or are close to the extremes of that standard. The values are then inputted into the calculation to determine the Water Quality Index, set out by Mitchell and Stapps Field Manual for Water Quality Monitoring (Mitchell and Stapp,1993).
4.7 Canadian Water Quality Standards:
According to the Canadian Recreational Water Quality Guidelines, the turbidity of a body of water should not be increased by more than 5 NTU naturally when turbidity is low (Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers, 1979). The standard low level of turbidity is <50 NTU. When analyzing the data collected in the charts above, the turbidity calculated is well below the recommended lower level of 50 NTU at sites #1 (from June 29th), and site #2. On June 17th, however, site #1 had its turbidity increased to 76 NTU. This influx exceeds the natural standard increase of 5 NTU, and is well above the standard of 50 NTU. High levels of turbidity can be attributed to heavy rain falls, and continuous bank erosion (Mitchell and Stapp, 1993). These levels can cause stress on aquatic life, and anyone using the pond for recreation. Suspended particles can clog fish gills, reduce a plants growth rate (inhibits photosynthesis), decrease resistance to disease, prevent egg and larval development, as well as irritate eyes of any pets going in the pond (Mitchell and Stapp, 1993).
Click here for turbidity chart
The water quality standards for nitrates according to the Canadian Water Quality Standards, is 45mg/L (Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers, 1979). On June 17th at site #1 the nitrate levels were tested at an alarming level of 70.4 mg/L. Several days later on June 29th, this diluted to 50.6 mg/L, slightly above the required limit. The drain, however, was at a lower level of 29.9 mg/L. This suggests that there are nitrates draining in from the farmer's field, collecting into the pond. The excretion of feces by the geese population (observed by their tracks in the pond), could also contribute to the levels within the pond. High nitrate levels cause eutrophication of surface water bodies, promoting more plant growth and decay (Mitchell and Stapp, 1993). This in turn increases biochemical oxygen demand, thereby threatening to limit organism diversity, recreational opportunities, and property values (Mitchell and Stapp, 1993).
Click here for nitrates chart
4.7.3 Fecal Coliform Count
Standards for fecal coliforms under recreation are set for swimming activities. Although there has been no reported swimming by people, Dana Couture mentioned in her Senior Honours Thesis, that dogs frequently swim in the pond (Couture, 1993). For swimming, fecal coliform counts should not exceed more than 200 coliforms/100mL. The fecal count for the pond at site #1 (June 29th) was at 4000 coliforms/mL. The count at site #1 (June 29th) was at 4900coliforms/100mL, which is clearly unacceptable. It is speculated that such an increase occurred due to runoff into the pond during the storm. Feces excreted by geese at the edge of the pond, were probably washed into the pond after the heavy rainfall, contributing to the high levels of coliforms. Various dogs swimming in the pond could account for high coliform levels. The fecal count tested on the water from the drain was 2000 coliforms/100mL. This collects into the pond, also contributing to its high levels of coliforms. This may suggest the presence of pathogens, which could harm pets swimming in the pond (Mitchell and Stapp, 1993).
Click here for fecal coliforms chart
4.7.4 Dissolved Oxygen
The standards developed for dissolved oxygen is directly related to the organisms present in the body of water (Mitchell and Stapp, 1993). There are different standards for cold water, and warm water habitats. Cold water habitat usually refers to moving streams with lots of shade cover (Mitchell and Stapp, 1993). Warm water habitat standards are usually more relevant to the North Campus pond, since it is a small body of water with little shade cover. Organisms at different stages in their lives require different levels of oxygen (Mitchell and Stapp, 1993). For warm water habitats, organisms in their early stages require a minimum of 6 mg/L of dissolved oxygen for survival (Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers, 1979). For organisms in other stages (possibly adult), they require a minimum of 5mg/L of dissolved oxygen (Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers, 1979). For site #1 (June 17th), the dissolved oxygen content was only 6.5 mg/L. This is low, compared to June 29th's sample of site #1 of 10.5 mg/L. Although both within the acceptable range, the low level of dissolved oxygen may have been caused by high organic matter within the pond, which was deposited by heavy runoff. This will cause organisms within the pond to break down the organic matter, using more oxygen in the process. Depletion of oxygen in the water will cause a major shift in the aquatic organisms found in the water body. Organisms such as stonefly nyphs, mayfly nymphs, and caddisfly larvae, which are indicators of good water quality, will be replaced by more pollution-tolerant organisms such as worms and fly larvae (Mitchell and Stapp, 1993).
Click here for dissolved oxygen results
The Canadian Water Quality Standards for chloride is set at 250 mg/L (Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers, 1979). This level is set to prevent any possible contamination and damage to organisms within a water body. The chloride levels at both sites on all three occasions were at 240 mg/L. Although this level is within the range, it is near the upper limit, suggesting that the chloride levels may reach undesirable levels. These levels may be attributed by the fecal matter (trace amounts are found in feces) and runoff of fertilizers from the farmer's field. Therefore the geese activity as well as the drain from the farmer's field could account for the levels of chloride within the pond.
Click here for chloride results
4.7.6 Results of the Water Quality Index:
The water quality index provides an indication of overall water quality through the integration of results from the individual water quality tests. The calculations were made according to the Field Manual for Water Quality Monitoring by Mitchell and Stapp (Mitchell and Stapp,1993). This involved taking the results from various parameter tests (i.e. oxygen saturation %) and arriving at a Q-value determined from one of the graphs for different parameters in the Field Manual (Mitchell and Stapp, 1993). The Q-value for the specific parameter was then multiplied by the weighted score for the specific parameter. The weighted score for each parameter was relative to the importance that parameter has in influencing water quality. The standards are shown in figure 6 below. The results obtained from the index gave a score of 62.6 for the water in the pond on June 19, which indicates good water quality. The water sample taken from the pond on June 29 produced a score of 66.9, which indicates medium water quality. On the same day, the water quality measured in the drain was 81.3, an indication of good water quality.
These results indicate that the water entering the pond through the drain was of better quality than the water in the pond on the days when sampling took place. However, it should be noted that the water sample taken from the drain was not taken on a day when there was any indication that run-off from the field occurred. The fields were dry and it had not rained in approximately one week. However, the pond would accumulate any contaminants contained in the runoff as the pond acts as a holding tank where the runoff collects and the contaminants accumulate over time. For that reason, it is expected that the water quality in the pond would be poorer than that in the drain. In addition, the drain contains no carp, which stir up sediment.
Click here for Water Quality Index Chart
Figure 6: Water Quality Index
|Water Quality Index|
|0-25 - Very Bad|
|25-50 - Bad|
|50-70 - Medium|
|70-90 - Good|
|90-100 - Excellent|
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