Kevin Murphy
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Fraser River Studies Lab
Biology 285
Fecal Coliform Testing

Introduction

The Fraser will receive a certain amount of fecal material naturally due to animal waste being deposited directly or by rainfall washing waste material into the river. However, in a natural setting, vegetation, which will stabilize top soil, holds water and acts as a filter as it slowly releases it back into the river. The vegetation will use the soluble organic waste moving with the water as it filters past root systems. Sand and soil particles will also gather solid waste particles as water flows through the soil. On our trip down the Fraser River we passed through many natural areas, but we also passed through many disturbed areas. Areas with large human populations being the most disturbed (with regards to top soil and ground vegetation). It is in these areas that one would expect to find evidence, in the form of e-coli, in the river water. Not necessarily due to the pumping of treated sewage into the river (as the sewage is chlorinated in the contact tank followed by the addition of sulfur dioxide to remove the chlorine) but due to the presence of storm drains and pavement, which does not allow for any natural filtration of waste, combined with a larger population of certain animals that due well in urban settings and the presence of house hold pets. This run-off will most likely contain an amount of waste over and above that of an undisturbed site. Population growth may also surpass the planned capacity of sewage treatment plants and they may not be able to keep up with the amount of sewage entering the plant.

It should be noted that common e-coli is not a harmful bacterium (there are some harmful strains, however, such as ‘hamburger disease’), and is present in human digestive tracts. Its presence in an area is a strong indicator that sewage, which will almost certainly contain pathogens, is being released with it. It is also a cheap and relatively easy substance to test for.

The federal government sets standards that must be met or beaten by the provincial government for e-coli counts. BC has set it’s own standard; according to the BC Safe Drinking Water Act, total allowable e-coli is zero. We collected Fraser River water samples above and below two populated areas’ sewage outflows. The first Quesnel, and second Hope. In doing so we wanted to discover if any raw sewage was entering the river. I suspected we would not detect any e-coli from the upstream test sites, but would get small amounts from downstream, depending on recent rainfall in the area.

Procedure

After rinsing out our sample jars three times with water from the test location, approximately five kilometers upstream from Quesnel we obtained five first station samples at 1:45 p.m. on July 4, 1997. This area had vegetative cover along and well back from the riparian zone but was a disturbed area and had a human population. Our five second station samples were taken approximately two kilometers down stream from the Quesnel sewage outflow at 4:30 p.m. the same day. This area also had riparian vegetative cover but was a disturbed area and was also downstream from an urban setting.

We also added to our experiment at approximately 8:00 p.m. the same evening by taking a sample of water from one of our drinking water storage containers. We did this because people were not following proper procedure and transferring water from this container into a second one with a pouring spout. They were dipping their water bottles directly into the container and touching the water with their hands.

Using a Millipore filtration apparatus, we poured 100 ml of sample water into the funnel. A .45 micron filter paper was used between the funnel and the and the suction portion of the apparatus (see diagram). This filter was then placed in a petris dish and a medium specific to the growth of e-coli colonies was added. The petris dish was then placed in an incubator (we used a styrofoam container for this, hoping to maintain a temperature conducive to e-coli growth, 45 degrees celcius).

We followed the same procedure in collecting samples from above and below Hope’s sewage outflow on July 13, 1997. Areas both above and below the outflow were in human disturbed areas, but there was vegetation located on the riparian zones.

It should be noted that in both our study sites the areas were without rainfall for at least a couple of days prior to our tests. This is important as rainfall drainage collects waste and washes it down storm sewers which can then go directly into the river or be diverted through treatment plants, which may push them past capacity, depending on the time of day.

Results

On July 6, 1997, our results for the first station tests (plus the drinking water) samples were observed. All river water samples turned up zero e-coli colonies per 100 ml sample. The drinking water sample resulted in nine e-coli colonies per 100 ml sample.

On July 18, 1997, our results for the second station tests again turned up zero e-coli colonies per 100 ml of sample water.

Discussion

Our results have shown that during test times, both Quesnel’s and Hope’s sewage outflows met both federal and provincial standards. I could not come to this conclusion, however, if we had not taken the samples of our drinking water. The reasoning behind this statement is that a possible flaw in our procedure was the use of a styrofoam box for an incubator to maintain a 45 degree celcius temperature. We did not measure the temperature in the Styrofoam box and could not be sure it was conducive to e-coli growth. The fact that our drinking water sample did grow nine e-coli colonies demonstrates that the temperature in the styrofoam box was in fact conducive to e-coli growth.

Unfortunately, we did not take a control sample of drinking water from a water barrel that had not been dipped into. Therefore, no conclusions can be drawn as to whether the e-coli contamination came from the dippers hands, or whether the source was contaminated. However, since the contamination was discovered, and the water bleached and then boiled before use and having no one fall ill after consumption, evidence strongly suggests the hands of the dippers (whom had at this point been five days into the raft trip) being the point of contamination.

Another factor involving Quesnel’s and Hope’s zero e-coli count is the lack of rain fall prior to our testing. The Fraser river’s mean flow is 3,972 cubic meters per second (Obee, 1993). This rate is well capable of moving any contamination far away from our test site. In order to properly evaluate these towns sewage outflows and storm drain runoff for sewage, the water sample would have to be taken during peak sewage treatment flows and during or immediately following rain fall.

Acknowledgments

To all those Fraser River Studies folks who dipped their hands and water bottles into the drinking water, they did in fact, unwittingly, create a control sample allowing us to conclude positively if our samples were capable of growing e-coli colonies. Thank-you.

Also to Dean for explaining the procedures to us.

Literature Cited

Obee, Bruce. “Hell-Bent on the Fraser. Exploring the middle reaches of BC’s
mightiest river.” Beautiful BC, May 1993, pp. 34.

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