An Experiment to Determine the Level of Pollution in Sandy Creek

Categories: Water Quality

Intro Water quality in streams or creeks can be determined by examining the number of bioindicators. Bioindicators are species that populations are monitored to determine the health of the ecosystem itself. The health of streams and creeks is very important because most of the ecosystem relies on them for water, which is vital for life.

Many things can be harmful to streams and creeks. One of the main things is pesticides from farms or houses. Almost all farms and even some houses use pesticides in the United States.

A pesticide is a substance that is used to prevent or destroy pests that may affect crops (EPA). If not used carefully they could find their way into streams due to being carried by runoff when it rains. Other factors also go into determining the health of a creek, like the speed at which the water is moving downstream or the amount of direct heat from the sun the stream gets. If the water gets too warm the organisms in the creek would not be able to sustain life.

Pollutants from the surrounding area can also have a big impact on the health of the stream. For example road salt from bridges ever the streams can find its way into the streams when the snow melts in the stream. More visible from the roads are people just throwing their garbage out the window and also being carried into the stream when it rains.

The purpose of our experiment is to test one of the local streams in Brockport to determine its HBI value which tells us the health of the water.

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My hypothesis before we did the experiment was that even though there might be some pollutants from runoff into the creek, the creek would be relatively healthy because of the health of the surrounding area.

Methods On Friday 26 Septembefitsr 2014 at about nine in the morning we went to Sandy Creek, which is about ten minutes from the College of Brockport in New York. It was a warm fall day with little cloud cover in the sky. The creek had a house about a hundred yards from it that sat up on a hill. On the other side, about 300 yards away was what appeared to be a cornfield. The stream was a rocky stream and most of the rocks were limestone. There was also a natural dam upstream a bit that was visible from where we tested. To gather our information we used a net and wore boots so we could go into the water. We also used tweezers to closely observe what we got in the net. To gather the macroinvertebrates we did kick sampling, to do this we held the nets so the water was running down through them. Then we would kick the mud and rocks upstream from the net, which would stir up any macroinvertebrates and send them into the net because of the flow of the water.

After observing, counting, and recording the number of each species we calculated the health of the stream by dividing the tolerance-rating sum by the total number of organisms.

Doing the data collection we had to collect at least a hundred different macroinvertebrates, we managed to get 113. Table 1 shows visually what kind of macroinvertebrates we collected while we were at the creek. The Mayfly larvae were the most caught and more than likely the most common in the creek. By dividing the tolerance rating sum by the total number of organisms the HBI rating came out to 4.2478, this value fits into the “good health” category for creeks.

Discussion What our sampling found was very close to what I expected before we started testing and the data backs that up. Even though there might be some pollution being carried by runoff into the creek the overall health of the creek is still good. Our samples were only for a small part of the creek so in the future it might be a good idea to test different areas of the creek just in case the date varies in different parts.


  1. About Pesticides, Online. Environmental Protection Agency, Available at

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An Experiment to Determine the Level of Pollution in Sandy Creek. (2022, Jul 23). Retrieved from

An Experiment to Determine the Level of Pollution in Sandy Creek
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