What is Turbidity

What is Turbidity?

I have always been interested in my local environment, but it water that captivated me. Water has intrigued me since I was a small child wading in murky streams and ponds, hunting for creatures. As I grew older, I was able to appreciate the water for something more than the organisms it harbored, but for its place in the ecosytem. I began asking myself questions concerning organisms and their environment. I became interested in turbidity.

The purpose of this experiment was to find the relationship between a water’s origin or condition and its turbidity level, which was measured in JTU (Jackson Turbidity Units). It was hypothesized that if the water sample had a high acid concentration, then the water would be less turbid because fewer organisms would be able to survive in such conditions. To briefly summarize, five water types were collected: tap, melted snow, pond, stream, and shaken tap. (One tap water sample remained in its original state, while the other was vigorously shaken for one minute). The samples were then analyzed using the Logger Pro turbidity sensor and a laptop computer. The mean for pond water was 132.81 JTU, 128.67 JTU for the shaken tap water,134.13 JTU for the melted snow,138.22 JTU for the stream, and 136.18 JTU for the tap. Larger numbers indicate more turbid water. The range of the readings was 14.55 JTU, which was between the stream water (upper extreme) and the shaken tap water (lower extreme). The readings were abnormally high, which was most likely due to the amount of precipitation or technicalities experienced with the equipment. The hypothesis was therefore not supported.

The purpose of this experiment was to find the effect of water type on turbidity. (Water type refers to the water’s origin or condition). This topic was chosen to test Virginia’s water quality and potability, as well as to explore the connections between biology, geology, and ecology.

Turbidity is the concentration of suspended organic or inorganic particles in a given water sample that prevent light from passing through (Random House College Dictionary: “turbidity”). (Alternative terms are “poor transparency”, “murky”, “contrast reduction “, “hazy”, “poor clarity”, and “lateral luminosity”). Factors that affect turbidity are the particle size, particle shape, refractive index and the wavelength of light . Being aware of the turbidity levels in local streams can assist residents when installing dishwashers and washing machines, monitoring the water quality, and when building and maintaining pools and spas (Turbidity).

There are numerous particles that thrive in water. Some examples of inorganic particles that may be in the samples are barium, copper, fluoride, nitrate, lead, quartz, feldspar, iron, silica, carbonates, aluminum. Algae, protozoans, and insect larvae are just a few of the myriad organic particles that may populate bodies of water (Turbidity). These particles are responsible for the water’s appearance, as well as transparency. For instance, sunlight is able to penetrate relatively clear ocean water 262 feet and less than 164 feet in hazy ocean water (Bobick and Balaban, 90).

The prominent contributors to turbid waters are phytoplankton. (Phytoplankton are microscopic organisms that conduct photosynthesis to obtain food). However, shoreline erosion, channelization, large schools of bottom-feeding fish occupying an area (carp, for example), floods, constant rainfall,bubbles, and pollution can increase turbidity, also (Turbidity).

However, human interaction plays a major role in turbidity, too. Humans depend on water for consumption, recreation, cleaning, irrigation, agriculture, and hydroelectric power. Soil erosion from croplands and construction sites, debris from commercial and residential activities, run-off from pools and sewage, logging, mining, (Turbidity), and pesticides used in farming and lawn care can cause water to be murkier (weta.org). Pets swimming in the water can stir up the contents of stream beds and leave parasites, which cause the turbidity levels to escalate (Turbidity).

Additionally, drinking water with a high turbidity level may be hazardous to one’s health because some of the particles creating a cloudy semblance may include bacteria, viruses, and protozoans, which can spread waterborne maladies (Turbidity). One example of harmful microbial life in streams are amebas (Dorling Kindersley Science Encyclopedia, 314).

Furthermore, acid rain depletes bodies of water of aquatic plants and animals, which decreases turbidity levels. Sensitive creatures disappear when pH levels fall to six. Macrophytes are pH- sensitive microorganisms that thrive in streams, ponds, lakes, and rivers. If the macrophyte population decreases, many animals will be left with no food source because they occupy a major link of the local food chain (Turbidity) Of course, bodies of water have natural acidity, but the organisms have adapted to it through evolution (Turbidity).

Finally, excess particle matter can reduce the depth of bays and lakes through erosion. The particles from layers and as a result, the body of water becomes shallow. This endangers animal habitat because branches can be crushed and may collapse on breeding grounds; rock shelters can be filled with soil so that animals are not able to live in the crevices; insect larvae are delicate and the weight of the sediments produced by erosion can easily kill them. Silt can also impair fish’s ability to breathe by damaging their gills (Turbidity).

The hypothesis was that if the water sample was derived from an area with a high acid concentration, then it would be more turbid because fewer organisms would be able to survive in such conditions. The independent variable was the type of water. The levels of the independent variable were pond water, stream water, melted snow, tap water, and shaken tap water. The dependent variable was turbidity and was measured in JTU (Jackson Turbidity Units). The constants included air temperature, water temperature, air pressure, and light exposure. The control for this experiment was information from a reference source, which stated that the tap waster should be the least turbid.

The following materials were gathered: five juice bottles of equivalent size (capacity did not matter, as long as all of the bottles were identical), one bottle of food coloring, five beakers, one roll of masking tape, one permanent marker, one laptop computer, one floppy disk, and one Logger Pro turbidity measuring kit. Each juice bottle was then labeled A, B, C, D, or E with the masking tape and permanent marker. Water was then derived from a local stream and poured into bottle A. Water from the tap was put in bottle B and food coloring was added. Then, snow collected from outside was placed in bottle C and was shaken to quicken the melting process. Bottle D was filled with tap water and bottle E with pond water. Then, the five beakers were labeled A, B, C, D, or E with the masking tape and permanent marker. Bottle A water was poured into beaker A, bottle D water into beaker D, and bottle E water into beaker E. Bottle B and bottle C water remained in their respective bottles. The laptop computer was then plugged in to the outlet in the wall and attached to the turbidity sensor. An empty tube was placed in the turbidity sensor and was calibrated, followed by the tube filled with water included in the kit. Water from beaker A was analyzed as described in the instructions enclosed in the kit. The results were saved to the floppy disk. The water in bottle B was shaken vigorously for one minute so that bubbles would form and was poured into beaker B. Water B was analyzed exactly as water A had been. Bottle C was placed over the heating system if it had not melted. If it had, then it was analyzed in the same manner as water A. Waters D and E were analyzed in the same fashion. Each water was analyzed a total of ten times.

The turbidity for stream water was 138.22 JTU, 128.67 JTU for shaken tap water, 134.13 JTU for the melted snow, 136.18 JTU for the tap water, and 132.81 JTU for the pond water. The greatest difference in JTU measurements was between the stream water and the shaken tap water. The range was 14.55. The hypothesis that if the water sample had a high acid concentration, then the water would be less turbid because fewer organisms would be able to survive in such conditions was not supported by the data.

The title of this experiment was the effect of water type on turbidity. The purpose of was to find the relationship between a water sample’s origin or condition on its turbidity level measured in JTU (Jackson Turbidity Units). The averages for stream water, shaken tap water, melted snow, tap water, and pond water were as follows, respectively: 138.22 JTU, 128.67 JTU,134.13 JTU,136.18 JTU, and 132.81 JTU. The range of the data was 14.55 JTU. It was hypothesized that if the water sample had a high acid concentration, then the water would be less turbid because fewer organisms would be able to survive in such conditions. The results did not support the hypothesis because due to previous experimentation, it was discovered that despite the fact that the stream, pond, and snow had higher pH levels than the shaken tap and tap water, their readings were within 15 units of each other, which did not accurately display the significant difference that should have occurred. In similar experiments, the results revealed that the pond and stream water contained larger amounts of inorganic and organic particles than the tap water. The other researchers’ results do not support the results of this experiment because the readings were lower in theirs. Perhaps the immense precipitation caused the contents of the stream and pond to be distributed throughout the bodies of water, leading to high readings. The tap water probably was highly concentrated with particles because the precipitation caused the particles in the local reservoir to be distributed throughout the pipe systems in Arlington county or simply because the pipe system connected to the sink that the samples were obtained from must be replaced. To produce results more correctly conveying the ascending order of turbidity levels in water types in future experiments, the water samples should be collected during a day closely representing average precipitation levels in the area. As an improvement to the experiment, the water samples should not be exposed to varied air pressure, light, or temperature changes because this could kill any living organisms in the sample, thus causing a lower turbidity level to be read by the turbidity sensor.


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