Introduction Turbidity is the measurement (in NTU* ) of suspended matter such as clay, silt, organic and inorganic matter, plankton, and other microscopic organisms in water. An average person can begin to see turbidity levels starting at around 5 NTU. Lakes that are considered relatively clear in the United States can have a turbidity up to 25 NTU. Human activities that disturb the land can also cause high levels of turbidity in water by producing high sediment levels that enter the water through storm water runoff. *Nephelometric Turbidity Units (NTU)
Introduction Coliform bacteria are rod-shaped, non-spore forming bacteria. They can be found in aquatic, soil, or vegetative environments and are present in large numbers in feces of warm-blooded animals They are not normally causes of serious illness, however, their presence indicates whether or not pathogenic organisms are present. They are easy to culture
Introduction Some genera of coliform bacteria include: Citobacter Enterobacter Hafnia Klebsiella Serratia Fecal coliform Escherchia (E. Coli)
Introduction It is known that high turbidity in water can be correlated with unsafe drinking water, the higher the turbidity level, the higher the risk that people may develop gastrointestinal diseases. Experiments have shown that water with high turbidity, contaminated with feces, and other matter containing the hepatitis virus, caused illness Chlorinated water that was coagulated and filtered to remove the turbidity produced no illness
Introduction Measuring the number of coliforms helped scientists determine the relationship between turbidity and chlorine disinfection low numbers of coliform were found in waters with low turbidity and high numbers of coliform were found in waters with high turbidity
Methods and Materials First sample of data collection was from the water from Duck Pond located near Hillcrest Hall. Second sample was from the Garden Pond located near the Virginia Tech Hahn Horticulture Garden. Both the samples provided well enough data for turbidity test and dissolved oxygen content. A comparison of turbidity in 2 different ponds was easy to obtain based on the appearance of water – Cloudiness. We visited the duck pond and garden pond once and it didn’t take more than 30 minutes at each pond for data collection.
Methods and Materials Both qualitative and quantitative data will be collected. Quantitative: Measure of turbidity, measure of dissolved oxygen content and measure the number of colonies. Qualitative: Size, shape and color of the colonies.
Methods and Materials Dissolved Oxygen Test KitTurbidity Tubes
Methods and Materials Water turbidity was tested using a turbidity tube. Turbidity tube can measure turbidity ranging from 5 NTU to 250 NTU. The Turbidity tube condenses water in a graded tube which allows determination of turbidity based on a contrast disk in its bottom. We filled the graded tube with water and let the water come out of the extended tube located in the bottom. Looking through the tube, turbidity was measured when the water level reached the black line on the meter stick attached to the turbidity tube.
Methods and Materials Dissolved oxygen content was measured using a dissolved oxygen testing kit. The kit included: Water Sampling Bottle, Titrator, Sodium Thiosulfate, Sulfuric Acid, Alkaline Potassium Iodide Azide and Manganous Sulfate Solution. Dissolved oxygen can be measuredin units of ppm – parts per million.
Methods and Materials Fill the water sample bottle with water and add 8 drops of both Alkaline Potassium Iodide Azide and Manganous Sulfate Solution. Mix well and let the solution settle then add 8 drops of Sulfuric Acid. The solution turned bright yellow by now. Use the titrator and obtain 20 mL of Sodium Thiosulfate. Dispense the Sodium Thiosulfate solution into the water sample bottle till the solution turns clear. The point when the solution turns clear, dissolved oxygen can be measured.
Methods and Materials Water samples for each pond were obtained in specimen cups labeled Specimen D and Specimen G. 2 trials were done for each sample of pond water. 2 petri dishes were used for each sample of water for the micro organisms to grow. Microorganisms were grown in a total of 4 petri dishes and were studied after 48 hours for colonies.
Collected DataSample Dissolved Turbidity Total E. coli Total Total Oxygen (NTU) Colonies noncoliform Coliform (ppm) (per 100 colonies (per Colonies mL) 100 mL) (per 100 mL)Duck Pond 3.5 19 67 2033 6267ADuck Pond 3.5 19 67 2200 6567BHahn 6.4 27 100 4767 5400Garden AHahn 6.4 40 300 5900 5667Garden B
Number of Colonies200180160140120 E. Coli Colonies100 Noncoliform Colonies 80 60 Coliform Colonies 40 Turbidity 20 0 Duck Duck Hahn Hahn Pond A Pond B Garden A Garden B
Duck Pond CultureHahn Garden Culture
Statistical Test Correlation between E. coli & Turbidity: r2 = .0148 Noncoliforms & Turbidity: r2 = .4072 Coliforms & Turbidity: r2 = .7875 Amount of coliform and noncoliforms in water does correlate with the turbidity “The turbidity of a culture is dependent upon the shape and internal light-absorbing components of the microorganism and therefore turbidity readings are species-specific and cannot be compared between different microbes or even between different strains of the same species.” (Microbiology Laboratories)
Results There is more coliform present in the duck pond because there are more animals (ducks, squirrels, etc.) present. Coliform is found in animals digestive tract and are derived from their fecal matter (APEC) A presence of E. Coli shows a higher degree of fecal pollution and the possible presence of pathogens in the water (APEC).
Results The Hahn Garden pond had more E. Coli colonies than the Duck Pond. This higher amount of E. Coli results from the amount of fish that were in the Hahn Garden pond. The Duck Pond had no fish in it and the Hahn pond was filled with big coy fish and many other species of fish. Its presence of fish describes why the E. Coli colonies would be at a higher presence in the Hahn pond.
Results High levels of non-coliform colonies indicates a reduction in water quality (NH Department of Environmental Sciences). The Hahn pond had a significantly higher amount of non- coliform colonies then the Duck Pond. Our experiment reinforces the correlation that as turbidity increases water quality decreases. This can be seen in the number of non-coliform colonies in each sample of water. The Hahn pond had higher so therefore correlates with a higher number of non-coliform colonies.
Results Based on our results from this experiment it is safe to say that our hypothesis was correct. The amount of turbidity is correlated to the amount of microorganisms in water. If a body of water is more turbid than it was more microorganisms. The Hahn Garden pond was more turbid then the Duck Pond and therefore had more microorganisms.
Results Based off the types of microorganisms each pond had it is also safe to say that having more microorganisms results in a lower quality of water. Even though the Hahn Garden pond had more microorganisms and a lower quality of water it still had a safer amount of dissolved oxygen then the Duck Pond.
Results We have concluded that the reason the Hahn pond had a safer amount of dissolved oxygen is because of the increased amount of plants that lived in the water and the waterfall cause aeration with also increased the amount of oxygen in the water. The plants were able to increase the amount of dissolved oxygen in the water because as a result of photosynthesis they expel oxygen into the water.
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