Faster Dissolved Oxygen Test Kit Analysis Essay Example
Faster Dissolved Oxygen Test Kit Analysis Essay Example

Faster Dissolved Oxygen Test Kit Analysis Essay Example

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  • Pages: 12 (3266 words)
  • Published: August 21, 2018
  • Type: Case Study
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The purpose of this text is:

The aim of my project is to compare the levels of dissolved oxygen (DO) using two methods - the traditional HACH method and the newly developed CHEMets test kit, in typical field conditions. I predict that there will be no significant difference in DO levels measured by both methods. According to a literature review conducted by Hill (1992), water is abundant on Earth, making our planet unique. There is an increasing focus on environmental preservation among people, and governments have implemented laws to protect natural resources. Locally, there is evidence suggesting that enhanced sewage treatment has resulted in improved water quality.

National monitoring data shows that investments in controlling point-source pollution have not led to a significant improvement in water's dissolved oxyge

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n levels over the past 15 years. It is possible that we are only keeping up with the amount of pollution being produced (Knopman, 1993). In the early biosphere, low levels of oxygen made life unpleasant. Oxygen-producing photosynthetic bacteria played a vital role in creating an oxygen-rich atmosphere, allowing for the emergence of more advanced life forms (Brown, 1994). The increase in Earth's oxygen levels remains a complex mystery. Scientists have different opinions on when and how oxygen arrived on Earth; however, its importance for our survival cannot be denied (Pendick, 1993). Just like atmospheric oxygen is essential for human existence, dissolved oxygen is crucial for the survival of most fish and aquatic organisms. Dissolved oxygen serves these creatures' needs just as atmospheric oxygen does for humans – without it, both humans and fish would be unable to survive.

Fish and humans have different sources

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of oxygen. Fish get their oxygen from water, while humans inhale it from the atmosphere (Mitchell and Stapp, 1992). The requirements for dissolved oxygen vary among different aquatic organisms. Pike and trout thrive in environments with medium to high levels of dissolved oxygen, while carp and catfish can survive with lower levels (Mitchell and Stapp, 1992). Insufficient levels of dissolved oxygen impede the growth of Asiatic clams (Belanger, 1991), whereas excessive amounts in the American River caused the death of salmonoid fishes (Colt, Orwicz, and Brooks, 1991). Brood catfish are particularly vulnerable to low levels of dissolved oxygen as they are bred on fish farms and serve as a significant food source for many people (Avault, 1993). Dissolved oxygen primarily comes from two sources: the atmosphere where waves mix oxygen with water in lakes and swiftly moving rivers; and aquatic plants such as algae and benthic plants that produce oxygen through photosynthesis.The solubility of gases, like oxygen, is inversely proportional to temperature. This means that when the temperature rises, gas solubility decreases and vice versa. The concentration of dissolved oxygen is also influenced by atmospheric pressure and atmospheric oxygen levels. When there is an increase in atmospheric pressure or oxygen levels, the amount of dissolved oxygen also increases (Roskowski & Marshall, 1993).

D.H. Farmer conducted a study on fluctuations in dissolved oxygen content in a body of water before, during, and after a storm. The study found that during the storm, increased wave activity led to an increase in dissolved oxygen content (Farmer and McNeil, 1993).

Turbulent flow in streams primarily results in biocenogenesis through attached or benthic organisms. A method was developed to assess the role

of benthic organisms in maintaining total dissolved oxygen levels. Benthic plants play a crucial role in providing dissolved oxygen.

These plants produce oxygen through photosynthesis. Benthic plants, such as cattail, bulrush, arrowhead, water lily, pond weeds, and muskgrass, respire oxygen. (Nebel, 1990) Several factors can alter the amount of dissolved oxygen in water. Dissolved oxygen levels increase from morning until afternoon due to photosynthesis. Photosynthesis ceases at night, but animals and plants continue to respire and consume oxygen. Dissolved oxygen levels are also influenced by water temperature and volume. Dry weather decreases dissolved oxygen levels while wet weather increases them. (Mitchell and Stapp, 1990) The breakdown of organic matter by bacteria reduces dissolved oxygen but enriches the water with plant nutrients. Some level of breakdown is beneficial to prevent the water from becoming nutrient poor or oligotrophic. However, excessive organic breakdown decreases dissolved oxygen and leads to an excess of nutrients. Eutrophication refers to a body of water where organic nutrients cause a significant reduction in dissolved oxygen, favoring plant life over animal life. Algae blooms are also responsible for excessive organic material.

According to Nebel (1990), when algae die, they become part of organic wastes. Microorganisms can break down most organic material through biodegradation, which can occur aerobically or anaerobically. Aerobic oxidation causes a depletion of dissolved oxygen. If there is excessive organic matter and ongoing degradation, the process shifts to an anaerobic one. In the absence of oxygen, anaerobic bacteria thrive and suppress animal life (Hill, 1992). The decrease in dissolved oxygen in water leads to significant changes in aquatic organisms. Insects that rely on high levels of dissolved oxygen, such

as mayfly nymphs, stonefly nymphs, caddisfly nymphs, and beetle larvae are replaced by pollution-tolerant worms, fly larvae, nuisance algae, and other anaerobic organisms (Mitchell and Stapp, 1992).

So, what is considered a good level of dissolved oxygen? A concentration under 4 ppm is not ideal. However, excessive dissolved oxygen also has its drawbacks. According to Hidaka, Shimazu, Kumanda, Takeda, and Aramaki (1991), there is a nonlinear relationship between oxygen concentration and median lethal concentrations values, indicating increased toxicity at moderate oxygen levels. This research suggests that the concentration of dissolved oxygen is an important factor when assessing the photo-induced toxicity of anthracene to fish. McCloskey and Oris (1991, p.145) also support this idea. Present-day examples demonstrate the impact of pollution on the level of dissolved oxygen, which subsequently affects the ecosystem. Here are two specific instances that exemplify the devastating consequences of neglecting our ecosystem. One such example is the Chesapeake Bay, which happens to be the largest estuary in North America and was once highly productive before the 1970s. It provided habitats for various waterfowl and supported vast food chains that began with sea grasses.

In the early 1970s, there was an extensive underwater "grass" covering in the Chesapeake Bay, spanning over half a million acres. This grass played a vital role in supporting marine life by providing food, shelter, and spawning grounds for young fish. It also supplied them with dissolved oxygen needed for breathing. However, starting from this time period, the sea grasses began to die off. By 1980, they had completely disappeared from all areas except the lower bay. The loss of these grasses caused a decline in animals

that relied on them and resulted in suffocation for lobsters, oysters, and fish due to insufficient dissolved oxygen in the bottom water. Consequently, the once clear waters of the Chesapeake Bay became murky and cloudy for extended periods of time. The reduced light availability further contributed to sea grass death as it decreased photosynthesis activity which then reduced the supply of dissolved oxygen in water. Subsequently, bacterial decomposition increased and consumed even more dissolved oxygen, depriving fish and shellfish of this vital resource. This entire process is known as eutrophication taking place in the Chesapeake Bay.

Nebel (1990) states that numerous ponds and small lakes have suffered a similar fate as the Black Sea over the past 40 years. The pollution of the Black Sea, caused by over 300 rivers depositing nitrates, phosphorous, and oil into it, has resulted in its decline. In Varna, Bulgaria, there is a darkly humorous saying suggesting that drowning in the sea's toxins would kill someone faster than suicide. The main sources of this pollution are the Danube, Dniester, and Dnieper Rivers. Waste from the Danube River has significantly increased in recent years. Johann Strauss Jr.'s famous composition "Blue Danube" would hardly be recognizable now as the river has turned pea-green or black instead of blue. Additionally, rainbow-like patterns appear on the water's surface due to sunlight reflecting off oil puddles. While poisons are a concern, nutrients like phosphorous and nitrogen present the greatest problem in this situation.

The ocean's nutrient input increase leads to the growth of harmful surface algae, blocking sunlight from reaching seabeds and causing their decline. This also stops the production of dissolved oxygen

(Pomfret, 1994). Pollution affects rivers as well. In Yugoslavia, the River Borovniscica is polluted with organic substances, while the River Bistra suffers from contamination by inorganic substances. The Cuyahoga River famously caught fire on June 22, 1969 (Gordon and Steele, 1993). Dissolved oxygen levels can vary within a single stream, river or body of water. In areas outside the main current of a stream, dissolved oxygen levels may be low. Biologist E.P. Pister demonstrated this when trying to rescue an endangered species of pupfish. Regrettably, he mistakenly placed cages with previously captured specimens in eddies away from the main current,resulting in some fragile creatures dying before he realized his mistake (Pister, 1993).

The cause of fish deaths in the American River was not a lack of dissolved oxygen, but rather an excessive amount. The abundance of dissolved oxygen proved to be deadly for hatchery salmonoids due to gas bubble disease. High levels of dissolved oxygen in the river were caused by air entrainment, solar heating, and photosynthesis. To solve this problem, degassing structures were installed at the hatchery's water supplies to remove the excess oxygen. It is vital to first identify the source of the issue before attempting a solution in order to effectively address such disasters. Even during cleanup efforts, there might not be an observable pattern in the increased level of dissolved oxygen in the water.

Various companies offer water quality test kits, some of which are time-consuming. In field conditions where quick response is crucial, people seek faster methods. Although certain companies have developed quicker tests, accuracy should be questioned. CHEMetrics provides a dissolved oxygen kit consisting of ampoules filled

with a nearly colorless indigo carmine solution in reduced form. Snapping the ampoule's tip fills it with the water sample, and any dissolved oxygen causes oxidation of the reagent, resulting in a blue color. Comparing the ampoule to standard color bars determines the amount of dissolved oxygen. However, distinguishing between shades of blue in higher ranges (e.g., 5-10 ppm) can be challenging as they may appear similar and there isn't a specific bar for 9 ppm. Instead, there are bars for 8 ppm and 10 ppm. If the shade is darker than the 8 ppm bar but lighter than the 10 ppm bar, it can be declared as 9 ppm.

Determining whether something is 7.5 ppm is not possible because there is no shade of blue between 7 ppm and 8 ppm. The HACH method provides a simpler way to measure dissolved oxygen in water, although it takes time. To calculate the amount of dissolved oxygen, count the drops of Sodium Thiosulfate Standard Solution needed for the sample to change from yellow to colorless. Each drop represents one ppm of dissolved oxygen. Accuracy and safety are both important factors to consider in this method since it involves chemicals that have warnings about keeping them away from children, using them only in laboratories, their potential for causing eye burns, and the risk of skin irritation. The instructions also offer guidance on handling the chemicals if there is inhalation, ingestion, or contact. Thus, cautious use is necessary due to safety concerns associated with the HACH method compared to the CHEMets kit which does not have any such warnings.

The main concern is the possibility of

breaking the glass ampoule if it is squeezed too firmly. When choosing a test kit, various factors should be taken into account, not just speed. These factors encompass quality, time, safety, expense, and accuracy, among others. The HACH TESTING KIT comprises several materials such as Dissolved Oxygen Reagent Powder Pillows, Sodium Thiosulfate Standard Solution, glass stoppered Dissolved Oxygen Bottles, square mixing Bottles, Clippers, a stopper for the dissolved oxygen bottle, and a measuring Tube. On the other hand,the CHEMets TESTING KIT includes self-filling ampoules for colorimetric analysis and a chart with color bars for comparison. The TABLE should be covered with newspaper and/or paper towels while various WATER sources include the Kankakee River,melted snow,tap water,tap water stirred for one minute roof runoff,and fish aquariums.The necessary equipment to record results consists of paper,a pencil,and a clipboard.Safety measures involve wearing rubber gloves,goggles,and rubber aprons.Unfortunately,the procedure for using the HACH TESTING KIT is not provided in this given text.

To fill the Dissolved Oxygen bottle with the water to be tested, follow these steps:
- Allow the water to overflow from the round bottle with a glass stopper for about 2 or 3 minutes.
- In order to prevent air bubbles, slightly tilt the bottle and quickly insert the stopper, which will push out any trapped air bubbles.
- If there are any air bubbles present during Steps 2 or 4, discard the sample and repeat the test.
- Open one Dissolved Oxygen 1 Regent Powder Pillow and one Dissolved Oxygen 2 Reagent Powder Pillow using clippers.
- Carefully pour both pillows into the bottle while avoiding air bubbles.
- Hold onto the bottle and stopper tightly, then shake vigorously to mix everything

together.
- If there is oxygen in the sample, a brownish orange flocculent precipitate (floc) will form.
- Some powdered reagent may stick to the bottom of the bottle, but this will not affect test results.

3) Let the sample stand until half of the settled floc in the bottle, leaving the upper half clear. Shake the bottle again. Allow it to stand until the upper half of the sample becomes clear. Note: samples with high chloride concentrations, such as sea water, will not have the floc settle. The test results will not be affected as long as the sample is left to stand for 4 or 5 minutes.

4) Use clippers to open a Dissolved Oxygen 3 Reagent Powder Pillow. Remove the stopper from the bottle and add the contents of the pillow. Carefully reseal the bottle and shake it to mix. If oxygen is present, the floc will dissolve and a yellow color will appear.

5) Fill the plastic measuring tube completely with the sample prepared in Steps 1 through 4. Pour the sample into the square mixing bottle.

6) Add drops of Sodium Thiosulfate Standard Solution to the mixing bottle, swirling it after each drop. Hold the dropper vertically above the bottle and count each drop as you add it. Keep adding drops until the sample changes from yellow to colorless.

7) Each drop used in Step 6 causes a color change that represents a dissolved oxygen concentration of 1 mg/L in the sample. To perform the CHEMets testing, follow these steps:
1)

Immerse the snapper into the sample.
2) Insert a CHEMet ampoule into the snapper, tapered end first.
3) Snap the tip of the ampoule by pressing down on it.
4) Take out the ampoule from the snapper and invert it several times to mix its contents, allowing the bubble to move from end to end.
5) Wait for 2 minutes for full color development.
6) Determine dissolved oxygen content using the color chart inside the box. Match filled CHEMet ampoule with color bars on chart. Place ampoule on both sides of color bar for accurate results, illuminated with strong white light from above.

Results:
Location Chem Hach Temp C Difference
Kankakee River (near our dock) 10 12 2.2 -2
Kankakee River (near our dock) 10 11 3.3 -1
Kankakee River (near our dock) 9 13 4.4 -4
Kankakee River (near our dock) 10 12 .5 -2
Roof Runoff 4 5 5.6 -1
Kankakee River (near our dock ) 10

Tap Water 7 7 18.9 0
Snow (melted) 8 8 21.1 0
Tap Water (stirred for 1 minute) 7 8

Fish Aquarium

Fish Aquarium
Fish Aquarium
Tap Water
Graphs and Conclusions

In conclusion, there is a notable disparity in dissolved oxygen (DO) levels when measuring with the

traditional HACH method or the newly developed CHEMets test kit in normal field conditions. The CHEMets test kits prove challenging to interpret, particularly in higher ranges. Furthermore, CHEMets does not compare favorably to HACH in situations where dissolved oxygen exceeds 8 ppm, and it cannot measure levels above 10 ppm. However, CHEMets is suitable for temperatures of around 150C or higher. On the other hand, the HACH test kit is the preferred method for field analysis as it consistently provides accurate measures of dissolved oxygen at all levels. While the HACH method requires more caution during use, it does reveal significant differences in dissolved oxygen measurements. The data collected through analysis is susceptible to random fluctuations of varying magnitude, making it difficult to determine whether observed differences are actual sample variations or merely chance occurrences.

The discipline of statistics allows one to assess the probability (the odds) that measured differences arise from chance alone. Once one has a feel for the odds that the differences arise from chance, one can decide to reject or conditionally accept a hypothesis based on that data. The statistical test being used for this study (Wilcoxson - Matched Pairs Signed Ranks) was chosen for its computational ease and power. A nonparametric test was chosen because there was a question about the level of measurement (ordinal or interval) and whether or not the assumptions for a parametric test could be met. Procedure to apply Wilcoxson - Matched Pairs Signed Ranks test. (see table) 1. Pair all data from each sample according to date. 2. Take the difference between each pair of measurements. 3. Rank the size of each difference paying no heed

to sign (drop zero differences - split ranks on ties) 4. Compute the sum of the rank with the less frequent sign (T).

5. With a two-tailed test, the alpha is set at 0.05.
6. In an appropriate statistical table (table G page 254 of Nonparametric Statistics by Sidney Sigel 1956 McGraw Hill), the value for T is looked up.
7. The null hypothesis (Ho) is rejected if T is equal to or less than the tabled value.
Chem Hach Temp C Chem - Hach Rank
7 7 23.3 0
7 7 18.9 0
8 8 21.1 0
4 5 5.6 -1
3.5 7 8 21.1 -1
3.5 7 8 23.3 -1
3.5 7 8 23.3 -1
3.5 10 11 3.3 -1
3.5 10 11 5.6 -1
3 1 23.3 2
8 10 12 5.0 -2
8 10 12 2.2 -2
8 9 13 4.4 -4
N=10 (number of non zero differences) T=8 (sum of ranks with less frequent sign) a=0.05 (significance level) Ho is rejected.
Literature Cited APHA (1990). Standard methods for the examination of water and wastewater (16th ed.).

New York: APHA, Inc.
Avault, J. (1993, Jul/Aug).Take care of those brood cats.Aquaculture, pp.73
Belanger, S. (1991, July).The effect of dissolved oxygen, sediment, and sewage treatment plant discharges upon growth, survival, and density of Asiatic clams.Hydrobiologia, pp.113-126.
Brown, L. (1994).State of the world.London: W.W. Norton &Company.pp.42.
Colt, J. & Orwicz K. & Brooks, D. (1991, Winter).Gas supersaturation in the American River.California Fish and Game.pp.41-50.
Hikada, Shimazu, Kumanda, Takeda, Aramaki.(1991).Studies on the occurrence of hypoxic water mass in surface mixed layer of inner area of Kagoshima Bay.Memoirs of the Faculty of Fisheries: Kagoshima.pp.59-81.
Have, M. (1991).Selected water-quality characteristics in

the upper Mississippi River Basin, Royalton to Hastings, Minnesota.USGS Water-Resources Investigation.pp.125.
Hill, J. (1992).Chemistry for changing times.(6th ed.) New York: McMillain Publishing Co.pp.477, 487- 489.
Knopman, D. (1993, Jan/Feb).20 years of the clean water act.Environment.pp.16.
McCloskey, J. & Oris, J. (1991, Dec.).Effect of water temperature and dissolved oxygen concentration on the photo-induced toxicity of anthracene to juvenile bluegill sunfish.Aquatic Toxicology .pp.145-156.
Nebel, B. (1990).Science: the way the world works.(3rd ed.) New Jersey: Prentice Hall.
Pomfret, 0.J. (1994, Nov.25).Rivers deadly to Black Sea.The Daily Journal.pp.20.
Roskowski, R. & Marshall, B. (1993, Jul/Aug).
The article "Gases in water" by Schopf (1993) can be found in the journal Aquaculture on pages 70-76. This article discusses the diversity of life seen in fossils, as reported in Science News on page 276 by Schopf (1993). A field manual for water quality, authored by Stapp and Mitchell in 1992, is available in its 6th edition. It was published by Thomson - Shore Inc. in Michigan. Steele (1993) provides information on the American environmental policy in an article featured in American Heritage on page 30.

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