Dissolved Oxygen (D.O.) Case Study Example

Introduction

Dissolved Oxygen is an index that determines the health of water of collected water. The concentration of DO usually varies according to salinity, temperature, biological activities and speed of transfers in the atmosphere hence giving a primary determinant of the ecosystem in general. The cooler the waters, the more the capability of holding the dissolved oxygen as compared to warm waters during the summer thus also affecting the salinity. The solubility also affects the DO also increases with the decrease in salinity.

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The temperature also determines the DO quantity and concentration and even variables such as biological activities and salinity plus the speed of transfer from the atmosphere. The colder the water, the more dissolved oxygen it holds, as opposed to warm water. There is also the issue of salinity in that DO decrease with a decrease in salinity.

There are field groups, in this case, group six, which went to the site two where the DO was estimated to be 11.3 PPM for research and the chemical was 11.4 PPM. Another research group got 12.0ppm and 11.3 ppm for probe and chemical analysis respectively from the same site. As for place one, the measurement of the dissolved oxygen is 11.3ppm and also 12.1ppm for the research and chemical calculation purposes.

Biodegradable Oxygen Demand (BOD) and Chemical Oxygen Demand COD)

There is the decomposition of the biodegradable matter by a microbial process that takes in oxygen to facilitate the process especially in sites that has nutrients. The test used in testing microbial methods in water and its impact is known as biochemical oxygen demand.

As measured for the site two, the biodegradable oxygen demand is measured as 1.8ppm hence the Gardinier creek is a sample, and BOD water level is within the standard scale. The Chemical oxygen demand in water in the sample site 02 according to group number 06 is considered to be 10.5 ppm while the results for group five and four are 22.0ppm and 10.5ppm respectively. The maximum level ever reached by the COD level is 69.0ppm as seen by the group number one and it highly due the harsh weather condition. The BOD depends on the nutrients, temperature, enzymes and microscopic populations.

PH Level

PH determines the type of living organisms in water. The toxic ammonia level varies significantly according to the pH changes. The toxicity caused by metal elements such as zinc and copper are released to water hence it becomes acidic. Freshwater organism survives in the necessary pH levels of 6.0 to 8.0. The research in group six shows that the pH results from the site two as 8.6 while that of a group of four and group five were 8.8 and 8.7 respectively. What is interesting is that a couple of hours before, the pH was 8.2 thus the Gardinier Creek pH is within the range of 6.5-9.5 according to the specifications for freshwater regarding Australian standards.

The hardness in water involves ions and salt (dissolved) measurement and also other dilutions of natural or human sources. The calculation is done by the determining the amount of magnesium and calcium in the water.

Hardness

These parameters measure the number of dissolved salts and ions in the water. There are many natural sources of these compounds in the soil, but there is the potential for additional loading (or dilution) from human sources. The site six hardness is 87.4 ppm while group 4 and group five hardness has 38.4ppm and 103.5ppm respectively. However, the 38.4 ppm is an amount on the lower end .The hardness from the research group ranges from 76.8 ppm to 126 ppm hence the group no.2 records a higher in daily intervals marking due to the change in the weather conditions. The calcium was recorded as 52.8ppm, and for the group 05 and 04 they analysed 4.0 ppm and 5.0ppm hence calcium went down from the previous days which registered more than 40 ppm.

Magnesium recorded 34.7 ppm for the group 06 while group 5 and group 4 got 99.5 ppm and 33.4 ppm respectively. Other groups in the results in the mid-week show ppm of 24.0 up to 77.3 thus the 99.5 ppm was above average.

Temperature

The temperatures play a huge role in the determining the existence of living organisms and elements in water in the water column. There external factors that determine water temperatures such as the time, season, sun, water flow and many more. The site two temperatures recorded was 13.4 C as for group six while for group five and four was 13.6C and 14.0 C respectively. In the same day, however, there was a slight change in temperature in the same area earlier with records of 12.9C and 13.0C.

Turbidity

The characteristics of turbidity are related with nutrients which increases the total nitrogen and phosphate element which can be related with solid suspended especially during flood seasons. For instance, as for site no 2, the group no six the turbidity was recorded as 19FTU while the group five and group four 19FTU and 21FTU respectively therefore by recording 287 FTU there shows a significant error. As for Australian standards, the turbidity in fresh water is considered to be ranging from 6 to 50 FTU. The Gardinier Creek turbidity is within range.

Total dissolved solid TDs and Suspended solids

It consists of salts that are inorganic and organic materials which are dissolved in the water. The dissolved water comprises potassium, fluoride, manganese, phosphate, sulphate, chloride and nitrate. The group six according to the research shows a result of 949 pmm while group four gets 54.4 pmm. While the rest range from 0 to 2057 ppm and the fact that 80 ppm is considered as excellent clean drinking water. According to the Australian guidelines, the freshwater regarding TDS is less than the range required of 2400 ppm however according to the research Gardinier Creek is within the specified value.

Alkalinity

The alkalinity is considered as a measure of bicarbonate hence the hydroxides is regarded as a small element in the alkalinity of the water. Alkalinity comes with carbon dioxide which is dissolved in the form of bicarbonate plus H+ ion. This results into an acidity in the water which absorbs and dilutes the calcium in carbonate from other minerals. Bad alkalinity shows the resistance of water to changes in acidity and pH. Gardinier alkalinity is in the specification of according to Australian but is considered slightly higher of about 1-2 in alkalinity with the fresh water being of more than 20 . Below are the methods of calculating Alkalinity.

Methods of Summarising Alkalinity

There is 100 mL aliquot of the sample used to test which was treated with five drops of an indicator known as phenolphthalein.

The indicator is known as methyl orange indicator that is only 5 drops in the quantity which is added to 0.01M H2SO4 until a sign of a yellow color change to become a permanent pink and orange colour. The titrant is usually recorded in Ml. The total alkalinity is calculated according to the titer and volume of phenolphthalein. The concordant outcome is obtained by using triplicates. The results are obtained as seen in the table below.

Result

Burette reading

Average titrate = (10.3+10.2+10.2)/3 mL

= 10.23 mL

Total alkalinity (ppm CaCO3) = VH2SO4H2SO4MW CaCO31000VSample=10.230.00902100.08691000100=92.35ppm

Error Analysis

= Maximum error 100%Value of measurement

=0.07100%10.23=0.68%

AA graph

Conductivity

The conductivity shows the water ability to absorb current. It shows the indication that electrolyte which is present in water. The pollution in water indicates an increase in conductivity hence does not show the specific type of ions present in the water. The group six researched and found 441s while the group four and group five got 402s and 22s respectively which is considered higher in value having 568s. However, in the Gardinier creek, the range of alkalinity is considered within scope.

Conclusion

The water quality of the Gardinier creek is still substandard. Gardinier creek water is not suitable for use as drinking water. Because drinking water need be free of colour or odour, free of a possibly dangerous substance that may present, free of turbidity and suspended solids, soft, noncorrosive as well as low in organic matters. The water is used for regulated industrial water treatment and irrigation but it has brought about suspicious water contamination.