Water Quality Of Four Different Sites Biology Essay

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The aim of this experiment is to determine physical and chemical indicators to measure and compare the condition of surface freshwater at four different sites. The four sites are; 1) Gross river, Navua Reserve, 2) Hanna Park, north Richmond, 3) Yarramundi, Nepean River and 4) South Creek.

Method:

Physical Sampling Methods

On the 29th of April 2011 water samples were collected from four sites using a bucket and string to collect water. The four sites were; 1) Gross river and Navua Reserve, 2) Hanna Park, North Richmond, 3) Yarramundi, Nepean River and 4) South Creek. A cylinder was used to collect one litre, from the bucket and the litre of water was filtered through a filter paper. Filtered water sample were stored in plastic bottles on ice.

Site descriptions

Site 1) Gross river and Navua Reserve,

Sample site one Site 1had fairly fast flowing water and sandy riverbanks. River is wide but water is clear and a shallow channel (approximately 10-15m x 30-50cm deep). Sample was taken at 9.58 am and the weather was sunny at time of testing. The sample site is surrounded by natural reserve and agricultural landuse. There is a small amount of aquatic plants upstream and no submerged plants in the water. SDC11015.JPG

Site 2) Hanna Park, North Richmond

Sample site two is characterised by cleared recreational areas, bridge with frequent motor vehicle use, flowing water, large number of weeds, trees and grass at the edge of the river. Emergent and submerged macrophytes are present varieties include pond weed and salvinia. Rubbish is present on the banks, balloon vine an exotic weed seed capsule and invertebrate fish were spotted in the water. The river is approximately 100m wide and weather was sunny at time of testing.SDC11015.JPGSDC11015.JPG

SDC11015.JPG

Site 3) Yarramundi, Nepean River

SDC11015.JPG

Sample site three was characterised by flowing water of varying speeds, weeds and dense macrophyte growth in slower moving areas. Macrophyte beds were visible upstream, sample site was shady, with some algal growth on a sandy riverbed. The surrounding landuse of the area is primarily agriculture and a bridge with frequent motoe vehicle used is present. Irrigation pumpes were observed along the river and there was alot of decaying organic matter on the river banks. The area contains many rare natives such as the long finned eel, eel tailed Catfish, freshwater mullet and Australian bass. Exotic species include mosquito fish, exotic carp and goldfish.SDC11015.JPG

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Site 4) South Creek.

Sample site three was water under a road bridge, flow has been altered and their is variability of water flow in this creek. Creek is narrow with a small (weir, brown and turbid water. Water is drawn out for use on adjacent farms and a major highway bridge is located over the creek. There is overhanging grass, trees on bank, some macrophytes in a shallow area below weir, weeds, rubbish and banks are showing signs of erosion.

The weather on the 29th of April 2011 at all four sites was partly cloudy with significant rainfall over the last six days prior to the field trip.

Physical and chemical indicator methods

Air temperature, Water temperature, pH & Dissolved Oxygen.

These indicators were tested onsite using direct analysis equipment. Dissolved oxygen was measured in (mg/L), temperature of the water ( and air temperature (. pH was measure using a pH meter.

Suspended Solids

The filter paper from the vacuum filter collected in the initial physical sampling of the surface freshwater sites paper was used to test suspended solids by weighing dried retained residue.

Nitrites

Nitrites was tested using a colorimetric method. Nitrite was determined by diazotizing with sulphanilamide and coupling with N-(1-naphthyl)-ethylenedia-mine dihydrochloride which formed a reddish purple azo dye produced at 2.0-2.5 pH. These dyed samples were tested colourmetrically using a cary spectrophotometer set at wavelength 543nm.

Nitrates

Nitrates were tested using a cadmium reduction method, where was reduced to nitrite by cadmium graules that were treated with coppersulfate ( and packed in a glass column. Produced nitrite was determined by diazotizing with sulphanilamide and coupling with N-(1-naphthyl)-ethylenedia-mine dihydrochloride which formed a coloured azo dye. These dyed samples were tested colourmetrically using a cary spectrophotometer set at wavelength 540nm. This cadmium reduction method for testing nitrate concentrations was completed by my lab group. There was no changes that I am aware of to the standard method, but there was a problem with the water samples where it was believed that the samples had been mixed up and thus measure had to be undertaken to correct the error.

Phosphate

Phosphate was tested using a ascorbic acid method. Ammonium molybdate and antimony potassium cartrate were reacted in acid with orthophosphate to form heteropoly acid-phosphomolybdic acid that is reduced to molybdenum blue by ascorbic acid. These dyed samples were tested using a cary spectrophotometer set at wavelength 880nm.

Silicates

Silicate concentrations was determined using a molybdosilicate method. Ammonium molybdate at approximately 1.2 was used to react with silica and produce heteropoly acids. Oxalic acid was added to destroy molybdophosphoric acid but leave the molybdosilicic acid. Samples were measured at a wavelength of 410nm by a spectrophotometer.

Data analysis

Data was tabulated and calibration curves produced where necessary using excel. A summary table was created and final results graphed to show relationships between sites.

Results

Figure six shows the calibration curve for determining nitrate concentrations in water samples. The standard samples (0.5, 1, 2, 5 & 10 mL) versus the concentration (mg/L) was graphed using excel and a line of best fit inserted. The concentration (mg/L) of the standard samples was calculated from the formula below.

Calculations of concentrations of standard samples

Stock Nitrate solution: 1 mL = 100 μg. Concentration 100 μg/mL or 100 mg/L

Intermediate Nitrate Solution: 50.00 mL of stock taken and diluted to 500.00 mL

= Cf = (100 mg/L x 0.050 L)/ 0.500 L = 10 mg/L

Standard solutions calculations for the calibration curve

0.5 mL, 1.0 mL, 2.0 mL, 5.0 mL and 10.0 mL of intermediate nitrate solution was further diluted to 100 mL.

Example: 0.5 mL

= = (10 mg/L x (5.0 x L))/ 0.100 L = 0.05 mg/L

Samples were diluted further. (25.00 mL of each, 100 mL volumetric flasks)

Example: 0.05 mg/L

= (0.05 mg/L x 0.025 L)/ 0.100 L = 0.0125 mg/L

Figure seven shows the calibration curve for determining nitrite concentrations in water samples. The standard samples (0.5, 1, 2, & 2.5 mL) versus the concentration (mg/L) was graphed using excel and a line of best fit inserted. The concentration (mg/L) of the standard samples was calculated from the formula below.

Calculations of concentrations of standard samples

Stock Nitrite solution: 1 mL = 250 μg ∴ Concentration 250 μg/mL or 250 mg/L

Standard Nitrate Solution: 1 L = 500 μg ∴ Concentration 500 μg/L or 0.5 mg/L

1mL of stock taken and diluted to 500 mL

= = (250 mg/L x (1.0 x L)/ 0.500 L = 0.5 mg/L

Standard solutions for the calibration curve

0.5 mL, 1.0 mL, 2.0 mL and 2.5 mL of the standard nitrite solution diluted to 50mL.

Example: 0.5 mL

= = (0.5 mg/L x (5.0 x L))/ 0.050 L = 0.005 mg/L

Figure eight shows the calibration curve for determining nitrite concentrations in water samples. The standard samples (4, 8, 16, & 20 mL) versus the concentration (mg/L) was graphed using excel and a line of best fit inserted. The concentration (mg/L) of the standard samples was calculated from the formula below.

Calculations of concentrations of standard samples

Stock Silica solution (0.473 g in 100 mL volumetric flask), Standard Silica Solution (10 μg silica = 1 mL) ∴ Concentration 10 μg/mL or 10 mg/L

Standard solutions for the calibration curve

4.0 mL, 8.0 mL, 16.0 mL and 20.0 mL of the standard silica solution was diluted to 50mL.

Example: 4.0 mL

= = (10 mg/L x (4.0 x 10-3 L))/ 0.050 L = 0.8 mg/L

Figure nine shows the calibration curve for determining nitrite concentrations in water samples. The standard samples (3, 6, 12, & 24 mL) versus the concentration (mg/L) was graphed using excel and a line of best fit inserted. The concentration (mg/L) of the standard samples was calculated from the formula below.

Calculations of concentrations of standard samples

Stock Phosphate solution: 1 mL = 50 μg ∴Concentration 50 μg/mL or 50 mg/L

Standard Phosphate solution: 1 mL = 2.5 μg ∴Concentration 2.5 μg/mL or 2.5 mg/L

25 mL of stock taken and diluted to 500 mL

= = (50 mg/L x 0.025 L)/ 0.500 L = 2.5 mg/L

Standard solutions for the calibration curve

3.0 mL, 6.0 mL, 12.0 mL and 24.0 mL of the standard phosphate solution was diluted to 50mL.

Example: 3.0 mL

= = (2.5 mg/L x (3.0 x L))/ 0.050 L = 0.15 mg/L

Table one is a tabulated summary table of all the physical and chemical parameters tested on the water samples of all four sites.

Figure ten represents the range of air temperatures recorded at Site 1,2,3,4. Site 1 Gross river, Navua Reserve had the lowest temperature (21.5°C) out of the four sample sites on the 29th of April 2011. Site 4 south creek, had the highest air temperature of all the sample sites (24.5°C). Site 2 and 3's air temperature was the same (22°C). Figure eleven represents the range of water temperatures recorded at Site 1,2,3,4. Site 1; Gross river, Navua Reserve had the lowest water temperature (18.5°C) out of the four sample sites on the 29th of April 2011. Site 3; Yarramundi, Nepean River, had the highest water temperature of all the sample sites (19.50°C). Site 2 and 4's water temperature was the same (19°C).

Figure twelve represents the range of pH levels recorded at Site 1,2,3,4. Site 1 Gross River, Navua Reserve had the lowest pH 5.85 out of the four sample sites on the 29th April 2011. Site 4 South creek, had the highest pH of all the sample sites (7.01). Site 2 and 3's pH levels were very similar, site 3 was slightly higher (6.52) and (6.48). Figure thirteen represents the range of dissolved oxygen (mg/L) levels of water recorded at Site 1,2,3,4. Site 3 had the lowest dissolved oxygen 7.30 mg/L out of the four sample sites on the 29th April 2011. Site 1 had the highest dissolved oxygen of all the sample sites 8.00 mg/L. Site 4 and 2 dissolved oxygen levels were very close, with a 0.4 difference, site 4 was higher 7.8 mg/L than site 2 7.40mg/L.

Figure fourteen represents the range of suspended solid (mg/L) levels of water recorded at Site 1,2,3,4. Site 1 had the lowest dissolved oxygen 0.4 mg/L out of the four sample sites on 29th April 2011. Site 2 was the next lowest of the sample sites (1.2 mg/L) and was followed by Site 3 at 2.9mg/L. Site 4 significantly had the highest suspended solid's level of all the sample sites, 33.6 mg/L. Figure fifteen represents the range of nitrite concentrations recorded at Site 1,2,3,4. Site 1 Gross River, Navua Reserve had a nitrite concentration below the detection limit (0) out of the four sample sites on the 29th April 2011. Site 3 South creek, had the highest nitrite concentration of all the sample sites (0.028 mg/L). Site 3 (0.0027 mg/L) nitrite concentration was higher than site 2 (0.0014 mg/L) but lower then site 3.

Figure sixteen represents the range of nitrate concentration (mg/L) levels of water recorded at Site 1,2,3,4. Site 1 had the lowest nitrate concentration 0.058 mg/L out of the four sample sites on 29th April 2011. Site 4 is significantly higher in nitrate concentrations (0.518 mg/L) than all other sites. Site 3 was higher (0.0953 mg/L) than site 2 (0.0767 mg/L). Figure seventeen represents the range of phosphate concentrations recorded at Site 1,2,3,4. Site 1 Gross River, Navua Reserve had the lowest phosphate concentration (0.006 mg/L) out of the four sample sites on the 29th April 2011. Site 4, had the highest phosphate concentration of all the sample sites (0.0212 mg/L). Site 3 (0.0162 mg/L) nitrite concentration was higher than site 2 (0.008 mg/L) but lower then site 3.

Figure eighteen represents the range of silicate concentration (mg/L) levels of water recorded at Site 1,2,3,4. Site 1 had the lowest silicate concentration 0.763 mg/L out of the four sample sites on 29th April 2011. Site 4 is significantly higher in silicate concentrations (2.11 mg/L) than all other sites. Site 2 was slightly higher (1 mg/L) than site 3 (0.946 mg/L).

Discussion

Comparison of the data and explanation for differences between sites.

Due to the complexity of aquatic environments, there is no one suitable standard to use in deciding whether an aquatic environment is healthy. In very few situations there is enough knowledge to indicate if a "certain minimum change from the prevailing or target condition will cause an adverse ecological effect" (The Australian and New Zealand Environment Conservation Council 2000 p3.3-19).

A body of water's temperature can be influenced by varying environmental factors such as: flow, depth, season, time, geographical location and input of water. Significant lowering of temperature can be harmful, but in most cases an increase in temperature (thermal pollution) will cause more harm (Masterton B 2001). Increases in water temperature decrease oxygen levels (Andrews W 1972 2.8). Site 1 Gross river, Navua Reserve had the lowest air and water temperature (21.5°C), (18.5°C) Site 4 had the highest air temperature (24.5°C) site 3; Yarramundi, Nepean River, had the highest water (19.50°C). Site 2 and 3's air and water temperature was the same.

The presence of suspended solids determines the ability of the water body to support life (Andrews W 1972 2.7). Total suspended solids, like turbidity consist of silt, clay, organic matter, and pollutants and effluent (Masterton B 2001). Site 4 South creek had the highest suspended solid's level of all the sample sites, 33.6 mg/L sources of these suspended solids in this creek are urban, agricultural runoff from surrounding landuse and the river bank is experiencing erosion. High levels of suspended solids reduces photosynthetic activity of macrophytes and can also reduce nutrient levels because the available nutrients are absorbed into the sediment.

Aquatic plant growth is responsive to the amount of sunlight available, atmospheric and the waters temperature, and organic and inorganic nutrients. Nitrogen and phosphorous occur naturally in the environment but levels can increase or decrease due to urban, sewage and agricultural runoff (Masterton B 2001).

Nutrient enriched. A reading of >0.02mg/L can result in an aquatic environment that was normally dominated by macrophytes, to become dominated by phytoplankton. A further increase can result in an accumulation of algae, depleting oxygen (Natural Resource Management Ministerial Council, Environment Protection and Heritage Council, Australian Health Ministers' Conference p263).

silicate

It has been estimated that a healthy freshwater river does not exceed nitrogen levels of 0.30mg/L (Andrews W 1972 2.4).

It is suggested that the pH of a freshwater body of water should vary between 6.7 and 8.6. This is around the neutral mark. Generally, this level should support a healthy environment for organisms to grow and reproduce. As a body of water ages, generally, the water becomes more acidic. This is because there is a build up of organic materials releasing carbon dioxide. The pH balance can also be altered by human means such as sewage treatment plants, such as this case. A body of water with a pH value over 7.0 to 8.5 is most likely influenced by pollution such as effluent, chemicals and fertilizers (Andrews W 1972).

Site 1-4 healthy???

In 1992 The Australian and New Zealand Conservation Council recommended the levels of dissolved oxygen in a fresh body of water should be between (The Australian and New Zealand Conservation Council 2000 page 3.3-25). Research has suggested that many Australian native fish species can not tolerate an oxygen concentration below 5mg/L (The Australian and New Zealand Conservation Council 2000 page 3.3-25).

This is because aquatic organisms depend of oxygen and because a reduction of oxygen in an aquatic environment can "cause reducing conditions in sediments, so the sediments release previously-bound nutrients and toxicants to the water column where they may add to existing problems" (The Australian and New Zealand Conservation Council 2000 page 3.3-25).

It's important to note that the amount of dissolved oxygen is greatly dependant on temperature, and biological activity. If an excessive amount of organic material is added to an aquatic environment then this can deplete oxygen levels. excessive oxygen demand for microbial activity. Simply put, the more biodegradable material entering an aquatic environment, requires more microbial activity to break it down, thus the oxygen demand can not be met (The Australian and New Zealand Conservation Council 2000 page 3.3-25).

Finally, The Nepean River is eutrophic (nutrient enriched) and both confluences are partially degraded. That is, they are nutrient enriched and Boundary Creek is just below the minimal recommended dissolved oxygen level, 4.94mg/L.

Current land use surrounding the area- local sources of water quality degradation

There are various point and non-point local sources that contribute to water quality degradation of surface freshwater. The geographical locations of the four sample sites studied mean that they are surrounded by heavily urbanised areas such as Windsor, Richmond, Penrith and its surrounding areas, Emu Heights, Emu Plains, Cranebrook and Kingswood. These areas are surrounded residential, industrial and commercial landuse. There are quite a number of the sewage treatment plants treating effluent from the local surrounding areas (Penrith sewage treatment plant 2007). There is also a large amount of land that is being used for agricultural purposes. Sydney Water owns and operates the Sewage Treatment Plants in the area.

Figure twenty shows the located of all the Sydney Water Sewage Treatment Plants in the Hawkesbury-Nepean River area. Figure twenty-one shows the locations of the sample sites to compare them to figure figure twenty. Sewage Treatment Plant in a year can released up to and above 9 541 million litres of treated effluent into the waters of these sample sites (Penrith Annual STP Performance 2007-2008). It can be said that the biggest influence over the water quality degradation in the Hwakesbury-Nepean River area is urbanization as a result from growing population numbers in the districts surrounding this series of water bodies.

Recent rain in the area can have two different effects it is likely to increases river flow rate and amount of water, which assumedly would dilute pollutants that degrade water quality. Although recent rain can also cause more pollution runoff, from practices such as agriculture, overflow from sewage treatment plants can occur and high amounts of rain is likely to have increase erosion of soils releasing more nutrients into the water ways.

MAP

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