Environmental water analysis Free Essay Example

Aims

1. To estimate the total weight of suspended solids in a water sample.
2. To estimate the total weight of dissolved solids in a water sample.
3. To calibrate a pH meter and use it to determine the Ph of a water sample.
4. Buffering capacity of water sample.
5. To determine the acidity of the water sample .
6. To d etermine the alkalinity of the water sample.

Introduction

The European council have set out directives, Council directive 98/83 EC of November 1998 on the quality of water intended for Human consumption and The Nitrates directive (91/676/EEC).

Both of which outline the standards for water quality across the entire region. These directives set out guidelines for the minimum requirements for water quality to ensure the public health is protected (Eur -lex.europa.eu, 2019) . It is up to each memberstate to monitor water quality by sampling throughout the year, this obligation also requires that all sterilization techniques are valid (Eur -lex.europa.eu, 2019) . As for the Nitrates directive, this directive also defines the parameters for the use of fertilizers at during certain periods of the year (Department of Housing, Planning and Local Government, 2019) .

According to Howard Perlman of the USGS water science school, improper timing and use of fertilizers/slurry can cause severe algal b looms, which contribute to fish kills and the degradation of ecosystems (H. Perlman, 2019).

The water samples taken in Ireland are usually carried out by the EPA and report findings back to county councils and group water schemes, these reports must includу concentrations and account for each of the following;

• Microorganisms and parasites
• Suspended organic/inorganic materials
• Dissolved organic materials
• Dissolved inorganic materials
• Taste and odor
• Temperature
• Chlorides
• Nitrates
• Algae
• pH

Method

Apparatus used:

250ml graduated cylinders, 250ml conical flasks, 250ml Beakers, 50ml Burettes, filter paper, oven, pipettes, pH meter, Analytical balance, Top -pan balance, tongs, funnel.

Chemicals used:

pH buffer solutions 7&10, Phenolphthalein, Methyl Orange indicator, 0.02M HCL solution, deionized water, St Johns river sample.

Suspended solids

• Filter paper was removed from packaging and weighed on Analytical balance, ensuring door was closed for an accurate reading. Reading recorded to four decimal places.
• 100ml of sample water was allowed to drain through filter paper into a 250ml beaker, the water that filtered through was kept for a later test.
• After filtration, filter paper was placed into the oven for 30 minutes at 100 degrees Celsius until filter paper was completely dry.
• The filter paper was reweighed on the Analytical balance and the figures recorded.
• A weighted was d etermined in g/ml.

Dissolved solids

• Water from the suspended solids test were kept and used to determine the total concentration of dissolved solids.
• A clean/dry beaker was weighed on the Top pan balance to determine the beakers dry weight and measured in grams, to two decimal places.
• 100ml of sample water was allowed to filter through the filter paper into the 250ml beaker.
• The beaker was weighed along with the sample water using the Top pan balance.
• The beaker was then placed into the oven at 200 degrees Celsius until the water had been driven off.
• The beaker was allowed to cool and reweighed and readings recorded.

pH test of water sample

• The pH meter was unpacked and the probe cleaned using deionized water and a soft piece of cloth. A small beaker was filled with deionized water for cleaning after buffer solutions.
• The pH meter was calibrated using two buffer solutions of known pH, the meter must be in calibration mode while using the buffer solutions.
• First using the buffer solution of 10, waiting for a stable reading then calibrating.
• Rinse probe.
• Use the second buffer solution of 7, wait for a stable reading then calibrate.
• Rinse probe.
• The sample was inserted i nto a small beaker, agitated and probe inserted.
• Readings were measured and recorded.

Buffering capacity

• 50.0ml of water sample was placed into a clean/dry 250ml Beaker.
• The pH was measured and recorded.
• Using a disposable pipette, 1ml of 0.01M HCL was added to the sample one drop at a time, monitoring the pH as each drop was added.
• Continuously stir sample.
• This process was carried out repeatedly until the pH had changed by one entire unit.
• The Buffering capacity was then calculated

Acidity of a water sample

• Using a pipette 50.0ml of sample water was placed into clean/dry 250ml conical flask.
• Two drops of Methyl Orange indicator were added to this sample.
• After two drops of Methyl Orange were added, the sample went a bright red.
• A decision was made to titrate back using 0.02M NaOH in a 50ml burette to reach a yellow endpoint. Colour change should take place at around 4.5pH (Graham, 1999).
• No end point could be established after 25ml of 0.02M NaOH as sample or beaker may have been contaminated.
• The test had to be abandoned due to time constraints and working alone.

Alkalinity of a water sample

• Using the same apparatus and set up as the test for acidity in a water sample.
• 50.0ml of sample water used and 2 drops of phenolphthalein indicator added to sample. The pink color observed.
• 0.02M HCl used in titration back to a colorless solution.
• Titre value recorded
• Due to time constraints, test could not be replicated or repeated.

Calculations

2HCl + CaCO3 — CaCL 2 + H 2O + CO 2

MaVa/n1 = MbVb/n2

a = CaCO 3 b = HCl

Ma = ? Mb = 0.02M

Va = 50ml Vb = 11.6ml

n1= 1 b1 = 1

(? x 50)/1 = (0.02 x 11.6)/1

? = (0.02 x 11.6)/50

= 0.00464

0.00464 x 100 = 0.464 g/L

= 464 mg/L

Discussion

When considering water quality, guidelines provided by the EC in the Council directive 98/83 EC of November 1998 on the quality of water intended for Human consumption and the EEC, No.L229 of July,1980 must be considered, although these experiments were no testing for human consumption.

The outlined total suspended solids (dry residues) must be under 1500mg/dm 3 (Eur -lex.europa.eu, 2019). Measurements of 0.07g can be seen in table (B) and this measurement is within the standards set out by the EC &EEC.

As with current standards on pH, the Freshwater Fish directive (78/659/EEC) of 1978 on the quality of fresh waters needing protection, co mments on the recommended pH being from 6 to 9 for both Salmoid and Cyprinid waters. Test results obtained were 6.86pH and are within the parameters set out.

The current directive also outlines for suspended solids and Nitrates among other things. These are adings are all within current parameters as can be seen in Tables (A) through (D). These findings could be false, figures recorded are all below-recommended guidelines. The EPA define St Johns river as being treated for sewage and effluent runoff, that the river is of concern ‘ and ‘seriously polluted’ (Report on the River Water Quality in Waterford city & County 2011, 2011).

Errors and false results

• The lab manual was difficult to follow at times and this was compounded by my change of partners week to week. A lab practical on this topic would have been beneficial. All figures could have been tabulated across the group to find more precise results.
• Glassware contaminated with unknown material thus making one experiment invalid.
• Door would not close on the analytical balance after drying filter paper, this may have led to inaccurate results as the filter paper was absorbing environmental moisture.

Conclusion

Water quality standards across Ireland have fluctuated throughout the years from an all-time low (14.5%) in moderate water quality rivers and estuaries (2007 to 2009), into the present day where the figure stands at 16.7% (O’Boyle and Tierney, 2016). There was also an increase in sites where phosphate damage had been decreased, from 28% in 2007 to 37% in 2017 (O’Donnell et al., 2017) . These decreases are a reflection of directives and the willingness of governments to follow through.

As the results obtained were in line with recommended standards on water quality, the results may be incorrect due to previously outlined errors. As the Environmental protection agency has stated in the report on Water Quality in Waterford city & county, there has been no substantial change in the water quality of St. Johns river (Report on the River Water Quality in Waterford city & County 2011, 2012)

Refernces

1. Bristow, A., Whitehead, D. and Cockburn, J. (1992). Nitrogenous constituents in the urine of cattle, sheep and goats. Journal of the Science of Food and Agriculture , 59(3), pp.387 -394.
2. Department of Housing, Planning and Local Government. (2019). Nitrates Directive . [online]
3. Available at: -quality/nitrates/n itrates -directive [Accessed 27 Mar. 2019].
4. Eur -lex.europa.eu. (2019). EUR -Lex – 01998L0083 -20151027 – EN – EUR -Lex . [online]
5. Available at: -lex.euro pa.eu/legal -content/EN/TXT/?uri=CELEX:01998L0083 -20151027 [Accessed 28 Mar. 2019].
6. Graham, N. (1999). Guidelines for Drinking -Water Quality, 2nd edition, Addendum to Volume 1 – Recommendations, World Health Organisation, Geneva, 1998, 36 pages. Urban Water , [online] 1(2), p.17. Available at: [Accessed 27 Mar. 2019].
7. Howard Perlman, U. (2019). What causes fish kills? Water science questions and answers, from the USGS Water Science School . [online] Water.usgs.gov. Available at:-chemical -fishkills.html [Accessed 31 Mar. 2019].
8. O’Boyle, S. and Tierney, D. (2016). Indicator 2 – High Quality water sites . [online] Available at: -in-the -percentage -of-high -quality -river -sites -Q5 -Q4 – 5-since -1987_fig2_325877817 [Accessed 29 Mar. 2019].
9. O’Donnell, G., Stephens, A., Free, G. and Tierney, D. (2017). Phosphorus (mg/L) in Lakes . [online]
10. researchgate. Available at: -three -year – averages -of-total -phosphorus -concentrations -at-monitored -lakes -2007 -2016_fig4_325877817 [Accessed 30 Mar. 2019].
11. Report on the River Water Quality in Waterford city & County 2011. (2011). [online] pp.1 -4. Available at: WaterfordCityandCounty.pdf [Accessed 27 Mar. 2019].

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