Environmental Control (2nd year EH module): lab on the impact of air quality on environmental pollution levels
Aim: test the hypothesis that the levels of metals in street dust vary in relation to traffic density.
Structure of lab session
- 10 minute: Introduction to the hypothesis and procedures (including lab induction, demonstration of sample weighing, acid digestion and ICP analysis)
- 5 minutes:Weigh replicate samples and add acid (6 samples plus 1 control blank per group)
- 15 minutes: Digestion of samples
- 10 minutes: Cooling of samples / demonstration of ICP instrument
- 15 minutes: Filtration of samples
- 25 minutes: Analysis of samples
- 30minutes: Discussion of results, appropriate standards and how to convert concentrations from ICP data in ppm to mg/kg
Kit required for lab work
- 2 balances (1 per group)
- Tubes for digestion
- Nitric acid
- 1% nitric acid
- Spatulas
- Filter papers
- 14 funnels
- 14 volumetric flasks (volume?)
- ICP-AES(inductively coupled plasma - atomic emission spectroscopy) calibrated for Cd, Cu. Pb, Zn, Cr and Fe
- Lab inductionReflective Overview
Briefly comment on:
-The topic of each lab -How undertaking the labs has improved your understanding of environmental pollution•How this new knowledge will impact on your professional practice
Part1 - Practical"Determination of ammonia and phosphate in water samples"
Question 1.1: Produceone table to summarise the results of the ammonia and phosphate tests of all samples. Include your results,the class mean valuesand discuss your findings.
Question1.2: Does the value obtained for the river sample comply with the WFD levels for good water quality? Would you have any concerns for the water quality of this river based on your finding?
Question1.3: Explore the natural cycles of nitrogen and phosphorusand pollution due to human activities. In riversand lakes, whatarethe most likelynatural and anthropogenicsourcesof ammoniaand phosphate (identify at least two each)?
Part 2 - Practical "Impact of Air Emissions"
Question2.1:
Briefly describe your 3 sampling sites andstate your reasons for selecting themin relation to the overall experimental aim.
Question2.2:
a) Present your data onallmetal concentrations in street dusts from all 3 sample locations as mg/l in a single tablei.e. as they were calculated by the ICP.b)Present your results on metal concentrations in street dusts from all 3 sample locations as mg/kg in a single table, thus showing the final concentration in street dust.Include an example of your working.
Question2.3:
a) Explain the differences between metal concentrations determined at each sitecommentingontrends shown by the metals in relation to each sample location.b)At each site, compare the results of your ‘a' and ‘b' samples. Do they agree with each other for all metals? If not, why not? If so, why?
Part 3 - Practical "Noise"
Question 3.1:Listen to the 4 sound sources that are used within the experiment and describe the sound as you perceive it. Try to imagine that you are describing it to someone who has not heard it and you wish to convey the impact and sound definition that they would be able to here.This might be the case if you came back from a visit and had to describe the noise source to your line manager.
Question 3.2
The experiment required measurements indb(Z), dB(A) and also undertook frequency band analysis of each sound source.
a) Explain why we undertook measurements indB(Z) (also known as dB(Linear)) and dB(A). Whenthe fan and the rotary grinder were measured in dB (Linear) they provided broadly similar levels of soundenergy.Why did they appear to be different in terms of their impact?
b) Explainwhy the use of frequency band analysis is useful in theprocessofnoise control.
c) Provide a graphical display of the frequency distribution of the 3 machines recorded in the experiment
Question 3.3:
a) The hoover was enclosed using various materials. Discuss the results, in terms of noise control, for each of the following:single layer enclosure; single layer enclosure with lid; double layer enclosure; double layer enclosure and foam.
b) Using the following information concerning distance,calculate the impact of the vacuum cleaner, without enclosure, measured at 1m on the nearest dwelling. Please complete this for the theoretical distribution acting as an optimal point source and under the experimental conditions when the source behaved like a line source.
The vacuum cleaner is positioned on top of a building 30m in height.The boundary of the garden is 45m away and the facade of the building is 68m.
Consider the above results against the WHO standards for community noise and whether there would be any issue in the garden, at the façade, or inside the dwelling if the insertion loss provided by the windows were 12dB open and 25dB closed.
Explain why the 2 figures are different and the implications that this might have in terms of predicting the impact of a new sound source on a locale.
Referencing: Harvard