determination of precipitation contamination
DESCRIPTION
Determination of Precipitation Contamination. Derek Anderson Teri Wilson. Hypothesis. We believe that snow is purer than rain. The Six Common Air Pollutants. Ozone Particulate Matter Carbon Monoxide Nitrogen Oxides Sulfur Dioxide Lead. Nitrogen Oxides (NOx). - PowerPoint PPT PresentationTRANSCRIPT
Determination of Precipitation Contamination
Derek AndersonTeri Wilson
Hypothesis
We believe that snow is purer than rain.
The Six Common Air Pollutants
• Ozone• Particulate Matter• Carbon Monoxide• Nitrogen Oxides• Sulfur Dioxide• Lead
Nitrogen Oxides (NOx)
• Most common are: nitrogen dioxide (NO2) and nitric oxide (NO)
• Primary sources are: kerosene heaters, un-vented gas stoves/heaters, and environmental tobacco smoke
• Causes eye, nose, and throat irritation• National Ambient Air Quality Standard for
Nitrogen Dioxide: <0.053ppm
Lead (Pb)
• A metal found naturally in the environment as well as in manufactured products
• Once taken into the body, lead distributes throughout the body in the blood and accumulates in the bones
• Lead exposure affects the oxygen carrying capacity of the blood
• National Ambient Air Quality Standard for Lead: <0.15μg/m3
Collection Method
• Samples were collected outside of Teri’s garage
• Collected in clean, dry plastic containers
• Poured into sterile glass jars and covered securely
• Stored in the refrigerator until testing
Collection of Precipitation
Sample Type of Precipitation
Date Outside Temperature
Sample 1 Freezing Rain 2-5-11 31.2 F
Sample 2 Rain 2-5-11 35.7 F
Sample 3 Snow 2-5-11 34.8 F
Sample 4 Rain 3-6-11 53.2 F
Sample 5 Rain/Snow Mix 3-30-11 42.9 F
Sample 6 Snow 3-30-11 38.8 F
Testing
• Dionex ICS-90 Ion Chromatography (IC)
• HP 8453 Diode Array UV/Vis Spectrophotometer
• Varian Inductively Coupled Plasma (ICP-OES)
IC Experiment
• Analyte of Interest– Nitrate and Nitrite
• Standards Used– 7 Anion Standard• Standard 1 – 10 ppm• Standard 2 – 15 ppm• Standard 3 – 20 ppm• Standard 4 – 25 ppm• Standard 5 – 100 ppm
IC Parameters
• Pressure: 890 psi
• Flow rate: 1 mL/min
• Pressure Gauge: Slightly above 9
IC Nitrite ResultsType Peak Height (μS)
Standard 1 10 ppm 3.433
Standard 2 15 ppm 4.497
Standard 3 20 ppm 4.907
Standard 4 25 ppm 7.354
Standard 5 100 ppm 25.178
Sample 1 Freezing Rain 6.867
Sample 2 Rain 0.465
Sample 3 Snow 0.043
Sample 4 Rain 0.052
Sample 5 Rain/Snow Mix N/A
Sample 6 Snow N/A
Nitrite Calibration Curve
Calculated Nitrite ConcentrationsSample Type Concentration (ppm)
Sample 1 Freezing Rain 24.95451Sample 2 Rain -1.2832Sample 3 Snow -3.0127Sample 4 Rain -2.97582Sample 5 Rain/Snow Mix N/ASample 6 Snow N/A
* Negative numbers denote negligible values
IC Nitrate ResultsType Peak Height (μS)
Standard 1 10 ppm 2.308
Standard 2 15 ppm 3.024
Standard 3 20 ppm 3.552
Standard 4 25 ppm 5.177
Standard 5 100 ppm 20.651
Sample 1 Freezing Rain 4.792
Sample 2 Rain 0.406
Sample 3 Snow 0.352
Sample 4 Rain 0.320
Sample 5 Rain/Snow Mix 0.472
Sample 6 Snow 0.288
Nitrate Calibration Curve
Calculated Nitrate ConcentrationsSample Type Concentration (ppm)
Sample 1 Freezing Rain 23.62385Sample 2 Rain 2.445678Sample 3 Snow 2.184935Sample 4 Rain 2.03042Sample 5 Rain/Snow Mix 2.764365Sample 6 Snow 1.875905
UV/Vis Experiment
• Analyte of Interest– Nitrate
• Standards Used– Standard 1 – 5 ppm– Standard 2 – 10 ppm– Standard 3 – 15 ppm– Standard 4 – 20 ppm– Standard 5 – 25 ppm
UV/Vis Parameters
• Mode: Standard
• Task: Fixed Wavelength– 224 nm
• Data Type: Absorbance & Second Derivative
• Path Length: 1 cm
UV/Vis Nitrate ResultsType Mean Absorbance
Standard 1 5 ppm 0.500813Standard 2 10 ppm 0.99299Standard 3 15 ppm 1.463267Standard 4 20 ppm 1.773733Standard 5 25 ppm 2.1732Sample 1 Freezing Rain 0.060441Sample 2 Rain 0.031449Sample 3 Snow 0.088468Sample 4 Rain 0.017756Sample 5 Rain/Snow Mix 0.129787Sample 6 Snow 0.050405
Nitrate Calibration Curve
Calculated Nitrate ConcentrationsSample Type Concentration (ppm)
Sample 1 Freezing Rain -1.00193Sample 2 Rain -1.35334Sample 3 Snow -0.66221Sample 4 Rain -1.51933Sample 5 Rain/Snow Mix -0.16137Sample 6 Snow -1.12358
* Negative numbers denote negligible values
Results produced indicate method is not compatible and did not work for our purposes.
UV/Vis Nitrate ResultsType Second Derivative
Standard 1 5 ppm 0.002654Standard 2 10 ppm 0.004063Standard 3 15 ppm 0.001349Standard 4 20 ppm -0.00754Standard 5 25 ppm -0.02788Sample 1 Freezing Rain --Sample 2 Rain --Sample 3 Snow --Sample 4 Rain --Sample 5 Rain/Snow Mix --Sample 6 Snow --
Nitrate Calibration Curve
Calculated Nitrate Concentrations
Even using the Second DerivativeMode, results indicated the method did not
work and was not compatible for our purposes.
ICP Experiment
• Analyte of Interest– Lead (II)
• Standards Used– Blank – 0 ppm– Standard 2 – 40 ppm– Standard 3 – 60 ppm– Standard 4 – 80 ppm– Standard 5 – 100 ppm
ICP Parameters
• Search for Pb(II) at:– 179.605– 182.143– 220.353
• Used Pb(II) at 220 based upon UV/Vis wavelength obtained
ICP Lead ResultsType Intensity
Blank 0 ppm 80.891Standard 2 40 ppm 152.27Standard 3 60 ppm 205.55Standard 4 80 ppm 241.31Standard 5 100 ppm 295.66Sample 1 Freezing Rain 73.989Sample 2 Rain 73.286Sample 3 Snow 75.383Sample 4 Rain 73.505Sample 5 Rain/Snow Mix 75.403Sample 6 Snow 74.098
Lead Calibration Curve
Calculated Lead ConcentrationsSample Type Concentration (ppm)
Sample 1 Freezing Rain -0.666074185Sample 2 Rain -0.994901539Sample 3 Snow -0.014032462Sample 4 Rain -0.892464568Sample 5 Rain/Snow Mix -0.004677487Sample 6 Snow -0.615089574
Discussion
• UV/Vis data did not provide results of significance
• ICP yielded negligible concentrations of lead in samples
• Overall results support Freezing Rain to contain higher levels of Nitrogen Oxides (NOx)
Troubleshooting
• Sample Nitrite values are below IC sensitivities• IC baseline is below 0.00 • UV/Vis protocol not understood
Summary
• The original hypothesis that snow is purer than rain was rejected based on our findings
• No specific precipitation type yielded more pure results than another
• Only that Freezing Rain contained significantly higher concentrations of Nitrogen Oxides
References
Evaluation of a second derivative UV/visible spectroscopy technique for nitrate and total nitrogen analysis of wastewater samples
Michelle A. Ferree and Robert D. ShannonWater Research 2001 35 (1), p. 327-332.
What Are the Six Common Air Pollutants. http://www.epa.gov/ebtpages/airairpollutants.html. 2 April 2011.