Post on 18-Jan-2016
Water Quality Causal factors & Urban Impact
Water Resource Management Agency
Michael Skeete
What is Water Quality?
Water Quality is
• The condition of water for a purpose1
– Drinking– Agriculture– Etc.
• According to certain characteristics1
– Physical– Chemical– Biological
1. http://floridakeys.noaa.gov/scisummaries/wqfaq.pdf
Will this Reduce the Water Quality?
YES!Maybe?
Water Quality Standards• Standards (WQS) are what the Water Quality test
results are compared to2
• Different purposes have different standards:– WRMA Ambient (Environmental)
WQS– WASCO Drinking WQS– Hotel Industry Recreational WQS
2. http://water.epa.gov/scitech/swguidance/standards/rev.cfm
What affects Water Quality?
• Humans– Industry– Agriculture– Hygiene
• Climate• Weather• Other Life Forms
Testing Water Quality Physical Parameters3
• Temperature • Total Suspended Solids• Turbidity• Odour• Taste• Flow (in the case of rivers)
3. Davis et al.(2005)
How to testPhysical Parameters
• Temperature– Testing the temperature is always done in situ using
analogue or digital thermometer • Odour– Should be done in situ or within 5 mins. of sample
collection• Taste– Do this at your own risk– Often done at treatment plants
• Total Suspended Solids– Water is filtered, then the residue is dried and
weighed then compared to the original sample• Turbidity4
– Is measured by the amount of light that is scattered by the sample
How to testPhysical Parameters
http://learnweb.harvard.edu/ent/gallery/pop4/Turbidity_MWRA.pdf
4.
• Flow Gauging:– The river is sectioned off
and flow is measured at each section using an impeller. The readings for each section are then added together to produce a reading for the whole river section
How to testPhysical Parameters
Parameter UnitTemperature °C – Degrees Celsius
Total Suspended Solids Ppm – Parts per million
Turbidity NTU – Nephelometric Turbidity Units
Odour Subjective but useful description
Taste Subjective but useful description
Flow Gauging m3/s – Meters Cubed per Second
How to testPhysical Parameters
Units
Testing Water Quality Chemical Parameters3
• pH• Specific Conductance• Nutrients– Nitrates– Phosphates
• Heavy Metals • Pesticides• Herbicides
• Industrial Wastes• Alkalinity• Pharmaceuticals• Surfactants• Oxygen • Etc……..
3. Davis et al.(2005)
How to testChemical Parameters
• Potential Hydrogen (pH): Tested using Reagents or Calibrated Electronic Meters (CEM)5
𝑝𝐻=𝑙𝑜𝑔10 ¿
5. http://www.all-about-ph.com/what-does-ph-stand-for.html
How to testChemical Parameters
• Specific Conductance– Is a measure of the salinity of
the water, the more ions in the water the more conductive it is
– This is usually measured using a CEM in the field
How to testChemical Parameters
• Nutrients: Tested for in a Spectrophotometer – Nitrates– Phosphates• Samples of water are taken back to a lab (or mobile lab)
where specific volumes of the sample reacts with a measured amount of reagent and the change between the original samples light scattering capacity and the regent mixed sample gives the concentration of nutrients
How a Spectrophotometer Works6
6. http://lsteam.org/
• Dissolved Oxygen (DO)– DO Meter measures the oxygen by how much it
dilutes the charge (electricity Negative change, oxygen does not)
How to testChemical Parameters
How to testChemical Parameters
Parameter UnitpH The pH Scale (no Unit)
Specific Conductance μS/cm – Microsiemens per Centimetre
Nitrates & Phosphates mg/l – Milligrams per litre
Dissolved Oxygen (DO) ppm – Parts per million
Most Chemical Constituents Mass per volume of water
Units
Testing Water Quality Biological Parameters3
• bio-indicators – These are large insects and animals that live in the
water body, if they are present then the water must be of a certain quality
• Bacterial Life (health concerns)– E Coli– Coliform Bacteria
3. Davis et al.(2005)
• Bio-Indicators7
– Stratified locations of fish could mean• A Thermocline layer (temperature boundary)• A Hypoxic layer (Oxygen boundary)• A Eutrophication layer (Nutrient boundary)
– No presence of previously present animals• Water quality has dropped and either moved the animals away or
killed them off
NB: These are all indicators, they do not produce numbers but they show the water has changed and can provide clues to the problems
Testing Water Quality Biological Parameters
7. Barbour, M.T et al (1999)
However8
This requires a lot of study:In a well studied ecosystem, change in numbers of organisms can give very accurate information about pollutants and other stresses from the environment.
8. Holt, E. A. & Miller, S. W. (2011
• Bacterial life1. A sample is taken 2. Kept cool and away from exterior contamination3. Brought back to the lab ASAP4. Sample is shaken to allow for minimum settling5. Sample is added to agar plate (pour or scrape)6. Plate is incubated for 24 to 48 hours7. Count the colonies of bacteria
Testing Water Quality Biological Parameters
Urban Contribution9
• Runoff contributions due to impervious surfaces:– Driving and Vehicle Maintenance– Gardening– Waste Disposal– Hygiene (Poor or failed septic systems)– Construction sites
9. http://www.nrdc.org/water/pollution/storm/chap3.asp
Urban Impacts9
• Riverbank/bed erosion• Increased siltation• Aesthetic degradation• Disruption of aquatic life • Harm to coastal environments (Coral etc.)
– Fisheries– Tourism
• Increased water temperature• Human health
9. http://www.nrdc.org/water/pollution/storm/chap3.asp
Thank You for Listening
Any Questions?
References 1. NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION. (2009). Water Quality: Frequently Asked
Questions. <http://floridakeys.noaa.gov/scisummaries/wqfaq.pdf>2. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY (nd). Water Quality Standards Review and Revision.
Available at: United States EPA Website. <http://water.epa.gov/scitech/swguidance/standards/rev.cfm> (updated October 2012, accessed 20th November 2013).
3. DAVIS, ALLEN P., MCCUEN, RICHARD H. (2005). Stormwater Management for Smart Growth. Maryland: Springer.
4. HARVARD ENT GALLARY. (nd). Turbidity Test 7. Available at: Harvard ENT learnweb website <http://learnweb.harvard.edu/ent/gallery/pop4/Turbidity_MWRA.pdf> (Accessed 20th October 2013)
5. ALL ABOUT PH. (nd). What does pH stand for and calculating pH. Available at All About pH Website <http://www.all-about-ph.com/what-does-ph-stand-for.html> (Accessed 20th October 2013)
6. LEARNING SOLUTIONS NC COMMUNITY COLLEGES. (2013). How does a spectrophotometer work. Available at Learning Solutions website <http://lsteam.org/projects/videos/how-does-spectrophotometer-work> (Accessed 20th October 2013)
7. Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling (1999). Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and Fish. 2nd Edition. EPA 841-B-99-002. U.S. Environmental Protection Agency; Office of Water; Washington, D.C.
8. Holt, E. A. & Miller, S. W. (2011) Bioindicators: Using Organisms to Measure Environmental Impacts. Nature Education Knowledge 3(10):8
9. NATURAL RESOURCE DEFENCE COUNCIL (nd). Stormwater Strategies , Community Responses to Runoff Pollution. Available at NRDC Website. <http://www.nrdc.org/water/pollution/storm/chap3.asp> (Accessed 3rd March 2015).