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Water Testing 1 Water Testing: How we measure what you cant see 1 st Elmvale Water Festival August 4, 2007 Ray Clement Laboratory Services Branch, Ontario.

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Presentation on theme: "Water Testing 1 Water Testing: How we measure what you cant see 1 st Elmvale Water Festival August 4, 2007 Ray Clement Laboratory Services Branch, Ontario."— Presentation transcript:

1 Water Testing 1 Water Testing: How we measure what you cant see 1 st Elmvale Water Festival August 4, 2007 Ray Clement Laboratory Services Branch, Ontario Ministry of the Environment

2 Water Testing 2 Overview Steps taken to analyze water What is trace? How do we know were right? New environmental issues and challenges

3 Water Testing 3 Steps in Water Analysis Determine objectives Take a sample for testing Prepare sample for analysis Analyze sample Interpret results with quality control

4 Water Testing 4 Objectives of Water Analysis Ensure safety of drinking water Emergency Response (e.g., industrial spills) Litigation Research The specific methods used depend on the study objectives, type of water tested (drinking, surface, other), and other factors

5 Water Testing 5 Sampling Considerations Sample taken must be representative of the water body being tested

6 Water Testing 6 Sampling Artifact?

7 Water Testing 7 Sampling Considerations Sample taken must be representative of the water body being tested Sampling containers must be appropriate and specially cleaned before use (e.g., plastic for metals, glass for organics) Shipping and storage considerations

8 Water Testing 8 Prepare Sample for Analysis Extraction step Interference removal step Concentration step

9 Water Testing 9 Extraction Step Methods used depend on substance we are testing for For organic chemicals like PCBs or pesticides, use organic solvent not miscible with water Sometimes, water filtered and particulates extracted separately

10 Water Testing 10 Water Extraction Setup In this example, hexane was added to a 1.0 Liter drinking water sample When the water and solvent are mixed vigorously, organic molecules move from water into the solvent

11 Water Testing 11 Water Extraction Setup After the water and solvent have mixed well, the solvent is withdrawn from the top – this process is repeated 2-3 times to make sure all organic compounds are removed

12 Water Testing 12 Solids Extraction Setup If particulates are in water, they are filtered and the filter extracted by Soxhlet Solvent in the flask at the bottom is continually recycled, bringing organic chemicals to the bottom Process similar to brewing coffee

13 Water Testing 13 Interference Removal Step The compounds you are looking for are not the only ones in the sample Other compounds – Interferences – can result in incorrect results Interferences are removed by various chemical operations known as Cleanup

14 Water Testing 14 Interference removal example for dioxin analysis

15 Water Testing 15 Concentration Step The sample must be reduced in size before analysis because it is too dilute to achieve really low detection limits ppb = parts-per-billion [1 part in 10 9 ] ppt = parts-per-trillion [1 part in ] ppq = parts-per-quadrillion [1 part in ]

16 Water Testing 16 Typical Concentration Factors Typical water sample size for trace analysis is about 1.0 Litres Final sample microlitres (10 -6 L) Concentration factor is about 10 4 to 10 5

17 Water Testing 17 Other environmental sample types

18 Water Testing 18 Sample Analysis Considerations Many different types of chemical instrumentation are available for the final analysis step For metals, one of most effective is called an Inductively-Coupled Plasma Mass Spectrometer (ICP-MS)

19 Water Testing 19 ICP-MS Metals Analysis ICP-MS uses a hot plasma (flame) to atomize metals in sample Metals identified by atomic mass Number of atoms detected related to concentration in sample

20 Water Testing 20 GC-MS Organics Analysis For organics, instrumentation used is called a gas chromatograph-mass spectrometer (GC-MS) Dozens of types of GC-MS systems exist, costing from $100K to $1.5 million Capabilities of systems different, but basic principles the same

21 Water Testing 21 Inject Sample Into GC-MS

22 Water Testing 22 Complexity of Soil Samples

23 Water Testing 23 Basic Operation of GC-MS

24 Water Testing 24 Each Molecule has Fingerprint

25 Water Testing 25 High Resolution Mass Spectrometer

26 Water Testing 26 Characteristics of Methods Detection Limit Accuracy –How close to the real concentration? Precision –Related to measurement uncertainty

27 Water Testing 27 Detection Limits

28 Water Testing 28 Detection Limits

29 Water Testing 29 Precision and Accuracy

30 Water Testing 30 Data Interpretation: Public Understanding Analysis of dioxin in lake water 3 samples on consecutive days Detection limits 0.1 – 0.3 ppt Actual results: Day 1 – 0.2 ppt Day 2 – 0.4 ppt Day 3 – not detected What was the newspaper headline?

31 Water Testing 31

32 Water Testing 32 New Millennium – New Challenges Pharmaceuticals & Personal Care Products Perfluorinated compounds Water Disinfection Byproducts Brominated Flame Retardants (BFRs) Algal Toxins: microcystins, anatoxins Organometallic Compounds: tin, lead

33 Water Testing 33 The Future of Environmental Trace Analysis More of less, faster and cheaper

34 Water Testing 34 How Many Chemicals? Date: 08/1/ :14:18 EST Count: 32,261,560 organic/inorganic substances 15,057,189 commercially available chemicals

35 Water Testing 35 New Challenges: New Tools Fourier Transform (Ion Cyclotron Resonance) Mass Spectrometer

36 Water Testing 36


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