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Sample Collection and Preservation

Sample Collection and Preservation. Importance Safety Quantities Sampling utensils Sample Types Collection Methods Preservation Storage Hold times COCs. Why we sample. To verify compliance for NPDES To determine if our processes are efficient. Some Basics . Must be representative

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Sample Collection and Preservation

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  1. Sample Collection and Preservation

  2. Importance • Safety • Quantities • Sampling utensils • Sample Types • Collection Methods • Preservation • Storage • Hold times • COCs

  3. Why we sample • To verify compliance for NPDES • To determine if our processes are efficient

  4. Some Basics • Must be representative • Consider your collection point • Consider the analysis • Sample containers must be clean and free from interference • Must be handled right to avoid degradation, contamination, compromising • Correct collection and preservation • Low level mercury • Biological

  5. Safety

  6. Safety • Assess the potential for hazards • Physical • leaning, stretching, pulling, lifting • Awkward positions • Constituents • Toxic, biological, pathogens • Entry: skin, eyes, nose, mouth

  7. Safety General PPE • Gloves • Eye protection • Ventilate area if vapors may be present • Specific PPE • Containment suits • Special gloves, boots

  8. Sampling utensils

  9. Collection Storage

  10. Collection Containers • Manual • Dippers • Buckets • Automated • Flow based • Time based

  11. Manual • Grab samples or composite grab • Mix well before transfer • Proper container • Rusty coffee cans are probably not the right container…….

  12. Automated • Usually 24 hour • Flow based more accurate than time based • Clean tubing • 2 sets- one cleaning, one in use • Wear on tubing could change volume pumped • Calibrate pump frequently • NPDES states to pull at least 100ml

  13. Collection Containers • Dedicate containers • Clean containers well • Use detergents that are free of interference/contamination potential • Rinse with DI water 3 X • Dry completely • Container should not interfere with analysis

  14. A word about “C” Organic Carbons • Can not use plastic containers to collect VOC, TOC, or any C’s • It will contaminate sample

  15. Storage Bottles • Glass or plastic • Hard glass (pyrex) is preferred • Silica, sodium, and boron may be leached from soft glass but not plastic • Use glass for all organics (VOC, semi VOC, pesticides, PCBs, oil and grease) • Avoid plastic when possible- phthalate esters can contaminate sample

  16. Storage Bottles • Use amber glass bottles to avoid photodegradation • Caps are important too! • No paper liners • Use foil or PTFE liners • Be aware that metal liners can contaminate samples for metals

  17. Quantities

  18. How Much do you need • Most methods tell you the minimum quantity needed • Give yourself some extra • For pre-preserved containers • Make sure that the quantity collected is the right volume. Don’t fill ¼ full if the bottle needs to be full.

  19. Sample Types

  20. Grab Sample • Provide “snapshot” • Used for process control • Short hold time • Used when samples are not variable • Used for testing that requires immediate analysis • Cl2, pH, temp, organic, volatiles • Several grabs over time course to show variability

  21. Composite Sample • Represent heterogeneous matrix • Can be set to represent flow based • Can result in loss or dilution of analyte • Can result in increase interferences • Can not be used on certain tests • Cl2, pH, temp

  22. Control Samples • Field blank • Usually DH20 transferred from one container to another while at sampling site • Usually low level contaminates • Lab blank • Usually DH2O analyzed in tandem • Tests for contamination/proper technique • Indicates background levels

  23. Collection Methods

  24. How to collect - Grab • Pole dippers • Secure container • Submerge container • Buckets • Start downstream and move into flow • Direct • Start downstream and move into flow

  25. How to collect - Composite • Set Sampler to collect flow based or timed • Determine potential for contamination from tubing • Tubing should be clean • Tubing should be located in area that is representative • Don’t rest on bottom • Avoid dead areas • Needs to be in center of flow

  26. How to collect • Same location every time • TOC and some volatiles should not be put into plastic containers • Transfer quickly with minimal exposure to air • Don’t transfer multiply times • Cap container quickly • Label the container • Time, date, location, collector

  27. Composite • Collection bottle should be refrigerated • Clean tubing and collection bottle • Collection bottle should be large enough to mix sample • Mix the right way • Too little and not enough mix of settlables • Too much and incorporate air/analyte loss

  28. Receiving Waters • For stream sampling, make sure you enter downstream of where you will take sample • Move upstream to gather your samples if you have multiple sites • Change gloves frequently

  29. Filling bottles • Minimize exposure to air when transferring • Don’t overfill pre-preserved bottles • Put preserve in bottle after sample • Leave headroom for biologicals • No air bubbles for volatiles

  30. What do you do with those caps? • Handle caps with care • Setting them on the ground risks contamination • Setting them upright risks contamination • Holding them risks contamination • Depends on the surroundings……

  31. Low Level Mercury • Two people • Dirty hands/clean hands technique • One person only handles the sample containers • One person collects sample, pours into sample container

  32. Composite Grabs • NPDES states “at least” 8 grabs of at least 100 mls over periodic intervals during working hours • Collect each grab and refrigerate • Mix equal amounts of grabs together • Mix well • Example: radium in sludge

  33. Soapbox Time • Wear gloves • Protects you • Protects the sample • DEET • Lotions/soap • Do you know where your hands have been?

  34. Preservation

  35. Preservation Limited to: • pH control • Chemical addition • Amber or opaque bottles • Refrigeration • Filtration • Freezing

  36. Why Preserve • Retard biological action • Retard hydrolysis of chemical compounds • Reduce volatility of analyte

  37. Preservation • Depends on Analysis • Some acids can degrade plastics- be careful

  38. Storage

  39. Storage • Ice or refrigerate immediately • Keep temperature from fluctuating • Preserve immediately if bottle is not pre-preserved • Some samples are stored at room temp

  40. Hold times

  41. Hold times • Begins when sample is collected • Depends on analyte • Rule of thumb: • The quicker it’s analyzed, the better

  42. COCs

  43. Many Faces of COCs • Labels • Seals for bottles • Facility bench sheets/ Field log books • Analysis request sheet (COC) • Record of delivery to laboratory • Receipt and logging of sample • Assignment of sample

  44. Chain of Custody • Traceability • Shows who handled sample from collection, preservation, storage, and analysis. • Allows for routine control of samples and also aides in litigation issues

  45. Labels • Permanent maker • Attached to container • Lists the following: • Date and time of collection • Facility • Location • Type of sample • Preservative • Analysis • Collector

  46. COC • Usually from Lab • Fill out completely • Sample name, date and time of sample • Type of sample • Preservative • Bottle and volume • Analysis needed

  47. NPDES permit fine print

  48. (10) Monitoring and records. (a) Samples and measurements taken for the purpose of monitoring shall be representative of the monitored activity. (b) The permittee shall retain records of all monitoring information, including all calibration and maintenance records, and all original strip chart recordings for continuous monitoring instrumentation, copies of all reports required by this permit, and records of all data used to complete the application for this permit, for a period of at least 3 years from the date of this permit, measurement, report or application. This period may be extended by request of the Agency at any time. (c) Records of monitoring information shall include: The date, exact place, and time of the sampling or measurements; The individual(s) who performed the sampling or measurements; The date(s) analysis were performed; The individual(s) who performed the analyses; The analytical techniques or methods used; and The results of such analyses. (d) Monitoring must be conducted according to test procedures approved under 40 CFR Part 136, unless other test procedures have been specified in this permit. Where no test procedure under 40 CFR Part 136 has been approved, the permittee must submit to the Agency a test method for approval. The permittee shall calibrate and perform maintenance procedures on all monitoring and analytical instrumentation at intervals to ensure accuracy of measurements.

  49. NPDES Requirements • All calibration and maintenance Records • Yearly maintenance of balance etc • Replacement date of probes • Thermometer calibrations • Pipettes • Original strip chart recordings • Required Reports • Keep for 3 years

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