mercury monitoring the fdep laboratory perspective timothy w. fitzpatrick (850) 245-8083...
TRANSCRIPT
Considerations:Considerations: Compliance versus Environmental Compliance versus Environmental
MonitoringMonitoring
Sample Kit PreparationSample Kit PreparationSampling ProtocolsSampling ProtocolsLaboratory DesignLaboratory DesignAnalytical RigorAnalytical RigorData InterpretationData Interpretation
FDEP’s ExperienceFDEP’s Experience
Constructed Class 1000/100 in mid-Constructed Class 1000/100 in mid-1990s;1990s;
Adopted Method 1631 w/ some Adopted Method 1631 w/ some modifications from initial EPA version modifications from initial EPA version (semi-automated the method, (semi-automated the method, investigated aqua regia digestion);investigated aqua regia digestion);
Developed fully automated Developed fully automated methylmercury analysis in late 1990s methylmercury analysis in late 1990s using direct ethylation P&T GCAF;using direct ethylation P&T GCAF;
EPA incorporated semi-automated EPA incorporated semi-automated advances in Method 1631E; Automation advances in Method 1631E; Automation of Draft Method 1630 under evaluation by of Draft Method 1630 under evaluation by EPA Region IV;EPA Region IV;
FDEP’s ExperienceFDEP’s Experience
Primary Client Focus: Environmental Primary Client Focus: Environmental Monitoring and ResearchMonitoring and Research
Detection Limits:Detection Limits:
THg ~ 100 pg/L (0.10 ng/L)THg ~ 100 pg/L (0.10 ng/L)
MeHg ~ 20 pg/L (0.02 ng/L)MeHg ~ 20 pg/L (0.02 ng/L)Initiated Everglades Mercury Round Initiated Everglades Mercury Round Robins ca. 2000Robins ca. 2000
Introduction to Method Introduction to Method 16691669
““Clean hands/dirty hands” samplingClean hands/dirty hands” sampling Ultra-trace detection levels and Ultra-trace detection levels and
methodsmethods Tables listing applicable levels in Tables listing applicable levels in
sampling methods sampling methods ““Mindset” and technique Mindset” and technique
Protection of sample against Protection of sample against contaminationcontamination
Sampling KitsSampling Kits
Double Bagged, Pre-Cleaned Vessels of Double Bagged, Pre-Cleaned Vessels of Glass, Teflon or Surface Fluorinated P-E Glass, Teflon or Surface Fluorinated P-E Prepared in LaboratoryPrepared in Laboratory
Prices: Glass < Fluor. PE <<< TeflonPrices: Glass < Fluor. PE <<< TeflonPre-Cleaned Sampling Equipment May Be Pre-Cleaned Sampling Equipment May Be
Needed (Needed (Teflon Tubing, Silicon Pump Tubing, Filtration Teflon Tubing, Silicon Pump Tubing, Filtration Devices, etc.)Devices, etc.)
Laboratories are Sources of Contamination! Laboratories are Sources of Contamination! (Air, DI Water, Reagents, etc.)(Air, DI Water, Reagents, etc.)
Clean Benches or Clean Room Strongly Clean Benches or Clean Room Strongly Recommended for Equip. Preparation Recommended for Equip. Preparation (Absolute Necessity for Environ. Monitoring)(Absolute Necessity for Environ. Monitoring)
Sampling by Method 1669Sampling by Method 1669
Performance Based MethodPerformance Based MethodCompliance vs. Environmental Compliance vs. Environmental Monitoring: When is the Full-Blown Monitoring: When is the Full-Blown Method Necessary (or Practical)?Method Necessary (or Practical)?Our Experience w/ Hg – Most Our Experience w/ Hg – Most Contamination Occurs in the Contamination Occurs in the LaboratoryLaboratoryVessels Need to be Prepared in a Vessels Need to be Prepared in a ‘Clean’ Laboratory Environment‘Clean’ Laboratory Environment
Sample Collection SOPSample Collection SOP
DEP SOP FS 8200DEP SOP FS 8200 http://www.dep.state.fl.us/labs/qa/sops.htmhttp://www.dep.state.fl.us/labs/qa/sops.htm
Adapted from EPA 1669Adapted from EPA 1669 ““Performance-based” conceptPerformance-based” concept Verify performance with blanks & other Verify performance with blanks & other
QCQC Sampling team practice recommendedSampling team practice recommended
Field Contamination IssuesField Contamination Issues
Source of analyte-free water for Source of analyte-free water for field blanks and equipment blanksfield blanks and equipment blanks
Sampling equipment and sample Sampling equipment and sample containerscontainers
Sampling personnel and clothingSampling personnel and clothing Ambient sampling environmentAmbient sampling environment Sampling techniquesSampling techniques
Sampling Equipment Sampling Equipment DecontaminationDecontamination Minimum amount of pre-cleaned Minimum amount of pre-cleaned
equipment (only) recommended ;equipment (only) recommended ; Controlled environment for cleaning;Controlled environment for cleaning; See FS 8200 cleaning procedures;See FS 8200 cleaning procedures;
Specific cleaning procedure for mercury;Specific cleaning procedure for mercury; All pre-cleaned items wrapped for field use;All pre-cleaned items wrapped for field use; Field-based cleaning not recommended;Field-based cleaning not recommended; Dippers not recommended; Collect directly Dippers not recommended; Collect directly
into sample bottles where possible;into sample bottles where possible;
On-site PrecautionsOn-site Precautions All equipment and supplies in covered All equipment and supplies in covered
storage until usestorage until use Keep hands and equipment away from Keep hands and equipment away from
contamination sourcescontamination sources Adhere to “clean hands/dirty hands” Adhere to “clean hands/dirty hands”
protocolsprotocols Change gloves when neededChange gloves when needed Collect least contaminated source firstCollect least contaminated source first
Develop a ‘contamination sensitive’ mindsetDevelop a ‘contamination sensitive’ mindset
Precautions for Sampling Precautions for Sampling Equipment & Protective Equipment & Protective ClothingClothing
Caution advised with pigmented Caution advised with pigmented materials, bottle labels, inkmaterials, bottle labels, ink
See FS 8200 for recommended See FS 8200 for recommended sampling equipment and materials to sampling equipment and materials to avoidavoid
Wrap cleaned pump tubing endsWrap cleaned pump tubing ends Don’t contaminate tubing with pump Don’t contaminate tubing with pump
or extension deviceor extension device
Sample Preservation & Sample Preservation & TransportTransport Add HCl preservative upon return to Add HCl preservative upon return to
lablab Max of 48 hours on ice prior to Max of 48 hours on ice prior to
preservativepreservative Protect bagged samples from Protect bagged samples from
contamination during transport and contamination during transport and storage storage
Isolate or segregate samples as Isolate or segregate samples as neededneeded
0
50
100
150
200
250
Equip.Bland
G253E G254C 012 G252G G252C G255 002 002FieldDup.
004 FieldBlank
Comparison of Collection and Analytical Techniques for Everglades Sites Mercury in ng/L
Method 1669/1631
Conventional Collection/1631
1669/245.1*
1669/245.1 - Conventional Preparation @ SFWMD; Analysis using pre-concentration
CVAAS; MDL = 50 ng/L
Laboratory Design Laboratory Design Considerations: Clean Bench vs. Considerations: Clean Bench vs.
Clean LabClean LabCost vs. Type of Work EnvisionedCost vs. Type of Work EnvisionedWorkload IssuesWorkload Issues
Sampling Bottle and Equipment Sampling Bottle and Equipment PreparationPreparation
Sample Preparation and Determinative Sample Preparation and Determinative StepsStepsFugitive Vapor ControlFugitive Vapor ControlParticulate ControlParticulate ControlInstrument LocationInstrument Location
Without proper controls, spurious laboratory Without proper controls, spurious laboratory contamination can exceed water quality standards!contamination can exceed water quality standards!
Instrument SchematicInstrument Schematic
Analytical Rigor245.1 versus 1631
Blank subtraction allowedNo blank subtraction
CVAF detectionCVAA detection
PQL ~ 0.2 – 0.5 ppt (ng/L)PQL ~ 20 - 500 ppt (ng/L)
Pre-concentration by Au trapTypically no pre-concentration
Bromine monochloride digestionPermanganate/persulfatedigestion
Class 1000 lab environmentClean room not required
Clean sample collection – EPA method 1669
No clean sample collection required
Method 1631Method 245.1
Blanks in 1631Blanks in 1631
Blanks play a critical role in monitoring Blanks play a critical role in monitoring contamination, and quantifying the mercury contamination, and quantifying the mercury content of samplescontent of samples
Mercury levels in (digested) method blanks Mercury levels in (digested) method blanks may be higher than those present in ambient may be higher than those present in ambient samplessamples
Even the best de-ionized water has Even the best de-ionized water has measurable concentrations of mercurymeasurable concentrations of mercury
Digested blanks have Hg concentrations Digested blanks have Hg concentrations between 0.2 and 0.6 ng/Lbetween 0.2 and 0.6 ng/L
Blanks in 1631EBlanks in 1631E
Confounding of mercury levels in the Confounding of mercury levels in the reagent and the de-ionized water – reagent and the de-ionized water – cannot easily separate mercury content cannot easily separate mercury content of reagents from mercury in de-ionized of reagents from mercury in de-ionized water water
Assumption: Most of the “background Assumption: Most of the “background contamination” in method blanks is from contamination” in method blanks is from the reagents and not from the DI waterthe reagents and not from the DI water
No “bubbler blanks” used in the No “bubbler blanks” used in the automated methodautomated method
Quantification in 1631EQuantification in 1631E
Analyze 5 method blanks and calculate the Analyze 5 method blanks and calculate the blank correctionblank correction
Subtract this “blank correction term” from Subtract this “blank correction term” from all samplesall samples
Sensitivity RequirementsSensitivity Requirements
Natural WatersNatural Waters
Typical Levels:Typical Levels:0.5 – 2 ng/L THg0.5 – 2 ng/L THg< 0.02 – 0.2 ng/L MeHg< 0.02 – 0.2 ng/L MeHg
Recommended Recommended Quantitation Limits:Quantitation Limits:~ 0.5 ng/L THg~ 0.5 ng/L THg~0.05 ng/L MeHg~0.05 ng/L MeHg
Discharge MonitoringDischarge Monitoring
Water Quality Standards:Water Quality Standards:12 ng/L THg Fresh12 ng/L THg Fresh25 ng/L THg Marine25 ng/L THg Marine
Recommended Recommended Quantitation Limits:Quantitation Limits:< 10 ng/L THg Fresh< 10 ng/L THg Fresh< 25 ng/L THg Marine< 25 ng/L THg Marine
Data InterpretationDetection and QuantitationDetection and Quantitation
Detection Limit and Quantitation Detection Limit and Quantitation Limits are Influenced by:Limits are Influenced by:
Sampling vessels, collection and handling Sampling vessels, collection and handling techniquestechniques
Quality of the laboratory environment – Quality of the laboratory environment – particulate content of laboratory airparticulate content of laboratory air
Cleanliness of digestion reagents and Cleanliness of digestion reagents and procedureprocedure
Instrumental techniqueInstrumental technique
Data InterpretationRecommendationsRecommendations
Conduct on-going, long-term detection limit Conduct on-going, long-term detection limit studies rather than one-time studies; studies rather than one-time studies;
Confirm all water quality exceedances with Confirm all water quality exceedances with a separate analysis;a separate analysis;
Use multiple method blanks with each Use multiple method blanks with each analytical preparation batch;analytical preparation batch;
Use rigorous quality control measures to Use rigorous quality control measures to ensure data integrity;ensure data integrity;
