Measuring PCBs in Lake Ontario Surface Water Using Full-Scan Congener Methods

Transcription

1 Measuring PCBs in Lake Ontario Surface Water Using Full-Scan Congener Methods Implications for designing environmental assessment programs Frederick Luckey U.S. Environmental Protection Agency, Region 2 Simon Litten New York State Dept. of Environmental Conservation Brian Fowler AXYS Analytical Services (Currently with Waters)

2 Objectives Support the information needs of the Lake Ontario Lakewide Management Plan by measuring surface water concentrations of: PCBs Pesticides Dioxins / Furans Mercury PBDEs Identify contaminants exceeding water quality criteria.

3 Polychlorinated Biphenyl (PCB) Terminology Congener One of 209 possible configurations of the number and position of chlorines on the two phenyl rings. Homolog Set of congeners having the same number of chlorines / molecular weight. 10 PCB Homolog Groups Mono- chlorinated biphenyl Di - chlorinated biphenyl Tri- chlorinated biphenyl Tetra - chlorinated biphenyl Penta - chlorinated biphenyl Hexa- chlorinated biphenyl Hepta- chlorinated biphenyl Octa- chlorinated biphenyl Nona- chlorinated biphenyl Deca - chlorinated biphenyl 1 Chlorine 2 Chlorines 3 Chlorines 4 Chlorines 5 Chlorines 6 Chlorines 7 Chlorines 8 Chlorines 9 Chlorines 10 Chlorines

4 Polychlorinated Biphenyl (PCB) Terminology Using Homologs to Simplify Us= Data Analysis Commercial PCB Formulation: Aroclor 1248 % Total PCB mono di tri tetra penta hexa hepta octa nona deca PCB Homolog Group

5 Polychlorinated Biphenyl (PCB) Terminology ,2,4,4 - tetrachlorobiphenyl IUPAC # PCB- 47

6 Great Lakes Basin

7 Lake Ontario Open Water Sampling Fall 1999 Spatially, temporally integrated large volume water samples 24 hour continuous sampling Sampled from ~1 m depth Sampling in water depths >75 m

8 Lake Ontario Surface Water Large Volume Sampling Western / Central / Eastern Basin Sampling Grids Research Vessel Lake Guardian EPA Great Lakes National Program Office Province of Ontario New York State

9 Total Organics Platform Sampler (TOPS) Large Volume Sampler capture any break thru XAD Resin #2 Lake capture dissolved XAD Resin #1 capture solids Glass Fiber Cartridge Filter 1 um filter out large zooplankton & debris Nytex Netting Surface Water Intake ~I m deep

10 Lake Ontario Surface Water Large Volume Sampling XAD Resin Columns 35 grams each Dissolved Phase flow rate ml / min sample volumes ~800 L Glass Fiber Cartridge Filters 2.5 diameter x 4 Solids Phase flow rate 3 L / min 1 micron nominal pore size sample volumes ~5000 L

11 Calculating PCB Water Concentrations PCB mass (picograms) TOPS Sample Volume (L) = Water Conc. (pg/l) Sample Specific Detection Limit is inversely proportional to Sample Volume

12 CB Analytical Method EPA Method 1668A High resolution gas chromatography & mass spectrometry Solvent extracted & cleaned with liquid chromatography Samples spiked with 13 C 12 -labelled PCB congeners Selected ion method EI mode at 10,000 resolution Identifies 160 congeners / coeluting congener groups

13 Data Handling Data Handling Lab results corrected based on C 12 -labelled PCB congener surrogate recoveries Values <3X Lab or Field Blank Reject. Values >3X and <5X Lab or Field Blank Flag Non-detects = Zero

14 Lake Ontario Surface Water PCBs (pg/l) Western-2 Western-1 Eastern Solids Dissolved Central New York Water Quality Criteria Picograms/ Liter (parts per quadrillion)

15 Can You Believe These Numbers? Importance of Quality Control Field Sampling QA Checks XAD capture efficiency Suspended Solids capture efficiency Check on XAD wash-out effect - 13 C 12 PCB surrogates Duplicate Samples & Field Blanks Manual Check on Flow Meter Accuracy Lab QA Checks Samples spiked with internal 13 C 12 PCB surrogates Lab Blanks

16 XAD Resin Use of Washout Field Surrogates 13 C 12 -Labelled PCB-31, PCB-95 PCB C 12 -labelled PCB-153 Picogram / sample Spike Conc. Measured Conc Lab Blank Field Blank XAD #1 XAD #2 XAD #3 XAD #4 XAD #5

17 Lake Ontario Surface Water PCBs Raw pg/sample Field & Lab Blank Issues XAD XAD XAD XAD Filter Filter Filter Filter XAD Filter Blank Blank Blank Field Sample Lab Blank Field Blanks Picogram / sample

18 Lake Ontario Surface Water PCBs XAD Resin Field Blank Issues Field Blank Sample - 5 Sample - 4 Sample - 3 BZ-44 BZ-45 BZ-68 Sample - 2 Sample Picogram / sample

19 Checking XAD Field Extraction Efficiency ( Divinylbenzene-styrene copolymer resin ) Ideally all contaminants will be captured on 1 st XAD column XAD Column #1 XAD Column #2

20 XAD Resin Capture Efficiency Percent of Congeners Captured on First XAD Column 100% of congener mass captured on the first column Except for: PCB Congener IUPAC ID % Captured on 1st XAD Column

21 Duplicate Results Comparison of PCB Homolog Total Concentrations Pg / l Dissolved Phase XAD Resin West #1 8 West # Mono Di Tri Te tra Pe nta He x a He pta Octa Nona De ca Pg / l Solids Phase Glass Fiber Cartridge Filter West #1 West #2 Mono Di Tri Te tra Pe nta He x a He pta Octa Nona De ca PCB Homolog Group

22 Lake Ontario Total PCBs Homolog Percent Relative Abundance 30 % Total PCB Central Eastern Western #1 Western #2 0 Mono Di Tri Tetra Penta Hexa Hepta Octa Nona PCB Homolog Group

23 PCB Homolog Patterns in Field Blanks % Total PCB Filter XAD Mono Di Tri Tetra Penta Hexa Hepta Octa Nona Deca PCB Homolog Group

24 Lake Ontario Surface Water PCBs Suspended Solids 30 % Total PCB Central Eastern Western #1 Western #2 0 Mono Di Tri Tetra Penta Hexa Hepta Octa Nona Deca PCB Homolog Group

25 Average Lake Ontario Surface Water Total PCBs Congeners > 1% of Total PCBs PCB Congener IUPAC ID % of Total PCB

26 Lake Ontario Surface Water Total PCBs Fall 1999 Relative Abundance of Dominant PCB Congeners Penta Tetra Tri Eastern Central West #1 West #2 Di % of Total PCBs

27 Dominant Lake Ontario PCB Congeners and Commercial PCB Formulations PCB Congener IUPAC ID % of PCB Aroclor Mixture

28 Important Great Lakes Monitoring Programs Understanding Contaminant Sources & Loadings Niagara River Upstream- Downstream Monitoring Program International Atmospheric Deposition Network (IADN)

29 Sources of Lake Ontario PCB Loadings (Kg/Year) Net Change -283 Kg/Year Other Great Lakes Niagara R. Basin Lake Ontario Basin Tribs. Point Sources Atmospheric Deposition Atmospheric Volatiliz. St. Lawrence R. Outflows Kilograms Per Year

30 PCB Congeners Not Included in IADN & US/DS PCB Congener IUPAC ID PCB-11 IADN & US/DS PCB-1 IADN PCB-37 US/DS % of Lake Ontario Surface Water PCBs

31 PCB-11 in Selected Surface Waters Long Island Sound Lake Ontario Newark Bay Hudson River Dwnstrm Hudson River Upstrm PCB-11 as % Total PCB

32 Known Sources of PCB-11 Diarylide Yellow Pigment Manufacturing Associated with 3,3 -dichlorobenzidine salts Intermediates in the manufacture of diarylide yellow Loss of distal ammonia groups produces PCB-11

33 Designing Environmental Assessments Selecting a PCB Analytical Method Factors to Consider: Financial resources Available Analytical equipment / labs / staff Regulatory data requirements Historical data sets Expected levels of contamination / interferences Detection limit requirements

34 Recommendations for Designing PCB Surface Water Environmental Assessment Monitoring Strategies Use full-scan congener methods on some samples to ensure that all environmentally significant congeners are recognized. Ensure that detection limits are low enough to determine if water quality criteria are being met. Evaluate full-scan results to determine if selected analytical approach will adequately characterize target area.

35 Lake Ontario Surface Water PCBs 1999 Fall Total PCBs are ~ 40 pg/l in open waters > 90% of PCBs in dissolved phase Tri- & Tetrachlorobiphenyls dominant homologs Similar congener & homolog patterns across lake Dominant congener, PCB-11, not included in routine monitoring, unrelated to commercial PCB mixtures

36 Acknowledgemen ts Thanks for the support provided by: USEPA Great Lakes National Program Office Captain & Crew of the R/V Lake Guardian