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Case Study to Establish Background Soil
Concentrations of PCDD/Fs
Dioxin 2010 Conference – September 12, 2010
San Antonio,...
What are Polychlorinated dioxins
and Furans?
• Aromatic compounds with multiple chlorine
groups (1 to 8)
• 75 different co...
Sources of PCDD/Fs
• Not produced intentionally and no known uses
• Can be natural produced in forest fires and
volcanic a...
Ubiquitous
• Found in measurable
concentrations everywhere (in
remote areas)
• Local point sources contribute to
concentra...
ToXICITY
• Depending on jurisdiction,
group 1 carcinogen
• Toxicity based on binding to
Ah-receptor
• Effects mediated by ...
TEQs
• Each of the 17 congeners bind with different
affinity to the AhR
• The binding affinity is represented by the toxic...
Exposure to PCDD/Fs
• Humans predominantly exposed via diet (meat
and dairy)
• Incidental exposure – soil ingestion
• Inha...
What’s the issue?
www.chemistry-matters.com 8© 2015
Chemistry Matters Inc.
What’s the issue?
• CCME reevaluating guidelines (so is EPA)
• Current CCME guidelines are de minimus values based on
“bac...
What’s the issue?
• Canada has a very low screening level
– Likely due to large areas of uninhabited
areas which makes it ...
Additional issues
• PCDD/F analysis is very expensive ($500-1200)
• Establishing background is expensive
– What is conside...
Extreme Sensitivity
(2,3,7,8-TCDD)
Weight Moles Molecules
Microgram (10-6) 3 Nanomoles (10-9) 2,000,000,000,000,000
Nanogr...
One part-per-quadrillion
(ppq or ag/µL)
is like measuring
1 second in 1 x 1015 seconds
… or 1 second in 32,000,000 years
w...
Goals of Study
• Evaluate true background PCDD/F
concentrations in Alberta
– True background – away from roads, known
sour...
Methodology
• Advantageous sampling
• Cleaning sampling
equipment
• QA-QC samples
• Temperature monitoring
• Data review
•...
Study Summary
• 36 samples from around
southern Alberta
• Locations were chosen
based on :
– advantageous
sampling
– land ...
Locations
• Sundre
• Cochrane
• Airdrie
• Strathmore
• Okotoks
• Brooks
• Medicine
Hat
www.chemistry-matters.com 17© 2015
...
Sampling Locations
www.chemistry-matters.com 18© 2015
Chemistry Matters Inc.
Hiccup
• Lab sub-sampled 10 grams of soil for analysis (as
per EPA protocol)
• Detection limits cause artificially high TE...
Results
Concentration (pg/g TEQ)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
2
6
10
14
18
22
No.ofobs.
Max
0.61
Min
0.027
Mean
0.13
n=...
Results
Guideline – 4 pg/g TEQ
Log normalized data
• Better shows distribution of log normal data
0.025 0.04 0.06 0.10 0.1...
Dioxin Patterns
• Dioxin patterns can be preserved even at low
concentrations
• Creosote/PCP site showing patterns at diff...
Dioxin Patterns
0.1
1
10
100
PCP/Creosote
0.1
1
10
100
Urban Dust
0.1
1
10
100
Burn Barrel
0.1
1
10
100
Diesel Exhaust
0.1...
Summary
• Background (true background)
concentrations of PCDD/Fs in
southern AB are well below 4
pptr TEQ.
• Forensics can...
Q u e s t i o n s ?
www.chemistry-matters.com 25© 2015
Chemistry Matters Inc.
Contact Info:
Chemistry Matters Inc.
Court Sandau
Cell: 1.403.669.8566
Email: csandau@chemistry-matters.com
URL: chemistry...
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Background soil dioxins 2010 San Antonio Dioxin Conference

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Soil dioxin concentrations in southern Alberta investigation presented at the San Antonio Dioxin 2010 conference. Examined concentrations and fingerprints of chlorinated dioxins and furans (PCDD/Fs) in soils sampled in rural areas in southern Alberta.

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Background soil dioxins 2010 San Antonio Dioxin Conference

  1. 1. Case Study to Establish Background Soil Concentrations of PCDD/Fs Dioxin 2010 Conference – September 12, 2010 San Antonio, Texas Presented By: Court D. Sandau, PhD, PChem: © 2015 Chemistry Matters Inc.
  2. 2. What are Polychlorinated dioxins and Furans? • Aromatic compounds with multiple chlorine groups (1 to 8) • 75 different congeners – “Dioxins”, PCDDs • 135 different congeners – “Furans”, PCDFs O O H Cl Cl H H Cl Cl H 1 2 3 4 9 6 8 7 O H Cl Cl H H Cl Cl H 6 8 9 4 1 3 2 7 www.chemistry-matters.com 2© 2015 Chemistry Matters Inc.
  3. 3. Sources of PCDD/Fs • Not produced intentionally and no known uses • Can be natural produced in forest fires and volcanic activity • By-products of combustion when chlorine is present (e.g. medical or municipal waste incineration, barrel burning, diesel) • By-products during chemical manufacturing (e.g. PCP, 2,4,5-T, PCBs, etc.) • By-products of industrial process (e.g. steel mills, coal combustion, wood treatment, etc.) • Pulp and paper bleaching process – historically a major source www.chemistry-matters.com 3© 2015 Chemistry Matters Inc.
  4. 4. Ubiquitous • Found in measurable concentrations everywhere (in remote areas) • Local point sources contribute to concentrations • Redistribution and deposition via atmospheric transport • Concentrations vary dramatically in the environment www.chemistry-matters.com 4© 2015 Chemistry Matters Inc.
  5. 5. ToXICITY • Depending on jurisdiction, group 1 carcinogen • Toxicity based on binding to Ah-receptor • Effects mediated by a receptor binding mechanism • Only 2,3,7,8 chlorine containing congeners bind with AhR • Therefore, 17 congeners measured routinely • 2,3,7,8-TCDD binds with highest affinity www.chemistry-matters.com 5© 2015 Chemistry Matters Inc.
  6. 6. TEQs • Each of the 17 congeners bind with different affinity to the AhR • The binding affinity is represented by the toxic equivalency factor for that congener (TEF) relative to the 2,3,7,8-TCDD affinity (given a value of 1) • Each congener concentration multiplied by TEF then summed to get total TEQ of the sample • Latest TEFs – from WHO 2005 reassessment • What about NDs? – ½ DL is usual procedure www.chemistry-matters.com 6© 2015 Chemistry Matters Inc.
  7. 7. Exposure to PCDD/Fs • Humans predominantly exposed via diet (meat and dairy) • Incidental exposure – soil ingestion • Inhalation – particulates (not vapours) www.chemistry-matters.com 7© 2015 Chemistry Matters Inc.
  8. 8. What’s the issue? www.chemistry-matters.com 8© 2015 Chemistry Matters Inc.
  9. 9. What’s the issue? • CCME reevaluating guidelines (so is EPA) • Current CCME guidelines are de minimus values based on “background” concentrations from studies in Canada (1990s) 10 4 1 10 #N/A #N/A #N/A 250 #N/A #N/A 10 100 #N/A 500 100 #N/A 1,000 10 1,000 360 1,500 #N/A #N/A #N/A 10,000 1,500 #N/A 10,000 100 1,000 #N/A 18,000 #N/A 1 10 100 1000 10000 100000 Austria Canada CzechRepublic Finland France Germany Italy Japan Netherlands NewZealand Sweden SoilLevel(ppt) Screening Level Res Action Level Comm/Ind Action Level US EPA – Review of International Soil Levels for Dioxin, 2009 International Screening Levels and Action Levels www.chemistry-matters.com 9© 2015 Chemistry Matters Inc.
  10. 10. What’s the issue? • Canada has a very low screening level – Likely due to large areas of uninhabited areas which makes it difficult to establish background level – This is eluded to in the CCME guidance • Background concentrations vary for locations • Therefore, what is background? – Where concentrations drop below 4 pg/g TEQ? – Certain distance away from local source? – No distinctive signature? www.chemistry-matters.com 10© 2015 Chemistry Matters Inc.
  11. 11. Additional issues • PCDD/F analysis is very expensive ($500-1200) • Establishing background is expensive – What is considered background? • Non-detects cause other issues (see later slide) • Levels measured are very low – Scientific notation for ppt is 1x10-12 – For reference: • ppt is equal to pg/g (solids) and ng/L (solutions) • Watch for cross contamination www.chemistry-matters.com 11© 2015 Chemistry Matters Inc.
  12. 12. Extreme Sensitivity (2,3,7,8-TCDD) Weight Moles Molecules Microgram (10-6) 3 Nanomoles (10-9) 2,000,000,000,000,000 Nanogram (10-9) 3 Picomoles (10-12) 2,000,000,000,000 Picogram (10-12) 3 Femtomoles (10-15) 2,000,000,000 Femtogram (10-15) 3 Attomoles (10-18) 2,000,000 Attogram (10-18) 3 Zeptomoles (10-21) 2,000 Zeptogram (10-21) 3 Yaktomoles (10-24) 2 Yaktogram (10-24) 3 Fantomoles (10-27) 0.002 Currently at the attogram level with high resolution mass spectrometry www.chemistry-matters.com 12 © 2015 Chemistry Matters Inc.
  13. 13. One part-per-quadrillion (ppq or ag/µL) is like measuring 1 second in 1 x 1015 seconds … or 1 second in 32,000,000 years www.chemistry-matters.com 13 © 2015 Chemistry Matters Inc.
  14. 14. Goals of Study • Evaluate true background PCDD/F concentrations in Alberta – True background – away from roads, known sources, atmospheric collection areas (i.e. trees, buildings) • Examine patterns of PCDD/Fs in background samples www.chemistry-matters.com 14© 2015 Chemistry Matters Inc.
  15. 15. Methodology • Advantageous sampling • Cleaning sampling equipment • QA-QC samples • Temperature monitoring • Data review • Detection limit assessment T09-123-S1 Sample Temperatures -30 -20 -10 0 10 20 30 40 507/16/09 12:00 AM 7/18/09 12:00 AM 7/20/09 12:00 AM 7/22/09 12:00 AM 7/24/09 12:00 AM 7/26/09 12:00 AM 7/28/09 12:00 AM 7/30/09 12:00 AM 8/1/09 12:00 AM Time Temperature(°C) Samples placed in cooler Samples removed from freezer Samples placed in freezer Samples removed from cooler www.chemistry-matters.com 15© 2015 Chemistry Matters Inc.
  16. 16. Study Summary • 36 samples from around southern Alberta • Locations were chosen based on : – advantageous sampling – land access public lands (or known land owners) – undisturbed – no known sources – away from major roads www.chemistry-matters.com 16© 2015 Chemistry Matters Inc.
  17. 17. Locations • Sundre • Cochrane • Airdrie • Strathmore • Okotoks • Brooks • Medicine Hat www.chemistry-matters.com 17© 2015 Chemistry Matters Inc.
  18. 18. Sampling Locations www.chemistry-matters.com 18© 2015 Chemistry Matters Inc.
  19. 19. Hiccup • Lab sub-sampled 10 grams of soil for analysis (as per EPA protocol) • Detection limits cause artificially high TEQs Sample ID TEQ (pg/g) % TEQ from NDs 10g 100g 10g 100g 002 0.155 0.177 42% 23% 003 0.070 0.038 92% 71% 005 0.091 0.062 72% 56% 029 0.334 0.040 99% 95% 030 0.213 0.042 100% 100% 035 0.158 0.105 54% 13% • Increased sub-sample to 100 g • TEQ less dependent on DLs, more representative of measured congeners • DLs decrease with increased sample size – TEQ 30% lower for 16 samples analyzed that were 100 g www.chemistry-matters.com 19© 2015 Chemistry Matters Inc.
  20. 20. Results Concentration (pg/g TEQ) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 2 6 10 14 18 22 No.ofobs. Max 0.61 Min 0.027 Mean 0.13 n=36 Guideline – 4 pg/g TEQ www.chemistry-matters.com 20© 2015 Chemistry Matters Inc.
  21. 21. Results Guideline – 4 pg/g TEQ Log normalized data • Better shows distribution of log normal data 0.025 0.04 0.06 0.10 0.16 0.25 0.40 0.63 0 2 4 6 8 10 12 14 No.ofobs. Concentration (pg/g TEQ) Max 0.61 Min 0.027 Mean 0.13 n=36Geomean 0.090 95% UCL 0.17 www.chemistry-matters.com 21© 2015 Chemistry Matters Inc.
  22. 22. Dioxin Patterns • Dioxin patterns can be preserved even at low concentrations • Creosote/PCP site showing patterns at different orders of magnitude concentrations • 2378 normalized homologues 0.1 1 10 100 0.1 1 10 100 0.1 1 10 100 Concentration TEQ – 350 pg/g TEQ – 30 pg/g TEQ – 2 pg/g www.chemistry-matters.com 22© 2015 Chemistry Matters Inc.
  23. 23. Dioxin Patterns 0.1 1 10 100 PCP/Creosote 0.1 1 10 100 Urban Dust 0.1 1 10 100 Burn Barrel 0.1 1 10 100 Diesel Exhaust 0.1 1 10 100 Crematorium 0.1 1 10 100 Alberta Background ConcentrationConcentration TEQ 0.61 www.chemistry-matters.com 23© 2015 Chemistry Matters Inc.
  24. 24. Summary • Background (true background) concentrations of PCDD/Fs in southern AB are well below 4 pptr TEQ. • Forensics can be used to determine local background pattern • DLs can play major role in data interpretation – watch % contribution • Need a health based guideline to use for site screening as “background” is ambiguous www.chemistry-matters.com 24© 2015 Chemistry Matters Inc.
  25. 25. Q u e s t i o n s ? www.chemistry-matters.com 25© 2015 Chemistry Matters Inc.
  26. 26. Contact Info: Chemistry Matters Inc. Court Sandau Cell: 1.403.669.8566 Email: csandau@chemistry-matters.com URL: chemistry-matters.com Twitter: @Chem_Matters Slideshare: www.slideshare.net/csandau © 2015 Chemistry Matters Inc.

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