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03_Li_CDC_Biomonitoring

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									   Biomonitoring of Human
Exposure to Biomass Burning
 -- A Proposed Collaboration
        with GA Tech
  Zheng (Jane) Li, Courtney D Sandau
  PAH and Combustion Exposure Biomarker Section
       Organic Analytical Toxicology Branch
          Division of Laboratory Sciences
     National Center for Environmental Health
    Centers for Disease Control and Prevention
                 Atlanta, GA 30341
What is Biomarker?

      Biomarkers of exposure refer to
cellular, biochemical, analytical, or
molecular measures that are obtained from
biological media such as tissues, cells, or
fluids and are indicative of exposure to an
agent.
What is Biomonitoring?

     Assessment of internal dose exposure
by measuring a toxicant, or its metabolite
or reaction product (biomarker) in human
blood, urine, saliva, adipose, or other tissue
Exposure and health effects pathway
        Location: nearness to source

      External dose: air, water, food, soil

                     inhalation
                     ingestion                   Exposure
                     skin absorption             assessment

    Internal dose: blood, serum, urine, tissue


    Biologically effective dose: blood, tissue
                                                 Health effects
              Health effect                      assessment
Predicting levels of toxicants in people using environmental monitoring
is very difficult and includes many assumptions




                                         Air levels   Instead of predicting,
                          Water levels
                                                      we measure levels of
              Soil/dust levels
                                                      chemicals in people
            Food levels

     Nutritional status
                                                              Predicted
                                    Mathematical
     Lifestyle factors
                                     Modeling
                                                          levels of toxicants
      Personal habits                                         in people
        Genetic factors

    Lung, intestine and skin
     absorption coefficients

                                MANY OTHER FACTORS
Biomonitoring provides unique
information for --

• The public health response to a known or
    suspected excessive exposure to a toxicant(s) or
    a pollutant(s).
•   Health research to determine what toxicants and
    what internal dose levels cause disease or death
•   Human data significantly decrease uncertainty in
    assessing human risk
                    National Report on Human
                    Exposure to Environmental
                    Chemicals (NHANES)

                    http://www.cdc.gov/exposurereport

                                      2003 – 2nd NHANES report
                                            116 Chemicals

                                      14 OH-PAHs:
                                      1-OH-pyrene
                                      3-OH-fluoranthene
      2001                            2/3-OH-fluorene
                                      1/2/3-OH-phenanthrene
1st NHANES report                     3/6-OH chrysene
     released                         1/3-OH-benz[a]anthracene
                                      1/2/3-OH-benzo[c]
  27 chemicals                        phenanthrene
PAH & Combustion Exposure Biomarker
Laboratory

• CDC currently monitors Group A (2-4 aromatic ring)
    PAH-OH metabolites, conducted in our laboratory
•   Newly developed method has LOD for most of 23 OH-
    PAHs at low ppt
•   Expanding to include metabolites of Group B (5 and
    more aromatic ring, e.g. OH-benzo[a]pyrene), and
    amino-PAHs, metabolites of NO2-PAH.
•   Initializing and developing methods to monitor human
    exposure to biomass burning
Exposure Study on Biomass
Burning – a Challenge
• Large emissions
• Numerous classes and uncountable chemicals
    released in biomass fires
•   Various emission profiles from different
    burning sources
•   Particles and aerosols with organic compounds
    condensed on the surface can be transported
    over long distance
Emissions From Biomass Burning
                                         CO, NOX, SO2, O3
                Particulate Matter



      Resin acids                                  PAHs and alkyl PAHs




  Anhydrosugars,
 e.g. levoglucosan                                     PCDD and PCDF



Alkyl amides and nitriles                   Many others…

                        Methoxyphenols
Potential Markers for Biomass
Burning -- Methoxyphenols
• One major group of compounds studied as
    biomarkers            R


•   Softwood                       OCH3
                                             guaiacyl compds
                          OH
                               R


• Hardwood                            OCH3
                                             syringyl compds
                   H3CO
                               OH

• A urinary assay of methoxyphenols for
    biomonitoring wood smoke exposure has been
    developed
Potential Markers for Biomass
Burning -- PAHs
• A major group of organic pollutants formed
    during incomplete combustion
•   Mutagenic and carcinogenic
•   Most abundant ones are pyrene, phenanthrene,
    fluoranthene, benzo(a/e)pyrene, chrysene, etc.
•   Alkyl-PAHs, e.g. pimanthrene and retene,
    suggested to be the major source specific
    biomarkers in pine smoke
PAHs, Source-specific Markers

• Relative amounts of alkyl-PAHs to the parent
    PAHs – petrogenic source vs. combustion source
•   Relative amounts of unstable or kinetic PAHs to
    the more stable or thermodynamic PAHs –
    combustion or anthropogenic input
•   Acenaphthene and acenaphthylene – combustion
    source; cadalene and retene – plant source
Analytical Techniques

• Extraction
• Solid phase extraction (SPE) or silica/florisil
    column for further sample clean up
•   Gas chromatography/mass spectrometry
    – GC/Time-of-flight (TOF) MS
    – GC x GC/TOFMS
    – GC/high-resolution MS
• Isotope dilution for precise and accurate
    measurements
Identification of Unknown Markers
-- GC/TOFMS

                    2-fluo
                                                   19 OH-PAH mix
                 3-fluo
    1-nap



                                                     6 minutes     LECO Pegasus
   2-nap



                                                                   III

                     1-,2-,3-,4-,9-phen                            Fast GC/TOFMS
                                                                   Separation


                                          1-pyr
            9-fluo




                                                                   Full Scan
                                    3-flran                        Extensive library
                                    1-bcp

                                                                   search
                                                                   Unknown peak




                                                       3-chry
                                                                   identification



                                                      3-baa
                                                     1-baa
                                                     3-bcp
                                                  6-chry
                                                  2-bcp
                                                                   De-convolution
Identification of Unknowns -- GC x GC/TOFMS

• 4-Dimensional GC x GC-TOFMS
• Two distinctive separation mechanisms,
  such as polar and non-polar
• Improving resolution, reducing
  chromatographic co-elution – more
  accurate analyte identifications
• Ideal for obtaining maximum information
  from complex samples
GC x GC/TOFMS

                Contour plot

                 Mixture of
                58 compds:
                  37 PCBs
                   11 PPs
                    1 BB
                  8 BDEs



                 Courtesy slide
                from Jef Focant
GC x GC/TOFMS




   Contour plot                                    Shade surface plot


                  Courtesy slide from Jef Focant
Objectives
• Identify source-specific markers for biomass
  combustions
  – Verify and confirm reported markers
  – Search for new ones
• Identify optimal metabolites in human body for
  biomonitoring
  – Parent compounds or metabolites
  – Urine or blood
• Perform studies on populations exposed to
  biomass burning
Possible Population/Field Studies

• Exposure assessment to indoor air pollution
    caused by domestic biomass burning in
    developing countries, e.g. China, India, etc.
•   Occupational and residential exposure to forest
    fires
•   Exposure study on large scale agricultural
    burning, e.g. sugarcane burning in Brazil and
    Costa Rica

								
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