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 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
Predicting levels of toxicants in people using environmental monitoring is very difficult and includes many assumptions
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)
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.
Exposure Study on Biomass Burning – a Challenge Large emissions Numerous classes and uncountable chemicals released in biomass fires Particles and aerosols with organic compounds condensed on the surface can be transported over long distance
Emissions From Biomass Burning
Potential Markers for Biomass Burning -- Methoxyphenols Softwood guaiacyl compds Hardwood syringyl compds A urinary assay of methoxyphenols for biomonitoring wood smoke exposure has been developed
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 - 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
Identification of Unknowns -- GC x GC/TOFMS 4-Dimensional GC x GC-TOFMS Improving resolution, reducing chromatographic co-elution – more accurate analyte identifications Ideal for obtaining maximum information from complex samples
GC x GC/TOFMS
GC x GC/TOFMS
Quantitation – GC/HRMS
Objectives - Verify and confirm reported markers
- Search for new ones
Identify optimal metabolites in human body for biomonitoring 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. Exposure study on large scale agricultural burning, e.g. sugarcane burning in Brazil and Costa Rica
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