180 likes | 340 Views
Biomonitoring II EnviroChem Connections. Mini-Talk 1 on CDC’s 3rd Report Suzanne Snedeker Cornell University Sprecher Institute for Comparative Cancer Research. Biomonitoring. What is biomonitoring? The direct measurement of chemicals or metabolites in humans
E N D
Biomonitoring IIEnviroChem Connections Mini-Talk 1 on CDC’s 3rd Report Suzanne Snedeker Cornell University Sprecher Institute for Comparative Cancer Research
Biomonitoring What is biomonitoring? • The direct measurement of chemicals or metabolites in humans • Reflects “internal dose” - what the body has actually taken up • Reflects all sources of exposure
Biomonitoring Source of Samples • Blood(whole or serum) • Urine(for chemicals rapidly excreted) • Adipose tissue (fat) • Breast milk • Toenails or hair • Exhaled breath
CDC 3rd Report - NHANES National Health and Nutrition Examination Survey (NHANES) • Done every 2 years by the CDC • Surveys 5,000 people in the U.S. • Home interview • Physical examination in “mobile unit” • Obtain blood sample (over 1 year) • Obtain urine sample (over 6 years) • Analysis done on a random sample
CDC 3rd Report-Scope of study design • 148 chemicals or their metabolites • Three age ranges: • 6-11 years, 12-19 years, 20-59 years • 1-5 years for some chemicals [lead] • Three ethnic / racial groups • Mexican Americans • Non-Hispanic Blacks • Non-Hispanic Whites
Types of chemicals • Metals • Organochlorine insecticides • Organophosphate insecticides • Pyrethroid Pesticides • Herbicides • Tobacco smoke (cotinine)
Types of Chemicals • Phthalates • Phytoestrogens • PAHs (polyaromatic hydrocarbons) • PCBs (polychlorinated biphenyls) • PCDDs (polychlorinated dibenzo-p-dioxins) • PCDFs (polychlorinated dibenzofurans)
Environmental Public Health Tracking - What it can provide • Direct assay of chemical body burden from all sources of exposure • Tracks trends in exposures over time • Identifies at-risk populations • Establishes “reference ranges” for chemicals for which we have little/no data • Helps evaluate if prevention efforts work • Provides direction for further research and monitoring efforts
Major findings - New data • First-time exposure data for 38 chemicals - “reference ranges” • Aldrin, endrin, and dieldrin • Some PAHs (benzo[a]pyrene) • Additional phthalate metabolites • Additional dioxins, furans and PCBs • Additional insecticides and herbicides Photo:www.cdc.gov/nceh/dls/national_biomonitoring_program.htm
Major findings - Blood Lead • Blood lead levels continue to decline • There is no “safe” level of blood lead • Percentage of children 1-5 years old with blood lead levels at or above 10 ug/dl • 1976-1980 88.2% • 1988-1991 8.6% • 1991-1994 4.4% • 1999-2002 1.6% Photos: www.cdc.gov/nceh/dls/lead.htm
Major findings-Urinary Cadmium (Cd) • 5% of US population has levels above 1 g Cd/g creatinine (? kidney effects ?) • Significance of Cd findings for breast cancer risk is not known, but provides much needed exposure data. • Cd can support the growth of breast tumor cell lines; may affect mammary development (lab animal studies)
Major findings - Phthalates • Phthalate metabolites • New, more sensitive biomarkers • Data on exposure at different ages • For most phthalate metabolites, levels in the urine of children 6-11 years of age were higher than levels in adults (sometimes twice as high) • Levels in US population at or higher than levels reported in Germany
Major findings -Organochlorine pesticides • p,p’-DDE • Levels in Mexican Americans • Two-fold high than non-Hispanic blacks • Three-fold higher in non-Hispanic whites • Other organochlorines • Many were below the limits of detection • Including: DDT, aldrin, endrin, dieldrin, heptachlor epoxide, mirex)
Major findings - Smoking • Environmental tobacco smoke • Dramatic decrease in exposure to environmental tobacco smoke in non-smokers (median cotinine levels) • Compared to 1988-91 data, saw: • 68% decrease in children • 69% decrease in adolescents • 75% decrease in adults Photo: www.cdc.gov/nceh/dls/tobacco_smoking.htm
New chemicals to be monitored in future reports • Metals (arsenic and methyl mercury) • Volatile Organic Chemicals (VOCs) • Polybrominated compounds • Phenols (bisphenol A, nonylphenol and octylphenol – estrogen mimics) • Perfluorinated compounds • Polychlorinated biphenyls (PCBs)
New chemicals to be monitored in future reports Additional pesticides in these classes • Organochlorine pesticides • Organophosphate pesticides • Chloroacetanilide herbicides • Acetochlor and metolachlor metabolites • Pyrethrins Photo: www.cdc.gov/biomonitoring/overview.htm
What the current CDC report does not provide • Levels by region (state, county, zip code) • Seasonal variations in levels • Environmental levels (air, water, food, soil) • Duration or intensity of exposures • Use of particular products • Whether levels are associated with a particular health effect
CDC - Spokes in the wheelEnvironmental Public Health Tracking • Biomonitoring program • Provides state funding • Targeted research projects • Improve infrastructure to integrate biomonitoring and health indicator data • Develops new biomarkers • Provides sample analysis for breast cancer studies