Presentation on theme: "Dioxins and Related Persistent Organic Pollutants (POPs) Arnold Schecter, MD, MPH Professor, Division of Environmental and Occupational Health Sciences,"— Presentation transcript:
Dioxins and Related Persistent Organic Pollutants (POPs) Arnold Schecter, MD, MPH Professor, Division of Environmental and Occupational Health Sciences, University of Texas School of Public Health, Dallas, TX, USA Vietnam July 26-30,2010 Email: email@example.com
3 Introduction Dioxins are in all humans. Elevated dioxins can persist in people 35+ years. Patterns of dioxins varies by source: – Paper and pulp bleaching: TCDF and TCDD. – Agent Orange: 2,3,7,8-TCDD. – Pentachlorophenol: 5-8 Cl PCDD/PCDF. – Incineration: All congeners, especially OCDD. – PCB transformer fires: PCDFs predominate.
4 Introduction (cont.) Toxicity of dioxins understood by: – Toxicology – in vivo animal studies. – Toxicology – in vitro mechanistic studies. – Human epidemiology “Safe” exposure level: – US EPA: 0.01 pg TEQ/kg BW per day x 70 yrs. – World Health Organization: 1 - 4 pg/kg BW per day x 70 yrs.
8 Known Dioxin Sources (cont.) Smelters (e.g., Aluminum and Copper) Paper and Pulp Bleaching with Chlorine Reservoir Sources (e.g., Sediment; Soil) Cement kilns Other
Agent Orange Agent Orange: Sprayed in Vietnam 1962-1971 – Spraying stopped due to science but mostly public outcry Agent Orange was half 2,4-D and half 2,4,5-T 2,4,5-T phenoxyherbicide contaminated with 2,3,7,8-TCDD (the most toxic dioxin) Spraying was in parts of southern Vietnam only
Ranch Hand Herbicide Spraying Missions Red Area Indicates Sprayed Areas
History of Dioxin Exposure Determination The Beginning: Harvard University Research in the 1970’s: – Baughman, Meselson, Constable – Most toxic dioxin found in very high levels in: – Vietnamese nursing mothers’ milk (1345, now 1.0 parts per trillion, lipid) – Vietnamese fish from sprayed area – Not detected in US nursing mothers’ milk – US fish were not studied
Vietnam/US Agent Orange History 1983-92: Agent Orange Conferences (Vietnam) 1984-2010: J. Constable & A. Schecter with the 10-80 Committee, Vietnam Red Cross and Committee 33
Worldwide Research Dioxin can cause: – Cancer – Immune deficiency – Nervous system problems – Reproductive problems – Developmental problems
Vietnam and U.S. Human Milk Dioxin (TCDD) Levels- 1970-80’s 1 Baughman RW. Tetracholodibenzo-p-dioxins in the environment: high resolution mass spectrometry at the pictogram level. Cambridge, MA: Harvard University; 1974. PhD thesis. 2 Olie K, Schecter A, Constable JD, Kooke RMM, Serné P, Slot PC, deVries P. Chemosphere. 1989; 19(1-6): 493-496. 3 Schecter A, Dai LC, Thuy LTB, Quynh HT, Minh DQ, Cau HD, Phiet PH, Phuong NTN, Constable JD, Baughman R, Päpke O, Ryan JJ, Fürst P, Räisänen S. American Journal of Public Health. 1995;85(4):516-522.
2,3,7,8 TCDD levels in Vietnamese fish, crustaceans, and U.S. imported Vietnamese food 1 Baughman RW, Meselson M. Environ Health Perspect. 1973;5:27-35. 2 Schecter A, Pavuk M, Malisch R, Ryan JJ. Journal of Toxicology and Env. Health. 2003;66(15), 1391-404
2,3,7,8 TCDD and Dioxin Toxic Equivalents (TEQ) (lipid, ppt) in Vietnamese Pooled Blood Collected 1991-92 Schecter A, Dai LC, Thuy LTB, Quynh HT, Minh DQ, Cau HD, Phiet PH, Phuong NTN, Constable JD, Baughman R, Päpke O, Ryan JJ, Fürst P, Räisänen S. American Journal of Public Health. 1995;85(4):516-522.
TCDD and TEQ in Food From Bien Hoa, 2003 ( ppt ww ) *Channa Striatta (snakehead) Schecter AJ et al. J Occup Environ Med. 2003; 45:781-788
Recent TCDD TEQ from Bien Hoa City and Aluoi Valley ‘hot spots’ (ppt) 1. Dwernychuk L, et al. Chemosphere 2002. 47:117-137. 2 Schecter A et al. J Occup Environ Med. 2003; 45:781-788. *EU Maximum Level 4 ppt (lipid) ** EU Max Level 8 ppt (ww) *** EU Max Level 1.5 ppt (lipid)
Recent Dioxin concentrations (>90% TEQ 2,3,7,8-TCDD) in soil and lake sediment at three airport “dioxin hotspots” 1. Son LK, Sau TK, Lanh DN, Net NX, Truong NX, Minh NV, Tam TN. Organohalogen Compounds. 2007; 69:881-883. 2. Hoai, DX, Tam, TN 2009 Organohalogen Compounds 71, 85-87
Da Nang Airbase 1 (2009) High TCDD levels in localized areas: – Soil up to 365,000 ppt TEQ – Sediment up to 6,270 ppt TEQ – Fish up to 3,000 – Vegetables up to 2,174 However, newest data is not public. 1. Le Thi Haoi 2009 Organohalogen Compounds. Dioxin 2009
Remediation Da Nang Airbase (2008) $ Ford Foundation + USEPA + US Congress Progress: – Construction of integrated facilities: Preventing infiltration and land erosion Monitoring Special filtration systems New reservoir and overflow dam Warnings and bans in contaminated areas Canh, P.N. Organohalogen Compounds, Volume 70, 2008, 547-549.
Bien Hoa City Residents (2008) Knowledge of dioxins is limited Unaware of routes of exposure Little concern for health impacts of dioxins Few are taking preventive measures 65.5 % of people surveyed did not care or did not know the sources of foods that they consumed daily. Le Vu Anh et al. Organohalogen Compounds Volume 70, 2008, 535-538.
Pesticides, PCDFs, and PCBs in Vietnam: Milk and Food (ppt ww) α-HCH (α-hexachlorocyclohexane) β-HCH (β-hexachlorocyclohexane) γ-HCH (γ-hexachlorocyclohexane or lindane) Hexachlorobenzene DDT DDT metabolites PCBs Dibenzofurans Schecter AJ et al. J Occup Environ Med. 2003; 45:781-788. Shelepchikov, AA et al. Organohalogen Compounds 2009; 71, 538-543
Long Term Remediation Technologies for Dioxin Contamination After Fong VS, Coakley W, Farland W, Tien NQ, Ha DTC, L PH, Minh DV, Portier C, Brown D, Ball G, Killeen D, Sweeney MH, Son LK, Duong NN. Organohalogen Compounds. 2007; 69:898-901.
Seveso TCDD Site at Present http://www.legambienteseveso.org/html/circolo/Foto/sito.jpg
Current Vietnam/US Collaboration – Da Nang Vietnam Ministry of National Defense, and Office of National Steering Committee 33, Hatfield Group, Ford Foundation Assess environmental contamination and effectiveness of current mitigation efforts Measure bio-accumulation of dioxin in the food chain and in people Enhance awareness, government management, scientific exchange
University of Texas Agent Orange and TCDD Research US Vietnam Veterans, Agent Orange Sprayer Ranch Hands – TCDD alters human thyroid axis 1 – TCDD associated with prostate and skin cancers 2 – TCDD associated with lower incidence rates of benign prostate hyperplasia (BPH) – TCDD found in semen could suggest a possible mechanism for male-mediated adverse reproductive 3 1 Pavuk M, Schecter AJ, Akhtar FZ, Michalek JE. Ann Epidemiol. 2003 May;13(5):335-43; 2 Pavuk M, Michalek JE, Schecter A, Ketchum NS, Akhtar FZ, Fox KA. J Occup Environ Med. 2005 Apr;47(4):335-42; 3 Schecter A, McCee H, Stanley J, Boggess K, Brandt-Rauf P. AJIM. 1996 (30):647-654.
Other US TCDD Research Findings WHO IARC: TCDD is a human carcinogen 1 WHO IARC: TCDD associated with multiple human pathologies 1 National Toxicology Program: TCDD is a human carcinogen 2 US EPA: Dioxin is a human carcinogen 3 US EPA: Dioxin causes multiple human effects 3 1 WHO IARC Monograph 69, PCDD/F, 1997 ; 2 NTP. 9th Report of Carcinogens. 2000, Rev. 2001; 3 US EPA Draft Dioxin Reassessment. http://www.epa.gov/ncea/pdfs/dioxin/nas-review/
Sufficient Evidence of Association A. Soft-tissue sarcoma (including heart) B. Non-Hodgkin’s lymphoma C. Chronic lymphocytic Leukemia (CLL) (including B cell leukemias, such as hairy cell leukemia) D. Hodgkin’s Disease E. Chloracne (US) “Veterans and Agent Orange, Update 2009” Institute of Medicine (IOM) US National Academy of Sciences (NAS)
Veterans and Agent Orange Update 2009, IOM/NAS (Continued) Limited Evidence of Association A. Laryngeal cancer B. Cancer of the lung, bronchus or trachea C. Prostate cancer D. Multiple myeloma E. Light Chain (AL) amyloidosis F. Early-onset transient peripheral neuropathy
Veterans and Agent Orange Update 2009, IOM/NAS (Continued) Limited Evidence of Association G. Parkinson’s disease H. Porphyria cutanea tarda I. Hypertension J. Ischemic heart disease K. Type 2 diabetes (mellitus) L. Spina bifida in offpsring of exposed people
Current Vietnam Activities (?) Remediation- planning and implementation Assistance to “Agent Orange Victims” Education of the public, exposed and others Agent Orange health research Agent Orange remediation research Agent Orange environmental research Scientific publications and presentations Government to Government cooperation
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