Toxicology Issues & Groundwater Toxicology Issues & Groundwater Remediation from Fuel Leaks Remediation from Fuel Leaks South Korean MTBE Clean Fuels Workshop South Korean MTBE Clean Fuels Workshop Grand Hilton Hotel Grand Hilton Hotel Seoul, South Korea Seoul, South Korea 3 November 2004 3 November 2004 John Kneiss John Kneiss Chief Consultant Chief Consultant Clean Transportation Advisory Council Clean Transportation Advisory Council 1
Presentation Outline Presentation Outline � Toxicology & Health Risk Issues Toxicology & Health Risk Issues � � Petrol Constituents of Concern Petrol Constituents of Concern � � Emissions Emissions � � Exposure Scenarios Exposure Scenarios � � Comparative Risk Analysis Comparative Risk Analysis � � Groundwater Remediation from Fuel Leaks Groundwater Remediation from Fuel Leaks � � Technologies/Processes for Removal Technologies/Processes for Removal � � Drinking Water Treatment Drinking Water Treatment � � Bioremediation & Natural Attenuation Bioremediation & Natural Attenuation � � MTBE & U.S. Situation MTBE & U.S. Situation � � Conclusions & Questions Conclusions & Questions � 2
Some Background About Toxicology � Toxicology defined as study of nature, effects and Toxicology defined as study of nature, effects and � detection of toxins and treatment of toxic exposures detection of toxins and treatment of toxic exposures � “Dose Makes the Poison” “Dose Makes the Poison” � � What Toxicology Studies Can’t Tell Us? What Toxicology Studies Can’t Tell Us? � � Toxicology Studies Toxicology Studies � � Animal Tests Animal Tests � � Genetic Tests Genetic Tests � � Human Volunteer Tests Human Volunteer Tests � � Epidemiology Epidemiology Studies Studies � � Exposure Studies Exposure Studies � � “Risk Assessment” Process “Risk Assessment” Process � 3
Toxicology – Often Misrepresented � Advances in study methods have expanded our Advances in study methods have expanded our � understanding of how substances interact with living understanding of how substances interact with living systems systems � “Dose Makes the Poison” “Dose Makes the Poison” � � At HIGH enough exposure, anything can be “toxic” At HIGH enough exposure, anything can be “toxic” � � Interactions (synergism) from exposure to complex Interactions (synergism) from exposure to complex � mixtures mixtures � What Toxicology Studies Can’t Tell Us? What Toxicology Studies Can’t Tell Us? � � Can’t prove something is “safe” Can’t prove something is “safe” � � Can’t demonstrate individual risk Can’t demonstrate individual risk � � Can show statistical correlation for effects Can show statistical correlation for effects � � Can be poor predictors for potential human risk Can be poor predictors for potential human risk � 4
Toxicological Studies – Animal Studies � Laboratory tests using control (unexposed) and Laboratory tests using control (unexposed) and � exposed animal groups exposed animal groups � Various exposure routes Various exposure routes – – oral, dermal, inhalation oral, dermal, inhalation – – to to � best mimic human exposure potential best mimic human exposure potential � Neurotoxicity Neurotoxicity studies studies � � Reproductive and developmental studies Reproductive and developmental studies � � Systemic effects studies Systemic effects studies � � Genetic assays Genetic assays � � Carcinogenicity Carcinogenicity studies studies � � Pharmacokinetics Pharmacokinetics – – How substances enter the body, How substances enter the body, � get distributed to tissues, become metabolized and get distributed to tissues, become metabolized and then eliminated (or retained) then eliminated (or retained) 5
Epidemiology Studies � Human volunteer studies Human volunteer studies � � Adapted from pharmaceutical methodology Adapted from pharmaceutical methodology � � Rarely conducted for industrial materials Rarely conducted for industrial materials � � Intended to help interpret findings from animal Intended to help interpret findings from animal � studies studies � Epidemiological studies Epidemiological studies – – investigations of effects in investigations of effects in � human populations human populations � Confounding factors complicate study designs & data Confounding factors complicate study designs & data � interpretations interpretations � Sub Sub- -populations populations – – unique exposure conditions unique exposure conditions � � Exposure studies Exposure studies – – collection of monitoring data collection of monitoring data � � Macro Macro- -environments environments � � Micro Micro- -environments environments � 6
Risk Assessment Process � Risk Assessment Risk Assessment – – Estimation of potential risk of Estimation of potential risk of � exposure AND management (mitigation) of that risk exposure AND management (mitigation) of that risk � Hazard characterization Hazard characterization – – classification schemes classification schemes � � Risk estimation Risk estimation – – statistical methods to quantify statistical methods to quantify � risk potential for particular exposures risk potential for particular exposures � Risk management Risk management – – defining and implementing defining and implementing � appropriate control measures appropriate control measures � Comparative Risk Assessment Comparative Risk Assessment – – evaluations to set evaluations to set � priorities for public health protection priorities for public health protection � Should have comparable data sets Should have comparable data sets � � Should be conducted without bias (objectivity) Should be conducted without bias (objectivity) � 7
Petrol Constituents of Concern Petrol Constituents of Concern � Petrol Petrol – – Complex Mixture of Hundreds of HC Compounds Complex Mixture of Hundreds of HC Compounds � � Non Non- -soluble fraction soluble fraction – – generally little concern generally little concern � � Aromatics Aromatics – – especially benzene especially benzene � � Olefins Olefins – – mainly air emissions from fuel combustion mainly air emissions from fuel combustion � � Oxygenates Oxygenates � � Fuel Fuel- -Ethanol Ethanol � � MTBE MTBE � � Other Ethers Other Ethers � � Additives, including octane enhancers, detergents, etc. Additives, including octane enhancers, detergents, etc. � � Extensive Studies on Petrol mixture & emissions, but only Extensive Studies on Petrol mixture & emissions, but only � few individual compounds examined closely few individual compounds examined closely 8
Petrol – – Toxicology/ Toxicology/Epidemiology Epidemiology Summary Summary Petrol � Petrol Petrol – – overall classification “Probable Carcinogen” overall classification “Probable Carcinogen” � � Based on epidemiological data (worker studies) Based on epidemiological data (worker studies) � � Findings mainly associated with Benzene exposure levels Findings mainly associated with Benzene exposure levels � � Emissions profile (1,3 Emissions profile (1,3- -butadiene) may contribute to risk butadiene) may contribute to risk � � General population unlikely to be at risk General population unlikely to be at risk � � Certain sub Certain sub- -populations with prolonged, significant populations with prolonged, significant � exposures may have increased risks exposures may have increased risks � Neurotoxicity Neurotoxicity issues issues � � Due to aromatics levels Due to aromatics levels � � Toluene/ Toluene/Ethylbenzene Ethylbenzene – – neurotoxicants neurotoxicants at high exposures at high exposures � � Extensive Studies on Mixture & Emissions Extensive Studies on Mixture & Emissions – – over 3,000 over 3,000 � citations in technical literature citations in technical literature 9
Oxygenates - - Fuel Fuel- -Ethanol Ethanol Oxygenates � Denatured Ethanol (fuel Denatured Ethanol (fuel- -ethanol) ethanol) – – health risks uncertainty health risks uncertainty � � Limited toxicological study on ‘neat’ ethanol � Limited toxicological study on ‘neat’ ethanol � Most data for ingestion (rather than inhalation) Most data for ingestion (rather than inhalation) � � Studies on mixture with petrol lacking Studies on mixture with petrol lacking � � Alcoholic Beverages & Consumption Alcoholic Beverages & Consumption � � Broadly classified as Known Human Carcinogen Broadly classified as Known Human Carcinogen � � Broadly classified as reproductive & developmental toxin Broadly classified as reproductive & developmental toxin � � Effects to Effects to immunological immunological system system � � Effects to endocrine/hormonal system Effects to endocrine/hormonal system � � Ethyl Alcohol is single common ingredient to all alcoholic Ethyl Alcohol is single common ingredient to all alcoholic � beverages beverages � Critical uncertainty to health risk is exposure levels Critical uncertainty to health risk is exposure levels � 10
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