Community Health Community Health Assessment for Assessment for Garfield County: Garfield County: Risk Assessment Risk Assessment Russ Walker, Ph.D. Russ Walker, Ph.D. Professor of Environmental Science Professor of Environmental Science Mesa State College Mesa State College
Outline Outline � Brief overview of risk assessment Brief overview of risk assessment � � Air pollution effects Air pollution effects � � Water pollution effects Water pollution effects � � Soil pollution effects Soil pollution effects � � Recommendations Recommendations �
I. Risk Assessment I. Risk Assessment
Purpose of Risk Assessment Purpose of Risk Assessment � Estimate the threat posed by specific Estimate the threat posed by specific � pollutants under specific conditions pollutants under specific conditions � Typically assessed for an Typically assessed for an “ “average average” ” � person and for an individual experiencing person and for an individual experiencing a “ “reasonable maximum exposure reasonable maximum exposure” ” a
Magnitude of Threat Magnitude of Threat � Increases with Increases with � � Increasing concentration of pollutant in the Increasing concentration of pollutant in the � polluted medium (air, soil, water) polluted medium (air, soil, water) � Increasing intake of the polluted medium (how Increasing intake of the polluted medium (how � much air we breathe or water we drink) much air we breathe or water we drink) � More frequent exposures (days per year) More frequent exposures (days per year) � � Longer exposure duration (years) Longer exposure duration (years) � � Toxicity of the pollutant Toxicity of the pollutant � � Decreases with increasing body weight Decreases with increasing body weight �
Conceptual Model Conceptual Model � Useful tool for understanding actual and Useful tool for understanding actual and � potential exposures potential exposures � Includes Includes � � Pollutant source Pollutant source � � Release mechanism Release mechanism � � Transport mechanism Transport mechanism � � Polluted medium Polluted medium � � Exposure route Exposure route � � Receptor Receptor �
Conceptual Model Conceptual Model � Actual exposure: Pathway from source to Actual exposure: Pathway from source to � receptor is complete receptor is complete � Potential exposure: Pollutant has not yet Potential exposure: Pollutant has not yet � completed the journey from source to completed the journey from source to receptor, but may do so in future receptor, but may do so in future
II. Air Pollution II. Air Pollution Effects Effects
Air Pollutants Associated with Air Pollutants Associated with Natural Gas Operations Natural Gas Operations � Carbon monoxide, nitrogen oxides, Carbon monoxide, nitrogen oxides, � particulate matter particulate matter � Volatile organic compounds Volatile organic compounds � � Benzene Benzene � � Toluene, Toluene, xylenes xylenes � � A variety of others A variety of others � � Ozone Ozone �
Air Pollutants Associated with Air Pollutants Associated with Natural Gas Operations Natural Gas Operations � Focus of this study: benzene, toluene, Focus of this study: benzene, toluene, � xylenes xylenes � Known to occur in natural gas Known to occur in natural gas � � Among volatile organic compounds, had Among volatile organic compounds, had � highest frequency of occurrence in samples highest frequency of occurrence in samples � Benzene is a known human carcinogen Benzene is a known human carcinogen � � Benzene, toluene, Benzene, toluene, xylenes xylenes have significant have significant � non- -carcinogenic effects carcinogenic effects non
Health Effects of Benzene Health Effects of Benzene � Cancer Cancer � � Leukemia Leukemia � � Neurotoxicity Neurotoxicity � � Blood disorders Blood disorders � � Impairment of immune system Impairment of immune system �
Health Effects of Toluene Health Effects of Toluene � Neurological effects such as Neurological effects such as � � Impaired color vision Impaired color vision � � Impaired hearing Impaired hearing � � Headache and dizziness Headache and dizziness � � Possible respiratory irritation Possible respiratory irritation �
Health Effects of Xylenes Xylenes Health Effects of � Mild neurological impairment (such as Mild neurological impairment (such as � reduced motor coordination) reduced motor coordination)
Air Pollutant Transport Air Pollutant Transport Advection carries pollutant downwind carries pollutant downwind � Advection � away from source away from source Turbulence disperses pollutant laterally disperses pollutant laterally � Turbulence � and vertically and vertically
Air Pollutant Transport Air Pollutant Transport
Air Pollutant Transport Air Pollutant Transport � Pollutant is diluted by the wind Pollutant is diluted by the wind – – the the � greater the wind speed, the greater the greater the wind speed, the greater the dilution dilution � Pollutant concentration also determined by Pollutant concentration also determined by � atmospheric stability atmospheric stability � Clear sunny day Clear sunny day – – unstable air with lots of unstable air with lots of � vertical mixing dilutes the pollutant vertical mixing dilutes the pollutant � Night or overcast Night or overcast – – more stable air with less more stable air with less � mixing gives less dilution mixing gives less dilution
Air Pollutant Transport Air Pollutant Transport � Complications to basic picture Complications to basic picture � � Variation in wind direction over time Variation in wind direction over time � � Variability in terrain Variability in terrain � � Presence of trees, buildings Presence of trees, buildings � � Stability of atmosphere Stability of atmosphere �
Obtaining Air Pollutant Obtaining Air Pollutant Concentrations Concentrations � Needed for risk assessment Needed for risk assessment � � Best approach Best approach � � Collect samples representative of the range of Collect samples representative of the range of � concentrations and conditions that occur concentrations and conditions that occur � Analyze samples to obtain pollutant Analyze samples to obtain pollutant � concentrations (micrograms per cubic meter) concentrations (micrograms per cubic meter)
Air Pollutant Concentrations Air Pollutant Concentrations � Volatile organics in the Garfield County Volatile organics in the Garfield County � Ambient Air Quality Monitoring Study, Ambient Air Quality Monitoring Study, June 2005 – – May 2007 May 2007 June 2005 � Samples collected over periods of 24 hours Samples collected over periods of 24 hours � from 7 sites – – 232 total samples 232 total samples from 7 sites � “ “Grab Grab” ” samples collected over periods of 15 samples collected over periods of 15 � seconds at 7 additional sites, motivated by seconds at 7 additional sites, motivated by odor complaints – – 27 total samples 27 total samples odor complaints
Ambient Air Study – – Results Results Ambient Air Study � Benzene Benzene � � 24 24- -hour samples hour samples � � Average concentration: 2.2 Average concentration: 2.2 μ μ g/m g/m 3 3 � � Maximum concentration: 49 Maximum concentration: 49 μ μ g/m g/m 3 3 � � Grab samples Grab samples � � Average concentration: 28 Average concentration: 28 μ μ g/m g/m 3 3 � � Maximum concentration: 180 Maximum concentration: 180 μ μ g/m g/m 3 3 � ( μ μ g/m g/m 3 3 = micrograms per cubic meter) ( = micrograms per cubic meter)
Ambient Air Study – – Results Results Ambient Air Study � Toluene Toluene � � 24 24- -hour samples hour samples � � Average concentration: 7.4 Average concentration: 7.4 μ μ g/m g/m 3 3 � � Maximum concentration: 130 Maximum concentration: 130 μ μ g/m g/m 3 3 � � Grab samples Grab samples � � Average concentration: 91 Average concentration: 91 μ μ g/m g/m 3 3 � � Maximum concentration: 540 Maximum concentration: 540 μ μ g/m g/m 3 3 �
Ambient Air Study – – Results Results Ambient Air Study -Xylenes Xylenes m,p - � m,p � � 24 24- -hour samples hour samples � � Average concentration: 3.9 Average concentration: 3.9 μ μ g/m g/m 3 3 � � Maximum concentration: 24 Maximum concentration: 24 μ μ g/m g/m 3 3 � � Grab samples Grab samples � � Average concentration: 107 Average concentration: 107 μ μ g/m g/m 3 3 � � Maximum concentration: 1500 Maximum concentration: 1500 μ μ g/m g/m 3 3 �
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