Lecture8 - 1 Risk Assessment and Management Lecture 8:...

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Unformatted text preview: 1 Risk Assessment and Management Lecture 8: Gaussian Plume Models in Environmental Risk Assessment Reading Material of the Week s Stevens and Swackhamer, Environmental Pollution: A Approach to Modelling Human Exposure (From Reading Materials) s Marshall et al. Risk Assessment at a Former Pesticide Production Facility (From Reading Materials) 2 Outline • Accidents – Transport – Human effects • Transport models • Multimedia and multiple pollutants • Air/Soil/Water/Groundwater • Environmental pathways • Matrix of exposure pathways (inhalation, ingestion, dermal contact) with environmental media (air, soil, water) • Conclusions: value of models • Importance of atmospheric pollutants Objectives • Want student to understand environmental pathways. Toxics to human body. • Want student to appriciate how the transport rates through those pathways are modelled: • Structure of models employed • Sources of parameters and their character • Major strengths and weakness of models • Likely precision of parameters and of models • How models fit into quantitative risk assessments 3 Multi-media Pollution Air Emission Direct Inhalation •By humans •By animals eaten by humans Desposition (dry or wet) to land •Consumption by humans •Uptake by plants Plants consumed by humans Plants consumed by animals consumed by humans runoff to surface water as sediment or dissolved •Leaching to groundwater in dissolved phase Multi-media Pollution Water Pathways (ground or surface waters) Direct Insitu exposure •To humans •To fish eaten by humans or by fish eaten by fish eaten by humans Human consumption of water via water supplies Uptake by aquatic plants (from water column or sediment) •Returned to water •Plants consumed by small animals 4 Multi-media Pollution Solid Waste Wind blown particulates and vaporization Sediment carried away by overland flow Leaching to ground waters Conclusions Accuracy of many ecosystem and multimedia models is not known: 1)Provide best estimate of fate of releases from a facility 2)Indicate what media is central for emissions from facility and thus should be watched 3)Provide reasonable upper bound on exposure from a facility so toxicologists can assess risk to humans Media of Concern in Pollutant Transport Surface Water: streams, rivers, lakes, estuaries, bays, oceans Ground Water: unsaturated and saturated zone, deep and shallow Soil: surface, root zone, buried waste. Losses by leaching to ground water, wind, washoff Atmospheric Transport: Big one! You breath it every day Local: released oxidants, irritants, CO, toxics Regional: acid rain, smog. Smog results from sunlight plus NO 2 CO O 2 hydrocarbons Global: Stratopheric ozone depletion, accumulation of greenhouse gases 5...
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Lecture8 - 1 Risk Assessment and Management Lecture 8:...

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