Risk Analysis of Contaminated Sites: Human Health and Ecological Risk Assessment F. Quercia, ANPA Workshop ICS/UNIDO - Fundacion Mamonal Environmental Pollution and Applicability of Remediation Technologies in Latin-American Countries Cartegena des India, 4-7 Dec., 2000

Cartagen des India, Land use oriented and risk-based soil management

Cartagen des India, Definitions Risk assessment is an objective, scientific evaluation of the likelihood of unacceptable impacts to human health and the environment Risk is the combination of: –exposure to toxic substances – hazard/toxicity of substances

Cartagen des India, Human Health Risk Assessment

Cartagen des India, Quantitative Risk Assessment Forward versus Backward R.A. Quantitative or Absolute R.A. FW: Assesses baseline risks related to site contamination levels BW: Defines generic guideline values and site-specific clean up goals related to target risk levels

Cartagen des India, Risk Assessment: forward procedure Observed Concentration Estimated Exposure Estimated Risk Baseline Risk Assessment

Cartagen des India, I. Hazard Identification II.Exposure Assessment Desk Study Prelim. CSM Exploratory SI Refined CSM Identification of sources, pathways and receptors Assess source - pathway - receptor linkages and estimate exposure III.Dose/Response Assessment IV: Risk Assessment Assess contaminants human toxicity Combine exposure and toxicological evaluations Note CSM = conceptual site model

Cartagen des India, Source-pathway-receptor one or more routes or means by, or through, which a receptor is being exposed to, or affected by, a contaminant or could be so exposed or affected Pathway a substance which has the potential to cause harm to human health or the environment Source Receptor an individual which is being, or could be, harmed by the source IDENTIFY AND Characterize S - P - R TO BUILD SITE CONCEPTUAL MODEL IDENTIFY AND Characterize S - P - R TO BUILD SITE CONCEPTUAL MODEL

Cartagen des India, Sources Free / immiscible product Water phase with dissolved contamination Air phase with vapours Solid phase with adsorbed contamination

Cartagen des India, Risk estimation and evaluation Uncertainties –Contamination data chemical species concentrations spatial and temporal effects –Characteristics of the sub-surface –Existence/characteristics of pathways –Identity and location of receptors - now and in the future –Fate and transport modelling model selection validation –Exposure assessment –Toxicology

Cartagen des India, Challenges Public acceptability of risk-based approach Uncertainty, sensitivity and conservatism Validation Information overload –hundreds of R&D projects –hundreds of publications –matching research to need Integration of different aspects Availability of practical “tools”

Cartagen des India, Characterize Sources: map of lead concentration in surface soil (<1,5 m deep) m584660m584700m584740m584780m m m m m m not interpolated area mg/kg d.w Hazard Assessment: Spot Contaminants of Concern

Cartagen des India, Exposure Assessment Objectives: assess contaminant concentration and exposure to contact media at receptor contact points Data and tools: data from source, site and receptor characterization. conceptual model parametrization. use of fate and transport (F&T) models

Cartagen des India, Data for Exposure Assessment Chemicals: chemical and physical parameters describing environmental mobility, persistency, volatility, bioaccumulation potentialChemicals: chemical and physical parameters describing environmental mobility, persistency, volatility, bioaccumulation potential Site/pathways: physical/chemical parameters describing local soil, air and water resources conditionsSite/pathways: physical/chemical parameters describing local soil, air and water resources conditions Receptors: data describing land use and receptor exposure characteristics ( exp. routes and parameters)Receptors: data describing land use and receptor exposure characteristics ( exp. routes and parameters) Choose Contaminants of Concern Choose relevant pathways Choose relevant pathways Choose receptors and location Choose receptors and location

Cartagen des India, Exposure Scenario for residential use Transport of leachate to groundwater Drinking water consumption Dust inhalation Vapor inhalation Transport of vapors Dermal contact Soil ingestion Vapors and dust inhalation Groundwater flow

Cartagen des India, Exposure flowchart Soil Groundwater Air Groundwater transport Drinking water ingestion Soil ingestion Dermal contact Vapour and dust indoor and outdoor inhalation Sources Migration routes Exposure pathways Air diffusion and dispersion Industrial Receptors Residential

Cartagen des India, E = Exposure [mg/kg - day] CR = Contact rate [mg/day] EF = Exposure frequency [day/year] ED = Exposure duration [year] BW = Body weight [kg] AT = Averaging time [year] C = Concentration of contaminant in soil [mg/kg] Exposure Assessment

Cartagen des India, UFxMF RfD NOAEL dose (mg/kg/day) response a SF response dose (mg/kg-day) Carcinogenic effects b Toxic effects RfD = Reference Dose (or TDI) for threshold substances [mg/kg - day] SF = Slope Factor (or CPS) for non-threshold substances [1/(mg/kg - day)] RfD = Reference Dose (or TDI) for threshold substances [mg/kg - day] SF = Slope Factor (or CPS) for non-threshold substances [1/(mg/kg - day)] Dose/Response (Toxicity) Assessment Dose/Response (Toxicity) Assessment

Cartagen des India,

Cartagen des India, Risk Assessment RISK = EXPOSURE x TOXICITY Threshold non-cancer substances : HI = Hazard Index E = Chronic Exposure[mg/kg-day] TDI = Toxicity [mg/kg-day] Non-threshold cancer substances: R = incremental lifetime cancer risk E = Chronic Lifetime Exposure [mg/kg-day], SF = Toxicity [1/(mg/kg-day)] Acceptable Risk Criteria: HI = 1 R = 1E-6 1E-4

Cartagen des India, Generic versus site-specific R.A. Generic R.A. implies conservative assumptions of potential exposure scenarios, site, contaminants and receptor properties Site-specific R.A. implies investigations for collection of local environmental data, construction of conceptual model with actual exposure scenarios

Cartagen des India,

Cartagen des India, Backward tiered procedure to assess remediation goals from target risk levels

Cartagen des India, ASTM/RBCA Tiered procedure ASTM/RBCA Tiered procedure

Cartagen des India, ASTM/RBCA Standard ASTM E1739/95 and PS104/98 for risk-based corrective actions on contaminated sites Streamlined tiered procedure for decision making Tier1 develops RBSLs (Risk-Based Screening Levels) look-up tables for each pathway against which site concentrations are compared Tier 2 and Tier3 develop SSTLs (Site specific Target Levels) as site-specific cleanup objectives

Cartagen des India, Main features of RBCA Risk protection level is the same at each Tier As data from investigation increase more focused quality objectives are defined Tier 1 receptor location is on site on top or below source area according to a conservative assumption Tier 2 and 3 receptor position may be at actual location (compliance point)

Cartagen des India, Tier 1: How Soil RBSL are defined For each chemical RBSL are defined for different land uses, i.e.:. residential/agricolture/recreational. commercial/industrial. groundwater extraction for drinking The following pathways may be included:. soil ingestion. dermal contact. outdoor and indoor dust inhalation. indoor and outdoor dust inhalation. groundwater drinking Target receptor for each land use is located right above the contaminated soil source For each chemical RBSL are defined for different land uses, i.e.:. residential/agricolture/recreational. commercial/industrial. groundwater extraction for drinking The following pathways may be included:. soil ingestion. dermal contact. outdoor and indoor dust inhalation. indoor and outdoor dust inhalation. groundwater drinking Target receptor for each land use is located right above the contaminated soil source

Cartagen des India, Groundwater protection : Tier 2 compliance point Point of compliance (edge of site) compliance point (receptor) might be located at some distance from the source

Cartagen des India, Ecological Risk Assessment (ERA)

Cartagen des India,

Cartagen des India, EEC Procedure

Cartagen des India, Available Tools Ecotoxicological tests data: chronic NOEC/LOEC or acute LEC data from experiments (for screening values) PNEC statistical extrapolations from toxicity data (for screening values) Biological assays (site-specific) Biomonitoring (site-specific) Biomarkers (site-specific)

Cartagen des India, Example: The Netherlands Generic risk assessment (potential risks) for the development of Intervention Values, Target Values and Soil use specific Remediation Objectives Site specific risk assessment (actual risks) for deciding about urgency of remediation and priorities

Cartagen des India, Intervention Values Indicate a serious contamination Human health risk protection criteria: îTDI and 1E-6/year excess cancer risk î residential with vegetable garden exposure scenario (multifunctional) î soil ingestion, inhalation, crop consumption Ecological risk protection criteria: î HC50 (protection of 50% species) derived by NOEC (No Observed Effect Concentration ), LOEC (Lowest Observed EC) or LEC (Lethal EC) data î adjustment to soil clay content and organic matter

Cartagen des India, Target Values Indicate a clean soil Ecological risk protection criteria: é negligible risk level:1% of HC5 (protects 95% of species) é negligible risk level soil concentration is summed to background value for metals

Cartagen des India, Ecotoxicological risk-based criteria

Cartagen des India, Soil-use based Remediation Objectives Generic criteria for top soil, non-mobile pollutants and following land uses: éResidential and recreational green areas éNon-recreational public green areas éBuilt-in and paved areas éAgricultural areas and nature reserves Objectives protect from both human health and ecotoxicological risks

Cartagen des India, Site-specific Risk Assessment For remediation urgency: Assess site-specific risk by CSOIL model adapted to local site exposure scenario Assess ecological risks by pragmatic procedure based on: éarea sensitivity éHC50 ésite area for biodiversity preservation ébioassays Note: use of risk assessment to develop site-specific remediation goals is not yet regulated

Cartagen des India, Ecological Risk Assessment (ERA) needs An analytical framework is needed Limited experience with terrestrial ecosystems is available Ecosystem health needs to be defined Fit for use and land use based soil ecological objectives are seeked Site specific ERA approaches are needed

Cartagen des India, Risk estimation and evaluation Uncertainties –Contamination data chemical species concentrations spatial and temporal effects –Characteristics of the sub-surface –Existence/characteristics of pathways –Identity and location of receptors - now and in the future –Fate and transport modelling model selection validation –Exposure assessment –Toxicology

Cartagen des India, Challenges Public acceptability of risk-based approach Uncertainty, sensitivity and conservatism Validation Information overload –hundreds of R&D projects –hundreds of publications –matching research to need Integration of different aspects Availability of practical “tools”