COMPLEMENTARY HUMAN HEALTH RISK ASSESSMENT

Transcription

1 COMPLEMENTARY HUMAN HEALTH RISK ASSESSMENT La Oroya Metallurgical Complex Prepared for Doe Run Peru Victor Andres Belaunde 147 Torre Real 3, Piso 9, San Isidro Lima, Peru Prepared by 7900 SE 28 th Street Suite 410 Mercer Island, WA November 21, 2008

2 CONTENTS LIST OF FIGURES...vi LIST OF TABLES...viii ACRONYMS AND ABBREVIATIONS...xi GLOSSARY OF TERMS...xiv EXECUTIVE SUMMARY... xvii 1 INTRODUCTION RISK ASSESSMENT APPROACH AND SCOPE SUMMARY OF THE 2005 RISK ASSESSMENT REPORT ORGANIZATION SITE CHARACTERIZATION DESCRIPTION OF THE COMPLEX AND ITS OPERATIONS Updates to the Complex Chemicals Released from the Complex COMMUNITY INTERVENTIONS DESCRIPTION OF SURROUNDING POPULATION IDENTIFICATION OF EXPOSURE PATHWAYS DATA EVALUATION SUMMARY OF EXISTING DATA Air Monitoring Data Soil Data Dust Data Drinking Water Data Blood Lead Data Food and Diet Data Worker Morbidity and Mortality Data AIR MODELING ACTIVITIES CHEMICALS TO BE EVALUATED Chemicals in Air Chemicals in Surface Soil Chemicals in Outdoor Dust Chemicals in Indoor Dust Chemicals in Water Chemicals in Diet Integral Consulting Inc. ii

3 4 EXPOSURE ASSESSMENT ASSESSING EXPOSURES TO SULFUR DIOXIDE AND PARTICULATE MATTER Sulfur Dioxide Particulate Matter ASSESSING EXPOSURES TO LEAD Exposure Models for Children Adult Lead Exposure Model ASSESSING EXPOSURES TO METALS OTHER THAN LEAD Exposure Assumptions for All Pathways Soil and Dust Ingestion Intakes Inhalation Intakes TOXICOLOGICAL ASSESSMENT OVERVIEW OF TOXICOLOGICAL EVALUATION PROCESS Evaluation of Carcinogenic Effects Evaluation of Noncarcinogenic Effects SULFUR DIOXIDE AND PARTICULATES Sulfur Dioxide and Sulfuric Acid Health Effects Sulfur Dioxide Health Based Criteria Particulate Matter Health Effects and Health based Criteria LEAD Lead Toxicokinetics Lead Health Effects Lead Carcinogenicity ARSENIC Arsenic Toxicokinetics Arsenic Health Effects CADMIUM Cadmium Toxicokinetics Cadmium Health Effects Cadmium Carcinogenicity ANTIMONY Antimony Toxicokinetics Antimony Health Effects Antimony Carcinogenicity COPPER Copper Toxicokinetics Integral Consulting Inc. iii

4 5.7.2 Copper Health Effects Copper Carcinogenicity THALLIUM Thallium Toxicokinetics Thallium Health Effects Thallium Carcinogenicity HEALTH EFFECTS OF MIXTURES RISK CHARACTERIZATION SULFUR DIOXIDE AND PARTICULATE MATTER HEALTH RISKS Sulfur Dioxide Risk Characterization Particulate Matter Risk Characterization LEAD HEALTH RISKS Influence of Altitude, Anemia, and Lead Toxicity on Blood Lead Levels Lead Health Risks in Children Lead Health Risks for Adults RISKS FOR METALS OTHER THAN LEAD Characterization of Cancer Risks Characterization of Noncancer Risks EVALUATION OF RISKS FROM MULTIPLE CHEMICAL EXPOSURES Effects on the Lung Neurological Effects Anemia Effects on Bone UNCERTAINTY EVALUATION Risk Assessment Scope Confidence in the Risk Assessment Children s Blood Lead Model Sensitivity Analysis CONCLUSIONS AND RECOMMENDATIONS FACILITY OPERATIONS EXPOSURE ASSESSMENT AND ENVIRONMENTAL MONITORING Air Monitoring Air Modeling Monitoring of Metals in Dustfall and Outdoor Dust Integral Consulting Inc. iv

5 7.3 COMMUNITY INTERVENTIONS DIETARY STUDIES AND INTERVENTIONS REFERENCES Appendix A. Appendix B. Appendix C. Memorandum: Discussion of La Oroya Blood Lead Data Quality Issues Memorandum: Evaluation of La Oroya Blood Lead Data Reliability for Use in Risk Assessment Memorandum: Morbidity and Mortality of Workers at Doe Run Peru Metallurgical Complex in La Oroya, Peru Integral Consulting Inc. v

6 Figure 2 1 Figure 2 2 Figure 3 1 LIST OF FIGURES Exposure Pathways for Emissions from the Complex (Fuentes de Exposición a Emisiones) Exposure Pathways for Lead (Fuentes de Exposición a Plomo) Air Monitoring Stations and Community Locations (Estaciónes de Monitoreo de Aire y ubicación dentro de la communidad) Figure 3 2 Suspension in Plant Operations in 2007 Figure 3 3 Mean Blood Lead Levels in Children Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 3 8 Figure 3 9 Figure 3 10 Figure 3 11 Iron Intake as a Percentage of the Recommended Daily Intake Mean Daily Iron Intake for Women and Children Mean Daily Zinc Intake for Women and Children Zinc Intake as a Percentage of the Recommended Daily Intake Calcium Intake as a Percentage of the Recommended Daily Intake Mean Daily Calcium Intake for Women and Children Protein Intake as a Percentage of the Recommended Daily Intake Vitamin C Intake as a Percentage of the Recommended Daily Intake Figure 4 1 Average Hourly Sulfur Dioxide Concentration, Sindicato, 2007 Figure 4 2 Average Hourly Sulfur Dioxide Concentration, Hotel Inca, 2007 Figure 4 3 Average Hourly Sulfur Dioxide Concentration, Marcavalle, 2007 Figure 4 4 Average Hourly Sulfur Dioxide Concentration, Huari, 2007 Figure 5 1 Figure 5 2 Lead Concentration in Blood Historical Blood Lead Levels of Concern Selected by the CDC Figure 6 1 Exceedance of Peruvian Air Quality Standards for SO2 in 2007 Figure 6 2 Number of hours per day that sulfur dioxide levels exceed the AEGL 1 (524 μg/m 3 ) at Sindicato Figure 6 3 Number of hours per day that sulfur dioxide levels exceed the AEGL 1 (524 μg/m 3 ) at Hotel Inca Figure 6 4 Number of hours per day that sulfur dioxide levels exceed the AEGL 1 (524 μg/m 3 ) at Marcavalle Integral Consulting Inc. vi

7 Figure 6 5 Number of hours per day that sulfur dioxide levels exceed the AEGL 1 (524 μg/m 3 ) at Huari Figure 6 6 Figure 6 7 Figure 6 8 Figure 6 9 Figure 6 10 Figure 6 11 Figure 6 12 Figure 6 13 Total number of hours in 2007 sulfur dioxide concentrations exceed the AEGL 1 (524 μg/m) at Sindicato Total number of hours in 2007 sulfur dioxide concentrations exceed the AEGL 1 (524 μg/m) at Hotel Inca Total number of hours in 2007 sulfur dioxide concentrations exceed the AEGL 1 (524 μg/m) at Marcavalle Total number of hours in 2007 sulfur dioxide concentrations exceed the AEGL 1 (524 μg/m) at Huari Number of hours per day in 2007 when sulfur dioxide concentrations exceed the AEGL 2 (1,965 μg/m 3 ) at Sindicato Number of hours per day in 2007 when sulfur dioxide concentrations exceed the AEGL 2 (1,965 μg/m 3 ) at Hotel Inca Number of hours per day in 2007 when sulfur dioxide concentrations exceed the AEGL 2 (1,965 μg/m 3 ) at Marcavalle Number of hours per day in 2007 when sulfur dioxide concentrations exceed the AEGL 2 (1,965 μg/m 3 ) at Huari Integral Consulting Inc. vii

8 Table 3 1 Table 3 2 Table 3 3 Table 3 4 LIST OF TABLES Percent of Hours during Monitoring Period with Usable Sulfur Dioxide Data (2007) Percent of Hours during Monitoring Period with Usable Particulate Data (2007) Percent of Hours during Monitoring Period with Usable Metals in PM10 data (2007) 2007 Soil Sampling (3 10 cm) Mean Values from Three Samples (Mar., Oct., Dec. 2007) Table 3 5 Summary of Surface Soil (0 2 cm) Samples Collected in 2008 Table 3 6 Summary of Subsurface Soil (2 10 cm) Samples Collected in 2008 Table 3 7 Predicted Concentrations of Sulfur Dioxide after 2009 (mg/m 3 ) Table 3 8 Summary of Outdoor Dust Samples Collected in 2008 Table 3 9 Metals in Drinking Water 2007 Table 3 10 Childrenʹs Blood Lead Levels ( ) Table 3 11 Table 3 12 November 2007 Blood Lead Levels in La Oroya Children Concentration of Metals in Food Samples (mg/kg) Table 3 13 Predicted Concentrations of Lead in PM10 after 2009 (mg/m 3 ) Table 3 14 Table 3 15 Table 3 16 Table 3 17 Table 3 18 Table 3 19 Table 3 20 Table 3 21 Table 4 1 Summary Statistics and Selection of COPCs for Air Summary Statistics and Selection of COPCs for Outdoor Dust Summary Statistics and Selection of COPCs for Indoor Dust Summary Statistics and Selection of COPCs for Surface Soil Summary Statistics and Selection of COPCs for Drinking Water Chemical Screening Criteria Comparison of Available Soil Data for Use in the Update Comparison of 2007 and 2008 Convenio Household Dust Data Annual Average and Second Highest Daily Average Concentrations of Sulfur Dioxide (mg/m 3 ) Table 4 2 Annual Average and Second Highest Daily Average Concentrations (mg/m 3 ) of Coarse Particulate Matter (PM10) Integral Consulting Inc. viii

9 Table 4 3 PM2.5 Concentrations by Station 2007 Table 4 4 Table 4 5 Table 4 6 ISE Input Parameters Used for All Simulations ISE Input Parameters That Vary With Time and/or Community La Oroya Antigua ISE Input Parameters That Vary with Time and Community La Oroya Nueva Table 4 7 ISE Input Parameters That Vary with Time and Community Marcavalle/Chucchis Table 4 8 Table 4 9 Table 4 10 Table 4 11 Table 4 12 Table 4 13 Table 4 14 Table 4 15 Table 4 16 Table 4 17 Table 4 18 Table 5 1 Table 5 2 Table 5 3 Table 5 4 ISE Input Parameters That Vary with Time and Community Huari ISE Input Parameters That Vary with Time and Community Paccha 2007 Blood Lead Sample of Pregnant Women in La Oroya Statistical Comparison of 2004 and 2007 Children Blood Lead Data Summary of Input Values for Future ISE Modeling for La Oroya Antigua Summary of Input Values for Future ISE Modeling for La Oroya Nueva Summary of Input Values for Future ISE Modeling for Marcavalle/Chucchis Input Parameters for the ALM Model Calculation of Site Specific GSD for La Oroya Using Blood Lead Sampling Data for Year 2007 Comparison of 2007 Adult Blood Lead Data and ALM Model Results Exposure Parameters for Adult and Child Residents Ingestion Toxicity Criteria Inhalation Toxicity Criteria Summary of Sulfur Dioxide Standards Summary of Ambient Air Quality Standards for Particulate Matter Table 6 1 Hourly Exceedance of Sulfur Dioxide AEGL 1 (524mg/m 3 ) Table 6 2 Hourly Exceedance of Sulfur Dioxide AEGL 2 (1,965mg/m 3 ) Table 6 3 Maximum Hourly Sulfur Dioxide Values (mg/m 3 ) by Month 2007 Table 6 4 Estimated Annual Stack and Fugitive Sulfur Dioxide Emissions Table 6 5 Predicted Sulfur Dioxide Concentration in Ambient Air (μg/m 3 ) Table 6 6 ISE Model Results for 2007 and 2009 Table 6 7 Comparison of 2007 Sampling Data and Modeled Blood Lead Concentrations Integral Consulting Inc. ix

10 Table 6 8 Table 6 9 Table 6 10 Table 6 11 Table 6 12 Table 6 13 Table 6 14 Table 6 15 Table 6 16 Table 6 17 Table 6 18 Table 6 19 Relative Contributions from Different Media to 2007 Modeled Child Blood Lead Concentrations Relative Contributions from Different Media to 2009 Modeled Child Blood Lead Concentrations Predicted Adult and Fetal Blood Lead Concentrations Summary of Current Cancer Risks Ingestion Exposures Summary of Current Cancer Risks Inhalation Exposures Summary of Cancer Risks for Post 2009 Ingestion Exposures Summary of Cancer Risks for Post 2009 Inhalation Exposures Summary of Current Noncancer Risks Ingestion Exposures Summary of Current Noncancer Risks Inhalation Exposures Summary of Noncancer Risks for Post 2009 Ingestion Exposures Summary of Noncancer Risks for Post 2009 Inhalation Exposures Key Uncertainties for the Human Health Risk Assessment Integral Consulting Inc. x

11 ACRONYMS AND ABBREVIATIONS AEGL ALAD ALM AQG ASTM ATSDR Blufstein CCME CDC CENSOPAS CFR Complex CONAM Convenio COPC CSF CTE DHHS DIGESA DRP EHP EKG EPC G6PD GSD GSH acute exposure guideline level δ aminolevulinic acid dehydratase adult lead exposure model air quality guideline American Society for Testing and Materials United States Agency for Toxic Substances and Disease Registry Blufstein Clinical Laboratory S.A. Canadian Council of Ministers of the Environment United States Centers for Disease Control and Prevention Centro Nacional de Salud Ocupacional y Protección del Ambiente para la Salud Code of Federal Regulations Doe Run Peru La Oroya Metallurgical Complex Consejo Nacional del Ambiente Convenio de Cooperacion MINSA, Gobierno Regional Junin, Doe Run Peru chemical of potential concern cancer slope factor central tendency exposure United States Department of Health & Human Services Ministry of Health s Environmental Health Directorate (Direcciòn General de Salud Ambiental) Doe Run Peru Environmental Health Project electrocardiogram exposure point concentration glucose 6 phosphate dehydrogenase geometric standard deviation glutathione Integral Consulting Inc. xi

12 GWI HQ IARC ICC IEUBK IIN INEI Integral IOM IPCS IRIS ISA ISE LOAEL LOEL MEM MINSA MM5 MMA MRL NAAQS NAC NAS NCEH NIOSH NOAEL NRC NTP PAHO PAMA Ground Water International hazard quotient International Agency for Research on Cancer Indian childhood cirrhosis Integrated exposure uptake biokinetic model Instituto de Investigacion Nutricional National Institute of Statistics and Information Integral Consulting Inc. Institute of Medicine International Programme on Chemical Safety Integrated Risk Information System integrated science assessment integrated stochastic exposure lowest observed adverse effects level lowest observed effect level Peruvian Ministry of Energy and Mines Peruvian Ministry of Health meso scale model McVehil Monnett Associates, Inc. minimum risk level National Ambient Air Quality Standards National Advisory Committee for Acute Exposure Guideline Levels United States National Academy of Sciences National Center for Environmental Health National Institute of Occupational Safety and Health no observed adverse effects level National Research Council National Toxicology Program Pan American Health Organization Project of the Environmental and Management Program Integral Consulting Inc. xii

13 PM10 PM2.5 QA/QC RAF RDA RfC RfD RME SO2 SUNASS TOR UCDEH UCLM UL USEPA WHO WOE ZPP particulate matter with diameter smaller than 10 microns particulate matter with diameter smaller than 2.5 microns quality assurance and quality control relative absorption factor recommended dietary allowance reference concentration reference dose reasonable maximum exposure sulfur dioxide Superintendencia Nacional de Servicio de Saneamiento terms of reference University of Cincinnati Department of Environmental Health upper confidence limit of the mean upper intake level United States Environmental Protection Agency World Health Organization weight of evidence zinc protoporphyrin Integral Consulting Inc. xiii

14 GLOSSARY OF TERMS Accuracy: The degree to which a measurement reflects the true quantitative value of a variable. Acute: Having a sudden onset or lasting a short time. An acute stimulus is severe enough to induce a response rapidly. The word acute can be used to define either the exposure or the response to an exposure (effect). Air Quality Criteria: Maximum legally allowable concentrations for air pollutants that are intended to protect public health, including sensitive populations such as asthmatics, children and the elderly. Carcinogen: An agent capable of inducing cancer. Chronic: Involving a stimulus that is lingering or continues for a long time; often signifies periods from several weeks to years, depending on the reproductive life cycle of the species. Chronic can be used to define either the exposure or the response to an exposure (effect). Chronic exposures typically induce a biological response of relatively slow progress and long duration. Confidence Limit: Either of the two numbers that specify the endpoints of the confidence interval. Deposition: The processes by which chemical constituents settle from the atmosphere to the earthʹs surface, which include precipitation (wet deposition, such as rain or cloud fog) and particle and gas deposition (dry deposition). Exposure: The contact of people with chemicals. Exposure Medium: The contaminated environmental medium to which an individual is exposed, such as soil, water, sediment and air. Exposure Pathway: The path a chemical or physical agent takes from a source to an exposed organism. An exposure pathway describes a unique mechanism by which an individual or population is exposed to chemicals or physical agents at or originating from a site. Each exposure pathway includes a source or release from a source, an exposure point, and an exposure route. If the exposure point differs from the source, a transport/exposure medium (e.g. air) or media (in cases of intermedia transfer) also is included. Exposure Pathway Model: A model in which potential pathways of exposure are identified for the selected receptor species. Integral Consulting Inc. xiv

15 Exposure Point: The potential contact between a person and a contaminant within an exposure medium. Exposure Point Concentration: The value that represents a conservative estimate of the chemical concentration available from a particular medium or route of exposure. Exposure Route: The mechanism for which a contaminant comes in contact with a person (e.g., by ingestion, inhalation, dermal contact). Exposure Scenario: A set of assumptions concerning how an exposure takes place, including assumptions about the exposure setting, stressor characteristics, and activities of an organism that can lead to exposure. Fugitive Emissions: Air emissions that do not pass through a stack, chimney, vent, or other functionally equivalent opening. Gamma Distribution: In probability theory and statistics, the gamma distribution is a continuous probability distribution. In a probability distribution, every interval of the real number is assigned a probability so that the probability axioms are satisfied. Hazard Index: The ratio of an exposure level to a substance to a toxicity value selected for the risk assessment for that substance. Lognormal Distribution: In probability theory and statistics, the lognormal distribution is the probability distribution of any random variable whose logarithm is normally distributed. Mean: The average value of a set of numbers. Media: Specific environmental components air, water, soil which are the subject of regulatory concern and activities. Median: The middle value in an ordered set of numbers. Noncancer Risk: Characterized as the increased likelihood that an individual will suffer adverse health effects as a result of exposure to a chemical. Non carcinogen: An agent not capable of inducing cancer. Particulate Matter: Material suspended in the air in the form of minute solid particles or liquid droplets, especially when considered as an atmospheric pollutant Precision: A measure of the closeness of agreement among individual measurements. Integral Consulting Inc. xv

16 Risk Assessment: A qualitative or quantitative evaluation of the risk posed to human health and/or the environment by the actual or potential presence or release of hazardous substances, pollutants, or contaminants. Risk Characterization: The integration of information on hazard, exposure, and dose response to provide an estimate of the likelihood that any of the identified adverse effects will occur in exposed individuals. Risk Evaluation: The evaluation of scientific information on the hazardous properties of environmental agents (hazard characterization), the dose response relationship (dose response assessment), and the extent of human exposure to those agents (exposure assessment). The product of the risk assessment is a statement regarding the probability that populations or individuals so exposed will be harmed and to what degree (risk characterization). Screening Criteria: A risk based concentration of a chemical in an environmental medium (e.g., soil, air, etc) that is considered protective of public health and can be used to compare to chemical data to determine if a chemical is present in the environmental medium at concentrations that may present a hazard to public health. Stack Emissions: The particulate matter and vapors captured and released to the atmosphere through a stack, chimney, vent, flue, or other functionally equivalent opening. Toxicity Values: A numerical expression of a substanceʹs exposure response relationship that is used in risk assessments Integral Consulting Inc. xvi

17 EXECUTIVE SUMMARY This document presents a complementary human health risk assessment for the Doe Run Peru Metallurgical Complex (Complex) in La Oroya, Peru. It updates a risk assessment prepared by Integral Consulting Inc. (Integral) in The focus of the earlier risk assessment had been to characterize risks to nearby residents from chemicals released to the air during current and future operations of the Complex. In response to a request from the Ministry of Energy and Mines to update the 2005 risk assessment, Doe Run Peru contracted Integral to conduct the update. The same methods were used in both risk assessments; this update incorporates new data reflecting current conditions. Future scenarios were also predicted on the basis of planned changes at the Complex by Doe Run Peru. STUDY AREA The Complex is located approximately 175 kilometers northeast of Lima, Peru in the Andes Mountain Range, at an altitude of 3,745 meters. It is situated in the Mantaro River Valley at the confluence of the Mantaro and Yauli Rivers. This risk assessment presents estimates of health risks for the communities of La Oroya Antigua, La Oroya Nueva, Marcavalle, Chucchis, Santa Rosa de Sacco, Huaynacancha, Paccha, and Huari. Adjacent to and north of the Complex, across the Mantaro River, is the town of La Oroya Antigua. The communities of La Oroya Nueva, Marcavalle, Chucchis, Santa Rosa de Sacco, and Huaynacancha are located upstream, along the Yauli River, at increasing distances west southwest of the Complex. Paccha is upstream along the Mantaro River, while Huari is downstream of the Complex. The Complex was built by American Cerro de Pasco Copper Corporation and began smelting copper in Lead production began in 1928 and zinc production began in Recovery of precious metals began in The government owned company, Centromin, operated the Complex from 1974 until 1997, when it was purchased by the Doe Run Company. The Complex is an operating smelter that processes approximately 600,000 metric tons of concentrate annually. Eleven metals, including lead, zinc, copper, silver, and gold, and eight by products are produced from the concentrate. A main stack rising meters above ground level emits gases and particulate matter produced during smelter operation. There is also a much smaller stack called the sinter plant stack. In addition, gases and particulate emissions escape from various buildings, ductwork, and machinery at the Complex. These fugitive emissions and those from the main stack contain heavy metal dusts and sulfur dioxide gas that migrate to the surrounding communities at levels capable of causing adverse health effects. Integral Consulting Inc. xvii

18 RISK ASSESSMENT DEFINITION, 2005 RESULTS AND 2008 OBJECTIVES A human health risk assessment is a quantitative evaluation of the risk posed to human health by the actual or potential presence or release of chemicals in the environment. It predicts the likelihood of health effects in a population, but does not directly measure their occurrence. In this way, a risk assessment is very different from an epidemiology study that reports the incidence of specific health effects or a biomonitoring study that reports the concentrations of chemicals in people s bodies. The value of a risk assessment is that it is a tool to better understand the factors contributing to chemical exposures and to predict conditions in the future. The risk assessment conducted in 2005 concluded that the residents of La Oroya had elevated risks of adverse health effects from chemicals released by the Complex. Both sulfur dioxide and air particulates were found to exceed air quality criteria. As expected from available blood lead data for La Oroya residents, risks of adverse health effects due to lead exposures were markedly elevated. Cancer risks from inhalation of arsenic in air and from incidental ingestion of arsenic in dust and soil were found to be unacceptably high. The risks of adverse health effects other than cancer were also found to be elevated for inhalation of cadmium and arsenic in air and for ingestion of arsenic and antimony in dust and soil. The 2005 risk assessment evaluated the potential that future risks could be lowered by operational changes to reduce stack and fugitive emissions. Factors that contribute to the elevated health risks were examined, and actions in the form of community and dietary interventions to reduce exposures and mitigate health impacts were recommended. This update of the risk assessment for La Oroya is needed to evaluate the progress of efforts to reduce emissions from the Complex and to predict future health risks as emissions are further reduced. The complementary risk assessment includes the following key components: Updates to the site characterization and exposure pathway model based on the findings from the 2005 risk assessment and recent updates to the Complex A summary and evaluation of existing data and details of the process used to select chemicals of concern An exposure assessment based on new data and the updated air model An update of the toxicity assessment for chemicals included in the risk assessment Characterization of current and future risks and a discussion of uncertainty associated with the risk estimates Recommendations for future actions and assessments in La Oroya. Integral Consulting Inc. xviii

19 2008 RISK ASSESSMENT METHODS This complementary risk assessment was conducted with the same methods used in Available data were compiled and the data adequacy to support the risk assessment was evaluated. Air monitoring data collected during 2007 at six air monitoring stations operated by Doe Run Peru were used to evaluate sulfur dioxide, particulate, and metal concentrations in air. Data from samples collected in June 2008 by Doe Run Peru were used to assess metals concentrations in surface soil and outdoor dust. Data from samples collected by the Convenio during 2007 and 2008 were used to assess metals in indoor dust. Drinking water data on metals also came from samples collected by the Convenio. Blood lead data for children and pregnant women used in the risk assessment were collected by the Blufstein Clinical Laboratory in November Additionally, a Convenio sponsored study to evaluate the micronutrient and metals content in food, completed in April 2008, provided information on lead content in the diet. Thus, available data include chemical concentrations in air, soil, dust, drinking water, and food, as well as blood lead concentrations in children and pregnant women. A risk based screening process was used to determine which chemicals associated with the Complex should be included in the risk assessment, and exposure pathways were identified. Consistent with the 2005 risk assessment, different approaches were used to evaluate different chemicals. Inhalation of sulfur dioxide and air particulates was assessed by comparing annual average and 24 hour air concentrations during 2007 with Peruvian and United States air quality criteria. These comparisons were carried out using data from monitoring stations located in the following communities: La Oroya Antigua, La Oroya Nueva, Marcavalle (and Chucchis), Huaynacancha, Paccha, and Huari. To assess health risks from lead exposures, an exposure model developed for the United States Environmental Protection Agency (USEPA) was modified to reflect conditions in La Oroya and then used to produce a distribution of blood lead concentrations. The validity of this model was assessed by comparing the model results with blood lead levels measured in the children of La Oroya during November Initially, the exposure parameters developed for the 2005 risk assessment were used along with new data for lead concentrations in air, soil, outdoor dust, indoor dust, drinking water, and food. A small number of exposure parameters were then modified to produce a better fit with the November 2007 blood lead data. A similar process was used to update the lead exposure model for adults. To characterize risks of other metals, quantitative estimates of exposure and toxicity were combined to yield numerical estimates of potential health risk. For carcinogens, USEPA s acceptable range of risks is an incremental lifetime risk of 1 in 10,000 to 1 in 1 million. The term incremental reflects the fact that the calculated risk associated with site related exposure is in addition to the background risk of cancer experienced by all individuals in the course of daily life. Cancer risk estimates are expressed as unitless values reflecting the additional probability that an individual will develop cancer over a lifetime of exposure. Arsenic and cadmium are carcinogenic when inhaled, and Integral Consulting Inc. xix

20 arsenic is carcinogenic if ingested at very high doses; accordingly, cancer risks were assessed for inhaled arsenic and cadmium, and for ingested arsenic. Noncancer health risks of other metals, including arsenic, cadmium, antimony, and copper, were characterized as the increased likelihood that an individual will suffer adverse health effects as a result of exposure. For health effects other than cancer, estimated exposures were compared with toxicity values that represent doses of a chemical that will not cause adverse health effects in any members of a population (i.e., reference dose). This comparison yields a hazard index. If the hazard index does not exceed a value of 1.0, no adverse health effects are expected. Thus, consistent with USEPA guidance, the target risk for health effects other than cancer is a hazard index of 1.0. Future health risks are anticipated to decline after completion of additional projects to reduce emissions from the Complex. Specifically, acid plants will be added to the zinc circuit (in September 2008) and copper circuit (in October 2009), significantly reducing stack emissions of sulfur dioxide and metals. The air dispersion model used for the 2005 risk assessment was updated by McVehil Monnett Associates, Inc. to predict the reductions in air concentrations of sulfur dioxide and particulates and in deposition of metals in dust after The results of this model were used to predict future risks. The complementary risk assessment also includes a review of and updates to the recommendations made in the 2005 risk assessment RISK ASSESSMENT RESULTS This complementary risk assessment confirms the continued existence of the health risks found in The magnitude of exposures to lead and other metals during 2007 has been substantially reduced compared with 2005; however, these risks remain elevated above acceptable levels. Risks related to sulfur dioxide exposure have slightly increased in many areas around the Complex. SULFUR DIOXIDE AND PARTICULATES The annual average sulfur dioxide concentrations at all six of the monitors exceeded the annual average ambient air quality standard of 80 μg/m 3 established by the government of Peru for sulfur dioxide, with concentrations ranging from 706 μg/m 3 for La Oroya Antigua to 110 μg/m 3 for Paccha. The Peruvian 24 hour standard (365 μg/m 3 ) was exceeded most frequently and by the greatest degree at the monitor in La Oroya Antigua. The standard was exceeded on 267 days, and the second highest 24 hour sulfur dioxide concentration was nearly 8 times the Peruvian standard. There were also frequent exceedances of the standard in La Oroya Nueva, Marcavalle/Chucchis, and Huari, with rare exceedances in Paccha and Huaynacancha. Integral Consulting Inc. xx

21 An evaluation of short term hourly sulfur dioxide concentrations (in comparison with acute exposure guideline values) predicted that some members of the population may experience temporary respiratory effects such as wheezing, tightness of the chest, and coughing, but concentrations were well below lethal or life threatening levels. Individuals such as asthmatics and children are more likely to experience adverse health effects from elevated sulfur dioxide exposures. Adverse respiratory effects from sulfur dioxide exposure typically end within hours of the time when the elevated exposure ceases. As a result of several technical modifications at the Complex, sulfur dioxide impacts are predicted to decrease dramatically after Annual average concentrations are predicted to decline by 78 to 82 percent and maximum 24 hour average concentrations are anticipated to be 60 to 66 percent lower. In addition to the planned changes to the Complex, an alternative scenario was constructed in which the main stack is located on Cerro Somi, producing an additional 100 meters of elevation to the stack. Based on this model, annual average concentrations are predicted to decrease by 75 to 93 percent and maximum 24 hour average concentration are estimated to be 78 to 81 percent lower. The Peruvian 24 hour sulfur dioxide standard will drop from 365 μg/m 3 at present (2008) to 80 μg/m 3 in 2009 and then to 20 μg/m 3 in It is assumed that these changes will render the annual standard irrelevant. Despite the marked reductions in sulfur dioxide emissions in both scenarios described above, air concentrations will remain well above the new Peruvian standard. However, the magnitude of the emissions reductions means that there will be many fewer hours when sulfur dioxide concentrations could induce respiratory effects. For particulates, the highest annual average concentrations of PM10 (particles with diameter less than 10 microns) in 2007 were detected in La Oroya Antigua and the lowest concentrations were detected in Paccha. The annual average concentration in La Oroya Antigua was 64 μg/m 3, 28 percent higher than the Peruvian standard of 50 μg/m 3. The Peruvian standard was also exceeded at Marcavalle/Chucchis (52 μg/m 3 ) and Huaynacancha (64 μg/m 3 ), but not at La Oroya Nueva (equivalent to the standard). Values at both Huari (46 μg/m 3 ) and Casaracra (26 μg/m 3 ) fell below the standard. The 24 hour average PM10 standard of 150 μg/m 3, not to be exceeded more than three times per year, was exceeded only once in La Oroya Antigua, and not at all at the other monitors. Because this standard allows three exceedances per year, all areas were in compliance. In the future, particulates are more likely to be evaluated by means of comparison with standards for fine particulate matter or PM2.5 (diameter less than 2.5 microns). In 2007, maximum 24 hour values of PM2.5 all fell below the current Peruvian standard of 65 μg/m 3. However, it has been proposed that the PM2.5 standard be reduced to 50 μg /m 3 starting in 2010 and to 25 μg/m 3 in Particulate concentrations after 2009 were not predicted by the air dispersion model because of the numerous other sources of air particulates in La Oroya that have not been characterized. After 2009, contributions of the Complex to air particulates will be markedly Integral Consulting Inc. xxi

22 reduced, but the contributions from other sources may limit the observed reductions in PM10 and PM2.5.. LEAD Risks of adverse health effects from lead exposures in 2007 were reduced compared with those in 2005, but remain unacceptably elevated, particularly in children in La Oroya Antigua. Health risks associated with lead exposure are assessed by comparing the observed or predicted blood lead concentrations in a population with levels known to cause specific adverse health effects. The number and severity of health effects increases with dose. The United States Centers for Disease Control and Prevention (CDC) has identified 10 μg/dl as a level of concern and as the concentration above which additional monitoring is recommended. In 2007, the mean blood lead level for all children under age 6 in the area was 18 μg/dl, with a maximum value of 55 μg/dl. In La Oroya Antigua, the mean value was 21 μg/dl; this compares with a 2004 mean of 32 μg/dl. For 2007 the model predicts that 100 percent of children in La Oroya Antigua had blood lead levels greater than 10 μg/dl; however, risk that blood lead levels exceeded 10 μg/dl for other communities ranges from 36 percent in Paccha to 93 percent in La Oroya Nueva. Predictions for after 2009, when planned operational changes will have been implemented, indicate further declines in children s blood lead levels. The operational changes are expected to cause lead emissions to decline by 91 percent. Due to limitations in air modeling, it was not possible to make future predictions for Paccha and Huari. There is some uncertainty regarding the extent of decline in soil and dust lead concentrations relative to the decline in air emissions. It is assumed that soil concentrations are heavily influenced by historical emissions and are not likely to decline dramatically in the short term. It is also believed that declines in dust lead concentrations will be limited by soil concentrations, as windblown soil contributes to dust. Considering these limitations, the predicted annual mean concentration for La Oroya Antigua is 15μg/dL, with 98 percent of children there expected to have blood lead concentrations above 10 μg/dl. In La Oroya Nueva, blood lead levels in 39 percent of children are expected to remain above the CDC level of concern; the prediction for Marcavalle/Chucchis is 7 percent. The USEPA risk target for lead exposure in children is 5 percent; in other words, the probability that a child s blood lead concentration would exceed 10 μg/dl should be no greater than 5 percent. Based on the ISE model, it is expected that all communities surrounding the Complex will continue to exceed this risk target, meaning that many of the children in the region are at risk for neurobehavioral changes and effects on the body s ability to make heme, a vital ironcarrying pigment in blood. Many of these effects are subtle and cannot be easily attributed to lead exposures in an individual child. The effects of lead may also be confounded by other factors such as poor nutrition and iron deficiency anemia. The effects of altitude must also be considered when evaluating risk in this population. Natural increases in hemoglobin levels of high altitude populations cause higher blood lead levels relative to body burden. Integral Consulting Inc. xxii

23 Blood lead levels in adults have also shown a marked decrease compared with the 2005 risk assessment. Data collected in 2007 from pregnant women showed a mean blood lead level of 7 μg/dl for La Oroya Antigua, compared with 17 μg/dl in Fetal blood lead levels can be calculated from maternal levels and compared with the CDC level of concern. In 2004, there was an 86 percent probability that a fetus blood lead concentration would exceed 10 μg/dl in La Oroya Antigua. In 2007, the probability dropped to 18 percent. After 2009, it is predicted that the mean maternal blood lead level in La Oroya Antigua will be 5.4 μg/dl, with a 5 percent probability that a fetus blood will exceed 10 μg/dl. Other communities show even lower levels for 2007 and Because of limitations in the design of the adult blood lead model, greater uncertainty is associated with predictions of future adult blood lead levels than with children s. Relative contributions from different media (soil, dust, air, water, and diet) to total exposure were assessed using the children s blood lead model. Outdoor dust is currently the largest contributor to exposure in all communities, ranging from 38 percent in Paccha to 56 percent in La Oroya Antigua. As emissions from the smelter decline, the relative contribution is expected to shift so that soil becomes a larger contributor to overall exposure. This trend can be observed by comparing the 2004 modeling results to the 2007 results. In 2004, soil contributed 5 percent of exposure in La Oroya Antigua compared with 12 percent in After 2009, the percent contribution is expected to be 17 percent. As soil becomes a more prominent exposure pathway, future declines in blood lead levels will be limited by residual lead concentrations in soil. CANCER RISK ESTIMATES Cancer risks for non lead metals included in this risk assessment were estimated for ingestion of arsenic in soil, dust, and drinking water, and for inhalation of arsenic and cadmium in the air. Arsenic was detected only infrequently in drinking water samples but exceeded regulatory limits established by the Superintendencia Nacional de Servicio de Saneamiento (SUNASS) in four samples from La Oroya Antigua.. Risk estimates calculated for these samples exceeded the USEPA acceptable cancer risk range, but were not added to other risk estimates because the origin of arsenic in these samples was not clear. Because of limitations in the air dispersion model, cancer risk estimates for predicted future exposures after 2009 were developed only for La Oroya Antigua, La Oroya Nueva, and Marcavalle/Chucchis. Combined cancer risks for incidental ingestion of arsenic in indoor dust, outdoor dust, and soil are highest for La Oroya Antigua, with an upper end exposure risk estimate of 5 in 1,000 (5 x 10 3 ), and a typical or central tendency exposure risk estimate of 2 in 1,000 (2 x 10 3 ). In the other communities, risk estimates were lower, but still above USEPA s acceptable risk range. Many of these risk estimates have fallen slightly compared with those of the 2005 risk assessment. In all communities, the highest contribution to total cancer risk for oral exposure came from incidental ingestion of arsenic contained in outdoor dust. The contribution from indoor dust was lower than or in some cases equal to that from outdoor dust. The contribution from Integral Consulting Inc. xxiii

24 incidental ingestion of arsenic in surface soil was generally lower than that from outdoor dust, although its relative contribution was greater in 2007 than in After 2009, arsenic emissions from the Complex are expected to decline by 91 percent and cancer risk estimates for intake of arsenic via incidental ingestion of dust and soil are expected to decrease approximately 30 to 50 percent compared with current conditions. Except for risk estimates for typical exposures in La Oroya Nueva and Marcavalle/Chucchis, the future risk estimates remain above USEPA s range of acceptable cancer risks. For both typical and upperend exposures, the predicted contribution of outdoor and indoor dust to total risk after 2009 remains higher than that for soil. However, consistent with the expected reductions in arsenic emissions and arsenic concentrations in dust, the magnitude of difference between these exposure media (i.e., dust vs. soil) is not as great as under current conditions. As emissions from the Complex are reduced, the residual soil arsenic concentrations from historical operations will come to dominate exposures. Cancer risk estimates for inhalation of arsenic and cadmium in air under current conditions were greatest in La Oroya Antigua for both typical and reasonable maximum exposures. For La Oroya Antigua, the risk estimate for upper end exposures was 4 in 1,000 (4 x 10 3 ), while for typical exposures the risk estimate was 2 in 1,000 (2 x 10 3 ). In the other communities, inhalation risk estimates were lower, but still above USEPA s acceptable risk range. All of these risk estimates have fallen compared with those from the 2005 risk assessment; in 2005 La Oroya Antigua had the highest risk estimate for both upper end and typical exposures at 2 in 100 (2 x 10 2 ) and 5 in 1,000 (5 x 10 3 ), respectively. Risks contributed by inhalation of arsenic are generally about 100 times as great as those of cadmium. Estimates of cancer risks for inhalation of arsenic and cadmium after 2009 are dramatically reduced from current conditions and most of them fall within the upper end of USEPA s acceptable cancer risk range. The highest risk estimate, 8 in 100,000 (8 x 10 5 ), is for u pper-end exposures in La Oroya Antigua. Estimates of risk for typical exposures in these communities and both upper-end and typica exposures in Marcavalle/Chucchis are within USEPA s acceptable risk range. CHARACTERIZATION OF NONCANCER RISKS Noncancer health risk estimates for all communities were calculated for both current exposures and predicted exposures after Ingestion exposures were assessed for arsenic, cadmium, antimony, and copper in indoor dust, outdoor dust, and surface soil. Drinking water ingestion exposures were assessed for arsenic and antimony. Inhalation exposures were assessed for arsenic, antimony, and cadmium. For drinking water, as described above, arsenic was detected in four samples from La Oroya Antigua, with a maximum arsenic concentration of mg/l, 2.5 times the SUNASS limit. Integral Consulting Inc. xxiv

25 There is no SUNASS limit for antimony, which was detected in only two samples at the detection limit of 0.01 mg/l. Hazard indices for arsenic in drinking water are 3 for the central tendency exposure and 7 for the upper end exposure. For antimony, the comparable hazard indices are 0.9 and 2. These hazard indices were not added to those for dust and soil because the origin of the drinking water supplies and potential impacts from the Complex on the supplies are not clear. Current noncancer risk estimates for ingestion of dust and soil combined were highest for arsenic, with hazard indices exceeding 1 in all communities. Hazard indices for typical exposures were 9 in La Oroya Antigua, and 1 to 3 in the other communities. Hazard indices for upper end exposures were 20 in La Oroya Antigua, and 4 to 10 in the other communities. Noncancer risk estimates were below levels of concern for all other metals in all communities, with the exception of upper end exposures to antimony in La Oroya Antigua (hazard index of 3). Given the magnitude of risks associated with chronic exposure to arsenic within these communities, risks associated with shorter term (i.e., subchronic) exposures were assessed for young children. Exposures of children 0 to 6 years old from incidental ingestion of outdoor dust, indoor dust, and surface soil were compared with an arsenic subchronic reference dose. Hazard indices for upper end exposures were 4 for a child residing in La Oroya Antigua and 2 for a child residing in Marcavalle/Chucchis. In La Oroya Nueva, Santa Rose de Saco/Huaynacancha, Paccha and Huari, hazard indices were less than 1, indicating that subchronic noncancer risks due to arsenic in these communities are not of concern. Noncancer ingestion risks are predicted to drop dramatically after Predictions were made for exposures to arsenic and cadmium in La Oroya Antigua, La Oroya Nueva, and Marcavalle/Chucchis. The predicted hazard index for upper end exposures for arsenic in La Oroya Antigua is 5 (compared with 20 for current conditions). After 2009, soil (hazard index of 3) is predicted to make the greatest contribution to arsenic exposures. Hazard indices for arsenic in other communities were 2 or less. For cadmium, all predicted hazard indices are much less than 1. Current noncancer risk estimates were also calculated for inhalation of arsenic, cadmium, and antimony. Arsenic yielded the highest risk estimates for current exposures. In La Oroya Nueva and La Oroya Antigua the hazard indices were 40 for the typical exposures and 60 for the upper end exposures. In Marcavalle/Chucchis, the hazard indices were 20 for the typical exposures and 30 for the upper end exposures. In Huari, Paccha, and Santa Rosa de Sacco/Huaynacancha, hazard indices ranged from 8 to 10 for typical exposure conditions and from 10 to 20 for upper end exposures. Hazard indices for cadmium were 2 or less in all communities, indicating very limited risks. Cadmium risks have declined significantly since the 2005 assessment. Antimony upper end Integral Consulting Inc. xxv

26 exposure hazard indices ranged from 4 to 6 in La Oroya Nueva, La Oroya Antigua, and Marcavalle/Chucchis, and those for typical exposures from 2 to 4. In Huari, Paccha, and Santa Rosa de Sacco/Huaynacancha, antimony hazard indices were all 3 or less. Future noncancer inhalation risks are predicted to drop dramatically after Predicted arsenic hazard indices range from 0.4 to 1 and cadmium hazard indices from 0.1 to 0.3. CONSIDERATION OF MIXTURES OF CHEMICALS Chemicals in mixtures can interact to either increase or decrease overall health effects. For mixtures of carcinogenic chemicals, standard risk assessment practice is to assume that risks are additive. Assessment of mixtures is a developing area of toxicology that is not fully understood, and the USEPA guidance for risk assessment of mixtures does not yet provide consistent methods for quantitative analysis of effects other than cancer. The potential for significant interactions among chemicals in La Oroya is great because of the high levels of exposure and the similarity of potential effects. While possible interactions in La Oroya cannot be quantified, it is very important to understand the multiple factors that may contribute to the primary health effects and to account for them in any future health studies. To that end, the risk assessment includes a review the principal expected health effects and their contributing factors, including the impacts of mixtures of particulate matter and sulfur dioxide on the lung; possible interactions of lead, arsenic, cadmium and iron deficiency on anemia; and possible interactions among poor nutritional status, lead, cadmium, and alcohol on bone. UNCERTAINTY EVALUATION As described above, risk assessments predict the likelihood of health effects in a population, but do not directly measure the occurrence of health effects. The predicted risks are based on many assumptions about the ways that people come into contact with chemicals in the environment. Although many of these assumptions are based on scientific studies and site specific data, uncertainty remains regarding how well the available data reflect the ways residents are actually exposed to chemicals. The degree of confidence in the results of a risk assessment depends on how closely the data and assumptions used match actual conditions. In general, where uncertainties existed, conservative parameters, assumptions, and methodologies were used to enhance the likelihood that potential exposures and risks would not be underestimated. It is important that the uncertainty be evaluated in the context of the intended scope of the risk assessment. The goals of this risk assessment were to evaluate current human health risks in the community due to air emissions from the Complex and to predict changes in future health risks as smelter emissions are reduced. Evaluation of current health risks focused on characterizing the ways people are exposed to Complex air emissions and the relative Integral Consulting Inc. xxvi