HUMAN HEALTH RISK ASSESSMENT OF EMISSIONS FROM THE MILLERHILL RECYCLING AND ENERGY RECOVERY CENTRE

Transcription

1 APPLICATION FOR A PERMIT TO OPERATE A PART A INSTALLATION UNDER THE POLLUTION PREVENTION AND CONTROL (SCOTLAND) REGULATIONS 2012 HUMAN HEALTH RISK ASSESSMENT OF EMISSIONS FROM THE MILLERHILL RECYCLING AND ENERGY RECOVERY CENTRE Prepared for: FCC ENVIRONMENT, MILLERHILL, MIDLOTHIAN ECL Document Reference P2154/R009 Prepared by: Environmental Compliance Limited Unit G1, The Willowford, Main Avenue, Treforest Industrial Estate, Pontypridd CF37 5YL

2 HUMAN HEALTH RISK ASSESSMENT OF EMISSIONS FROM THE MILLERHILL RECYCLING AND ENERGY RECOVERY CENTRE FCC ENVIRONMENT, MILLERHILL, MIDLOTHIAN Report Reference Number: Report Issue: Report Prepared by: P2154/R009 Final Report Reviewed & Approved by: Name: Sarah Burley Name: Howard Ling Signature: Signature: Date: Date: This report is not to be used for contractual or engineering purposes unless this approval sheet is signed where indicated by both the originator of the report and the approver and the report is designated "FINAL. This report has been prepared by Environmental Compliance Limited (ECL) in their professional capacity as Environmental Consultants. The contents of the report reflect the conditions that prevailed and the information available or supplied at the time if its preparation. The report, and the information contained therein, is provided by ECL solely for use and reliance by the Client in performance of ECL s duties and liabilities under its contract with the Client. The contents of the report do not, in any way, purport to include any manner of legal advice or opinion. P2157/R009 i

3 HUMAN HEALTH RISK ASSESSMENT OF EMISSIONS FROM THE MILLERHILL RECYCLING AND ENERGY RECOVERY CENTRE FCC ENVIRONMENT, MILLERHILL, MIDLOTHIAN TABLE OF CONTENTS Section Page 1. INTRODUCTION BACKGROUND SCOPE OF WORKS 1 2. EXISTING CONDITIONS LIFE EXPECTANCY 3 3. RISK ASSESMENT - METHODOLOGY OVERVIEW OF RISK ASSESSMENT APPROACH TO RISK ASSESSMENT METHODOLOGY FOR ESTIMATING EXPOSURE TO COPCS 5 4. STEP 1: DEFINE THE LEGISLATIVE CONTEXT INTRODUCTION POLLUTION PREVENTION AND CONTROL PERMIT PLANNING APPLICATION 7 5. STEP 2: HAZARD IDENTIFICATION INTRODUCTION SITE SPECIFIC CONCEPTUAL MODEL ( SSCM ) POTENTIAL EXPOSURE PATHWAYS PATHWAYS RELEVANT TO THE PROPOSED INSTALLATION RECEPTORS ESTIMATION OF COPC CONCENTRATION IN MEDIA STEP 3: HAZARD ASSESSMENT INTRODUCTION SOURCES OF DIOXINS AND FURANS STEP 4: RISK ESTIMATION ASSESSMENT CRITERIA ASSUMPTIONS RISK ESTIMATION RESULTS STEP 5: RISK EVALUATION SUMMARY OF EXPOSURE ASSESSMENT STEP 6: RISK MANAGEMENT RISK MANAGEMENT MEASURES 37 P2157/R009 ii

4 LIST OF APPENDICES APPENDIX 1 APPENDIX 2 Figures Site Specific Parameters P2157/R009 iii

5 1. INTRODUCTION HUMAN HEALTH RISK ASSESSMENT OF EMISSIONS FROM THE MILLERHILL RECYCLING AND ENERGY RECOVERY CENTRE 1.1. Background A human health risk assessment ( HHRA ) has been undertaken to provide information in support of the planning and environmental permit applications for the proposed Millerhill Recycling and Energy Recovery Centre ( RERC ) at Millerhill, Midlothian, to be operated by FCC Environment ( FCC ) The study has been carried out in accordance with guidance published by the Scotland and Northern Ireland Forum for Environmental Research ( SNIFFER ). This guidance document sets out six stages for a risk assessment study: Step 1: Define the legislative context Step 2: Hazard identification Step 3: Hazard assessment Step 4: Risk estimation Step 5: Risk evaluation Step 6: Risk management 1.2. Scope of Works This assessment evaluates the possible effects on the health of the local human population likely to be exposed to emissions from the proposed RERC. The geographic scope of the study is based on the same area which covers all the sensitive receptors that were used in the air dispersion modelling study, namely a 10km by 10km grid using the main discharge stack as a central point Given that the assessment is related to exposure through the direct inhalation of affected air and indirect exposure through ingestion of affected food and locally grown produce on soil which may be affected by the deposition and accumulation of emissions from the proposed facility, the only emissions relevant to the assessment are those arising from the facility s main discharge stack. Fugitive emissions are not considered relevant to this assessment The substances emitted from the stack - termed hereafter the contaminants of potential concern COPCs - can be considered under the following categories: P2157/R009 1 substances for which any effects are more likely to be acute, and which tend to occur shortly after exposure; these substances can be subdivided into two groups:

6 (i) (ii) acid gases, such as sulphur dioxide, nitrogen dioxide, hydrogen chloride and hydrogen fluoride; and other substances, such as carbon monoxide and fine particulate matter. substances for which any effects are likely to be chronic, and which tend to arise from prolonged exposure; these substances can also be subdivided into two groups: (i) (ii) heavy metals; and semi-volatile and non-volatile organic chemicals, specifically dioxins and furans and dioxin-like PCBs AQSs have been assigned for the majority of the COPCs listed above and, accordingly, the risks to human health from these have been assessed as part of the associated atmospheric dispersion modelling study. The assessment concluded that there were no significant impacts from these COPCs, and accordingly, no further assessment is considered necessary. Consequently, only dioxins and furans, have been subject to the full USEPA HHRAP methodology (see Section of this document) The assessment has evaluated potential impacts on human health from potential dioxin emissions, both in terms of the long-term inhalation, and the overall long-term exposure through additional viable routes such as the food chain In accordance with the recommended UK tiered approach to risk assessment, the HHRA has considered worst-case scenarios for all receptors in assuming multiple exposure conditions where all pathways of exposure in each land use scenario were considered to be viable. Some of these assumptions are both extremely conservative and also very unlikely, and, therefore, the assessment is likely to over-estimate any potential impacts In relation to the cumulative effects, it is known that, at the time of writing, that potential developments within a 15km radius that should be considered in a cumulative assessment are the neighbouring Alauna Renewable Energy ( ARE ) Anaerobic Digestion facility located to the north of the site and the proposed new gas fired Cockenzie Power Station, which has planning permission The ARE facility emits only NOx, SO2 and CO and accordingly does not need to be considered as part of the dioxins and furans assessment The proposed location of the Cockenzie Power Station is only one of a number of options for the site and no permit application discussions have taken place with SEPA. SEPA have therefore confirmed that the Power Station is not required to be included in the assessment. P2157/R009 2

7 2. EXISTING CONDITIONS 2.1. Life Expectancy The life expectancy of people living in Midlothian in is higher than the life expectancy of Scotland as a whole. For example, the life expectancy of women at birth in Midlothian is 81.4 whereas in Scotland the equivalent is For men the Scottish life expectancy at birth is 76.8, but in Midlothian the life expectancy at birth is Since 1998 there has been a steady rise in life expectancy in Scotland and Midlothian, however the rate of increase in life expectancy is significantly more in women then men The life expectancy at birth of Edinburgh can also be considered due to the proximity of the Millerhill RERC to the City. For central Edinburgh, the life expectancy at birth between years is 77.5 for men and 81.8 for women, both of which are higher than the national average. P2157/R009 3

8 3. RISK ASSESMENT - METHODOLOGY 3.1. Overview of Risk Assessment The study has been carried out in accordance the six stages of risk assessment described in Section of this document, namely: Step 1: Define the legislative context Step 2: Hazard identification Step 3: Hazard assessment Step 4: Risk estimation Step 5: Risk evaluation Step 6: Risk management For the assessment and evaluation, detailed computer modelling has been undertaken. The basis for the HHRA is predictive modelling using the ADMS Version 5 atmospheric dispersion model to estimate the likely ground level concentrations of COPCs and deposition rates for dioxins and furans as a result of emissions from the proposed installation The methodology for the assessment of dioxin and furan is based on the USEPA HHRAP (see Section of this document) The Industrial Risk Assessment Program - Human Health (IRAP-h View Version ), which is based on the USEPA HHRAP, has been used to calculate the transport and fate of dioxins and furans emitted from the RERC main discharge stack The geographical area considered in the HHRA, together with the locations of the various sources, is indicated in Figure 2157/F2 in Appendix Approach to Risk Assessment The approach taken by the IRAP-h View software, which accords with that set out in guidance, seeks to quantify the hazard faced by the receptor- the exposure of the receptor - to the substance identified as being a potential hazard and then to assess the risk of exposure, as follows: (i) Quantification of the exposure - an exposure evaluation that determines the dose and intake of key indicator chemicals for an exposed person. The dose is defined as the amount of a substance contacting the body (e.g. in the case of inhalation - the lungs) and intake is the amount of the substance absorbed into the body. The evaluation is based on, worst case, conservative scenarios, with respect to the following: location of the exposed individual and duration of exposure; exposure rate; and P2157/R009 4

9 (ii) emission rate from the source. Risk characterisation - following quantification of the exposure, the risk is characterised by examining the toxicity of the substances to which the individual has been exposed and evaluating the significance of the calculated dose in the context of probabilistic risk Methodology for Estimating Exposure to COPCs In order to estimate exposure from the emissions from the facilities considered in the assessment, the following steps have been undertaken: (i) (ii) measurement or estimation of emissions from the source - in the case of the proposed facility, emissions have been based on the relevant emission limit values ( ELVs ), and, therefore, are likely to be an overestimate of the actual emissions; modelling the fate and transport of the emitted substances through the atmosphere and through soil, water and biota following deposition onto land.; atmospheric dispersion modelling has been undertaken using ADMS 5 (see ECL Report P2184/R008); concentrations of the COPCs in the environmental media are estimated at the point of exposure, which may be through inhalation or ingestion. (iii) calculation of the uptake of the emitted substances into humans coming into contact with the affected media and the subsequent distribution in the body; this element of the assessment us undertaken using IRAP-h View (see Section of this document) With regard to Step (iii), the exposure assessment considers the uptake of dioxins and furans, by various categories of human receptors (resident/farmer/fisher). It should be noted that IRAP-h View does not have a category for a workplace receptor therefore the resident receptor parameters have been adjusted appropriately, for example a for a school the exposure time would be restricted to 8 hours per day, 5 days a week and 38 weeks a year. P2157/R009 5

10 4. STEP 1: DEFINE THE LEGISLATIVE CONTEXT 4.1. Introduction This human health risk assessment is provided in to support both the planning and PPC Permit application for the Millerhill RERC The legislative context was defined in terms of the planning and permitting regimes, and associated guidance published by the Scottish Environmental Protection Agency ( SEPA ) for use in the permitting process The study has been carried out in accordance with guidance published by SNIFFER 1.. This guidance document sets out six stages for a risk assessment study: Step 1: Define the legislative context Step 2: Hazard identification Step 3: Hazard assessment Step 4: Risk estimation Step 5: Risk evaluation Step 6: Risk management 4.2. Pollution Prevention and Control Permit In order for the RERC to operate it must obtain a permit to operate under the Pollution Prevention and Control (Scotland) Regulations 2012 ( PPC Regulations ). The PPC Regulations implement the requirements of the Directive on industrial emissions (integrated pollution prevention and control (Recast) (Directive 2010/75/EU), which is generally referred to as the Industrial Emissions Directive ( IED ) The main purpose of the permitting process as a whole is to prevent emissions where practicable. Where this is not possible, a high level of environmental protection should be demonstrated. This study will demonstrate that the impact of emissions from the RERC on human health is acceptable As SEPA does not prescribe any particular assessment for Step 4: Risk Estimation, methods for permit applications for these types of processes typically follow either the approach developed by Her Majesty s Inspectorate of Pollution ( HMIP ) - Risk Assessment of Dioxin releases from Municipal Waste Incinerators (1996) approach or the United States Environmental Protection Agency ( USEPA ) Human Health Risk Assessment Protocol ( HHRAP ) for Hazardous Waste Combustion Facilities (EAP530-R , September 2005) approach. For this assessment the US EPA HHRAP methodology has been used. 1 Scotland and Northern Ireland Forum for Environmental Research., Environmental Legislation and Human Health: guidance for assessing risk, P2157/R009 6

11 4.3. Planning Application The National Planning Policy Framework for Scotland 3 describes the responsibilities of local planning authorities to contribute to sustainable development, and emphasises that this includes the implementation of policies designed to protect public health. It states that, Sustainable economic and social development depend on healthy terrestrial and marine environments. Furthermore, it states that the main elements of the spatial strategy to 2030 are to.. promote development which helps to improve health, regenerate communities and enable disadvantaged communities to access opportunities This study, and the associated air dispersion modelling study have demonstrated that there will be emissions to air as a result of the operation of the RERC, although it should also be noted that the RERC will reduce reliance on landfill and will increase recycling rates and indirectly be of benefit to human health. Planning guidance is therefore interpreted, in this context, to mean that emissions to air from the proposed facility should have no significant adverse effects on health, which is in accordance with SEPA guidance. P2157/R009 7

12 5. STEP 2: HAZARD IDENTIFICATION 5.1. Introduction Hazard identification aims to identify contaminants of concern, their distribution in the different media and consequently to which relevant receptors are exposed. As there are no recognised UK protocols for estimating the level of human exposure to COPCs through all relevant pathways of exposure (see Section 5.3. of this document), the USEPA HHRA was used to estimate all exposures using the predicted air concentration and depositions rates provided by the air dispersion modelling study undertaken using ADMS Hazard identification 2 comprised an identification of the substances of potential concern; consideration of how they could be released and transferred into the environment; and identification of those who could potentially be affected by these hazards A site specific conceptual model ( SSCM ) of the hazards, based on the sourcepathway-receptor, concept has been produced. The SSCM provides an indication of the: principal hazards sources on the site: i.e. the point source emissions from the RERC stack;; COPCs; behavior of COPCs in the identified media, considering potential exposure via airborne pathways, deposition on soils, uptake by home grown vegetables and other agricultural products, uptake by animals and uptake by humans; potential sensitive receptors; pathways connecting the COPCs and sensitive receptors Site Specific Conceptual Model ( SSCM ) The development of a SSCM is used to identify the potential sources, critical pathways and receptors that require assessment and is provided in Figure 1. 2 Note: Hazard Identification for this HHRA relates to hazards identified from emissions to air only. P2157/R009 8

13 Figure 1: Site Specific Conceptual Model The source of the emissions is a 75m high discharge stack from the energy from waste plant located within the RERC. The COPCs which are emitted are as follows: particulate matter; sulphur dioxide; carbon monoxide; oxides of nitrogen (expressed as nitrogen dioxide); ammonia; hydrogen chloride; hydrogen fluoride; volatile organic compounds ( VOCs, expressed as total organic carbon; mercury; P2157/R009 9

14 cadmium; thallium; antimony; arsenic; chromium; cobalt; copper; lead; manganese; nickel; vanadium; polyaromatic hydrocarbons ( PAH ) as benzo-a-pyrene; polychlorinated biphenyls ( PCBs ); and dioxins and furans As previously indicated in Section of this document, the risks to human health from the majority of these pollutants have been assessed as part of the associated atmospheric dispersion modelling study, therefore, no further assessment is considered necessary. Accordingly, only dioxins and furans, have been subject to the full USEPA HHRAP methodology (see Section of this document) Potential Exposure Pathways The following pathways were considered as part of the assessment: inhalation (including acute inhalation); ingestion of soil; consumption of fruit and vegetables; consumption of poultry and eggs; consumption of meat (beef, pork and fish); consumption of cow s milk and human breast milk; and consumption of drinking water Members of the local population are only likely to be exposed to significant effects associated with emission of dioxins and from the proposed installation if: they spend significant periods of time at locations where and when emissions from the proposed installation increase the concentration of dioxins/furans above the existing background concentration; they consume food grown at locations where emissions increase the concentration of dioxins/furans above the concentration normally present in food from those locations; they undertake activities likely to lead to ingestion of soils at locations where emissions have increased the concentration of dioxins/furans in the soil above background levels; and they drink water from sources exposed to increased concentrations of dioxins/furans above the levels normally present. P2157/R009 10

15 The extent of exposure that any person may experience will depend directly on the degree to which they engage in any or all of the above activities, and by how much the existing background concentration of dioxins/furans increases as a result of the operation of the proposed installation. The drinking water pathway is considered to be highly unlikely as very few people are likely to collect and drink rainwater in the vicinity of the site Pathways Relevant to the Proposed Installation Inhalation People living and working in close proximity to the proposed installation may, potentially, be exposed to marginally higher levels of dioxins/furans as result of the operation of the proposed installation for the proportion of time they spend there. Consequently, this pathway is considered relevant to this assessment Ingestion of Soil People working on the land in close proximity to the proposed facility may be exposed to, potentially, marginally higher levels of dioxins/furans are as result of the operation of the proposed installation for the proportion of time they work there. Given the predominantly industrial location of the proposed installation, the potential for exposure is likely to be limited to a few individuals who work on the adjacent land (i.e. any farmland and landscaped areas), and those local residents who may tend to plots on their own gardens or allotments. Consequently, this pathway is considered relevant to this assessment Consumption of Fruit and Vegetables It is likely that the majority of people purchase their fruit and vegetables from commercial outlets which are likely to source their produce from outside the locality. Unless a substantial proportion of fruit and vegetables sold are produced locally, the majority of the local population s exposure to dioxins/furans will not be affected by the operation of the proposed installation People who consume fruit and vegetables grown in the vicinity of the proposed installation may, potentially, be exposed to marginally higher levels of dioxins/furans, although any increase is likely to be small compared with existing exposures. The likelihood of individuals obtaining almost all of their fruit and vegetable consumption from gardens and allotments is likely to be low. Nevertheless, this pathway is considered relevant to this assessment as the situation could change in the future Consumption of Poultry and Eggs Free-range poultry may, potentially, be exposed to dioxins/furans through soil ingested with food picked up from the ground. It is not known if rearing of free-range poultry occurs to a significant level in the vicinity of the proposed installation, however a future scenario might see a change in land use that could be used for P2157/R009 11

16 rearing chickens. Therefore, the consumption of chicken and eggs could be a potential exposure scenario in the future and consequently, this pathway is considered relevant to this assessment Consumption of Meat As with free-range poultry, pigs and cattle may, potentially, be exposed to dioxins/furans through soil ingested with food picked up from the ground. It is not known if rearing of these animals occurs to a significant level in the vicinity of the proposed installation, however, a future scenario might see a change in land use associated with rearing of pigs and cattle. Therefore, the consumption of meat could be a potential exposure scenario in the future and consequently, this pathway is considered relevant to this assessment It should be noted that not all exposure scenarios will result in the ingestion of homegrown meat and animal products and these food products are only considered by the IRAP-h View for farmers and for families of farmers Consumption of Fish It should be noted that as with the ingestion of meat, not all exposure scenarios will result in the ingestion of fish. The ingestion of fish is only considered where there is a local water body that is used for fishing and where the diet of the fisher (and family) may be regularly supplemented by food caught from these local water sources There are some watercourses in proximity to the proposed installation, including the Firth of Forth. It is understood some of these water courses can be used for fishing. However, it is not known whether fish caught are returned to the water or kept for consumption, but for the purposes of this assessment, it has been assumed that such fish could be consumed. Consequently, consumption of fish is considered relevant to this assessment It should be noted that not all exposure scenarios will result in the ingestion of fish, therefore fish are only considered by the IRAP-h View for fishers and for families of fishers Consumption of Cow s Milk It is possible that dairy herds may, potentially, be exposed to dioxins/furans through soil ingested with their food. It is unlikely that people living in residential locations would rear cows and consequently consume cow s milk. Therefore, consumption of cow s milk is only considered for the farm receptors It is not known whether any of the farms in the vicinity of the proposed installation are dairy farms, therefore, using a precautionary approach, the consumption of cow s milk is considered relevant for all farms assessed. P2157/R009 12

17 Consumption of Human Breast Milk Babies may, potentially, be exposed to dioxins/furans via ingestion of contaminated breast milk. The potential for contamination of breast milk is especially high for dioxin-like compounds which are highly lipophilic and are likely to accumulate in breast milk. The mother may, potentially, be exposed to dioxins/furans and dioxinlike PCBs via the inhalation or ingestion pathways. Consequently, consumption of breast milk is considered relevant to this assessment Drinking Water Potential exposure through the ingestion of drinking water requires contamination of the local drinking water sources. There are no major aquifers or drinking water reservoirs within the vicinity of the site. It is not known if there are potable surface water abstraction points in the area surrounding the proposed installation. Consequently, again using a precautionary approach, this pathway has been included for the purposes of this assessment Receptors Exposure setting characterisation is generally limited to the assessment area that is defined by a 10-km radius (taken from the centre of the discharge stack location). This radius is a generally recognised and acceptable limit for the air dispersionmodelling domain. However, USEPA guidance on HHRA recommends that resources for characterising the exposure setting should initially be focused on the areas surrounding the emission sources and extending out to about 1.5 km, where the most significant deposition has been generally observed. For this assessment a 10km by 10km area was utilised to ensure consistency with the air dispersion model as this area will cover the locations of all sensitive human receptors The purpose of characterising the exposure setting is to identify current human activities or land uses that provide the basis for evaluation of recommended exposure scenarios that may result due to exposure to emissions from one or more emission sources IRAP-h View allows the digitisation of areas of concern where risk receptors and exposure scenarios can be selected for evaluation. Once an area has been defined, the model identifies, within each of the specified areas, all the grid nodes with the highest yearly averages for each modelled air parameter (e.g., air concentration, dry deposition, wet deposition) for each phase (e.g., vapour, particle, particle-bound) to each emission source. This will result in the selection of one or more receptor grid nodes as the location of one or more exposure scenario locations that meet the following criteria: highest vapour phase air concentration; highest vapour phase dry deposition rate; highest vapour phase wet deposition rate; highest particle phase air concentration; P2157/R009 13

18 highest particle phase dry deposition rate; highest particle phase wet deposition rate; highest particle-bound phase air concentration; highest particle-bound phase dry deposition rate; and highest particle-bound phase wet deposition rate The locations of potentially sensitive receptors are indicated in Figure 2154/F2 (see Appendix 1 of this document) The thirty-four human receptors used in the air dispersion modelling study were also used in the assessment and are provided in Table 1. Table 1 Ref Sensitive Human Receptors Used in the HHRA Location Scenario Resident Easting Northing Distance from Source (m) Heading (degrees) R1 Stoneyhill Primary School R2 Whitehill R3 Queen Margret University Halls R4 Stoneybank R5 Queen Margaret University R5 Whitecraig Primary School R7 Old Craighall Village R8 Wellington Farm R9 Newton House R10 Dalkeith High School R11 Old Craighall Road R12 Shawfair Area (existing) R13 Shawfair Area (existing) R14 Shawfair Area (existing) R15 Shawfair Area (existing) R16 Lowe's Fruit Farm R17 Newton Village R18 Spire Shawfair Hospital R19 Newton Village R20 Millerhill Road - west R21 Danderhall R22 Danderhall Primary School R23 Hilltown R24 Millerhill Road - east Farmer Fisher P2157/R009 14

19 Table 2 Sensitive Human Receptors Used in the HHRA Scenario Ref Location Resident Farmer Fisher Easting Northing Distance from Source (m) Heading (degrees) R25 Shawfair Area (existing) R26 Edinburgh Royal Infirmary R27 Shawfair (within new development) R28 Cauldcoats R29 Greengables Nursery School R30 Redcroft R31 Whitehill Mains R32 Newcraighall Town R33 New Craighall Primary School R34 Royal Hospital for Sick Children Estimation of COPC Concentration in Media The IRAP-h View model used for the assessment is equipped with a database of physical and chemical parameters used to calculate the media concentrations for all relevant COPCs. These are chemical specific values based on current international knowledge In addition to the default values, which were used for this assessment, site-specific data are required for some of the parameters. These include the following: annual average evapotranspiration; annual average irrigation; annual average precipitation; annual average runoff; and annual average wind velocity The site specific data used for the Millerhill area is as follows: annual average precipitation = cm/year (average value taken from meteorological data used in the air dispersion modelling report); annual average runoff = cm/year (from Defra for Scotland runoff is 73% of rainfall) ; annual average irrigation = 6.19 cm/year (irrigation = (precipitation runoff) x 1/3); P2157/R009 15

20 annual average evapotranspiration = cm/year (evapotranspiration =(precipitation runoff) x 2/3); annual average wind velocity = 4.29 m/s (average value taken from meteorological data used in the air dispersion modelling report). annual average air temperature = 9. o C (average value taken from meteorological data used in the air dispersion modelling report) Calculation of COPC Air Concentration for Direct Inhalation Air concentrations used to calculate direct inhalation of COPCs risks are characterised as the total of vapour and particle air concentrations inhaled. Two calculations are performed, one to evaluate the long term or chronic exposure and the other to evaluate the short term or acute exposure Calculation of COPC Concentrations in Soil COPC concentrations in the soil are calculated by summing the particle and vapour phase deposition of COPCs to the soil. Following deposition, COPCs may be incorporated into the upper layers of the soil where produce is grown The calculation of soil concentration incorporates a term that accounts for the loss of COPCs by several mechanisms, including leaching, erosion, runoff, degradation (biotic and abiotic) and volatilisation. All these mechanisms will result in a lowering of the soil concentration associated with the deposition rate Soil conditions, such as ph, structure, organic matter content and moisture content, affect the distribution and mobility of COPCs. Loss of COPCs from the soil is modelled by using rates that depend on site-specific data about the physical and chemical characteristics of the soil Calculation of COPC Concentrations in Produce Indirect exposure, resulting from the ingestion of produce, depends on the total concentration of COPCs in the leafy and fruit portions of the produce. Produce can be contaminated by three mechanisms, namely: particle deposition - wet and dry deposition of particle-bound COPCs on the leaves and fruit of plants; vapour transfer - the vapour phase uptake of plants through their foliage; and root uptake - the root uptake of COPCs available from the soil and their transfer to the portions of the plant The sum of contamination occurring through all three of these mechanisms will result in the total COPC concentration in produce. P2157/R009 16

21 Calculation of COPC Concentrations in Beef and Dairy COPC concentrations in beef tissue and milk produced are estimated on the basis of the amount of COPCs that the cattle are assumed to eat in their diet. Cattle s diet is assumed to consist of forage (pasture and hay), silage and grain Further consumption of COPCs may occur through the cattle s ingestion of soil. The COPC concentration in the feed (forage and silage) is calculated as a sum of contamination occurring through the following mechanisms: particle deposition - wet and dry deposition of particle-bound COPCs on plants; vapour transfer - the vapour phase uptake of plants through their foliage; and root uptake - the root uptake of COPCs available from the soil and their transfer to the portions of the plant The potential for grain contamination is assumed to occur through root uptake only Calculation of COPC Concentrations in Pork COPC concentrations in pork are estimated on the basis of the amount of COPCs that the pigs are assumed to eat in their diet. A pigs s diet is assumed to consist of silage and grain Further consumption of COPCs may occur through the pigs s ingestion of soil. The COPC concentration in the silage is calculated as a sum of contamination occurring through the following mechanisms: particle deposition - wet and dry deposition of particle-bound COPCs on plants; vapour transfer - the vapour phase uptake of plants through their foliage; and root uptake - the root uptake of COPCs available from the soil and their transfer to the portions of the plant The potential for grain contamination is assumed to occur through root uptake only Calculation of COPC Concentrations in Poultry Meat and Eggs Estimates of COPC concentrations in poultry and eggs are based on the amount of COPCs that chickens are assumed to consume through their diet. The COPC route of exposure for chickens is assumed to be through soil and grain. Grain contamination is assumed to occur only through root uptake Other Parameters Site specific parameters for used for all receptors are presented in Appendix 2 of this document Quantifying Exposure Calculating COPC-specific exposure rates for each exposure pathway involves estimation of certain factors such as the media concentration and consumption rates. Consumption rates were estimated based on the recommendations and default values provided by the USEPA. The fraction of contaminated food stuffs consumed as a P2157/R009 17

22 fraction of the diet as whole was based on those provided in the HMIP methodology. This methodology does not provide data for a fisher scenario therefore the values quoted for a farmer were used. P2157/R009 18

23 6. STEP 3: HAZARD ASSESSMENT 6.1. Introduction The basis for the HHRA is predictive modelling using the ADMS Version 5 atmospheric dispersion model to estimate the likely ground level concentrations of all pollutants and deposition rates for dioxins and furans as a result of emissions from the proposed installation As indicated in Section of this report, those COPCs for which AQSs have been assigned have not been assessed further. An atmospheric dispersion modelling study (ECL Report Reference P2154/R008) was undertaken to assess the impact of releases from the proposed installation main discharge stack The study was undertaken using the ADMS modelling package, which is one of the models recognised by SEPA as being suitable for such studies. The study comprised two main elements: (i) the preliminary stack height screening assessment, the purpose of which was to determine a suitable stack height by modelling worst case emission scenarios for a range of stack heights; and (ii) the main modelling study, the purpose of which was to determine the impact of emissions from the proposed facility for the selected stack height The full modelling study report is provided separately. The results of the study in relation to the impact from the proposed installation only are presented in Section of report P2184/R008 and the assessment concludes that: releases from the proposed facility are considered unlikely to result in a breach of current air quality standards or have a detrimental effect on local human health. The assessment in relation to the cumulative impact of the proposed facility plus the ARE Facility are presented Section of P2184/R008 reaches the same conclusion Accordingly, from this point on, the assessment considered the impact of dioxins and furans only Sources of Dioxins and Furans For the purpose of assessing potential health impact associated with the effect of dioxin and furan emissions from the proposed facility, the RERC discharge stack is the only relevant emission source. Annex VI of the IED prescribes ELVs for emissions to air which are considered to be of relevance to long term exposure (chronic health effects). P2157/R009 19

24 The maximum GLCs of dioxins and furans at the location of the human sensitive receptors, was predicted using ADMS 5. IRAP-h View automatically extracts various air parameters from the air modelling plot-files and converts them into the required format. Air parameters generated by IRAP-h View include hourly air concentration from the particle phase, particle bound and vapour phase, annual average dry deposition from the particle phase, particle bound and vapour phase and annual average wet deposition from the particle phase, particle bound and vapour phase The air dispersion model considers dioxins as a single compound. However, the general term dioxins denotes a whole family of compounds based on two benzene rings fused to a central dioxin ring; in total, there are 75 individual dioxins, with each distinguished by the position of the chlorine atoms in the benzene rings. Furans - more correctly termed polychlorinated dibenzofurans ( PCDFs ) - are similar in structure to PCDDs, but in the case of PCDFs, the two benzene rings are fused to a central furan ring. The term furans also denotes a whole family of compounds, again, with each distinguished by the position of the chlorine atoms in the benzene rings Each individual dioxin and furan is referred to as a congener and each has different physical properties and toxicity levels which affect their atmospheric behaviour. The methodology used in IRAP-h View, therefore must consider the fate and transport of the dioxins and furans on a congener specific basis. It does this by accounting for the varying volatility of the congeners and their different toxicities For the purposes of the HHRA, only the seventeen congeners regarded as being the most hazardous are considered. The individual congeners have been assigned toxicity factors - International toxic equivalency factors ( I-TEFs ) - which are based on the toxicity of each of the seventeen congeners referenced to 2,3,7,8- tetrachlorodibenzodioxin ( 2,3,7,8-TCDD ), which is the most hazardous and is assigned an I-TEF of 1. The individual congener I-TEFs are used to convert individual congener concentrations in dioxin and furan emissions to a value known as the International Toxic Equivalent ( I-TEQ ) simply by multiplying the congener emission concentration by the relevant I-TEF. This provides a consistent means of assessing the toxicity of a mixture of dioxin and furan congeners. The sum of the I-TEQs for the individual dioxin and furan congeners forms the basis of the IED dioxin and furan ELV, which equates to 0.1ng/Nm 3 (expressed as the sum of the individual congener I- TEQs) In order to undertake the assessment, it is necessary to calculate the individual dioxin/furan congener emission rates. For the purposes of this assessment, the congener profile used for the proposed installation is based on the standard profile for municipal waste incinerators ( MWIs ) derived by HMIP. The individual dioxin/congener emission rates are then calculated as indicated in the footnotes to Table 2. Note that the individual congener I-TEFs are detailed in Table 2 for reference The individual dioxin/congener emission rates detailed in Table 2 are then inputted into the IRAP-h View model (note that the model software takes account of the I- TEFs). P2157/R009 20

25 Table 2 Dioxin and Furan Congener Profile and Emission Rates Dioxin/Furan Congener Individual Dioxin/Furan Congener Concentrations in HMIP Representative MWI (ng/nm 3 ) (1) Equivalent Individual Dioxin/Furan Congener Concentrations at IED ELV (ng/nm 3 ) (2) Individual Dioxin/Furan Congener Emission Rates RERC (g/s) (3) 2,3,7,8 - TCDD E ,2,3,7,8,9 - HxCDD E OCDD E ,2,3,4,6,7,8 - HpCDD E OCDF E I-TEF 1,2,3,4,7,8 - HxCDD E ,2,3,7,8 - PeCDD E ,3,7,8 - TCDF E ,2,3,4,7,8,9 - HpCDF E ,3,4,7,8 - PeCDF E ,2,3,7,8 - PeCDF E ,2,3,6,7,8 - HxCDF E ,2,3,6,7,8 - HxCDD E ,3,4,6,7,8 - HxCDF E ,2,3,4,6,7,8 - HpCDF E ,2,3,4,7,8 - HxCDF E ,2,3,7,8,9 - HxCDF E Notes to Table 3 (1) Taken from Table 7.2a, Risk Assessment of Dioxin Releases from Municipal Waste Incineration Processes, HMIP, The concentrations indicated are based on an ELV of 1ng/Nm 3 (expressed as I-TEQ) before correction for the individual congener I-TEFs. (2) The concentrations indicated are based on the IED ELV of 0.1Nng/m 3 (expressed as I- TEQ), again before correction for the individual congener I-TEFs. (3) The emission rates have been calculated from the individual concentrations at the Equivalent IED ELV of 0.1Nng/m 3 (before correction for the individual congener I-TEFs) and the discharge stack volumetric flow rate at reference conditions (i.e. 273K, 101.3kPa, 11% dry oxygen). P2157/R009 21

26 7. STEP 4: RISK ESTIMATION 7.1. Assessment Criteria Risk estimation involves combining the exposure quantities and the toxicity benchmarks to calculate the excess lifetime cancer risks and non-cancer hazard for each of the pathways and receptors Cancer Risk Cancer risk from exposure to emissions is the probability that a human receptor will develop cancer, based on a unique set of exposure, model, and toxicity assumptions. The current UK approach to HHRA utilises a range of acceptable risk levels ranging from to for the different contaminants and pathways of exposure (for example, a risk of is interpreted to mean that an individual has up to a one in 100,000 chance of developing cancer during their lifetime from the evaluated exposure). In the UK, a risk level of is used for all carcinogenic contaminants considered in this assessment Non-cancer Risk - Hazard Quotient Non-cancer health risks can include acute, or short- term health problems such as eye irritation, respiratory irritation, and headaches, and chronic, or long-term problems such as permanent damage to organs, the central nervous system, or reproductive functions, and developmental problems in children. Non-cancer health risk is defined by a Hazard Quotient ( HQ ) The term Hazard Quotient ( HQ ) is used in the IRAP-h View model to describe the risk associated with the potential for developing non-cancer health effects as a result of exposure to COPC. The hazard quotient is not a probability but rather a comparison of a receptor s potential exposure relative to a standard exposure level. The standard exposure level is calculated over a similar exposure period and is estimated to pose no unacceptable risk in terms of adverse health effects to potential receptors Standard risk assessment models assume that, for most chemicals with non-cancer effects, the non-cancer effects exhibit a threshold response. This means, there is a level of exposure below which no adverse effects will be observed Assessment of the potential for health effects associated with a threshold relationship typically involves: comparing an estimate of ingested exposure to a Reference Dose ( RfD ) for oral exposure (i.e. a tolerable daily intake ( TDI ); and comparing an estimated chemical-specific air concentration to the Reference Concentration ( RfC ) for direct inhalation exposures An RfD is a daily oral intake rate that is estimated to pose no unacceptable risk of adverse health effects, even to sensitive populations over a specific exposure duration (normally 70 years). A RfC is an estimated daily concentration of a chemical in air, P2157/R009 22

27 the exposure to which over a specific exposure duration poses no unacceptable risk of adverse health effects, even to sensitive populations The comparisons of oral and inhalation exposure estimates to RfD and RfC values are known as hazard quotients. A hazard quotient of less than or equal to 1 is considered health-protective (USEPA Superfund). For example, an HQ of 2 means the concentration of toxic substances in the air at the point of exposure is predicted to be twice as high as is generally thought to be safe, a HQ of 0.99 or below means the concentration of toxics in the air at the point of exposure is thought to be safe. The levels defined as "safe" are designed to protect the most sensitive individuals in a population Assumptions Throughout this assessment, where there was uncertainty in respect of the input data, a precautionary approach was used to estimate the risks from exposure to COPCs from the RERC. This approach was taken to ensure that the assessment was health protective In accordance with the tiered approach to environmental risk assessment, this study considered worst-case scenarios for all receptors in assuming multiple exposure conditions where all pathways of exposure in each land use scenario were considered to be potentially viable (see Section 5.6) Risk Estimation Results Using the IRAP-h View model, a human health risk assessment for exposure to dioxins and furans has been undertaken. The following calculations were undertaken: estimates of the combined cancer risks and non-cancer (Hazard Quotients) for all identified receptors; estimates of risk and hazards associated with pathways of exposure; evaluation of infant exposure via breast milk to COPCs with appropriate biotransfer factors; and a comparison of the total daily intake of dioxins and furans the the UK s Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment ( COT ) tolerable daily intake ( TDI ) values. (Note: The COT is an independent scientific committee that provides advice to the Food Standards Agency, the Department of Health and other Government Departments and Agencies on matters concerning the toxicity of chemicals). P2157/R009 23

28 Cancer Risk The total cancer risk estimated by the model, based on the air dispersion modelling prediction of air concentrations and depositions by ADMS 5, for the worst case scenarios maximum emissions from the proposed installation were calculated Table 3 details the total cancer risk, for all receptor grouped by receptor type (note: not all scenarios were modelled for each receptor - for example the farmer scenario was not modelled for receptors such as the schools - these are noted as n/a' in the Tables 3-7). Table 3 Ref R1 Cancer Risk for All Receptors Location Stoneyhill Primary School Resident Resident Child Total Cancer Risk Farmer Farmer Child Fisher Fisher Child 6.71E E-08 n/a n/a n/a n/a R2 Whitehill 5.79E E E E E E-06 R3 Queen Margret University Halls 2.86E-08 n/a n/a n/a n/a n/a R4 Stoneybank 7.91E E E E E E-06 R5 R5 Queen Margret University Whitecraig Primary School 1.39E-11 n/a n/a n/a n/a n/a 5.12E E-10 n/a n/a n/a n/a R7 Old Craighall Village 8.54E E E E E E-06 R8 Wellington Farm 1.47E E E E E E-06 R9 Newton House 1.02E E E E E E-06 R10 Dalkeith High School 5.56E E-10 n/a n/a n/a n/a R11 Old Craighall Road 1.23E E E E E E-06 R12 R13 R14 R15 Shawfair Area (existing) Shawfair Area (existing) Shawfair Area (existing) Shawfair Area (existing) 1.16E E E E E E E E E E E E E E E E E E E E E E E E-06 R16 Lowe's Fruit Farm 7.12E E E E E E-06 R17 Newton Village 1.21E E E E E E-06 R18 Spire Shawfair Hospital 9.43E E-08 n/a n/a n/a n/a R19 Newton Village 2.25E E E E E E-06 R20 Millerhill Road - west 4.33E E E E E E-06 R21 Danderhall 2.62E E E E E E-06 P2157/R009 24