Remedial Targets Worksheet v3.1: User Manual
Contents
1. 3 78E 01 years Figure 6 1 Worksheet for simple hydrogeological calculations er Porosity Calculator _ Simple Remedial Targets Worksheet v3 1 User Manual calcs Levelt Cale Level2 Calc_ _Levels 1 Soil 33 References DETR Environment Agency and Institute for Environment and Health 2000 Guidelines for environmental risk assessment and management Defra and Environment Agency 2004 Contaminated Land Research Report CLR11 Model procedures for the management of land contamination Environment Agency 1999a Methodology for the derivation of remedial targets for soil and groundwater to protect water resources R amp D Publication 20 Environment Agency 1999b ConSim Contamination impact on groundwater Simulation by Monte Carlo method Prepared by Golder Associates UK Ltd Environment Agency 2000 Guidance on the assessment and monitoring of natural attenuation of contaminants in groundwater R amp D Publication 95 Environment Agency 2001a Guide to good practice for the development of conceptual models and the selection and application of mathematical models of contaminant transport processes in the subsurface National Groundwater and Contaminated Land Centre report NC 99 38 2 Solihull Environment Agency 2001b Benchmarking and guidance on the comparison of selected groundwater risk assessment models National Groundwater and Contaminated Land Centre report NC 00 14 Solihull En2. Air filled soil porosity 0 Dry bulk density of soil Psoil Henry s Law Coefficient for non volatile contaminants this should be zero poy It is important to remember that data entered on the Level 1 worksheet relate to materials in the source zone that is to say the porosity density fraction of organic carbon etc values relate to the materials in which contaminants are located This will normally be soil made ground or unsaturated rock If a value for Kg is derived from literature sources it is important to ensure that it is relevant to the matrix in which contaminants are located at the site being considered The following list identifies important issues related to each parameter required Water filled soil porosity 9w fraction of the pore space within the source zone material that is filled with water Expressed as a fraction between 0 and the total porosity value The water filled porosity value can be derived from water or moisture Remedial Targets Worksheet v3 1 User Manual 15 content measurement and density measurements To determine the appropriate water filled porosity complete the Porosity Calculator worksheet which is described in Section 4 7 This value should then be entered into the appropriate blue cell in the Level 1 worksheet Air filled soil porosity 9a fraction of the pore space within the source zone material that is filled with air Expressed as a fraction between 0 and total poros
3. z the off set distance of the compliance point or monitoring borehole from the groundwater plume centreline of flow Figure 4 5 Pollution Groundwater flow direction Lateral off set z source centre line of plume of receptor from flow line SUNO m P3 Non pumping well off set from plume centre line Figure 4 5 Lateral off set z of compliance point from plume centre line Remedial Targets Worksheet v3 1 User Manual 25 Distance vertical to the compliance point y the vertical off set distance of the compliance point or monitoring borehole from the groundwater plume centreline of flow Figure 4 6 Non pumping Source area monitoring borehole Plume centre line Vertical off set y of screen from plume centre Well screen positioned away from plume centre line Figure 4 6 Vertical off set y of receptor well screen from plume centre line The vertical and lateral distance to the compliance point should be set as zero in order to determine remedial target concentrations Distances should only be entered where it is necessary to predict the concentration of a contaminant in a borehole that is offset from the plume centre line or to derive a trigger concentration for a compliance monitoring borehole gt 26 Time t For time variant assessments the worksheet can be used to predict the contamin
4. all Contaminant Pollutant from Level at 8 Target Concentration Cr 01 mgil from Levelt coeffici e nt 3 Dilution Factor DF 1 70E 01 from Level 2 10 m Select analytical solution click on brown cell below then on pull down menu 1806 01 Ogata Banks Equations in R amp D Pub 20 Select nature of decay rate click on brown cell below then on pull down h for simulating degradation of pollutants Apply degra menu rate to pollutants in all phases 3 00E 02 231 03 7 00E 01 100E 01 1656 00 150E 01 106E 02 8 00E 00 from Level 2 adjusted 180 01 Paidown lis Dispersivities 10 1 0 1 of pathway le from Level 2 1L00E 02 0 00E 00 0 00E 00 100E 100 180E 01 10 000 1000 0 100 Ver Parameter values should he checked against Levei Calculated Parameters Variable 567E 01 2 98E 00 2316 03 Hydraulic gradient i 106E 02 Rate of ox 190E 01 a 3226 01 Remedial Targets 3 11E 00 fraction js time variant OPENS colt Level 3 Remedial Target Ogata Banks mgA or 109 01 __ mgkg Fo Distance to compliance point 100 see options see options see options see options Calculated Level 3 Remedial Target m as ikg Select option for applying degradation rate Select option for specifying initial concentration Select option for dispersivit
5. E Cc Remedial Targets Worksheet Release 3 1 Calculation of contaminant concentration in groundwater from a soil source hiy input required is Soil Contaminant Concentration 01 mgkg tenuation factor corcep ar amea Predicted concentrations at compliance point Level 1 c mee Level 2 2 86E 01 Level 3 c ares Predicted concentrations between source and compliance point Level 3 Distance m Concentration mail 0 00 2 86E 01 5 00 2 39E 02 10 00 2 00E 03 15 00 167E 04 20 00 139E 05 25 00 116E 06 30 00 9736 08 35 00 8 13E 09 40 00 679E 10 45 00 567E 50 00 473 12 55 00 3 95E 13 60 00 330E 2 75E 15 229E 16 191E 17 159E 18 132 19 110E 20 9 12E 22 7 57E 23 I4 41 gt PII Level4 Soil Soil Impact Results Level3 Groundwater Porosity Calculator Simple calcs_ _Leveli Calc_ Level2 Calc _Level3 1 Soil Cal Figure 4 8 Soil impact calculation worksheet 4 7 Porosity calculator worksheet The air and water filled porosities can be difficult parameters to measure directly at a site area but can be estimated from soil bulk density wet or dry particle density and moisture content The calculations presented in the Porosity Calculator worksheet are suitable for inclusion within the Level 1 and 2 soil worksheets and for the Level 2 Vapour assessment If using dry bulk density data the formulae used within the model are as follows Part
6. Remedial Targets Worksheet v3 1 User Manual gt Effective porosity n of the aquifer drainable pore space In fissured and dual porosity aquifers the effective porosity may be assumed to be the fissure porosity This value applies to the saturated zone only and is not therefore the sum of the air and water filled porosities used in Level 1 The Porosity Calculator worksheet should not be used to derive values of effective porosity gt Hydraulic gradient i gradient of the water table in the saturated aquifer The hydraulic gradient is entered in the level 2 worksheet but is then corrected to ensure that groundwater fluxes up and down gradient of the site balance The correction is f DF level3 Level DF 1 gt where DF is the Dilution Factor calculated at Level 2 using relative volumes of infiltration and groundwater flow The corrected value for the hydraulic gradient is shown in a coloured light green box This value cannot be changed in the level 3 worksheet and the hydraulic gradient can only be changed in the level 2 worksheet gt Hydraulic conductivity K of the aquifer in a water saturated state The hydraulic conductivity is entered in the level 2 worksheet and automatically transferred to the level 3 worksheet gt Distance to compliance point x the distance from the source to the point at which compliance with an environmental standard is required gt Distance lateral to the compliance point
7. The worksheet calculates error functions and complimentary error functions Before using the worksheet it may be necessary to add these capabilities by clicking the following from the pull down Tools menu Tools gt Add Ins Analysis ToolPak and Analysis ToolPak VBA When the worksheet is first opened the initial screen will prompt the user to save the simulation in a discrete file location Remedial Targets Worksheet v3 1 User Manual 7 3 Overview The Remedial Targets Worksheet calculates solutions to equations presented in the Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination Environment Agency 2006a It should only be used in conjunction with that document Version 3 1 of the Remedial Targets Worksheet incorporates a number of changes from Version 2 which are summarised below e Air and water filled porosities can be calculated from moisture content and density data e The calculation of the partition coefficients for polar organic compounds has been corrected to include fraction of organic carbon e Dilution by groundwater flow only is considered Dilution in the receptor should be dealt with as described in Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination The scientific basis of these updates is described in detail in the Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination Environment Agency 2006a The remedial t
8. data entry cells will be blacked out Data sources should be documented on the worksheet in the yellow cells The following list provides additional information on data required to derive Level 2 remedial targets gt Infiltration Inf amount of recharge passing through contaminated source zone May be a combination of percolating precipitation leakage from sewers and drains and deliberate discharges to soakaway Note that the required units are m day so rainfall data in mm year will need to be converted to the required units gt Area of contaminant source A The plan area of the soil contamination should be entered This area is not used in the calculation and is for information only gt Length of contaminant source L The length of the source parallel to the groundwater flow direction should be entered gt Saturated aquifer thickness da distance from the water table to the base of the saturated aquifer gt Hydraulic conductivity K of the saturated aquifer used to calculate groundwater flow in the underlying aquifer gt Hydraulic gradient i gradient of the water table in the saturated aquifer 18 Remedial Targets Worksheet v3 1 User Manual Width of site w longest extent of the site perpendicular at 90 degrees to groundwater flow direction This value is carried through to the level 3 assessment and is set as the width of the contaminant source Sy Mixing zone depth Mz thickness of sat
9. recycled stock which is 100 post consumer waste and is totally chlorine free Water used is treated and in most cases returned to source in better condition than removed Further copies of this report can be downloaded from the Environment Agency s website www environment agency gov uk publications 2 Remedial Targets Worksheet v3 1 User Manual Author s J W N Smith Environment Agency Science Group M A Carey Entec UK Ltd Dissemination Status Publicly available Keywords Contaminated soil groundwater remediation standard User guide software user guide Research Contractor Entec UK Ltd Canon Court Abbey lane Abbey Foregate Shrewsbury SY2 5DE Environment Agency s Project Manager Jonathan Smith Science Group Science at the Environment Agency Science underpins the work of the Environment Agency by providing an up to date understanding of the world about us and helping us to develop monitoring tools and techniques to manage our environment as efficiently as possible The work of the Science Group is a key ingredient in the partnership between research policy and operations that enables the Agency to protect and restore our environment The Environment Agency s Science Group focuses on five main areas of activity Setting the agenda To identify the strategic science needs of the Agency to inform its advisory and regulatory roles Sponsoring science To fund people and projects in response t
10. to degradation such as heavy metals non radioisotopes and chloride or there is no evidence of degradation from field data a half life of 9 9E 99 years should be used A degradation rate of zero equates to a substance that degrades instantaneously Width of source Sz The width of the pollutant plume in the aquifer at the source i e below the contaminated site normal at 90 degrees to groundwater flow should be entered This value is carried forward from the Level 2 worksheet and can only be changed in the Level 2 worksheet Plume thickness at source Sy The thickness of the pollutant plume in the aquifer at its source i e below the contaminated site The depth of the source is assumed to be equal to the mixing zone thickness M used in Level 2 and this value is automatically carried forwards from the latter worksheet Care should also be taken to ensure that the modelled effects of vertical dispersion are not so great as to simulate a plume that extends beyond the physical limits of the aquifer If the worksheet calculates that the modelled effects of vertical dispersion are to spread the plume beyond the thickness of the aquifer unit a warning will be posted that Dispersed plume thickness exceeds aquifer thickness Reduce vertical dispersivity In this the value for vertical dispersivity should be reduced This can only be achieved under option to enter dispersivity values Dry Bulk density of the aquifer material
11. 1996 Environment 2006 LO Agency enhancing improving cleaning restoring hanging tackling protecting reducing reating a better place influencing inspiring advising managing adapting Remedial Targets Worksheet v3 1 User Manual Hydrogeological Risk Assessment for Land Contamination ea br e std vr1othanni The Environment Agency is the leading public body protecting and improving the environment in England and Wales It s our job to make sure that air land and water are looked after by everyone in today s society so that tomorrow s generations inherit a cleaner healthier world Our work includes tackling flooding and pollution incidents reducing industry s impacts on the environment cleaning up rivers coastal waters and contaminated land and improving wildlife habitats This report is the result of research commissioned and funded by the Environment Agency s Science Programme Published by Environment Agency Rio House Waterside Drive Aztec West Almondsbury Bristol BS32 4UD Tel 01454 624400 Fax 01454 624409 www environment agency gov uk Environment Agency October 2006 Product Code SCH01006BLMX E E All rights reserved This document may be reproduced with prior permission of the Environment Agency The views expressed in this document are not necessarily those of the Environment Agency This report is printed on Cyclus Print a 100
12. 21 Ogata Banks equation vertical dispersion in two directions oleae oo a fe Nae a S S Gane gee joe re erf 2 erf 2 erf 2 erf 2 Steady state Domenico equation vertical dispersion in one direction 4A S Cup C exp gt 1 hs erf erf oF 2a u 2 a Xx 4 Jax Steady state Domenico equation vertical dispersion in two directions cali EE a u a x ax Time variant Domenico equation vertical dispersion in one direction AG x Aa 1 Aa Sy S CEp 5 vol q p gt Nae T ut p P Near ler Time variant Domenico equation vertical dispersion in two directions Co x _ 42a 1 _ 42a Sy S Crp z ool q hs i Jla a ut i gt Jl ler Important points to note in selecting which approach to adopt include e The Environment Agency s preferred analytical solution for calculating Level 3 remedial targets for pollutants subject to first order biodegradation in a homogeneous aquifer is the Ogata Banks solution 22 Remedial Targets Worksheet v3 1 User Manual Where an aquifer is strongly heterogeneous consideration should be given to the appropriateness of any of the solutions If a time variant solution is used the time should be set to 9 9F 99 when deriving remedial targets The three analytical solutions employed all assume as a default that the source of pollution is located at the top of the aquifer and vertical dispersion i
13. L 2 305 87 RUSE 01 2 41862 BADE 2 005 62 BOSE 1 956002 608 01 1 8SE 02 7206 01 arsa Bae 1 666002 ASEM 157E 8 10E 01 1 48602 4 406 02 1 336 02 1 25602 1 10602 1 42602 10ste 9 99001 CETE oaz ssot e Tet Note if contaminant is not sudaect to frat order degradation then set hal Whe at 9 969 44 pi Introdxtion Z Levelt Sol Z Levez Sol Levels sou Levelt sod Sol bnpact Repits Level Groundwater Poroety Calculator J Semple cals J Level Cok J Levelt Cok Z level sac e nw G m 3 4 e Figure 4 7 Comparison of contaminant behaviour predicted by analytical solutions 4 6 Soil impact calculations worksheet The soil impact calculation worksheet Figure 4 8 presents the predicted impact on water quality as a contaminant concentration arising from a soil source that are calculated at each of the three levels The spreadsheet allows the soil contaminant concentration as mg kg to be entered and uses this to calculate e Pore water concentration e Contaminant concentration in groundwater below the source due to dilution e Contaminant concentration at the compliance point The data needed for these calculations are automatically transferred from the Level 1 to 3 soil worksheets The worksheet also includes a figure and table that gives calculated concentrations in groundwater between the source and the compliance point 28 Remedial Targets Worksheet v3 1 User Manual D ESE A I
14. aking into account dilution and remedial target For the third option the spreadsheet will calculate contaminant concentrations as a ratio C Co 4 Approach to contaminant partitioning between the aquifer matrix and groundwater e User defined partition co efficient e Calculate Kd on basis of non polar organic species e Calculate Kd for polar organic species 5 Approach to modelling dispersivity within the aquifer e User defined dispersivity values e Calculated dispersivity based on length of flowpath e Calculated dispersivity following empirical relationship derived by Xu amp Eckstein 1995 The options included within the worksheet solve the analytical solutions given below please refer to Remedial Target Methodology for keys to parameters It should be noted that the default solutions used to calculate remedial targets in Level 3 Soil assume vertical dispersion in only one direction This is consistent with the conceptual model of a soil source leaching down to the water table and then dispersing within the aquifer However solutions using two directional vertical dispersion are presented in the calculation sheets should this be more representative of the situation on a site Ogata Banks equation vertical dispersion in one direction c Seat eji a sol fie fe alm pare z Se EE T 5 Sy erf 2 erf 2 7 2 erf i 2ya 2 a X 2 2a zi Remedial Targets Worksheet v3 1 User Manual
15. ant fate at various times e g to predict when a plume might reach a receptor or to predict the size of a plume after 10 years When the worksheet is used to derive remedial targets the time in time variant options should be set to a very large number such as 9 9E 99 in order to avoid overestimating the required remedial targets to protect receptors Soil water partition coefficient Ky values should relate to the partitioning of contaminants between groundwater and aquifer materials For conservative contaminants K4 equals zero Fraction of organic carbon foc value for the aquifer within which the plume is migrating The foc value used should relate to the unpolluted aquifer material and should not include organic pollutants that may be present in the aquifer Organic carbon partition coefficient Koc Contaminant specific value Koc which describes the partitioning of a substance between organic matter and water An appropriate value must be inserted into the blue cell if calculating Kg for non polar ionic compounds A conservative organic compound has a Koc value of zero Remedial Targets Worksheet v3 1 User Manual gt pH and acid dissociation constants contaminant specific data necessary to derive partition coefficients for polar organic substances Results When each of the blue cells has been completed click on another cell and the worksheet will calculate Level 3 remedial targets for soil and present the resul
16. argets methodology has been developed to help assessors derive site specific remedial targets for contaminated soils and groundwater that are protective of the wider water environment The framework does not consider the risks posed by contaminants to other receptors such as humans for soil sources buildings flora and fauna However the risks to these and any other relevant receptors need to be considered when developing remedial objectives for a site as a whole Readers who are unfamiliar with the concepts of environmental risk assessment and the Agency s approach to protection of groundwater are directed to the following documents e DETR etal 2000 Guidelines for environmental risk assessment and management The Stationery Office e Defra and Environment Agency 2004 Contaminated Land Research Report CLR11 Model procedures for the management of land contamination e Environment Agency 2006a Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination e Environment Agency 2006b Groundwater Protection Policy and Practice 1 3 consultation version The remedial target methodology and the worksheet have been developed to help assessors derive site specific remedial targets for sites where soil and or groundwater are already contaminated as a consequence of past activities and practices The worksheet should only be used in this context in particular due to the requirements of the EU Groundwater Directiv
17. bust conceptual model has been developed and the assessor is satisfied that the calculations performed by the worksheet are relevant to the processes described within that conceptual model Data quality is also a particular concern Data used should be relevant reliable and derived from tests at the site or be relevant to the site The provenance and relevance of all data included in an assessment using the worksheet should be documented by the assessor and included in the report s submitted to the Agency for consideration The Agency has produced guidance for its staff on reviewing submitted assessments and this may be of use to assessors preparing reports for submission to the Agency e Environment Agency 2001d Guidance on the assessment and interrogation of subsurface analytical contaminant fate and transport models National Groundwater and Contaminated Land Centre report NC 99 38 1 Solihull The structure of the assessment framework is described in detail in the Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination and is not reproduced here It is important to remember however that as assessors progress through the levels the point at which compliance is tested will change Figure 3 1 and the amount of data which must be collected from the site will increase This worksheet should only be used to derive remedial targets at a level for which adequate site specific data have been obtained Note the term
18. c value as a fraction between 0 and 1 for the soil made ground or other material in which the contaminant source is located For example if there is 0 5 organic matter in an aquifer material foc would be 0 005 Organic carbon partition coefficient Koc Contaminant specific value Koc which describes the partitioning of a substance between organic matter and water An appropriate value must be inserted into the blue cell if calculating Kg for non polar ionic compounds A conservative organic compound has a Koc value of zero Sorption coefficient for neutral species Koc n onto soil made ground matrix in which a contaminant source with polar properties is located Sorption coefficient for ionised species Koc onto soil made ground matrix in which contaminant source with polar properties is located Positively charged ions generally have a greater potential to sorb to the soil matrix because most subsurface solids have a negative net surface charge 16 Remedial Targets Worksheet v3 1 User Manual OH value of the pore water Measure of the concentration of hydrogen ions H Specifically the negative logarithm of the hydrogen ion concentration Acid dissociation constant pKa of an ionised substance in the pore water Once data have been entered in all of the blue cells click away on another cell and the Level 1 remedial target will presented as mg kg in the grey box at the bottom of the screen Yellow
19. ce of parameter value cells with appropriate text will not prevent calculation of the remedial targets it is good practice to complete this task The Environment Agency will expect submitted reports to include these details Grey cells contain the results of each simulation and green cells contain information derived from another part of the spreadsheet which although not essential for the simulation is useful to the assessor If the assessor moves the cursor over the red triangles at the corner of certain cells further information is revealed on the data required or equations solved 4 2 Introduction worksheet When starting a new assessment users MUST complete details on the Introduction worksheet first Figure 4 1 This worksheet is displayed for all assessment options Data required in blue boxes on the Introduction worksheet include Name and address of the site being assessed Name of assessor date that assessment was completed and run version number Name of contaminant Target concentration Basis for target concentrations e g EQS DWS limit of detection All blue cells on the Introduction sheet must be completed before moving onto any other worksheets Data entered for the pollutant name target concentration site name assessor s name date of assessment and identifying run number are automatically transferred to each of the subsequent data entry sheets These details can not be amended within the s
20. cells the origin or source of all data used should be documented Yellow cells are provided on the worksheet for brief notes of data provenance 4 4 Level 2 Soil worksheet The Level 2 Soil worksheet Figure 4 3 takes data already entered at Level 1 and calculates a Level 2 remedial target that includes a factor for dilution of the contaminants Al B nace D E F le H 1 1 Remedial Targets Worksheet Release 3 1 Pol l utant name and targ et Level 2 Soil oncentration automatically Contaminant Pollutant from Level 1 This sheet calculates the Level 2 remedial target fi ra n sfe rre d fro m Target concentration Cr 0 1 mg __ trom Level 1 water mgA k i Introduction sheet The measured soil concentration as mg kg or pore water concentration should be cI remedial target to determine the need for further action Equations presented in R amp C Input Parameters Variable Value Unit Source of parameter value Standard entry Intittration Inf 5 00E 04 mid Area of contaminant source A 170E 04 m Not used in calculation Entry for groundwater flow below site Length of contaminant source in direction of groundwater flow L 1 00E 02 m S e ect th e p refe rred Saturated aquifer thickness da 1 50E 01 m soe Hydraulic Conductivity of aquifer in which dilution occurs K 8 00E 00 mid m eth od to set th e mixin g adient of water tabl
21. e i 41 00E 02 _ fraction h k f h Width of contaminant source perpe groundwater flow wW 2 00E 02 m mT Background concentration of contaminant in gr eath site Cu 00000 mi t zone t ICKNESS trom t e Define mixing zone depth by specifying or calculating depth u wn list Specify p u l l dow n menu Enter mi ickness Mz 1 00E 01 Calculated mixing zone thickness Mz Calculated Parameters soa If the entered mixing Dilution Factor DF 1 70E 01 s Level 2 Remedial Target 1 70E 00 mgl For comparison with measured pore water concentration This assumes Lev Rem o n e l S th icke r th a n o or i 2 50600 mgka ror comparison with measured soi concentration Th he saturated aquifer gumes Level 1 Remedial Target calculated from soil water la warning is posted Additional option Calculation of impact on receptor Concentration of contaminant in contaminated discharge entering receptor Cc 5 00E 00 mga Calculated concentration within receptor dilution only 2 94E 01 mal 0 Calculated level 2 remedial targets are presented here as mg kg for comparison with soil analyses and mg l for comparison with leachate analysis wlan Ta Fon et N t anlo Cait Siaa eai Minced Shands a raai aan aaa e an Aa aA Ff aa eee al zal e Figure 4 3 Level 2 Soil worksheet The level 2 worksheet allows dilution by groundwater flow below the site to be taken into account in determining the remedial target for contaminated soil Note attenuation in the unsaturat
22. e and Dangerous Substances Directive it may be inappropriate to use parts of this framework to assess the acceptability of discharges from new or current activities Before selecting this or indeed any other assessment model or tool assessors should have developed a conceptual model of the site They should be satisfied that the tool they select to model the site is appropriate both in respect of representing the 8 Remedial Targets Worksheet v3 1 User Manual conceptual model and in performing analyses to a level that is appropriate to the quality of the input data Guidance on these issues is provided in e Environment Agency 2001a Guide to good practice for the development of conceptual models and the selection and application of mathematical models of contaminant transport processes in the subsurface National Groundwater and Contaminated Land Centre report NC 99 38 2 Solihull e Environment Agency 2001b Benchmarking and guidance on the comparison of selected groundwater risk assessment models National Groundwater and Contaminated Land Centre report NC 00 14 Solihull The development of a robust conceptual model is perhaps the most important aspect in the process of successfully estimating and evaluating environmental risks The use of any mathematical modelling tool without first developing a robust conceptual model is likely to result in meaningless output and poor decision making This worksheet should only be employed where a ro
23. ed zone is not considered in this spreadsheet and should be derived separately The equations solved for a dilution factor DF at Level 2 are as follows for explanation of terms in equations see Remedial Target Methodology Remedial Targets Worksheet v3 1 User Manual 17 K iM L nf C KiM C DF oy e L Inf C The assessor will also need to select how to determine the thickness of the mixing zone within the aquifer Two options are given 1 The thickness of the mixing zone can be calculated using the following solution after USEPA 1996 or 2 The thickness of the mixing zone can be specified by the assessor The empirical calculation for mixing zone thickness is the following relationship M 0 01122 tadji exf ZERE i da The thickness of the mixing zone cannot exceed the saturated thickness of the aquifer If a value greater than the saturated aquifer thickness is entered the worksheet posts a warning that mixing zone exceeds saturated thickness Generally the full thickness of the aquifer will not be available for mixing of contaminants and a lesser thickness may be derived from evidence of high permeability zones from borehole logs annual water table fluctuation from hydrographs or local experience Many UK aquifers are layered systems with significant vertical heterogeneity that limits the potential for vertical mixing The data entry cells that need to be completed will be highlighted blue All other
24. evel 3 Soil Data entry for calculating Level 3 remedial targets for soil and presentation of results Soil impact results Tabulates predictions of impact on water quality from contaminated soil at each Level Simple calculations Data entry and computation of simple hydrogeological calculations Porosity Calculator Data entry and calculation of air and water filled porosities Level 1 Calc Calculation of Level 1 remedial targets for soil from data input to Level 1 Soil Level 2 Calc Calculation of Level 2 remedial targets for soil from data input to Level 2 Soil Level 3 1 Soil Calc Calculation of Level 3 remedial targets for soil using the Ogata Banks solution from data input to Level 3 Soil Level 3 2 Soil Calc Calculation of Level 3 remedial targets for soil using the steady state Domenico solution from data input to Level 3 Soil Level 3 3 Soil Calc Calculation of Level 3 remedial targets for soil using the time variant Domenico solution from data input to Level 3 Soil Level 3 Groundwater Data entry for calculating Level 3 remedial targets for groundwater and presentation of results Level 3 1 G Calc 2 Calculation of Level 3 remedial targets for groundwater using the Ogata Banks solution from data input to Level 3 Soil Level 3 2 G Calc 2 Calculation of Level 3 remedial targets for groundwater using the steady state Domenico solution f
25. ferent from data input at Level 1 where the fate of contaminants in the soil zone was modelled The following list identifies important issues related to each datum required gt 24 Half life for degradation t12 Contaminant decay is modelled as a first order reaction and degradation is defined by a half life expressed in days The worksheet gives the option to model biodegradation of dissolved phase only where data are from laboratory analysis of degradation in water or for the whole system where data are from field observations or column tests and are corrected to remove the effects of dispersion and retardation If radioactive decay occurs it may be assumed that this decay occurs irrespective of the phase in which the contaminant is located i e in both the sorbed and dissolved phases Decay rates should be based on field observation of contaminant destruction in groundwater or on conservative literature values where their application is supported by field data Any literature values used must relate to the behaviour of the chemical under similar environmental conditions e g redox pH contaminant concentrations presence of other substances etc Guidance on assessing contaminant attenuation is given in Environment Agency R amp D Publication 95 Guidance on the assessment and monitoring of natural attenuation of contaminants in groundwater Environment Agency 2000 Where contaminants are being assessed that are not subject
26. gle contaminant at a time using a deterministic method that is to say a remedial target is calculated on the basis of a single parameter value for each variable It is recommended that analysis of the sensitivity of the calculated remedial target to changes or variability in the input data is undertaken as part of the risk assessment process Understanding how the magnitude of risks vary with changes in input parameter values in essential to understanding the certainty that can be placed on any prediction Two principal methods are available to take account of parameter uncertainty A common method that allows parameter variability to be considered is the use of probabilistic methods such as Monte Carlo analysis This worksheet is password protected and this may prevent the use of common commercial tools such as Crystal Ball and Risk to undertake Monte Carlo analysis If Monte Carlo analysis is required it is recommended that an alternative assessment tool such as ConSim Environment Agency 1999b is used A second approach to assessing the effects of parameter variability on the calculated remedial targets is described in chapter 8 of the Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination By varying selected input parameters in turn and observing the effect on the calculated remedial target it is possible to determine which parameters make the greatest effect on the results Having assessed which parame
27. i Vid Rake article _ density _ l Dry _bulk _ density Moisture _ content Particle _ density Initial _ Saturation Void _ ratio Dry _ bulk _ density Particle _ density Total _ porosity 1 1 00 initial _ saturation total _ porosity Air _ filled _ porosity 100 Water _ filled _ porosity total _ porosity air _ filled _ porosity Remedial Targets Worksheet v3 1 User Manual 29 where porosities and void ratio are expressed as fractions densities are expressed as g cm moisture content expressed as by weight initial saturation expressed as If using wet bulk density data the wet bulk density is converted to a dry bulk density using the following formula then the air and water filled porosities are calculated using the formula above 100 wet _ bulk _ density 100 Moisture _ content Dry _ bulk _ density It is important to note that these equations cannot be used to calculate the effective porosities used for the Level 3 Soil and Groundwater assessment worksheets 4 8 Level 3 Groundwater worksheet The Level 3 Groundwater worksheet Figure 4 9 performs the same groundwater transport calculations as Level 3 Soil with the distinction that it does not require data from Levels 1 and 2 soil worksheets and simply models migration of contaminants within the aquifer Level 3 Groundwater worksheet does however offer the option to simulate contaminant transport with vert
28. ical dispersion in either one or two directions depending whether the plume is located at the edge top or bottom or centre of the aquifer Data requirements for Level 3 Groundwater are similar to Level 3 Soil and are not described further The exception is that the following values need to be entered e Contaminant concentration in groundwater Hydraulic conductivity Hydraulic gradient Source width and depth The calculated remedial targets are restricted to a Level 3 remedial target for groundwater expressed as mg l which should be compared to groundwater quality at the contaminated site The spreadsheet also includes e Graph showing the variation in contaminant concentrations downgradient of the source expressed as mg l 30 Remedial Targets Worksheet v3 1 User Manual e Table giving calculated concentrations in groundwater between the source and the compliance point expressed as mg l R amp D Publication 20 Remedial desi Worksheet Release 3 1 Level 3 Groundwater hee Note keput Parameters wring pull down menu Variable Valor Usi Soarew Connes Cr Irom Levert Tegel Conceatton Cy Kemet mat hom Leott 2ittso323 A E kdi Longitudinal disper shetty Hransverse dispersing Veetieal Bapes unity 333 Wrench content abn M Balance 8 BANT os poa Ca 2I my Altenuation Hector owe way vertbeal Sspersion COCED 2048 09 Remedial Targets fi Femeia Taraet DHEM mai lF o conpinsen vor meanset pondran conceem
29. ity value Air filled plus water filled porosities equal the total porosity of the matrix material The air filled porosity value can be derived from water or moisture content measurement and density measurements To determine the appropriate air filled porosity complete the Porosity Calculator worksheet which is described in Section 4 7 This value should then be entered into the appropriate blue cell in the Level 1 worksheet Dry Bulk density Psoi of the soil made ground material in which the contaminant source is located Henry s Law Constant Contaminant specific value that describes the partitioning of a compound between an aqueous solution and the gaseous phase Henry s Law Constant should be expressed in the dimensionless form which can be calculated by multiplying Henry s Law Constant expressed in atm m mol by 42 9 unit conversion at 11 C For inorganic chemicals and non volatile compounds it should be set to zero Soil water partition coefficient Kg Contaminant specific value Kg that describes the partitioning of a substance between the soil made ground matrix and surrounding water Soil water partition coefficients will typically be derived from laboratory column experiments or field data where comparison with a conservative tracer is possible If a contaminant is conservative i e it does not sorb to soil or aquifer materials such as chloride its Kg value is zero Fraction of organic carbon fo
30. level now replaces tier which was used in the original remedial target methodology Agency 1999 Remedial Targets Worksheet v3 1 User Manual 9 Upgradient borehole Contaminant Monitoring Compliance Abstraction borehole or source borehole monitoring other discharge point borehole Groundwater flow Key o Point of compliance for soils at levels 1 2 and 3 Point of compliance for contaminated groundwater at levels 2 and 3 Figure 3 1 Assessment levels and compliance points This spreadsheet does not include for attenuation in the unsaturated zone or for dilution in a specific receptor such as a receiving watercourse or abstraction borehole If these elements need to be included in the assessment then this will need to be undertaken using a separate numerical model 10 Remedial Targets Worksheet v3 1 User Manual 4 Using the worksheet 4 1 General The Remedial Targets Worksheet v3 1 incorporates 16 sheets which have the following functions Table 4 1 Function of worksheets Title of worksheet Function of sheet Introduction Brief instructions entry of site details assessor details enter contaminant and water target concentration for transfer to subsequent sheets Level 1 Soil Data entry for calculating Level 1 remedial targets for soil and presentation of results Level 2 Soil Data entry for calculating Level 2 remedial targets for soil and presentation of results L
31. men Opra Bads Distance to compliance point a m Concentration of contaminat st compliance point CuolG 220 00 mgn Opusiir s alter Loro dogs i z E z g 5 cy g 9 a r a a n a 5 a a D y a 2 a 5 a n 2 9 n C3 a 2 cy cy cy e cy ial oa intel 357 nit al Zee Sada gc eas uve Greats 1 Pei Ctr snc cs inet Cake ewe Cok Line E al O vf Figure 4 9 Level 3 Groundwater worksheet Results When each of the blue cells has been completed click on another cell and the worksheet will calculate Level 3 remedial targets for groundwater and present the results in the grey box at the bottom of the screen Remedial targets are presented as groundwater concentration mg l The spreadsheet also gives the calculated e Groundwater velocity e Contaminant concentration at compliance point e Attenuation factor In addition the spreadsheet includes e Graph showing variation in contaminant concentrations down gradient of the source expressed as mg l for both steady state and time variant solutions e Table giving calculated concentrations in groundwater between the source and the compliance point expressed as mg l for both steady state and time variant solutions Remedial Targets Worksheet v3 1 User Manual 31 5 Sensitivity analysis Each of the worksheets presented allows remedial targets to be calculated for a sin
32. o the needs identified by the agenda setting Managing science To ensure that each project we fund is fit for purpose and that it is executed according to international scientific standards Carrying out science To undertake the research itself by those best placed to do it either by in house Agency scientists or by contracting it out to universities research institutes or consultancies Providing advice To ensure that the knowledge tools and techniques generated by the science programme are taken up by relevant decision makers policy makers and operational staff Steve Killeen Head of Science Remedial Targets Worksheet v3 1 User Manual Executive Summary This document has been prepared to support risk assessors using the Remedial Targets Worksheet v3 1 which was developed to accompany the document Remedial Targets Methodology Hydrogeological risk assessment for land contamination The methodology and the MS Excel97 worksheet for which this user manual has been prepared provide a framework for assessing the risks to controlled waters from land contamination and for deriving remedial targets where those risks are unacceptable The remedial targets produced by this method should be combined with provisional remedial objectives for all other relevant receptors present at a site such as humans flora fauna and building materials in order to address all of the risks that may be present on a site as a whole The workshee
33. oil and groundwater to protect water resources Agency 1999a This document describes the functionality of the worksheet and gives guidance on its use It is not intended to describe the technical basis underpinning environmental risk assessment the regulatory and policy context within which risk assessments are undertaken or the Environment Agency s approach to assessing risk assessment reports The worksheet should only be used by suitably experienced risk assessors who have previously read the Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination and who are conversant with the relevant UK legislation policy and guidance 6 Remedial Targets Worksheet v3 1 User Manual 2 Obtaining and installing the worksheet The Remedial Targets Worksheet v3 1 can be downloaded from the Environment Agency s website www environment agency gov uk publications free of charge The worksheet has been prepared and tested in Microsoft Excel97 on the MS 95 2000 XP operating systems The file comprises about 810KB and should not require any significant additional computing capability beyond that needed to run Microsoft Excel97 It is recommended that a blank copy of the worksheet as downloaded from the Agency s website is saved to a safe file and that each simulation is saved as a distinct file In order to enable the worksheet a number of capabilities are required in Excel that may not automatically be set
34. ontam K x i n x Ri Time for contaminant to reach receptor teontam N x Ry x distance K x i Retardation factor Ri Ry 1 Ka x p n The results of each calculation are presented in a range of units for ease of interpretation 2 Simple hydrogeological calculations 3 These are not specific to or required in the Remedial Targets Methodology Parameter Hydraulic conductivity Hydraulic gradient Effective porosity of aquifer Thickness of saturated aquifer Width of aquifer perpendicular to flow Distance to receptor Bulk density of aquifer materials Soi water partition co efficient Retardation factor of pollutant symbol K l n 1 20E 01 1 00E 02 1 00E 01 1 00E 01 2 00E 01 00E 01 1 65E 00 2 00E 01 331 unit md unitless fraction m m m afer l kg justification FP Groundwater flow velocity v WGW 1 39E 05 mis 1 20E 00 4 38E 02 miyear GW 3 60E 06 seconds 4 17E 01 1 14E 01 years Time for groundwater to reach receptor Rate of groundwater flow through aquifer Q 2 78E 04 mils 2 40E 01 8 76E 03 m fyear Contaminant flow velocity v contam 4 20E 08 mis 3 63E 03 1 32E 00 myear Time for contaminant to reach receptor t contam 1 19E 09 seconds 1 38E 04
35. p 1 806400 lant x di H 4 008 01 faimensionies x 17 Entry if specify partition coefficient option ES a 18 Soil water partion coetticies 2 006 00 i x 19 Entry for non polar organic chemicals option toc traction Koc itg zl Entry for io pka 3 Project data input toc fraction on th e l 29 Soil water partition coefficient used inLevel Assessment Kd 2 00600 Ka soecied vaiue Introduction E worksheet are lel Level 1 Remedial Target i automatically 3 Level 1 Remedial Target 6E 01 mgiky tfor Aymparison with soil analyses al i o transferred onto 35 01 for Is Complete each of the blue cells the subsequent Level 1 remedial target fym cells coloured blue will vary depending worksheets for soil as mg kg in soil F gt on which approach to modelling presented partitioning of the pollutant has been selected Other cells are blacked out Figure 4 2 Level 1 Soil worksheet Blue cells Data entry requirements i e blue cells are determined by the selected approach to modelling contaminant partitioning as described above It is only necessary to enter data in the blue cells Cells where data are not required will be blacked out Whichever partition coefficient option is selected it is still necessary to enter the following data Water filled soil porosity A
36. rom data input to Level 3 Soil Level 3 3 G Calc 2 Calculation of Level 3 remedial targets for groundwater using the time variant Domenico solution from data input to Level 3 Soil Remedial Targets Worksheet v3 1 User Manual 11 Data entry is only possible in the seven shaded worksheets and results of each calculation are presented on the relevant worksheet The remaining worksheets perform the calculations specified within the previous worksheets and are provided so that assessors can follow the mathematical calculations more easily It is neither possible nor necessary to modify or enter data into any of the calculation sheets In principle it is not necessary to open any of the calculation sheets to successfully use this worksheet Each worksheet is password protected and data may only be entered in specific cells which are colour coded blue brown or yellow Blue cells require data to be entered to either perform a specified calculation or to record site details Data may take the form of either site details as text on the Introduction sheet or values for identified parameters on all other sheets All blue cells must be completed for each assessment type Brown cells are pull down menus where options can be selected to allow the assessor to select a predefined option The origin or source of any data used in the worksheet should be recorded in the yellow cells Although failure to populate the Sour
37. ruary 2006 Enter name of site and address 12 13 Users of this worksheet showld always refer to the User Mansal to the Remedial Targets Methodology and to relevant guidance on UK te jaticy in oi i e 14 and policy in order to understand how this procedure should be applied in an appropriate context 16 OF Enter name of assessor who has completed the worksheet 5 Details to be completed for each assessment 7 28 Site Name Entes site mame 29 Site Addie Enter site address xn N Comploted by Enter user name R Ome Enter date Enter identifying run ane T number of model simulation a8 amp 28 Enter origin of target concentration such as an EQS or drinking water standard arr Ce wa Pee eA pir Enter pollutant name Enter date that assessment was Enter target completed concentration for subject pollutant Figure 4 1 Data entry required on Remedial Targets Introduction Worksheet Remedial Targets Worksheet v3 1 User Manual 13 4 3 Level 1 Soil worksheet The Level 1 Soil worksheet Figure 4 2 allows assessors to determine Level 1 remedial targets for contaminated soil Project information data site and contaminant details are automatically transferred to the Level 1 worksheet from the Introduction sheet Calculation of remedial targets cannot be performed unless the target concentration ha
38. s between groundwater and the aquifer matrix This value of Kg is likely to be different from that used in Level 1 to model partitioning between pore water and soils Calculated Ky should be based on relevant data e g foc values must relate to the aquifer materials and will therefore require different data from Level 1 assessments Values for dispersivity of contaminants in the aquifer can either be calculated from one of two equations or user defined values can be entered as follows 1 Calculated bases on flow path length Longitudinal dispersivity ax based on 0 1 x flow path length Transverse dispersivity az based on 0 01 x flow path length Vertical dispersivity ay based on 0 001 x flow path length 2 Calculated using a solution derived by Xu and Eckstein 1995 where a 0 83 logx az and ay are subsequently assumed to be 0 01 and 0 001 times the longitudinal dispersivity 3 User defined values for dispersivity may be obtained from tracer testing or experience of local hydrogeological conditions Remedial Targets Worksheet v3 1 User Manual 23 Blue cells Having selected which approaches to modelling contaminant fate and transport are appropriate it is necessary to populate the highlighted blue cells It should be remembered that data input on the Level 3 worksheet relates to behaviour of contaminants within the saturated aquifer Physico chemical data should be relevant to the aquifer matrix and are likely to be dif
39. s considered in only one direction i e downwards An alternative solution based on vertical dispersion in two directions up and down is also provided in the calculation sheets and could be used if the source is in the middle of the aquifer profile In most situations contaminants will enter groundwater after percolation through the unsaturated zone and vertical dispersion in only one direction is applicable It is generally assumed that biodegradation of organic contaminants only occurs in the dissolved phase since to pass through the cell membrane of micro organisms the molecule must first be in aqueous solution The worksheet provides a pull down menu that allows the user to select one of 1 Apply degradation rate to dissolved pollutants only This is applicable where the decay rate is obtained from laboratory observations of the contaminant in water In this case the rate constant is corrected in the spreadsheet by dividing it by the retardation factor R This results in degradation in the dissolved phase only being considered 2 Apply degradation rate to pollutants in all phases This is applicable to radioactive decay where the degradation rate is derived from field observations e g long term monitoring of groundwater or laboratory experiments have been undertake using groundwater and the aquifer matrix In this case the decay rate is applied to the whole system User defined Ky values must reflect the partitioning of contaminant
40. s previously been entered on the Introduction sheet Brown cells Assessors must first select which approach to the calculation of partition coefficients between soil matter and pore waters is appropriate Assessors have three options and must select from the pull down menu located on the brown coloured cell The three options are 1 Enter value for partition coefficient Kd 2 Calculate Kd for non polar organic chemicals based on K Koefa 3 Calculate Kd for polar ionic organic chemicals based on K Kuali 107e R 10 poe The Level 1 remedial target for soil is subsequently calculated as H C soil c k pA 14 Remedial Targets Worksheet v3 1 User Manual Al C mw v e e vaman pras v i Remedial Targets Worksheet Release 3 1 Environment Select approach o JERAS Level 1 Soil AY Agency to model partition Select the method of calculating the soil o o o ae water Partition Co efficient by using the pull coeffi Cl e nts fro m 6 down menu below 7 User specified value for partition coefficient th e p u l l dow n 8 Contaminant Pollutant menu ER Target concentration Cr Ki Input Parameters Variable Value 111 Sodreg of parameter value 12 Standard entry iced ence teeta auctor ng The source of ici each value should be documented on the worksheet and in associated reports i Water filed sol porosty w 1 00E 01 rraction Air sty ga 5 00E 02 rraction
41. t described has been prepared in MS Excel97 and no claim is made to its application in Excel2000 or other versions of MS Excel However attempts have been made to ensure that the equations included will allow error functions to be correctly calculated in Excel2000 4 Remedial Targets Worksheet v3 1 User Manual Contents Executive Summary Contents 1 2 3 4 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 5 6 Introduction Obtaining and installing the worksheet Overview Using the worksheet General Introduction worksheet Level 1 Soil worksheet Level 2 Soil worksheet Level 3 Soil worksheet Soil impact calculations worksheet Porosity calculator worksheet Level 3 Groundwater worksheet Sensitivity analysis Simple hydrogeological calculations worksheet References Remedial Targets Worksheet v3 1 User Manual N Oo oO fF 11 12 14 17 19 28 29 30 32 33 34 1 Introduction This User Manual has been prepared to assist users of the Environment Agency s Remedial Targets Worksheet v3 1 The worksheet produced in Microsoft Excel97 was produced to help risk assessors following the framework set out in the Environment Agency publication Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination Environment Agency 2006a This worksheet provides an update to earlier versions which were developed to support the framework set out in the document Methodology for the derivation of remedial targets for s
42. ters the calculations are most sensitive to and considered the anticipated variability in parameter values it is then possible to decide whether to revisit the assessment to collect more data on those parameter s to reduce uncertainty in the result Alternatively it may be appropriate to adopt conservative values for those sensitive parameters in order to ensure that the calculated remedial targets are protective of the environment Further guidance on assigning values to uncertain parameters in subsurface contaminant fate and transport modelling is provided in Environment Agency 2001c 32 Remedial Targets Worksheet v3 1 User Manual 6 Simple hydrogeological calculations worksheet In addition to the remedial targets worksheets a separate sheet titled Simple hydrogeological calculations is included Figure 6 1 This worksheet is not needed to complete any of the calculations described in the methodology but computes a range of standard calculations that are frequently used by hydrogeologists Data requirements for each calculation are described in the comments boxes noted by a red tick in the corner of relevant cells The calculations performed are summarised below Calculation Mathematical solution Groundwater flow velocity Vew K x i n Time for GW to reach to receptor tew n x distance K x i Volume of GW flowing through aquifer Q KxAxi Contaminant flow velocity Vc
43. ts in the grey box at the bottom of the screen Remedial targets are presented as soil concentration mg kg and leachable concentration mg l The spreadsheet also gives the calculated groundwater velocity retardation factor rate of contaminant movement decay rate ratio of contaminant concentration at compliance point to initial concentration Attenuation factor In addition the spreadsheet includes Graph Figure 4 7 showing variation in contaminant concentrations down gradient of the source expressed as C C Table giving calculated concentrations in groundwater between the source and the compliance point expressed as C C and C if starting concentration is entered Graph Figure 4 7 showing the predicted concentrations with distance from each of the three analytical solutions located to the right of the main data input area Note if a vertical or lateral offset is specified then the graph and table present contaminant concentrations along a line that is offset from the plume centre line Remedial Targets Worksheet v3 1 User Manual 27 he Lie yew poet Format Tool Data Entec Budget Process Ayes Excelerator Window HeD OSA SAY LRAT O SS cenit ea DMPO P Mice AeasAD se A BJU ESAO sh wim d A R g T U V w X Calculated relative concentrations for distance concemration graph Ogata Banks From calculation shout latre Rel concentration Concentration Mo units m 1 06400 2 436 02 CET
44. ubsequent sheets and can only be modified by changing the entry on the Introduction sheet 12 Remedial Targets Worksheet v3 1 User Manual The Introduction sheet also includes brief instructions on the use of the worksheet and a reminder that Microsoft Excel97 Tools must be enabled to allow it to calculate error functions and complimentary error functions The worksheet will not calculate Level 3 remedial targets for soil or groundwater unless MS Excel is set up to calculate these mathematical functions It is necessary to undertake a separate simulation for each pollutant present on a site and for each assessment type soil groundwater Only one substance and assessment should be considered in a single simulation Guidance on selecting appropriate target concentrations which are typically based on background water quality drinking water standards DWS or environmental quality standards EQS can be found in Remedial Targets Methodology Hydrogeological Risk Assessment for Land Contamination D e Cat Yew pomt Format Tooke Qata Entec dyst Process Agresso Cxcelerator tindow tte lalx ans So m aH Ox 43 ees _ A OP TENE E B SPRareGewssagr SEI Te TT Enable Excel functionality Gi Environment before using worksheet MY Agency 7 Hydrogeological risk assessment for land contamination 6 Remedial Targets Worksheet Release 3 1 9 Date of Workbook Issue Feb
45. urated aquifer immediately beneath the site in which contaminated recharge mixes with flowing groundwater Background concentration of contaminant Cu in groundwater up hydraulic gradient of the site When all of the blue cells have been completed click away on another cell and the remedial target will be calculated and reported in the grey cells at the bottom of the screen Three values are reported 1 2 3 The calculated dilution factor DF The calculated Level 2 remedial target for soil as mg kg for comparison with total soil concentrations The calculated Level 2 remedial target for soil as mg l for comparison with leachability test results If the concentration of soil leachate is Known it is also possible to predict the impact on groundwater after dilution has occurred 4 5 Level 3 Soil worksheet The Level 3 Soil worksheet Figure 4 4 is the final worksheet for assessing soil remedial targets in this package It builds on the results of Level 1 and Level 2 soils worksheets but additionally calculates the effects of advection and attenuation within the saturated aquifer Remedial Targets Worksheet v3 1 User Manual 19 z Eer Select option 3 Level 3 Soil i for calculating 5 Input Parameters ariable Yalue Unit Source Enter method of defining partition co efficient using pull down list rtiti 6 User specified value for partition coefficient pa tion
46. vironment Agency 2001c Guidance on assigning values to uncertain parameters in subsurface contaminant fate and transport modelling National Groundwater amp Contaminated Land Centre report NC 99 38 3 Solihull Environment Agency 2001d Guidance on the assessment and interrogation of subsurface analytical contaminant fate and transport models NGWCLC report NC 99 38 1 Solihull Environment Agency 2006a Remedial Targets Methodology Hydrogeological risk assessment for land contamination Environment Agency Bristol Environment Agency 2006b Groundwater Protection Policy and Practice 1 3 consultation version Bristol Environment Agency United States Environmental Protection Agency 1996 Soil screening guidance Technical background document EPA 540 R95 128 Xu M amp Eckstein Y 1995 Use of weighted least squares method in evaluating the relationship between dispersivity and field scale Groundwater 33 6 34 Remedial Targets Worksheet v3 1 User Manual We welcome views from our users stakeholders and the public including comments about the content and presentation of this report If you are happy with our service please tell us about it It helps us to identify good practice and rewards our staff If you are unhappy with our service please let us know how we can improve it Remedial Targets Worksheet v3 1 User Manual 35
47. y Figure 4 4 Level 3 Soil worksheet Data on site details are transferred directly from the Introduction worksheet The dilution factor DF is transferred directly from the Level 2 soil worksheet Brown cells There are four brown cells on the Level 3 Soil worksheet that need to be completed first in order to select the approach to simulating contaminant fate and transport The following options are available 1 Analytical solutions for contaminant transport e Ogata Banks solution e Steady state Domenico solution e Time variant Domenico solution 2 Approach to modelling degradation processes e First order biodegradation degradation rate applied to contaminants in the dissolved phase only e First order biodegradation or radioactive decay degradation rate applied to contaminant in both dissolved and sorbed phases 3 Option for specifying initial concentration Co e Use soil leaching concentration e Use soil concentration to calculate soil pore water concentration e Use unit concentration the calculation of the attenuation factor is based on the ratio of the initial concentration to the calculated concentration at the 20 Remedial Targets Worksheet v3 1 User Manual compliance point and consequently the calculated remedial target is independent of the initial concentration For the first two options the spreadsheet will calculate contaminant concentrations C in groundwater down hydraulic gradient of the site t
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