Model Description of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0

Transcription

1 Model Description of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0 REPORT DECISION SUPPORT FOR NUCLEAR EMERGENCIES

2 Version

3 Model Description of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0 Heinz Müller, Florian Gering, Gerhard Pröhl GSF - Institut für Strahlenschutz Ingolstädter Landstr.1 D Neuherberg heinz.mueller@gsf.de gering@gsf.de proehl@gsf.de December 1999 Management Summary This document contains a description of the model approaches used in the Aquatic Food chain and Dose Module FDMA as it is integrated in RODOS PV4.0. Program documentation and User Guide for FDMA are available as extra reports (RODOS(WG3)-TN(99)10 and RODOS(WG3)- TN(99)14) Version

4 Model Description of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0 Contents 1 Introduction Nuclide transfer via contaminated feeding water Irrigation of crops by contaminated water Parameters defining irrigation Interception of radionuclides by plant canopy Contamination of plants Contamination of animal products Contamination of feedstuffs and foodstuffs Dose calculation Internal dose from ingestion Calculation of collective doses References Appendix A: List of Symbols Appendix B: Default parameters for foodchain modelling in FDMA...20 Version

5 1 Introduction 1 Introduction The software package FDMA (Food Chain and Dose Module for Aquatic Pathways) is part of the "Real-time On-line Decision Support System" (RODOS). Within the RODOS system, FDMA is the module for simulating the transfer of radioactive material in food chains following contamination of water (used for drinking, animal feeding and irrigation of crops), and for the assessment of doses via some relevant aquatic pathways (internal exposure via ingestion of drinking water, agricultural products, and fish) to the population. Individual as well as collective doses can be estimated. Input to the aquatic food chain module are the time dependent concentrations of activity in different media: C fw (t) = activity concentration (Bq kg -1 ) in animal feeding water at time t C iw (t) = activity concentration (Bq kg -1 ) in irrigation water at time t C dw (t) = activity concentration (Bq kg -1 ) in drinking water at time t C fi (t) = activity concentration (Bq kg -1 ) in fish at time t These concentrations are provided by the RODOS Hydro module. The concentrations can be given at a maximum of 50 points in time after the beginning of the release. Linear interpolation of the (decaycorrected) activities is performed between these points in time to transfer the time array to that of the food chain calculations (presently 50 points in time during 100 years). If the points in time for which the contamination of water and fish is given do not cover the whole period for which dose assessments are made, the last given contamination (decay-corrected) is assumed for the following period. The methods applied to simulate the transfer of radionuclides in foodchains are essentially those of the radioecological model ECOSYS (Müller and Pröhl 1993). Also the Terrestrial Food Chain and Dose Module of RODOS, FDMT, is based on this model. Some parts of the model which are the same in FDMA and FDMT are described in more detail in the FDMT model description (RODOS(WG3)-TN(99)17). Version

6 2 Nuclide transfer via contaminated feeding water 2 Nuclide transfer via contaminated feeding water The methodology used is essentially the same as used for contamination of animal products after feeding of plant products which have been contaminated by deposition from the atmosphere in the terrestrial food chain module (RODOS(WG3)-TN(99)17). Thus only the main assumptions are given here. The contamination of animal products (milk, meat, eggs) resulting from the activity intake of the animals via contaminated feeding water considers the kinetics of the radionuclides within the animals. The amount of activity ingested by the animals is calculated from the time dependent concentration of activity in feeding water (which has been calculated in the RODOS Hydro module) and the water feeding rate: A () t = C () t I (2.1) fw, m fw fw, m where A fw,m (t) = activity intake rate of the animal m (Bq d -1 ) C fw (t) = activity concentration (Bq kg -1 ) in feeding water at time t I fw,m = water feeding rate (kg d -1 ) for animal m. The default water feeding rates assumed in FDMA are given in Table 1 in the Appendix. These intake rates are used as long as no specific information is available. The transfer of radionuclides from water intake into animal product l is described by the equilibrium transfer factor TF m and one or two exponentials using biological excretion rates: J T Cm( T) = TFm amj, Aam, ( t) λbmj, exp [ ( λbmj, + λr)( T t) ] dt j= 1 0 (2.2) where C m (T) = activity concentration (Bq kg -1 ) in animal product m at time T TF m = transfer factor (d kg -1 ) for animal product m J = number of biological transfer rates a mj = fraction of biological transfer rate j λ b,mj = biological transfer rate j (d -1 ) for animal product m. Version

7 2 Nuclide transfer via contaminated feeding water The default values for feed-animal product transfer factors and the biological half-lives (according to the transfer rates) applied in FDMA are the same as applied in the terrestrial food chain and dose module FDMT (see RODOS(WG3)-TN(99)17). It should be noted that the data base for the transfer of Zr, Nb, Te, Ru, Ba, Ce, Pu, Mn and Zn to animal food products is rather poor. Therefore, the uncertainty for these parameters is considerable. These parameters are often derived from short-time experiments; although, long-term components of the kinetics can contribute significantly to the transfer. Furthermore, the chemical forms of the tracers used in the experiments are often not representative of radionuclides released from nuclear facilities. However, the ingestion of contaminated animal food products does not contribute significantly to the total dose for these elements, and, in many cases, this pathway is negligible. Version

8 4 Contamination of feedstuffsand foodstuffs 3 Irrigation of crops by contaminated water 3.1 Parameters defining irrigation Irrigation is considered for each plant type individually. It is assumed that a certain fraction of the plants grown in an area are irrigated regularly during an irrigation season. The following model parameters describe the irrigation of one plant species: f irr = fraction of produced plants which is considered to be irrigated tb irr = begin of irrigation season (day of the year) te irr = end of irrigation season (day of the year) t irr = time (d) between two irrigation events R irr = amount of irrigation water (mm) applied per irrigation event These data are stored in the model parameter data base of the RODOS food chain and dose modules (see RODOS(WG3)-TN(99)10). They can be defined individually for each radioecological region. As a default, f irr is set to 1.0; this means, it is assumed that the whole amount of produced crops is irrigated. The default values for the begin and end of the irrigation period, tb irr and te irr, the frequency t irr of irrigation, the amount of water applied per irrigation event, R irr, and the amount of water applied during the whole irrigation period is given in Table 2 (see Appendix). 3.2 Interception of radionuclides by plant canopy For each irrigation event, the interception fraction f w,i of activity on the foilage of plant type i is assumed to be f LAI i S i ln 2, = 1 exp R R 3 S wi irr i irr (3.1) with LAI i = leaf area index of plant type i at time of irrigation S i = retention coefficient (mm) of plant type i If eqn (3.1) results in an interception fraction greater than 1.0, f w,i = 1.0 is taken. The leaf area index LAI i is strongly dependent on the season and on the climatological properties of the considered region. It is defined Version

9 3 Irrigation of crops by contaminated water individually for all crops and all radioecological regions in the model parameter data base (see RODOS(WG3)-TN(99)10). The values of the retention coefficient S i applied in the model are given in Table 3 in Appendix B. Three groups of elements (representatives are e.g. iodine, cesium, and strontium) are differentiated. For all other elements considered here, no data about S i are available; as a default, it is assumed that they behave similarly to cesium, except of barium for which the strontium data are used. 3.3 Contamination of plants The methodology used is essentially the same as used for plant contamination after a single deposit from the atmosphere in the terrestrial food chain module (see RODOS(WG3)-TN(99)17). Thus only the main assumptions are given here. The contamination of a plant product at time of harvest results from the direct contamination of the leaves and the activity transfer from the soil by root uptake and resuspension: Ci(t) = Ci,l(t) + Ci,r(t) (3.3) where C i (t) = total contamination of plant type i C i,l (t) = contamination of plant type i due to foliar uptake C i,r (t) = contamination of plant type i due to root uptake and resuspension. The activity concentration due to foliar uptake is calculated by adding up the contributions of all irrigation events during the growing season, while for root uptake the activity input to soil from all irrigation events in the past is considered. This means, if the activity concentration in irrigation water would be constant over many years, foliar uptake would be the same in every year while root uptake increases with time due to enrichment of activty in soil Foliar uptake of radionuclides Calculation of the contamination of plants must distinguish between plants which are used totally (leafy vegetables and grass) and plants of which only a special part is used (e.g., cereals and potatoes). Version

10 3 Irrigation of crops by contaminated water In the first case, the activity concentration C i,l at time of harvest is determined by the initial contamination of the plant at time of irrigation and the activity loss due to weathering effects (rain, wind), radioactive decay and growth dilution. For plants which are totally consumed excluding pasture grass, growth is implicitely considered because the activity deposited onto the leaves is related to the yield at harvest. The concentration of activity is given by: Nirr A i,n Cil, = exp ( ( λw + λr) tn) (3.4) Y n= 1 i where C i,l = concentration of activity in plant type i at time of harvest N irr = number of irrigation events per year: N irr = int (te irr - tb irr ) / t irr A i,n = total deposition (Bq m-2) onto plant type i due to the plant's leaf area index at time of irrigation event n Y i = yield (kg m -2 ) of plant type i at time of harvest λ w = loss rate (d -1 ) due to weathering λ r = radioactive decay rate (d -1 ) t n = time span between irrigation event n and harvest (d). The approach for pasture grass is somewhat different because of its continuous harvest. Here, the decrease in activity due to growth dilution is explicitely considered. Furthermore, for elements which are mobile within the phloem (e.g., I or Cs), the translocation to the roots, and the subsequent remobilization is taken into account (see The concentration of activity in hay and grass silage is taken as a weighted mean concentration in grass harvested between begin and end of hay harvesting period. For plants which are only partly used for animal feeding or human consumption, the translocation from the leaves to the edible part of the plant has to be considered. This process is strongly dependent on the physiological behavior of the element considered: it is of importance for mobile elements such as I or Cs, but it does not occur with immobile elements like Sr. In the latter case, only the direct deposition onto the edible parts of the plants plays a role. Furthermore, the amount of translocated activity is highly dependent on the timespan t between deposition and harvest. The translocation process is quantified by the translocation factor T i ( t) which is defined as the fraction of the activity deposited on the foliage being transferred to the edible parts of the plants until harvest. Version

11 3 Irrigation of crops by contaminated water It is dependent on the element, the plant type, and the time between deposition and harvest. The concentration of activity for plant type i at time of harvest is given by Nirr A i Cil, = Ti( tn) exp( λ r tn) (3.5) Y n=1 i where T i ( t n ) = translocation factor for plant type i, for a time span t n between irrigation event n and harvest, Y i = yield of edible parts of plant type i, t n = time span between irrigation event n and harvest (d). and other symbols as defined earlier. A detailed time resolution is considered only during the first two years after the accident; in later time periods only an annual average is used Root uptake of radionuclides The estimation of the root uptake of radionuclides assumes that the radionuclides are well mixed within the entire rooting zone. The concentration of activity due to root uptake is calculated from the concentration of activity in the soil using the transfer factor TF i which gives the ratio of concentration of activity in plants (fresh weight) and soil (dry weight): C i,r (t) = TF i C s (t) (3.6) where C i,r (t) = concentration of activity (Bq kg -1 )in plant type i due to root uptake at time t, TF i = soil to plant transfer factor for plant type i, C s (t) = concentration of activity (Bq kg -1 ) in the root zone of soil at time t. If the deposition occurs during the growing period less than 50 days before harvest, a reduced root uptake is assumed for the first harvest. The reduction factor is the ratio of the time span from deposition to harvest and 50 days (or the length of the whole growing period if it is less than 50 days). Since the soil to plant transfer factors TF i depend on the soil type, within each radioecological region four different soil types can be Version

12 3 Irrigation of crops by contaminated water defined and according TF i factors can be given for each of these soil types in the model parameter files. The RODOS data base assigns a soil type index to each of the grid points (locations) so that for each location a soil to plant transfer factor according to the local soil type can be used in the calculations. The assessment of the concentration of plant available activity in the root zone of soil has been changed since the last version of FDMT according to a suggestion of Fesenko et al. (1998) in order to allow a better adaptation to the conditions of Russia and other East European regions. In addition to fixation (sorption) of radionuclides on soil particles - which was already in the model - now desorption from soil particles is considered. This is done by setting up two compartments representing the activity available and not available for plants. This model approach can be solved analytically (Fesenko et al., 1998). Thus, the concentration of activity in the root zone of soil is given by N A s,n C s (t) = n= 1 L δ {a s exp(-b 1 t n ) + (1-a s ) exp(-b 2 t n )} exp(-λ r t n ) (3.6) where A s,n = total deposition to soil (Bq m -2 ) at irrigation event n N = total number of irrigation events before time t L = depth of root zone (m) δ = density of soil (kg m -3 ) t n = time span between irrigation event n and time t (d). and the coefficients a s = (λ f - λ d + λ s + R) /(2 R) b 1 = (λ f + λ d + λ s + R) / 2 b 2 = (λ f + λ d + λ s - R) / 2 where R = {(λ f - λ d + λ s )² + 4 λ f λ d } ½ λ f = rate of fixation (d -1 ) of the radionuclides in the soil. λ d = rate of desorption (d -1 ) of the radionuclides from the soil λ s = rate of activity decrease due to migration out of the root zone (d -1 ) If the desorption rate λ d is set to zero, then this approach is the same as that used in earlier versions. Version

13 3 Irrigation of crops by contaminated water Resuspension Besides transfer of activity from soil to plants by root uptake, deposition of resuspended soil particles onto the plants is considered. Since plant contamination due to resuspension can be considered as proportional to the activity in soil, it is quantitatively expressed by a resuspension factor which is added to the soil-plant transfer factor. The resuspended soil fractions are primarily silt and clay. The concentration of activity in these soil fractions might be increased considerably compared to the mean soil contamination due to the strong binding of many radionuclides to clay minerals. This is taken into account in the model by using an enrichment factor for resuspension f r which is multiplied with the resuspension factor. This factor is dependent on the radionuclide and on the soil type. A more detailed description of the modelling approaches and the default values of the parameters is given in the FDMT model description (RODOS(WG3)-TN(99)17). Version

14 3 Irrigation of crops by contaminated water 3.4 Contamination of animal products FDMA considers the activity intake by applying feedstuffs which have been contaminated by irrigation with contaminated water. The method applied for calculating the resulting activity concentration in animal products is essentially the same as described in Chapter 3.1. The amount of activity ingested by the animals is calculated from the concentration of activity in the different feedstuffs and the feeding rates: K m A () t = C () t I () t am, k km, k= 1 where A a,m (t) = activity intake rate of the animal m (Bq d -1 ) K m = number of different feedstuffs fed to the animal m C k (t) = activity concentration (Bq kg -1 ) in feedstuff k I k,m (t) = feeding rate (kg d -1 ) for feedstuff k and animal m. (3.8) Plants or products processed from plants or animal products (see eqn 4.1 below) can be considered to be feedstuffs for animals. The default feeding diets assumed in FDMA are summarised in Table 4 in Appendix B. These intake rates are used as long as no specific information is available. However, for a realistic dose assessment in emergency situations, the feeding regimes have to be adapted to the season-dependent feed compositions of the specific region under consideration. FDMA can consider complex time-depending feeding diets consisting of a mixture of up to 8 different feedstuffs. In addition to the intake of activity with contaminated feedstuffs, FDMA also considers the radionuclide intake due to soil ingestion. The soil intake of animals varies widely depending on the grazing management and the condition of the pasture. Taking into account the feeding of mechanically prepared hay and silage during winter and an intensive grazing regime on well fertilised pasture, a mean annual soil intake of 2.5% of the grass dry matter intake seems to be appropriate. This nuclide-independent value is equivalent to a soil-plant transfer factor of 5x10-3 ; it is added to the transfer and resuspension factor in FDMA. This means that, for all elements with a transfer factor lower than 5x10-3, soil-eating is the dominating long-term pathway for the contamination of milk and meat from grazing cattle, presuming that resorption in the gut is the same for soil-bound and plant-incorporated radionuclides. The transfer of radionuclides from fodder into the animal products is calculated as given in Chapter 4.1 (eqn. 4.1). Version

15 3 Irrigation of crops by contaminated water 4 Contamination of feedstuffs and foodstuffs The contamination of animal products via contaminated feeding water and those of plant and animal products via irrigation as described in the last two chapters is valid for raw products, i.e. animal products at time of slaughtering and plant products at time of harvest. The contamination of human foodstuffs is calculated from the contamination of these raw products taking into account the activity enrichment or dilution during processing and culinary preparation as well as processing and storage times. The concentration of activity in product k (feed- or foodstuff) is calculated from the raw product by C k (t) = C k0 (t-t pk ) P k exp(-λ r t pk ) (4.1) where C k (t) = activity concentration (Bq kg -1 ) in product k ready for consumption at time t C k0 (t) = activity concentration (Bq kg -1 ) in the raw product at time t P k = processing factor for product k λ r = radioactive decay constant (d -1 ) t pk = storage and processing time (d) for product k. The default processing factors applied in FDMA are the same as those given in the documentation of the terrestrial food chain and dose module FDMT. For strontium, iodine and cesium there is a relatively good data base available while for all other elements due to lack of data the default values are applied. The storage times are considered to be the mean time period between the harvest and the beginning of product consumption. It should be noted that these storage and processing times may change considerably in the case of radioactive contamination if decontamination is a goal. Version

16 5 Dose calculation 5 Dose calculation 5.1 Internal dose from ingestion The intake of activity by man is calculated from the time-dependent concentrations of activity in foodstuffs and the human consumption rates: K A () t = C () t V () t h k k k= 1 where A h (t) = human intake rate (Bq d -1 ) of activity K = number of foodstuffs considered C k (t) = concentration of activity (Bq kg -1 ) of foodstuff k V k (t) = consumption rate (kg d -1 ) of foodstuff k. (5.1) In FDMA, age-dependent consumption rates are applied. The dietary habits can also be assumed to be time-dependent which allows the simulation of dietary changes during or after an accidental situation. The foodstuffs are assumed to be locally produced, i.e. their concentration of activity is assumed according to the input data of contamination of air and precipitation. Importation of foodstuffs from other regions with different levels of contamination can be taken into account by applying multiplicative correctional factors to the consumption rates for single foodstuffs. As an example, average German consumption rates for the age groups 1, 5, 10, 15 y and adults are given in Table 5. For leafy vegetables, it is assumed that the consumption rate in summertime is higher than the mean rate, and in wintertime, only a small fraction of the consumed vegetables is harvested outdoors (the rest is produced in greenhouses or imported from abroad). Therefore, from May through October, a factor of 1.5 and from November through April, a factor of 0.1 is applied to the average consumption rates for leafy vegetables. The dose D Ing (T) due to ingestion of contaminated foodstuffs within the time T after deposition is given by T D Ing (T) = A h (t g Ing(t) dt (5.2) 0 where D Ing (T) = ingestion dose (Sv) g Ing (t) = age-dependent dose factor for ingestion (Sv Bq -1 ). Version

17 5 Dose calculation The dose factors applied in FDMA were calculated using the NRPB internal dosimetry program PLEIADES, which is consistent with publications ICRP-68, ICRP-72, and IAEA BSS. They give the dose commitment for an individual from its age at ingestion until the age of 70 y. For activity intake above the age of 20 y, the 50-year dose commitment is calculated. 5.2 Calculation of collective doses The assessments of collective doses in FDMA can only be regarded as rough estimations of the real collective doses due to the limited input information. Different approaches are used for collective doses from consumption of contaminated drinking water and fish on the one hand, and from consumption of agricultural products which are contaminated by animal feeding water and irrigation on the other hand Agricultural products: The collective dose at a location (i.e. grid point of calculation in RODOS) due to consumption of foodstuffs contaminated by animal feeding water or irrigation is based on the amount of foodstuffs produced at that location. Only that part of products which is consumed by humans is considered. Collective dose is estimated as that effective dose equivalent which arises if these products are eaten by adults, no matter where they are eaten (this might be by people living at the considered location, or somewhere else). Collective doses can be calculated only for those foodstuffs for which production data are available. Since it can be expected that production data will never be available for all produced foodstuffs, summing up the collective doses for all foodstuffs considered seems to be not very useful; the result would be a more or less arbitrary number. The contamination of animal feeding water and irrigation water is given by the Hydro module at time of application to the animal or crop, therefore subsequent radioactive decay until harvest or slaughtering and during processing and storage of the products is considered. For a given location, collective dose from ingestion of raw product k in the time period from deposition up to time T is calculated as Col D ( T) = g PR exp( t ) C ( t) dt Ing Ing, a k λ r pk k0 0 T (5.3) Version

18 5 Dose calculation with DIng Col ( t) = collective dose from ingestion of foodstuff (raw product) k g Ing,a = ingestion dose factor (Sv Bq -1 ) for adults PR k = production rate of foodstuff k (kg a -1 ) t pk = storage and processing time (d) for product k C k0 (t) = activity concentration (Bq kg -1 ) in the raw product at time t If a certain raw product is used to process more than one foodstuff, then the shortest storage and processing time t pk is used in this calculation. Further, loss of activity from the food chain during food processing and culinary preparation is not considered in this estimation since production data are given for raw foodstuffs, and there is no information on processing of them. For these reasons, the resulting collective dose for a (raw) foodstuff has to be regarded as an upper limit Drinking water and fish: For drinking water and fish the production rates are given for water sources, not for grid cells of the RODOS calculation grid. Water sources can be e.g. lakes, parts of a river, or water processing plants. The contamination of drinking water and fish is given by the Hydro module at time of consumption, i.e. no additional processing period is considered. For a given water source, the collective dose from ingestion of product k (drinking water or fish) in the time period from deposition up to time T is calculated as Col D ( T) = g PR C ( t) dt Ing T Ing, a k k0 0 (5.4) with DIng ( t) = collective dose from ingestion of foodstuff (raw product) k g Ing,a = ingestion dose factor (Sv Bq -1 ) for adults PR k = production rate of foodstuff k (kg a -1 ) C k0 (t) = activity concentration (Bq kg -1 ) in the product k at time t Version

19 6 References 6 References International Commission on Radiological Protection. Report of the task group on reference man. Oxford: Pergamon Press; ICRP Publication 67, Müller, H., Pröhl, G.: ECOSYS-87: A Dynamic Model for Assessing Radiological Consequences of Nuclear Accidents. Health Physics 64(3), (1993) (1993) RODOS(WG3)-TN(99)10: Heinz Müller, Florian Gering, Stephan Hübner: Documentation of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0. Final December 1999 RODOS(WG3)-TN(99)14: Florian Gering, Stephan Hübner, Heinz Müller: User Guide of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0. Final December 1999 RODOS(WG3)-TN(99)17: Heinz Müller, Florian Gering, Gerhard Pröhl: Model description of the terrestrial food chain and dose module FDMT in RODOS PV4.0. Final December 1999 Version

20 7 Appendix A 7 Appendix A: List of Symbols δ λ b λ b,mj λ f λ r λ s λ t λ w t irr Q a a 1,a 2 a mj = density of soil (kg m-3) = dilution rate by increase of biomass (d-1) = biological transfer rate j (d-1) for animal product m = rate of fixation (d-1) of the radionuclides in the soil = radioactive decay rate (d-1) = rate of activity decrease due to migration out of the root zone (d-1) = rate of activity decrease (d-1) due to translocation to the root zone = loss rate (d-1) due to weathering = time (d) between two irrigation events = water content of soil (g g-1) = fraction of activity translocated to the root zone = contribution fractions of the migration rates = fraction of biological transfer rate j A a,m (t) = activity intake rate of the animal m (Bq d -1 ) A g = total activity deposited onto grass (Bq m -2 ) A h (t) = human intake rate (Bq d -1 ) of activity A i = total deposition onto plant type i (Bq m -2 ) A s = total deposition to soil (grassland) (Bq m -2 ) A w = total wet deposition (Bq m -2 ) C k (t) = activity concentration (Bq kg -1 ) in feed or foodstuff k Ciw (t) = activity concentration (Bq kg-1) in irrigation water at time t Cdw (t) = activity concentration (Bq kg-1) in drinking water at time t Cfi (t) = activity concentration (Bq kg-1) in fish at time t C i,r (t) = concentration of activity (Bq kg -1 )in plant type i due to root uptake at time t after deposition C s (t) = concentration of activity (Bq kg -1 ) in the root zone of soil at time t = dose (Sv) from ingestion of contaminated foodstuffs D Ing Version

21 7 Appendix A D Col ( t ) = collective dose from ingestion up to time t f irr f w,i Ing = fraction of produced plants which is considered to be irrigated = interception fraction for wet deposition onto plant type i g Ing = dose factor for ingestion (Sv Bq -1 ) I fw,m = water feeding rate (kg d-1) for animal m. I k,m (t) = feeding rate (kg d -1 ) for feedstuff k and animal m k = normalization factor for calculation of LAI of grass from yield (m 2 kg -1 ) K d = distribution coefficient (cm 3 g -1 ) K m L LAI g LAI i P k R g Rirr S i t birr t eirr t pk = number of different feedstuffs fed to the animal m = depth of root zone (m) = leaf area index of grass at time of deposition = leaf area index of plant type i at time of deposition = processing factor for product k = reduction factor for staying at different locations (external exposure from ground) = amount of irrigation water (mm) applied per irrigation event = retention coefficient of plant type i (mm) = begin of irrigation season (day of the year) = end of irrigation season (day of the year) = storage and processing time (d) for product k TF i = soil to plant transfer factor for plant type i TF m = transfer factor (d kg -1 ) for animal product m T i ( t) = translocation factor for plant type i v gi = dry deposition velocity for plant type i (m s -1 ) V k (t) = consumption rate (kg d -1 ) of foodstuff k Y g = yield of grass at time of deposition (kg m -2 ) Y i = yield of edible parts of plant type i Version

22 8 Appendix B 8 Appendix B: Default parameters for foodchain modelling in FDMA Animal Intake rate (kg d -1 ) Lactating cow 70 Lactating sheep 9 Lactating goat 13 Beef cattle 28 Calf 2.9 Pig 3.0 Lamb 5 Hen, chicken 0.09 Roe deer 4 Table 1: Water feeding rates I fw,m for animals: default values for Central European conditions. Irri gation period Irrigation total Plant begin end duration frequency events amount amount (d) (d) (mm) (mm) grass 01. May 15. Sep maize 05. Jun 15. Aug potatoes 05. Jun 15. Aug beet 15. Jun 10. Sep wi-barley 01. May 15. Jun sp-barley 15. May 15. Jun wi-wheat 15. May 15. Jun sp-wheat 15. May 15. Jun rye 15. May 15. Jun oats 15. May 15. Jun leafy vegs. 01. Mai 15. Sep root vegs. 01. Jun 30. Sep fruit vegs. 01. Jun 31. Aug fruits 15. May 30. Sep berries 15. May 31. Aug Table 2: Default data for irrigation of different crop species Version

23 8 Appendix B Retention coefficient (mm) Plant species I, Tc Ce, Cs, Mn, Na, Nb, Pu, Rb, Ru, Sb, Te, Zr Grass, cereals, maize Ag, Am, Ba, Cm, Co, La, Mo, Nd, Np, Pr, Rh, Sr, Y Other plants Table 3: Retention coefficients S i for different plants and elements used for calculation of wet interception Animal Feedstuff Intake rate (kg d -1 fresh weight) Lactating cow grass 70 a Lactating sheep grass 9 a Lactating goat grass 13 a Beef cattle maize silage 28 Calf milk substitute 2.9 Pig winter barley 3.0 Lamb grass (extensive) 5 a Hen, chicken winter wheat 0.09 Roe deer grass (extensive) 4 a a Values given are for the vegetation period; during the winter an equivalent dry matter intake with hay or silage is assumed Table 4: Feeding diets Ik for animals: default values for Central European conditions. Version

24 8 Appendix B Consumption rates (g d -1 ) Foodstuff for age group 1 a 5 a 10 a 15 a adults Spring wheat, whole grain Spring wheat, flour Winter wheat, whole grain Winter wheat, flour Rye, whole grain Rye, flour Oats Potatoes Leafy vegetables Root vegetables Fruit vegetables Fruit Berries Milk Condensed milk Cream Butter Cheese (rennet) Cheese (acid) Beef (cow) Beef (cattle) Veal Pork Chicken Roe deer Eggs Beer Table 5: Age-dependent German consumption rates V k as applied as default in FDMA Version

25 Document History Document History Document Title: Model Description of the Aquatic Food Chain and Dose Module FDMA in RODOS PV4.0 RODOS number: Version and status: Version 1.2 (final) Authors/Editors: H.Müller, F.Gering, G. Pröhl Address: GSF - Institut für Strahlenschutz, Ingolstädter Landstr. 1, D Neuherberg heinz.mueller@gsf.de Issued by: Heinz Müller History: Version 1.0 (draft) June 1999 Version 1.1 (draft) October 1999 Version 1.2 (final) December 1999 Date of Issue: December 1999 Circulation: File Name: FdmaModel.doc Date of print: May 24, 2004 Version