Plant uptake and human health risks from dietary exposure

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1 Plant uptake and human health risks from dietary exposure Organic non-ionised chemicals Ondřej Mikeš

2 1. Pathways between soil/plant/air 2. Building model 3. Different crops 4. Chemicals 5. Dietary exposure

3 Air/shoot exchange Phloem transport Particle deposition Trapp (with permission) Direct contact with soil Sorption and desorption Xylem translocation Evaporation Transpiration stream

4 Roots = take up water and solutes Stems = transport water and solutes Xylem = dead water pipe Phloem = living sugar pipe Leaves = transpire water and take up gas Fruits = sink for phloem and xylem

5 1. Pathways between soil/plant/air 2. Building model 3. Different crops 4. Chemicals 5. Dietary exposure

Soil pore water What is in the solution?

1 (EU,1996) (Abdul, Piwoni, Karickhoff, Molecular

6 Soil pore water What is in the solution? Bioavailable C W /C Soil = K WS = ρ wet /(Kd x ρ dry + P W ) Kd=K OC xoc sorption to soil (organic matter) LogK OC =0.81 logk OW +0.1 (EU,1996) (Abdul, Piwoni, Karickhoff, Molecular connectivity ) K WS C W -in mg/l, C Soil -bulk mg/kg, OC-kg/kg, ρ-kg/l, Pw-pore water fraction in bulk soil

7 Roots Can t see them Livers of the Earth Monocotyledon all cereals Dicotyledon- all root vegetables Root hairs Bioavailability

Diffusion and advection High surface equilibrium assumption K RW =W R +L R a K b OW Change of concentration in roots = + uptake with water transport to shoots dilution by growth or metabolism (rate

8 Diffusion and advection High surface equilibrium assumption K RW =W R +L R a K b OW Change of concentration in roots = + uptake with water transport to shoots dilution by growth or metabolism (rate k) dc R /dt = + C W Q/M R C Xy Q/M R kc R where k - growth + metabolism rate [d - 1 ] C Xy - concentration in xylem = C R /K RW C W - concentration in soil pore water Q - transpiration stream (L/d) M - Mass of the roots (kg)

9 Translocation upwards TSCF = Transpiration stream concentration factor C Xy /C W, TSCF 1 C Xy - outflux from roots = influx to stem or leaves

deposition Soil attached Phloem transport K LW =W L +L L a K OWb - leaf/water K LA =K LW /K AW AW - leaf hang

10 Leaves Leaves are plant material, like roots. But they do not hang in soil nor in water. Leaves hang in air. Uptake from roots with transpiration water Uptake from air (conductance m/s) Loss to air Degradation Particle deposition Soil attached Phloem transport K LW =W L +L L a K OWb - leaf/water K LA =K LW /K AW AW - leaf hang in the air dc L /dt= + C R (Q/M L xk RW ) + C A (A L xg/m L ) - C L (A L xgx1000lm -3 /K LA xm L ) - C L (k L )

11 1. Pathways between soil/plant/air 2. Building model 3. Different crops 4. Chemicals 5. Dietary exposure

12 Trapp (with permission) Different crops phloem, influx to fruits, particles, turtuousity BUT similar model structure For more information ask me or mail directly to Stefan Trapp

13 1. Pathways between soil/plant/air 2. Building model 3. Different crops 4. Chemicals and model 5. Dietary exposure

14 Standard Plant uptake model Research Centre for Toxic Compounds in the Environment, Masaryk University Yellow-chemicals entry, blue-concentration, light brown-soil entry, light blue- root entry, dark greenleaves, orange- fruits, grey- calculation (don't touch), white-data entry and results

15 Exercise 1 Create 2 graphs for Croot, leaf, corn(steady-state) when: Cair= mg/m 3,Csoil=1mg/kg,OC=0,02 1 st Kaw=1.10-4, log Kow=-1,2,4,7 2 nd log Kow=2, Kaw= 10-9,10-7,10-5,10-2,10 1 logkow Croot Cleaf Ccorn Kaw 1,00E-09 1,00E-07 1,00E-05 1,00E-02 1,00E+00 Croot Cleaf Ccorn

16 Results log Cplant (mg/kg) 1,00E+02 1,00E+01 logkow 1,00E Croot Cleaf Ccorn 1,00E-01 1,00E-02 1,00E-03

17 Results log Cplant (mg/kg) 1,00E+02 1,00E+01 1,00E+00 1,00E-01 Croot Cleaf Ccorn logkaw ,00E-02 1,00E-03 1,00E-04 1,00E-05 1,00E-06

18 Output from the model SOIL to LEAVES Research Centre for Toxic Compounds in the Environment, Masaryk University Csoil=1 mg/kg Cair = 0 mg/m 3 OC= 2% Low to moderate Kow Low to moderate Kaw 1.00E+02 Drin s, HCH s, low molecular PAH s 1.00E+01 leaves/soil 1.00E E-01-7 volatility 1.00E-02-3 log Kaw hydrophobicity log Kow

Output from the model AIR to LEAVES Csoil=0 mg/kg Cair = 1E-6 mg/m 3 OC= 2% High to moderate Kow Low to moderate Kaw 1.00E-01 1.00E-02 1.00E-03 1.00E-04 1.00E-05 leaves/air 1.

19 Output from the model AIR to LEAVES Csoil=0 mg/kg Cair = 1E-6 mg/m 3 OC= 2% High to moderate Kow Low to moderate Kaw 1.00E E E E E-05 leaves/air 1.00E-06 High molecular PAH s Toxaphene, Chlordane, BDE-99, DDX, Mirex, Highly chlorinated PCB s 1.00E E E E-10-3 log Kaw log Kow 8 hydrophobicity Research Centre for Toxic Compounds in the Environment, Masaryk University volatility

20 1. Pathways between soil/plant/air 2. Building model 3. Different crops 4. Chemicals 5. Dietary exposure

Health risk Exposure measured or modelled

21 Health risk Exposure measured or modelled Toxicity usually measured NOEL/UF Dosis facit venumum Effect = Exposure x toxicity Oral exposure Dermal exposure Inhalation exposure Dietary exposure usually US-EPA guidelines measured food concentration needed

22 Data collection Needed: log K OW, K AW, metabolism const., C SOIL,C AIR,C WATER, OC (Env. Journals) Phys-chem Databases: Mackay, Rippen,Verschueren QSAR models : EPISuite,ACD/iLab,MOLPRO...

Exercise 2 Dietary risk for beta-hch and BDE-99

databases 4 th - consumption data (national

23 Exercise 2 Dietary risk for beta-hch and BDE-99 : 1 st - phys-chem from EPI-Suite programme 2 nd - environmental concentrations (lit.-given) 3 rd - toxicology profiles US-EPA databases 4 th - consumption data (national Czech survey) 5 th - plant and risk calculation CAS CAS

Input Data log K OW K AW Ref. BDE-99 6,84 4,82.10-5 EPISUITE β-hch 4,14 2,10.10-4 EPISUITE C SOIL (WW) (mg/kg) 2,63.10-6 Hassanin 2004 3,41.10-5 Mikes 2009 C AIR (mg/m 3 ) 2,20.10-8, AMAP 2003 1,90.

24 Input Data log K OW K AW Ref. BDE-99 6,84 4, EPISUITE β-hch 4,14 2, EPISUITE C SOIL (WW) (mg/kg) 2, Hassanin , Mikes 2009 C AIR (mg/m 3 ) 2, , AMAP , , Mikes 2009 SF (mg/kg-day) -1 RfD (mg/kgday) -1 Ref. -4 IRIS- - 1,0.10 US_EPA IRIS- 1,8 - US_EPA Women-adult (95%-percentile) units INroot 1,4 g/kg bw/day INleaf 1,94 g/kg bw/day INcorn 5 g/kg bw/day Weight 67,7 kg Corg=0,014 (average Czech soil) (1,4%) concentration_table/generic_tables/index.htm

25 Risk calculation BDE-99 Food beta-hch (kg/kg bw BDE-99 consumption β-hch consumption (mg/kg) (mg/kg) day) (mg/kg bw day) (mg/kg bw day) Croot Cleaf Ccorn SUMA 6,27E-09 2,37E-04 4,76E-05 9,97E-06 1,76E-03 1,35E-03 0,0014 0, ,005 8,78441E-12 4,59799E-07 2,38041E-07 6,97849E-07 1,39624E-08 3,40977E-06 6,74114E-06 1,01649E-05 BDE-99 (non-carc): Risk=CDI/RfD CDI= 7E-7 RfD= 1E-4 Risk= 7E-3 No risk, but! β-hch (carc): Risk= 1- exp (-CDI * SF) CDI= 1E-5 SF= 1,8 Risk= 1,8E-5 Risky, but!

Czech dietary uptake Potential fruit model + water concentration 450 400 350 300 250 200 150 100 50 0 Average consumption in g/day in Czech republic, Ruprich et al.

26 Czech dietary uptake Potential fruit model + water concentration Average consumption in g/day in Czech republic, Ruprich et al., % of consumption are plants Fruit model Potato model Leafy model Root model Water Milk products Beer Cereals(bread,corn,rice) Fruits (+tomatoes,beans) Lemonade (+juice,syrup) Meat Potatoes (+fries,crisps) Leafy vegetables Wine Root vegetables

Some limitations 1. Non-ionic ionic diffusion follows Nernst- Planck equation 2. Metabolism (Michaelis-Menten kinetics usually more soluble compounds) 3. Growth is considered exponential 4.

27 Some limitations 1. Non-ionic ionic diffusion follows Nernst- Planck equation 2. Metabolism (Michaelis-Menten kinetics usually more soluble compounds) 3. Growth is considered exponential 4. TSCF calculations 5. Easier approach? Travis and Arms (1988) log BV (dry wt) = log KOW 6. On-spot measuring, exposure studies, worst case scenario 7. Always be careful with interpretation risk analysis results Can we eat this fruit or is it too polluted, Eva? Don t worry it s below legal standard, Adam. Trapp (with permission)

28 Other dietary/crop models? Paterson and Mackay(1994), Chiou(2001) Fantke(2011), Ionic chemicals (MAMI, MAMI,Trapp, 2009) Heavy metals (CSOIL,CLEA,FIAM, CSOIL,CLEA,FIAM,Hough, 2001) Breast milk (US-EPA,2008 EPA,2008, Trapp, 2009)

29 Knowledge to go Semi-volatile chemicals Low Kow (root uptake) High Kow (shoot uptake) Model is not predicting exact concentration guide to insight and design experiments Modelling is easy Not only air is important Czech drinks a lots of beer

30 Question time

Appendix C Risk Calculations Western Margin of Northern Plumes

Appendix C Risk Calculations Western Margin of Northern Plumes Appendix C Calculations Western Margin of Northern Plumes Consolidated Human Health Assessment - 2010 General Parameters Air s During Irrigation (Reference: Guidelines for the Assessment and Management