The Relevance of Soil for Human Exposure to Dioxins Frank NEUGEBAUER, Nina LOHMANN, Olaf PAEPKE Eurofins GfA Lab Service GmbH, Hamburg, Germany www.dioxins.de
PCDDF: Toxicology, Importance and Sources 2
Dioxins (PCDD/F) Dioxins is the common name for two groups of polyhalogenated aromatics O O Cl x O Cl y Cl x x,y = 0...4; x+y>0 Cl y x,y = 0...4; x+y>0 Polychlorinated Dibenzo-(p)-dioxins (PCDD) 75 possible congeners 7 toxic congeners (2,3,7,8 chlorosubstitution) Polychlorinated Dibenzofurans (PCDF) 135 possible congeners 10 toxic congeners (2,3,7,8 chlorosubstitution)
TEQ-Scheme: toxicity evaluation Substance LD 50 [µg/kg] Tetanus toxine 0,0001 Botulism toxine 0,0003 Diphthery toxine 0,3 2,3,7,8-Tetrachlordibenzo-p-dioxin 1 Saxitoxin (mussel toxin) 8,9 Aflatoxin B 1 (Mycotoxin) 10 Kurare (pflanzl. Alcaloid mixture) 500 Strychnine (plant alcaloid) 500 Nikotin (Alcaloid of the tobacco plant) 1000 Natrium cyanide 9800 (Source: VIS Bayern 2005) 4
Toxicity Equivalent Factors (TEF) acc. to WHO 1998 / 2005 Highest toxicity Lowest toxicity 5
Toxicity EQuivalents (TEQ) calculation All results in pg/g Compound Result WHO-TEFs Single TEQ 2.3.7.8- Tetra-CDD 0,31 1 0,31 1.2.3.7.8- Penta-CDD 0,64 1 0,64 1.2.3.4.7.8- Hexa-CDD 0,16 0,1 0,016 1.2.3.6.7.8- Hexa-CDD 0,5 0,1 0,054 1.2.3.7.8.9- Hexa-CDD 0,33 0,1 0,033 1.2.3.4.6.7.8- Hepta-CDD 4,7 0,01 0,0469 1.2.3.4.6.7.8.9- Octa-CDD 25 0,0001 0,002488 2.3.7.8- Tetra-CDF 2,22 0,1 0,222 1.2.3.7.8- Penta-CDF 0,34 0,05 0,017 2.3.4.7.8- Penta-CDF 0,34 0,5 0,17 1.2.3.4.7.8- Hexa-CDF 0,12 0,1 0,012 1.2.3.6.7.8- Hexa-CDF 0,07 0,1 0,007 1.2.3.7.8.9- Hexa-CDF n.d. 0,1-2.3.4.6.7.8- Hexa-CDF 0,11 0,1 0,011 1.2.3.4.6.7.8- Hepta-CDF 0,28 0,01 0,0028 1.2.3.4.7.8.9- Hepta-CDF n.d. 0,01-1.2.3.4.6.7.8.9- Octa-CDF 1,92 0,0001 0,000192 1: multiplication with TEF 2: addition to TEQ WHO-TEQ 1,5 6
Exposure Pathways of Dioxins Emission Incineration Industry Chlorine Industry deposition Environment Rain/deposition Dump Sites/Sludge bioaccumulation Beef, cow milk/-products Pork/ -products Chicken/ -products Food Thermal Metal Process Plants, gras Fish/ -products Car Exhaust Soil / Water Humans Vegetables 95% 7
PCDD/F intake by humans Intake of PCDD/F Occupational Accidental Environmental (background) Food consumption 95% (mainly fat-containing food of animal origin) EU legislation on food Example: raw milk 2,5 pg TEQWHO05 / g fat Example: eggs 2,5 pg TEQWHO05 / g fat EU: daily intake at about 1 pg / kg b.w. * d Recommendations (e.g. WHO, SCF): ADI 2 pg / kg b.w. * d 8
Importance of Soil? Now, where is the influence of soil? Intake of PCDD/F via soil Direct route of exposure: Inhalation of air particulates Ingestion of contaminated soil Dermal absorption Indirect route of exposure: food Via plants Via animals (meat, milk, eggs) 9
SOIL Typical and elevated PCDD/F concentrations 10
Soil, PCDD/F background values and influence of use / origin, Germany Soil Type n German Regions ("Länder") averaged concentration means (ng I-TEQ/kg) averaged 90% percentiles Farmland 498 1,5 3 Grassland 260 3,4 7,8 Forest, top layer 70 10,8 41,5 Forest, soil 186 3,5 16,6 summarized, after LABO 2003 *) Soil Type n Bavaria Concentration median (ng BGA-TEQ/kg) maximum Farmland 41 0,24 ND -18 Grassland 27 0,6 ND - 18 Forest, top layer 32 10 ND - 50 Forest, soil 30 0,8 ND - 17 Green spaces 30 1 ND - 13 Fiedler 1998 *) «Bund/Länder-Arbeitsgemeinschaft Bodenschutz» (LABO) 2003 (collection of all available, partially older, data) https://www.labo-deutschland.de/documents/hintergrundwerte_anhang_a79.pdf
TEQ (PCDD/PCDF only) in Sediment and Soils from EU Member States, ng /kg d. m. Sediment Soil Background, Urban Any Type, Pasture, Rural Austria 1.6-14 Belgium 2.7-8.9 Finland 0.7-100 Germany 1.2-73 0.1-42 Greece 2-45 Ireland 0.2-13 Italy 0.1-23 0.1-43 Luxembourg 2.4-16 1.4-20 Netherlands 1-10 2-55 Spain 0.1-8.4 Sweden 0.8-207 0.1 U. Kingdom 2-123 0.8-87 Fiedler et al., 1999 12
Examples for elevated soil levels Values in TEQ, pg/g Taiwan PCP Production some 1,000,000 Vietnam Agent Orange *) about 1,000,000 Seveso TCP Production some 100,000 **) Germany Herbicide Production some 100,000 USA Horse Arena some 100,000 Germany Metal Reclamation some 10,000 Japan MWI vicinity some 1,000 UK Fly ash pathways some 1,000 *) Former air base **) values given in g/m2 13
SOIL Legislation 14
Soil guideline concentrations (TEQ, ng/kg d.m.) Germany (recommendations BLAG 1992; BBodSchV 1999) < 5 Target concentration for agricultural use and decontamination 5 40 limited agricultural use (plants, grazing limited) > 40 research on origin; no agricultural use > 100 measures to be taken on children playgrounds > 1000 measures to be taken in residential areas > 10,000 measures to be taken independent of the location The Netherlands 1 Agricultural farming 10 Dairy farming Sweden 10 Sensitive uses 250 Non-sensitive uses Japan 1000 15
SOIL-HUMAN: direct intake 16
Direct Intake: Ingestion of soil Soil ingestion in children and adults of the same family Children: 37 207 mg/day Adults: 23 625 mg/day (Davis et al., 2005; based on titanium as tracer) 0,14 0,12 0,1 Daily Intake (g/day) 0,08 0,06 0,04 0,02 0 0 to 1 1 to 2 2 to 3 3 to 4 4 to 5 5 to 6 6 to 7 Age group (years) www.epa.gov/superfund/lead/products/ssircolo.pdf 17
Ingestion of soil by humans - calculation Assumption: Soil intake 0.1 g/d Soil contamination 10 ng TEQ / kg (elevated background) Body weights: toddler 12 kg; adult 70 kg Resulting intake: 1 pg TEQ / day = 0.083 pg / kg BW * d for toddlers = 0.014 pg / kg BW * d for adults Limited relevance regarding livelong ADI of 2 pg TEQ/kg body weight*d Regulation Germany: soil exchange on >100 ng TEQ / kg = 0.83 pg / kg BW * d for toddlers??? 18
SOIL-HUMAN: indirect intake via food 19
Indirect intake SOIL-PLANT-FOOD Plants 20
Comparison of Dioxin Concentrations (ng TEQ / kg d.m.) in Food Plants, Corresponding Soil (0-25 cm) and Deposition (TEQ, m 2 /d) Lettuce Endive Kale Soil Deposition 2.4 28.5 65.6 75.1 56 1.5 5.6 20.8 77.6 20 3.1 14.4 53.7 35.9 51 2.8 5.5 20.3 16.4 21 1.8 2.2 4.0 21.3 7.4 2.2 1.7 2.6 21.8 5.7 MURL, 1995 21
Increase of PCDD/PCDF in Carrots depending of Soil Concentration Field Investigation Marsberg Krause et al., 1993 22
Transfer factors soil green plants Hembrock-Heger, 2011 23
SOIL-ANIMAL-FOOD flooding areas 24
Effects of Flooding on PCDD/F: River systems UK 1998/99 Grazing of milk producing cows on contaminated pastures resulted in contaminated milk. Samples were taken from farms with floodplain pastures and nearby control farms. Milk from flooded prone location: significant higher PCDD/F values for dioxins than from control sites. Food Standard Agency, UK, 1998f.; Dowding et al. 2006 25
SOIL-ANIMAL-FOOD Ingestion of soil by animals and biological availability of PCDD/F 26
Uptake of Soil by Grazing Animals, Overview Animal Uptake Reference Cow 6-14% of d. m. Healey, 1968 Cow 1.2-18.6 % of d.m. Mayland et al., 1975 Cow 1-18 % of d.m. Thornton & Abrahams, 1983 Cow 1-2 % of d.m. Berende, 1990 Sheep 0.4-14 % of d.m. Field & Purves, 1964 Sheep 75 kg/animal and year McGrath et al., 1982 Sheep 8% EFSA 2011 Sheep max. 30 % of d.m. Smith et al. 2009 Cow, Pig max. 20 % of d.m. Edwards,2003; Gummow et al., 2006 Pig 1.2-5.7 % of d.m. Fries et al. 1982 Chicken* max. 50 % of d.m. Serpe 2013 * free ranged 27
Soil ingestion by animals alongside feed intake - Difficult to estimate! - Different methods - Animal group (e.g. ruminants, poultry) and species dependency - General climate and latitude dependency - Local/regional climate dependency - Season dependency - Pasture abundance and quality - Density of grazing animals - median: 6%; maxima up to 50%! (G. Brambilla, Chemosphere 2014, in press; EFSA 2011) 28
Dioxins on Soil: bioavailability PCDD/F bound to soil are Not as bioavailable to animals as feeding stuff, where PCDD/F are dissolved in fat Relative to feeding stuff available to about 40% for TCDD Partially less bioavailable (fly ash 30%, soil down to 20%) (Fries 1987, 1990) 29
SOIL-ANIMAL-FOOD Calculation of soil contribution using the buffalo milk incident, Italy 2008 30
Italy, Campania region Buffalo raising in farms For milk production Original Mozzarella cheese from Buffalo milk Illegal waste burning Open fires PCDD/F formation Air transport of PCDD/F and PCB to feed growing, grazing and living areas Analytical program Buffalo milk Cow milk, sheep milk Animal feed (simple, compound) Soil picture: Wikipedia, modified 31
PCDD/F data PCDD/F-TEQ (WHO1998), incl. buffalo milk cow milk sheep milk basic feed other feed soil n = 732 57 20 162 56 164 pg/g fat pg/g fat pg/g fat ng/kg 12% w.w. ng/kg 12% w.w. ng/kg dry average 2,89 1,80 4,25 1,06 0,17 1,49 median 1,41 1,07 2,79 0,17 0,10 1,05 s.d. 5,22 1,73 4,20 4,97 0,17 1,61 min 0,21 0,39 0,28 0,05 0,05 0,89 max 87,00 8,98 12,90 60,40 0,76 12,80 5%-quantile 0,37 0,53 0,29 0,06 0,06 0,92 95%-quantile 8,64 4,81 11,10 2,80 0,53 3,20 EU action limit (*) 2 2 2 0,5 0,5 n/a % samples above EU action levels 38,8% 22,8% 55,0% 22,0% 9,8% n/a EU maximum limit (*) 3 3 3 0,75 0,75 n/a % samples above EU maximum limit 26,6% 17,5% 50,0% 18,3% 1,6% n/a (*) food: action levels/maximum levels; feeding stuff: action threshold/maximum contents, for feeding stuff compared to limits for "plant origin" and "compound" since details are partially unknown (Neugebauer, 2009) 32
From soil to milk: conditions for example calculation - Feed consumption per day: 16 kg, e.g. grass - Adhering soil: 6 % (conservative) = 0,96 kg - Bioavailability in soil 40% (TetraCDD) - Milk production: 8 kg / d - Milk fat content: 8,5 % Soil, assumed pattern - Carry over rates (COR): Literature average / Brambilla 2008 2378 TetraCDF 0,595 12378 PentaCDF 0,66 23478 PentaCDF 0,87 123478 HexaCDF 0,58 123678 HexaCDF 0,72 123789 HexaCDF 0,68 234678 HexaCDF 0,58 1234678 HeptaCDF 1,545 1234789 HeptaCDF 0,765 OctaCDF 3,33 2378 TetraCDD 0,26 12378 PentaCDD 0,385 123478 HexaCDD 0,76 123678 HexaCDD 0,7 123789 HexaCDD 0,62 1234678 HeptaCDD 2,485 OctaCDD 12,35 WHO(2005) PCDD/F TEQ excl. LOQ 0,1855 WHO(2005) PCDD/F TEQ incl. LOQ 0,963 33
From soil to milk: Example calculation Calculation examples: TEQ-Values (WHOTEF05) soil milk transfer ng TEQ/kg soil ng TEQ/d available carryover: COR (cow) ng TEQ/d ng TEQ/kg milk ng TEQ/kg fat factor milk:soil median soil Naples 0,96 0,37 Brambilla 08 0,17 0,02 0,26 0,27 10 ng TEQ/kg soil Naples 9,47 3,64 Brambilla08 1,63 0,20 2,40 0,25 + COR: average literature 9,47 3,64 average COR 0,83 0,10 1,22 0,13 + soil intake: 20% 9,47 12,12 Brambilla08 5,45 0,68 8,01 0,85 + soil 20% / 6kg/d / 7,5% fat 9,47 12,12 Brambilla08 5,45 0,91 12,11 1,28 other pattern: Bien Hoa 1182385 1513453 Brambilla08 844036 105505 1241230 1 34
From soil to milk: details of calculation for one scenario calculation soil milk 10 ng/kg ITEQ TEF TEF WHOTEF 05 COR cow (Brambilla 2008) WHOTEF WHOTEF ng TEQ/kg ng TEQ/d ng TEQ/kg ng TEQ/kg ng/kg soil 05 05 soil available ng TEQ/d milk fat 2378-TetraCDF 5,00 0,1 0,1 0,4999 0,6399 0,028 0,0182 0,0023 0,027 12378-PentaCDF 4,41 0,03 0,03 0,1323 0,1693 0,049 0,0083 0,0010 0,012 23478-PentaCDF 5,98 0,3 0,3 1,7945 2,2969 0,631 1,4503 0,1813 2,133 123478-HexaCDF 8,43 0,1 0,1 0,8435 1,0797 0,467 0,5044 0,0631 0,742 123678-HexaCDF 6,23 0,1 0,1 0,6226 0,7970 0,460 0,3664 0,0458 0,539 123789-HexaCDF 1,86 0,1 0,1 0,1864 0,2386 0,125 0,0299 0,0037 0,044 234678-HexaCDF 9,44 0,1 0,1 0,9442 1,2085 0,407 0,4917 0,0615 0,723 1234678-HeptaCDF 40,16 0,01 0,01 0,4016 0,5141 0,107 0,0550 0,0069 0,081 1234789-HeptaCDF 4,70 0,01 0,01 0,0470 0,0601 0,135 0,0081 0,0010 0,012 OctaCDF 49,17 0,0003 0,0003 0,0148 0,0189 0,020 0,0004 0,0000 0,001 2378-TetraCDD 0,76 1 1 0,7557 0,9673 0,562 0,5438 0,0680 0,800 12378-PentaCDD 1,79 1 1 1,7934 2,2955 0,597 1,3702 0,1713 2,015 123478-HexaCDD 3,41 0,1 0,1 0,3407 0,4361 0,416 0,1812 0,0226 0,266 123678-HexaCDD 3,71 0,1 0,1 0,3708 0,4746 0,520 0,2468 0,0309 0,363 123789-HexaCDD 3,27 0,1 0,1 0,3266 0,4181 0,293 0,1226 0,0153 0,180 1234678-HeptaCDD 35,30 0,01 0,01 0,3530 0,4518 0,113 0,0509 0,0064 0,075 OctaCDD 150,93 0,0003 0,0003 0,0453 0,0580 0,014 0,0008 0,00010 0,0012 TEQ 9,47 9,47 12,12 Brambilla08 5,45 0,68 8,01 Milk : Soil 0,85 35
Transfer of Dioxins by Consumption of Poultry and Products SOIL-ANIMAL-FOOD: poultry 36
Sources of Dioxins in Eggs: contribution of different origins Cage hens Feed 41 % 11 % 24 % Free range hens Feed Worms and insects Herbs, grasses, vegetables, leavings from kitchen gardens 24 % Food Worms Herbs Soil Soil G. Schoeters, R. Hoogenboom, 2006 37
Soil vs. PCDD/F in Eggs EU limit value eggs: 2.5 G. Schoeters, R. Hoogenboom, 2006 38
Discussion and conclusions 39
Take Home The contamination of soil DOES contribute sometimes significantly to the overall dioxin burden of humans This burden is especially important for producing meat or food, especially by raising and nourishing animals Care has to be taken especially for single cases due to high variability in contributingfactors Environmental legislation and feed/food legislation will have to merge further in order to consider the whole picture
Thank you for your attention!