Radionuklider og spormetaller i mat

Transkript

1

2 DNVA november 2014 Radionuklider og spormetaller i mat Brit Salbu, CERAD SFF/NMBU

3 Brit Salbu, CERAD, CERAD CoE to meet challenges in radioecology: To provide new scientific knowledge and tools for better protection of humans and the environment from harmful effects of radiation Essence: To significantly reduce the overall uncertainties in impact and risk assessments associated with radiation (ionizing + UV), also combined with other stressors Focus: sources, ecosystem transfer, biological effects, and on impact/risk for man and the environment, economy and society Vision - scientific output: Novelties/ major progress at the interface between disciplines New concepts: integrated concept for man and the environment, integrated concept for contaminants, integrated concept ionizing and UV, effect unit non-human organisms Cutting edge: combination of advanced tools from other disciplines Dynamic models: time and climate depended variables From sources to risks Ionising radiation +? DNA Damage Partners: NMBU, NRPA, MET, NIVA, NIPH Funded for 10 years by the Research Council of Norway Network: 10 scientists from the international community

4 We are exposed to a series of radionuclides and trace metals from natural and man-made sources Natural sources: Cosmic and terrestrial derived uranium Regulations and daughters Radiation Protection of Man and the Environment, 2000 Pollution Control Act 2011 Forskrift av 27. september 2002 om visse forurensende Anthropogenic stoffer i næringsmidler Radioactivity (Lovdata) sources: releases from Fôrvareforskriften the nuclear cycle Man made Gjødselvareforskriften production Internasjonale of avtaler (Hg)/Codex All. contaminants Gamma plutonium, americium Releases of radionuclides followed by dry and wet depositions, ecosystem transfer Cosmic radiation Medicines Inhalation, skin Brit Salbu, deposition, UMB intake of food, water: organics, metals, radionuclides

5 Challenges in radioecology: Linking radionuclide species in releases from sources to impact and risk assessment Sources Sources Sources Key Food Chains Transport in different ecosystems Inhalation - animals - food products Climate Processes in soil / water / sediments Pathogens/virus conditions Deposition/soil - plant uptake - domestic animals - milk and meat cow, sheep, goat Deposition - lichens - reindeer - meat Deposition plants translocation grazing membrane animals Bioavailability Deposition run-off Exposure fresh water fish Biological Uptake/effect Effluent/releases oil and gas industry - marine fish/bentic Impact/risks

6 Kilder mat i Norge: Naturlige og menneskeskapte kilder lokalt/regionalt/internasjonalt Naturlig: geologi/mineralogi/jordkjemi/ph/geografi-sjøsalt Radionuklider Atmosfæriske prøvesprengninger ( årene) Atomulykker: Chernobyl 1986 Antropogen NORM: NORM: Olje og gass industri Gruvedrift Treforedling Uranholdige bergarter/mineraler: Alunskifer, svartskifer, granitter Har områder med gammadoser blant de høyeste i Europa NORM: U Ra-226, Po-210, Pb-210 Metaller Metallurgisk industriutslipp Forbrenning fossilt brensel, særlig kull (Hg, As, Cr, Se) Forbrenning avfall (Hg, Cd, As,Zn) Kunstgjødsel (Cd) - landbrukspraksis Antropogen anrikning koeffisient (AEF) Cd 89 % Pb 97 % - Pb bensin Hg 66 % En rekke bergarter/mineraler/jordarter inkl alunskifer og svartskifer - landbrukspraksis 6

7 Brit Salbu, Isotope Laboratory, Case: Nuclear weapons tests in the atmosphere and underground (UNSCEAR, 2000) October 30, 1961

8 Case: Atmospheric Nuclear Weapons Tests Key radionuclide of concern: I-137: milk and milk products (short lived) Cs-137, T1/2 30 yrs (K analogue). Reindeer, mushroom, sheep, goat Sr-90, T1/2 28 yrs (Ca- analogue) Estimated ground deposition of Cs- 137 from nuclearweapon fallout, decay converted for Depositions followed rain fall - Particle deposition observed in air filters Fallout in Norway: NS - gradient EW - gradient

9 How to identify a source? Air filters collected in Norway in October 1962 (Wendel et al, 2013). Autoradiography images hot particles Pu and U isotope ratios - AMS Ve mbq m -3 V mbq m -3 B mbq m -3 Ro mbq m -3 B mbq m -3 Å mbq m -3 Bo mbq m -3 Ro mbq m -3

10 Source identification: Pu and U atom ratios in particles (AMS) 241 Pu/ 239 Pu activity ratio 10,00 1,00 0,10 Palomares Tel kem 1 particles Global weapons fallout (Kelley et al., 1999) Thule partices Ground Zero, Semipalatinsk ( Thule, Greenland Kyshtym, Mayak PA, Russia Weapon grade Chernobyl particles (n=6) Dounreay Material Testing Reactor Global Fallout (Kelley et al., 1999) Civil source Yenisey particles, downstream Krasnoyarsk 0,01 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0, Pu/ 239 Pu atom ratio

11 Looking for the releasing source: Pu isotope ratio, air transport 2 potential sources: Novaya Zemlya or STS????? Source identification of Pu and 236U deposited on 11

12 Source identification of Pu and 236U deposited on 12

13 Source identification of Pu and 236U deposited on 13

14 Source identification of Pu and 236U deposited on 14

15 Source identification of Pu and 236U deposited on 15

16 Source identification of Pu and 236U deposited on 16

17 Source identification of Pu and 236U deposited on 17

18 Source identification of Pu and 236U deposited on 18

19 19

20 20

21 21

22 22

23 23

24 24

25 25

26 26

27 27

28 28

29 29

30 30

31 31

32 32

33 33

34 34

35 35

36 36

37 37

38 38

39 39

40 40

41 41

42 42

43 s 43

44 44

45 45

46 46

47 47

48 48

49 49

50 50

51 51

52 52

53 53

54 54

55 55

56 56

57 57

58 58

59 59

60 60

61 61

62 62

63 63

64 64

65 65

66 66

67 67

68 68

69 69

70 70

71 71

72 72

73 73

74 74

75 75

76 76

77 77

78 78

79 79

80 80

81 81

82 82

83 83

84 84

85 85

86 86

87 87

88 88

89 89

90 90

91 91

92 92

93 93

94 94

95 95

96 96

97 97

98 98

99 99

100 100

101 101

102 102

103 103

104 104

105 105

106 106

107 107

108 108

109 109

110 110

111 111

112 112

113 113

114

115 Case Chernobyl accident: Deposition in Scandinavia 1986 Max: 100 kbq/m 2 Mean: 7 kbq/m 2 Particle deposition Countermeasures still needed

116 137 Cs Concentrations in Reindeer: Vågå district

117 Wholebody Measurements of Cs-137 Whole body concentration of 137 Cs (Bq kg -1 ) Northern Norway, men Northern Norway, women Central Norway, men Central Norway, women Max Cs-134+Cs-137 (1988) ~1 msv/year Year

118 Milk without and with Cs-binder as measures 2014 Still problem: every year enriched in mushroom

119 Case: NORM Th resources In door Rn Alum shale area Alunskifer en rekke tungmetaller s inneholder om kadmium, kobber, nikkel, sink, kvikksølv samt arsen. Sulfid - svovelsyren bidrar til mobilisering av tungmetallene fra alunskifer til avrenningsvannet. Alunskifer inneholde opptil 170 mg/kg av uran, hvor urandøtrene er de største dosebidragsytere vi kjenner NRPA, 2000 / 2001

120 Case: Concentration of trace elements and U in alun shale soils, mg/kg d.w. - Stikkprøver Prøve Cr Co Ni Cu Zn As Cd Ba Pb U Ec1 45 ± 2 10 ± 0,4 55 ± 1 48 ± ± 6 20 ± 0,5 1,8 ± 0, ± ± 0,5 14 ± 0,6 Ec1 løk 51 ± 1 13 ± 1 64 ± 3 48 ± ± 4 19 ± 1 1,8 ± 0, ± ± 0,4 16 ± 0,4 ØEc1 potet 56 ± 1 14 ± 0,2 86 ± 1 57 ± ± 3 20 ± 1 2,0 ± 0, ± ± 0,5 48 ± 2 Conv 42 ± 3 12 ± 1 42 ± 1 36 ± ± 6 13 ± 1 1,3 ± 0, ± ± 0,6 6,3 ± 0,2 Ec2 66 ± 3 17 ± ± 5 90 ± ± 5 53 ± 2 3,5 ± 0, ± ± 0,7 31 ± 1 Act. cons of Po-210 in soil, Bq/kg Brit Salbu, CERAD, Prøve 210 Po (Bq/kg) Øk1 725 Øk1 potet 883 Øk1 løk 627 Øk Konv 989 Man-made radioactive waste: U=1 Bq/g -factor about 50 P0-210 = 1Bq/g factor 2

121 Transfer of trace elements and U from soil to vegetables (mg/kg d.w. vegetables/mg/kg d.w. soil, or Bq/kg vegetables/bq/kg soil) Ra-226 CF 2 x10-2 carrot, 1 for wheat (ORNL, 1983) Mangler data fra Norge Farm As Cd Ba Pb Ni Cu U Cauliflower Ec1 Conv 3,1* ,15 0,04 0,01 0, ,3*10-3 0,02 0,02 0,05 0, Carrot Ec2 5,1*10-4 0,21 0,06 7,5*10-4 0,02 0, Onion Ec1 Conv Øk2 Potato Ec1 -large Ec1-small Ec2 -small 6,7*10-4 8,3*10-4 1,0*10-3 5,3*10-4 1,2*10-4 2,1*10-4 0,08 0,11 0,09 0,04 0,05 0,04 0,04 0,01 0,02 2,7*10-3 8,0*10-3 1,1* ,7* ,3*10-4 0,02 8,3*10-3 8,9*10-3 3,5*10-3 5,6*10-3 3,3*10-3 0,03 0,08 0,04 0,13 0,06 0,10 Lattuce Ec1 1,8*10-3 0,28 0,02 2,0*10-3 0,02 0, ,8*

122 Doses to man Natural sources: more than 50 % Doser stedvis langt høyere enn tillatt grense (1 msv/år) National Council on Radiation Protection and Measurements

123 Case: Hg from industry etc. today Siegel & Siegel 1997, i Bjerregaard

124 Hg in lake sediments Reduced acidity, increased TOC, increased Hg in lakes After: Rognerud 2004

125 DEPOSITION COMPLEX SYSTEM DEPOSITION VOLATILISATION AND DEPOSITION VOLATILISATION AND DEPOSITION Hg(II) DEPOSITION AND RUNOFF REDUCTION Hg(0) DEMETHYLATION CH 3Hg DEPOSITION AND RUNOFF Hg(II) OUTFLOW CH Hg 3 OUTFLOW METHYLATION OUTFLOW SEDIMENTATION BIOMAGNIFICATION DIFFUSION/ SEDIMENT RESUSPENSION SEDIMENTATION Hg(II) CH Hg 3 FMI : Organo-metals. Bjørn Olav Rosseland 125

126 126

127 US-EPA 1999 New consumers advice for Hg US-EPA 2001 UN-FAO/WHO 2011 Consumer advice Trade limitation Norway 127

128 Kostholdsråd SFT/SNT Ferskvanns-kannibal fisk Statens næringsmiddeltilsyn har innført: Landsomfattende kostholdsråd for ferskvannsfisk, på bakgrunn av kvikksølvmålinger. Kostholdsrådene gjelder gjedde, abbor over 25 cm, og stor ørret og røye(over 1 kilo). Råd til gravide Gravide og ammende bør unngå å spisedisse fiskeslagene. Andre bør ikke spise slik fisk mer enn en gang i måneden. Selenium protective agent against Hg toxicity. Hg-Se compounds increases excretion Norway low in Se Tittel på presentasjon 128

129 Concepts Regulation - Grenseverdier Radioaktivitet ALARA prinsippet as low as resonable achievable, taking economic and social aspects into account Linear dose-effekt relasjon Risiko for kreft i mennesker pga langtidseksponering; 30, 50 år eller levetid Tiltaksgrense - 1 msv/år (dose) akseptert dose og risiko Melk og barnemat: 370 Bq/kg Tamrein, vilt og vill ferskvannsfisk: 3000 Bq/kg Andre matvarer: 600 Bq/ kg Grenser Rad avfall U:1 Bq/g alunskifer jord Ved ny ulykke grenseverdier for Metaller Grenseverdier er i stor grad basert på: toxtester med ulike testorganismer og ekstrapolering til mennesker med estimerte «safety faktorer» epidemiologi. Få metaller i matvarer er regulert (Hg, Cd, Pb) Lovdata Cd: 0.05 mg/kg vv frukt og grønnsaker Unntak- økt grense for potet, gulrot, korn Pb: 0.10 mg/kg vv frukt og grønnsaker Unntak- økt grense for korn, kål, bær Økt grense for storkonsum varer! EU vil senke Cd grensen til 0.5 mg/kg

130 Many stressors induce free radicals in organisms Multiple Stressors: We are exposed to a cocktail of stressors Heavy metals Radionuclides Organics Bonding breaks DNA, RNA Free radicals Recombination Vi må også ta hensyn til «defence system»: essensielle spormetaller og antioksidanter når belasting av miljøgifter vurderes. Norge er et Se fattig land * cells die * cells are repaired * cells are wrongly repaired I dag reguleres ett stoff av gangen. H 2 O 2, O 2 Oxidising cell membranes Vi blir utsatt for stoffer i blanding som kan bidra til samvirkende effekter. Can simultaneously affect the same sensitive biological endpoints: Fremtidig mål: å regulere stoffer i blanding. additive, synergetic, antagonistic effects.

131 Take home message Det er mange kilder til metaller og radionuklider i mat Antropogene radionuklider under regulering og tiltak, basert på doser og akseptert risiko NORM alunskifer/svartskifer områder bidrar til de høyeste dosene. Reguleres kun om kilden er «man-made», tiltak Rn i hus. Hg kostholdsråd, vanskelig å iverksette tiltak Cd og Pb forhøyede nivåer i alunskiferområder. Bør vurdere produksjon og driftsformer Mangler grenseverdier for mange metaller/radionuklider Bør vurdering samvirkende effekter av blandinger Bør utvikle samme konsept for alle miljøgifter Nok å gjøre i tiden fremover

132 Spørsmål???

133 Thorium forekomster i Norge Oppdaget i 1828 av Berzelius I norske bergarter I på ett år - ble det utvunnet ca 2 tonn thorite fra mineraler ved Kragerø. NGU: Ingen Th prospektering foretatt i Norge. Th er vanskelig å utvinne. Kunnskap om Th ressurser I Norge er mangelfull og basert på gamle urandata (1950 og årene). Ressursene bør kartlegges Telemark Oslofeltet Vestfold Aust-Agder Nord-Trøndelag Nordland