Effects of Radiation on Biota

Effects of Radiation on Biota
Radiological Protection of the Environment: CEH Lancaster November 2010 Effects of Radiation on Biota Tom Hinton (IRSN) CEH Lancaster 27th-29th June 2012 Effects

UK-CEH Risk Course; June 2012
Radiological Protection of the Environment: CEH Lancaster November 2010 OBJECTIVES To have a fundamental, introductory understanding of: radioactive decay and ionization as it relates to effects of radiation DNA’s role as the primary target for the induction of biological effects the broad similarities in radiation responses among organisms the wide variation in responses among organisms free radicals and their role in the biological effects from radiation repair of damage from radiation mis-repair of damage and the fate of mutations within a population of organisms fundamental differences in human versus ecological risk analyses from the perspective of radiation effects a general idea of the state of knowledge about radiation effects and some of the major data gaps that need to be addressed UK-CEH Risk Course; June 2012 Effects 2

Radiological Protection of the Environment: CEH Lancaster November 2010 Ionization The radiation emitted from radioactive atoms can be of sufficient energy to cause ionization of other atoms. Ionization occurs when energy is sufficient to eject an electron UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 DNA is the primary target for the induction of biological effects from radiation in ALL living organisms Broad similarities in radiation responses for different organisms……and yet, wide differences in radiation sensitivity UK-CEH Risk Course; June 2012 (Whicker and Schultz, 1982) Effects 4

Different kinds of DNA damage induced by γ-radiation per 0.01 Gy
Radiological Protection of the Environment: CEH Lancaster November 2010 Different kinds of DNA damage induced by γ-radiation per 0.01 Gy base loss base change H O OH H single stand break double stand break interstrand crosslinks Feinendegen, Pollycove. J. Nucl. Medicine V.42. p. 17N-27N UK-CEH Risk Course; June 2012 Effects 5

Free Radicals (unstable molecule that loses one of its electrons)
Radiological Protection of the Environment: CEH Lancaster November 2010 Free Radicals (unstable molecule that loses one of its electrons) UK-CEH Risk Course; June 2012 Effects 6

Radiological Protection of the Environment: CEH Lancaster November 2010 DNA damage and repair UK-CEH Risk Course; June 2012 Effects 7

Fate of Mutations Germ Cells Somatic Cells
Radiological Protection of the Environment: CEH Lancaster November 2010 Fate of Mutations Germ Cells Somatic Cells Decrease in number and quality of gametes Alteration to offspring Cell Death Cancer Increased embryo lethality UK-CEH Risk Course; June 2012 Effects 8

Fate of mutations in non-human biota
Radiological Protection of the Environment: CEH Lancaster November 2010 Fate of mutations in non-human biota For humans, risk of hereditary effects in offspring of exposed individuals is about 10% of the cancer risk to the exposed parents (UNSCEAR, 2001) For non-human biota the risk of hereditary effects is unknown Mutation Cell Confer a selective advantage Deleterious mutations Neutral mutations Spread in the population Remove from the population Persist over many generations UK-CEH Risk Course; June 2012 Effects 9

Radiological Protection of the Environment: CEH Lancaster November 2010 Knowledge of ionising radiation’s effect on wildlife is the basis for the derivation of radiological risk benchmarks UK-CEH Risk Course; June 2012 Effects 10

Data Base of Knowledge on Effects of Radiation Exposure on Biota
Radiological Protection of the Environment: CEH Lancaster November 2010 Data Base of Knowledge on Effects of Radiation Exposure on Biota FREDERICA ( An online database of literature data to help summarise dose-effect relationships FREDERICA can be used on its own; or in conjunction with the ERICA assessment tool (for conducting risk assessments of wildlife exposed to ionising radiation) (> 1500 references; data entries) UK-CEH Risk Course; June 2012 Effects 11

Radiation Effects on Non-Human Biota
Radiological Protection of the Environment: CEH Lancaster November 2010 Radiation Effects on Non-Human Biota Early Mortality premature death of organism These categories of radiation effects are similar to the endpoints that are often used for risk assessments of other environmental stressors, and are relevant to the needs of nature conservation and other forms of environmental protection Morbidity reduced physical well being including effects on growth and behavior Reproduction is thought to be a more sensitive effect than mortality Reproductive Success reduced fertility and fecundity UK-CEH Risk Course; June 2012 Effects 12

41 studies that included 28 species and 44 toxicants (Forbes & Calow, 1999) Population Growth Rate 52% Time to reach sexual maturity Mortality of juveniles No correlation 31% Reduction in number of offspring Mortality of adults UK-CEH Risk Course; June 2012

Fundamental Differences In Human and Ecological Risk Analyses
Radiological Protection of the Environment: CEH Lancaster November 2010 Fundamental Differences In Human and Ecological Risk Analyses Type Unit of Observation Endpoint Dose-Response Human individual lifetime cancer relationships risk established Ecological varies varies not established population, community, ecosystem > mortality, < fecundity, sublethal effects for chronic, low level exposure to radiation, alone, or mixed with other contaminants UK-CEH Risk Course; June 2012 Effects 14

Predicting radiological effects to wildlife is complicated because:
Radiological Protection of the Environment: CEH Lancaster November 2010 Predicting radiological effects to wildlife is complicated because: Populations are resilient Compensating mechanisms exist Blaylock (1969) studies at Oak Ridge DIRECT EFFECT: Increased mortality of fish embryos exposed to 4 mGy / d COMPENSATING MECHANISM: Fish produced larger brood sizes NET RESULT: No effect to population Indirect effects often occur that are unpredictable UK-CEH Risk Course; June 2012 Effects 15

Responses of Animals to Radiation Are Complicated by:
- other stresses (chemical, physical, biological) - life cycle stage and physiological condition - environmental variables Pika LD50 in captivity: ~ 5.6 Gy LD50 in the wild: ~ 3.8 Gy (Markham, et al. 1974) UK-CEH Risk Course; June 2012

Radiological Protection of the Environment: CEH Lancaster November 2010 CHERNOBYL 26 April 1986 Radioactive releases for 10 days Contaminated 200,000 km2 350,000 people relocated UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Wildlife Defies Chernobyl Radiation By Stephen Mulvey BBC News 20 April 2006 “It contains some of the most contaminated land in the world, yet it has become a haven for wildlife - a nature reserve in all but name”. Sergey Gaschak UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Chernobyl ‘Shows Insect Decline' By Victoria Gill, Science Reporter, BBC NEWS 18 March 2009 “Two decades after the explosion at the Chernobyl nuclear power plant, radiation is still causing a reduction in the numbers of insects and spiders”. A. Moller and T. Mousseau UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Pre-Chernobyl… wealth of data about the biological effects of radiation on plants and animals early data came from… laboratory exposures accidents (Kyshtym, 1957) areas of naturally high background nuclear weapons fallout large-scale field irradiators UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Before Chernobyl Chernobyl overview temporal aspects general effects to major classes of organisms indirect effects – confounding variables Possible reasons for controversy UK-CEH Risk Course; June 2012 Effects

Increasing Sensitivity Decreasing Sensitivity
Radiological Protection of the Environment: CEH Lancaster November 2010 Factors Influencing the Sensitivity of Plants to Radiation Increasing Sensitivity Decreasing Sensitivity Large nucleus Small nucleus Large chromosomes Small chromosomes Acrocentric chromosomes Metacentric chromosomes Low chromosome number High chromosome number Diploid or haploid High polypolid Sexual reproduction Asexual reproduction Long intermitotic time Short intermitotic time Long dormant period Short or no dormant period (Sparrow, 1961) UK-CEH Risk Course; June 2012 Effects

Lethal Acute Dose Ranges
Radiological Protection of the Environment: CEH Lancaster November 2010 Pre-Chernobyl… Lethal Acute Dose Ranges (Data from: Sparrow et al 1967) UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Pre-Chernobyl… Effects from Short Term Exposures (5 to 60 d) minor effects (chromosomal damage; changes in reproduction and physiology) intermediate effects (selective mortality of individuals within a population) UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 DOSE (Gy) to DOSE RATE (Gy / d) CONVERSION (5 to 60 d) Gy / d x/10 UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Within Chernobyl’s 30-km zone I II III Environmental effects were specific to 3 distinct time periods Biota were exposed to a diverse group of radioisotopes Tremendous heterogeneity and variability (in all parameters) Accident occurred at a period of peak sensitivity for many biota UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Dominated by short-lived isotopes 99Mo; 132Te/I; 133Xe; 131I; 140Ba/La First 20 to 30 days I Gamma exposure dose rates were > 20 Gy / d Severe effects to biota High dose to thyroids from iodine UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Air Exposure Rates on 26 April 1986 20 Gy /d 2 Gy /d 0.02 Gy /d 0.2 Gy /d (1 R / h ~ 0.2 Gy / d; UNSCEAR 2000) UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Dose rates from gamma exposures ranged from 0.02 to 20 Gy / d Gy / d UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 First Phase Acute adverse effects within 10-km zone Mortality to most sensitive plants and animals Reproductive impacts to many species of biota Gy / d UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Decay of short-lived isotopes Second Phase II Radionuclide migration β to δ ~ 6:1 to 30:1 with > 90 % of dose from β UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Third and Continuing Phase Dose rates are chronic, < 1% of initial Beta to gamma contributions more comparable, depends on bioaccumulation of Cs III 137Cs and 90Sr dominate dose Indirect effects dominate Genetic effects persist; although some results are controversial UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 General Effects to Plants Morphological mutations 1 to 15 Gy (e.g. leaf gigantism) Hardwoods more radioresistant Shift in ecosystem structure: Deceased pine stands were replaced by grasses, with a slow invasion of hardwoods Genetic effects extended in time 1993, pines of 5 to 15 Gy had 8 X greater cytogentic damage than controls Evidence of adaptive response UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Gy / d 0.3 Gy / d General Effects to Plants Growth and developmental problems Twisted needles Inhibition of photosynthesis, transpiration Chromosome aberrations in meristem cells Short term sterility High mutation rates in wheat due to non- targeted mechanisms UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 General Effects to Rodents During Fall 1986, rodents population < 2- to 10-fold, dose rates 1 to 30 Gy/d (δ & β) Gy / d At ~ 0.1 Gy/d temporary infertility, reduced testes mass Increased mortality of embryos Dose-rate dependent increase in reciprocal translocations Numbers of mice recovered within 3 years (immigration), but cytogenetic effects persisted UK-CEH Risk Course; June 2012 Effects

Effects Data from Rodents Collected in Phase III Are
Radiological Protection of the Environment: CEH Lancaster November 2010 Effects Data from Rodents Collected in Phase III Are Ambiguous and Controversial From virtually no effect…. … to significantly elevated mutation rates ~ 30 to 40 generations post-accident lower dose rates chronic exposures inadequate dosimetry sample size and technique sensitivity indirect effects (immigration) interpretation of results from new methods (microsatellites) III ~ 30 to 40 generations post-accident lower dose rates chronic exposures inadequate dosimetry sample size and technique sensitivity indirect effects (immigration) interpretation of results from new methods (microsatellites) UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 General Effects to Soil Invertebrates 60 to 90% of initial contamination captured by plant canopies Majority washed off to soil and litter within several weeks Populations of soil invertebrates reduced 30-fold, reproduction strongly impacted UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Dose and effects to invertebrates in forest litter were 3- to 10- fold higher than those in agricultural soils General Effects to Soil Invertebrates 30 Gy altered community structure (species diversity) for 2.5 years UK-CEH Risk Course; June 2012 Effects

Indirect Effects of Human Abandonment
Radiological Protection of the Environment: CEH Lancaster November 2010 Indirect Effects of Human Abandonment Pripyat Abandoned 4 km N of Reactor 50,000 people 135,000 people and 35,000 cattle evacuated Dozens of towns and villages deserted. UK-CEH Risk Course; June 2012 Effects

With the removal of humans, wildlife around Chernobyl are flourishing
Radiological Protection of the Environment: CEH Lancaster November 2010 With the removal of humans, wildlife around Chernobyl are flourishing 48 endangered species listed in the international Red Book of protected animals and plants are now thriving in the Chernobyl Exclusion Zone Russian Boar Wolves Przewalski Horses UK-CEH Risk Course; June 2012 Effects 40

A Natural History of Chernobyl
Radiological Protection of the Environment: CEH Lancaster November 2010 Wormwood Forest: A Natural History of Chernobyl Mary Mycio UK-CEH Risk Course; June 2012 Effects

Barn Swallows at Chernobyl
Radiological Protection of the Environment: CEH Lancaster November 2010 Barn Swallows at Chernobyl partial albinism as a phenotypic marker for mutations ( ↑ 10x) carotenoids used for free-radical scavenging…rather than plumage coloration reduced levels of antioxidants in blood increase in abnormal sperm elevated mutation rates in microsats partial albinism correlated to reduced mating success clutch size, brood size and hatching success reduced UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Gy / d IAEA Guidelines 1 & 10 mGy / d UK-CEH Risk Course; June 2012 PNEDR for ecosystems Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Potential Causes for Controversial Data Poor dosimetry can cause misinterpretation of data Spatial heterogeneity of exposure; free-ranging wildlife Confounding variables and indirect effects Lack of analogous controls Questionable statistical analyses What constitutes a “significant effect”?? Adaptation to generations of chronic exposure UK-CEH Risk Course; June 2012 Effects

Most research is not directly relevant to responses in nature
Radiological Protection of the Environment: CEH Lancaster November 2010 Most research is not directly relevant to responses in nature Data Plentiful but Least Relevant Data Scarce but Most Relevant Individual response Population response Mortality Reproduction Acute exposure Chronic exposure External gamma Multiple exposure route Laboratory Field Short-term Long-term UK-CEH Risk Course; June 2012 Effects

Radiological Protection of the Environment: CEH Lancaster November 2010 Questions remaining to be answered… What is the extent of inherited, transgenerational effects from chronic, low-level irradiation? What is the significance of molecular effects to individuals and populations? STAR Network of Excellence in Radioecology identified long term research needs in their Strategic Research Agenda ( UK-CEH Risk Course; June 2012 Effects

Effects from mixtures of contaminants…. Perfluoroctane Sulfonate (PFOS) UK-CEH Risk Course; June 2012

3M Company UK-CEH Risk Course; June 2012

760 random samples from across the U.S.
PFOS was in every sample 600 mores samples from the American Red Cross PFOS was in every sample 1500 samples from Belgium, the Netherlands and Germany PFOS was in every sample but two Alarmed, 3M notified EPA, and in 2000, 3M stopped production of PFOS UK-CEH Risk Course; June 2012

In the course of a single generation, we contaminated virtually all of earth’s biological systems with perfluoroctane sulfonate. UK-CEH Risk Course; June 2012

Metals Radiation Organics Focusing on a single type of stressor, or on multiple stressors in isolation from others, is likely inadequate to describe the actual threats to individuals or populations UK-CEH Risk Course; June 2012

Effects of Radiation on Biota

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