Radioactivity and the Environment


Determining the biological effects of environmental radiations in laboratory and wild fish

Dr Adelaide Lerebours, Portsmouth University

  • The laboratory experiments consist in examining the effects of beta radiation (waterborne exposure to 32P) on early life stages of fish (embryo development, growth rate, hatching success and molecular pathway of stress).
  • Wild fish will be collected from lakes in Belarus and Ukraine forming a gradient of radiations (released from the Chernobyl Nuclear Power Plant catastrophe) and their health assessed using a range of biological tools (index conditions, genotoxicity assays, histological diagnosis and gene expression analyses).

TREE's Post Doctoral Research Associates introduce themselves ….. (TREE Newsletter 1, September 2014)

Improving our understanding and prediction capability for the long term biogeochemical behaviour of 129I, 79Se, 99Tc, and U isotopes, in soils

Dr Maria Izquierdo, University of Nottingham

The primary objective of this post-doctoral research project is to improve our understanding of, and ability to predict, the long term biogeochemical behaviour of 129I, 79Se, 99Tc, and U isotopes, in soils whilst assessing the validity of models parameterised from short-term laboratory experiments. In most soils 129I, 79Se,99Tc and U isotopes entering the biologically active zone, from precipitation/irrigation or groundwater sources and either undergo time-dependent transformation to relatively stable organic forms within humus (e.g. Se and Tc) or are occluded within poorly soluble oxides, phosphates and carbonates (e.g. U). The processes, and rate-determining factors, that control this 'transfer-to-sink' are poorly understood. For example, iodate (IO3-) is more strongly adsorbed by Fe/Mn oxides than iodide (I-) during transition to organic forms and must undergo reduction to a reactive species prior to interaction with humic C in contrast to the oxidation of iodide. Understanding the biogeochemical processes which control the behaviour of these radionuclides in soils will provide a strong platform on which to base defensible models of their future fate and impact which will be applicable to any repository site considered in the UK (or elsewhere). The project will address the key question of whether the long-term behaviour of 129I, 79Se, 99Tc and 235U in soils can be adequately predicted from an understanding of short-term biogeochemical dynamics. Thus, the hypothesis to be addressed is that the progressive equilibration of 129I, 79Se, 99Tc and U, in soil can be estimated from models parameterised solely from short-term isotopic mixing experiments. The current soil activity concentrations, geochemical fractionation and soil profile distributions of 235U, 99Tc and 129I in abandoned farmland and forest soils close to the Chernobyl NPP will be used to test that hypothesis.

TREE's Post Doctoral Research Associates introduce themselves ….. (TREE Newsletter 1, September 2014)

Phylogenetic and ionomic analyses to predict the plant uptake of radioactive contaminants

Dr Eleni Siasou, University of the West of England, Bristol

The main aim of the research is to improve the prediction of plant uptake of key radioisotopes (found in waste repositories i.e I-129, Tc-99, Se-79, U-235) using plant evolutionary history (phylogeny) and elemental composition (ionomics). Eleni is currently testing the uptake of the four radionuclides using phylogenetic informed sampling regime for flowering plants of the British flora and analysing the effect of their taxonomic relationships. She is also planning to work on meta-analyses of databases of the radionuclides transfer and look at the covariance of these four radionuclides with other radionuclides i.e Cs-137, Sr-90, and nutrients to provide a phylogenetic perspective on ionomic stoichiometry. This research intersects with TREE research on soils led by Nottingham University and on other organisms led by CEH Lancaster.

TREE's Post Doctoral Research Associates introduce themselves ….. (TREE Newsletter 1, September 2014)

Population Genetics in Drosophila

Craig Anderson, Stirling University

I'm a postdoc at the University of Stirling, focusing on the long-term impacts of ionising radiation upon populations of Drosophila melanogaster. My expertise lie in ecotoxicology and population genetics, including the use of RADseq for investigating population mapping, identifying candidate regions of the genome associated with adaptive traits and for genome assembly. Previously, I was an OCE postdoctoral fellow at CSIRO, investigating the adaptive capacity of the global pest, Helicoverpa armigera, and its impact upon the Americas following a recent invasion into Brazil. In order to better understand the genes associated with resistance, the gene flow between global populations, as well as the evolutionary history of the species complex, I made use of high-throughput sequencing and analytical techniques. I continue to contribute to this work through my role as a CSIRO affiliate. During my PhD, I was shared between CEH and Cardiff University, working to elucidate the effects of arsenic upon susceptible populations of the earthworm, Lumbricus rubellus. I incorporated a number of end points at different levels of biological complexity, ranging from life-history modelling to metabolomics, transcriptomic and chemical profiling in exposed individuals to provide a foundation for which to recognise resistance in natural populations.

More information (TREE website)