Exposure uncertainty

Racoon dog (Sergey Gaschak, Chornobyl Center)

Wildlife camera in the CEZ

Wolf (Sergey Gaschak, Chornobyl Center)

Assessing the uncertainty of exposure of wildlife under field conditions

The current approaches used to estimate the exposure of wildlife to ionising radiation have been criticised as being too simplistic because they do not consider how animals utilise their environment. The ‘state-of-the-art’ is typically to average the available measurements of media concentrations or, at best, to use geographical information systems to estimate an average concentration within a typical home range for a given species. There is little evidence to support or counter the criticisms or to evaluate uncertainties associated with existing methodologies. Whilst there have been a number of international model-data comparisons, few studies have attempted to measure the exposure of wildlife to validate predictive exposure models. 

Hypotheses:

Current simplistic assumptions which ignore how animals utilise their environment ensure wildlife is protected by generating a conservative estimate of exposure

Wildlife camera traps

Working with our Ukrainian collaborators (Chornobyl Center), we have deployed 42 wildlife trap cameras within the Chernobyl exclusion zone (CEZ) (see initial camera sites being established). The outputs of these will be used to help us identify our study species and trapping sites. Currently we envisage that the species we trap for the studies described below will be either European grey wolf (Canis lupus lupus) or raccoon dog (Nyctereutes procyonoides).

We will also be able to use the cameras to make population estimates thereby providing a useful input to the debate on the impact of ionising radiation on wildlife in the CEZ.

CLICK HERE to view a selection of photographs from the trap cameras.

Estimating the exposure of wild mammals

We will evaluate pathways of exposure for large mammals (e.g. racoon dog, wolf) by trapping individuals and fitting each individual with a collar containing a thermoluminescent dosimeters (TLD) (in collaboration with Public Health England), a GPS tracker and a radio-tag. We will also fit our GPS collars with a modified version of the Instadose 2 dosimeter which MIRION Technologies have kindly agreed to adapt and supply. The TLDs will provide an integrated measurement of radiation exposure over the entire study and the Instadose 2 will give multiple daily exposure measurements.

We are studying mammals due to their relatively large home ranges. The CEZ is an ideal study site as it has high levels of contamination and soil activity concentrations are spatially heterogeneous. Animals will be tracked for one year.

The resultant data will enable us to determine the actual external dose rate received and compare this to the dose predicted using: (i) ‘the traditional approaches’ of assuming home ranges around the point of capture; (ii) spatial behaviour models.

Faecal DNA

We will quantify internal exposure of these animals using a combination of faecal DNA analysis and live-monitoring.  A recently developed DNA metabarcoding approach allows determination of dietary composition through faecal analysis.  This state of the art methodology is being used to evaluate uncertainties in the estimation of internal exposure resulting from diet selection. We are supplementing the faecal DNA-informed evaluation of internal exposure with live-monitoring of the animals at the start and end of the exposure assessment.The University of Comte (France), who have contributed to the development of faecal DNA bar coding to estimate dietary composition, will be collaborating in this aspect of our work.

Bank vole fitted with TLD

Cs deposition in the CEZ (Chornobyl Center)

Inspecting wolf faeces in the CEZ

We will provide an evaluation of the extent to which current simplistic and pragmatic exposure assumptions ensure that wildlife are protected.

For further information contact: Dr. Mike Wood (University of Salford)