School of Physical and Chemical Sciences, Te Kura Matū Seminar Series

Travel Grant Recipient Talks - Rosemary Dorsey (Astronomy) and Sarah Guy (Environmental Sciences)


Rosemary Dorsey and Sarah Guy


School of Physical and Chemical Sciences

Time & Place

Fri, 13 Sep 2019 11:00:00 NZST in Room 701, Level 7, West Building

All are welcome


Rosemary Dorsey

Presenting ‘Modes of Oscillation of Variable Pulsating Stars Observed by TESS’ at the 2019 RASNZ Conference

Earlier this year I received a SPCS travel grant to attend the annual Royal Astronomical Society of New Zealand Conference, held in New Plymouth from the 17th – 19th of May. As a postgraduate student, I had the opportunity to represent the University of Canterbury by presenting the methodology for my Masters Thesis research project.

In this talk I outline the benefits of attending my first academic conference, summarise the presentation given at the conference, and report my research progress since May.


Sarah Guy

 How I used my travel grant?  Spatial variability of Polonium-210 in New Zealand shellfish and dose assessment

Recently, I received a travel grant from the SPCS to attend the SETAC (the Society of Environmental Toxicology and Chemistry) AU 2019 conference held in Darwin on 8-10th of July to present the results of my master research project: “Spatial variability of Polonium-210 in New Zealand shellfish and dose assessment”.

This presentation will focus on how attending the SETAC AU 2019 allowed me to progress with my research project. A short summary of the oral presentation given at the conference will also be presented.

Spatial variability of Polonium-210 in New Zealand shellfish and dose assessment

Exposure of the New Zealand population to radionuclides from ingestion originates mostly from naturally occurring radionuclides, with an appreciable contribution from 210Po through shellfish. Polonium-210 is a radionuclide from the decay chain of Uranium-238 with a half-life of 138.4 days. Naturally occurring processes and human activities can lead to the presence of 210Po in the marine environment and consequently in seafood.

Activity concentrations of 210Po in New Zealand shellfish were determined for 15 locations around the New Zealand coast over the period March 2018 to February 2019. Results ranged between 5 and 324 Significant spatial variability was observed with enhanced 210Po in two sampling sites located on the west coast of the Northland region. The source of enhanced 210Po is hypothesised to be increased uptake as a result of increased plankton concentration in water scavenging 210Po. Enhanced 210Po activity concentrations observed in the Northland region are of major interest as dose assessment showed that high seafood consumers in the affected areas are exposed to annual committed effective dose from 210Po in shellfish higher than 1mSv. However, results from the study are limited and do not allowed the identification of the origin of enhanced 210Po in shellfish with certainty.

Further work is proposed to determine the origin of the enhanced 210Po in shellfish.  Processes controlling 210Po bioaccumulation are complex and many factors are involved in controlling uptake behaviour. An uptake and depuration study is being planned to examine the effect of environmental condition on 210Po accumulation by shellfish and to model the behaviour of 210Po in shellfish. Finally, obtaining accurate shellfish consumption values for the population in affected areas is of major importance in order to accurately evaluate the exposure to ionising radiation. An accompanying diet survey collecting information on quantity, seasonal variation and type of shellfish consumed will be undertaken to evaluate exposure of the population to ionising radiation.

 All Welcome


Sarah Guy (ENVR) and Rosemary Dorsey (ASTR) are both postgraduate students in the School of Physical and Chemical Sciences