Polonium-210 in Freshwater Environments: Analytical Advances, Predictive Modelling, Food Web Transfer and Dose Assessment
type: CreativeWork
description: Polonium-210 (²¹⁰Po) is a naturally occurring radionuclide of high radiological relevance, yet its occurrence, environmental behaviour and biological transfer in freshwater ecosystems remain poorly characterized. Advances in understanding have been constrained by analytical challenges and by radiation protection frameworks that historically emphasized human health, with ecological risks only more recently being addressed. This thesis addresses these knowledge gaps by validating a rapid, highly sensitive method for measuring ²¹⁰Po, and its parent radionuclide lead-210 (²¹⁰Pb), in diverse environmental matrices and applying this method to conduct the most spatially extensive survey of ²¹⁰Po and ²¹⁰Pb in Canadian freshwater systems to date. The optimized copper sulphide (CuS) micro-precipitation method achieved high chemical recoveries (>90%), low detection limits (~ 0.01 mBq·L⁻¹), and high sample throughput. Its sensitivity and efficiency enabled the development of a comprehensive database of ²¹⁰Po and ²¹⁰Pb activity concentrations across 31 freshwater systems, spanning abiotic compartments and food webs. Complementary non-radiological data were also collected, and integrated statistical and machine-leading analyses identified dissolved organic carbon, dissolved uranium and calcium as key predictors of ²¹⁰Po activity concentrations in surface waters, with predictive accuracies up to 76%. These results highlight the roles of local geology and water chemistry in driving radionuclide mobility and suggest that climate driven processes such as permafrost thaw and lake browning may further influence ²¹⁰Po behaviour in freshwaters. A strong radiological association between ²¹⁰Po and ²¹⁰Pb was also confirmed for the abiotic compartments. Food web analyses revealed that water chemistry, particularly electrical conductivity and dissolved uranium, significantly influenced biological uptake. Trophic magnification factors demonstrated clear biomagnification of ²¹⁰Po and trophic di…
abstract: Polonium-210 (²¹⁰Po) is a naturally occurring radionuclide of high radiological relevance, yet its occurrence, environmental behaviour and biological transfer in freshwater ecosystems remain poorly characterized. Advances in understanding have been constrained by analytical challenges and by radiation protection frameworks that historically emphasized human health, with ecological risks only more recently being addressed. This thesis addresses these knowledge gaps by validating a rapid, highly sensitive method for measuring ²¹⁰Po, and its parent radionuclide lead-210 (²¹⁰Pb), in diverse environmental matrices and applying this method to conduct the most spatially extensive survey of ²¹⁰Po and ²¹⁰Pb in Canadian freshwater systems to date. The optimized copper sulphide (CuS) micro-precipitation method achieved high chemical recoveries (>90%), low detection limits (~ 0.01 mBq·L⁻¹), and high sample throughput. Its sensitivity and efficiency enabled the development of a comprehensive database of ²¹⁰Po and ²¹⁰Pb activity concentrations across 31 freshwater systems, spanning abiotic compartments and food webs. Complementary non-radiological data were also collected, and integrated statistical and machine-leading analyses identified dissolved organic carbon, dissolved uranium and calcium as key predictors of ²¹⁰Po activity concentrations in surface waters, with predictive accuracies up to 76%. These results highlight the roles of local geology and water chemistry in driving radionuclide mobility and suggest that climate driven processes such as permafrost thaw and lake browning may further influence ²¹⁰Po behaviour in freshwaters. A strong radiological association between ²¹⁰Po and ²¹⁰Pb was also confirmed for the abiotic compartments. Food web analyses revealed that water chemistry, particularly electrical conductivity and dissolved uranium, significantly influenced biological uptake. Trophic magnification factors demonstrated clear biomagnification of ²¹⁰Po and trophic di…
author: Walsh, Stephanie
language: en
keywords: Naturally Occuring Radioactive Material, Polonium-210, Lead-210, Predictive Modelling, Fate and Transport, Food Web Transfer, Transfer Parameters, Internal Dose, Radioecology, Risk Assessment, Bioaccumulation Factors, Trophic Magnification Factors
date published: 2026-04-01T16:24:19Z
date modified: 2026-07-24T03:39:42Z
provider: University of Ottawa
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Université d'Ottawa / University of Ottawa

PropertyValue
property ID: Handle
value: http://hdl.handle.net/10393/51496

PropertyValue
property ID: DOI
value: 10.20381/ruor-31829