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Dive into the research topics where Mark Dowdall is active.

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Featured researches published by Mark Dowdall.


Science of The Total Environment | 2003

Gamma-emitting natural and anthropogenic radionuclides in the terrestrial environment of Kongsfjord, Svalbard

Mark Dowdall; Sebastian Gerland; B. Lind

This paper presents results obtained from a radiometric survey, conducted by the Norwegian Radiation Protection Authority, into the levels of gamma-emitting radionuclides, both anthropogenic and natural, in the terrestrial environment of Kongsfjorden, which lies on the North-Western Coast of Spitsbergen in the Arctic archipelago of Svalbard (79 degrees N, 12 degrees E). Samples of terrestrial matrices were taken during field campaigns conducted between 2000 and 2002 and analysed for a range of gamma-emitting radionuclides. The objectives of this study included an assessment of the levels of gamma-emitting radionuclides in the terrestrial environment of the region, identification of processes and activities that influence the accumulation and redistribution of such nuclides within the region and elucidation of the behaviour of such radionuclides within a high arctic environment. Results indicate a quite homogenous spatial distribution of such radionuclides within the study area and highlight the relatively low levels of contamination by the anthropogenic radionuclide, 137Cs, on Svalbard. Average values and ranges of the radionuclides activities in surface soils (0-3 cm) were: 238U 42 Bq/kg (17-134), 226Ra 43 Bq/kg (12-137), 232Th 21 Bq/kg (4-52), 40K 283 Bq/kg (31-564), 137Cs 35 Bq/kg (1-146). Average levels of these nuclides in avian faecal materials were 238U 63 Bq/kg, 226Ra 54 Bq/kg, 232Th 19 Bq/kg, 40K 365 Bq/kg, 137Cs 78 Bq/kg. Enrichment of radionuclides is apparent in soils taken from locations close to bird colonies in the locale, maximum levels of the radionuclides being found in samples associated with such colonies. The results indicate that this is due to concentration of such radionuclides within the faecal material of the birds and subsequent enrichment of the nearby soils either via direct incorporation of the faeces into the soil or by leaching processes. The results indicate that this process may result in contamination of non-related species, such as Svalbard reindeer (Rangifer tarandus playrhynchus), via pathways other than the traditionally accepted route of atmospheric deposition-vegetation-reindeer.


Journal of Environmental Radioactivity | 2008

Will global warming affect soil-to-plant transfer of radionuclides?

Mark Dowdall; W.J.F. Standring; G. Shaw; P. Strand

Recent assessments of global climate/environmental change are reaching a consensus that global climate change is occurring but there is significant uncertainty over the likely magnitude of this change and its impacts. There is little doubt that all aspects of the natural environment will be impacted to some degree. Soil-to-plant transfer of radionuclides has long been a significant topic in radioecology, both for the protection of humans and the environment from the effects of ionising radiation. Even after five decades of research considerable uncertainty exists as to the interplay of key environmental processes in controlling soil-plant transfer. As many of these processes are, to a lesser or greater extent, climate-dependent, it can be argued that climate/environmental change will impact soil-to-plant transfer of radionuclides and subsequent transfers in specific environments. This discussion attempts to highlight the possible role of climatic and climate-dependent variables in soil-to-plant transfer processes within the overall predictions of climate/environmental change. The work is speculative, and intended to stimulate debate on a theme that radioecology has either ignored or avoided in recent years.


Journal of Environmental Radioactivity | 2004

Assessment of the radiological impacts of historical coal mining operations on the environment of Ny-Ålesund, Svalbard

Mark Dowdall; K. Vicat; I. Frearson; Sebastian Gerland; B. Lind; G. Shaw

Mineral extraction activities, such as those conducted by oil, gas and coal industries, are widespread throughout the Arctic region. Waste products of these activities can result in significant contributions to the radioactive burden of the surrounding environment due to increased concentrations of naturally occurring radioactive materials (NORM) to levels that would not normally be found in the environment. Coal mining operations commenced in the early 1900s on Svalbard and have been conducted at a variety of locations on the archipelago since then. Coal contains radionuclides of the uranium and thorium series as well as 40K. Extraction and processing of coal can result in releases of these radionuclides to the broader environment with subsequent impact on the human and non-human inhabitants of the area. This paper presents the results of a study on environmental radioactivity resulting from historical coal mining operations conducted at Ny-Alesund, Spitsbergen, in the Svalbard archipelago. Activity concentrations of radionuclides found in materials associated with these operations are presented as well as the results of a spatial dosimetric survey conducted over an area affected by coal mining.


Soil & Sediment Contamination | 2005

Assessment of Elevated Radionuclide Levels in Soils Associated with an Avian Colony in a High Arctic Environment

Mark Dowdall; Justin P. Gwynn; G. W. Gabrielsen; B. Lind

This article presents the results of an investigation into the occurrence of elevated levels of radionuclides in soils associated with a seabird colony in the Arctic. Soils and other materials were collected from a seabird colony (primarily composed of kittiwakes) in Kongsfjorden, located in the High Arctic archipelago of Svalbard. The samples were analyzed for a suite of gamma emitting natural and anthropogenic radionuclides, including 137Cs and nuclides of the 238U and 232Th series, to establish the level of enrichment and the behavior of the radionuclides in the immediate area. The results indicate that soils near the colony exhibit enrichment factors of 8 for 137Cs, 5 for 238U and 2 for 226Ra compared to the nuclide content of soils from the general area. The spatial patterns of the nuclides in the soil are consistent with enrichment of the soil via run-off draining from a large accumulation of fecal and nesting material that has developed at the base of the colony. 137Cs ingress to the soil appears to have peaked at some point in the past as patterns of enrichment at the colony are different to those exhibited by 238U, which must be assumed to be a steady state contribution. The means of introduction of radionuclides to the colony remains unclear but the transfer of 137Cs from the marine environment to the terrestrial environment via the food chain and deposition of feces is discussed.


Marine Pollution Bulletin | 2010

On the potential for climate change impacts on marine anthropogenic radioactivity in the Arctic regions

Michael Karcher; I. H. Harms; W.J.F. Standring; Mark Dowdall; P. Strand

Current predictions as to the impacts of climate change in general and Arctic climate change in particular are such that a wide range of processes relevant to Arctic contaminants are potentially vulnerable. Of these, radioactive contaminants and the processes that govern their transport and fate may be particularly susceptible to the effects of a changing Arctic climate. This paper explores the potential changes in the physical system of the Arctic climate system as they are deducible from present day knowledge and model projections. As a contribution to a better preparedness regarding Arctic marine contamination with radioactivity we present and discuss how a changing marine physical environment may play a role in altering the current understanding pertaining to behavior of contaminant radionuclides in the marine environment of the Arctic region.


Marine Pollution Bulletin | 2002

The accidental sinking of the nuclear submarine, the Kursk: monitoring of radioactivity and the preliminary assessment of the potential impact of radioactive releases.

Ingar Amundsen; M. Iosjpe; O. Reistad; B. Lind; K. Gussgaard; P. Strand; S. Borghuis; M. Sickel; Mark Dowdall

Measurements of samples taken from the close vicinity of the Kursk during two expeditions to the site in August and October 2000, indicate that no leakage of radionuclides from the reactors has been observed. Only background levels in the range 0.0-0.1 microSv/h have been measured by use of the remote operating vehicle (ROV) or by the divers working on and inside the submarine. Preliminary model calculations based on two different scenarios, representing short- and long-term releases of 100% of the reactors radionuclide inventory, show that the impact on man and the environment from the Kursk should not be deemed very serious. The conservative estimates indicate a maximum 137Cs activity concentration in fish in the order of about 80-100 Bq/kg and a total collective dose of 97 manSv.


Environmental Modelling and Software | 2016

Model analysis of worst place scenarios for nuclear accidents in the northern marine environment

Frank Kauker; Thomas Kaminski; Michael Karcher; Mark Dowdall; J.E. Brown; A. Hosseini; P. Strand

The North and Nordic Seas contains some of the worlds most important fishery resources and is an area of significant traffic involving nuclear powered vessels and transports of nuclear and radioactive materials. Consumer awareness to even rumors of radioactive contamination imparts a special vulnerability to this region. The effective assignation of emergency resources, design of monitoring programs and provision of information regarding accidents relies upon an a-priori analysis of potential impacts. To this end, an adjoint sensitivity analysis regarding potential impacts on the most important regional fishery was conducted with a view towards development of a system capable of providing information regarding potential contaminant dispersal from any point within the North and Nordic Seas. Results indicate that the area is potentially vulnerable to releases of radioactive materials over a much wider area than has previously considered. An adjoint sensitivity analysis of the northern marine area was conducted.Potential impacts on the most important regional fishery were assessed.The fishery is vulnerable to releases of contaminants over a much wider area than previously considered.


The Scientific World Journal | 2002

Recent Levels of Technetium-99 in Seawater at the West Coast of Svalbard

Sebastian Gerland; B. Lind; Mark Dowdall

Seawater from the western coast of Svalbard was sampled in the spring and summer of 2000 to determine levels of technetium-99 (99Tc), a conservative-behaving, manmade radionuclide originating from European nuclear reprocessing plants. This paper deals with the recent levels of this radionuclide in seawater and with the link between an Arctic fjord, Kongsfjorden, and the Western Spitsbergen Current (WSC), investigated using 99Tc results. By means of the WSC, the 99Tc radionuclides ultimately reach the eastern Fram Strait west of Spitsbergen (the largest island of the Svalbard archipelago). Results from oceanographic modelling and sea ice observations indicate a direct coupling between Kongsfjorden and the area west of it. The findings in connection with new radionuclide results presented in this paper concur with these assumptions. Furthermore they indicate that the inner part of Kongsfjorden is also well linked to the WSC. Surface seawater from the central part of the WSC, sampled during a cruise with RV Polarstern in the summer of 2000, shows a higher level of 99Tc than those measured in Kongsfjorden in spring 2000. However, all levels measured in surface water are of the same order of magnitude. Data from sampling of deeper water in the WSC area provide information pertaining to the lateral distribution of 99Tc. The results, along with additional data from spring 2001, indicate that Kongsfjorden is suitable for monitoring the levels of 99Tc arriving in the European Arctic and that the sheltered setting of this fjord does not necessarily provide protection against pollution from the open sea.


Environmental Monitoring and Assessment | 2011

Application of an environmental impact assessment methodology to a site discharging low levels of radioactivity to a freshwater environment in Norway

A. Hosseini; J.E. Brown; Mark Dowdall; W.J.F. Standring; P. Strand

Significant shifts in opinion regarding environmental protection from ionising radiation have resulted in the development and availability of bespoke approaches for the assessment of impacts on wildlife from radioactive contaminants. The application of such assessment methodologies to actual situations, however, remains relatively limited. This paper describes the implementation of the ERICA Integrated Approach and associated tools within the context of routine discharges of radioactive materials to a freshwater environment. The article follows the implementation through its relevant stages and discusses strengths and weaknesses of the approach in relation to the case study. For current discharge levels, 137Cs and 60Co constitute the main dose contributors to the majority of reference organisms studied, although 241Am and 3H are the main contributors for the phyto- and zooplankton categories. Patterns are observed depending on whether the reference organism is sediment-associated or not. At current discharge levels, none of the reference organisms exceeded or approached the selected screening level, and impacts on biota could be regarded as negligible.


International Journal of Environmental Research and Public Health | 2009

Overview of Dose Assessment Developments and the Health of Riverside Residents Close to the “Mayak” PA Facilities, Russia

W.J.F. Standring; Mark Dowdall; P. Strand

The Norwegian Radiation Protection Authority (NRPA) has been involved in studies related to the Mayak PA and the consequences of activities undertaken at the site for a number of years. This paper strives to present an overview of past and present activities at the Mayak PA and subsequent developments in the quantification of health effects on local populations caused by discharges of radioactive waste into the Techa River. Assessments of doses to affected populations have relied on the development of dose reconstruction techniques for both external and internal doses. Contamination levels are typically inhomogeneous and decrease with increasing distance from the discharge point. Citations made in this paper give a comprehensive, though not exhaustive, basis for further reading about this topic.

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B. Lind

Norwegian Radiation Protection Authority

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Justin P. Gwynn

Norwegian Radiation Protection Authority

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J.E. Brown

Norwegian Radiation Protection Authority

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P. Strand

Norwegian Radiation Protection Authority

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A. Hosseini

Norwegian Radiation Protection Authority

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W.J.F. Standring

Norwegian Radiation Protection Authority

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Ø.G. Selnæs

Norwegian Radiation Protection Authority

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Michael Karcher

Alfred Wegener Institute for Polar and Marine Research

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Anne Liv Rudjord

Norwegian Radiation Protection Authority

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