No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Spatially representative sampling of both natural and anthropogenic deposits in the environment is limited by their inherent heterogenic distribution. This problem is compounded when trying to relate ground measurements which are spatially restricted to remote sensing observations which are not. This work examined these widely experienced problems in the context of the measurement of natural (K, U and Th) and anthropogenic ( 137Cs and ' 34Cs) radioactivity through the three techniques of soil sampling with laboratory based gamma ray spectrometry, in-situ gamma ray spectrometry, and airborne gamma ray spectrometry. These three methods were applied systematically to estimate the radioactivity across a tight geometry valley in Renfrewshire. Activity estimates from field based and airborne gamma spectrometry were compared with each other and with the results of high resolution gamma spectrometry of soil samples to examine the relationship between each method under variable topographic conditions. These results demonstrated that the distribution, and post depositional migration, of activity had important influences on all measurement techniques, and affected the ability to make comparisons between them. Further detailed studies were then conducted to examine these influences. The effects of variations in soil composition and characteristics on environmental gamma ray spectrometry were evaluated by calculation and experimental determination. Corrections to standard laboratory gamma spectrometric procedures were developed to improve systematic precisio:i. These investigations also reviewed soil sampling depth for direct effective comparison with in-situ gamma spectrometry. The effects of small scale sampling errors on activity estimates were demonstrated to have a quantifiable influence on the precision of activity estimation. Lateral variability of activity distribution of natural radioactivity and anthropogenic radioactivity deposited both from the atmosphere and from marine sources has been studied in detail at a number of sites. The extent of variability depends on the nature of activity, its deposition mode and local environmental characteristics. Spatial variability represents an important constraint on the interpretation of activity estimates derived from all methods examined, and on comparisons between them. Statistically representative sampling plans were developed and applied to enable spatial comparisons to be made between soil sample derived activity estimates and in-situ and remotely sensed observations. The influence of the vertical activity distribution on in-situ and airborne measurements has been recognised as an important variable affecting calibration. The use of the information from the scattered gamma ray spectrum to quantify and correct for source burial effects was examined in a series of modelling experiments. A relationship between 'Cs source burial and forward scattering was determined and subsequently applied to a salt marsh environment which showed pronounced subsurface maxima. A spectrally derived calibration correction coefficient was shown to account for variations in source burial across a single site. This provides a potential means for surmounting one of the principal limitations of in-situ gamma spectrometry. As a result of this work it has been possible to account for important environmental factors which affect gamma ray spectrometry in the laboratory, in the field and from aircraft. This has led to the development of sound methodology for comparison between sampling, field based and remote sensing techniques.

No description available.

The project has been concerned with the study of radon and other natural radionuclides in the U-238 decay series in the environment. The contribution made by radon and its daughter radionuclides to population radiation dose both in the air and in water supplies has been investigated. The natural radioactivity of the river water, stream water, sediments and freshwater mussels have been measured using a thick source alpha counting technique and γ-spectrometry (water samples were preconcentrated by manganese dioxide precipitation method). The ^226Ra activity ranged from 10-20 Bq m^-3 in the river and 4-30 Bq m^-3 in stream water. The highest values were found close to the source of the river where the water flowed through an area of igneous rocks. Such granite type rocks are enriched in uranium and thorium. Concentrations of radon and its daughters were measured, indoors and outdoors, using a grab sample technique. Outdoor concentrations were 10-30 Bq m^-3 depending on underlying rocks, meteorological condition (pressure, temperature, snow, rain), while indoor values ranged between 20 and 600 Bq m^-3 depending on radon input rate (source strength, ventilation rate and pressure inside the building). The relationship between the indoor ^222Rn concentration and ventilation rate was investigated. The radiation dose and the consequent risk due to inhalation of radon and its daughters were estimated. The annual effective dose equivalent ranged from 0.12 to 11 mSv. The radon concentrations in well waters were measured and were found to range between 3 and 76 Bq ℓ-1. This variation can be associated with different bedrock. A model predicting average indoor increments due to this source is presented and supported by a series of measurements made in the houses which were supplied by well water. The maximum annual effective dose equivalent from inhalation and ingestion was found to be 0.27 and 0.054 mSv respectively.

Retrospective urban air quality assessments are imperative in understanding human health effects of long-term (lifetime) exposures to pollution; however, historical pollution data are limited. Therefore, air pollution records captured in the sediments of small urban ponds, sedimentary archives sensitive to localised urban activity, have been explored within the lower Mersey Region (LMR), a heavily industrialised area with poor health amongst the population. Proxy pollution profiles derived from isotope chronologies and magnetic, trace metal, flyash and geochemical properties of sediments from four small urban ponds have yielded high-resolution air pollution histories (<300 years). These site specific air pollution signals reveal air quality impacts of localised urban development and demonstrate the integrity of sediment records from urban ponds. A cross-regional air pollution history, reconstructed using these local contamination signals, details spatial variations in pollution deposition across the LMR, spanning pre-industrial times to present day. Low -pre-1830 pollution levels reflect a time of pre-intensified industry in the LMR with post-1830 increases signifying the Industrial Revolution and establishment of the early chemical industry. Distinct pollution enhancement from -1900 to 1950 is attributed to population increases, industrial diversification and war-time demands on industry, pre-Clean Air Acts (1959). A complex cross-regional post-1950 signal reveals intra-urban variations reflecting urban expansions within the region, with pollution reductions observed post-1970, due to increasingly stringent air quality legislations, however, pollution does not consistently decline throughout the LMR, potentially, due to air quality impacts from increased road and air travel. This high-resolution cross-regional urban air pollution signal provides an alternative to reliance upon background air pollution signals recorded by remote UK lakes. Furthermore, these ponds are set amongst populations most as risk to exposure of urban PM, and demonstrate important spatial variations in pollution characteristics, as well as revealing how air pollution has changed over time. These air pollution histories may, therefore, be used to better understand possible health linkages in the LMR.