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Title: The use of Sphagnum as an indicator of airborne metals in the environment
Author: Smith, S.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1978
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This thesis reports on the geographical distribution of airborne metals in the South Wales environment, particularly in the Swansea region, as indicated by the analyses of Sphagnum moss samples. An initial survey in the Swansea region using natural populations of Sphaqnum moss found elevated levels of several metals - Cd, Co, Cu, Ni, Pb and Zn - in those samples growing immediately downwind of the Lower Swansea Valley. A comparison with samples from other areas is made. A subsequent survey of the same area, but using transplanted Sphagnum moss samples enclosed in nylon mesh packets (moss-bags), pinpointed several industrial sources of airborne metals. When one of these sources emitting Zn, Pb,and Cd permanently closed down, levels of these metals fell dramatically while other metals - Ni, Co and Cu - remained about the same. Also presented are the results of a comparative exercise, whereby metals retained on moss-bags are compared with corresponding results, obtained concurrently by AERE, Harwell, by three methods - a total deposit gauge, a dry deposit gauge and an air concentration gauge. The deposit gauges were found to sample the atmospheric aerosol in a conformable manner. However, because of their dependence on wind speed and their differential retention of different particle sizes, deposit gauges such as moss-bags cannot be used to indicate air concentration directly. During the winter and summer of 1973 over 400 moss-bags were exposed at sites across the whole of South Wales and subsequently analysed for Ni, Co, Cu, Cd, Pb, Zn, Fe, Mn, Ca and Mg. Three broad classes of metal levels were identified (1) low metal accumulations, in rural areas west of Swansea; (ii) higher metal accumulations in areas east of Swansea and (iii) highly elevated metal accumulations associated with individual sites or locations.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available