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Changing nutrient levels in Grasmere, English Lake District, during recent centuries (2005)

BARKER, P. A. ; PATES, J. M. ; PAYNE, R. J. ; [et al.]

Oxford, UK : Blackwell Science Ltd

Freshwater biology 50 (2005), S. 0

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ISSN: 1365-2427

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: 1. Historical nutrient changes in Grasmere were investigated using a 300-year record derived from six sediment cores. One core was investigated at high resolution for diatoms, total sedimentary phosphorus, and loss-on-ignition (LOI), and was dated using 210Pb and 137Cs. Six other cores were scanned for magnetic susceptibility, diatoms and LOI to confirm the stratigraphic integrity of the primary record.2. A rise in nutrient levels occurred after 1855 AD. This event was marked by a shift away from benthic diatom assemblages and a rise in Asterionella formosa. The onset of eutrophication from 1855 corresponds to the expansion of the local and tourist population in the area.3. The replacement of A. formosa with Cyclotella spp. ca 1945–65 indicates reduced nutrient loads, possibly because of enhanced flushing brought about by the seasonal rainfall distribution.4. After 1965 a step-wise increase in both absolute and relative amounts of Asterionella was found. High sedimentary P and diatom inferred TP confirmed the high nutrient loading of the lake. Nutrient increase is attributable to problems with the Grasmere village sewage system and the installation of a wastewater treatment works (WwTW) on the River Rothay in 1971. Modifications to the WwTW in 1982 caused an initial improvement, but have not led to a full recovery to pre-1965 ecological conditions.5. The diatom record indicates a further improvement after 1990 by a return toward Achnanthes minutissima.6. The sedimentary archive of sensitive sites provides important benchmarks against which to judge the attainment of water quality targets.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2427.2005.01439.x

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The development of an alpha/beta separation liquid scintillation cocktail for aqueous samples (1993)

Pates, J. M. ; Cook, G. T. ; Mackenzie, A. B. ; [et al.]

Springer

Journal of radioanalytical and nuclear chemistry 172 (1993), S. 341-348

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ISSN: 1588-2780

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering

Notes: Abstract Scintillation cocktail components were studied with regard to their impact on pulse decay discimination (PDD) and hence the separation of alpha from beta activity, using a Packard 2250 CA α/β. Di-isopropyl naphthalene (DIN) was found to be the most suitable solvent, both from safety considerations and also the fact that it acts in a very similar manner to naphthalene in stretching the pulses produced at the photomultiplier tube anode and hence enhancing the separation. Increasing the surfactant concentration and the use of dimethylanthracene (DMA) as secondary fluor degraded the cocktail's performance. PMT anode pulse shapes were found to be a useful indicator of PDD efficiency but could not give a quantitative guide.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02041854

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