Developing a critical load approach for national risk assessments of atmospheric metal deposition

Hall, Jane R.; Ashmore, Mike; Fawehinmi, Joseph; Jordon, Crawford; Lofts, Stephen; Shotbolt, Laura; Spurgeon, David J.; Svendsen, Claus; Tipping, Edward. 2006 Developing a critical load approach for national risk assessments of atmospheric metal deposition. Environmental Toxicology and Chemistry, 25 (3). 883-890.

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The critical load approach has been proposed for evaluation of the need to reduce atmospheric emissions of metals that lead to transboundary transport and deposition across Europe. The present study demonstrates and evaluates the application of a critical load approach for national-scale risk assessment of metal deposition in the United Kingdom. Critical load maps, calculated using critical limits based on pH-dependent free metal ion activities, are presented. Current concentrations of lead and cadmium in soils are compared with two sets of critical limit values: First, limits based on the reactive soil concentration, and second, a pH-dependent free ion critical limit function, which takes into account variable soil characteristics across the country. The use of these two models leads to different conclusions about which areas of the United Kingdom are at greatest risk, partly because of differences in the range of values of pH and organic matter in soils used in ecotoxicological experiments and in the national database. Critical loads were calculated based on free ion critical limits; the critical loads were lowest in the south and east of the country and were associated with higher soil pH, lower runoff, and lower soil organic matter

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: CEH Programmes pre-2009 publications > Biogeochemistry
UKCEH and CEH Sections/Science Areas: _ Ecological Risk
_ Environmental Chemistry & Pollution
ISSN: 0730-7268
Format Availability: Electronic, Print
Additional Keywords: Critical loads, Critical limits, Free ion toxicity, Cadmium, Lead
NORA Subject Terms: Atmospheric Sciences
Date made live: 25 Jun 2007 16:08 +0 (UTC)

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