http://earthwise-staging.bgs.ac.uk/index.php?action=history&feed=atom&title=OR%2F18%2F011_UK_aquifersOR/18/011 UK aquifers - Revision history2026-04-19T23:15:27ZRevision history for this page on the wikiMediaWiki 1.42.3http://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=44035&oldid=prevDbk at 11:22, 2 December 20192019-12-02T11:22:08Z<p></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>| DO = <LOD<br>NO<sub>3</sub> = <LOD<br>Eh = 0–+50<br>NH<sub>4</sub> = 0.05–0.85<br>Fe = 7–170<br>Mn = 4–57 </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>| DO = <LOD<br>NO<sub>3</sub> = <LOD<br>Eh = 0–+50<br>NH<sub>4</sub> = 0.05–0.85<br>Fe = 7–170<br>Mn = 4–57 </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>| Edmunds et al. (1984)<ref name="Edmunds 1984"><del style="font-weight: bold; text-decoration: none;">EDMUNDS, W M, MILES, D L, and COOK, J M. 1984. A comparative study of sequential redox processes in three British aquifers. 55–70 in ''Hydrochemical Balances in Freshwater''. ERIKSSON, E (editor). Vol.&nbsp;150. (Wallingford: IAHS-AISH.) </del></ref></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>| Edmunds et al. (1984)<ref name="Edmunds 1984"></ref></div></td></tr>
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</table>Dbkhttp://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=44034&oldid=prevDbk at 11:20, 2 December 20192019-12-02T11:20:59Z<p></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Very old saline water, probably emplaced during Rutland Formation times.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># Very old saline water, probably emplaced during Rutland Formation times.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Edmunds (1973, 1976) studied hydrochemical variations along a 28-km flow line in the southern Lincolnshire Limestone in 1969 and found solution, redox and ion-exchange reactions, SO<sub>4</sub> reduction and mixing with saline formation water to all be important processes within the aquifer. Edmunds and Walton (1983) re-sampled the same aquifer profile after 10 years to look at hydrogeochemical evolution with time and found that the overall sequence was remarkably similar in both distance from outcrop and absolute concentration but that, close to the redox boundary, down-gradient increases in Ca, SO<sub>4</sub> Cl and NO<sub>3</sub> had occurred, together with a less abrupt redox boundary. Edmunds and Walton (1983)<ref name="Edmunds 1983" <del style="font-weight: bold; text-decoration: none;"> </del>><del style="font-weight: bold; text-decoration: none;">EDMUNDS, W, and WALTON, N. 1983. The Lincolnshire Limestone—hydrogeochemical evolution over a ten-year period. ''Journal of Hydrology'', Vol.&nbsp;61, 201–211.</del></ref> postulated that these changes were initiated by the migration of agrichemical pollutants and that the results indicate that the aquifer has a considerable capacity for in-situ NO<sub>3</sub> reduction.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Edmunds (1973, 1976) studied hydrochemical variations along a 28-km flow line in the southern Lincolnshire Limestone in 1969 and found solution, redox and ion-exchange reactions, SO<sub>4</sub> reduction and mixing with saline formation water to all be important processes within the aquifer. Edmunds and Walton (1983) re-sampled the same aquifer profile after 10 years to look at hydrogeochemical evolution with time and found that the overall sequence was remarkably similar in both distance from outcrop and absolute concentration but that, close to the redox boundary, down-gradient increases in Ca, SO<sub>4</sub> Cl and NO<sub>3</sub> had occurred, together with a less abrupt redox boundary. Edmunds and Walton (1983)<ref name="Edmunds 1983"></ref> postulated that these changes were initiated by the migration of agrichemical pollutants and that the results indicate that the aquifer has a considerable capacity for in-situ NO<sub>3</sub> reduction.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Howard (1985)<ref name="Howard 1985">HOWARD, K W F. 1985. Denitrification in a major limestone aquifer. ''Journal of Hydrology'', Vol.&nbsp;76, 265–280. </ref> defines water type in his study of the Lincolnshire Chalk by origin and his confined water represents old low-salinity water that replenished the aquifer when groundwater levels began to recover after the Devensian glacial episode. This has low N but does not necessarily represent denitrification as initial N would have depended on vegetation at the time of recharge. Some of this reducing water contained NH<sub>4</sub>.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Howard (1985)<ref name="Howard 1985">HOWARD, K W F. 1985. Denitrification in a major limestone aquifer. ''Journal of Hydrology'', Vol.&nbsp;76, 265–280. </ref> defines water type in his study of the Lincolnshire Chalk by origin and his confined water represents old low-salinity water that replenished the aquifer when groundwater levels began to recover after the Devensian glacial episode. This has low N but does not necessarily represent denitrification as initial N would have depended on vegetation at the time of recharge. Some of this reducing water contained NH<sub>4</sub>.</div></td></tr>
</table>Dbkhttp://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=44033&oldid=prevDbk at 11:18, 2 December 20192019-12-02T11:18:51Z<p></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Evidence of denitrification comes from the confined (anoxic) parts of some British aquifers from the work of Edmunds and others. This has also been confirmed by the occurrence of modern tritium-enriched groundwater with negligible NO<sub>3</sub> (Lawrence and Foster, 1986<ref name="Lawrence 1986">LAWRENCE, A R, and FOSTER, S S D. 1986. Denitrification in a limestone aquifer in relation to the security of low-nitrate groundwater supplies. ''Journal of the Institution of Water Engineers and Scientists'', Vol.&nbsp;40, 159–172. </ref>) and from the demonstration of appropriate bacteria in core samples.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Evidence of denitrification comes from the confined (anoxic) parts of some British aquifers from the work of Edmunds and others. This has also been confirmed by the occurrence of modern tritium-enriched groundwater with negligible NO<sub>3</sub> (Lawrence and Foster, 1986<ref name="Lawrence 1986">LAWRENCE, A R, and FOSTER, S S D. 1986. Denitrification in a limestone aquifer in relation to the security of low-nitrate groundwater supplies. ''Journal of the Institution of Water Engineers and Scientists'', Vol.&nbsp;40, 159–172. </ref>) and from the demonstration of appropriate bacteria in core samples.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Sequential redox processes have been described in three contrasting principal UK aquifers that have confined zones (Edmunds and Walton, 1983<ref name="Edmunds 1983">EDMUNDS, W, and WALTON, N. 1983. The Lincolnshire Limestone—hydrogeochemical evolution over a ten-year period. ''Journal of Hydrology'', Vol.&nbsp;61, 201–211. </ref>; Edmunds et al., 1982<ref name="Edmunds 1982"><del style="font-weight: bold; text-decoration: none;">EDMUNDS, W M, BATH, A H, and MILES, D L. 1982. Hydrochemical evolution of the East Midlands Triassic sandstone aquifer, England. ''Geochimica et Cosmochimica Acta'', Vol.&nbsp;46, 2069–2081.</del></ref>; Edmunds et al., 1984<ref name="Edmunds 1984">EDMUNDS, W M, MILES, D L, and COOK, J M. 1984. A comparative study of sequential redox processes in three British aquifers. 55–70 in ''Hydrochemical Balances in Freshwater''. ERIKSSON, E (editor). Vol.&nbsp;150. (Wallingford: IAHS-AISH.)</ref></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Sequential redox processes have been described in three contrasting principal UK aquifers that have confined zones (Edmunds and Walton, 1983<ref name="Edmunds 1983">EDMUNDS, W, and WALTON, N. 1983. The Lincolnshire Limestone—hydrogeochemical evolution over a ten-year period. ''Journal of Hydrology'', Vol.&nbsp;61, 201–211. </ref>; Edmunds et al., 1982<ref name="Edmunds 1982"></ref>; Edmunds et al., 1984<ref name="Edmunds 1984">EDMUNDS, W M, MILES, D L, and COOK, J M. 1984. A comparative study of sequential redox processes in three British aquifers. 55–70 in ''Hydrochemical Balances in Freshwater''. ERIKSSON, E (editor). Vol.&nbsp;150. (Wallingford: IAHS-AISH.)</ref></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* The Berkshire Chalk on the western rim of the London Basin has an average thickness of 250 m. It dips to the east, is confined below Palaeogene sands and clays in the centre of the syncline and is underlain by the Upper Greensand and then the Gault Formation that serves as the basal aquiclude. It is a dual-porosity aquifer with moderate transmissivity in this area (270–450 m<sup>2</sup>/day) decreasing with depth.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>* The Berkshire Chalk on the western rim of the London Basin has an average thickness of 250 m. It dips to the east, is confined below Palaeogene sands and clays in the centre of the syncline and is underlain by the Upper Greensand and then the Gault Formation that serves as the basal aquiclude. It is a dual-porosity aquifer with moderate transmissivity in this area (270–450 m<sup>2</sup>/day) decreasing with depth.</div></td></tr>
</table>Dbkhttp://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=44032&oldid=prevDbk: /* Lincolnshire Limestone */2019-12-02T11:17:47Z<p><span dir="auto"><span class="autocomment">Lincolnshire Limestone</span></span></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>====Lincolnshire Limestone====</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>====Lincolnshire Limestone====</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Foster et al. (1985)<ref name="Foster 1985"><del style="font-weight: bold; text-decoration: none;">FOSTER, S S D, KELLY, D P, and JAMES, R. 1985. The evidence for zones of biodenitrification in British aquifers. 356–369 in ''Planetary Ecology''. CALDWELL, D E, BRIERLEY, J A, and BRIERLEY, C L (editors). (New York: Van Nostrand Reinhold Company Incorporated.)</del></ref> provided NO<sub>3</sub>, tritium and bacterial activity data for cores taken from the Lincolnshire Limestone that supported denitrification, e.g., penetration of thermonuclear tritium further down-dip from outcrop than both NO<sub>3</sub> and DO. Wilson et al. (1990)<ref name="Wilson 1990">WILSON, G B, ANDREWS, J N, and BATH, A H. 1990. Dissolved gas evidence for denitrification in the Lincolnshire Limestone groundwaters, eastern England. ''Journal of Hydrology'', Vol.&nbsp;113, 51–60. </ref> also presented evidence for denitrification that included concentrations of excess nitrogen and isotopic ratios.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Foster et al. (1985)<ref name="Foster 1985"></ref> provided NO<sub>3</sub>, tritium and bacterial activity data for cores taken from the Lincolnshire Limestone that supported denitrification, e.g., penetration of thermonuclear tritium further down-dip from outcrop than both NO<sub>3</sub> and DO. Wilson et al. (1990)<ref name="Wilson 1990">WILSON, G B, ANDREWS, J N, and BATH, A H. 1990. Dissolved gas evidence for denitrification in the Lincolnshire Limestone groundwaters, eastern England. ''Journal of Hydrology'', Vol.&nbsp;113, 51–60. </ref> also presented evidence for denitrification that included concentrations of excess nitrogen and isotopic ratios.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Bottrell et al. (2000) more recently explored the control exerted on bacterial reduction reactions by the dual-porosity characteristics of the Lincolnshire Limestone. By analogy with SO<sub>4-</sub> reducing reactions in the aquifer, they concluded that the potential for denitrification in the shallow confined zone is poor. Reaction rates were limited by lack of an electron donor in the fissures; were NO<sub>3</sub> to diffuse into the pores where organic carbon and sulphides were present, NO<sub>3</sub>-reducing bacteria would be excluded by the narrow pore throats of the matrix (similar to the Chalk).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Bottrell et al. (2000) more recently explored the control exerted on bacterial reduction reactions by the dual-porosity characteristics of the Lincolnshire Limestone. By analogy with SO<sub>4-</sub> reducing reactions in the aquifer, they concluded that the potential for denitrification in the shallow confined zone is poor. Reaction rates were limited by lack of an electron donor in the fissures; were NO<sub>3</sub> to diffuse into the pores where organic carbon and sulphides were present, NO<sub>3</sub>-reducing bacteria would be excluded by the narrow pore throats of the matrix (similar to the Chalk).</div></td></tr>
</table>Dbkhttp://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=43843&oldid=prevDbk: 1 revision imported2019-11-29T10:35:24Z<p>1 revision imported</p>
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<td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:35, 29 November 2019</td>
</tr><tr><td colspan="2" class="diff-notice" lang="en"><div class="mw-diff-empty">(No difference)</div>
</td></tr></table>Dbkhttp://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=43842&oldid=prevgeosource>Ajhil: /* Redox boundaries */2019-09-17T11:10:47Z<p><span dir="auto"><span class="autocomment">Redox boundaries</span></span></p>
<a href="http://earthwise-staging.bgs.ac.uk/index.php?title=OR/18/011_UK_aquifers&diff=43842">Show changes</a>geosource>Ajhil