Measurement and interpretation of 210Pb, 137Cs, 134Cs and 241Am profiles in relation to sedimentation in some Irish lakes

Nowlan, N. V.; Mitchell, P.I.; Murray, D. A.; Vintró, Luis León; Seymour, E. M.

doi:10.1080/03680770.1998.11901650

Cited by 5 publications

(5 citation statements)

References 2 publications

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“…Estimates of sediment age and accumulation rates based on such coarsely resolved analyses have to be treated with caution. However, the estimated accumulation rate for Dan (53°23′N, 6°16′E) corresponds closely with published 210 Pb‐based data for the same site (Nowlan et al . 2000), while the accuracy of the SCP‐based chronology for Nambrackkeagh (53°34′N, 9°46′E) was confirmed using recently available 210 Pb‐based accumulation rate data (E. McGee, unpublished data).…”

Section: Methodssupporting

confidence: 88%

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

Leira

Jordan

Taylor

et al. 2006

Journal of Applied Ecology

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Summary1. The European Union (EU) Water Framework Directive (WFD) requires that member states establish type-specific reference conditions for all waterbodies, including freshwater lakes. This presents a problem in those locations where human activity has resulted in significant changes to the biological, chemical and physical characteristics of waterbodies. 2. Seventy-six oligotrophic and meso-oligotrophic [0 -19 µ g total phosphorus (TP) L ] lakes thought to be relatively unimpacted by human activity have been nominated as candidate reference lakes (CRL) by the Irish Environmental Protection Agency. This research has used palaeolimnological (lake sediment-based) techniques to test the actual and historical ecological site-specific status of a representative selection of these CRL. Where the temporal record of sedimentation was sufficiently long, the study adopted c. 1850  as the primary baseline date for reference conditions. 3. Short sediment cores were obtained from the deepest parts of 35 CRL, and chronologies were established from profiles of spheroidal carbonaceous particles (SCP). Twenty-two cores of sediment appeared to date back to c. 1850 on the basis of SCP concentrations. Unless the SCP chronologies suggested otherwise, diatom assemblages present in top and bottom samples from the cores were used as proxies of, respectively, present-day and reference conditions. Past lake water pH (DI-pH) and TP concentration (DI-TP) were inferred from the diatom data. Higher resolution sampling (up to five sediment samples per core) was adopted at seven sites where the SCP-based chronology was more robust and for at least one core from each of the most common types of CRL. Sediment chemistry data were determined to identify possible anthropogenic drivers of the observed changes in the diatom assemblages. 4. Ordination and dissimilarity measures identified the main patterns of variation in the diatom data. Eleven of 34 CRL for which diatom data were available showed little or no change in biological status between core top and bottom samples. Core bottom samples in six of these dated back to pre-or c. 1850 and reference (and high ecological) status could therefore be confirmed in these cases. The estimated age of core bottom samples in the remaining five cores was in the period just after c . 1850 to c. 1950  (four cores) or was impossible to determine (one core). Twenty-three (68%) of the CRL sampled showed biologically important deviation from the reference condition, with acidification and nutrient enrichment seemingly the main causes of change. Catchment disturbance, notably peat erosion possibly linked to recent afforestation, also appeared to have been a factor in some cases. 5. Synthesis and applications. This study provides the first systematic examination of changes to water quality in (perceived) pristine lakes over the last c . 150 years for Ireland, and demonstrates the potential of palaeolimnology to support the implementation of the WFD. The results indicate that diatom communities in low alkalinit...

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Section: Methodssupporting

confidence: 88%

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

Leira

Jordan

Taylor

et al. 2006

Journal of Applied Ecology

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“…The estimated accumulation rates are consistent with those reported by Nowlan et al (2000) for other lakes throughout Ireland. In that study, two distinct types of lakes were identified on the basis of sediment accumulation.…”

Section: Lead-210 Chronologiessupporting

confidence: 89%

210Pb-dating of a lake sediment core from Lough Carra (Co. Mayo, western Ireland): use of paleolimnological data for chronology validation below the 210Pb dating horizon

O’Reilly

Vintró

Mitchell

et al. 2011

Journal of Environmental Radioactivity

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“…The average annual 210 Pbex deposition rate for Ballywillan was 74.2 Bq m -2 yr -1 . This is similar to values for other small Irish lakes analyzed by Nowlan et al (43), where rapid accumulation was also found to occur.…”

Section: Resultssupporting

confidence: 91%

Retrospective Search for Evidence of the 1957 Windscale Fire in NE Ireland Using ¹²⁹I and Other Long-Lived Nuclides

Gallagher

McGee

Mitchell

et al. 2005

Environ. Sci. Technol.

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The accident at Windscale in October 1957 resulted in the release to the atmosphere of a large quantity of radioactivity. The presented work is a retrospective search for evidence of contamination from the accident in the northeastern region of Ireland. A lake yielding a high-resolution sedimentary record was identified near the northeast coast of Ireland. This site was used to reconstruct the history of radionuclide input to the region, based on the analysis of a set of cores extracted from the lake. A chronology for sediment accumulation within the lake was established using radioisotopic dating techniques (including 270Pb). High-resolution gamma and alpha spectrometry techniques were used to quantify concentrations of 137Cs, 239,240Pu and 241Am, all of which were released during the accident. The primary radioactive component of the release was 131I (T1/2 = 8 days), but this short-lived isotope has long since decayed. However, 129I (T1/2 = 1.57 x 10(7) years) was also released during the accident, and in a known ratio to 131I. Recent advances in accelerator mass spectrometry now make it feasible to measure 129I at ultra-trace level and thereby retrospectively reconstruct 131I deposition. Clearly resolved concentration profiles for 137Cs, 239,240Pu and 241Am in the lake cores reflect known historical fallout trends. The data suggest that any contamination from the Windscale fire that might have reached this catchment has been overwritten by input from the testing of nuclear weapons in the atmosphere. A time-series for 129I in lake sediment shows that concentrations in recent sediments are approximately 10 times greater than concentrations recorded in strata corresponding to the period of maximum fallout of other radionuclides from atmospheric testing of nuclear weapons (1964). These recent increases in 129I are attributed to increased emissions from the nuclear industry. The study yields no evidence of any enhancement in radioisotope concentrations, over and above global fallout, in strata dated to 1957, and we conclude that contamination from the Windscale fire had negligible impact on the northeastern region of Ireland.

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Measurement and interpretation of ²¹⁰Pb, ¹³⁷Cs, ¹³⁴Cs and ²⁴¹Am profiles in relation to sedimentation in some Irish lakes

Cited by 5 publications

References 2 publications

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

210Pb-dating of a lake sediment core from Lough Carra (Co. Mayo, western Ireland): use of paleolimnological data for chronology validation below the 210Pb dating horizon

Retrospective Search for Evidence of the 1957 Windscale Fire in NE Ireland Using ¹²⁹I and Other Long-Lived Nuclides

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Measurement and interpretation of 210Pb, 137Cs, 134Cs and 241Am profiles in relation to sedimentation in some Irish lakes

Cited by 5 publications

References 2 publications

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

Assessing the ecological status of candidate reference lakes in Ireland using palaeolimnology

210Pb-dating of a lake sediment core from Lough Carra (Co. Mayo, western Ireland): use of paleolimnological data for chronology validation below the 210Pb dating horizon

Retrospective Search for Evidence of the 1957 Windscale Fire in NE Ireland Using 129I and Other Long-Lived Nuclides

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Measurement and interpretation of ²¹⁰Pb, ¹³⁷Cs, ¹³⁴Cs and ²⁴¹Am profiles in relation to sedimentation in some Irish lakes

Retrospective Search for Evidence of the 1957 Windscale Fire in NE Ireland Using ¹²⁹I and Other Long-Lived Nuclides