Trends in sediment metal concentrations in the River Avoca, South-East Ireland
- 1 December 2004
- journal article
- Published by Springer Science and Business Media LLC in Environmental Geochemistry and Health
- Vol. 26 (4), 411-419
- https://doi.org/10.1007/s10653-005-0307-0
Abstract
Variation in sediment metal concentrations in the River Avoca, which is severely polluted by acid mine drainage (AMD) discharged from the abandoned sulphur and copper mines in Avoca, is reported. A survey of surface and subsurface sediments was repeated after seven years during exceptionally low flow conditions in 2001. The present study found that the reference (up-stream) site used in the original 1994 study was itself impacted by AMD, showing sediment metal enrichment by AMD to be greater than originally thought. The new reference site contained elevated Pb (570 µg g−1) in the subsurface sediment due to abandoned Pb-Zn mines 25 km further upstream. Concentrations of Cu (43 µg g−1), Zn (349 µg g−1) and Fe (4.0%) were normal for uncontaminated rivers. All the downstream sites showed sediment metal enrichment arising from the AMD (Cu and Zn p < 0.001; Fe p < 0.01). Subsurface concentrations of metals immediately below the mixing zone were Cu 904 µg g−1 (sd 335), Zn 723 µg g−1 (sd 93), Fe 6.3% (sd 1.5) and Pb 463 µg g−1 (sd 279). Monthly variation in metal concentrations at sites was not significantly different (p > 0.05). Although surface sediment metal concentrations were more variable, they followed similar trends to subsurface sediment. There were no significant differences in the subsurface sediment concentrations for either Cu or Zn over the period 1994 and 2001 immediately below the mines, although at the lowest site Zn had decreased by 35% over the period (p < 0.01). However there was a significant (p < 0.01) decrease over the period in the Fe concentration at all the impacted sites. This corresponds to a reduction in Fe concentration in the AMD and indicates that some remediation has occurred in the river since 1994.Keywords
This publication has 7 references indexed in Scilit:
- Mine WaterPublished by Springer Science and Business Media LLC ,2002
- Acid mine drainage composition and the implications for its impact on lotic systemsWater Research, 1998
- Environmental impact and remediation of acid mine drainage: a management problemEnvironmental Geology, 1997
- Metal contamination of riverine sediments below the Avoca mines, south east IrelandEnvironmental Geochemistry and Health, 1997
- A substrate classification index for the visual assessment of the impact of acid mine drainage in lotic systemsWater Research, 1996
- Seasonal variation of metal contamination of riverine sediments below a copper and sulphur mine in South-East IrelandWater Science & Technology, 1996
- Trace metal analysis on polluted sedimentsEnvironmental Technology Letters, 1980