Hydrological and geochemical controls governing the distribution of trace metals in a mine-impacted lake

• Published in: Environmental earth sciences Vol. 43; no. 4; pp. 408 - 418
• Main Authors: MARTIN, A. J, CALVERT, S. E
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.02.2003; Springer Nature B.V
• Subjects: Acid mine drainage; Bottom sediments; Dry season; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Freshwater; Geochemistry; Hydrology; Lake basins; Lakes; Metal concentrations; Mineralogy; Peru, Junin L; Pollution, environment geology; Rainy season; Seasonal variations; Seasons; Sediment transport; Silicates; Soil and rock geochemistry; Spatial distribution; Surface water; Trace elements; Trace metals; Water circulation; Water geochemistry; Zinc; Peru; Peru, Lago Junin; Peru, Junin, Junin L; South America; particulate matters; trace metals; metals; Mine tailings; Lake; pollution; dams; spatial distribution; enrichment; hydrochemistry; copper; dissolved materials; lakes; zinc; rivers; accumulation; concentration; mining; loading; lead; surface water; mines; lake sediments; sediment transport; tailings; Peru
• ISSN: 0943-0105; 1866-6280; 1432-0495; 1866-6299
• DOI: 10.1007/s00254-002-0650-8

Factors controlling the distribution of mining-derived Cu, Pb and Zn in the waters and bottom sediments of a large Andean lake (Lago Junin, Peru) have been assessed based on sample collections in May/June 1997 (dry season) and February/March 1998 (wet season). Relatively low levels of trace metals detected in surface waters of the lake during the dry season contrasted greatly with the high values observed during the wet period. Dry season concentrations of total Zn, Cu and Pb in the central lake basin averaged 41, 4.4 and 0.24 µg/L, respectively. In contrast, the respective wet season concentrations of total Zn, Cu and Pb in areas of the main basin ranged up to 387, 52 and 40 µg/L. The seasonal variability in metal concentrations largely reflects an increase in the concentration of particulate metal phases during the wet season. Such observations can be attributed to changes in sediment loadings associated with mining-derived river inputs and changes in lake circulation resulting from hydroelectric dam operations. Surface sediments are characterized by lake-wide enrichments of Zn, Cu and Pb, with maximum concentrations reaching as high as 5, 0.25 and 0.7 wt%, respectively. Estimated rates of authigenic metal accumulation are not sufficient to account for the elevated metal concentrations in the main basin of the lake, indicating that metal distributions are governed by the accumulation of metal-rich particulates. Variations in the spatial distributions of Zn, Cu and Pb are suggested to be a function of varying host phases and textural sorting.[PUBLICATION ABSTRACT]