Anthropogenic and seasonal influences on the dynamics of selected heavy metals in Lake Naivasha, Kenya

Joseph Nyingi Kamau, Anthony Gachanja, Catherine Ngila, Johnson Michael Kazungu, Mingzhe Zhai

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Lake Naivasha is a freshwater lake in the Eastern Rift Valley of Kenya (0°45′S and 36°20′E). It has no surface outlet and is perceived to be under anthropogenic stress. Being situated at the basin of the rift valley, the lake acts as a sink for wastes from the town of Naivasha and the surrounding horticultural industry. Flux experiments were conducted to investigate the dynamics of heavy metals between the sediment-water interface in Lake Naivasha. In situ benthic flux experiments were conducted at two sites, one near the municipal wastewater inflow to the lake (site SS), and one at the papyrus field near the horticultural farms (site SH). Sediment samples from the exposed riparian land were collected during the dry season after the lake has receded, and the fluxes of selected metals were determined in the laboratory under simulated conditions. Aluminium in situ benthic flux at site SS averaged 7 mmol m-2h-1, and was correlated positively with pH (Pearson correlation coefficient (r) = 0.89). While the in situ benthic flux of aluminium at site SH averaged 1 mmol m-2h-1. In situ benthic fluxes of copper and manganese were predominantly positive at site SS, but not at site SH. The papyrus field at site SH played an important role in buffering of the lake in regard to the selected metals investigated in this study. Redox-sensitive metals were precipitated in the benthic flux experiment for this site.

Original languageEnglish
Pages (from-to)145-154
Number of pages10
JournalLakes and Reservoirs: Research and Management
Volume13
Issue number2
DOIs
Publication statusPublished - Jun 2008
Externally publishedYes

Keywords

  • Aluminium
  • Benthicflux
  • Copper
  • Freshwater
  • Lake Naivasha
  • Manganese
  • Sediment
  • Zinc

ASJC Scopus subject areas

  • Water Science and Technology

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