Bioaccumulation of trace metals in biota (algae and chironomids) from Kenyan saline lakes (Bogoria and Nakuru): evaluation and verification of two compartment toxicokinetic models

This study aimed to assess the suitability of aquatic biota from some Kenyan Saline lakes as biomonitors of trace metals. The use of compartment models as predictive tools in assessment environmental quality was also evaluated. The test organisms (Algae Arthrospira fusiformis and chironomids Lepotochironomous deribae) exhibited organism dependent and element specific metal uptake and elimination trends. Metal uptake in algae was fast (within hours) but in chironomids it was within days. Copper unlike Cd, Pb and Zn had a more rapid uptake rate in algae. Cd and Cu elements though, had more reliable models. Model reproducibility was element specific and ecosystem dependent. Concentration dependent metal uptake trends (CDMET) were inconsistent except for Cu in Nakuru algae. A higher predictability chance for metal uptake trends was demonstrated using model parameters and data obtained from the same lake. For chironomids reliable models were obtained for all elements Cd, Cu, Pb and Zn. CDMET were more distinct and consistent. The Zn element had the most predictable uptake trend. In algae it was Cu. Compartment models can be used to clarify biological and related environmental bioaccumulation occurrences. Lake Bogoria has a higher capacity to withstand metal pollution (due to reduced metal bioavailability) as compared to L. Nakuru. However L. Nakuru has a higher contamination potential due to its location near Nakuru town. Metal concentrations in Nakuru and Bogoria sediments are still within relevant geological background levels. Studies towards the next steps in calibration of the relevant organisms as biomonitors of the specific ecosystems are needed.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Oldenburg

Year

2007

Author dc:creator

• Muohi, Ann Wairimu

• [Keine Schlagwörter von Autor/in vergeben.]

Repository record source_url

http://oops.uni-oldenburg.de/37

OAI identifier oai:identifier

oai:oops.uni-oldenburg.de:37