Evaluation of cycling patterns of dissolved oxygen in a tropical lake as an indicator of biodegradable organic pollution

• Published in: The Science of the total environment 1999-07, Vol.231 (2), p.145-158
• Main Authors: Ansa-Asare, O.D., Marr, I.L., Cresser, M.S.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biodegradation; Biodegradation, Environmental; Biological and medical sciences; Computer simulation; Continental surface waters; Cycling patterns; Dissolved oxygen; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; Environmental Monitoring; Exact sciences and technology; Fresh Water - analysis; Fresh water environment; Freshwater; Fundamental and applied biological sciences. Psychology; Ghana; Mathematical model; Mathematical models; Models, Theoretical; Natural water pollution; Oxygen - analysis; Pollution; Pollution indicator; Pollution, environment geology; Tropical Climate; Tropical lake; Water Pollution, Chemical - analysis; Water treatment and pollution
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/S0048-9697(99)00088-1

Dissolved oxygen cycling patterns in a tropical lake (Weija Lake) were shown to be useful as a potential indicator of biodegradable organic pollution, by dosing with liquid malt to give an additional organic burden of 2.5 and 5.0 mg l −1 TOC, and monitoring the DO values continuously for 140 h. These loadings were added to water columns (in tubes) suspended from a raft in a lake in south-east Ghana. The addition of organic pollution burden to the lake water produced two main effects: the mean DO value was lowered, and the amplitude of the DO cycle decreased as organic loading increased from 2.5 to 5.0 mg l −1 TOC. There was also an indication of heterotrophic respiration associated with organic inputs for the 5.0 mg l −1 added TOC suggesting a P/R ratio of well below 1.0. Taking the results of a DO cycling computer model together with those from the lake raft experiments, it can be concluded that dissolved oxygen cycles can be a good indicator of biodegradable organic pollution load.