|Biomonitoring of the water quality in the river Warche (Belgium): impact of tributaries and sewage effluent|
Marneffe, Y.; Comblin, S.; Bussers, J.-C.; Thomé, J.-P. (1996). Biomonitoring of the water quality in the river Warche (Belgium): impact of tributaries and sewage effluent. Neth. J. Zool. 46(3-4): 337-350
In: Netherlands Journal of Zoology. E.J. Brill: Leiden. ISSN 0028-2960, more
|Authors|| || Top |
- Marneffe, Y.
- Comblin, S.
- Bussers, J.-C., more
- Thomé, J.-P., more
Between March 1994 and March 1995, sampling campaigns were carried out each fortnight in order to determine the physical, chemical and biological quality of the water in the river Warche. Macroinvertebrate and rotifer biomonitoring (based on the global and Belgian biotic index and on the Sládecek index respectively) were used as bioindicators. These biotic indices were related to the main physical and chemical parameters monitored between the source and the town of Malmédy (i.e., a river length of 40 km). Important seasonal and longitudinal changes of physical, chemical and biological water quality occur. The deterioration of the water quality in the river Warche is obvious in two sectors of the river. Strong organic pollution and eutrophication were observed between the source and the sampling station located downstream of Büllingen. Indeed, along this sector, tributaries, sewage and dairy effluent flow into the Warche and induce significant increase of nitrate, nitrite, ammonium and phosphate concentrations. As a consequence, biotic indices decrease significantly downstream of Büllingen and the most abundant rotifer species are clearly eutrophic indicators. Another important decrease of water quality was observed downstream of an important paper mill effluent which induces a significant increase of temperature and of nitrite and sulphate concentrations. The presence of two lakes along the Warche course induces downstream either a restoration of the water quality during a mixing period of the lake or an increase of ammonium and phosphate concentrations after water stratification as a result of a temperature gradient in the lake.