Spatial and temporal variation of water quality and macroinvertebrate assemblages along Kico stream Kakira, Jinja-Uganda.

Abstract

In Uganda, there is increased effluent discharge into streams flowing near different industrial establishments. Effluent discharge into streams poses a great threat to different stream components and the communities dependant on such streams. However, such impact for streams like Kico is less understood in Uganda. This study therefore assessed the spatial and temporal variation of physicochemical parameters of water and ii) composition and abundance of macroinvertebrates along Kico stream so as to provide baseline information for its future conservation and sustainable utilisation. This study undertook a quantitative research approach with data collected from four purposively selected sample sites over two different seasons. These included; site 1 (upstream with less anthropogenic pressures), site 2 (after Wandago intercept; local distilleries characterised by distillery effluent discharge), site 3 (within Kakira sugar works with significant industry effluent discharge) and site 4 (where Kico stream discharges into River Nile between Kasambira swamp and River Nile). Some parameters were measured in-situ whereas others were analysed in the laboratory. The macroinvertebrates were identified following a macroinvertebrate identification guide. Water quality analysis was performed according to Standard Methods for the Examination of Water and Wastewater. The findings from the study revealed that apart from pH and electrical conductivity (EC), other physicochemical parameters of water significantly differed along the stream and between seasons (p < 0.05). For instance, pH at site 1 was 5.95 while at site 2 was 5.90, the pH values slightly increased at site 3 and site 4 with the respective values of 6.1 and 6.2. Further, 1,352 macroinvertebrate individuals belonging to 25 families, 06 orders and 03 classes were identified. Macroinvertebrates significantly varied (p < 0.05) between sites and seasons with sites 2 and 3 majorly dominated by pollutant tolerant taxa. Site 1 had the highest relative species abundance. Thus, efforts need to be invested by concerned authorities to ensure that effluents discharged into Kico stream are effectively treated. This will protect the health of the stream through maintaining its good water quality thus ensuring survival, enhanced composition and abundance of different aquatic biodiversity. Further research is needed to ascertain the concentration of microbial contents (biological water studies), nutrient and heavy metal concentrations in water along Kico stream and over seasons under the current existing anthropogenic pressures so as to assess its suitability for domestic use and aquatic biodiversity conservation.