Impact of a kraft pulp and paper mill effluent on phytoplankton and macroinvertebrates in River Nzoia, Kenya
Water Quality Research Journal of Canada
Department of Biological Science, Moi University, Box 1125, Eldoret, Kenya; Department of Fisheries Aquatic Science, Moi University, Box 1125, Eldoret, Kenya; Department of Forestry and Wood Science, Moi University, Box 1125, Eldoret, Kenya; Department of Technology Education, Moi University, Box 1125, Eldoret, Kenya
Phytoplankton and macroinvertebrate assemblages were used to assess the impact of a kraft pulp and paper mill effluent in Kenya, on River Nzoia downstream of the discharge point in relation to changes in water quality during May to June and November 2008 (rainy and dry seasons, respectively). Total phosphorus concentration increased from 0.027 mg·L-1 upstream to 0.04 mg·L-1 downstream. Ammonia nitrogen (NH3-N) concentration was 0.51 mg·L-1 upstream and 0.86 mg·L-1 downstream. Nitrate concentration stood at 1.18 mg·L-1 upstream compared with the 2.23 mg·L-1 downstream. The pH changed from 4.5 to 5.0 upstream to 5.5 to 6.0 downstream, while DO increased from 6.57 to 7.03 mg·L-1 downstream. The BOD5 (biochemical oxygen demand after five days) values remained almost unchanged from 4.63 mg·L-1 upstream to 4.67 mg·L-1 downstream. Taxon composition of phytoplankton and macroinvertebrates correlated with adverse environmental gradients resulting from the mill's effluent discharge. Overall, there was a shift in composition and abundance of both phytoplankton and macroinvertebrates, with the downstream site recording high numbers of tolerant taxa (i.e., Microcystis sp. and Chironomus sp.). It was recommended that water quality monitoring with effluents of this nature be done using a combination of chemical analysis and biological indicators such as phytoplankton and macroinvertebrates. © 2010, CAWQ.
Ammonia nitrogen; Biological indicators; Biomonitoring; Chironomus; Dry seasons; Effluent discharge; Environmental gradient; Macroinvertebrate assemblage; Macroinvertebrates; Microcystis; Nitrate concentration; Pulp and paper; Pulp and paper mill effluents; Total phosphorus; Water quality monitoring; Algae control; Biochemical oxygen demand; Chemical analysis; Effluents; Indicators (chemical); Kraft process; Kraft pulp; Nutrients; Oxygen; Paper; Paper and pulp mills; Papermaking machinery; Phosphorus; Phytoplankton; Pollution; River pollution; Water quality; Rivers; abundance; bioindicator; biomonitoring; chemical analysis; chemical pollutant; dissolved oxygen; dose-response relationship; environmental gradient; industrial waste; macroinvertebrate; nitrate; pH; phytoplankton; pollution exposure; pulp and paper industry; water quality; Algae; Bod; Chemical Analysis; Effluents; Kenya; Kraft Pulps; Nutrients; Oxygen; Paper; Paper Making; Ph; Pollution; Rivers; Water Quality; Kenya; Nzoia River; Chironomus sp.; Microcystis; Microcystis sp.