Biological water quality assessment in the degraded Mutara rangelands, northeastern Rwanda

• Published in: Environmental monitoring and assessment Vol. 191; no. 3; pp. 139 - 13
• Main Authors: Dusabe, Marie-Claire, Wronski, Torsten, Gomes-Silva, Guilherme, Plath, Martin, Albrecht, Christian, Apio, Ann
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2019; Springer Nature B.V
• Subjects: Anthropogenic factors; Atmospheric Protection/Air Quality Control/Air Pollution; Drinking water; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental monitoring; Environmental science; Equipment costs; Grasslands; Human influences; Human populations; Land use; Livestock; Macroinvertebrates; Monitoring/Environmental Analysis; Pollution effects; Pollution monitoring; Public health; Quality assessment; Quality control; Rangelands; Refuges; Rivers; Sanitation; Surveys; Training; War; Wastewater; Water pollution; Water quality; Water quality assessments; Zoobenthos; Rwanda; River pollution; Akagera ecosystem; Water safety; TARISS; Macrozoobenthos; Stream invertebrates
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-019-7226-5

Rwanda is a heavily overpopulated country that also suffers from overstocking with livestock, especially following the return of war refuges after the civil war (1991–1995). At present, approximately 20% of the human population in Nyagatare District in northeastern Rwanda has no access to clean drinking water and sanitation. We used a biotic index based on the presence of selected families of aquatic macroinvertebrates, derived from the “Tanzania River Scoring System” (TARISS), to assess water quality at N  = 55 sites in the Mutara grasslands in Nyagatare District. Poor water quality became evident across most sampling sites both in the Muvumba (mean ± SE TARISS score 5.25 ± 0.10) and Karangazi Rivers (4.79 ± 0.12). Using a general linear model, we asked whether direct effects of land use forms and input of anthropogenic wastewater have an impact on water quality. Our results found no immediate effects of both forms of disturbance/pollution, probably because overall water quality was already poor. Our study is intended to serve as a starting point for continuous monitoring of water quality in the Mutara rangelands in NE Rwanda. The method applied here is cost-efficient, requires only basic equipment, and training local students to apply this technique can provide a solid basis for its implementation in future surveys related to public health.