Biological indicators integration with physicochemical parameters for water quality assessment of Lake Haramaya, Eastern Ethiopia

Ethiopian lakes are important to local livelihoods and the country’s economy, but increasing demand and environmental degradation are putting them in danger. This might have detrimental impacts primarily on the local economy, ecology, and ecological balance. Thus, this study’s goal is to assess Lake Haramaya’s water quality by integrating biological and physicochemical parameters. Macroinvertebrates and water samples were collected to offer a quantitative and qualitative assessment of the community composition at each sampling location. Locations for sampling were selected, taking into account several aspects. Samples were collected near onshore parts of the lake at each respective selected sampling site. This study shows that turbidity and phosphate exceed the recommended levels for freshwater lakes. The highest relative abundance of Gastropoda in this study is due to its high tolerance to pollutants. The Biological Monitoring Working Party (BMWP) identified macroinvertebrate families that indicate that the lake water is poor; however, the Average Score Per Taxon (ASPT) shows the water quality evaluation is good. This may be because the sample population of Lake Haramaya has a very moderate level of diversity; only more families that are highly tolerant of pollution were present, which could have caused the final score of the BMWP to be relatively lower, yet the ASPT index is relatively higher. Overall, the present study confirmed that Lake Haramaya has been contaminated and is no longer pollution-free. Therefore, to give comprehensive information, using other biotic indexes and physicochemical parameters in combination may also be more important for future studies.