Abstract
The water quality of Chole River was assessed based oninsitu measurements and laboratory analyses of water and benthic macroinvertebrates samples collected for three rounds from January - April, 2017 once every two months from three sites coded S1, S2 and S3 using standard procedures. Laboratory analyses of benthic macroinvertebrates samples yielded5712 specimens belonging to 26 families and 9 Orders. Percentage of sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera) (%EPT), Shannon diversity (H’), ETHbios score, Average Score Per Taxon and family richness decreased with increasing level of impacts from S1 through S3 to S2 in contrast to percentage of the tolerant Chironomidae (%Chiro.), percentage of dominant taxon (%DT) and Hilsonhoff’s Family Biotic Index (H-FBI).Mean %EPT was maximum at S1 (77.7%), followed by S3 (16.4%) and lowest at S2 (9.3%) whereas red Chironomidae dominated at S2 (84.6%) and S3 (91.8%). Family richness was maximum at S1 (25) and minimum at S2 (22). The lowest dissolved oxygen (4.29±1.85 mg/l) and maximum total phosphorus (6.09 ± 0.09) were determined at S2indicating organic and detergent pollutions, respectively. Electrical conductivity (609 ±169), Ammonium Nitrogen (0.091 ±0.067mg/l), Nitrate nitrogen (NO 3 - N) and (2.02 ± 0.141mg/l) picked at S3and remained relatively higher at S2.The heavy solid and liquid wastes loaded from Ambo University campus at S2 and common stressors at S3 including solid waste disposal, cattle watering, bathing, washing clothes and car washing might be responsible for the spatial variation in benthic macroinvertebrates indices/metrics and physicochemical parameterswhich indicateddeterioration in the water quality of Chole River at downstream sites. Keywords: Biomonitoring , Ethiopia, macroinvertebrates, physicochemical parameters, Water Quality DOI: 10.7176/JRDM/73-02 Publication date: February 28 th 2021
Highlights
Environmental pollution in general and pollution of flowing waters in particular has become a key focus of concern all over the world.Despite humanity’s reliance on flowing waterrapid urbanization, industrialization and the expansion of agriculture have severely degraded thequality of rivers worldwide, diminishing their ability to provide valuable ecosystem services and driving species to extinction.rivers in underdeveloped and developing countries are widely used as waste disposal sites for domestic and industrial wastes
Benthic macroinvertebrates have proved to be excellent indicators for the quality of freshwater stream habitats (Rosenberg and Resh, 1993; Mandavillae, 2002).They are widely used as bio-indicator in wadeable waters because they have generally limited mobility, quite easy to sample, well established sampling techniques, and there is a diversity of forms that ensures a wide range of sensitivities to changes in water quality (Hellawell, 1986; Abel, 1989)
Distribution and Abundance of Benthic Macroinvertebrates A total of 5712 specimens of macroinvertebrates belonging to 26 Families and 9 Orders i. e
Summary
Environmental pollution in general and pollution of flowing waters in particular has become a key focus of concern all over the world.Despite humanity’s reliance on flowing waterrapid urbanization, industrialization and the expansion of agriculture have severely degraded thequality of rivers worldwide, diminishing their ability to provide valuable ecosystem services and driving species to extinction.rivers in underdeveloped and developing countries are widely used as waste disposal sites for domestic and industrial wastes. Anthropogenic activities may alter the physical, chemical, or biological processes associated with water resources and modify the resident community (Karr, 1991).Though physicochemical and bacteriological measurements commonly form the basis of river monitoring, they cannot reflect the integration of numerous environmental factors for their instantaneous nature (Li et al, 2010) Because they focus on living organisms whose very existence represents the integration of conditions around them biological evaluations can diagnose chemical, physical, and biological impacts as well as their cumulative effects (Karr and Chu, 1997).The use of biological methods is based on the straightforward premise that living organisms are the ultimate indicators of environmental quality. The use of macroinvertebrates as indicators of environmental change in Ethiopia dates back to the 1980s (e.g., Harrison and Hynes, 1988; TesfayeBerheet al., 1989), with a renewed interest in recent years following the advent of multimetric assessment methods
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