Effect of kombolcha textile factory effluent on soil, vegetables and leyole river, north east Ethiopia

Abstract

Background:-Textile industries produce huge amount of effluents which is discharged to surface water bodies without proper treatment. Toxic heavy metals are released from textile industry effluents in to water, soil which are quite dangerous. Objective: - To assess the effects of kombolcha textile factory effluent on soil, vegetables and “Leyole” river.. Method:-The study was conducted in Kombolcha textile factory in 2018 by using cross sectional study design. A total of 28 samples were collected from effluent, river, sediments, vegetables and soils for assessing physicochemical, heavy metals and macroinvertebrate as bio- indicators. Analysis was done by using standard guideline of American Public Health Association 2012.Heavy metals were analyzed by using Flame Atomic Absorption Spectrometric. Macroinvertebrate metrics were calculated to assess the level of pollution in the stream. SPSS version 20 and MS excel software were employed for statistical analysis. Mann Whitney statistics were carried out to assess the significance difference between sampling point. Result:-The average concentration of Pb, Cd, Cr and Cu in soil and vegetable sample were 29.1, 1.63, 39.739.93 mg/l and 14.2, 1.09, 13.3 and 3.68 mg/kg respectively. The concentration of all investigated heavy metals except Pb in sediment was lower than international standard safe limits. The concentration of most physicochemical and heavy metal concentration were higher than the standards set by national and international agencies. A total of 1765 macro invertebrates belonging to 17 families and 7 orders were collected. The most abundant orders were Diptera with the value of 1079 (61.2%), Ephemeroptera 393(22.2%), Odonata 105(1.95%) and Hemiptera 99(5.6%) which were represented by13 families. The physicochemical and heavy metals in river showed great variation between sampling sites. Hilsenhoff family-level biotic index, percent Diptera, was higher at the most downstream site. Conclusion:-Highest accumulations of heavy metals were present in soils while lowest concentration was found in the river. Most physicochemical parameters of effluents and stream in the downstream were higher than the standards set by different authorized agencies. Most of tolerant macroinvertebrate were prevalent in the downstream while sensitive were more prevalent in the upstream. So the efficiency of the treatment plant should be improved.