Determination of Heavy Metals Contamination of the Environment Around Ziway Floriculture Industry

摘要

The aim of this study was to determine the level of environmental pollution by selected heavy metals in soil, water and vegetables around floriculture industry. The level of the selected heavy metals in soil, water and vegetables were analysed by Flame Atomic Absorption spectroscopy. The detected range of the heavy metals in soil sample collected at different distances from the targeted floriculture area were Cd(ND- 0.10± 0.002), Pb(1.78± 0.003-7.01±0.007), Cr(7.00±0.006 to 14.2±0.003), Ni(7.22±0.006 to 13.76± 0.003), Co(3.12±0.025 to 5.71±0.003), Cu(2.22±0.003-5.89±0.002), Zn(56.2±0.006-70.9 ± 0.003) mg/kg in top soil and subsoil were Cd(ND to 0.10±0.004), Pb(1.7±0.005 to 2±0.015), Cr(4.03±0.002 to 13.8±0.01), Ni(8.39±0.005-10.0±0.003), Co(3.0±0.001-6.95± 0.003), Cu(2.0± 0.002-4.60±0.002), Zn(40.75±0.02-67.9±0.01). The level of metals Cd (0.258±0.0-0.61±0.001), Pb(0.053±0.002 -1.67±0.002), Cr(1.20±0.005-3.01±0.002), Ni(17.15±0.013-34.46±0.009), Cu(1.61±0.002-3.29±0.030), Zn (33.33±0.004-40.53±0.006), Co (0.13± 0.003-1.39±0.003)mg/kg in vegetable .Onion accumulate metals than tomato and cabbage Oniontomatocabbage. Concentration of metals in Lake ziway were 0.01±0.001, 0.06± 0.001, 0.012±0.12, 0.117±0.02, and 0.05±0.01mg/L for Ni, Cr, Cu, Zn and Co respectively. Pb and Cd were below the limit of detection. The measured physico chemical parameters in soil sample ranged pH (7.49-8.92) Electrical Conductivity (0.786± 0.010-2.851±0.01).the pH of water was 8.78±0.001and its EC was 0.626±0.003.The level of heavy metals in soil samples was found to increases as sampling distance from the factory decreases .This study indicates that all of the metals are concentrated on the surface soil, and decreased in the lower part of the soil, this is due to reflect their mobility and physical properties of soil and its alkaline pH values.