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Soil and sediment samples collected from 0.1 to 25 km away from a heavily contaminated site at Vikuge farm in Coast region were extracted, cleaned by GPC and analyzed using GC-ECD and GC-MS. Ten compounds namely p,p’-DDT, o,p’-DDT, p,p’-DDE, o,p’-DDE, p,p’-DDD, o,p’-DDD, pentachloroanisole, a-HCH, b-HCH and g-HCH were detected in the samples. In general, contaminants during this round of sampling were widespread. The compounds o,p’- and p,p’-DDT, DDD and DDE were detected in 64.3% - 100% of the samples. Pentachloroanisole was detected in 95.5% of the soil and 50% of the sediment samples, while for the HCH isomers, the highest frequency was for b-HCH (57.1%) in sediments. The concentrations of total DDT were up to 534 ng/g dry weight (dw) in soil and 1945 ng/g dw in sediments. The highest concentrations for total HCH were 3.8 ng/g dw in soil and 24.6 ng/g dw in sediments. The very strong positive correlations in the concentrations of the detected compounds suggest a common source. The low DDE/DDT ratios (0.01 - 0.83) in all but one sample indicate input of significantly non-degraded DDT from the source. The high DDE/DDT ratio (1.35) in one soil sample indicates significant degradation. The low a-HCH/g- HCH ratios in the samples indicate inputs of lindane. There is an urgent need for remedial actions to solve the problem at the source. |
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