The objective of this study was to evaluate the mutagenic potentialities of two samples of water from different sources namely: raw sewage, treated sewage. Genotoxicity test was conducted using two varieties of Vicia faba var; Giza 3 and var. Giza Blanca). Several endpoints were used to estimate the mutagenic activity in Vicia cells such as: 1-mitotic activity 2-nuclear abnormalities and 3-chromosomal aberrations. Chemical analysis revealed the inefficient treatment of sewage where, many elements increased after secondary treatment, and even those elements which decreased did not reach the safe limits for use. Genotoxicity test exhibited change in mitotic activity with all water samples, either by decrease in the mitotic index in Vicia var. G. 3 or increase in case of Vicia var. G. Blanca. Many types of chromosomal aberrations and nuclear irregularities were also produced after all treatments. The most frequent aberration was chromosome stickiness among different types of abnormalities such as: micronucleus, banded chromosomes, bridges, laggard chromosomes and ring chromosome. The higher percentage of chromosomal aberrations is exhibited by raw sewage. The current data demonstrated the occurrence of mutagenic compounds in sewage water after secondary treatment and this requires further treatment to remove them. Moreover, their application to irrigate agricultural land must be stopped because of the mutagenic effects of plants irrigated by such waters.
Key words: Sewage water, genotoxicity, Vicia test.
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