Genotoxicity Screening of Industrial Effluents using Onion bulbs (<i>Allium cepa L.</i>)

Abstract

ABSTRACT:The potential cytotoxicity and genotoxicity of three industrial wastewaters (brewery, rubber and bottling) in Benin metropolis using the Allium cepa test were investigated. A series of five small onion bulbs were cultivated in 0.01, 0.1, 1, and 10% of the wastewaters (v/v) and after 48 hours, one root tip from each bulb was harvested and processed for cytological studies by the aceto-orcein squash technique. At 72h, their cytotoxic effects on the root tips showed strong growth retardation in high concentrations of all the wastewaters. Compared to the control, treatment with the wastewaters resulted in root growth inhibition with EC50 values of 35, 50 and 62% for bottling, rubber and brewery effluents respectively, and decrease in mitotic index with increasing concentration for all samples and these were statistically significant (p<0.05). Chromosomal aberrations induced in the onion root tip cells were mostly sticky chromosomes and bridges. Chromosomes with disturbed spindles and fragments were also present in appreciable amounts. Based on the EC50 values, the bottling wastewater was most toxic, followed by rubber effluent while effluents from the brewery were least toxic. The findings in this study indicate that there are toxic chemicals present in the wastewaters which are responsible for the observed genotoxic effects on the onion root tip cells. The study also reveals that the Allium test is a useful and reliable tool for the genotoxicity screening of industrial effluents which could be employed by environmental managers before these effluents are finally discharged into the environment. @JASEM

Toxicity Evaluation and Cytogenetic Screening of Process Water Using a Plant Bioassay

“…The concentrationdependent decrease in mitotic index and increase in the number of aberrant cells of processed water in this study is an indication of toxicity. This is in agreement with observations in earlier related studies (El-shahaby et al, 2003;Olorunfemi et al 2011;. It can be inferred that the inhibitory effects of the tested water sample on root growth and cell proliferation in A. cepa could have been by inhibition of DNA synthesis at Sphase (Sudhakar, et al, 2001;Glinska et al, 2007), complete destruction of metabolic activities that prevented the cell from entering mitosis (Metin and Burun, 2010) or disturbances of cell cycle or chromatin materials (Glinska et al, 2007).…”

“…Toxicity endpoints obtained with this plant assay compare well with animal and fish lethality bioassays in their relative sensitivity toward environmental pollutants (Grover and Kaur, 1999;El-Shahaby et al, 2003;Junior et al, 2007;Abdel-Migid et al, 2007;Sık et al, 2009, Olorunfemi et al 2011. In the light of the above, this study was undertaken to ascertain and blind, the mutagenicity of process water on the chromosomes of A. cepa.…”

Induction of chromosome aberrations inAllium cepaL. root tips on exposure to ballast water

“…The Allium test has been accepted as an excellent first-tier indicator for safety evaluation of cyto-genotoxicity monitoring of chemicals, drinking water, wastewaters and complex mixtures (Fiskesjö 1985). Recent studies using the Allium cepa test include genotoxicity testing of phenoxy herbicide (Yildiz and Evrim (Olorunfemi et al 2011a(Olorunfemi et al , 2011b. The objective of this study therefore is to investigate the effects of ballast water on root growth, mitotic index, chromosome aberrations and micronucleus formation in the root meristem cells of Allium cepa L. Data obtained from the study would reveal the extent of pollution and the possible health implications of the wastewater, and thereby assist policy makers and regulatory agencies insist on proper treatment before discharge into the environment.…”

Comparative physicochemical and genotoxicity assessments of textile mill company effluent and local tie-and-dye textile wastewater

“…Lead has been implicated in enzyme inhibition, mutation, and chromosomal irregularities (Johnson, 1998). Studies have pointed out that there is a good correlation between chromosome abnormalities and mutagenic activity found in root-tip systems and those found in mammalian cell systems (Majer et al, 2005;Olorunfemi et al, 2011). Therefore, the effluents emanating from the local Adire (Tie-and-dye) textile business and the corporate textile mill company are potentially genotoxic to plant, animals and humans.…”

“…(Tie-and-dye) effluents: The genotoxicity assessment of textile mill and Adire (Tie-and-dye) effluents was carried out using the Allium assay test. Allium assay test was adapted from Fiskesjo (1993), Bakare et al (2009) and Olorunfemi et al (2011). The outer scales and brownish bottom plate of sun dried onion bulbs were carefully removed, leaving the ring of primordial root intact.…”