Toxicity evaluation of waste effluent from cassava-processing factory in Lagos state, Nigeria using the <i>Allium cepa</i> assay

Abstract

Mutagenic and genotoxic effects of cassava wastewater (CWW) were investigated by assay of Allium cepa root meristematic cells. The physicochemical parameters of the wastewater samples were also determined. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the CWW and distilled water was used as a negative control. After 72 h, the root tips from the treated bulb were processed for cytological studies by orcein squash technique. The mean lengths of root bundles were obtained and effective concentration (EC) values calculated. The cytotoxic effects on the onion root tips showed strong growth retardation at high concentrations of the effluent with EC value of 5.67%. The mitotic index (MI) 50 rapidly decreased with increasing effluent concentration compared to control. There was significant increase in frequency of chromosome aberrations (stickiness, c-mitosis, vagrant, bridged fragment, binuclei, multipolar anaphase, attached chromosome and laggard chromosome) in root tip meristem cells of Allium cepa at all tested concentrations. At lower concentrations (0.005%), binuclei, (0.5%), vagrant chromosome and (1.0%), bridged fragment were the most common aberrations observed while at higher concentrations, (100 %), c-mitosis, vagrant and bridged fragment were the typical aberrations observed. The results indicate that the effluent samples collected were highly mutagenic. The results of physicochemical analysis revealed that the concentrations of some parameters (turbidity, chemical oxygen demand (COD), biological oxygen demand (BOD), conductivity, total dissolved solid (TDS), total suspended solid (TSS), sulphate, nitrate, phosphate and metals-copper, cobalt, chromium, iron, manganese, magnesium, nickel, cadmium, lead, sodium, potassium and calcium) were above the maximum permissible limit set by world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The findings indicate that the substances contained in the cassava effluents may be toxic to living organisms and may pollute the environment if untreated.

Assessment of Cytotoxicity and Genotoxicity Potential of Effluents from Bahir Dar Tannery Using Allium cepa

“…Most of the aberrations in the current study were sticky at metaphase and the chromosomes were condensed at the equatorial plate. Similar reports were given by Soodan et al [42], Olorunfemi et al [38], and Ogunyemi et al [43]. In this study, the opposite poles of chromatids were tightly linked to each other during anaphase forming chromosome bridges resulting from adherence and may persist until telophase.…”

“…is aberration was also similar to the result reported by Soodan et al [42]. e lagging chromosomes resulted due to failure of the chromosomes to get attached to the spindle fiber and to move to either of the two poles; similar results were observed by Ogunyemi et al [43] and Nefic et al [44].…”

“…In this study, the opposite poles of chromatids were tightly linked to each other during anaphase forming chromosome bridges resulting from adherence and may persist until telophase. is was also observed in anaphase stages reported by Soodan et al [42], Olorunfemi et al [38], and Ogunyemi et al [43].…”

“…All these alterations in the morphology of nuclei in the cell indicated that tannery effluent has a toxic effect on the gene of the model plant (Allium cepa) and this can be used as a genotoxicity measurement. ese nucleus changes in the micronucleated cells were observed in studies reported by Ogunyemi et al [43] and Nefic et al [44]. e presence of micronucleated cells indicates an aneugenic and clastogenic activity, because, according to Fenech [46], micronucleus can be derived from acentric fragments, which indicates clastogenic activity, or from entire chromosomes, which indicates an aneugenic activity.…”

Assessment of leachate contamination potential of landfills in Ibadan, Nigeria

“…The mean values obtained from the physicochemical and microbiological examination of the leachate samples compared with the WHO wastewater discharge limits are in Table 1 All parameters are measured in mg/L, save for pH (no unit) and Total Coliform/ Fungal Count (CFUs/ml); concentrations values that do not conform to the stipulated standard are italicized; *a indicates FEPA permissible limit for discharge into surface water as adapted from Salami and Susu (2019). (Salami and Susu, 2019) and pH value of 8.97 observed in Sarbah landfill in Accra-Ghana (Sackey and Meizah, 2015); though in sharp contrast with the 5.11 pH value recorded in Olososun landfill in Lagos (Ogunyemi et al, 2018). The alkaline pH observed is expected because of the over two decade old landfills.…”