Toxicity of cassava wastewater effluents to African catfish: <i>Clarias gariepinus</i> (Burchell, 1822)

Abstract

The relative lethal and sublethal toxicity of cassava wastewater effluents from a local food factory were investigated on Clarias gariepinus fingerlings using a renewable static bioassay. The physico-chemical characteristics of the cassava wastewater effluents showed a number of deviations from the standards of the Federal Environmental Protection Agency (FEPA) on the guidelines for effluent discharges. Considering the pollutants of the effluent, cyanide (CN) is suspected to be primarily responsible for the toxicity, although synergistic effect of other pollutants cannot be ruled out. At each exposure, in the two tests, the test-organisms showed signs of serious stress, swimming pattern changed and mortality increased over relatively small increase in concentration. The LC50 for lethal and sublethal tests were 0.024 mg1 -1 and 0.0064 mg1 -1 , respectively. The differences observed in the mortalities and bioconcentration of metals in fish muscles of varying concentrations were significant (p<0.05). It is suggested that deposition of cassava wastewaters into aquatic environments may impair the natural population size while the consumption of fish from such environment is deleterious.

Toxicity Evaluation of Wastewater Treatment Plant of Textile Effluent Using Fish: Nile tilapia <i>Oreochromis niloticus</i>

“…namely: active. fatigue and collapse.This result was in line with the findings of Adewoye et al (2005) and Soni et al (2006) who reported that erratic behavioural responses of the test organisms were resulted from high concentration of toxicants found in the industrial effluent. As the authors reported that as the experiment progressed, erratic behavioural response of the test organisms was reduced, and eventually they stopped swimming.…”

Acute toxicity of synyhetic resin effluent to African Catfish, Clarias gariepinus [BURCHELL, 1822]

“…The synthetic resin effluent examined in this work was found to be high in total suspended solid (TSS), low biochemical oxygen demand (BOD), low dissolved oxygen (DO), low total dissolved solids (TDS) and high lead and cyanide content which shows the effluent to be toxic for discharge into the aquatic environment. The abnormalities observed prior to mortality is an indication of depleted oxygen content due to higher demand for oxygen, this corresponds to the findings of Adewoye et al, (2005) that the observed characteristics features may have resulted from the organic loads in the wastewater and to different concentrations of toxicants. The high degree of lead and cyanide found in the effluent may have contributed a significant synergistic effects which resulted in the breakdown of vital metabolic functions that led to high mortality observed especially in the highest concentrations and this corresponds to the discovery of Van-Dyk et al, (2007) that the harmful effects of heavy metals pollution of fish depend on the duration of the exposure (chronic or acute) and the concentration level of the specific metal.…”

“…The 24-h LC 50 value of neem leaf extract for Prochilodus lineatus was found to be 4.8gL −1 (Winkaler et al, 2007). Adewoye et al, (2005) noted that at 96-h LC 50 concentration, the fitness of the natural population of an aquatic environment would be relatively impaired and as the concentration increases, the mortality rate also increases. The 96h LC 50 of 0.355187mg/L implies that at this concentration of the effluent in the aquatic environment, half of the entire natural population will become dead.…”

Cassava: The Drought, War and Famine Crop in a Changing World

“…A problem with most of these methods is that beneficial nutrients, such as B vitamins (thiamine, riboflavin and niacin), β-carotene (a source of vitamin A) and vitamin C, can be leached out or destroyed, which reduces the already low nutritional value of cassava [33]. There is also evidence that waste water from cassava processing (e.g., for starch production) can be toxic to the environment, with significant toxicity in fish reported [124,125].…”