No abstract

Cassava mill effluents are discharged into the environment by smallholder cassava processor in rural communities in the Niger Delta region of Nigeria. Cassava mill effluents are known to induce toxicity in some biodiversity such as livestock (sheep, goat), vegetation, microorganisms and fisheries. This study evaluated the pollution load indices of heavy metals in cassava mill effluents contaminated soil in rural community in the Niger Delta region of Nigeria. Secondary data from cassava mill effluents soil were used for the study. The data were classified based on seasons. The pollution load was calculated following standard protocol. Nine pollution indices were considered including Contamination factor (CF), Degree of contamination (CD), Pollution load index (PLI), Pollution index (PI), Sum of pollution index (SPI), Pollution index/ Contamination Index (PI/CI), Metal pollution Index (MPI), Average Pollution Index (API) and Nemerow integrated pollution index (NIPI). In few instance that some heavy metals was not detected, 50% of mean detected individual metals were considered for the location that the metals were not detected. Geometric (BGM) and median mean (BMM) were considered for the background scenarios except for API and PI/CI in which median mean was used. The pollution load resulting from these heavy metals viz: Fe, Cr, Zn, Cu, Co, Ni, Mn, Pb and Cd revealed that CF and CD had low to moderate contamination level in both seasons apart from Pb that had considerable pollution in one of the locations for wet season, PLI were within no pollution to moderate pollution, PI were also within no pollution to low pollution level and NIPI were within warning line of pollution to low level of pollution for dry season, and warning line of pollution to high pollution in wet season. MPI, PI/CI and API showed slight pollution. The findings of this study also showed that cassava processing by smallholder in rural communities in the Niger Delta is slightly contributing to heavy metals pollution is receiving soil which varies according to seasons. Furthermore, age and heavy metal content in the cassava tuber and quantity of cassava processed in each mill and other anthropogenic activities could account for difference in pollution among the various locations, while runoff resulting from rainfall could account for the seasonal influence.

Cassava is majorly processed into gari by smallholders in Southern Nigeria. During processing, large volume of effluents are produced in the pressing stage of cassava tuber processing. The cassava mill effluents are discharged into the soil directly and it drain into nearby pits, surface water, and canals without treatment. Cassava mill effluents is known to alter the receiving soil and water characteristics and affects the biota in such environments, such as fishes (water), domestic animals, and vegetation (soil). This study investigated the potential of Saccharomyces cerevisiae to be used for the treatment of some physicochemical properties of cassava mill effluents. S. cerevisiae was isolated from palm wine and identified based on conventional microbiological techniques, viz. morphological, cultural, and physiological/biochemical characteristics. The S. cerevisiae was inoculated into sterile cassava mill effluents and incubated for 15 days. Triplicate samples were withdrawn from the setup after the fifth day of treatment. Portable equipment was used to analyze the in-situ parameters, viz. total dissolved solids (TDS), pH, dissolved oxygen (DO), conductivity, salinity, and turbidity. Anions (nitrate, sulphate, and phosphate) and chemical oxygen demand (COD) were analyzed using spectrophotometric and open reflux methods respectively. Results showed a decline of 37.62%, 22.96%, 29.63%, 20.49%, 21.44%, 1.70%, 53.48%, 68.00%, 100%, and 74.48% in pH, conductivity, DO, TDS, salinity, sulphate, nitrate, phosphate, and COD levels respectively, and elevation of 17.17% by turbidity. The study showed that S. cerevisiae could be used for the treatment of cassava mill effluents prior to being discharged into the environment so as to reduce the pollution or contamination and toxicity levels.

Malaria is a major cause of morbidity and mortality especially in the Sub-Sahara Africa, where significant deaths occur annually. Malaria is majorly caused by a protozoan of the genus Plasmodium which is transmitted by female Anopheles mosquito, an iniquitous dipteran fly. Malaria is endemic in Nigeria as such over 95% are at risk. The prevalence of malaria is depended on certain factors including medical conditions, environment/season and human status viz: pregnancy, blood group, Rhesus factor, age, gender and educational status. As such the predisposing factor of high prevalence of malaria within a location/locality needed to be ascertained in order to effectively manage the infection.

Cassava mill effluent (CME) is generated during cassava processing into cassava flake or gari. The effluents affects the quality of the receiving environment such soil. It is could affect domestic animals such as goat and sheep when they ingest it, and retard normal growth and productivity of plants in the affected soil. This study evaluated amino acid and proximate composition of Saccharomyces cerevisiae cultivated in cassava mill effluents. S. cerevisiae used in this study was isolated from palm wine based on cultural, morphological, and physiological/biochemical characteristics. 10 ml of S. cerevisiae broth was inoculated into 100ml of sterile cassava mill effluents filtered with double muslin cloth. The medium was shaken intermittently between 7.00 to 19.00 hours' time interval. The medium was decanted and subsequently filtered using Whatman filter paper. The resultant biomass was washed with distilled water and re-filtered. The sludge/biomass recovered were oven dried. Amino acid and proximate composition of the yeast biomass produced was analyzed using spectrophotometer. Proximate composition was also analyzed following standard procedure. Result showed that the total essential amino acid (40.88 g/100 g) was slightly higher than the Food and Agricultural Organization/World Health Organization (FAO/WHO) standard for feed use. While the total non-essential amino acid (21.56 g/100 g) was lower than FAO/WHO limits. Mean proximate composition was 17.01% (crude protein), 7.34% (ash), 56.40% (carbohydrate) and 407.13 kcal/100 g (calorific value/energy content). The findings of this study showed that during fermentation of cassava mill effluents with S. cerevisiae an appreciable amount protein is enriched considering the fact that the substrate is a waste.