EVALUATION OF THE LEVELS OF TOTAL VOLATILE BASES AND TRIMETHYLEAMINE FORMED IN FISH STORED AT LOW TEMPERATURE

The levels of total volatile bases (TVB) and trimethylamine (TMA) formed in three species of saline water fish stored at - 4°C were investigated as indices of spoilage. The data showed that the concentration of TVB (mg/100g sample) in Tilapia spp. ranged from 19.40 – 61.00; Mugil cephalus 10.30 – 41.10 and Carassius auratus 12.50 – 66.7 during the maximum storage period of 20 days, while TMA levels (mg/100g sample) over the same storage period and conditions ranged from < 0.001 – 7.12 for Tilapia spp., < 0.001 – 6.45 for Mugil Cephalus and < 0.001 – 7.28 for Carassious auratus. The data showed that the concentration of TVB and TMA increased with increasing storage time. These data may be used in formulating appropriate food safety limits for consumption of refrigerated fresh fish products in Nigeria. KEY WORDS: Total volatile bases, Trimethyleamine, Food storage Bull. Chem. Soc. Ethiop. 2006, 20(1), 155-159

Desorption of Pb2+ and Cu2+ from Nipa palm (Nypa fruticans Wurmb) biomass

The desorption of Pb2+ and Cu2+ from Nypa frutican Wurmb biomass originally loaded with these two metals in a batch adsorption experiment was investigated using acidic, basic and neutral desorption solutions. The metal-loaded biomass was treated with 0.1 M HCl, 0.1 M NaOH and distilled water atvarying contact time. The data shows that desorption in all the reagent increased with increase in contact time, reaching 75.3 and 63.7% in acid reagent, 18.9 and 14.06% in basic reagent and 3.35 and 2.44% in distilled water for Pb2+ and Cu2+, respectively, at a contact time of 140 min. The desorption kinetic showed that the release constant, kdes, for both metal ion in acidic system was faster (6.3 x 102 and 7. 9 x 102 min-1 for Pb2+ and Cu2+) than other desorption reagents

Removal of Cu (II) and Zn (II) ions from wastewater by cassava (Manihot esculenta Cranz) waste biomass

The ability of cassava waste biomass (untreated and acid treated) to remove heavy metals (Cu(II) and Zn(II) ) from single-ion solution and wastewater was investigated. All experiments were conducted using 10mM solutions of mixed metal ions of CuSO4.5H2O and ZnCl2. The uptake capacities of the two metal ions tested on the untreated and acid treated cassava waste biomass were 71.3 and 85.2 mg/g for Cu(II), and 43.4 and 58.1 mg/g for Zn(II) in single-ion solution. For wastewater, the uptake capacities of untreated and acid treated biomass was found to be 40.1 and 59.7 mg/g for Cu(II), and 38.6 and 38.7 mg/g for Zn(II), respectively. Metal ion uptake capacities in wastewater were lower than in single-ion solution probably due to competition of metal ions of different sizes on available binding sites. Uptake capacities of these metal ions on the biomass surface increased with acid treatment. Equilibrium sorption studies showed that the extent of metal uptake was enhanced by chemically modifying the cassava waste biomass by thiolation. Cassava waste biomass saturated with metal ions shows remarkable ability for metal recovery by dilute acid treatment, and can be used repeatedly for removal of heavy metals in single-ion solution and in wastewater effluents. Key words: Wastewater, bioremediation, heavy metals, biosorption, cassava waste. African Journal of Biotechnology Vol.2(10) 2003: 360-36

Evaluation of Concentrations and Human Health Risk of Cu, Zn, Fe in Two Periwinkles Species from Three Local Government Areas, Bayelsa State, Nigeria.

This study has investigated the concentrations of Cu, Zn and Fe in P. aurita and T. fuscatus obtained from Bayelsa State, Nigeria and assessed the health risks associated with the consumption of these shellfishes. The concentrations of the metals in mg/kg dry wt basis mean + SD were Cu (57.0 + 4.0) Zn (63.8 + 9.6) and Fe (1260 + 159.2) in P. aurita, while T. fuscatus were, Cu (33.3 + 1.43), Zn (77.7 + 9.19) and Fe (1985 + 4.89). These values were higher than the guideline of WHO, and FEPA. The estimated daily intake of the metals in the periwinkles was all higher than their provisional tolerable daily and weekly intakes set by regulatory bodies. The non-carcinogenic risks (THQ and HI) of the individual and combined risk of the metals were within the limit of 1 set by USEPA, indicating no health risk at the moment. However, considering the bioaccumulative nature of heavy metals moderate intake of these periwinkles are recommended to avoid human health risk to consumers in future.Key words: Heavy metal, Pollution, Risk Assessment, Perewinkles

Toxicity comparison of water-accommodated fraction and chemically enhanced fraction of bonny light crude oil and dispersit SPC 1000 to mudskipper (Periophthalmus papilio) fish

This study assessed the physicochemical characteristics and toxicity of water-accommodated fraction (WAF) and chemically enhanced WAF (CEWAF) of Bonny Light Crude oil and Dispersit SPC 1000 (dispersant) to Mudskipper fish (Periophthalmus Papilio). There were variations in the levels of the physicochemical parameters. The coefficient of variation (CV) indicated that the temperature show the least variation of 2.24% and salinity the highest 98.12%.Hypothesis test for significant differences at p &lt; 0.05 significance level however, showed that there were no significant differences in the levels of the measured parameters over the 96 hours. All the mudskippers fish samples exposed to the water accumulated water fraction of 10% bonny oil survived beyond 96 hours. An increase in toxicity of the oil was observed after 72-96 hour exposures of the mudskipper to the oil and dispersant CEWAF. For dispersant concentrations of 540 ml/L and 630 ml/L the survival of mudskippers was 80%. These mortalities might be due to the toxic effect of the dispersant, Dispersit SPC 1000.The Total Petroleum Hydrocarbon (TPH) and the Polycyclic Aromatic Hydrocarbon (PAH) in the test media were respectively 7.66-63.18 ppm and 0.82-5.26 ppm.10% Bonny light crude oil WAF had no effects on mudskipper survival. Exposures to 540 ml/L and 630 ml/L Dispersit SPC 1000 dispersed oil WAF (CEWAF) resulted in 20 % mortality. The lethal dose concentration was 885.5 ml/L (88.55%). The lowest observed effect concentration (LOEC) was found to be 540 ml/L.Keywords: Water-accommodated fraction, chemically enhanced fraction, Dispersant, Mudskipper fis

Single and Joint Toxicological Effect of Dispersit SPC 1000 and Bonny Oil on Mudskipper Fish (Periophthalmus Papilio) from the Brackish Waters of Buguma, Rivers State, Nigeria

Marine oil spillage accidents greatly impact major risks to the environment in terms of the acute and chronic adverse effects not only to the offshore, but also the coastal ecosystem. This study assessed single and joint toxicological effect of Dispersit SPC 1000 and Bonny Oil on mudskipper fish (Periophthalmus papilio) from the brackish water research station of African Regional Aquaculture Centre, Buguma, Rivers State, Nigeria. The physicochemical parameters observed throughout the study were the pH, alkalinity and salinity were 6.83 ± 0.1, 40 mg/L± 0.2 and 17,655 mg/L respectively. The temperature and Dissolved oxygen (D.O.) and specific gravity averaged 26.7oC ± 0.1, 5.70 mg/L ± 0.02 and 1.008 ± 0.001, respectively. Dispersit SPC 1000 was found to be toxic to the mudskipper at various % (v/v) concentration, above 60 % (v/v) concentration no fish survived after one hour. The relation between the probit mortality and log concentration showed a strong positive correlation between the dispersant concentration and fish mortality within 3 hours, with r2 = 0.813 p = 0.05;The lethal dose Lc50 was 73.48%. Within 6 hours, the mortality increased as the dispersant exposure concentration was increased (r2 = 0.872, p =0.05). The results of exposure of the mudskippers to the water-oil-dispersant mix (CEWAF) showed lower mortalities. Mortality was observed after 72 hours for dispersant concentration above 54 %. 63% dispersant concentrations, 20% mortalities was observed between 72 and 96 hours. Dispersit SPC 1000 alone was highly toxic, and the toxicity of CEWAF was primarily caused by the presence of dispersant. There was no joint increase in toxicity between bonny oil and the chemical dispersant, as the mixing of the dispersant by the oil resulted in diminished toxicity of CEWAF and lower mortality.Keywords: Joint Toxicity, Dispersit SPC1000, Mudskipper Fis

Evaluation of Activated Carbon from Fluted Pumpkin Stem Waste for Phenol and Chlorophenol Adsorption in a Fixed \u2013Bed Micro-Column

Fluted pumpkin stem waste, which is both a waste and pollutant, was chemically modified with ortho-phosphoric acid and used to adsorb phenol and chlorophenol in fixed bed micro column It was found that the carbon bed sorption capacity for phenol and chlorophenol (77.20 and 80.0 mg/g) were higher than the equilibrium sorption studies. The critical bed depth increased with increasing phenol and chlorophenol concentrations. An increase in phenol and chlorophenol concentration from 100 to 200mg/l increased the rate constant, critical bed depth (Do) and bed sorption capacity, for phenol 77.20 to 160.00mg/g and chlorophenol 80.00 to 173.20mg/g. The breakthrough time, exhaustion time, uptake capacity decreased as the flow rate increased. Chlorophenol and phenol uptake capacity increased with increase in bed height. Experimental data for the change in concentration were correlated using the bed depth service time (BDST) model. In all parameters determined chlorophenol had better adsorption than phenol. Fluted pumpkin is the largest consumed vegetable in the West African sub region and therefore, creates one of the major agro waste problems in Nigeria. Preliminary investigations showed that several tons of these waste are produced daily in market places around the country but scarcely useful and therefore create environmental nuisance. The results obtained could be useful for the application of agricultural wastes for phenol and chlorophenol removal from industrial wastewate

KINETICS OF CHLOROPHENOL ADSORPTION ONTO COMMERCIAL AND FLUTED PUMPKIN ACTIVATED CARBON IN AQUEOUS SYSTEMS

ABSTRAC

Effect of 2-mercaptoethanoic acid treatment of fluted pumpkin waste (<i style="">Telfairia occidentalis </i>Hook. f.) on the sorption of Ni²⁺ ions from aqueous solution

613-620Differential sorption behaviour of pure and acid treated pumpkin waste biomass on the sorption of Ni2+ ion from aqueous solution was assessed by an ensemble of sorption techniques. Biomass was chemically treated by 0.50 N and 1.00 N 2-mercaptoethanoic acid solutions. Sorption capacity calculations from Langmuir isotherm model reveals the following amounts of Ni2+ ions bound per gram of biomass: pure, 12.69; 0.5 N acid treated, 40.0; and 1.0 N acid treated, 42.19 mg/g. The sorption probabilities for Ni2+ onto pure and differentially acid treated biomass were 0.19, 0.22 and 0.31 respectively. Acid treatment significantly enhanced the adsorption potential, adsorption density and sorption probability of biomass towards the metal ion. The negative values of Ea suggest that sorption process is exothermic. This study demonstrates that fluted pumpkin waste could be utilized as low cost, environment friendly biosorbent for the removal of Ni2+ and other trace metals from aqueous solution

Evaluation of Activated Carbon from Fluted Pumpkin Stem Waste for Phenol and Chlorophenol Adsorption in a Fixed –Bed Micro-Column

Fluted pumpkin stem waste, which is both a waste and pollutant, was chemically modified with ortho-phosphoric acid and used to adsorb phenol and chlorophenol in fixed bed micro column It was found that the carbon bed sorption capacity for phenol and chlorophenol (77.20 and 80.0 mg/g) were higher than the equilibrium sorption studies. The critical bed depth increased with increasing phenol and chlorophenol concentrations. An increase in phenol and chlorophenol concentration from 100 to 200mg/l increased the rate constant, critical bed depth (Do) and bed sorption capacity, for phenol 77.20 to 160.00mg/g and chlorophenol 80.00 to 173.20mg/g. The breakthrough time, exhaustion time, uptake capacity decreased as the flow rate increased. Chlorophenol and phenol uptake capacity increased with increase in bed height. Experimental data for the change in concentration were correlated using the bed depth service time (BDST) model. In all parameters determined chlorophenol had better adsorption than phenol. Fluted pumpkin is the largest consumed vegetable in the West African sub region and therefore, creates one of the major agro waste problems in Nigeria. Preliminary investigations showed that several tons of these waste are produced daily in market places around the country but scarcely useful and therefore create environmental nuisance. The results obtained could be useful for the application of agricultural wastes for phenol and chlorophenol removal from industrial wastewate