Heavy metal, proximate and microbial profile of some selected commercial marine fish collected from two markets in south western Nigeria

The study on the elemental, proximate and microbial composition of fresh samples of Scomber scombrus, Gadus macrocephalus, Saclina pilchradus and Jack mackerel was determined to gain the knowledge of the risk and benefits associated with indiscriminate consumption of marine fishes. Wet digestion was done for the samples and was analyzed for minerals, heavy metals and microorganisms. The species examined contained appreciable concentrations of moisture, protein, lipids and ash content suggesting that the fish species could be used as a good source of minerals. Heavy metals analyzed were above tolerable limits; therefore, it can be suggested that taste, size, freshness and other related external appearances should not be the only factor to be considered in making choice for marketing and consumption of marine and freshwater fishes in Nigeria.Keywords: Scomber scombrus, Gadus macrocephalus, Saclina pilchradus, Jack mackerel, elemental, proximate, microbial, heavy metalsAfrican Journal of Biotechnology, Vol. 13(10), pp. 1147-1153, 5 March, 201

Between and Betwixt Soil Fertility Improvement and Disease Transmission: An Assessment of the Suitability of Anaerobic Digestion Effluent for Direct Application as Fertilizer

Although anaerobic digestate has been identified as a rich source of essential plant nutrients, its safety measured by the concentration of pathogen present is of great concern to end users. This research explored the efficiency of the mesophilic biodigestion process in the stabilization and sanitization of cow dung and chicken droppings. 6kg each of cow dung and chicken droppings were collected fresh and free from impurities, pre-fermented, mixed with water in the ratio 1:1 by volume to form slurry, fed into the respective reactors and digested for 30 days at an average daily ambient temperature of 37oC. The pH of the medium fluctuated between 6.5 and 8.0. The analysis of the feedstock and effluent of the digesters showed that a total solids reduction of 75.3% and 60.1% were recorded for cow dung and chicken droppings respectively while the reductions in total coliforms were 95% and 70% respectively. E.coli and Shigella spp., were removed while Salmonella spp. and Klebsiella spp. where still present in the digestate. Notwithstanding these results, the digestate still requires further treatment for it to be suitable for application on unrestricted crops either as fertilizer; otherwise a health problem would be created as attempt is made to improve soil fertility

Assessment of Chemical Inhibitor Addition to Improve the Gas Production from Biowaste

The coexistence of sulphate-reducing bacteria and methanogenic archaea in the reactors during the anaerobic digestion from sulphate-containing waste could favor the accumulation of sulfide on the biogas, and therefore reduce its quality. In this study, the effect of sulphate-reducing bacteria inhibitor (MoO−2 4 ) addition in a two phase system from sulphate-containing municipal solid waste to improve the quality of the biogas has been investigated. The results showed that although SRB and sulphide production decreased, the use of inhibitor was not effective to improve the anaerobic digestion in a two phase system from sulphate-containing waste, since a significant decrease on biogas and organic matter removal were observed. Before MoO−2 4 addition the average values of volatile solid were around 12 g/kg, after 5 days of inhibitor use, those values did exceed to 28 g/kg. Molybdate caused acidification in the reactor and it was according to decrease in the pH values. In relation to microbial consortia, the effect of inhibitor was a decrease in Bacteria (44%; 60% in sulphate-reducing bacteria) and Archaea (38%) population

Evaluation of Metal Pollution in Groundwater in the Industrialized Environs in and Around Dindigul, Tamilnadu, India

Synoptic hydrogeochemical assessments of physico-chemical and metal concentrations were analyzed to understand the driving forces behind heavy and trace metal pollution dynamics in groundwater systems of the heavily industrialized Dindigul district of Tamilnadu (India). Seasonality in solute dynamics is mainly due to regional differences in recharging capacity of groundwater systems and associated hydrogeochemical processes. Rapid changes in land use coupled with industrialization result in contamination of groundwater with heavy and trace metals like Be, Cr, Mn, Zn, Mo, Ni, Co, As, Cu, Cd, Pb, and Fe. The Pearson correlation and the Principal Component Analysis demonstrate that the complex suite of multidimensional metal pollution sources is influencing the groundwater quality in this region. In addition, pollution indices like heavy metal pollution index (HPI), heavy metal evaluation index (HEI), and contamination factor (Cd) were used to characterize the groundwater quality with reference to the water quality standards. All results demonstrate that the Dindigul groundwater quality is severely polluted by a large suite of metals like Be, Cr, Mn, Zn, Mo, Ni, Co, As, Cu, Cd, Pb, and Fe. Hence stringent management policies are highly required to control the industrial pollution and to improve the regional groundwater quality for sustainable development of the regional environment