Bioremediation of cutting fluids contaminated soil by Pleurotus tuber-regium Singer

This study investigated the effect of inoculation of Pleurotus tuber-regium, a Nigerian white rot fungus, period of incubation, different levels of contamination on cutting fluids degradation in contaminated soil over 30, 60, and 90 days. Control for different levels of cutting fluids was also used to compare rates of bioremediation of the contaminant in the soil. At the end of each incubation period, the mycelia-ramified substrate was separated from the soil layer and dried. The soil samples were analyzed for physico-chemical parameters; total petroleum hydrocarbon, lignin content by determining the acid detergent fraction (ADF), heavy metals content of the soil using flame atomic absorption spectrophotometer, and changes in the polyphenol oxidase and peroxidase activities were also determined after 1, 2, and 3 months. P. tuber-regium improved the nutrient status of the soil and increased enzyme activity was recorded. A reduction in the pH and heavy metal contents of the soil at all levels of cutting fluids concentrations was detected. The lignin in the rice straw decreased from 34.50% in the control to 8.06% at 30% cutting fluids concentration after 3 months of incubation. The highest TPH loss of 30.84% was recorded at 20% cutting fluids contamination after 3 months compared to 13.75% at the onset of the experiment. The improvement of the nutrient contents of the soil, bioaccumulation of heavy metals, degradation of TPH, lignin, and increased activity of polyphenol oxidase and peroxidase was due to biodegradation of the cutting fluids.     

Sustainable rural development in Sokoto State, Nigeria

In Nigeria, as in most countries, institutional barriers to successful rural development exist and need to be addressed. In Sokoto State, a variable and unpredictable Sahelian climate in combination with conditions of high population growth, low levels of income, and environmental degradation, create and intensify institutional challenges. This study examines the sustainability of government initiatives regarding the provision of agricultural inputs, assistance and extension services to farmers, and the extent to which agency efforts are coordinated and integrated, particularly regarding water management. In some cases, rural development agencies demonstrated the capability to meet the needs of the people. Some farmers were satisfied with government assistance and in some areas the tube well programme was quite successful. Yet in Sokoto State many institutional barriers to sustainable rural development exist and need to be addressed. In general, implementation strategies and management procedures appeared narrowly focused and placed little emphasis on coordination and integration among rural development agencies. The result was often inappropriate overlap or oversights in activities .     

Chemical composition of rivers and streams in the forest and savanna zones of Nigeria

The aim of this study is to investigate the differences in the chemical conditions of lotic waterbodies in the two major ecosystems in Nigeria, the forest and savanna zones. The forest waters were slightly acidic (mean±SD pH = 6.72±0.58) while the savanna waters were slightly alkaline (pH = 7.11±0.33). The cationic order of dominance in the forest waters was Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ in contrast to Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ in savanna waters. The forest waters were chlorided (typical of coastal and/or marine waters) whereas the savanna waters were carbonated in nature, typical of the worldwide freshwater. Organic carbon was significantly higher in forest waters than in the savanna waters (p < 0.05) while nutrient compounds were significantly higher in savanna waters than in forest waters. The seasonal variation of the chemical parameters was generally more evident in savanna than in forest waters. The differences in water quality between the two major vegetation zones reflect the differences in the biogeochemical processes and nutrient cycling that characterise forest and savanna ecosystems.     

Total petroleum hydrocarbons and trace heavy metals in roadside soils along the Lagos–Badagry expressway, Nigeria

This study reports the level of total petroleum hydrocarbons (TPH) and trace heavy metals (lead, copper, and cadmium) in soil samples collected randomly from Iyana–Iba garage, Lagos State University bus stop, Adeniran Ogunsanya College of Education bus stop, and a control site off Lusada–Atan road, near Crawford University, Igbesa, Ogun state. TPH was estimated gravimetrically after Soxhlet extraction and column clean up, while soil metals were determined by atomic absorption spectrometry using mineral acid digestion. For TPH, the sites have mean values of 19.43 ± 1.27, 16.11 ± 1.85, and 11.43 ± 4.33 mg/g with a control mean value of 0.33 ± 0.16 mg/g. For trace heavy metals, cadmium was not detected. However, the mean levels of lead are 4.24 ± 3.10, 3.72 ± 0.60, and 3.70 ± 1.32 μg/g, respectively, whereas mean copper concentrations are 20.63 ± 9.02, 19.35 ± 3.61, and 16.76 ± 3.02 μg/g in all sites, respectively, compared to the control mean of 0.25 ± 0.13 and 5.99 ± 1.23 μg/g for lead and copper, respectively. Sites studied have higher levels of TPH and metals compared to the control soil samples. This is indicated by a statistically significant difference found between the concentration of analyzed elements in soils collected along Lagos–Badagry expressway and the control site.     

Effect of electronic waste on E. coli genomic integrity: a possible role for metal induced carcinogenesis

Electronic waste (e-waste) poses a major public health threat for developing countries’ populations. The hazards of e-waste are exacerbated by crude recycling methods. In this study, the presence of metals in e-waste samples obtained from Lagos, Nigeria, was assessed using atomic absorption spectrometry. The effect of e-waste on Escherichia coli (E. coli) PQ-37 genomic integrity was evaluated using the SOS chromotest. The means of metal concentrations in the evaluated samples were 16 (cadmium), 7.3 (nickel), 11 (chromium), 20 (lead), 3100 (iron), 90 (zinc), and 2000 (copper) μg_L^?1. Damage to E. coli deoxyribonucleic acid (DNA) increased proportionally to the metal concentrations. Significant amounts of DNA damaging agents from inadequately processed e-waste are present in the studied environment, which will have implications for adverse effects on public and ecological health. Existing policies against dumping of toxic materials in susceptible communities should be enforced.     

High level leaching of heavy metals from colorful ceramic foodwares: a potential risk to human

Environmental Science and Pollution Research - Ceramic foodwares are among the products used by people on daily basis without being cautious of exposures to heavy metals through possible leaching...     

Ecotoxicology of glyphosate and recent advances in its mitigation by adsorption

Environmental Science and Pollution Research - Glyphosate (N-[phosphonomethyl]glycine) is one of the most popular herbicides now used in agricultural practice. The aim of this paper was to discuss...     

Efficient suspension freeze desalination of mine wastewaters to separate clean water and salts

Suspension freeze desalination is a promising technique for producing clean water from mine wastewaters. The principle is that growing ice crystals reject impurities during freezing. As a result, pure water is separated from mine wastewaters as clean ice. Actually, there is a need for improved techniques to increase water yield and purity. Here we tested ice formation in complex synthetic solutions during cooling and addition of seed. Solutions included: pure distilled water, 50, 33 g/L NaCl and 17, 50 g/L Na₂SO₄, 50 g/L NaCl and 50 g/L Na₂SO₄. Results show that heat of crystallization was the highest with pure distilled water at 8859 J, whereas the lowest heat of crystallization, of 4608 J, was for the solution of 50 g/L NaCl and 50 g/L Na₂SO₄, indicating that the presence of the salt enhances ice formation. As an application, we designed a new flow diagram, which, in addition to heat exchanger and ice filter, now includes a fluidized bed reactor for salt crystallization and recovery, and a separate heat exchanger for ice crystallization.