Effects of Crude Oil on Biomass and Protein Production by Aquatic Yeasts

Toxic effects of Bonny light crude oil on the growth of three aquatic yeasts namely Yarrowia lipolytica, Candida tropicalis and Debryomyces hansenii were studied based on their biomass and protein production. The species showed different responses to the toxic influences of various crude oil concentrations. The growth response was measured spectrophotometrically using optical density (OD) at 600nm. Yarrowia lipolytica responded positively to different crude oil levels. A general assessment indicated that 2% (v/v) crude oil concentration stimulated maximum growth and protein production of this organism. Lower yields were observed at reduced crude oil levels. Growth decreased gradually among Candida tropicalis and Debryomyces hansenii cultures in comparison to the control. Biomass of Candida tropicalis increased from 0.1 (OD600nm) at 0 h to 0.49 after 20 h at 0.5% crude oil concentration. This level gradually declined to 0.04 after 20 h cultivation at 1.5 % crude oil concentration. Maximum decline in optical density of this organism was observed at crude oil concentration of 2.0%. Protein levels for Candida tropicalis decreased from 0.13 mg/mL after 20 h at crude oil concentration of 0.5% to 0.04 mg/mL after 20 h at maximum crude oil concentration of 2%. The biomass of Debryomyces hansenii increased slightly from 0.1(OD600nm) at 0 h to 0.44 after 20 h at 0.5% crude oil level. Further decreases in OD values of this organism occurred progressively as the crude oil concentration was increased. Lowest protein yield was observed at a crude oil concentration of 2% at which the least protein production of 0.05 mg/mL was produced after 20 h.Key words: Crude oil, yeasts; protein; biomass

Optimized Remote Network Using Specified Factors As Key Performance Indices

This paper discuss the implementation of an optimized remote network, using latency, bandwidth and packet drop rate as key performance indicator (KPI) to measure network performance and quality of service (QoS). We compared the network performance characteristics derived on the Wide Area Network (WAN) when using Fiber, VSAT and Point-to-Point VPN across the internet respectively as the network infrastructure. Network performance variables are measured across various links (VAST, Fiber and VPN across the internet) and the corresponding statistical data is analyzed and used as base-line for the optimization of a corporate network performance. The qualities of service offered on the network before and after optimization are analyzed and use to determine the level of improvement on the network performance achieved

Post-Impact Assessment of Oil Pollution on Some Soil Characteristics in Ikot Abasi, Niger Delta Region, Nigeria

Following a large-scale crude oil spillage in 2007, soil surveys were conducted in 2008 and in 2012 for post-impact assessment of the pollution on some soil characteristics in Ikot Abasi, Niger Delta Area, Nigeria. Soil characteristics examined include: pH, organic carbon (C), total nitrogen (N), available phosphorus (P), exchangeable cations (Ca, Mg, Na, K) exchangeable acidity (EA), effective cation exchange capacity (ECEC) base saturation (BS), total petroleum hydrocarbons (TPH), micronutrients (Fe, Mn, Zn, Cu) and heavy metals (Cadmium (Cd) and lead (Pb)). Soil analysis results in 2008 showed phenomenally greater values in some characteristics compared to 2012 results – five years after the pollution. In 2008, soil pH (6.8), organic (201.4 g/kg), N (5.65 g/kg), TPH, Pb, Fe, Mn, Zn, Cu, and Cd (3294.9, 2316.3, 23086.8, 189.4, 31.25, 29.1 and 4.22 mg/kg, respectively), were extremely (between 1.77 x 105 and 1.2 x 102 percent) higher than the respective values in 2012. On the other hand, available P(6.8 mg/kg), Ca, Mg, Na, K, EA, ECEC (2.2, 1.1., 0.04, 0.08, 1.6, 5.0 cmol/kg, respectively) and BS (68.5%) in 2008 were relatively higher in 2012, indicating a suppressive effect of oil pollution on these characteristics. The results showed that oil pollution is accompanied by major soil nutrient imbalances and phenomenal increases in soil TPH and some heavy metals. However, the impact of the pollution diminishes with time. This has serious implications on agricultural productivity of the land, ground water pollution and health of the people. Also, remediation approach to adopt and payment of compensation should be based on the magnitude of the pollution and persistence of the impact of the pollution. Keywords: Impact assessment, oil pollution, soil characteristics, Niger Delta, Nigeria

Managing and Improving Upon Bandwidth Challenges in Computer Network

Managing the bandwidth of a computer network is always faced with great challenges. This research was necessitated by the urgent need to manage the University network currently experiencing congestion in both the local LA� and on the internet backhaul with a view to improving network performance and reduce the huge recurrent on the WA� link. However, there exists various ways that have been deployed towards solving these problems. In this paper we examined existing bandwidth management, effect of limited bandwidth on the network performance and profound solutions of techniques that enhanced or improved the bandwidth efficiency. Also, included in this research work are the studies of the effect of limited bandwidth on work load, type of protocol used and the effect of network congestion on the quality of service of a Wide Area �etwork (WA�). By comparison, from the modeling of the effect of work load and limited bandwidth on the throughput of a wide area network based on experimental simulation and real time simulation scenarios, some observations were made and recommendation of solutions were given from the analyzed results

Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate on the Prevalence of Microorganisms and Removal of Aluminum in Soil by Bitter Leaf Plant (Vernonia amygdalina Delile)

This research was carried out to investigate effect of ethylenediaminetetraacetic acid and ammonium oxalate on the prevalence of microorganisms and removal of aluminum in soil by bitter leaf plant (Vernonia amygdalina). The test plant was sown in aluminium-polluted soil (conc. = 150mg Al kg-1 soil). One gram of each chelating agent was dissolved in 1.5 litres of water and applied at different time intervals; application on a day prior to sowing of test plant in metal-polluted soil, application on the day of planting, application at one week after planting; at one month after planting. For the control soils, chelating agent were not added, although aluminium-contaminated. In the control, aluminium concentrations in leaf tissues were 16.20mg/kg compared to a staggering 9.20mg/kg in EW1 and 5.24mg/kg in OD1. However, heavy metal concentration of the leaves of Vernonia amygdalina in the control, EW1, EM1, OD-1 and OW1 were significantly similar (P>0.05). Concentration of aluminium in the stem tissues were also similar in ED1, EM1, OD-1, OD1 and OW1 (P>0.05) were concentration ranged from 5.42mg/kg to 7.98mg/kg. Compared to the control, aluminium concentration in stem tissues was 4.95mg/kg comparable with 3.42mg/kg in OM1. In the plant root, OD1 had the highest accumulation of aluminium in the root (16.92mg/kg); however concentrations of aluminium in the roots were also statically similar in OW1 (15.08mg/kg), OM1 (13.84mg/kg), OD-1 (14.72mg/kg), EM1 (15.12mg/kg) and in the control (13.52mg/kg). Results of the following also showed concentrations of residual aluminium in the soil ranging from 68.25mg/kg in the control to 109.85mg/kg in ED1 soil. After three months of planting, results show that the total bacteria count for ED1 (5.3 × 104 cfu/g) had the highest while OM1 (3.9 × 103 cfu/g) had the lowest. For fungi isolates, the highest was control (8.2 × 103 cfu/g) whereas the lowest were OD–1 (6.8 × 102 cfu/g). The most prevalent microorganisms in the spiked soil with heavy metal are Bacillus subtilis represented in all the samples for bacteria while Aspergillus niger representing fungi. The perseverance of the test plant in the aluminium spiked soil is an indication of adaptation to the stress imposed by the concentration of aluminium in soil. In spite of the metal composition within the soil, it was observed that a number of microorganisms existed. This may therefore suggest a favourable environment for the microorganisms within the soil rhizospheric region of Vernonia amygdalina.Keywords: EDTA, oxalate, aluminium, pollution, remediation, Vernonia amygdalin

The Community Scientist Program: Utilizing a multi-site rapid feedback approach to facilitate community engagement in research

https://openworks.mdanderson.org/sumexp22/1147/thumbnail.jp

Evaluation of risk caused by intake of trace metal through consumption of Pleurotus tuber-regium collected around automobile village in Abia State

ABSTRACT. The bioaccumulation of trace metals in mushrooms poses a health risk to consumers. Despite the fact that mushroom eating has been linked to numerous health advantages, little attention has been paid to the relative health risks associated with trace metal build-up in this nutritional source in Nigeria. Pb, Cd, Fe, Hg and As in Pleurotus tuber-regium collected from mechanic workshops in Umuahia were analysed and the associated health risks for the consumers were evaluated. The trace metal contents in the mushroom and its substrates showed a descending order of Fe > Pb > Cd > As > Hg. The heavy metals concentration ranges in fruity body of the Pleurotus tuber-regium were Fe (62.16-98.17 mg kg-1), Pb (0.18-1.21 mg kg-1), Cd (0.05-0.34 mg kg-1), As (0.25-0.51 mg kg-1) and Hg (0.009-0.021 mg kg-1). The estimation of weekly intake values was lower than PTWIs of mushroom species except for Fe. According to the THQ and the HI calculations for trace metal contents in the mushrooms, mercury did not pose any risk on human health; whereas the other determined trace metals gave THQ values of 1 < THQ < 10 and showed the possibility of long-term risk.                     KEY WORDS: Trace metals. Mushroom, Estimated weekly intake, Target hazard quotient, Bioaccumulation   Bull. Chem. Soc. Ethiop. 2021, 35(2), 229-241. DOI: https://dx.doi.org/10.4314/bcse.v35i2.

Combined effects of municipal and industrial wastes on the quality of the new northern Calabar River, Nigeria

This study was conducted to investigate the combined effects of municipal and industrial waste discharges on the quality of the new northern Calabar River in the Niger Delta province (5.317°N, 6.467°E) of Nigeria. Water samples were collected in June 2015 from five regions along the stretch of the river. The five regions comprised three observed pollution sources (abattoir, open market, and noodle factory) and two non-pollution sources at the downstream and upstream sections of the river. Using standard analytical protocols, results showed that the current pollution loads of the river varied significantly (p < 0.05) across the three pollution sources. Over 33% of studied quality indicators of the river including total hardness (1526.19±154 mg/l), biochemical oxygen demand (10.14±4 mg/l), and chemical oxygen demand (57.62±13 mg/l) over time increased beyond their permissible limits due to the disposal of municipal and industrial wastes into the river. The present quality of the river was only fair with a Water Quality Index of 64.71. This result suggests that the water quality is usually protected but occasionally impaired by the wastes discharged into the river, leading to conditions that often depart from permissible levels

Seasonal Variation and Pollution Assessment of Some Physicochemical Parameters of the Surface Water of Mahin Lagoon and Its Adjoining creeks, South-Western Nigeria

Indiscriminate discharge of untreated wastes from into the aquatic ecosystem may result in deterioration of water quality, as well as poses a great threat to the balance of aquatic ecosystems and human health. This study investigated the seasonal variation in physicochemical characteristics and assessed the pollution status of Mahin Lagoon and its adjoining creeks using standard method. Results of physico-chemical parameters varied significantly (p<0.05) across seasons and stations, with the following mean values: Temperature (27.79±0.96oC), salinity (7.65±0.99‰), conductivity (15.23±17.63µS/cm), pH (7.74±6.57), DO (7.65±0.99 mg/L), BOD (7.74±6.57mg/L), nitrate (8.00±3.67mg/L), sulphate (8.60±5.01mg/L), phosphate (3.88±1.55mg/L). Heavy metals were with the following mean values: Zn (7.15±6.31mg/L), Pb (0.04±0.21mg/L), Fe (10.63±6.02mg/L), Cu (1.16±1.72mg/L), Cr (0.02±0.00mg/L), Cd (0.01±0.08mg/L), Ni (0.28±0.45mg/L) and Co (0.26±0.44mg/L). The physic-chemical parameters were within the permissible limits recommended by International Organizations for lotic ecosystem. However, the single-factor pollution index (PI) classified pH, DO, BOD, Cu and Zn within the ‘medium pollution’ category while nitrate and phosphate indicated heavy pollution status. The PI also revealed that Cu, Fe and Ni were at serious pollution level while Co and Cr were at non-pollution level. The comprehensive pollution index revealed that the water was severely polluted (CPI < 2). The Hazard Quotients of heavy metals in the surface water were less than 1 (HQ < 1) indicating there was no risk to human health through ingestion or dermal contact. Therefore, the water from the Mahin lagoon and its adjoining creeks may still be suitable for domestic use and conducive for survival of aquatic life