Estimated capital costs of fish exclusion technologies for hydropower facilities.

Hydropower is a reliable source of renewable energy, and its future expansion is likely to be in the form of either smaller new stream development (NSD) projects or powering existing non-powered dams. Thresholds for entrainment risk to fish and the requirements for fish exclusion at hydropower facilities often differ depending on the species involved, the characteristics of the facility, and the goals of stakeholders, but little quantitative information is present within the literature regarding the specific costs of fish exclusion measures. Cost data associated with protection, mitigation, and enhancement (PM&E) measures related to positive barrier screening were identified using keyword searches of an existing environmental mitigation cost data set and manual extraction from regulatory licensing documents available in the Federal Energy Regulatory Commission (FERC) eLibrary. This approach yielded a total of 50 p.m.&E mitigation measures with estimated capital construction costs pertaining to positive barrier screens and represented <10% of the 171 total FERC project dockets available in the data set. These data were highly skewed toward conventional relicensing projects, as <7% were associated with NSD projects. Results indicate highly variable costs are associated with fish screening, with flow-normalized costs one to two orders of magnitude higher for screening with the highest exclusion capability (≤0.09 in. spacing) compared with coarser screening (1-2 in.). These data provide an initial baseline for estimating exclusion costs for hydropower development and may help developers consider options for more fish-friendly generation technologies, though gaps remain relating to a lack of data, particularly for NSD projects.

Evaluating the incentive for soil organic carbon sequestration from carinata production in the Southeast United States.

Soil organic carbon (SOC) can be increased by cultivating bioenergy crops to produce low-carbon fuels, improving soil quality and agricultural productivity. This study evaluates the incentives for farmers to sequester SOC by adopting a bioenergy crop, carinata. Two agricultural management scenarios - business as usual (BaU) and a climate-smart (no-till) practice - were simulated using an agent-based modeling approach to account for farmers' carinata adoption rates within their context of traditional crop rotations, the associated profitability, influences of neighboring farmers, as well as their individual attitudes. Using the state of Georgia, US, as a case study, the results show that farmers allocated 1056 × 103 acres (23.8%; 2.47 acres is equivalent to 1 ha) of farmlands by 2050 at a contract price of $6.5 per bushel of carinata seeds and with an incentive of $50 Mg-1CO2e SOC sequestered under the BaU scenario. In contrast, at the same contract price and SOC incentive rate, farmers allocated 1152 × 103 acres (25.9%) of land under the no-till scenario, while the SOC sequestration was 483.83 × 103 Mg CO2e, which is nearly four times the amount under the BaU scenario. Thus, this study demonstrated combinations of seed prices and SOC incentives that encourage farmers to adopt carinata with climate-smart practices to attain higher SOC sequestration benefits.

Hydrogeochemical analysis and groundwater quality assessment of Ughelli South, Southern Nigeria.

This study investigated the groundwater quality in Ughelli South, Southern Nigeria, and the factors that are affecting it. Fifty groundwater samples were collected from various wells and tested for physical, chemical, and heavy metal contents. The data were analyzed using various techniques such as descriptive statistics, correlation analysis (CA), principal component analysis (PCA), and hydrochemical characterization. Findings revealed that the study area's groundwater was slightly acidic, with most variables falling within recommended limits except for lead, manganese, and copper, which were in the marginal category in 78%, 6%, and 2% of the samples, respectively. The CA and PCA identified lead as the most significant pollutant in the area. The hydrochemical characterization revealed that rock weathering was the primary process influencing the water chemistry and that the water is suitable for irrigation. The water quality index revealed that 72% of the samples were in the good to excellent water class, while the remaining 28% were in the poor to a very poor water class which may be due to lead pollution. The concerned authorities should take necessary precautions to prevent further deterioration.

Contribution of groundwater to dietary requirements of essential metals in Lagos and Ogun States, Nigeria.

Knowledge of dietary intakes of essential elements in groundwater is important for proper assessment of the actual contribution of drinking water to daily nutrient requirements. This study assessed the daily intake of nutritional elements in drinking groundwater of Lagos and Ogun States of Nigeria. One hundred and seventy (170) water samples were collected and analyzed for thirteen (13) nutritional elements (K, Mg, Ca, Co, Fe, Cu, Zn, Mo, Se, Na, Mn, Cr, and I) by Inductively Coupled Plasma-Mass Spectrometry (ICP/MS). Chronic daily intake CDI of the nutritional elements was higher for children and infants than adults in all cases. Percentages of tolerable daily intake reference value (TIRV) obtained for Lagos State groundwater were Mg 0.425%, Ca 0.309%, Fe 14.0%, Cu 1.84%, Zn 6.25%, Mo 0.057%, and Mn 1.08%; for Ogun State groundwater, % TIRV were Mg 1.99%, Ca 0.586%, Fe 81.1%, Cu 2.12%, Zn 9.21%, Mo 1.16%, and Mn 0.023%. The order of dermal absorption by an adult in Lagos when the water is used for bathing daily was Cr > Mn > Fe > Zn > Cu while the order in Ogun was Fe > Mn > Zn > Cu > Cr. The research concluded that groundwater alone cannot provide enough essential elements for human dietary needs in the study area.

Prevalence and Pattern of Alcoholic Beverage Consumption among Undergraduates in Remo, Ogun State, Southwest, Nigeria.

BACKGROUND: Alcoholic beverages come in various shades and flavours, often intensely advertised to the youthful population on various media channels within the state. Excessive intake is known to have deleterious effects on several dimensions of health. This study therefore assessed the prevalence and pattern of alcoholic beverage consumption among undergraduates in Remo division of Ogun State, Nigeria. METHODS: A cross-sectional study was carried out among 420 students attending three tertiary institutions in Remo area, Ogun State, selected via multi-stage sampling. Data were collected using a validated self-administered, semi-structured questionnaire and analyzed with SPSS 20.0. Relevant descriptive and inferential statistics were calculated (p<0.05). RESULTS: The mean age of respondents was 20.12±3.2 years, with 219 (54.3%) being female. Only 14 (3.5%) respondents believed alcoholic beverage consumption was good. One hundred and forty-two (35.2%) participants consumed alcoholic beverages. Of these, 58 (40.8%) engaged in binge drinking; 28 (19.7%) drank daily; 101 (70.9%) consumed wines and related drinks. One hundred and twenty (84.5%) of these respondents had difficulty controlling their intake; 25 (17.6%) got drunk; 16 (11.3%) got into fights; 35 (24.6%) skipped meals after drinking; 39 (27.5%) experienced some difficulty with memory; 52 (36.6%) had parents who consumed alcoholic beverages regularly. Alcohol consumption was significantly associated with: age; parents' occupation; living arrangement and religion. CONCLUSION: Alcoholic beverage consumption was slightly high, with majority of these respondents drinking at a moderate level. Targeted behaviour change communication and counseling services will be most beneficial to address this emerging public health concern.

CONTEXTE: Les boissons alcoolisées se présentent sous diverses formes et saveurs, et font souvent l'objet d'une publicité intense auprès des jeunes sur les jeunes sur divers médias de l'État. On sait qu'une consommation excessive a des effets délétères sur plusieurs dimensions de la santé. Cette étude a donc évalué la prévalence et les habitudes de consommation de boissons alcoolisées parmi les étudiants de premier cycle de la division Remo de l'État d'Ogun, Nigeria. MÉTHODES: Une étude transversale a été réalisée parmi 420 étudiants fréquentant trois institutions tertiaires dans la région de Remo, dans l'État d'Ogun, sélectionnés via un échantillonnage à plusieurs degrés. Les données ont été collectées à l'aide d'un questionnaire validé auto-administré, questionnaire semi-structuré validé et analysées avec SPSS 20.0. Les statistiques descriptives et inférentielles pertinentes ont été calculées (p<0,05). RÉSULTATS: L'âge moyen des répondants était de 20,12±3,2 ans, 219 (54,3 %) étaient des femmes. Seuls 14 répondants (3,5 %) pensaient que la consommation de boissons d'alcool était bonne. Cent quarantedeux (35,2 %) participants ont consommé des boissons alcoolisées. Parmi eux, 58 (40,8 %). s'adonnaient à la consommation excessive d'alcool ; 28 (19,7 %) buvaient quotidiennement ; 101 (70,9 %), ont consommé des vins et des boissons apparentées. Cent vingt (84,5 %) de ces répondants ont eu des difficultés à contrôler leur consommation ; 25 (17,6 %) se sont enivrés ; 16 (11,3 %) se sont bagarrés ; 35 (24,6 %) ont sauté des repas après avoir bu ; 39 (27,5 %) ont éprouvé des difficultés de mémoire ; 52 (36,6 %) avaient des parents qui consommaient régulièrement des boissons alcoolisées. La consommation d'alcool est significativement associée à l'âge, à la profession des parents, au mode de vie et à la religion. CONCLUSION: La consommation de boissons alcoolisées était légèrement élevée avec la majorité de ces répondants consommant à un niveau modéré. Des services de communication et de conseil ciblés sur les changements de comportement seront les plus bénéfiques pour répondre à ce nouveau problème de santé publique. MOTS CLÉS: Alcool, Prévalence, Étudiants de premier cycle, Boissons, Sud-ouest.

Multichannel fiber Bragg grating for temperature field monitoring.

We demonstrate a multichannel fiber Bragg grating (MC-FBG) based distributed temperature field sensor with millimeter-order spatial resolution. The MC-FBG was designed by using the layer peeling (LP) algorithm with a tailored group delay characteristic and fabricated using seamless UV-inscription. We have achieved a 21-channel MC-FBG with 0.2 nm bandwidth of each channel and 0.5 nm channel gap. The sensor was tested by using a temperature field distribution. Experimental results show that the sensor had a spatial resolution of 3 mm and could measure a maximum temperature gradient of 7.85 °C/mm.

Elemental enrichment of sediments in an unprotected shallow groundwater of Lagos and Ogun States, Nigeria.

Sediments quality is a good indicator of pollution in a water body where various elements were concentrated. Limited information is available on sediments from hand-dug wells. The present study evaluates sediment samples collected from groundwater of Lagos and Ogun States, Southwest Nigeria. Twenty sediment samples were collected from shallow groundwater, and ten rock samples were also collected from the vicinity of recently dug wells. Trace elements were determined in both the sediments and the rock samples using inductively coupled plasma-mass spectrometry. The enrichment factor was calculated for different elements using Fe, Ti, Mn and Cu as normalizing elements. The order of sediment contamination with each normalizing elements are Cu > Mn > Ti > Fe. The geo-accumulation (Igeo) indexes for Cr, Pb, Cu and Ni are 1.31, 1.05, 1.94 and 1.85, respectively. The Igeo for Lagos sediments is in the order Cr > Pb > Ni > Cu, while in Ogun sediments the order is Cu > Ni > Cr > Pb. The results were compared with Canadian Council of Ministers of Environment values of threshold effect level and probable effect level, which shows the sediments are not toxic. The pollution load index and ecological risk index values are 2.463 and 0.0014, respectively, which further indicates the sediments are not toxic in nature. The major source of most elements in sediments is the host rocks found in the vicinity of the groundwater while high level of some elements recorded in sediments are from the anthropogenic sources.

Evaluation of rare earth elements in groundwater of Lagos and Ogun States, Southwest Nigeria.

Rare earth elements in our environment are becoming important because of their utilization in permanent magnets, lamp phosphors, superconductors, rechargeable batteries, catalyst, ceramics and other applications. This study was conducted to evaluate the level of rare earth elements (REE) and the variability of their anomalous behavior in groundwater samples collected from Lagos and Ogun States, Southwest, Nigeria. REE concentrations were determined in 170 groundwater samples using inductively coupled plasma-mass spectrometry, while the physicochemical parameters were determined using standard methods. Lagos State groundwater is enriched with REE [sum REEs range (mean ± SD)]; [0.365-488 (69.5 ± 117)] µg L-1 than Ogun State groundwater [sum REEs range (mean ± SD)]; [1.14-232 (22.6 ± 41.1)] µg L-1. Boreholes are more enriched with REEs than wells. Significant (P < 0.05) positive correlation (R = Pearson) was recorded in Lagos State groundwater between sum REEs and Fe (R = 0.55). However, there were no significant correlations between sum REEs, pH (R = 0.073) and HCO32- (R = 0.157) in Ogun State groundwater. Chondrite-normalized plot shows that Lagos groundwater exhibits positive Ce anomaly, while Ogun State groundwater does not. The source of REE in Lagos State may be from the ocean and leaching from wastes dumpsites, while the source in Ogun State groundwater may be from the rocks.

Toxic elements in groundwater of Lagos and Ogun States, Southwest, Nigeria and their human health risk assessment.

A good quality drinking water is essential for human survival. However, a large percentage of the populations in most developing countries (Nigeria inclusive) do not have access to potable water. This study was therefore conducted to assess the extent of risk arising from consumption of toxic elements in groundwater samples collected from Lagos and Ogun States, Southwest, Nigeria. Twelve toxic elements concentrations (As, Mn, Cd, Cr, Pb, Ni, Al, Ti, V, Hg, Li, and Sn) were determined from 170 groundwater samples using inductively coupled plasma-mass spectrometry, and the physicochemical parameters were determined using standard methods. The pH results revealed that most of the water samples were slightly acidic. Of the twelve toxic elements, only Mn, Cd, Pb, Ni, and Al have concentrations higher than the WHO recommended limit in drinking water. The average dose of Mn and Al consumed daily from groundwater by an adult in Lagos state is 3.4 and 23.2 (µg/kg body weight), respectively. Similarly, an adult in Ogun State consumed an average daily dose of 6.09 and 25 (µg/kg body weight) Mn and Al, respectively. A greater threat was posed to children and infants. The order for risk of cancer in groundwater from Lagos State was Pb > Cr > As > Cd while the order in Ogun State groundwater was Cr > Cd > As > Pb. The relative high concentrations of Mn, Al, and Pb obtained in this study can be attributed to industrial and anthropogenic activities in the study area. Treatment of groundwater before consumption is recommended to avoid possible adverse cumulative effect. Improved waste disposal methods and regular monitoring of toxic elements in groundwater of the study area should be adopted to safeguard human health.

Heavy metal contamination in tailings and rocksamples from an abandoned goldminein Southwestern Nigeria.

Active and abandoned primary and secondary goldmines have been observed to be major sources of metals into the environment. This study assessed the level of metal concentrations in rock and tailing samples collected from the abandoned primary goldmine site at Iperindo. A total of five rock and ten tailing samples were collected for this study. The tailing samples were subjected to physicochemical analysis using standard methods. The samples were analyzed for metals using inductively coupled plasma/optical emission spectrometry technique. The results obtained indicated that tailings were acidic (pH 5.02), with electrical conductivity 133.4 µS/cm, cation exchange capacity 8.95 meq/100 g, available phosphorus was 4.74 mg/L, organic carbon 5.58 %, and organic matter 9.63 %. The trends for metal concentrations within the samples were in the order: Zn > Cu > Co > Pb > Cr > As > Cd for rock samples, Cu > Zn > Cr > Pb > As > Co > Cd in tailing samples. Cd, Pb, and Zn in the rock were above the Abundance of Elements in Average Crustal Rocks standards. Principal component analysis showed higher variations among samples in Iperindo. Cd, Pb, Cr, Co, Cu, As, and Zn were strongly loaded to principal component 1, with these metals significantly contributing to variations in 65.76 % of rock and 53.24 % of tailing. This study suggests that the metal concentration in tailings is a reflection of the metal composition of the rocks.

Groundwater fluoride and dental fluorosis in southwestern Nigeria.

This study was carried out to assess the fluoride levels of groundwater from open wells, consumed by the residents of three communities located in two distinct geological terrains of southwestern Nigeria. Fluoride concentration was determined using spectrophotometric technique, while analysis of other parameters like temperature, pH and total dissolve solids followed standard methods. Results of the analysis indicated that groundwater samples from Abeokuta Metropolis (i.e., basement complex terrain) had fluoride content in the range of 0.65 ± 0.21 and 1.20 ± 0.14. These values were found to be lower than the fluoride contents in the groundwater samples from Ewekoro peri-urban and Lagos metropolis where the values ranged between 1.10 ± 0.14-1.45 ± 0.07 and 0.15 ± 0.07-2.20 ± 1.41 mg/l, respectively. The fluoride contents in almost all locations were generally higher than the WHO recommended 0.6 mg/l. Analysis of Duncan multiple range test indicated that there is similarity in the level of significance of fluoride contents between different locations of same geological terrain at p ≤ 0.05. It was also observed that fluoride distribution of groundwater samples from the different geological terrain was more dependent on factors like pH and TDS than on temperature. The result of the analyzed social demographic characteristics of the residents indicated that the adults (between the age of 20 and >40 years) showed dental decay than the adolescent (<20 years). This signifies incidence of dental fluorosis by the high fluoride content in the drinking water of the populace. Further investigation on all sources of drinking water and other causes of tooth decay in the area is suggested.

Bioremediation of industrially contaminated soil using compost and plant technology.

Compost technology can be utilized for bioremediation of contaminated soil using the active microorganisms present in the matrix of contaminants. This study examined bioremediation of industrially polluted soil using the compost and plant technology. Soil samples were collected at the vicinity of three industrial locations in Ogun State and a goldmine site in Iperindo, Osun State in March, 2014. The compost used was made from cow dung, water hyacinth and sawdust for a period of twelve weeks. The matured compost was mixed with contaminated soil samples in a five-ratio pot experimental design. The compost and contaminated soil samples were analyzed using the standard procedures for pH, electrical conductivity (EC), organic carbon (OC), total nitrogen (TN), phosphorus, exchangeable cations (Na, K, Ca and Mg) and heavy metals (Fe, Mn, Cu, Zn and Cr). Kenaf (Hibiscus cannabinus) seeds were also planted for co-remediation of metals. The growth parameters of Kenaf plants were observed weekly for a period of one month. Results showed that during the one-month remediation experiment, treatments with 'compost-only' removed 49 ± 8% Mn, 32 ± 7% Fe, 29 ± 11% Zn, 27 ± 6% Cu and 11 ± 5% Cr from the contaminated soil. On the other hand, treatments with 'compost+plant' remediated 71 ± 8% Mn, 63 ± 3% Fe, 59 ± 11% Zn, 40 ± 6% Cu and 5 ± 4% Cr. Enrichment factor (EF) of metals in the compost was low while that of Cu (EF=7.3) and Zn (EF=8.6) were high in the contaminated soils. Bioaccumulation factor (BF) revealed low metal uptake by Kenaf plant. The growth parameters of Kenaf plant showed steady increments from week 1 to week 4 of planting.

Objective structured clinical examination vs traditional clinical examination: An evaluation of students' perception and preference in a Nigerian medical school.

BACKGROUND: Method of testing clinical competence of medical students in this setting has been controversial. This report evaluates the perceptions and preferences of 5(th) and 6(th) year medical students about traditional clinical examination (TCE) and objective structured clinical examination (OSCE). MATERIALS AND METHODS: A cross-sectional study using a structured questionnaire, administered to 156 students, who had been previously exposed to TCE and OSCE. RESULTS: There were 110 (70.5%) males and 46 (29.5%) females, with median age group of 26-30 years. One hundred and thirty-one respondents (84%) felt TCE is more difficult and 20 (12.8%) felt OSCE was more difficult. One hundred and forty-two (91%) felt OSCE was easier to pass, 8 (5.1%) felt TCE was easier to pass and 6 (3.8%) were undecided. Majority of the 5(th) and 6(th) year students (95.5% and 100%, respectively) preferred OSCE for assessment. In relation to validity and reliability of OSCE, 124 (79.5%) of all the students felt it provides a true measure of essential clinical skills, 130 (83.3%) felt its scores are standardised, 143 (91.7%) felt it is a practical and useful experience and 135 (86.5%) felt students' personality, ethnicity and gender will not affect OSCE scores. Overall, there were no significant differences in preference and perceptions between 5(th) and 6(th) year students and between males and females. CONCLUSION: Students preferred OSCE as method of assessing clinical competence and considered it a more valid and reliable method of examination.

Hexamethonium produces both twitch and tetanic depression without fade in common African toad (Bufo regularis).

The study was designed to investigate the nature of the cholinoceptors at the sciatic nerve-gastrocnemius muscle junction of the common African toad (Bufo regularis). Using myographic technique, the twitch properties of the sciatic-gastrocnemius muscle preparation of the common African toad was studied. Both the twitch height and peak tetanic height were measured as a percentage of control. Hexamethonium at a concentration of 0.1 mM significantly [P<0.05] reduced the mean twitch height from 2.62 cm to 1.0 cm and mean peak tetanic height from 5.38 cm to 4.32 cm. Hexamethonium, however does not produce tetanic fade at the same concentration. We hypothesized that the cholinoceptors of the neuromuscular junction of the common African toad (Bufo regularis) resemble the developing synapse of African clawed toad (Xenopus laevis) and may contain muscarinic M1 autoreceptors at the pre juntional membrane.

Assessment of groundwater quality in a typical rural settlement in southwest Nigeria.

In most rural settlements in Nigeria, access to clean and potable water is a great challenge, resulting in water borne diseases. The aim of this study was to assess the levels of some physical, chemical, biochemical and microbial water quality parameters in twelve hand - dug wells in a typical rural area (Igbora) of southwest region of the country. Seasonal variations and proximity to pollution sources (municipal waste dumps and defecation sites) were also examined. Parameters were determined using standard procedures. All parameters were detected up to 200 m from pollution source and most of them increased in concentration during the rainy season over the dry periods, pointing to infiltrations from storm water. Coliform population, Pb, NO3- and Cd in most cases, exceeded the World Health Organization recommended thresholds for potable water. Effect of distance from pollution sources was more pronounced on fecal and total coliform counts, which decreased with increasing distance from waste dumps. The qualities of the well water samples were therefore not suitable for human consumption without adequate treatment. Regular monitoring of groundwater quality, abolishment of unhealthy waste disposal practices and introduction of modern techniques are recommended.

Assessment of iodine deficiency and goitre incidence in parts of Yewa Area of Ogun State, Southwestern Nigeria.

This study was carried out to determine the occurrence, prevalence and contributing factors to the incidence of goitre in Yewa north local government area of Ogun state, southwestern Nigeria. To achieve these objectives, soil, water, and cassava tubers were collected from four villages -- Igbogila, Egua, Sawonjo and Imoto and from Lagos (about 250 m to the ocean) as a reference location, in order to determine their iodine concentrations. The results of the analyses indicated a soil mean iodine range of 2.1-5.8 microg g(-1); a cassava mean iodine value of 2.3-3.5 mug g(-1) and a drinking water mean iodine value of generally <1.0 microg L(-1) in all the four villages. These values of iodine in soil and water of the four villages are considered low when compared with the soil iodine value of 7.4 microg g(-1) and water iodine value of 6.1 microg L(-1) obtained from Lagos. The limestone unit of the study area remains an inhibiting factor in the bioavailability of the iodine because of its alkalinity. Statistical analysis has shown that there was significant difference between iodine concentration in the soils and the drinking water, and a correlation between the soil iodine and organic matter content at p < 0.05. The correlation between soil iodine and granulometric fractions occurred at p < 0.01. Potential goitrogens in the commonly consumed cassava products might also have contributed to the prevalence of goitre in the study area. Both the females and the adults (i.e., less mobile groups) were found to be vulnerable to goitre development in these villages.

Syndrome of inappropriate antidiuretic hormone (SIADH) in measles and malaria infections.

Sodium concentrations and osmolalities of simultaneously obtained venous blood and urine have been determined in a total of 61 children consisting of 18 children with malaria infection, 18 children with measles infection and 25 age- and sex-matched controls. The mean plasma osmolalities in the malaria and measles groups were significantly lower than in the control group (p less than 0.01). There was no difference between the measles and malaria groups either in their plasma osmolality (p greater than 0.20) or urine osmolality (p greater than 0.10). The u/p ratios for both osmolality and sodium concentrations where significantly higher for both the measles and malaria groups than for the matched controls. There was no difference in the u/p values between the malaria and measles groups (0.02 greater than p greater than 0.10). We conclude from these results that measles and malaria infected children demonstrate inappropriate secretion of ADH. Every child with these conditions should be carefully evaluated for the detection of evidence of SIADH. This is more important for children with measles who are frequently anorexic and may need intravenous infusion for maintenance of hydration.