REWARD DOUGLAS - Academia.edu (original) (raw)

Papers by REWARD DOUGLAS

Bioremediation journal, Mar 4, 2024

Global Journal of Earth and Environmental Science, Feb 28, 2022

Heavy Metals - Recent Advances [Working Title]

Potentially toxic elements (PTEs) contamination in soils threats human wellbeing and ecological h... more Potentially toxic elements (PTEs) contamination in soils threats human wellbeing and ecological health because of their toxicity and bioaccumulation. This research presents a portable Olympus Delta Premium 6000 Series XRF Analyser (Olympus, USA) as a rapid measurement tool (RMT) for PTEs: Cr, Cu, Fe, Pb, Mn, and Zn in contaminated soils in the Niger Delta, Nigeria. A total of 45 crude oil-contaminated soils were collected from three genuinely oil spill sites. The range of measured PTEs concentrations (mg/kg) in the study sites are as follows: Site 1: chromium (Cr) 54–75, copper (Cu) 5.4–16.6, iron (Fe) 14,841–23,404, lead (Pb) 13.5–21.4, manganese (Mn) 158–555, and zinc (Zn) 32.6–47.2; Site 2: (35–66), (5–16.1), (10166–20,967), (12–17.8), (209–440), (17.6–33.6); and Site 3: (32–115), (6.5–20.8), (7538–22,800), (12–135), (98–338), (19.9–177). The trend of PTEs across the three sites follows the same order: Fe > Mn > Cr > Zn > Pb > Cu. The average concentration values o...

Applied Spectroscopy Reviews, 2019

Potentially toxic elements (PTEs) in soils pose severe threats to the environment and human healt... more Potentially toxic elements (PTEs) in soils pose severe threats to the environment and human health. It is therefore imperative to have access to simple, rapid, portable and accurate methods for their detection in soils. In this regards, the review introduces recent progresses made in the development and applications of spectroscopic methods for in-situ semi-quantitative and quantitative detection of PTEs in soil and critically compares them to standard analytical methods. The advantages and limitations of these methods are discussed together with recent advances in chemometrics and data mining techniques allowing to extract useful information based on spectral data. Furthermore, the factors influencing soil spectra and data analysis are discussed and recommendations on how to reduce or eliminate their influences are provided. Future research and development needs for spectroscopy techniques are emphasized, and an analytical framework based on technology integration and data fusion is proposed to improve the measurement accuracy of PTEs in soil.

Talanta, 2016

This manuscript reports on the performance of a hand-held diffuse reflectance (mid)-infrared Four... more This manuscript reports on the performance of a hand-held diffuse reflectance (mid)-infrared Fourier transform (DRIFT) spectrometer for the prediction of total petroleum hydrocarbons (TPH) in three different diesel-contaminated soils. These soils include: a carbonate dominated clay, a kaolinite dominated clay and a loam from Padova Italy, north Western Australia and southern Nigeria, respectively. Soils were analysed for TPH concentration using a standard laboratory methods and scanned in DRIFT mode with the hand-held spectrometer to determine TPH calibration models. Successful partial least square regression (PLSR) predictions, with coefficient of determination (R 2) $ 0.99 and root mean square error (RMSE) o200 mg/kg, were obtained for the low range TPH concentrations of 0 to $ 3,000 mg/kg. These predictions were carried out using a set of independent samples for each soil type. Prediction models were also tested for the full concentration range (0-60,000 mg/kg) for each soil type model with R 2 and RMSE values of $ 0.99 and o1,255 mg/kg, respectively. Furthermore, a number of intermediate concentration range models were also generated for each soil type with similar R 2 values of $ 0.99 and RMSE values o800 mg/kg. This study shows the capability of using a portable mid-infrared (MIR) DRIFT spectrometer for predicting TPH in a variety of soil types and the potential for being a rapid in-field screening method for TPH concentration levels at common regulatory thresholds. A novel hand-held mid-infrared instrument can accurately detect TPH across different soil types and concentrations, which paves the way for a variety of applications in the field.

14th International Conference of Sustainable Use and Management of Soil, Sediment and Water Resources (AquaConSoil 2017), Abstracts, 2017

Science of The Total Environment, 2018

This study investigated the sensitivity of visible near-infrared spectroscopy (vis-NIR) to discri... more This study investigated the sensitivity of visible near-infrared spectroscopy (vis-NIR) to discriminate between fresh and weathered oil contaminated soils. The performance of random forest (RF) and partial least squares regression (PLSR) for the estimation of total petroleum hydrocarbon (TPH) throughout the time was also explored. Soil samples (n=13) with 5 different textures of sandy loam, sandy clay loam, clay loam, sandy clay and clay were collected from 10 different locations across the Cranfield University's Research Farm (UK). A series of soil mesocosms was then set up where each soil sample was spiked with 10 ml of Alaskan crude oil (equivalent to 8450 mg/kg), allowed to equilibrate for 48 h (T2d) and further kept at room temperature (21 o C). Soils scanning was carried out before spiking (control TC) and then after 2 days (T2d) and months 4 (T4m), 8 (T8m), 12 (T12m), 16 (T16m), 20 (T20m), 24 (T24m), whereas gas chromatography mass spectroscopy (GC-MS) analysis was performed on T2d, T4m, T12m, T16m, T20m, and T24m. Soil scanning was done simultaneously using an AgroSpec spectrometer (305 to 2200 nm) (tec5 Technology for Spectroscopy, Germany) and Analytical Spectral Device (ASD) spectrometer (350 to 2500 nm) (ASDI, USA) to assess and compare their sensitivity and response against GC-MS data. Principle component analysis (PCA) showed that ASD performed better than tec5 for discriminating weathered versus fresh oil contaminated soil samples. The prediction results proved that RF models outperformed PLSR and resulted in coefficient of determination (R 2) of 0.92, ratio of prediction deviation (RPD) of 3.79, and root mean square error of prediction (RMSEP) of 108.56 mg/kg. Overall, the results demonstrate that vis-NIR is a promising tool for rapid site investigation of weathered oil contamination in soils

<i>Vis-NIR data spectra analysis and chemometric modelling</i>

For containment and water exclusion purposes, cement-bentonite (CB) barrier walls are usually bui... more For containment and water exclusion purposes, cement-bentonite (CB) barrier walls are usually built, with certain design criteria specified for the wall to fulfil intended purposes. While permeability is believed to be the most important criterion, it can be impacted by the stress-strain properties of the wall, which define the strength and stiffness. This study investigates the influence of curing time, confinement, rate of axial deformation, and quantity of cement (mix of Portland cement (PC) and ground granulated blast furnace slag (GGBS)) on the stress-strain properties of CB slurry walls. An unconfined compressive test supported by (i.e. UCT) undrained triaxial (UUT) tests were carried out on specimens prepared from two mix-designs (differentiated by the proportion of GGBS in the cement component) and cured 7, 14, 28, 60 and 90 days. Two rates of deformation (1.0mm/min and 1.2mm/min) were examined, using a range of confining pressure (i.e., 50 200 kPa) in the UUT. The results r...

International Journal of Research, 2020

This study was conducted to evaluate the phytoremediation capacity of Vetiveria Zizanioides in cr... more This study was conducted to evaluate the phytoremediation capacity of Vetiveria Zizanioides in crude oil-contaminated soils in Imiringi, Bayelsa State. 2000g sample of soil was collected, homogenised and divided into six equal parts A, B, C, D, E, and F, respectively. Sample B, D and F were artificially contaminated with 200 cm 3 of crude oil each and homogenised again. Samples A, C, and E served as control over B, D and F, respectively. This was followed by series of tests. First, Agaricus bisporus was added to Sample C to make it a Myco-rich environment. A. bisporus was also added to sample D. A. bisporus thrived on C for 4 days while it was observed to almost immediately decompose in D. Furthermore, grown Pistia stratiotes (Linn.) was transplanted on both Samples C and D at the same time. P. stratiotes (Linn.) on Sample C blossoms while within very few minutes of transplanting, P. stratiotes (Linn.) in Sample D lost its colouration and died within two (2) hours. Moreso, both the ...

Geosciences, 2015

An aspect of geophysical study using the Vertical Electrical Sounding (VES) technique was applied... more An aspect of geophysical study using the Vertical Electrical Sounding (VES) technique was applied in Ishiayi community in Ahoada west Local Government Area of Rivers State to delineate geo-electric stratigraphy and to access hydro-geological conditions. Six (6) VES points with an electrode spacing's of AB/2 147M and AB 294M were occupied along the traverses. Surface data were acquired with an ABEM SAS 1000 terrameter set. The data were interpreted using IP2 win computer software's. The results of the interpreted VES data and the drilled borehole logs confirms the following stratigraphy top moist soil (86-319Ωm), lateritic sand (44-631Ωm), silty clay layer (44-335Ωm), and saturated brownish sand (999-1056Ωm) as aquifer. Geophysical VES reports and borehole logs confirms that the area is a homogeneous formation consisting of consistent lithology of sand with intercalation of silty clay layer. Borehole logs further envisaged that the groundwater distribution network is uniform. Geo-electric sections further reveal that depth to groundwater is relatively shallow reflecting less than 5m virtually in all the locations. Water level generally reflects consistency within the surveyed area. Furthermore, the results of the interpretation of the VES data indicate that the thickness values of the aquifer vary from 8.16m to 30.91m. VES 1 and 2 reflect little thickness of aquifer within a depth ranges of 50-65ft and 30-35ft. However, VES 3, 4, 5 and 6 showed relatively thick column of the aquifers. Although, all the mapped aquifers in the investigated area are prolific but the thickness of the aquifer is a reflection of the hydraulic properties, such as water retention capacity and transmissivity. Hence, VES 3, 4, 5 and 6 show better hydraulic properties as a result, water abstractions wells were sited within depth range of (115.5-132ft). Thus, four (4) boreholes were drilled in aforementioned locations confirming the water to be good and free of iron concentration.