Investigation of lead (Pb), cadmium (Cd), zinc (Zn) and chromium (Cr) in soils and vegetables; and the consequent health risks connected with ingestion of the vegetables was conducted at Agbabu farm (F) settlement close to bitumen mining area of Ondo State, Nigeria. Soil and eleven vegetables were sampled from ten farms (Fs) and analyzed for Pb, Cd, Zn and Cr concentrations. Health risk parameters such as daily intake of metal (DIM), health risk index (HRI), target health quotient (THQ), and total diet target health quotient (TTHQ) were evaluated. Except Cd, other metals in soils were below their respective maximum allowable concentrations (MACs) set for agro soils. Only Cd and Pb were higher in vegetables than their respective MACs. Bioconcentration factors (BCFs) of the metals were higher in Talinum triangulare but lower for Cd, Zn, Cr and Pb in Solanum macrocarpon, Vernonia amygdalina , Ocimum gratissimum , and Taraxacum officinale respectively. DIMs of Cd, Zn and Pb for adults and children were higher than 0.0035, 0.001 and 0.300 mg/kg/day respective values of oral reference doses (RfD). The DIMs of Cr ingestion by children were above the RfD of Cr for all vegetables, while DIMs of ingesting Cr by adults were above Cr RfD for some vegetables. The (HRI >1) for Pb, Cd and Zn; (THQ >1) for Pb, Cd; and (TTHQ >1) indicated health risks in connection with the ingestion of these vegetables. These health risks were higher for children.

Graphyne and its family members (GFMs) are allotropes of carbon (a class of 2D materials) having unique properties in form of structures, pores and atom hybridizations. Owing to their unique properties, GFMs have been widely utilized in various practical and theoretical applications. In the past decade, GFMs have received considerable attention in the area of water purification and desalination, especially in theoretical and computational aspects. More recently, GFMs have shown greater prospects in achieving optimal separation performance than the experimentally derived commercial polyamide membranes. In this review, recent theoretical and computational advances made in the GFMs research as it relates to water purification and desalination are summarized. Brief details on the properties of GFMs and the commonly used computational methods were described. More specifically, we systematically reviewed the various computational approaches employed with emphasis on the predicted permeability and selectivity of the GFM membranes. Finally, the current challenges limiting their large-scale practical applications coupled with the possible research directions for overcoming the challenges are proposed.

Soil contamination resulting from petroleum hydrocarbon contaminants poses a fairly substantial hazard to human health and the environment. Phytoremediation, land farming, and chemico–biological stabilization were used to treat total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) at a crude oil polluted soil site in Nigeria. A field pilot study was conducted by preparing nine cells with subcells attached to each serving as a control with an overall area of 1.53 m2. A complete block design method was used for the study. The prepared soil sample cells were divided into three groups with each group having approximately 300 kg of soil and delineated as low, medium, and high test plots. The low samples were spiked with 6.1 kg of crude oil, the medium samples were spiked with 12.2 kg of crudeoil, and the high samples were spiked with 18.3 kg of crude oil. Each row containing three cells with low, medium, and high concentrations were treated separately using the three treatment methods. The ratio of the soil sample to the organic amendment for the treatments was 2:1. The results showed over 90% degradation in the initial concentration of TPH and PAHs across different contaminant levels except in the control subcells where only 30% of degradation was recorded. Multivariate analysis of variance was employed to assess the significant difference in each treatment group while inferential statistics using a mean performance plot was used to ascertain the optimum treatment method. Land farming, chemico–biological stabilization, and phytoremediation ranked 1, 2, and 3, respectively. In conclusion, the three treatment methods employed all degraded the contaminants (TPH and PAHs) with land farming emerging as the best method.

This paper examined the effects of brewery wastewater on the quality of water in Ikpoba River which has experienced significant pollution over the years, with the intention of determining the main pollutant in the river water. Samples were recovered from eight (8) different locations covering a total distance of 750 m: one sample from upstream at 150 m from the effluent discharge location, two samples from effluents discharge point and five samples from downstream location at 150 m interval. Samples were taken twice monthly in March, May and July, 2014 during period of intense activity of production. The physcio-chemical analyses of the twenty-five (25) selected parameters were calculated and values obtained were used to calculate the water Quality index of the river. The results indicated that Ikpoba River is severely polluted (WQI = -5429792.89, in SN1, March, 2014) as a result of untreated brewery effluent hence Principal Component Analysis (PCA) was applied to determine the parameter that contributes mainly to the pollution and those that contributed minimally. Evaluation of the PCA results shows that the only reoccurring parameter is Copper hence it is concluded that Copper is the only component factor that influences the river water quality throughout the period under study. Therefore, it is strongly recommended that any proposed treatment method must be targeted at the removal of copper in addition to other factors of high contributory effects.

This study evaluated the degree of pollution of Ikpoba River due to the incessant discharge of industrial wastewater into the river. The entire study area was digitised and geo-referenced in order to generate the map of the study area as well as the sampling points. Eight (8) water samples were obtained from different locations from the direction of flow of industrial discharge into the river and also within the river. The coordinate of the sample collection points were acquired using handheld geographic positioning system (GPS). Water samples for physicochemical analysis were collected in a clean sterilized plastic container and analysis were carried out in the laboratory following standard procedure. The environmental variables measured were dissolved oxygen (DO), total suspended solid (TSS), pH, total dissolved solid (TDS), turbidity, concentration of nitrate and nitrite, chloride, phosphate, zinc, barium, tin, biological oxygen demand (BOD), conductivity, manganese, magnesium, calcium etc. Results obtained showed that most parameters investigated had increasing values. The calculated water quality index (WQI) from the sampling points ranged from 40.02 to 52.62, which indicates that most of the samples are bad as classified using National Sanitation Foundation (NSF) standard. This study therefore recommends that water quality around areas of industrial wastewater discharge in Ikpoba hill should be monitored and adequate treatment recommended where necessary.

Land farming technique was used to treat hydrocarbon contaminated soil collected from a crude oil spill sites in Edo State, Nigeria. Calibrated standard auger was used to collect soil samples from the site at depth below 30 cm. The samples were characterized and classified. Cow dung and NPK fertilizer were added as additives to complement the nutriments of the soil samples before total petroleum hydrocarbon (TPH) quantification and remediation procedures. Factorial design was applied to vary the input parameters such as pH, mass of substrate, moisture content and turning times of land farming so to ascertain the optimal conditions for the procedure. The result revealed that the in-situ TPH value was 5000 mg kg− 1 on the average and after 90 d of treatment, TPH reduced to 646 mg kg− 1. The turning rate, pH, moisture content and mass of substrate hade 83, 4.36, 0.48 and 0.046% contribution, respectively, for the degradation process using land farming treatment. Numerical optimization techniques applied in the optimum point for land farming input parameters to achieve predicted maximum removal of 99% were evaluated as pH, mass of substrate, moisture content and turning rate to be 6.01, 1 kg, 10% and 5 times in a week, respectively. TPH removed at this optimum point was 98% reducing from 5000 to 636 mg kg− 1. The high coefficient of determination (r2 = 0.9865) as observed in the closeness of predicted and experimental values reflects the reliability of the model and hence, land farming practice with close attention on turning rate as revealed by this study, is recommended for TPH contaminated soil remediation.

The study discussed the remediation potentials of phytoremediation, land farming treatment and chemico-biological stabilization treatments in degrading Total Petroleum Hydrocarbon (TPH) and Polycyclic Aromatic Hydrocarbon (PAH) in soils polluted with crude oil in varying concentrations. The field pilot study was carried out in Benin city, Nigeria by preparing nine (9) cells with sub-cells attached which serve as control; each cell measures 1.53 m2. Three cells contained 100 kg of artificially contaminated soils at low contamination concentration (3000 mg kg-1), the next three cells contained 100 kg of contaminated soil samples but with medium concentration (5000 mg kg-1), while the last three cells contained 100 kg of spike samples in high concentration (7000 mg kg-1). The sub cells contained 10 kg of soil and left untreated. Each role containing three cells with low, medium and high concentration was treated separately using the three treatment methods. Soil samples to organic amendment ratio for the treatments was 2:1. The results showed over 90% reduction in the initial concentration of TPH and PAH across the different contamination levels with except in the control sub cells were only 30% reduction was recorded. The treated soil was found useful for agricultural purpose. One-way analysis of variance reveals a significant difference at p≤0.05 in the results obtained in application of the three methods. This implies that the methods effectively degraded the TPH and PAH concentrations. The three different methods of treatments effectively degraded TPH and PAH contaminants with land farming treatment being the best of the three.

Land farming technique was used to treat hydrocarbon contaminated soil collected from a crude oil spill sites in Edo State, Nigeria. Calibrated standard auger was used to collect soil samples from the site at depth below 30 cm. The samples were characterized and classified. Cow dung and NPK fertilizer were added as additives to complement the nutriments of the soil samples before total petroleum hydrocarbon quantification and remediation procedures. Factorial design was applied to vary the input parameters such as pH, mass of substrate, moisture content and turning times of land farming so to ascertain the optimal conditions for the procedure. The result revealed that the in-situ total petroleum hydrocarbon (TPH) value was 5,000 mg kg-1 on the average and after 90 days of treatment, TPH reduced to 645.907 mg kg-1. The turning rate, pH, moisture content and mass of substrate had 82.79%, 4.36%, 0.48% and 0.046% contributions respectively to the degradation process using land farming treatment. Numerical optimization techniques applied in the optimum point for land farming input parameters to achieve predicted maximum removal of 98.60% were evaluated as pH, mass of substrate, moisture content and turning rate to be 6.01, 1 kg, 10% and 5 times in a week respectively. TPH removed at this optimum point was 97.83% reducing from 5,000 to 635.907 mg kg-1. The high coefficient of determination (r2 = 0.9865) as observed in the closeness of predicted and experimental values reflects the reliability of the model and hence, land farming practice with close attention on turning rate as revealed by this study, is recommended for TPH contaminated soil remediation.