The geometry, frontier molecular orbitals (FMOs), vibrational, NBO analysis, and molecular docking simulations of aflatoxins (B1, B2, M1, M2, G1, G2), zearalenone (ZEA) emodin (EMO), alternariol (AOH), alternariol monoethyl ether (AMME), and tenuazonic acid (TeA) mycotoxins have been extensively theoretically studied and discussed based on quantum density functional theory calculations using Gaussian 16 software package. The theoretical computation for the geometry optimization, NBOs, and the molecular docking interaction was conducted using Density Functional Theory with B3LYP/6-31+G(d,p), NBO program, and AutoDock Vina tools respectively. Charge delocalization patterns and second-order perturbation energies of the most interacting natural bond orbitals (NBOs) of these mycotoxins have also been computed and predicted. Interestingly, among the mycotoxins investigated, aflatoxin G1 is seen to give the strongest stabilization energy while Zearalenone shows the highest tendency to accept electron(s) and emodin, an emerging mycotoxin gave the best binding pose within the androgen receptor pocket with a mean binding affinity of -7.40 kcal/mol.

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ABSTRACT:The paper is aimed at the investigation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils collected at depths of 15 to 100cm from two spilled sites in the vicinity of a leaking pipeline (Calabar, Nigeria). The soils were prepared in the laboratory using standard procedure and were analyzed for sixteen priority PAHs using Gas Chromatography -Mass Spectrophotometer (GC -MS).The concentration of total PAHs (TPAHs) in the contaminated soils ranged from 4.28 to 29.77mg/Kg and decreased with depth. These levels are higher than values obtained from rural and semi urban soils but lower than values obtained from soils in the vicinity of some petroleum handling facilities in part of the study area. Generally the soils were relatively enriched with medium-and lower-molecular-weight PAHs. Phenanthrene/Anthracene, Fluoranthene/Pyrene, Fluorantine/Fluorantine+Pyrene and Benzo(A)Anthracene/Chrysene ratios and the relative abundance of PAHs according to the number of rings were used to access the sources of PAHs. In addition, the main mechanism of PAHs transport in the study area was proposed. © JASEM http://dx.doi.org/10.4314/jasem.v18 i2.23

The ground water quality of Okobo Local Government Area was investigated. Sixteen boreholes (BHs) water samples were collected from four zones (Okopedi, Ekeya, Ukwong and Okiuso) in Okobo. Standard analytical procedures were used to analyze the physicochemical, bacteriological and heavy metal parameters in the water samples and the results compared to Nigerian standard for drinking water quality (NSDWQ). some physicochemical parameters investigated were within the acceptable limits set by NSDWQ except pH (5.99 ± 0.37), DO (0.31 ± 0.06) mg/L, BOD5 (6.26 ± 0.4) mg/L and Nitrate (62.53 ± 5.96) mg/L. Bacteriological parameter like fecal coliform (128.69 ± 31.40) MPN/100 mL and total coliform (287.63 ± 40.31) MPN/100 mL were also above the limits set by NSDWQ implying organic pollution due to fecal contamination. Heavy metals were also within the acceptable limit except Lead (0.1 ± 0.1) mg/L, Chromium (0.4 ± 0.2) mg/L, and Manganese (0.16 ± 0.2) mg/L which were slightly above acceptable limits in all the zones. Water quality index calculation results grouped the BHs into; BH7 (26–50) very good; BH1, BH3, BH4, BH8, BH11, BH14, and BH16 (51–75) poor; BH2, BH5, BH6, BH9, BH12, BH13 and BH15 (76–100) very poor and BH 10(> 100) unsuitable for drinking. Pearson coefficient correlation, principal component analysis (PCA) and cluster analysis (CA) were used to establish interrelationship among the parameters, common sources of the pollutants and grouping of the BHs affected by these pollutants. PCA extracted six principal components (PCs) from the investigated parameters in the BHs, with sources of pollution either natural mineral or anthropogenic source. CA grouped all the sixteen BHs investigated into three clusters with various levels of contamination from pollutant sources. Consequently, the polluted BHs require treatment using high test hypochlorite (HTH) as the pollutant common to all the BHs is mostly bacterial pollutant; moreover, BHs should be sited 15 m away from septic tank or latrine to reduce contamination from coliform.

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