Adsorption of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from water using leaf biomass (Vitis vinifera) in a fixed-bed column study.

INTRODUCTION: Adsorption of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) onto modified activated carbons (AC-H3PO4) produced from leaf biomass of Vitis vinifera leaf litter in a fixed bed column experiment was investigated in this study. METHODS: The column bed was packed with the produced activated carbons in a uniform particle size of ˃ 64 µm. Experimental parameters including the initial concentration of the solution, column bed height, the mass of adsorbent and flow rate were optimized to establish the best adsorption efficiency parameters for the system. Breakthrough and saturated time were estimated from the column fixed bed experimental data and analysed using the Adam-Bohart, Thomas model, and Yoon-Nelson models. RESULTS: Maximum sorption capacities of produced activated carbon ACH3PO4 based on Thomas model were 159.61 and 208.64 mg/g for PFOA and PFOS, respectively. The results indicated the breakthrough and saturated time of the system increased concurrently with the increase in bed height and initial concentrations, while an increase in flow rate enhanced fractional bed utilization (FBU) efficiency of the column. Thomas and Yoon-Nelson model best describe the prediction of breakthrough data and sorption behaviour of PFOA and PFOS indicating suitability of AC-H3PO4 column design. CONCLUSION: Findings suggest that agro based adsorbent is a good alternative to non-ago based adsorbent. The surface characteristics of the phosphoric acid modified activated carbons AC-H3PO4 affirmed the removal of PFOA and PFOS from the contaminated water.

Accumulation and risk assessment of metals in palm oil cultivated on contaminated oil palm plantation soils.

Anthropogenically polluted soils with metals are detrimental to human life. The present study assessed the concentration of metals in soil and the risks associated with the consumption of the metals when transferred from soil to palm oil. The metals of interest were Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn. Analysis was done on metals in soil and virgin palm oil from fifteen independent sampling locations in the southern states of Nigeria, which includes the Nigeria Institute for Oil Palm Research (NIFOR) and its substations. Top soils were collected at a depth of 0-15 cm and virgin palm oil in 1 litre container by grab sampling method. The method proposed was to achieve high throughput with minimal mobile phase solvent. Micro emulsion technique was involved as sample preparation method for the extraction of metals in virgin palm oil from the matrix. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used to analyse metals in virgin palm oil and soil. This reduces analysis time and does not require complex sample preparation. Zinc metal recorded the highest concentration of metal in the palm oil and Chromium metal recorded the highest concentration of metal in soil. There was a correlation between the accumulations of metals from soil to palm oil. Risk was assessed using various indices. Cadmium metal recorded the highest concentration in the Target Hazard Quotient (THQ), Accumulation Factor (AF) and Health Risk Index (HRI). Daily Intake of Metals (DIM) was highest for Chromium metal. Cadmium was the highest accumulator of metals in the palm oil.

Validation and determination of nine PFCS in surface water and sediment samples using UPLC-QTOF-MS.

In this study, an analytical method for the routine determination of nine perfluorinated compounds (PFCs), using ultra performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (UPLC-QTOF-MS), was developed, validated, and used for their assay in surface water and sediments. The method yielded good linearity with a correlation coefficient (R2) ranging between 0.991 and 0.999 for all the compounds investigated. Limits of detection (LOD) ranged between 0.02 and 0.08 ng/l, while the limit of quantification (LOQ) ranged from 0.065 to 0.261 ng/l. Recovery studies were carried out in replicate assays, and percentage recoveries ranged between 56 and 112% for the nine perfluorinated compounds investigated. The method was applied to determine levels of perflurooctanoic acid (PFOA) and PFOS in surface water and sediment samples collected along the Plankenburg River in Stellenbosch, South Africa. Samples were pre-treated, extracted, and cleaned up via offline solid-phase extraction (SPE) procedures, using hydrophilic-lipophilic balance (HLB) C-18 cartridges. Levels of PFOA and PFOS found in surface water ranged between (12.8 ± 4.24 and 62.62 ± 4.86 ng/l) and (

Levels of organochlorine pesticide residues in marine-, surface-, ground- and drinking waters from the Eastern Cape Province of South Africa.

Persistent organochlorine pesticides (OCPs) such as DDT and its metabolites (DDDs and DDEs). chlordane, hexachlorobenzene (HCB), heptachlor and endosulfan were determined in drinking-, ground-, surface- and marine waters from the Eastern Cape Province of South Africa. Percentage recoveries of the OCPs from spiked river water ranged from 71.03 +/- 8.15% (dieldrin) to 101.25 +/- 2.17% (alpha-BHC). The levels of OCPs ranged from 5.5 ng/L (2,4-DDD) to 160 ng/L (HCB) in the water samples. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulfan and chlordane were detected.

Methods for selective determination of persistent organochlorine pesticide residues in water and sediments by capillary gas chromatography and electron-capture detection.

Different extraction methods were evaluated for the determination of fifteen organochlorine pesticides (OCPs) in water and sediments. Liquid-liquid extraction (LLE) was evaluated for the pesticides analyses in water while Soxhlet extraction (SE) and microwave assisted extraction (MAE) methods were compared in sediment. Of all the extracting solvents used, dichloromethane gave the best results. Percentage recoveries ranged from 71.03 +/- 8.15 (dieldrin) to 101.25 +/- 2.17% [a-benzenehexachloride (alpha-BHC)] in water with LLE. In sediments the percentage recoveries with Soxhlet extraction method varied between 88.22 +/- 7.85 (endrin) and 109.63 +/- 5.10% (beta-BHC) and ranged from 74.11 +/- 9.82 (2,4 DDT) to 97.50 +/- 4.56% (alpha-BHC) with MAE. The limits of detection for the OCPs ranged from 5.5 to 20.6 ng/l and between 0.6 and 2.1 ng/g. respectively. The LLE and the SE methods were applied to water and sediments samples, respectively, from marine and freshwater sources in the Eastern Cape Province of South Africa that receive runoffs from agricultural lands and effluents from industries. The levels of OCPs ranged from 5.5 (2,4-DDD) to 450 +/- 0.10 ng/l (beta-BHC) in water samples and from 0.6 (aldrin and 2,4-DDD) to 184 +/- 0.12 ng/g (beta-BHC) in sediments for triplicate analyses. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulphan and the chlordanes were detected.

Determination of cadmium and lead in urine of some Nigerian subjects.

Forty-one urine samples of smokers and non-smokers from Ile-Ife, Nigeria were analyzed for normal cadmium and lead levels after acid digestion. Results of the preliminary study show that concentrations of cadmium obtained were generally low compared with lead. The mean urinary levels from non-smokers ranged from 0.05 - 0.02 to 0.16 - 0.01 wg ml-1 and from 0.02 - 0.03 to 0.88 - 0.04 wg ml-1 for cadmium and lead respectively, whilst, for smokers, urinary levels varied between 0.07 - 0.01 and 0.23 - 0.02 wg ml-1 and between 0.28 - 0.03 and 1.02 - 0.02 wg ml-1 were obtained for cadmium and lead, respectively. Cd levels in urine of smokers and non-smokers are higher than the recommended normal level of 0.0085 wg ml-1, while levels of Pb are above the 0.08-0.15 wg ml-1 exposure range. Results of spiking experiments with urine gave high percentage recoveries for both elements (Cd, 87.9 - 0.40%) and (Pb, 90.40 - 0.12%). Blank determination was done for background correction.

Production of oxalic acid by some fungi infected tubers.

Oxalic acid (as oxalate) was detected in four tubers commonly used for food in Nigeria-Dioscorea rotundata (White yam), Solanum tuberosum (Irish potato), Ipomoea batatas (Sweet potato), and Manihot esculenta (cassava). Whereas healthy I. batata had the highest oxalic acid content, healthy M. esculenta contained the lowest. When all tubers were artifically inoculated with four fungi-Penicillium oxalicum CURIE and THOM, Aspergillus niger VAN TIEGH, A. flavus and A. tamarii KITA, there was an increase in oxalate content/g of tuber tissue. The greatest amount of oxalate was produced by P. oxalicum in D. rotundata tuber. Consistently higher amounts of oxalate were produced by the four fungi in infected sweet potato tuber than in any other tuber and consistently lower amounts of oxalate were produced by the four fungi in Irish potato tuber. Differences in the carbohydrate type present in the tubers and in the biosynthesis pathway are thought to be responsible for variation in the production of oxalate in the different tubers by the four fungi used.