Study on the downward movement of carbofuran in two Malaysian soils

The downward movement of carbofuran in two Malaysian soil types was studied using soil columns. The columns were filled with disturbed and undisturbed soils of either the Bagan Datoh soil (clay) or the Labu soil (sandy clay). The average total percentage of carbofuran in the leachate of the undisturbed Labu soil after 14 days of watering (80.8%) was approximately similar to that of the total amount from the disturbed soil (81.4%). However, carbofuran leaching was observed in the disturbed soil after the fourth day of watering whereas for the undisturbed soil, leaching occurred after the first watering. A similar trend was observed in the Bagan Datoh soil where the residue of carbofuran was detected after the first day of watering in the undisturbed soil column but only at the eighth day of watering in the disturbed soil column. The total percentage carbofuran in the leachate of disturbed and undisturbed soil columns from Bagan Datoh after 14 days of watering was 3.6% and 41.7%, respectively. The study showed that less leaching occurred in soil columns with high organic content such as the Bagan Datoh soil and especially so in disturbed soils where the organic matter was homogeneously mixed in all layers

Adsorption and desorption of glufosinate ammonium in soils cultivated with oil palm in Malaysia

In Malaysia, glufosinate ammonium (GLUF) is a commonly used herbicide in oil palm plantations to control broad-leaved weeds and grasses. Adsorption and desorption of (GLUF) were studied using the batch equilibrium technique in four mineral soils, Inceptisols (Selangor), Oxisols (Munchong) and Ultisols (Serdang and Rengam) series and peat (Histosols) collected under oil palm cultivation from 0-15 cm and 15-30 cm depths. Adsorption coefficients of the herbicide were correlated with soil properties i.e. organic matter content, clay content, cation exchange capacity (CEC) and pH. The concentrations of GLUF used were (0, 0.25, 0.5, 1, 1.5, 3, 5 and 10 μg/mL). The adsorption and desorption isotherms were fitted using linear and Freundlich equations. Adsorption of GLUF was in the following order: Selangor > Rengam> Munchong> peat > Serdang. The results indicate that the adsorption of GLUF is positively correlated only with clay content. The high sorption of the Selangor soil could be explained by the high clay content in Selangor series soil compared to the other soil series. However, the order of GLUF desorption was in the following order: Serdang> peat> Munchong> Rengam> Selangor. Results indicate that adsorption of GLUF was mainly on the clay fraction of the soil and the binding strength of adsorbed GLUF was high as indicated by the order of GLUF desorption from the soils

Monitoring the change patterns of physicochemical properties of oil blend as function of storage time.

The aim of this study was to investigate the effect of storage time, type and concentration level of frying oil on the physicochemical properties of oil blend during 8 consecutive week storage. The physicochemical properties of frying media, namely melting point, iodine value (IV), peroxide value (PV), anisidine value (AV), TOTOX value (TV) and free fatty acids (FFA), were considered as response variables. The results obtained from PV, AV and TV measurements indicated that the oil blend containing higher content of linolenic acid (C18:2) and lower percentage of oleic acid (C18:1) showed less stability to the oxidation. This was explained by the higher chemical stability of oleic acid towards oxidation both at ambient and elevated temperatures compared to polyunsaturated fatty acids. The prepared oil blends (POO:OO, 75:25 and 50:50) indicated higher PV (> 1.64 meq O2/kg) compared to control sample PV (0.8 meq O2/kg) in Week 0 of storage, while the increase in PV of control sample was found to be sharper compared to the prepared oil blends. In fact, the oil blend containing higher content of linolenic acid (C18:2) and lower percentage of oleic acid (C18:1) showed less stability to the oxidation. Thus, the sharper increase in PV of control sample was largely contributed to the high amount of linolenic acid. During 8 weeks storage, the melting point of control and oil blends (POO:OO, 75:25 and 50:50) increased, from 21.40 to 22.45, from 18.27 to 21.72 and from 14.51 to 19.41ºC, respectively. Thus, the highest and least changes in melting points were shown by oil Blend 2 (POO:OO, 50:50) and control sample. In most cases, the main effect of storage time and the interaction effect of storage time and type of frying oil showed the most significant (p < 0.05) effect and the least significant (p < 0.05) effect on physicochemical properties of frying media, respectively. This study suggests that the chemical stability of frying oil during storage depends not only on the saturated fatty acid content but also on the concentration level of monounsaturated and polyunsaturated fatty acids

Extraction and physicochemical properties of low free fatty acid crude palm oil.

Response surface methodology was applied to optimize the pre-treatment of oil palm (Elaeis guineensis) fruit spikelets before oil extraction. The treatment applied was drying at different times and temperatures. The dried spikelets were then subjected to mechanical processes and crude oil was extracted. A central composite design was employed to study the responses, namely percentage of free fatty acids (FFA) and oil yield, and the optimum conditions for minimum FFA and maximum oil yield were identified from their respective contour plots. It was concluded that the pre-treatment should be carried out for 12.8 h at 66.8 °C. Under the optimum conditions, the corresponding response values for FFA and oil yield were 1% and 33.6%, respectively. Some of the physicochemical properties of the extracted oil were then determined. The low free fatty acid crude palm oil exhibited good physicochemical properties and could be useful for industrial applications

Changes in oxidation indices and minor components of low free fatty acid and freshly extracted crude palm oils under two different storage conditions

This article reports on the changes of oxidation indices and minor components of low free fatty acid (FFA) and freshly extracted crude palm oils after storage at ambient (28 ± 1 C) and 60 C for 77 days. The changes in peroxide value (PV), FFA, extinction coefficient at 233 and 269 nm (K 233 and K 269), bleachability index (DOBI), carotene and vitamin E contents were monitored. PV, FFA, K 233 and K 269 of both oil samples increased as storage progressed while the values of carotene and vitamin E contents decreased. At the end of storage period at 60 °C, the carotene content of low FFA crude palm oil was 4.24 ppm. The storage conditions used led to the loss of entire vitamin E fractions of both oil samples as well as a reduction in DOBI values except for freshly extracted crude palm oil stored at ambient temperature

Dioxin/furan level in the Malaysian oil palm environment

Environmental samples collected from oil palm premises were evaluated for dioxins/furans contamination. The samplings were carried out at oil palm premises located in Banting (Premise A) and in Teluk Intan (Premise B), involving two environmental matrices namely ambient air and soil. The soil samples were collected in the plantations while ambient air samples were collected in the vicinity of the mills and refineries. The results of the analyses showed that the level of dioxins/furans in ambient air were generally higher in oil palm premise located adjacent to industrial establishments. The concentration levels at premise A mill and refinery located adjacent to industrial establishments, ranged from 64.14 WHO–TEQ fg m-3 to 131.87 WHO–TEQ fg m-3, while for premise B mill and refinery located in the rural area, ranged from 9.93 WHO–TEQ fg m-3 to 16.66 WHO–TEQ fg m-3. Meanwhile for soil samples, the highest concentrations were recorded in soil collected near roads used heavily by vehicles. The concentration levels of soil samples collected at premise A and premise B plantations ranged from 1.910 WHO-TEQ pg g-1 dry weight to 3.305 WHO-TEQ pg g-1 dry weight