Ismail Sahid

Pesticide risk assessment: A study on inhalation and dermal exposure to 2,4-D and paraquat among Malaysian paddy farmers

A cross-section analytical study was conducted to evaluate the risk of pesticide exposure to those applying the Class II pesticides 2,4-D and paraquat in the paddy-growing areas of Kerian, Perak, Malaysia. It investigated the influence of weather on exposure as well as documented health problems commonly related to pesticide exposure. Potential inhalation and dermal exposure for 140 paddy farmers (handlers of pesticides) were assessed. Results showed that while temperature and humidity affected exposure, windspeed had the strongest impact on pesticide exposure via inhalation. However, the degree of exposure to both herbicides via inhalation was below the permissible exposure limits set by United States National Institute of Occupational Safety and Health (NIOSH). Dermal Exposure Assessment Method (DREAM) readings showed that dermal exposure with manual spraying ranged from moderate to high. With motorized sprayers, however, the level of dermal exposure ranged from low to moderate. Dermal exposure was significantly negatively correlated with the usage of protective clothing. Various types of deleterious health effects were detected among users of manual knapsack sprayers. Long-term spraying activities were positively correlated with increasing levels of the gamma-glutamyl transpeptidase (GGT) liver enzyme. The type of spraying equipment, usage of proper protective clothing and adherence to correct spraying practices were found to be the most important factors influencing the degree of pesticide exposure among those applying pesticides.

Degradation of two acetanilide herbicides in a tropical soil

The acetanilide herbicides alachlor and metolachlor are registered for control of most annual grasses and certain broadleaf weeds in many crops such as corn (Zea mays L. ), soybean (Glycine max [L.] Merr.), rice (Oryza sativa L.), and peanut (Arachis hypogaea L.) (WSSA 1989). In Malaysia, these two herbicides are used for weed control in corn and peanut. While much is known about their activity and mode of action, little quantitative information is available concerning their mode of dissipation from soils under Malaysian conditions. The primary factors affecting soil degradation of acetanilide herbicides are adsorption and microbial decu,~osition, with 90% of the loss attributable to the latter (WSSA 1989). Adsorption and bioactivity of the acetanilide herbicides were correlated with organic matter, clay content and other soil parameters ( Weber and Peter 1982). Organic matter was the primary adsorbing surface in the soil ( Rahman et al. 1978; Weber and Peter 1982; Nishimoto and Rahman 1985). Propachlor and alachlor were found to be about 50 times more persistent in sterile soil than in non-sterile soil (Beestman and Deming 1974). Alachlor could be degraded by a cu,~n soil fungi Chaetcmi~n globos~n (Tiedje and Hagedorn 1975). Because acetanilide herbicides are degraded quickly by soil microbes, their soil half-lives are relatively short. Beestman and Deming (1974) found half-lives of 4.0 and 7.3 days for alachlor and 1.9 and 4.4 days for propachlor in a silt and a silty-clay soil, respectively. The half-life of metolachlor has bees estimated between 30 and 50 days in the northern areas and 15 to 25 days in the southern areas of the United States depending on soil type, moisture and temperature (WSSA 1989). No reports are known to exist on the persistence of these herbicides in tropical soils. Therefore, experiments were conducted to determine the degradation of alachlor and metolachlor in the soil at various moisture levels and in a field to be planted with corn and peanut. Send reprints requests to Ismail Sahid at the above address.

Determination of the herbicide fluroxypyr in oil matrices

The purpose of this study was to develop a method for the determination of fluroxypyr (4-amino-3,5-dichloro-6-fluro2-pyridyloxyacetic acid) residue in palm oil namely crude palm oil (CPO) and crude palm kernel oil (CPKO). The method involves the extraction of the herbicide from the oil matrix followed by low temperature precipitation and finally quantification of the residues using the high performance liquid chromatography (HPLC). The extraction efficiency of the method was evaluated by conducting recovery studies. The recovery of fluroxypyr from the fortified CPO samples ranged from 78%–111% with the relative values for the coefficient of variation ranging from 1.4 to 8.6%. Furthermore, the recovery of fluroxypyr from the spiked CPKO samples ranged from 91–107% with the relative values for the coefficient of variation ranging from 0.6 to 4.5%. The minimum detection limit of fluroxypyr in CPO and CPKO was 0.05 μg/g. The method was used to determine fluroxypyr residues from the field-treated samples of CPO and CPKO. When fluroxypyr was used for weed control in oil palm plantations no residue was detected in CPO and CPKO irrespective of the sampling interval and the dosage applied at the recommended or double the manufacturers recommended dosage.

Molecular basis for resistance to ACCase-inhibiting fluazifop in Eleusine indica from Malaysia

Eleusine indica (goosegrass) populations resistant to fluazifop, an acetyl-CoA carboxylase (ACCase: EC6.4.1.2)-inhibiting herbicide, were found in several states in Malaysia. Dose-response assay indicated a resistance factor of 87.5, 62.5 and 150 for biotypes P2, P3 and P4, respectively. DNA sequencing and allele-specific PCR revealed that both biotypes P2 and P3 exhibit a single non-synonymous point mutation from TGG to TGC that leads to a well known Trp-2027-Cys mutation. Interestingly, the highly resistant biotype, P4, did not contain any of the known mutation except the newly discovered target point Asn-2097-Asp, which resulted from a nucleotide change in the codon AAT to GAT. ACCase gene expression was found differentially regulated in the susceptible biotype (P1) and highly resistant biotype P4 from 24 to 72h after treatment (HAT) when being treated with the recommended field rate (198gha(-1)) of fluazifop. However, the small and erratic differences of ACCase gene expression between biotype P1 and P4 does not support the 150-fold resistance in biotype P4. Therefore, the involvement of the target point Asn-2097-Asp and other non-target-site-based resistance mechanisms in the biotype P4 could not be ruled out.

Effects of watering frequency, shade and glyphosate application on Paspalum conjugatum Berg (sour grass)

Abstract Greenhouse experiments were conducted to determine effects of shade, water and a combination of either watering frequency or shade and glyphosate on growth of Paspalum conjugatum Berg. (sour grass). Plant height, shoot and root dry weight and numbers of leaves and tillers decreased as light and water levels decreased. The combined effect of glyphosate application and reduced watering frequency influenced shoot and root growth of plants receiving daily watering. Glyphosate had less effect on shoot and root dry weight and injury ratings of sour grass grown under water stress. Reduction in the growth of sour grass treated with 0.2 kg/ha glyphosate was greater under shade (52% and 69%) than under exposed conditions (0% and 36% shade). Visible injury to sour grass with 0.05 kg/ha glyphosate was greater under 69% shade than under exposed conditions.

Determination of hexaconazole in field samples of an oil palm plantation

In oil palm plantations, the fungicide hexaconazole is used to control Ganoderma infection that threatens to destroy or compromisethe palm. The application of hexaconazole is usually through soil drenching, trunk injection, or a combination of these two methods. It is therefore important to have a method to determine the residual amount of hexaconazole in the field such as in samples of water, soil, and leaf to monitor the use and fate of the fungicide in oil palm plantations. This study on the behaviour of hexaconazole in oil palm agro-environment was carried out at the UKM-MPOB Research Station, Bangi Lama, Selangor. Three experimental plots in this estate with 7-year-old Dura x Pisifera (DxP) palms were selected for the field trial. One plot was sprayed with hexaconazole at the manufacturers recommended dosage, one at double the recommended dosage, and the third plot was untreated control. Hexaconazole residues in the soil, leaf, and water were determined before and after fungicide treatment. Soil samples were randomly collected from three locations at different depths (0-50 cm) and soil collected fromthe same depth were bulked together. Soil, water, and palm leaf were collected at -1 (day before treatment), 0 (day of treatment), 1, 3, 7, 14, 21, 70, 90, and 120 days after treatment. Hexaconazole was detected in soil and oil palm leaf, but was not detected in water from the nearby stream.

Life cycle inventory of oil palm lumber production: A gate-to-gate case study

Life Cycle Assessment (LCA) has been applied in the Malaysian oil palm industry since 2010. It is important to ensure that this main industry is ready to meet the demands and expectations of European market on the environmental performance of the oil palm industry. In addition, oil palm biomass, especially oil palm trunk (OPT) are abundantly available after replanting every year. In order to maximize the usage of OPT as a green product, it can be converted to palm lumber as a value-added product. Palm lumber act as a basis product from OPT before it is converted to panel product such as plywood, sandwich board and so on. However, the LCA study on palm lumber production is still scarce in Malaysia. Hence, this paper aims to perform and collect the inventory data for palm lumber production, which is known as Life Cycle Inventory (LCI). A gate-to-gate system boundary and the functional unit of 1 m3 of palm lumber produced have been used in this study. This inventory data was collected from three batches of the production cycle. The inputs are mainly the raw materials which are the OPT and the energy from diesel and electricity from the grid. Generally, each consumption of input such as energy and fossil fuel were different at each stage of palm lumber production. Kiln-drying represents a prominent stage in terms of energy consumption, which electrical use in the dryer represents 94% of total electrical grid consumption as compared to another stage of palm lumber production. By adding the inventory information especially in the downstream sector of biomass industry, hopefully it can improve the sustainability of oil palm industry in Malaysia.Life Cycle Assessment (LCA) has been applied in the Malaysian oil palm industry since 2010. It is important to ensure that this main industry is ready to meet the demands and expectations of European market on the environmental performance of the oil palm industry. In addition, oil palm biomass, especially oil palm trunk (OPT) are abundantly available after replanting every year. In order to maximize the usage of OPT as a green product, it can be converted to palm lumber as a value-added product. Palm lumber act as a basis product from OPT before it is converted to panel product such as plywood, sandwich board and so on. However, the LCA study on palm lumber production is still scarce in Malaysia. Hence, this paper aims to perform and collect the inventory data for palm lumber production, which is known as Life Cycle Inventory (LCI). A gate-to-gate system boundary and the functional unit of 1 m3 of palm lumber produced have been used in this study. This inventory data was collected from three batches of t...

Heavy metals accumulation in parts of paddy Oryza sativa L. grown in paddy field adjacent to ultrabasic soil

The present study was carried out to evaluate the accumulation and translocation of heavy metals from soil around the root zone to various parts of the paddy plant, namely the roots, stems, leaves and rice grains. This study was conducted in 2014 in paddy field adjacent to ultrabasic soil (field 1 and 2) located in Ranau, Sabah and one field (Field 3) taken as control located at the UKM experimental plot in peninsular of Malaysia. The plant species used in the present investigation is Paddy Batu. The heavy metals studied were Chromium (Cr), Iron (Fe) and Nickel (Ni). Heavy metals in soil and plant were extracted by wet digestion method. Heavy metals present in paddy plants and soils extract were measured using the ICP-MS. Heavy metals concentrations in the plant parts in descending order is the root > leaves > stem > rice grain. Lower concentration of all heavy metals in soils and plant parts was shown by the control site (Field 3) in UKM Bangi. Higher concentration of heavy metals occurred in the roots c...

Effects of zinc oxide nano-particles on groundnut (Arachis hypogaea) seedlings

Along with the rapid growth of nanoparticle consumption in various industries, concerns about the unknown effects caused by the presence of these materials in the natural environment and agricultural systems are being highlighted. Due to the growing trend of Nano Zinc Oxide Nanoparticle (ZnO-np) which is one of the most widely used nanoparticles being released into the environment, it has attracted the attention for more studies to be done on the effects of this nanoparticle on organisms. This study was carried out to investigate the phytotoxicity effect of ZnO-np on peanut seedlings in Murashige and Skoog medium (MS medium). The experimental treatments of this study include nine concentrations of ZnO-np (0, 10, 30, 50, 100, 200, 400, 1000, 2000 ppm) added to MS medium. Peanut seedlings were incubated for 3 weeks in optimum condition and after that, seedling characteristics such as length, wet and dry weight of root and shoot were measured and the water content of root and shoot were calculated. Results o...

Life cycle inventory for palm based plywood: A gate-to-gate case study

The oil palm industry heavily relies on the world market. It is essential to ensure that the oil palm industry is ready to meet the demands and expectation of these overseas customers on the environmental performance of the oil palm industry. Malaysia produces 13.9 million tons of oil palm biomass including oil palm trunk (OPT), frond and empty fruits bunches (EFB) annually. OPT felled in some oil palm plantations during replanting is transported to various industries and one such industry is the plywood factories. In order to gauge the environmental performance of the use of OPT as plywood a Life Cycle Assessment (LCA) study was conducted for palm based plywood. LCA is an important tool to assess the environmental performance of a product or process. Life cycle inventory (LCI) is the heart of a LCA study. This LCI study has a gate-to-gate system boundary and the functional unit is 1 m3 palm plywood produced and covers three types of plywood; Moisture Resistance Plywood (MR), Weather Boiling Proof Plywood...