A heavy-metal assay has been developed using bromelain, a protease. The enzyme is assayed using casein as a substrate with Coomassie dye to track completion of hydrolysis of casein. In the absence of inhibitors, casein is hydrolysed to completion, and the solution is brown. In the presence of metal ions such as Hg2+ and Cu2+, the hydrolysis of casein is inhibited, and the solution remains blue. Exclusion of sulfhydryl protective agent and ethylenediaminetetraacetic in the original assay improved sensitivity to heavy metals several fold. The assay is sensitive to Hg2+ and Cu2+, exhibiting a dose-response curve with an IC50 of 0.15 mg 1(-1) for Hg2+ and a one-phase binding curve with an IC50 of 0.23 mg 1(-1) for Cu2+. The IC50 value for Hg2+ is found to be lower to several other assays such as immobilized urease and papain assay, whilst the IC50 value for Cu2+ is lower than immobilized urease, 15-min Microtox, and rainbow trout.
The control of filariasis vectors has been enhanced in several areas, but there are main challenges, including increasing resistance to insecticides and lack of cheap and eco-friendly products. The toxicity of iron (Fe0) and iron oxide (Fe2O3) nanoparticles has been scarcely investigated yet. We studied the larvicidal and pupicidal activity of Fe0 and Fe2O3 nanoparticles against Culex quinquefasciatus. Fe0 and Fe2O3 nanoparticles produced by green (using a Ficus natalensis aqueous extract) and chemical nanosynthesis, respectively, were analyzed by UV-Vis spectrophotometry, FT-IR spectroscopy, XRD analysis, SEM, and EDX assays. In larvicidal and pupicidal experiments on Cx. quinquefasciatus, LC50 of Fe0 nanoparticles ranged from 20.9 (I instar larvae) to 43.7 ppm (pupae) and from 4.5 (I) to 22.1 ppm (pupae) for Fe2O3 nanoparticles synthesized chemically. Furthermore, the predation efficiency of the guppy fish, Poecilia reticulata, after a single treatment with sub-lethal doses of Fe0 and Fe2O3 nanoparticles was magnified. Overall, this work provides new insights about the toxicity of Fe0 and Fe2O3 nanoparticles against mosquito vectors; we suggested that green and chemical fabricated nano-iron may be considered to develop novel and effective pesticides.
A new cloud point methodology was successfully used for the extraction of carcinogenic pesticides in milk samples as a prior step to their determination by spectrophotometry. In this work, non-ionic silicone surfactant, also known as 3-(3-hydroxypropyl-heptatrimethylxyloxane), was chosen as a green extraction solvent because of its structure and properties. The effect of different parameters, such as the type of surfactant, concentration and volume of surfactant, pH, salt, temperature, incubation time and water content on the cloud point extraction of carcinogenic pesticides such as atrazine and propazine, was studied in detail and a set of optimum conditions was established. A good correlation coefficient (R2 ) in the range of 0.991-0.997 for all calibration curves was obtained. The limit of detection was 1.06 µg l-1 (atrazine) and 1.22 µg l-1 (propazine), and the limit of quantitation was 3.54 µg l-1 (atrazine) and 4.07 µg l-1 (propazine). Satisfactory recoveries in the range of 81-108% were determined in milk samples at 5 and 1000 µg l-1, respectively, with low relative standard deviation, n = 3 of 0.301-7.45% in milk matrices. The proposed method is very convenient, rapid, cost-effective and environmentally friendly for food analysis.
The main goal of this research work is to measure the concentration levels of organochlorine residue in soil. The potential health risk of this pollutant on human was also determined. 10 samples were taken from a lowland paddy field situated in Kelantan, Malaysia. Physical parameters namely soil pH, organic carbon content, water content and particle size were identified to evaluate the quality of soil from the agriculture site. Soxhlet extraction and florisil clean-up process were applied to isolate 10 targeted organochlorine compounds prior to the final determination using a gas chromatography-electron capture detector. Soil from the lowland has characteristics such as slightly acidic, low organic carbon content, high water content and texture dominated by the sandy type. Concentration levels of six detected organochlorine pesticides were calculated in µg/kg. Hazard quotient value in all samples was less than the acceptable risk level HQ ≤ 1, thus reflecting the status of soil in the subjected area as unlikely to pose any adverse health effects.
Rice fields are traditional landscape in Malaysia that sustains various species of birds .Waterbirds, raptors, Passeriformes and Columbiformes were observed and counted using point count method at rice fields in Bandar Baharu, Kedah from March 2009 to February 2010. The current status of birds in the rice fields of Malaysia has not been widely researched. The objective of this study was to document the bird species richness and diversity and temporal bird distribution during the annual rice growing cycle. There were 5120 birds representing 67 species belonging to 29 families being recorded. The diversity index (Shannon-Wiener) varied monthly between 2.154 and 3 .321 . The most abundant bird family observed was Ardeidae (29.09%), followed by Sturnidae ( 10.15%) and Hirundinidae (7.86%). Rice growing seasons involve three main stages; direct seedling/transplanting, growing and harvesting. Each stage attracts different bird species to exist in the rice field and surrounding areas. Statistical analysis showed the alternative hypothesis that states abundance of bird species is different monthly was accepted (F1124= 3.033, p< 0.05). Farming activities and rice growing seasons regularly influenced birds' presence in the rice fields and attracted different bird species. Reclamation and urban development on the rice fields is a major concern. Conservation efforts and strict regulation of pesticide use should be implemented to develop sustainable agriculture practices that are beneficial to human and wildlife communities.
Photocatalysis is an ecofriendly technique that emerged as a promising alternative for the degradation of many organic pollutants. The weaknesses of the present photocatalytic system which limit their industrial applications include low-usage of visible light, fast charge recombination, and low migration ability of the photo-generated electrons and holes. Therefore, various elements such as noble metals and transition metals as well as non-metals and metalloids (i.e., graphene, carbon nanotube, and carbon quantum dots) are doped into the photocatalyst as co-catalysts to enhance the photodegradation performance. The incorporation of the co-catalyst which alters the photocatalytic mechanism was discussed in detail. The application of photocatalysts in treating persistent organic pollutants such as pesticide, pharmaceutical compounds, oil and grease and textile in real wastewater was also discussed. Besides, a few photocatalytic reactors in pilot scale had been designed for the effort of commercializing the system. In addition, hybrid photocatalytic system integrating with membrane filtration together with their membrane fabrication methods had also been reviewed. This review outlined various types of heterogeneous photocatalysts, mechanism, synthesis methods of biomass supported photocatalyst, photocatalytic degradation of organic substances in real wastewater, and photocatalytic reactor designs and their operating parameters as well as the latest development of photocatalyst incorporated membrane.
Introduction: Dengue fever currently remains as one of the major public health issues in Malaysia. Dengue inci-dence in Malaysia has been increasing in the last 20 years. Dengue fever has been causing an economic burden to the country each year. Vector control is one of the preventions and control activities to reduce its incidence. Vector control activities, especially fogging is a resource-intensive activity. It uses most of the allocated budget of a district health office (33%). The major cost components of the prevention and control activities were human resources and pesticides with 60.7% were for human resources and 13.6% of the costs were for pesticides. Therefore, it is important to know, cost of each fogging activity and the factors that contribute to that cost. The objective of this study was to determine the costs of fogging activities carried out by Hulu Langat Health District Office, Selangor, Malaysia. Meth-ods: This study was a retrospective descriptive and analytical study using data from the Hulu Langat District Health Office for the year 2018. Cost analysis of fogging activities was carried out using the activity-based costing method-ology. The factors associated with, and predictors of, the costs of fogging activities were determined using chi-square and multiple linear regression. Results: In 2018, Hulu Langat District Health Office carried out total of 2,063 fogging activities. The average cost of each fogging activity was estimated as RM 1,579. Types of insecticides was statistically significant associated and predictive factor of the cost of fogging activity. Conclusion: The present study showed that the estimated average cost per fogging activity is RM 1,579 and water-based insecticide was found to be the cheaper option compared to oil-based insecticide. However, as this study did not determine the effectiveness of these insec-ticides, recommendations cannot be made as to which insecticide should be used.
Superhydrophilic graphene oxide/electrospun cellulose nanofibre (GO/CNF) was synthesized, characterized and successfully used in a solid-phase membrane tip adsorption (SPMTA) as an adsorbent towards a simultaneous analysis of polar organophosphorus pesticides (OPPs) in several food and water samples. Separation, determination and quantification were achieved prior to ultra-performance liquid chromatography coupled with ultraviolet detector. The influence of several parameters such as sample pH, adsorption time, adsorbent dosage and initial concentration were investigated. SPMTA was linear in the range of 0.05 and 10 mg l-1 under the optimum adsorption conditions (sample pH 12; 5 mg of adsorbent dosage; 15 min of adsorption time) for methyl parathion, ethoprophos, sulfotepp and chlorpyrifos with excellent correlation coefficients of 0.994-0.999. Acceptable precision (RSDs) as achieved for intraday (0.06-5.44%, n = 3) and interday (0.17-7.76%, n = 3) analyses. Low limits of detection (0.01-0.05 mg l-1) and satisfactory consistency in adsorption (71.14-99.95%) were obtained for the spiked OPPs from Sungai Pahang, Tasik Cheras, cabbages and rice samples. The adsorption data were well followed the second-order kinetic model and fits the Freundlich adsorption model. The newly synthesized GO/CNF showed a great adsorbent potential for OPPs analysis.
Extensive use of carbofuran insecticide harms the environment and human health. Carbofuran is an endocrine disruptor and has the highest acute toxicity to humans than all groups of carbamate pesticides used. Carbofuran is highly mobile in soil and soluble in water with a lengthy half-life (50 days). Therefore, it has the potential to contaminate groundwater and nearby water bodies after rainfall events. A bacterial strain BRC05 was isolated from agricultural soil characterized and presumptively identified as Enterobacter sp. The strain was immobilized using gellan gum as an entrapment material. The effect of different heavy metals and the ability of the immobilized cells to degrade carbofuran were compared with their free cell counterparts. The results showed a significant increase in the degradation of carbofuran by immobilized cells compared with freely suspended cells. Carbofuran was completely degraded within 9 h by immobilized cells at 50 mg/L, while it took 12 h for free cells to degrade carbofuran at the same concentration. Besides, the immobilized cells completely degraded carbofuran within 38 h at 100 mg/L. On the other hand, free cells degraded the compound in 68 h. The viability of the freely suspended cell and degradation efficiency was inhibited at a concentration greater than 100 mg/L. Whereas, the immobilized cells almost completely degraded carbofuran at 100 mg/L. At 250 mg/L concentration, the rate of degradation decreased significantly in free cells. The immobilized cells could also be reused for about nine cycles without losing their degradation activity. Hence, the gellan gum-immobilized cells of Enterobacter sp. could be potentially used in the bioremediation of carbofuran in contaminated soil.
Introduction: Chemical pesticide is commonly used among vegetable family farmers in Sabah. There is no system to monitor adverse health effects. This study is to determine the blood cholinesterase activity and associated factors among vegetable family farmers. Methods: A cross sectional study has involved 163 farmers aged 18-60 years old. Validated questionnaire was used to assess the associated factors. Lovibond AF267 Cholinesterase Kit was used to determine the blood cholinesterase activity. Chi square test was used to determine the association between blood cholinesterase activity and socio demographic factors and work practices. Results: Approximately 23.3% of study sample had low blood cholinesterase activity. There were significant associations between low blood cholinesterase activity with older age group (p
Cashew nut trees are consistently ant-visited throughout the year, with the ants attracted to a large number of extrafloral nectaries on the leaves, inflorescences, flowers, and developing nuts. The commercial production of cashew nut, for example, in India, Brazil, and east Africa, consistently applies pesticides, especially insecticides, in large monoculture plantings. Each year prophylactic spraying begins with the first flush of new leaves, continues through flowering, ending at about mid-nut development. We surveyed for ant diversity in sprayed and unsprayed cashew monocultures of various sizes and ages in Sri Lanka, India, and Malaysia to document the ant-cashew relationship and to explore the potential of ants replacing chemical pesticides in insect control. Using for-profit, commercial-size plantations as examples, we present information that cashew has a strong potential for arthropod-dependent protection from pests and suggest important habitat considerations for encouraging ants within cashew plantings.
The slow adoption of integrated pest management (IPM) has been attributed to the widespread gaps in farmers' knowledge of rational pest management. Other factors such as farmers' perception of high input use and promotion of pesticides also influence decisions to practise rational pest management. To bridge these gaps and improve farmers' pest management practices, most IPM implementation programmes rely on communication strategies. These communication approaches utilize either mass media or interpersonal channels or a combination. The choice of which communication approach to employ depends on project objectives and resources. Among extension and communication approaches used in crop protection, strategic extension campaigns, farmer field schools and farmer participatory research stand out in their ability to bring about significant changes in farmers' pest management practices. While extension campaigns have greater reach, farmer participation and experiential learning achieve more impact because learning effects are sustained. Communication media are important in raising awareness and creating a demand for IPM information but interpersonal channels and group methods such as the farmer field school and farmer participatory research are essential to accomplish the tasks of discovery and experiential learning of IPM skills.
The use of organochlorine pesticides has caused concern due to their effects on human health and the Malaysian aquatic ecosystem, particularly so in view of their persistent and bioaccumulative properties. Since the extent of organochlorine pesticide pollution in Malaysian waterways is unknown except for isolated instances, a systematic survey has now been carried out. Water samples from various rivers were extracted, cleaned up with Florisil and analysed for the individual organochlorine pesticides by gas chromatography (GC) with an electron capture detector (ECD). DDE, DDT and heptachlor were present in all the river water samples of the west coast of Peninsular Malaysia. Other organochlorine pesticides were also identified from the water samples. However, the levels of all these are still below criteria values for Malaysian aquatic life, indicating that organochlorine pesticide pollution is less of a problem than other organic or inorganic pollutants.
This study investigates pest management practices among lowland farmers on growing
leafy and fruit vegetables, particularly focusing on the pesticide usage in controlling pest. In
Malaysia, vegetable productions in lowland areas are to some extent really important as in the
highland areas due to the wide marketing channel, from local till traded across border. Yet, the
ignorance of vegetables safety regarding the appropriate of pesticide usage by farmers was
undeniable, as the market demands only products with good extrinsic quality. Thus a survey
was conducted among of 85 of lowland vegetable farmers to get information on their pest
management practices in farms. Result showed that the pesticide application by farmers on
vegetables crops still indicated a calendar spraying practices. In most cases, farmers tend to
harvest the vegetable products shortly after a few days of last pesticide spraying. In order to
enhance the food safety control starting from the primary production, extensive monitoring of
the current pesticide usage by farmers in vegetable productions is vital to provide an updated
data on the food safety risk regarding to the pesticide residues. Therefore, the thrust of this
paper was to get a better understanding on the level of safe pesticide usage among vegetables
farmers especially in areas of growing vegetables productions.
Microalgae are important biological resources that have a wide range of biotechnological
applications. Due to their high nutritional value, microalgae such as Spirulina and Chlorella are being mass cultured for health food. A variety of high-value products including polyunsaturated fatty acids (PUFA), pigments such as carotenoids and phycobiliproteins, and bioactive compounds are useful as nutraceuticals and pharmaceuticals, as well as for industrial applications. In terms of environmental biotechnology, microalgae are useful for bioremediation of agro-industrial wastewater, and as a biological tool for assessment and monitoring of environmental toxicants such as heavy metals, pesticides and pharmaceuticals. In recent years, microalgae have attracted much interest due to their potential use as feedstock for biodiesel production. In Malaysia, there has been active research on microalgal biotechnology for the past 30 years, tapping into the potential of our
rich microalgal resources for high-value products and applications in wastewater treatment and assessment of environmental toxicants. A culture collection of microalgae has been established, and this serves as an important resource for microalgal biotechnology
research. Microalgal biotechnology should continue to be regarded as a priority area of research in this country.
Orogastric lavage has been performed since 200 years ago for intoxicated patients. Due to the risk that outweighs benefits it has fallen out of favour for the last decade. A teenage girl presented to Emergency Department with history of ingestion of a bottle of pesticide within the time frame before gastric emptying. The girl was resuscitated, intubated and orogastric lavage was performed. Fifty cc of the toxic substance was siphoned and antidote of the toxin was administered. She was admitted to the Intensive Care Unit, subsequently recovered and discharge five days later. Definitive airway management, proper technique, correct selection of patients and adequate monitoring are paramount to the success of orogastric lavage.
Introduction: Pesticides may influence the physicochemical properties of soil and the water quality parameters, which is vital in maintaining soil fertility and producing high quality crops. Objective: This study aims to determine the relationship between the concentration of pesticides, the physicochemical properties of the paddy soil samples and the water quality parameters of paddy water samples. Methods: A total of 72 soil and 72 water samples were collected in Tanjung Karang, Malaysia. The paddy soil and water were extracted using Quick, Easy, Cheap, Efficient, Rugged and Safe (QuEChERS) and solid phase extraction (SPE) techniques respectively. The concentrations of pesti- cides were analysed in ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The relationship of the concentration of target pesticides and the paddy soil and water physicochemical properties were studied using Spearman correlation. Results: In paddy soil, the concentration of propiconazole shows moderate positive correlation with manganese (Mn) (r = 0.587) (p 0.01). Meanwhile buprofezin-total organic carbon (TOC) (r = -0.55) (p 0.01), imidacloprid-cation exchange capacity (CEC) (r = -0.519) (p 0.01), pymetrozine-sodium (Na) (r = -0.588) (p 0.01), and trifloxystrobin-calcium (Ca) (r = 0.566) (p 0.01) showed moderate negative correlation. Whereas in water, trifloxystrobin showed significant positive correlation with turbidity (r = 0.718) (p 0.01) and te- buconazole showed negative correlation to dissolved oxygen (DO) (r = 0.634) (p 0.01). Conclusion: The presence of pesticides in paddy field may influence the soil and water quality, thus regular monitoring of pesticides usage and nutrient management in soil is deemed important.
A study to assess the level of organochlorine pesticides (OCPs) and bisphenol A (BPA) in edible marine biota collected from coastal waters of Malaysia was conducted using GC-MS and SPE extraction. An analytical method was developed and validated to measure the level of 15 OCPs and BPA simultaneously from five selected marine species. It was observed that some samples had low levels of p,p'-DDE, p,p'-DDT and p,p'- DDD ranging from 0.50 ng g(-1) to 22.49 ng g(-1) dry weight (d.w) but significantly elevated level of endosulfan I was detected in a stingray sample at 2880 ng g(-1) d.w. BPA was detected in 31 out of 57 samples with concentration ranging from below quantification level (LOQ: 3 ng g(-1)) to 729 ng g(-1) d.w. The presence of OCPs is most likely from past use although there is also indication of illegal use in recent times. The study also reveals that BPA is more widely distributed in coastal species caught off the coast of the most developed state. The potential health risk from dietary intakes of OCPs and BPA from the analysed fish species was negligible.
A total of seven pesticides and eight alkylphenols were monitored using this method for the determination of their trace levels in human cord blood. The pesticides are lindane, diazinon, alpha-endosulfan, beta-endosulfan, endosulfan sulfate, chlorpyrifos and endrin; while the alkylphenols are 4-n-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol, 4-t-octylphenol, 4-n-heptylphenol, nonylphenol, 4-n-octylphenol and bisphenol A. The pesticides and alkylphenols in the cord blood samples were extracted with solid phase extraction IST C18 cartridges and analyzed by selected ion monitoring mode using quadrapole detector in Shimadzu QP-5000 gas chromatograph-mass spectrometer. Trace levels of pesticide and alkylphenols in the range of non-detectable to 15.17 ng ml(-1), were detected in the human cord blood samples. This technique of monitoring the levels of endocrine-disruptors in blood samples is consistent, reliable and cost effective while reducing wastage of time and solvents.
Members of the catadromous eel live in various fresh, brackish and marine habitats. Therefore, these eels can accumulate organic pollutants and are a suitable bioindicator species for determining the levels of organic contaminants within different water bodies. The ecological risk for organochlorine compounds (OCs) in Anguilla japonica with various migration patterns, such as freshwater, estuarine and marine residences, was examined to understand the specific accumulation patterns. The concentrations of HCB, ∑HCHs, ∑CHLs and ∑DDTs in the silver stage (maturing) eel were significantly higher than those in the yellow stage (immature) eel, in accordance with the higher lipid contents in the former versus the latter. The OC accumulations were clearly different among migratory types in the eel. The ecological risk of OCs increased as the freshwater residence period in the eel lengthened. The migratory histories and the lipid contents directly affected the OC accumulation in the catadromous eel species.