Analysis of Pesticides Using a Polyppyrole Modified Electrode

Electrochemical methods can provide fast, sensitive and sometimes real time detection of pesticides. In the course of this work, a dispersed mercury electrode has been used to detect pesticides electrochemically. The electrode was prepared by depositing a thin mercury film on a glassy carbon disc and then coating a layer of polypyrrole on the disc. The effect of coating thickness on detection sensitivity was studied. A thin mercury film of 0.34 µm dispersed by one cycle polymerization of pyrrole was preferred. The influence of electrolyte, pH and organic solvent content on pesticide response was also investigated. The polypyrrole dispersed mercury electrode (Hg-PPy/GC) was not suitable for a pH above 6 but it can tolerate acetonitrile up to 10% at which concentration the mercury film coated glassy carbon electrode (Hg/GC) failed to response. Methyl parathion, methyl azinphos, parathion and fenitrothion were detected. The sensitivity of the dispersed mercury electrode was similar to a normal thin mercury film electrode in this case. A good response can be obtained for 1 ppm pesticides using fast linear sweeping voltammetry.     

Detection of toxic heavy metals and pesticide residue in herbal plants which are commonly used in the herbal formulations

Herbal formulations are getting popular throughout the world and commercialized extensively for various medicinal properties. WHO has emphasized the need for quality assurance of herbal products, including testing of heavy metals and pesticides residues. In view of WHO guidelines, single herbal drugs used in herbal formulations were collected from local market, for testing heavy metals and persistent pesticides residue. Therefore, in the present case, we have examined few local samples of certain herbs viz. Emblica officinalis, Terminalia chebula, Terminalia belerica, and Withania somnifera. The present studies were selected for estimation of four heavy metals namely Arsenic, Cadmium, Lead, and Mercury. Apart from these, pesticide residue Viz. Organochlorine pesticides, Organophosphorus pesticides, and Pyrethroids were analyzed in the four samples of single crude drugs. Heavy metals and pesticide residue were found below detection limits in all the samples.     

The effect of mixtures of organophosphate and carbamate pesticides on acetylcholinesterase and application of chemometrics to identify pesticides in mixtures

Organophosphate (OP) and carbamate (CP) pesticides act by the inhibition of acetylcholinesterase (AChE). This enables the use of this enzyme for the detection of these pesticides in the environment. While many studies have looked at the effect of single pesticides on AChE, the effect of mixtures of pesticides still requires extensive investigation. This is important to evaluate the cumulative risk in the case of simultaneous exposure to multiple pesticides. Therefore we examined the effect of five different pesticides (carbaryl, carbofuran, parathion, demeton-S-methyl, and aldicarb) on AChE activity to determine whether combinations had an additive, synergistic, or antagonistic inhibitory effect. Results indicated that the mixtures had an additive inhibitory effect on AChE activity. The data from the assays of the mixtures were used to develop and train an artificial neural network (ANN) which was then utilised successfully for the identification of pesticides and their concentrations in mixtures. This study is significant because it evaluated mixtures of OPs and CPs where previous studies focused on either OPs or CPs. Previous studies have only examined up to three pesticides while this study evaluated mixtures of five pesticides simultaneously. This is also the first study where an ANN was able to utilise data from the inhibition of a single enzyme to differentiate five different pesticides and their concentrations from mixtures.     

Rapid analysis of neonicotinoid insecticides in guttation drops of corn seedlings obtained from coated seeds

Regarding the hypothesis that neonicotinoid insecticides used for seed coating of agricultural crops - mainly corn, sunflower and seed rape - are related to the extensive death of honey bees, the phenomenon of corn seedling guttation has been recently considered as a possible route of exposure of bees to these systemic insecticides. In the present study, guttation drops of corn plants obtained from commercial seeds coated with thiamethoxam, clothianidin, imidacloprid and fipronil have been analyzed by an optimized fast UHPLC-DAD procedure showing excellent detection limits and accuracy, both adequate for the purpose. The young plants grown both in pots - in greenhouse - and in open field from coated seeds, produced guttation solutions containing high levels of the neonicotinoid insecticides (up to 346 mg L(-1) for imidacloprid, 102 mg L(-1) for clothianidin and 146 mg L(-1) for thiamethoxam). These concentration levels may represent lethal doses for bees that use guttation drops as a source of water. The neonicotinoid concentrations in guttation drops progressively decrease during the first 10-15 days after the emergence of the plant from the soil. Otherwise fipronil, which is a non-systemic phenylpyrazole insecticide, was never detected into guttation drops. Current results confirm that the physiological fluids of the corn plant can effectively transfer neonicotinoid insecticides from the seed onto the surface of the leaves, where guttation drops may expose bees and other insects to elevated doses of neurotoxic insecticides.     

Amperometric Detection of Pesticides Using Polymer Electrodes

Abstact The real time monitoring of some organophosphorus based pesticides is of great concern to environmentalists because the widespread use of pesticides is causing severe health hazards to all living beings and also hampering our ecological balance. The traditional methods of measurement of pesticide residues are time consuming, need sample pre-treatment, and lack desired specificity and accuracy. We have developed an amperometric biosensor for indirect measurement of the pesticide concentration precisely in ppb level. The method is based on the action of two enzymes namely acetylcholine esterase and choline oxidase which are uniquely immobilized in a polymeric porous network directly on the working electrode of a screen-printed sensor. Polyacrylamide matrix has been prepared by copolymerisation of acrylamide andN,N′-methylenebisacrylamide using Potassium peroxodisulphate (K₂S₂O₈) as initiator. A linear relationship was obtained between the range of 0 to 10 ppb.     

Evaluation of river pollution of neonicotinoids in Osaka City (Japan) by LC/MS with dopant-assisted photoionisation

An atmospheric pressure photoionisation (APPI) source for liquid chromatography/mass spectrometry (LC/MS) was applied to determine neonicotinoid pesticides in the aquatic environment. Dopant-assisted APPI was very effective in the ionisation of neonicotinoids. Neonicotinoids generated protonated molecules in APPI with high sensitivity, while adduct ions, such as sodiated molecules, were predominantly generated in conventional electrospray ionisation. The ionisation of neonicotinoids was confirmed by ultra-high-resolution MS. An analytical method coupled with solid phase extraction was developed for acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, and thiamethoxam. Method detection limits were 0.47 to 2.1 ng L(-1) for six neonicotinoids. Dinotefuran was the most frequent and highest among the neonicotinoids examined in the aquatic environment in Osaka, Japan. The maximum concentration of dinotefuran was 220 ng L(-1). Given the toxicity of neonicotinoids for aquatic creatures, the concentrations observed here were substantially low. The change in concentrations was temporally coincident with the period of the neonicotinoid application. Although rapid photodegradation and some degradation products have been elucidated, the degradation products in the aquatic environment were not identified in the present study.     

Multiresidue analysis of neonicotinoids by solid-phase extraction technique using high-performance liquid chromatography

For routine monitoring of pesticides, a multiresidue analysis through solid-phase extraction technique and using high-performance liquid chromatography (HPLC) in cotton seed cake (CSC) has been developed. Extraction of fortified samples was carried out with aqueous acetone under vacuum. The concentrated extract was loaded onto the solid-phase extraction units, preconditioned with acetonitrile. The extraction units were then washed with hexane and finally eluted with acetonitrile. The pesticide residues were determined using a multiresidue method by reversed-phase HPLC. The average percentage recoveries were found to range between 65.47% and 110% at spiking levels of 10 to 40 mg/kg. The method developed shows a healthy rate of recovery and can successfully be utilized for the extraction and screening of neonicotinoid residues in CSC. The detection limits for imidacloprid, acetamiprid, and thiacloprid using this method were found to be 5, 10, and 20 mg/kg, respectively.     

Impacts of pesticides in a Central California estuary

Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured in the estuary. This study suggests that the same pyrethroid and organophosphate pesticides that have been shown to cause water and sediment toxicity in urban and agriculture water bodies throughout California, have the potential to affect estuarine habitats. The results establish baseline data in the Santa Maria River estuary to allow evaluation of ecosystem improvement as management initiatives to reduce pesticide runoff are implemented in this watershed.     

Analysis of pesticide residues in Peninsular Malaysian waterways

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.     

A novel environmental indicator for monitoring of pesticides

The identification of an indicator for monitoring pesticides is a very effective analytical approach because it allows one to schedule and simplify the analytical routine. In this study, a new indicator has been designed, which has to be able to define a scale of priorities in the pesticides monitoring. A starting equation was developed involving the escaping tendency of a given substance from a phase (based on the Mackay model I level). The reliability of the indicator was tested by application to a model system, consisting of a defined and limited area, choosing water as matrix over a period of 6 years. A group of marker compounds was also defined to implement the predictive efficacy of the indicator. The results obtained by modeling were compared to those obtained by experimentation of the same model system. The indicator was subsequently and appropriately modified creating a new equation, including a kinetic factor, which considers the environmental degradation processes. The effect of the rectified indicator was consistent with the sales data list of compounds, when applied to the markers. The indicator developed in this study, tested as a model on specific area-phase-period (Province of Siena, water phase, 2000?C2006), is applicable to any other area-phase-period, adjusting the partition value of the Mackay model for the case under study.     

Pesticide occurrence and aquatic benchmark exceedances in urban surface waters and sediments in three urban areas of California, USA, 2008–2011

Urban pesticide use has a direct impact on surface water quality. To determine the extent of pesticide contamination, the California Department of Pesticide Regulation initiated a multi-area urban monitoring program in 2008. Water and sediment samples were collected at sites unaffected by agricultural inputs in three areas: Sacramento (SAC), San Francisco Bay (SFB), and Orange County (OC). Samples were analyzed for up to 64 pesticides or degradates. Multiple detections were common; 50 % of the water samples contained five or more pesticides. Statewide, the most frequently detected insecticides in water were bifenthrin, imidacloprid, fipronil, fipronil sulfone, fipronil desulfinyl, carbaryl, and malathion. Bifenthrin was the most common contaminant in sediment samples. Key differences by area: OC had more pesticides detected than SAC or SFB with higher concentrations of fipronil, whereas SAC had higher concentrations of bifenthrin. The most frequently detected herbicides were 2,4-D, triclopyr, dicamba, diuron, and pendimethalin. Key differences by area: OC and SFB had higher concentrations of triclopyr, whereas SAC had higher concentrations of 2,4-D and dicamba. Detection frequency, number of pesticides per sample, and pesticide concentration increased during rainstorm events. In water samples, all of the bifenthrin, malathion, fipronil, permethrin, and λ-cyhalothrin detections, and most of the fipronil sulfone and cyfluthrin detections were above their lowest US EPA aquatic benchmark. Diuron was the only herbicide that was detected above its lowest benchmark. Based on the number of pesticides and exceedances of aquatic benchmarks or the high number of sediment toxicity units, pesticides are abundant in California surface waters.     

Pesticide concentrations in air and precipitation in the Netherlands

Atmospheric deposition may be an important source of persistent organic compounds (POP) and pesticides for the Dutch coastal and inland waters. Current estimates of the atmospheric input have been made using atmospheric dispersion models. The uncertainty is however large. A project was defined with the aim to assess the input on the basis of measurements. For a period of two years (1999-2001) a monitoring network was operated. At eighteen stations, located across the whole country, air and precipitation samples were taken on a weekly and monthly basis. In these samples the concentrations of pesticides, PCB's and PAH's were determined. Up to 50 different pesticides were observed in precipitation and air. The concentration of 17 of these in precipitation exceeded the maximum permissible level for surface water and 22 exceeded the standard for drinking water of 100 ng l(-1). The input from the atmosphere to Dutch inland waters appeared to be as large as the input of pesticides by other sources such as spray drift. Model calculations were also carried out to identify the sources of these compounds. The occurrence of atrazine could be related to emissions outside the Netherlands.     

Evaluation of soil contamination in intensive agricultural areas by pesticides and organic pollutants: south-eastern Spain as a case study

A comprehensive survey of the occurrence and fate of pesticides and organic contaminants in soils from an intensive agricultural area devoted to horticultural production in plastic-based greenhouses has been performed to determine if the operation under integrated pest management practices has contributed to reduce the levels of these compounds. Almería province (south-eastern Spain) was selected for the case study. 38 agricultural soil samples (each sample corresponds to an independent private greenhouse) of areas working under integrated pest management (IPM) programs have been analyzed in order to evaluate their contamination fate. Sampling was designed to cover an area of about 400 km(2). Pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phenolic compounds and di-(2-ethylhexyl)phthalate (DEHP) were monitored. The obtained results were compared to other studies reported in Spain and Europe. Among relevant persistent pesticides, DDTs and endosulfans were mainly found and the results indicated historical application, although recent application of endosulfan was rarely detected. PAHs were also found but to a lesser extent and derived from pyrogenic sources. DEHP levels were considerably higher in comparison to the other monitored analytes. The evaluation revealed that despite the use of IPM programs, pesticide and organic contaminants are still being detected in this type of agricultural soil, although at relatively low concentration levels. In general, the contamination rate was similar or lower in comparison to other agricultural areas from nearby regions or countries. However, further monitoring studies should be carried out to establish the possible reduction in contamination by the selected compounds.     

Field comparison of manual and semi-automatic methods for the measurement of total gaseous mercury in ambient air and assessment of equivalence

The manual and semi-automatic methods for the measurement of total gaseous mercury in ambient air have been compared in a field trial for the first time. The comparison results have shown that whilst the expected random scatter is present, there was no significant systematic bias between the two methods, whose operational differences have also been outlined and analysed in this work. Furthermore it has been observed that because variation in instrument sensitivity is largely random in nature there is little effect on the results of the comparison if the period between instrument calibrations is altered. When the manual and semi-automatic methods are compared according to guidelines produced by the European Commission the results presented here, taken together with other supporting evidence, strongly suggest that the two methods are equivalent.     

Effects of anticholinesterase drugs on biomarkers and behavior of pumpkinseed, Lepomis gibbosus (Linnaeus, 1758)

The presence of pharmaceutical residues in the aquatic environment has recently received great attention, as potential adverse effects may arise from their presence. Inhibition of cholinesterases (ChE) has been widely used as an environmental biomarker of exposure to organophosphates (OP) and carbamate (CB) pesticides. However, other widespread anthropogenic contaminants - including pharmaceutical drugs - can exert toxic effects through ChE inhibition. Studies with aquatic species have shown that inhibition of ChE is associated with behavioral changes. Bearing this in mind, this work aimed to study the effects on individual behavior and acetylcholinesterase (AChE) activity of selected tissues of Lepomis gibbosus, after exposure to the anticholinesterasic drugs neostigmine and pyridostigmine. Results revealed that neostigmine significantly decreased the activity of AChE in the head (LOEC = 100 mg L(-1)), but not in dorsal muscle. On the other hand, pyridostigmine significantly decreased the activity of AChE in both the head (LOEC = 0.001 mg L(-1)) and dorsal muscle homogenates (LOEC = 100 mg L(-1)). The impairment of this enzymatic form was attained at ecologically relevant concentrations (in the case of pyridostigmine, for head AChE), which is an interesting finding, specially considering that these toxic effects occurred for a pharmaceutical compound. Contrarily, there were no significant differences in the behavior of L. gibbosus in any parameter, for neither drug. These results suggest that the behavioral parameters analyzed (scototaxis and lethargy) in L. gibbosus could not be regarded as suitable markers to assess the effects of drugs such as neostigmine and pyridostigmine. In contrast, the pattern of response elicited by cholinesterasic inhibition showed the usefulness of this toxicological parameter for the assessment of pharmaceuticals in the environment, namely anticholinesterasics.     

Advanced energy consumption system for smart farm based on reactive energy utilization technologies

Over the decades, both agriculture and energy grids have encountered significant challenges, such as the lack of power supply to agricultural farms and the difficulties of renewable energy use in the electricity sector. To overcome and address these issues, this paper presents an idea of merging smart farm and renewable energy, using surplus renewable energy for the agriculture sector using the smart farm for renewable energy supplies. First, demonstrate the framework to connect a smart farm energy system and analyze its feasibility and advantages. In this paper, Reactive Energy Utilization Technology (REUT) has been used as an efficient energy consumption system for the smart farm. It is used to predict the optimum wind power scenario in the smart farm by monitoring continuous control variables, with the lowest voltage reached in each scenario, and minimized actual total power losses. A combined system consisting of smart farming production, as well as renewable energy consumption, has been evaluated in experimental results. Experimental results and discussion shows that the proposed method has better renewable energy consumption, accuracy(96.7%), and efficiency(95.6%) for smart farming.     

Review of PSR framework and development of a DPSIR model to assess greenhouse effect in Taiwan

In dealing with the complex issues of greenhouse gas (GHG) emission and climate change mitigation, many interrelated factors such as cost, level of technology development, supply and demand of energy, structure of industry, and expenditures on research and development exist. Using indicators to monitor environmental impacts and evaluate the efficacies of policies and regulations has been practiced for a long time, and it can serve as a useful tool for decision making and for comparison between different countries. Although numerous indicators have been developed for relevant subjects, integrated approaches that consider individual changes, dynamic interaction, and multi-dimensions of indicators are scarce. This paper aimed to develop a Driving Force-Pressure-State-Impact-Response (DPSIR) framework to assess the problems. This DPSIR model is mainly related to energy consumption, environmental impacts, and policy responses. The objectives of the paper were: (1) conduct a literature review on the indicators that have been used in GHG-related studies; (2) develop a DPSIR model that incorporates GHG-related indicators and evaluate their relationships using a cause?Ceffect chain of GHG emission; and (3) develop a calculative method that can be used to explain the dynamic correlation among the interdependent indicators. Taiwan is a significant source of global GHG emissions. A case study, using the developed framework and Taiwan??s actual data of the past two decades, was conducted. The results indicate that regulatory strategies for pollution control are inadequate in terms of ensuring environmental quality, and the nature does not have the capability to revert the impacts from the existing level of pollution.     

基于卫星遥感的生态保护红线人类活动提取方法研究

目前全国生态保护红线划定工作基本结束,开展生态保护红线监管工作事关国家生态安全,是今后我国生态保护的重要举措和重点工作。依托国家生态保护红线监管平台监管业务系统,研究基于卫星遥感的生态保护红线人类活动提取方法和流程,并以宁夏为例,验证其科学性和可靠性。结果显示:基于卫星遥感技术构建的方法精度较高,可操作性较强,为生态保护红线人类活动监管提供了思路;使用该技术方法的作业效率相比人工解译提升了2~3倍,提取的宁夏生态破坏问题图斑准确率达到66%,人类活动提取准确率更是达到95%,能够满足生态保护红线人类活动监管需求;宁夏55%的县(区、市)生态保护红线内发现新增和规模扩大人类活动,从空间分布来看,主要集中在西部和南部,北部和中部分布较少,其中彭阳县、沙坡头区和中宁县人类活动影响面积最大。     

Trends of organochlorine pesticides in drinking water supplies

The effectiveness of the treatment process for the removal of pesticides in the final water supplies in Delhi has been evaluated. Samples were collected during 2000–2005 from five water treatment plants (WTPs). Analysis was carried out to identify pesticides, which are more commonly encountered in treated drinking water. In most of the treatment plants, the concentrations of lindane, total endosulphan and total DDT were significantly less in the finished water. Monitoring of these less soluble pesticide in the finished water from WTPs was done quarterly to arrive at the quality trends and to plan for the mitigation action, in case the concentration of the parameter exceeded at any site or time.