Fate and Transport of Pesticides

The chargeability of liquid sprays is an important factor in determining the deposition efficiency of electro-static pesticide sprays. The Rayleigh limit provides information on the maximum amount of charge a spray drop can carry as a function of droplet size. This paper reviews the literature to determine what fraction of the Ray-leigh limit is achievable. Typically less than 10% of the Rayleigh limit charge is obtained. The drop charge per unit mass decreases with increasing drop size and liquid flow rate. A correlation equation is derived from published data to predict spray drop charge from drop size and flow rate. Introduction The chargeability of liquid sprays is an important factor in determining the deposition efficiency of electro-static pesticide sprays. Law [1] recommends a charging level on the order of 1 mC/kg for electrostatic forces to be strong enough to overcome aerodynamic drag and gravity and alter the drops' trajectories to improve deposi-tion. Charging levels of around 10 mC/kg are the most that is typically seen in field equipment [1]. As with most theoretical limits, in practice charging levels rarely approach the Rayleigh limit. So what level of charging is realistically achievable with modern electrostatic pesticide spraying equipment? This paper reviews the literature to determine what fraction of the Rayleigh limit is achievable. To calculate this fraction requires published values for both spray cloud charge per unit mass and average drop size simultaneously in the same spray, which is rarely reported.

Sulfonylureas are a unique group of herbicides used for controlling a range of weeds and some grasses in a variety of crops and vegetables. They have been extremely popular worldwide because of their low mammalian toxicity, low use rate, and unprecedented herbicidal activity. Knowledge about the fate and behavior of sulfonylurea herbicides in the soil-water environment appears to be of utmost importance for agronomic systems and environmental protection. Because these herbicides are applied at a very low rate, and their mobility is greatly affected by the chemicals' anionic nature in alkaline soils, a thorough understanding of their degradation/hydrolysis processes and mechanisms under aqueous and soil systems is important. This review brings together published information on the hydrolysis of several sulfonylureas in aqueous and soil solutions that includes the effects of pH, temperature, functional relationship between pH vs hydrolysis rate constants, and hydrolysis behavior of sulfonylureas in the presence of minerals. In addition, the transformations of sulfonylureas in soil, under laboratory and field experiments, have been discussed in connection with the compounds' varied structural features, i.e., sulfonylueas that are with or without the pyridinic, pyrimidine, and triazinic ring.

Metalaxyl and chlorpyriphos are widely used pesticides around the world. The purpose of this study was to evaluate validation parameters, matrix effect (ME %), reduction behavior, processing factor (PF) and estimate the behavior of metalaxyl and chlorpyriphos in tomato fruit samples. ''Quick, Easy, Cheap, Effective, Rugged, and Safe'' (QuEChERS) extraction and gas chromatography coupled to mass spectrometry (GC/MS) were used for the analysis. Results showed successful trends by evaluating validation parameters [selectivity, linearity, limits of detection (LOD), limits of quan-tification (LOQ) and precision]. The correlation coefficients were[0.99; the LOD for metalaxyl ranged from 0.01 to 0.003 mg/kg and the LOQ for chlorpyriphos ranged from 0.03 to 0.009 mg/kg. The matrix effect (ME %) of metalaxyl was found to exhibit a medium matrix effect while for chlorpyriphos no matrix effect was seen. Recovery (70-120%) and precision (RSD \ 20%) for both pesticides metalaxyl and chlorpyriphos were within the satisfactory ranges recommended by the European Commission. The PF was generally \ 1 (ranged between 0.34 and 0.98). Except when using washing solutions, metalaxyl PFs were[ 1. The highest reduction rate was achieved by sonication treatments which could effectively remove chlorpyriphos residues spiked in tomato matrices rather than the metalaxyl residues. On the other hand, washing treatments were less efficient in removing metalaxyl residues from tomato samples. Overall, any one of these processes can contribute substantially to reduce consumer exposure to pesticides residues in tomatoes.

The present study deals with the investigation of existing pollution levels and potential ecological risk assessment of endocrine-disrupting organochlorine and organophosphorous pesticide residues in the Vasai Creek water near Mumbai. The average concentration of α-and β-endosulfan (137.75 ng·L −1) exceeds the chronic criteria level of α-and β-endosulfan (6.5 ng·L −1) set by US EPA for freshwater aquatic organisms. The concentration levels of aldrin (75.31 ng·L −1), dieldrin (71.19 ng·L −1) and endrin (76.60 ng·L −1) was found to exceed the respective criteria levels of b0.13, 65.1, and 61 ng·L −1 as set by US EPA for protection of freshwater aquatic organisms. In addition, the level of chlorpyrifos (208.77 ng·L −1) exceeds the recommended concentration value of b 35 ng·L −1 set by Ministry of Environment of British Colombia. The results of our study give an indication of probable ecotoxicological risk to the marine breeding organisms of creek.

Residues of some rational insecticides (etofenprox, imidacloprid and spirotetramat) in tomatoes fruits were determined after three applications. The results showed that the residues of tested insecticides in zero time (after one hour of insecticides treatment) were the maximum. After the first application the residues of these insecticides were 2.62, 0.91 and 0.95 mg/kg for imidacloprid, spirotetramat and etofenprox, respectively. The corresponding results after the second and third applications were 3.14, 0.95 and 0.96; 3.42, 1.06 and 0.86 mg/kg, respectively. After one week intervals the insecticides residues were decreased to 0.089, 0 and 0; 0.009, 0 and 0; 0.18, 0.04 and 0.05 mg/kg, respectively. The dissipation rate after the third application was 94.7, 92.2 and 94.2% for imidacloprid, spirotetramat and etofenprox, respectively. The results showed that imidacloprid has a minimum preharvest interval (PHI) followed by spirotetramat and etofenprox. The Pre-Harvest Interval (PHI) was 3.8, 5.8 and 6.8 days, respectively. The results showed also, imidacloprid was the most toxic against sweet potato whitefly adults followed by etofenprox and spirotetramat. The reduction percent of whitefly adults was 98.7, 93.7 and 30%, respectively. The results recommended that using of imidacloprid in sweet potato whitefly control was effective and safely.

The degradation and leaching of napropamide were compared between Beach Ridges Interspersed with Swales (BRIS) soil samples, and the same soil samples amended with 20 mg ha À1 of either chicken dung (CD) or palm oil mill effluent (POME). The effects of removing dissolved organic carbon (DOC) from the soil samples on napropamide degradation and leaching were also studied. The addition of CD and POME to BRIS soil increased the napropamide half-life values to 69 and 49.5 days, respectively. Sterilization of the soil samples resulted in partial inhibition of napropamide degradation in all soil samples. The half-lives of napropamide in BRIS soils receiving 0, 20, 100, and 200 mg kg À1 of DOC derived from CD were 43, 46.2, 53.4, and 63 days, respectively. The napropamide half-lives in soil samples treated with 0, 20, 100, and 200 mg kg À1 of DOC derived from POME were 43, 49.2, 57.7, and 69 days, respectively. However, in the sterilized soil samples, there were no significant effects of adding DOC derived from either CD or POME on napropamide half-lives. Incorporating either CD or POME decreased napropamide leaching and total amounts of napropamide remained in the soil columns after two pore volumes of water has been leached were higher in the amended than the non-amended soil. The CD was more effective in decreasing napropamide leaching than the POME. There were no effects of DOC on napropamide leaching in all soil treatments.

Introduction: The occupational toxic risks from agricultural activities in El Salvador affect human and environmental health. The objective of this paper is to describe the management of pesticide by farmers confirmed with a chronic kidney disease of uncertain etiology (CKDu) not associated to diabetes mellitus or hypertension. Methods: The study involved 42 male patients older than 18 years old with confirmed CKDu that have participated in different stages of pesticides management. This is a cross-sectional study; it was conducted from January to June 2011, in three communities of Bajo Lempa region, El Salvador. An interview was especially designed to investigate which pesticides were used and the farmer practices at different stages of pesticide use. Statistical descriptive analysis was carried out for the several studied variables. Results: All interviewed people had a direct relationship with agricultural activities. The majority of patients had poor education, 19% were illiterate and 55% only have primary education. Most farmers with CKDu had been exposed more than 10 years to hazardous pesticides. The most used pesticide was Hedonal/2, 4 D (100%). 95% interviewed patients mixed different pesticides and 63% dumped empty pesticide containers in the fields. Interviewees did not use appropriate personal protective equipment (100%). Conclusions: There is high use of hazardous pesticides by patients and some of these are banned and some are legal in El Salvador, but prohibited by other countries. Interviewed CKDu patients had high exposure to toxic pesticides due to the misuse in almost all stages. There is inadequate legislation and a poor law enforcement to prevent the misuse of pesticides in El Salvador. R. Mejía et al.

All groups of pesticides are toxic substances added deliberately to the micro and macro environment for their toxicity and biocidal effects to kill and harm living things. They do get added as their fall out to the environment. This unintentional act has had all the damaging effects not only on the microenvironment where they are used but also the macro and the global environment since their use has become immensely widespread, and they and their degraded or biotransformed products can be carried by air and water to far off distances. They can now be found anywhere on earth, contaminating soil, air, groundwater, surface water, rain, snow, and fog. Even the Arctic ice pack and the deep beds of the ocean are not spared from their presence. They and their residues, which are often more toxic than the parent compounds, have found their pathway into the food chain and have poisoned the birds, fish, wildlife, domestic animals, livestock, and human beings, including newborn babies.

The impact of toxicity of pesticides is heavy as well as pervasive owing mainly to a wide range of their application for crop protection and home use as may be estimated from the share of their different classes in the market viz. herbicides 51%, insecticides 25%, fungicides 20% and others 4%. Herbicides have a larger market in the industrialized countries for home use for maintaining the lawns and for managing golf courses, parks and recreation areas. The use of insecticides and fungicides is extensive in crop protection but their home use has grown substantially during the last two decades. Homeowners and urban dwellers are thus at great risk of exposure to the toxic trail of chemical pesticides.

The indiscriminate use of these chemicals on a massive scale such as that mentioned above has had profound impact on the living environment. According to a report by UNICEF, UNEP and WHO, the impact of the use of highly toxic chemicals takes the toll of about 5,500 children each day around the world from diseases caused by polluted air, water, food and environmental contaminants, which include the pesticides. Since the 1970s, the incidence of cancers, learning disabilities, autism, diabetes, early puberty, and abnormal penile development has skyrocketed among the children who comprise the most vulnerable group of citizens(ENS, May 10, 2002).

It has been pointed out earlier that synthetic chemical pesticides had not been adequately tested for their chronic toxicity and not evaluated at all for their developmental toxicity. The study of developmental toxicology did not make such enviable progress as development of chemicals and that created a complete lack of understanding on how life processes may be affected by potentially toxic chemicals such as the pesticides. Although hazards of chemical poisoning had taken toll of hundreds of lives in the past yet it was not until the mid-1960s that chronic toxicity of the pesticides became a matter of concern. In the mean time evidences continued to pile up on the linkage of many of the hitherto unknown disorders with exposure to chemical pesticides that are carcinogenic, mutagenic, teratogenic and hormone disrupting.

Damages done to the health of individuals by chemical pesticides have a wide range starting from acute toxicity with a single dose or exposure, to sub-chronic toxicity resulting from a few exposures and finally to chronic toxicity due to long term persistent exposures for each possible toxic end point. The toxic end points include cancer, damage to organs like the liver, kidney or heart, developmental disorders, damage to the immune system, central nervous system, reproductive system, and to the genes. Organisms, including test animals and man, react differently at different stages of development, particularly while in the womb, where scores of endpoints can be established, depending on the toxicity trail of the chemical pesticides and their end points. Such endpoints were either unknown for reasons of lack of understanding on developmental toxicology or were ignored when the pesticides and other toxic chemicals were introduced into the living systems.

Through the study of substituted anilines and benzylamines, we demonstrated that cooperative cation−π, π−π, and van der Waals interactions can increase aromatic cationic amine sorption to Na/Ca-montmorillonite well beyond the extent expected by cation exchange alone. Cationic amines exhibiting cooperative interactions displayed nonlinear Sshaped isotherms and increased affinity for the sorbent at low surface coverage; parallel cation exchange and cooperative interactions were noted above a sorption threshold of 0.3−2.3% of exchange sites occupied. Our experiments revealed the predominance of intermolecular cation−π interactions, which occurred between the π system of a compound retained on the surface via cation exchange and the cationic amine group of an adjacent molecule. Compounds with greater amine charge/area and electron-donating substituents that allowed for greater electron density at the center of the aromatic ring showed a greater potential for cation−π interactions on montmorillonite surfaces. However, benzylamine sorption to nine soils, at charge loadings comparable to the experiments with montmorillonite, revealed no significant cooperative interactions. It appears that cation−π interactions may be likely in soils with exceptionally high cation exchange capacities (>0.7 mol charge/kg) and low organic matter contents, abundant in montmorillonite and other expanding clay minerals.

This paper overviews the contamination caused by persistent organochlorines in endocrine system of mammals. To overcome yield loss in crops plants via pests, it is necessary to control them. There are a number of pest control strategies. But in developing and under developed countries, most of the farmers are using pesticides without a proper way and proper knowledge. Out of total applied pesticide, <0.1% of pesticides reach their target pests. Due to this reason, more than 99.9% of pesticides applied affect the public health, contaminate soil, water, and natural resources of our environment. The contamination by organochlorine residues is due to continuous usage in developing and under developed countries. In field and laboratory experiments, it was found that organochlorines are most persistent in nature which causes adverse effects on endocrine system in mammals. Endocrine disruption induces Alzheimer's disease, Parkinson's disease, Thyrotoxicosis, malformation of glands and reproductive organs, histological changes in organ system and homeostasis of mammals. Therefore low persistent insecticides and plant derivatives must be applied for pest control because they are safer to our biota and ecosystem.

Introduction: The occupational toxic risks from agricultural activities in El Salvador affect human and environmental health. The objective of this paper is to describe the management of pesticide by farmers confirmed with a chronic kidney disease of uncertain etiology (CKDu) not associated to diabetes mellitus or hypertension. Methods: The study involved 42 male patients older than 18 years old with confirmed CKDu that have participated in different stages of pesticides management. This is a cross-sectional study; it was conducted from January to June 2011, in three communities of Bajo Lempa region, El Salvador. An interview was especially designed to investigate which pesticides were used and the farmer practices at different stages of pesticide use. Statistical descriptive analysis was carried out for the several studied variables. Results: All interviewed people had a direct relationship with agricultural activities. The majority of patients had poor education, 19% were illitera...

Kiwifruit are sprayed in late winter with hydrogen cyanamide to enhance with bud burst. Te trellis layout of kiwifruit vines in combination with the canopy dormancy at that time of year means that a higher portion of the spray is able to drift away from the canopy. A spray application field study was conducted in a kiwifruit orchard to investigate spray drift potential, with particular focus for conditions relevant to hydrogen cyanamide applications. Spray application with conventional airblast-sprayer hollow-cone nozzles/ adjuvant was compared with air-induction (AI) nozzles/drift-reducing adjuvant. Spray was applied every second row in the orchard with spray drift sampling conducted by measuring vertical distribution of spray deposition on both sides of the downwind shelterbelt. The trial showed that airborne drift carried to a height of at least 15 m to the downwind edge of the orchard, which was the height of the vertical sampling towers. Te air-induction nozzle/driftreducing adjuvant system reduced the drift intercepted at 15 m height on the downwind side of the shelterbelt by approximately 78% compared to the standard nozzle/adjuvant system.

Electrostatic application of spray drops provides unique opportunities to precisely control the application of pesticides due to the additional electrostatic force on the spray drops, in addition to the normally seen forces of aerodynamic drag, gravity, and inertia. In this work, we develop a computational model to predict the spray drop trajectories. The model is validated through experiments with high speed photography of spray drop trajectories, and quantification of which trajectories lead to the "wrap-around effect", which results in drop deposition on the back side of the target leaf or fruit surface.

Repeated applications of glyphosate may contaminate the soil and water and threaten their quality both within the environmental system and beyond it through water erosion related processes and leaching. In this study, we focused on the transport of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) related to soil erosion at two slope gradients (10 and 20°), two rates of pesticide with a formulation of glyphosate (Roundup®) application (360 and 720 mg m −2 ), and a rain intensity of 1.0 mm min −1 for 1 h on bare soil in hydraulic flumes. Runoff and erosion rate were significantly different within slope gradients (p b 0.05) while suspended load concentration was relatively constant after 15 min of rainfall. The glyphosate and AMPA concentration in the runoff and suspended load gradually decreased. Significant power and exponent function relationship were observed between rainfall duration and the concentration of glyphosate and AMPA (p b 0.01) in runoff and suspended load, respectively. Meanwhile, glyphosate and AMPA content in the eroded material depended more on the initial rate of application than on the slope gradients. The transport rate of glyphosate by runoff and suspended load was approximately 14% of the applied amount, and the chemicals were mainly transported in the suspended load. The glyphosate and AMPA content in the flume soil at the end of the experiment decreased significantly with depth (p b 0.05), and approximately 72, 2, and 3% of the applied glyphosate (including AMPA) j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v remained in the 0-2, 2-5, and 5-10 cm soil layers, respectively. The risk of contamination in deep soil and the groundwater was thus low, but 5% of the initial application did reach the 2-10 cm soil layer. The risk of contamination of surface water through runoff and sedimentation, however, can be considerable, especially in regions where rain-induced soil erosion is common.

Statistical calibration of flow and transport models in unsaturated porous media is often carried out with Markov Chain Monte Carlo (MCMC) methods. However, the practicality of these methods is limited by their computational requirement, particularly when large prior intervals are assigned to the model parameters. In this work, a new operational strategy is investigated to alleviate the computational burden of MCMC samplers using results from a preliminary calibration performed with the First-Order Approximation (FOA) method. With the new strategy, the posterior distribution is approximated using a high-order Polynomial Chaos Expansion (PCE) surrogate model constructed over reduced parameter ranges. The latter are obtained from the 99.9 FOA confidence intervals. Two challenging test cases are investigated to assess efficiency and accuracy of the new strategy. The first test case considers estimation of flow and pesticide transport parameters from a synthetic infiltration experiment. The second test case deals with the assessment of unsaturated hydraulic soil parameters from a real-word laboratory drainage experiment. The results of the proposed strategy are compared to those of FOA, of the standard MCMC method and of an improved MCMC method in which the sampler is preconditioned with draws from the FOA posterior distribution. For both test cases, the new strategy provides accurate mean estimated parameter values and uncertainty regions and is much more efficient than the other MCMC methods. It is up to 50 times more efficient than the standard MCMC method.

The objective of this study was to develop, verify, and validate a new GIS-based model for simulating the fate and transport of rice pesticides in river basins. A plot scale model simulating pesticide fate and transport in rice paddies (PCPF-1) was incorporated into the Soil and Water Assessment Tool (SWAT) basin scale water and pollutant transport model. The new combined model, PCPF-1@SWAT model, was first used on some base-case scenarios to verify that the PCPF-1 algorithm and the routing of variables were correctly implemented. Next, the PCPF-1@SWAT model was calibrated and validated on the Sakura River basin (Ibaraki prefecture, Japan) using mefenacet concentrations measured during the rice growing season in 2008. The modeling procedures for simulating pesticide fate and transport in a Japanese river basin were demonstrated by providing model parameters related to hydrology, land use, pesticide fate, and rice field managements methods. The water flows predicted by the PCPF-1@SWAT model in the Sakura River basin were accurate throughout the whole simulation year, with R 2 and E NS statistics exceeding 0.74 and 0.71, respectively for daily flow. The use of different seepage rates had appreciable influence on the simulations. High seepage rates gave a slight overestimation of the predicted base flow during the rice growing period, whereas the base flow predictions using lower seepage rates were comparable to measured data. The PCPF-1@SWAT model successfully simulated the fate and transport of mefenacet in the Sakura River in which measured mefenacet concentrations peaked soon after the initial herbicide application in May, and decreased gradually during the months of June and July. Occasional major precipitation events caused the mefenacet concentration in streams to peak quickly due to a corresponding loss of mefenacet from paddy areas, and then rapidly decrease due to dilution by excess rainfall discharge. The simulation using a seepage rate of 0.12 cm day À1 had the most accurate prediction of mefenacet concentration in river water with an R 2 of 0.61 and an E NS of 0.65.

Agriculture is the main occupation in India. Growing demand for food or a result of increasing population has led to a substantial increase in the production of agrochemicals like pesticides and fertilizers resulting in a continued contamination of environment including water bodies. The Lysimeter will allow us to better monitor below ground processes and measurements of nutrients, pesticides, and moisture content with minimal disturbance, both of which are extremely difficult to perform in the field. The Lysimeter were made up of cast iron, 1.2m diameter, and 1.5m length. Ports were provided at each depth of 0.5m to collect samples up to 1.5m. Lysimeter is installed in field in undisturbed condition. The experiment was initiated in June 2009 at the krishi vigyan Kendra farm (kupparvalli, suttur, Nanjangud). Lysimeter were used to study the leaching of fertilizers and pesticides in paddy field. The leachate samples collected from the field (Lysimeter) were analyzed for nitrate, phosphate, pH, conductivity, and Chlorpyriphos. Chlorpyriphos concentration showed a decreasing trend with depth this is may be due to reason as the pesticide moves through the soil it gets absorbed by organic carbon and degraded by the micro-organism.

An astonishing 150 million tons of fertilizers and 6 million tons of pesticides are yearly and routinely applied to fields and crops with the purpose of increasing agricultural production. Today modern agriculture relies heavily on the use of pesticides. Hence, instilling confidence and enriching farmers begins with recognizing the need for pesticide use modification, whether through existing or new technologies, such as efficiency, cost reduction or effective decision-making. As many types of rapid toxicity or explicit evidence and platforms provide useful information on the symptoms of human risk and pesticide self-poisoning accounts, which offer the promise of aiding decision-making in a variety of areas, including the regulatory management of chemicals, product, environmental assessment and emergencies. The aim of the present study was to assesses commonly used pesticides application and frequency of farmer’s self-reported symptoms in Kano State, Nigeria. A comprehensive questionnaire was established that focuses on sociodemographic characteristics, education and experience on the adverse health effects associated with the use of the pesticide, description of job practices and a list of used pesticides on the farms in the study area. Of the 400 copies of the administered questionnaires, 392 copies were retrieved and found useable, which represents 98% of the administered questionnaires. A total of 89.5% of the farmers make use of pesticides; of the 351 farmers that made use of pesticides, 31.3% use Apron plus, 12.0% use Atrazine, 33.6% use [Cypermethrin] while 9.7%, 8.5%, 4.8%, 31.3% and 12.0% of the respondents use Sevin, Thiodan, Fusilade, Primextra and others respectively, of the farmers 46.2% had been using the pesticide for 1-5 years, 48.1% had used it for 10-15, regularity of these symptoms reveals that the majority of the respondents experienced these symptoms on a regular basis (56.1% for headache, 53.8% for stomach cramps, 56.5% for muscles weakness, 56.8% for vomiting, 58.3% for dizziness, 40.7% for shortness of breath, 45.5% for blurred vision and 66.7% for eye irritation. It is therefore imperative to focus on chemical pesticides and their toxicity, which should be assessed quickly and new methods should be develop to prioritize human and biological health. Also, structured interventions are required to lessen health risks exposure, as well as training, labeling improvements, and measures to decrease the cost of barriers in the implementation of safety behaviors and promotion of administrative control measures. Likewise, the use of integrated pest management (IPM) strategies in emerging countries such as Nigeria should be encouraged and made possible by a wide variety of public initiatives through translating local data into evidence-based solutions at a grassroots level. Thus, calling for action for local scale participatory citizen science to solve complex chemical pesticides issues at a local, regional, and national scale.

This work is within the framework of a project where the overall objective is to create the methodology for a sustainable management of an important wetland in Argentina, "Esteros del Ibera". Rice culture has been identified as the main anthropogenic activity, being necessary to evaluate the impacts of pesticides used in rice culture on the aquatic ecosystem. The purpose of this paper is to evaluate the impacts of pesticides used in rice culture through the use of a Mackay's model, to identify the potentially more contaminated environmental compartments, and identify their toxicological and physicochemical properties. Based on the results of the model, water samples were collected and two insecticides (endosulfan and carbofuran) were analysed using the solid-phase microextraction (SPME) extraction technique with detection by gas chromatography with mass spectrometry (GC-MS). To create a decision tool based on monitorization results, pesticide guidelines for water quality (drinking and for aquatic life protection) were calculated and compared with the available international regulations for pesticides; conservative guidelines are recommended. The results of pesticides analysis were compared with these guidelines; some results exceeded the international guidelines (mainly the values for protection of aquatic life) in particular those from samples taken close to the discharge points and due to the presence of the more toxic insecticide endosulfan; however, the impact of pesticides on most waters of the lagoon Ibera seems not yet to be very significant, but monitoring of impacts and careful use of pesticides, specially insecticides, should be observed in the future.

Propargyl bromide (3-bromopropyne, 3BP) is a potential alternative for methyl bromide. Little information is available about its efficiency in controlling pests. The purpose of this paper is to estimate the 3BP dose required for killing three pests and to compare the efficiency of water management approaches to that of fumigation. The pests, Fusarium oxysporum Schlecht (fungus), Echinochloa crus-galli (L) Beauv (grass) and Tylenchulus semipenetrans Cobb (nematode) were exposed to different 3BP concentrations in a sandy loam at 30 • C in a closed system. The lethal dose for killing 90% of the population (LD 90 ) was calculated from the total applied mass, and varied from 0.3 µg g −1 soil for the nematode, 3 µg g −1 for the grass, and 9 µg g −1 for the fungus. The concentration-time index for killing 90% of the population (CT 90 ) was 11 µg g −1 h for the nematode, 112 µg g −1 h for the grass and 345 µg g −1 h for the fungus. 3BP seems as efficient as other fumigant alternatives in controlling these pests. Using an open system, it was shown that the volume of soil in which the pests were controlled varied for different irrigation managements. Even 96 h after fumigation (with a concentration 10 times higher than would potentially be applied in the field), more than 20% of the soil volume had not reached the fungus and grass CT 90 of the non-irrigated soil. The soil underneath the furrow and the bed reached CT 90 only slowly in all irrigated treatments even though techniques for increasing efficiency were used (tarping, surface sealing with water and high application rate).

Screening methods are required in order to determine which pesticides should receive greatest attention with respect to environmental problems. Several authors have proposed screening methods for determining whether a pesticide is likely to leach to groundwater. The Groundwater Ubiquity Score (GUS) developed by GUSTAFSON (5) has been used, as the first step of a tiered approach for specifying which chemicals should deserve longer attention and expensive studies of leachability. However, GUS is empirically based and has a deficiency due to the prediction of anomalous negative values for pesticides with short half-life and/or large sorption coefficient. In the present work, it was developed a method for evaluating the leachability denominated index LIX as simple as index GUS however enabling faster and better visualization and interpretation of results.

Insekticid tiakloprid, ki smo ga pridobili iz komercialnega produkta Calypso® 480 SC (Bayer) namenjenega zatiranju uši na sadnem drevju, je le eden izmed mnogih onesnaževal pogosto uporabljenih v kmetijstvu. Danes že skoraj vsakdo pozna probleme onesnaženosti okolja, s katerimi se spopada sodobna družba, pri čemer so onesnažene vode, tako podtalnica kot površinski vodotoki in jezera, eden najbolj perečih problemov, ki že predolgo čakajo na reševanje.
Tiakloprid je obstojen in se brez (foto)katalizatorjev v vodi le počasi razkraja, imobiliziran TiO2, ki ga v obliki tankih plasti, v sklopu različnih projektov, za širšo (komercialno) uporabo razvijajo v Laboratoriju za raziskave v okolju (LRO) na Univerzi v Novi Gorici, in Fe(II/III) v foto-Fentonovem procesu, ki naj bi že potekal v naravi, sta samo dve izmed možnih rešitev. V primeru prvega gre za heterogeno katalizo (katalizator in polutant v različnih agregatnih stanjih), v primeru drugega pa homogeno (katalizator in onesnaževalo v enakem agregatnem stanju).
Fotorazgradnjo prej navedenega insekticida z uporabo obeh katalizatorjev sem testiral v posebnem novem fotoreaktorju Carberry-vega tipa pri različnih pH-jih in dobil sledeče rezultate:
- Fe(II/III) v foto-Fentonovem procesu se je izkazal kot učinkovitejši fotokatlizator od imobiliziranega TiO2 .
- Tudi imobiliziran TiO2 je učinkovit katalizator, razvoj tehničnih rešitev za njegovo uporabo v vodo-prčiščevalnih sistemih pa že poteka.
- Sinergija med katalizatorjema lahko bila prisotna le takrat, ko bi bil prebitkek Fe3+ ionov, kajti sicer oksidacija Fe(II) v Fe(III) onemogoča delovanje tankih plasti TiO2.

This work is within the framework of a project where the overall objective is to create the methodology for a sustainable management of an important wetland in Argentina, “Esteros del Ibera”. Rice culture has been identified as the main anthropogenic activity, being necessary to evaluate the impacts of pesticides used in rice culture on the aquatic ecosystem. The purpose of this paper is to evaluate the impacts of pesticides used in rice culture through the use of a Mackay's model, to identify the potentially more contaminated environmental compartments, and identify their toxicological and physicochemical properties. Based on the results of the model, water samples were collected and two insecticides (endosulfan and carbofuran) were analysed using the solid-phase microextraction (SPME) extraction technique with detection by gas chromatography with mass spectrometry (GC–MS). To create a decision tool based on monitorization results, pesticide guidelines for water quality (drinking and for aquatic life protection) were calculated and compared with the available international regulations for pesticides; conservative guidelines are recommended. The results of pesticides analysis were compared with these guidelines; some results exceeded the international guidelines (mainly the values for protection of aquatic life) in particular those from samples taken close to the discharge points and due to the presence of the more toxic insecticide endosulfan; however, the impact of pesticides on most waters of the lagoon Ibera seems not yet to be very significant, but monitoring of impacts and careful use of pesticides, specially insecticides, should be observed in the future.

Residues of methyl parathion, fenitrothion, malathion and endosulfan were determined in various parts of rice plant using gas liquid chromatography. The decline of residues were followed for 15 days in leaves and in harvested whole grain and. dehusked grains. Effect of sun drying and par boiling of rice, on the reduction of residues was also studied. Factors influencing the residues are correlated. The decline of these pesticide levels in the leaves although fast are still above environmental protection agency tolerance limits even after 15 days. The same is true with whole grain and dehuskod grain and hay immediately after harvest. However sun drying and par boiling the rico reduces the residues to 90~o. of residues by sun drying; par boiling.

The decay characteristics and erosion-related transport of glyphosate and aminomethylphosphonic acid (AMPA) were monitored for 35 d at different slope gradients and rates of application in plots with loess soil on the Loess Plateau, China. The initial glyphosate decayed rapidly (half-life of 3.5 d) in the upper 2 cm of soil following a firstorder rate of decay. AMPA content in the 0-2 cm soil layer correspondingly peaked 3 d after glyphosate application and then gradually decreased. The residues of glyphosate and AMPA decreased significantly with soil depth (p b 0.05) independently of the slope inclination and application rate. About 0.36% of the glyphosate initially applied was transported from plots after one erosive rain 2 d after the application. Glyphosate and AMPA concentrations in runoff were low while the contents in the sediment were much higher than in the upper 2 cm of the soil. Capsule: Although the rate of glyphosate decay is rapid in Chinese loess soil, the risks of glyphosate and AMPA need to be taken into account especially in the area with highly erosive rainfall.

2007. Automation and evaluation of three pesticide fate models for a national analysis of leaching risk in Canada. . Under the National Agri-Environmental Health Analysis and Reporting Program (NAHARP), pesticide fate models are being used to develop an indicator of risk of water contamination by pesticides (IROWC-Pest) in Canada. The large number of model runs needed for a national analysis of the risk of pesticide leaching to ground water required the development of a computer program, AutoPFM (Automate Pesticide Fate Model), to automate the running of pesticide fate models. Using Manitoba as a test province, and the selected pesticide fate models PRZM, LEACHP, and MACRO, AutoPFM permitted the estimation of the leaching potential of the fourteen most used agricultural pesticides in Manitoba. Assuming an application rate of 300 g ha -1 for each pesticide, only six pesticides demonstrated leaching across most soil series. For these six pesticides, there was significant correlation in how PRZM and LEACHP ranked the leaching potential of 337 Manitoba soil series. Because of its long run times, the estimation of leaching potential with MACRO was limited to two pesticides (2,4-D and MCPA). For these pesticides, MACRO showed significant correlation with the PRZM and LEACHP in ranking the soil series. Based on the results described in this paper, PRZM was chosen as the pesticide leaching model for use in IROWC-Pest. McQueen, D. A. R., Farenhorst, A., Allaire, S. et Cessna, A. J. 2007. Automatisation et évaluation de trois modèles sur le devenir des pesticides dans le cadre d'une analyse nationale des risques de lixiviation au Canada. Can. J. Soil Sci. 87: 203-212. Le Programme national d'analyse et de rapport en matière de santé agroenvironnementale (PNARSA) recourt à des modèles sur le devenir des pesticides pour l'élaboration d'un indicateur des risques de contamination de l'eau par les pesticides (IRCE-Pest) au Canada. Le grand nombre de simulations requises pour analyser les risques de lixiviation des pesticides dans la nappe phréatique à l'échelon national a nécessité la création du logiciel AutoPRF (Automate Pesticide Fate Model) qui automatise l'application des modèles précités. En prenant le Manitoba comme cobaye et en appliquant les modèles PRZM, LEACHP et MACRO, le logiciel AutoPFM a permis d'estimer les risques de lixiviation des quatorze pesticides les plus employés au Manitoba.

Introduction: The occupational toxic risks from agricultural activities in El Salvador affect human and environmental health. The objective of this paper is to describe the management of pesticide by farmers confirmed with a chronic kidney disease of uncertain etiology (CKDu) not associated to diabetes mellitus or hypertension. Methods: The study involved 42 male patients older than 18 years old with confirmed CKDu that have participated in different stages of pesticides management. This is a cross-sectional study; it was conducted from January to June 2011, in three communities of Bajo Lempa region, El Salvador. An interview was especially designed to investigate which pesticides were used and the farmer practices at different stages of pesticide use. Statistical descriptive analysis was carried out for the several studied variables. Results: All interviewed people had a direct relationship with agricultural activities. The majority of patients had poor education, 19% were illiterate and 55% only have primary education. Most farmers with CKDu had been exposed more than 10 years to hazardous pesticides. The most used pesticide was Hedonal/2, 4 D (100%). 95% interviewed patients mixed different pesticides and 63% dumped empty pesticide containers in the fields. Interviewees did not use appropriate personal protective equipment (100%). Conclusions: There is high use of hazardous pesticides by patients and some of these are banned and some are legal in El Salvador, but prohibited by other countries. Interviewed CKDu patients had high exposure to toxic pesticides due to the misuse in almost all stages. There is inadequate legislation and a poor law enforcement to prevent the misuse of pesticides in El Salvador.

A survey was conducted in several Ecuadorian banana plantations to determine the actual pesticide management and their environmental impacts. It was detected that Glyphosate, Propiconazole, Imazalil, Tridemorph and Imazalil are the pesticides most used in the Ecuadorian banana sector. As a first step, two screening models (EQC and EXAMS) were used to determine the overall distribution of these pesticides in a unitary environment. Whereas EQC evaluates soil, water, sediment and air compartments, EXAMS only takes into account water and sediment compartments. Although both models show different results due to their different approaches, a comparison can still be done considering only the aquatic portion of the unitary environment. For the case study presented here, all 5 pesticides tend to affect more the soil and water compartment.