PLAYING THE TRUMP OF DUALITY IN DISCUSS: UPGRADING POCER WITH QUESTIONNAIRE RESULTS

DISCUSS, the Dual Indicator Set for Sustainable Crop protection Sustainability Surveys, was designed to help farmers achieve more sustainable crop protection. The indicator set pairs risk indicators--POCER--, with response indicators--a management questionnaire. Both parts of DISCUSS are indicators in their own right, but the dual risk-response setup has the additional trump that the questionnaire reveals farm level information, by which POCER calculations are refined. Simulations with personal protection and drift mitigation measures illustrate how DISCUSS can be used to support the farmers' crop protection decisions.

Influence of surfactants on the sorption of two chloroacetanilide in an Romanian chernozem soil

Pesticides have been extensively used in modern agriculture. Due to the prevalent use, there have been serious problems generated by pesticides wastes which could eventually endanger water resources and human health. The development of technologies for the decontamination of soils and waters polluted by hydrophobic organic compounds has encouraged research into the use of non-ionic surfactants as potential agents for the enhanced solubilization and removal of contaminants from soils and sediments. Sorption of two chloroacetanilide herbicides, acetochlor and metolachlor was studied on a representative chernozem soil of the Main Agricultural Research Station Ezareni belonging to the "Ion Ionescu de la Brad" University of Agriculture and Veterinary Medicine lasi, Romania, in the presence and absence of surfactants. Three different non-ionic surfactants were selected: Tween-20, Synperonic 91/5 and Silwet L-77, to verify the influence of their presence on herbicide sorption at different concentrations. Our results showed that the sorption of the studied herbicides within the soil-water-non-ionic surfactant system was influenced by the presence of non-ionic surfactants. The n values obtained were lower than 1 for all pesticide-surfactant combinations, which indicates that the amount of acetochor and metolachlor sorbed decreased with an increase in pesticide concentration. The sorption of acetochlor increased in the following order: Acetochlor+Synperonic 91/5 < Acetochlor < Acetochlor+Tween-20 < Acetochlor+Silwet L-77. In the case of metolachlor+Synperonic and metolachlor+Silwet L-77, the Kf values were significantly higher than the Kf value of metolachlor+Tween-20 on soil, where a lower Kf value could be observed with however a higher n value which indicate a higher sorption capacity at higher concentrations.

Risk assessment of oncogenic potency of pesticide residues in fruits and vegetables

Pesticides are used in agriculture to improve food security by assuring good harvest, however, they can have harmful effects in human beings and animals. One of the harmful effects of pesticides is their carcinogenicity. Exposure to oncogenic compounds may result in cancer to the exposed animal or person. In this paper, exposure assessment of oncogenic potency of pesticides was performed from raw and processed fruits and vegetables. The oncogenic risk was calculated by multiplying the estimated daily intake (EDI) of the pesticide residue with the oncogenic potency factor (Q*) of the concerned pesticide. The total potential oncogenic risk was calculated to be 2.76 x 10(-3) before processing and 8.97 x 10(-4) after processing. The risk was higher than the EPA acceptable limit of 1 x10(-6). Despite the calculated levels exceeding the EPA acceptable limit, food processing activities reduced the dietary oncogenic risk to an average 33.8%.

Optimizing the application of entomopathogenic nematodes: experimental set-up

The complex issue concerning the spray application of Entomopathogenic Nematodes (EPNs) with a hydraulic sprayer is still not solved. This research project focuses on the effect of spray application technique on the viability and deposition of EPNs. In this paper the experimental set-up used for this evaluation is described. A modular spray application system has been developed and is currently used to evaluate the effect of different parts of a sprayer on the viability of the EPNs. Based on the results of experiments using this modular spray application system, recommendations regarding pump type, mixing system, nozzle type and filter size will be formulated. Because of the large number of experiments in this research project, an image analysis system for the determination of the viability of the nematodes is developed. This paper describes two experiments comparing the new developed image processing technique with the standard microscopic counting technique.

Optimizing the application of entomopathogenic nematodes

A wide range of susceptible insect species encourages the wider use of Entomopathogenic Nematodes (EPNs) as biological insecticides in plant production. So far, the complex expertise concerning the application of EPNs with a hydraulic sprayer is far from complete. At present there are a few guidelines on how biopesticides should be applied to optimize their performance in the field or in the glasshouse. Such guidelines are essential to obtain a good efficacy of the EPN products and to encourage the acceptance and use of biopesticides by growers. This article is a description of the first part of a recently started Ph.D.-research. This research will focus on the effect of spray application technique on the viability and deposition of EPNs (first part). Also the effect of different formulation types and the interaction of formulation and application technique on the viability of EPNs will be investigated (second part). Based on the results of experiments using a modular spray application system, recommendations regarding pump type, mixing system, nozzle type and formulation will be made.

The assessment of spray drift damage for ten major crops in Belgium

According to the Council Directive 91/414/EC pesticide damage should be assessed by considering the risk for persons arising from occupational, non-dietary exposure and risk to the environment. In this research an assessment for the pesticide damage by droplet spray drift was set up. The percentages of spray drift were estimated with the Ganzelmeier drift curves and the IMAG drift calculator. Knowing the percentages of drift and the applied doses of pesticide formulations in a given crop, the human and environmental exposures (water and bottom) were predicted. Thereupon risk indices were calculated for water organisms, soil organisms and bystanders. A risk index is the ratio of a predicted exposure to a toxicological reference value and gives an indication of the incidence and the severity of the adverse effects likely to occur. Considering the risk index it is possible to define the minimal width of an unsprayed field margin or "buffer zone" to reduce this risk at an acceptable level.

Spray drift as affected by meteorological conditions

Spray drift can be defined as the quantity of plant protection product that is carried out of the sprayed (treated) area by the action of air currents during the application process. This continues to be a major problem in applying agricultural pesticides. The purpose of this research is to measure and compare the amount of drift for different climatological conditions under field conditions. Spray drift was determined by sampling in a defined downwind area at different positions in a flat meadow using horizontal drift collectors (sedimenting spray drift) and pipe cleaners (airborne spray drift) for a reference spraying. Meteorological conditions were monitored during each experiment. A drift prediction equation for the reference spraying was set up to predict the expected magnitude of sedimenting drift at various drift distances and atmospheric conditions (wind speed and temperature). This equation can be used to compare measurements using other spraying techniques under different weather conditions to the reference spraying. In 2005, more measurements will be performed to validate the statements and the model reflected in this paper.

Environmental impact of adjuvants in crop protection

The overall performance of chemical and biological plant protection products is enhanced by the use of adjuvants in the formulation (formulation adjuvants) or in the spray tank (spray adjuvants). Both types of adjuvants aim to stabilize the formulation, to improve the efficiency of the active ingredients and to reduce application and environmental risks. As an important part of the formulation, both quantitatively and qualitatively, the environmental impact and toxicology of adjuvants can not always be considered as inert. However, little is known of their impact as part of plant protection products compared with the active substances. Therefore an experimental framework is needed as a tool for a consistent environmental legislation.

A pdpa laser-based measuring set-up for the characterisation of spray nozzles

The characteristics of agricultural sprays belong to the most critical factors affecting spray drift, deposition on plants, spray coverage and biological efficacy. Hence, within the framework of a research project about agricultural spray drift, a measuring set-up for the characterisation of spray nozzles using a Phase Doppler Particle Analyser (PDPA) was developed. This set-up is able to measure droplet sizes and velocities based on light-scattering principles. It is composed of different parts i.e.: a climate room, a spray unit, a three-dimensional automated positioning system and an Aerometrics PDPA 1D system. This paper presents a detailed description of this measuring set-up along with some first measuring results. These measurements will be used as an input for a Computational Fluid Dynamics drift-prediction model and to classify nozzles based on their driftability.

Pesticides in rainwater in Flanders, Belgium: results from the monitoring program 1997-2001

In 1997 the Flemish Environmental Agency (FEA) started a monitoring program "Pesticides in Rain in Flanders, Belgium". The original purpose of the monitoring program was to examine the possible occurrence of dichlorvos in rainwater and subsequent deposition. However, it was thought necessary from the beginning to monitor a wide range of pesticides. During the first year some 62 pesticides and metabolites and 9 polychlorinated biphenyls, were monitored at 4 locations. Nowadays the monitoring program has grown up to more than 100 pesticides and metabolites and 11 polychlorinated biphenyls examined at 8 different locations. Rainwater is collected continuously and samples are examined for pesticides and PCB's on a weekly basis. In agreement with other European studies pesticides are found in rainwater samples during times of application. Pesticides which are most frequently detected are [small alpha]-, [small beta]-endosulfan and endosulfan sulfate, [gamma]-HCH (lindane), dichlorvos, atrazine, diuron, DNOC, glyphosate and AMPA and isoproturon. Furthermore it was seen that most pesticides showed a deposition pattern related to local spraying operations.

Wind tunnel evaluation of several tracer and collection techniques for the measurement of spray drift

In the history of pesticide drift measuring techniques, different tracers and a lot of different collection techniques have been used. At the start of a new Flemish project 'Protecting the Flemish environment against drift - The importance of drift-reducing techniques', wind tunnel tests have been executed to select the most efficient tracer and collection technique. As tracer types a fluorescent tracer Renaissance W15, 2 different chelates, a NaCl-solution and a fungicide Tolylfluanide were used. 2 different collection techniques were tested: drains incorporated in the wind tunnel floor filled with filter paper and filled with cloths. The recovery of the different tracers combined with the 2 collection materials was calculated. The advantages and disadvantages of the tracers and collection materials are enumerated in this article.

Limitation of point source pesticide pollution: results of bioremediation system

Groundwater and surface water is at risk of contamination from the use of some agricultural pesticides. In many circumstances pesticide contamination of water resources is more likely to result from point sources than from diffuse sources following approved application to crops in the field. Such point sources include areas on farms where pesticides are handled, filled into sprayers or where sprayers are washed down. To overcome this way of contamination different kind of bio-remediation systems are nowadays in development. In Flanders, Belgium two pilot plants of bioremediation systems for the in situ retention and/or degradation of pesticides were installed. Both systems were based on the Phytobac concept, a watertight excavation filled with straw, peat, compost and soil. The channel was made in the bottom from plastic foil. All kinds of spray rests were captured by the phytobacs. This study focuses on what level pesticides leach, bio-degrade or are retained by the filling of the phytobac. The soil-properties of the filling were investigated. Pesticide tracers were added for monitoring to both phytobacs. Soil and water samples were taken during one year. Pesticides are retained at least for one month by the filling of the phytobac. Almost no pesticide leached out. In winter hardly any pesticide degradation was observed in the filling of the phytobac. In summer no detectable pesticides were still left in the phytobacs.

The effect of adjuvants on atomisation of pesticides

Four surfactants Tween 20, Agral 90, Silwet L77 and Break Thru, commonly used in the formulations of agricultural products, were evaluated on their spray performance and dynamic surface tension. In a spray test the Dv 50 (micron) or the Volume Median Diameter and the percentage of droplets with diameter below 100 microns (drift sensitive droplets), were measured for different kind of nozzles varying from the classical flat fan up to the low drift nozzles. The spectra changed considerably when different kind of nozzles and different kind of surfactants were used, the concentration effect was less important. The dynamic tension of the different surfactant solutions could not always explain the changes in droplet spectrum.

POCER, a new pesticide risk indicator

POCER, the pesticide occupational and environmental risk indicator, has been developed in order to be able to quantify the health and environmental risk from the use of pesticides in agriculture. The POCER indicator is used as a decision tool to rank and choose between alternative pesticides, to evaluate the effect of certain pesticide reduction measures and to evaluate the effectiveness of policy measures. The practical use of the indicator is explained using examples.

Simulation of drift of pesticides: development and validation of a model

Over the last decade drift of pesticides has been recognized as a major problem for the environment. High fractions of pesticides can be transported through the air and deposited in neighbouring ecosystems during and after application. A new computer-two steps-drift model is developed: FYDRIMO or F(ph)Ysical DRift MOdel. In the first step the droplet size spectrum of a nozzle is analysed. In this way the volume percentage of droplets with a certain size is known. In the second step the model results in a prediction of deposition of each droplet with a certain size. This second part of the model runs in MATLAB and is grounded on a combination of two physical factors: gravity force and friction forces. In this stage of development corrections are included for evaporation and wind force following a certain measured wind profile. For validation wind tunnel experiments were performed. Salt solutions were sprayed at two wind velocities and variable distance above the floor. Small gutters in the floor filled with filter paper were used to collect the sprayed droplets. After analysing and comparing the wind tunnel results with the model predictions, FYDRIMO seems to have good predicting capacities.

Pesticide residue concentrations in the Belgian total diet, 1991-1993

In the period 1991-1993, an official study was conducted to measure the presence and evaluate the risk of pesticide residues in plantbased food in the Belgian total diet. Positive samples were subjected to one or more culinary treatments (washing, peeling, steaming, or cooking) to determine the decrease of residues in prepared ready-to-eat food. Thus, better estimates of pesticide residues taken up through consumption were determined and compared with toxicological criteria. Washing did not significantly reduce residues. Peeling fruits removed almost all pesticides. The effects of cooking and steaming varied, depending on the type of food and pesticide.

Monitoring of pesticide residues in fresh vegetables, fruits, and other selected food items in Belgium, 1991-1993

To estimate the exposure of the Belgian population to food contaminated with pesticide residues and to determine what pesticides people are actually consuming, a total diet study-individual approach-was performed. Fourteen kinds of fruits, 22 kinds of vegetables, and 7 other food items (coffee, drinking water, rice, tea, wine, bran, and wheat flour) were selected as major representatives of the Belgian diet. During the 2 years of study (April 1991-March 1993), about 3,698 samples were analyzed and 21 163 analyses were performed. The first part of this study demonstrates that no residues are found in 31.3% of leafy vegetables, 72.3% of other vegetables, 51.4% of fruits, and 67.2% of other samples. In particular cases, some critical situations still exist, especially for leafy vegetables. Also, contamination of foreign samples is not easy to determine, because origins are not always traceable.

Residues of quintozene, its contaminants and metabolites in soil, lettuce, and witloof-chicory, Belgium--1969-74

Authors studied contamination of soils used to raise lettuce in greenhouses and witloof-chicory (French endive) in forcing beds. The crops had been treated with the fungicide quintozene; residues detected included quintozene, its technical impurities and metabolites hexachlorobenzene, pentachlorobenzene, pentachloroaniline, and pentachlorothioanisole. Analyses of 72 soil samples indicated that soils remain contaminated with these chemicals one or more years after application. This is attributed to the high persistence of quintozene, its impurities and metabolites, and the almost annual application of the fungicide. Analyses of the crops show that quintozene, hexachlorobenzene, and pentachloroaniline are taken up from contaminated soils, especially by lettuce. Pentachlorothioanisole, although present in the soils, was not detected in the crops.