Agricultural contaminants in amphibian breeding ponds: Occurrence, risk and correlation with agricultural land use.

Anthropogenic pressure such as agricultural pollution globally affects amphibian populations. In this study, a total of 178 different compounds from five agrochemical groups (i.e. antimicrobial drugs residues (ADRs), coccidiostats and anthelmintics, heavy metals, mycotoxins and pesticides) were determined monthly, from March until June 2019 in 26 amphibian breeding ponds in Flanders, Belgium. Furthermore, a possible correlation between the number and concentration of selected contaminants that were found and the percentage of arable land within a 200 m radius was studied. Within each group, the highest detected concentrations were obtained for 4-epioxytetracycline (0.422 µg L-1), levamisole (0.550 µg L-1), zinc (333.1 µg L-1), 3-acetyldeoxynivalenol (0.013 µg L-1), and terbuthylazine (38.7 µg L-1), respectively, with detection frequencies ranging from 1 (i.e. 3-acetyldeoxynivalenol) to 26 (i.e. zinc) out of 26 ponds. Based on reported acute and chronic ecotoxicological endpoints, detected concentrations of bifenthrin, cadmium, copper, cypermethrin, hexachlorobenzene, mercury, terbuthylazine, and zinc pose a substantial ecological risk to aquatic invertebrates such as Daphnia magna and Ceriodaphnia dubia, which both play a role in the food web and potentially in amphibian disease dynamics. Additionally, the detected concentrations of copper were high enough to exert chronic toxicity in the gray treefrog (Hyla versicolor). The number of detected compounds per pond ranged between 0 and 5 (ADRs), 0 - 2 (coccidiostats and anthelmintics), 1 - 7 (heavy metals), 0 - 4 (mycotoxins), and 0 - 12 (pesticides) across the four months. Furthermore, no significant correlation was demonstrated between the number of detected compounds per pond, as well as the detected concentrations of 4-epioxytetracycline, levamisole, copper, zinc, enniatin B and terbuthylazine, and the percentage of arable land within a 200 m radius. For heavy metals and pesticides, the number of compounds per pond varied significantly between months. Conclusively, amphibian breeding ponds in Flanders were frequently contaminated with agrochemicals, yielding concentrations up to the high µg per liter level, regardless of the percentage surrounding arable land, however showing temporal variation for heavy metals and pesticides. This research also identifies potential hazardous substances which may be added to the European watch list (CD 2018/408/EC) in the future.

Toxicity and Metabolism of Zeta-Cypermethrin in Field-Collected and Laboratory Strains of the Neotropical Predator Chrysoperla externa Hagen (Neuroptera: Chrysopidae).

Resistance to pesticides has been studied in several insect pests, but information on the natural enemies of pests-including the Neotropical predator Chrysoperla externa Hagen (Neuroptera: Chrysopidae), a major biological control agent in South America-is lacking. We report here a comparative study between a field-collected strain of C. externa subjected to monthly sprayings of pyrethroids and neonicotinoids and a laboratory strain without exposure to pesticides. The tolerance of both strains against zeta-cypermethrin was similar, and addition of the synergist piperonyl butoxide increased the toxicity by 30% in both strains. Gas-chromatography analyses and mixed-function-oxidase measurements indicated similar values in both strains and also confirmed the key role of oxidative metabolism in this species. Because C. externa has maintained a tolerance to zeta-cypermethrin without previous pesticide exposure, this species could potentially be mass-reared and released in fields in the presence of pesticide pressure.

Modelling exposure of workers, residents and bystanders to vapour of plant protection products after application to crops.

Agricultural use of plant protection products can result in exposure of bystanders, residents, operators and workers. Within the European Union (EU) FP7 project BROWSE, a tool based on a set of models and scenarios has been developed, aiming to assess the risk of exposure of humans to these products. In the present version of the tool only a first conservative tier is available for outdoor vapour exposure assessment. In the vapour exposure evaluation, the target concentrations in air at 10m distance from the edge of a treated field are calculated for specific scenarios for each EU regulatory zone. These scenarios have been selected to represent reasonable worst case volatilisation conditions. The exposure assessment is based on a series of weekly applications in a five year period to cover a wide range of meteorological conditions. The volatilisation from the crop is calculated using the PEARL model and this PEARL output provides the emission strength used as input for the short term version of the atmospheric transport model OPS. The combined PEARL-OPS model is tested against measurements from a field experiment. First results of this test show that the mean concentration level was predicted fairly well. However, sometimes the differences between observations and simulations were found to be substantial. Improvements are suggested for the vapour exposure scenarios as well as for further model development. In the current version of the BROWSE tool a simplified procedure is used to assess single and multiple applications. The actual period of application and the time of application during the day are fixed, and the growth stage of the crop cannot be taken into account. Moreover, competing processes such as penetration of the substance into the plant tissue are not considered. The effect of these factors on the target exposure concentrations is discussed.

Perceptions of pesticides exposure risks by operators, workers, residents and bystanders in Greece, Italy and the UK.

The EU Directive on the sustainable use of pesticides (EU128/2009/EC) requires European Member States to develop training activities targeting occupational exposure to pesticides, and communication material aimed at residents and bystanders. Risk perceptions, knowledge and attitudes associated with passive and occupational exposure to pesticide potentially influence the extent to which different stakeholders adopt self-protective behaviour. A methodology for assessing the link between attitudes, adoption of self-protective behaviours and exposure was developed and tested. A survey was implemented in the Greece, Italy and the UK, and targeted stakeholders associated with pesticide exposure linked to orchards, greenhouse crops and arable crops respectively. The results indicated that the adoption of protective measures is low for residents and bystanders, with the exception of residents in Greece, when compared to operators and workers, who tend to follow recommended safety practices. A regression analysis was used to examine the factors affecting the probability of adopting protective measures as well the as the level of exposure in the case of operators and workers where data are available. The results indicate that the likelihood of engaging in self-protective behaviour is not significantly affected by perceptions of own health being affected by pesticides for residents and bystanders. However, operators who perceive that their heath has been negatively affected by the use of pesticides are found to be more likely to adopt self-protective behaviours. Gender and country differences, in perceptions, attitudes and self-protection are also observed. Recommendations for improved communication, in particular for vulnerable groups, are provided.

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.

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%.

Effects of food processing on pesticide residues in fruits and vegetables: a meta-analysis approach.

Pesticides are widely used in food production to increase food security despite the fact that they can have negative health effects on consumers. Pesticide residues have been found in various fruits and vegetables; both raw and processed. One of the most common routes of pesticide exposure in consumers is via food consumption. Most foods are consumed after passing through various culinary and processing treatments. A few literature reviews have indicated the general trend of reduction or concentration of pesticide residues by certain methods of food processing for a particular active ingredient. However, no review has focused on combining the obtained results from different studies on different active ingredients with differences in experimental designs, analysts and analysis equipment. In this paper, we present a meta-analysis of response ratios as a possible method of combining and quantifying effects of food processing on pesticide residue levels. Reduction of residue levels was indicated by blanching, boiling, canning, frying, juicing, peeling and washing of fruits and vegetables with an average response ratio ranging from 0.10 to 0.82. Baking, boiling, canning and juicing indicated both reduction and increases for the 95% and 99.5% confidence intervals.

Interception of spray drift by border structures. Part 1: wind tunnel experiments.

This research investigated the drift-intercepting potential of structures surrounding the field borders, like artificial screens and crops, which are not yet a part of the drift mitigation measures for field crop sprayers in Belgium. Drift-interception experiments were performed in the wind tunnel of the International Centre for Eremology (Ghent University, Belgium) with various interception structures: Artificial screens with heights of 0.5, 0.75 and 1 m and screen open areas of 16, 36 and 63%; a row of plastic Christmas trees with heights of 0.5 and 0.75 m; and a potato canopy. The interception structure was positioned at 1 m from the field border. From the results it was found that type of border structure has a pronounced effect on the drift interception, while the height of the border structure had no significant effect.

Interception of spray drift by border structures. Part 2: field experiments.

This research studied the effect of drift-intercepting structures surrounding the field borders, like artificial screens and natural hedges, which are not yet a part of the drift mitigation measures for field crop sprayers in Belgium. Drift-interception experiments were performed in a grassland (Lolium perenne) with various interception structures: Artificial screens with heights of 1, 1.5 and 2 m and screen open areas of 16, 36 and 63% and a row of Fagus sylvatica trees with a height of 1.5 m and an average leaf area index of 1.12 m2/m2. Experiments were performed according to the international standard ISO 22866. The interception structure was positioned at 1 m from the field border. From the results it was found that type of border structure as well as screen open area and screen height, have an important effect on the amount of spray drift. Highest drift reduction was found with a 1.5 m artificial screen with a 16% open area.

Evaporation drift of pesticides active ingredients.

Losses of pesticide active ingredients (a.i.) into the atmosphere can occur through several pathways. A main pathway is evaporation drift. The evaporation process of pesticide a.i., after application, is affected by three main factors: Physicochemical properties of the pesticide a.i., weather conditions and crop structure. The main physicochemical parameters are the Henry coefficient, which is a measure for the volatilization tendency of the pesticide a.i. from a dilute aqueous solution, and the vapour pressure, which is a measure for the volatilization tendency of the pesticide a.i. from the solid phase. Five pesticide a.i., with various Henry coefficients and various vapour pressures, were selected to conduct laboratory experiments: metalaxyl-m, dichlorovos, diazinon, Lindane and trifluralin. Evaporation experiments were conducted in a volatilization chamber. It was found that the evaporation tendencies significantly differed according to the physicochemical properties of the a.i.

Occurrence of spray drift for different crop types: cereal, cereal stubble and grassland.

Pesticide spray drift is affected by 4 main factors: weather conditions, spray application technique, physicochemical properties of the spray Liquid and surrounding characteristics. This research studied the importance of crop type being sprayed for drift occurrence. Drift experiments were performed over cereals, cereal stubbles and grassland according to the international standard ISO 22866. From the results it was found that drift occurrence in cereals and cereal stubbles was lower than drift occurrence in grassland. The differences between cereals and cereal stubbles were significant only at low wind speed.

Optimalisation and feasability of bioremediation systems for the processing of spray losses of pesticides.

Contamination of ground and surface water puts pressure on the use of pesticides. Pesticide contamination of water can often be linked to point sources rather than to diffuse sources. Examples of such point sources are areas on farms where pesticides are handled, filled into sprayers and where sprayers are cleaned. To reduce contamination from these point sources, different kinds of bio-remediation systems are in various member states of the EU. Bioremediation is the use of living organisms, primarily micro-organisms, to degrade the environmental contaminants into less toxic forms. In this study, the behaviour of six different pesticides with varying physico-chemical properties on substrates used in a bioremediation system is studied. The adsorption of individual pesticides on the substrates is determined. After determination of the adsorption coefficient Kd, it could be concluded for metalaxyl that coco chips had the highest sorption capacity, followed by straw, compost, willow chopping and a sandy loam soil.

Classification of spray nozzles based on droplet size distributions and wind tunnel tests.

Droplet size distribution of a pesticide spray is recognised as a main factor affecting spray drift. As a first approximation, nozzles can be classified based on their droplet size spectrum. However, the risk of drift for a given droplet size distribution is also a function of spray structure, droplet velocities and entrained air conditions. Wind tunnel tests to determine actual drift potentials of the different nozzles have been proposed as a method of adding an indication of the risk of spray drift to the existing classification based on droplet size distributions (Miller et al, 1995). In this research wind tunnel tests were performed in the wind tunnel of the International Centre for Eremology (I.C.E.), Ghent University, to determine the drift potential of different types and sizes of nozzles at various spray pressures. Flat Fan (F) nozzles Hardi ISO 110 02, 110 03, 110 04, 110 06; Low-Drift (LD) nozzles Hardi ISO 110 02, 110 03, 110 04 and Injet Air Inclusion (AI) nozzles Hardi ISO 110 02, 110 03, 110 04 were tested at a spray pressures of 2, 3 and 4 bar. The droplet size spectra of the F and the LD nozzles were measured with a Malvern Mastersizer at spray pressures 2 bar, 3 bar and 4 bar. The Malvern spectra were used to calculate the Volume Median Diameters (VMD) of the sprays.

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.

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.

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.

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.