Oppervlakkige afspoeling van gewasbeschermingsmiddelen: achtergronddocumentatie bij de tool IMAP : KIWK 2022-34

In dit rapport wordt beschreven welke beschikbare kennis en bestaande gegevensbestanden zijn gecombineerd in een tool voor telers en adviseurs. De inzichten in dit rapport vormen de basis voor de tool IMAP die de teler ondersteunt bij het maken van een afweging tussen maatregelen om afstroming van water en emissie van gewasbeschermingsmiddelen via oppervlakkige afspoeling vanaf hun percelen te verminderen. IMAP staat voor ‘Inzicht in Maatregelen tegen Afspoeling van middelen vanaf Percelen’

Testing the Greenhouse Emission Model (GEM) for Pesticides Applied via Drip Irrigation to Stone Wool Mats Growing Sweet Pepper in a Recirculation System

Pesticide emissions to surface water from greenhouses with crops grown on substrates in open or closed systems may be significant. It is important, therefore, to test models such as the Greenhouse Emission Model (GEM), which was developed to assess these emissions as part of the Dutch authorization procedure for use of plant protection products in greenhouses. GEM was tested using an experiment in which imidacloprid and pymetrozine were applied via drip irrigation to stone wool mats growing sweet pepper. The irrigation system in such greenhouses consists of a mixing tank to prepare the nutrient solution and a series of tanks to treat and recirculate the drain water back to the mixing tank. Emissions may occur because (part of) this recirculation water may be discharged or leached to the surface water. GEM assumes that all tanks are perfectly mixed. GEM further assumes that the water in these mats is perfectly mixed and that the pesticide behavior can be simulated by assuming one perfectly mixed reservoir. The model predicted breakthrough of both pesticides out of the mats earlier than measured, and the measured maximum concentrations were approximately two times lower than predicted. We considered a series of possible causes, including a smaller water volume in the mats, a higher plant uptake factor, and sorption to the stone wool. The model performance improved by representing the mats as a sequence of two equally large tanks with plant uptake restricted to the first tank. We recommend to study the solute transport process and the distribution of plant roots in the mats in more detail to further underpin the hypothesis used and improve the model. After this first validation, the GEM model might also be used in other countries to forecast emissions of PPPs to surface water

Development of surface water exposure scenarios for risk assessment of pesticides in Korea

Surface water exposure scenarios used in the risk assessment of Korea's aquatic ecosystems, were developed to represent the 90th percentile pesticide exposure situation as a part of the country's pesticide registration procedure. The scenarios are used to estimate the pesticide concentration in the water of a rice paddy and small streams for three protection goals: (i) mudfish in rice paddies, (ii) the aquatic ecosystem of small streams located near rice paddies, and (iii) the aquatic ecosystem of small streams located near fruit orchards. The scenarios were derived taking into account major exposure routes, such as spray drift, runoff, and drainage. The scenarios were parameterized for appropriate models including the pesticide root zone model (PRZM) and the toxic substances in surface waters model (TOXSWA). A total of 17 pesticide compounds and 28 formulated products were selected to test the risk assessment using the developed scenarios. The simulated predicted environmental concentrations (PECs) fully reflected a) the exposure routes for each protection goal b) the use patterns of the products c) physicochemical properties of the pesticides, and d) meteorological conditions of Korea. However, while assessing the risks for aquatic organisms we observed that for most of the selected pesticides the calculated exposure concentrations were higher than the regulatory acceptable concentration (RAC). To implement the exposure scenarios and models for pesticide authorization in Korea, further research on the RACs is needed. We also recommend studies to develop a higher-tier model and risk-mitigation measures that can be applied to the Korean situation.</p

Greenhouse data experiment drip irrigation 2016

The 'Greenhouse data experiment drip irrigation 2016' file contains data gathered during the experiment as described in Wipfler et al. (2020), Testing of the Greenhouse Emission Model for application of plant protection products via drip irrigation. WENR report 3004. Climate parameters were collected from the Lets Grow database, these parameters include water supply, drain water flow, external rainwater intake, radiation outside (W/m2), realized temperature and relative humidity in greenhouse compartment

Aquatic Risks at the Landscape Scale: A Case Study for Pyrethroid Use in Pome Fruit Orchards in Belgium

Procedures for environmental risk assessment for pesticides are under continuous development and subject to debate, especially at higher tier levels. Spatiotemporal dynamics of both pesticide exposure and effects at the landscape scale are largely ignored, which is a major flaw of the current risk assessment system. Furthermore, concrete guidance on risk assessment at landscape scales in the regulatory context is lacking. In this regard, we present an integrated modular simulation model system that includes spatiotemporally explicit simulation of pesticide application, fate, and effects on aquatic organisms. As a case study, the landscape model was applied to the Rummen, a river catchment in Belgium with a high density of pome fruit orchards. The application of a pyrethroid to pome fruit and the corresponding drift deposition on surface water and fate dynamics were simulated. Risk to aquatic organisms was quantified using a toxicokinetic/toxicodynamic model for individual survival at different levels of spatial aggregation, ranging from the catchment scale to individual stream segments. Although the derivation of landscape-scale risk assessment end points from model outputs is straightforward, a dialogue within the community, building on concrete examples as provided by this case study, is urgently needed in order to decide on the appropriate end points and on the definition of representative landscape scenarios for use in risk assessment

Greenhouse data experiment drip irrigation 2016

The 'Greenhouse data experiment drip irrigation 2016' file contains data gathered during the experiment as described in Wipfler et al. (2020), Testing of the Greenhouse Emission Model for application of plant protection products via drip irrigation. WENR report 3004. Climate parameters were collected from the Lets Grow database, these parameters include water supply, drain water flow, external rainwater intake, radiation outside (W/m2), realized temperature and relative humidity in greenhouse compartment