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Het bepalen van afbraaksnelheden van gewasbeschermingsmiddelen in water onder realistische omstandigheden is belangrijk voor een correcte bepaling van blootstellingsconcentraties in de toelating. Om te beslissen of het zinvol is een software instrument te ontwikkelen om derden in staat te stellen hogere- trede, realistische afbraaksnelheden in water op een geautomatiseerde, relatief eenvoudige wijze af te leiden, heeft een inventarisatie plaatsgevonden. Ten eerste, om inzicht te verkrijgen in hoe vaak geschikte aquatische cosm studies in de buitenlucht beschikbaar zijn in registratie dossiers, en ten tweede, hoe vaak hogere-trede afbraaksnelheden gebruikt zijn in de toelatingsprocedure op EU, zonaal, of nationaal niveau. Voor 21 stoffen is informatie over aquatische cosm studies in de buitenlucht gevonden in de Europese stofbeoordelingsdossiers of nationale produktbeoordelingen. Voor 15 stoffen waren er voldoende metingen in water en sediment als functie van tijd en in gespecificeerde water- en sedimentlagen beschikbaar om een hogere-trede afbraaksnelheid te kunnen bepalen. Nadere beschouwing van de conclusie op de geaccordeerde Lijst van EindPunten van de Europese Autoriteit voor Voedselveiligheid, laat zien dat er voor geen van de 21 stoffen hogere-trede afbraaksnelheden in water zijn gebruikt op EU niveau. In de nationale, Nederlandse toelatingsprocedure voor gewasbeschermingsmiddelen zijn hogere-trede afbraaksnelheden gebruikt voor drie stoffen over de afgelopen 21 jaren. Hogere-trede afbraaksnelheden worden dus relatief weinig toegepast. Daar ontwikkeling en onderhoud van een software instrument om hogere-trede afbraaksnelheden geautomatiseerd te bepalen een substantiële inspanning vergt, bevelen wij niet aan om een dergelijk instrument nu te ontwikkelen. In het tweede deel van dit rapport wordt daarom een kort richtsnoer gegeven voor de schaarse gevallen dat het wel zinvol is een hogere-trede afbraaksnelheid in water af te leiden voor de toelatingsprocedure e

A new exposure assessment methodology for various tree crops and application methods was developed by Wageningen UR and PBL Netherlands Environmental Assessment Agency. In addition to the scenario for upward and sideways spraying in fruit orchards, which was published in 2021, this report describes the methodology for upward and sideways spraying in avenue tree nurseries and downward spraying in such nurseries and in fruit orchards. The new procedure calculates the exposure concentration based on a statistical distribution of the exposure concentration in all relevant Dutch watercourses. The methodology results in a so-called 90th percentile exposure concentration considering all watercourses alongside fruit orchards or avenue tree nurseries. The methodology accounts for the exposure by plant protection products through spray drift, drainage and atmospheric deposition. The scenarios include drift-reducing application techniques and crop-free buffer zones. With the scenarios in this report and the report on upward and sideways applications in fruit orchards, a more realistic exposure assessment is possible for edge-of-field watercourses next to fruit orchards and avenue tree nurseries regarding both upward & sideways applications and downward applications in the Netherlands., Dit rapport beschrijft een methodiek voor blootstellingsbeoordeling van waterorganismen in waterlopen na toepassing van gewasbeschermingsmiddelen in fruitboomgaarden en laanboomkwekerijen. Het is een combinatie van drie afzonderlijke onderzoeken naar blootstellingsbeoordeling, namelijk voor opwaartse en zijwaartse toepassingen in laanboomkwekerijen, neerwaartse toepassingen in deze kwekerijen en neerwaartse toepassingen in fruitboomgaarden.

The TOXSWA model has been extended with the functionality to simulate pesticide volatilization from open water surfaces on the basis of a micro-meteorological framework. TOXSWA simulates the fate of pesticides in water bodies to calculate exposure concentrations for aquatic organisms or sediment-dwelling organisms as part of the aquatic risk assessment in the regulatory process of pesticides at EU level and in The Netherlands. Volatilization of pesticides from water to air has been described in the TOXSWA model based on the Liss and Slater method. This report describes the implementation in TOXSWA of an improved methodology to describe volatilization of pesticides from small water bodies. Hourly meteorological data on wind speed and air temperature are used to calculate the rate of volatilization of the pesticide from the water layer., Het TOXSWA model beschrijft het gedrag van gewasbeschermingsmiddelen in het water-sediment systeem in kleine oppervlaktewateren. Het berekent hier blootstellingsconcentraties voor water- en sedimentorganismen, die in de aquatische toelatingsprocedure in Nederland en de EU worden gebruikt. Het model is nu verbeterd door de toevoeging van een functionaliteit voor vervluchtiging op basis van een micro- meteorologische benadering. De vervluchtiging wordt bepaald door het concentratie verschil op het atmosfeer-water grensvlak en hangt verder af van twee atmosferische weerstanden en een aquatische weerstand tegen transport van het gewasbeschermingsmiddel in de gasfase. De parameterisatie gebruikt uurlijkse waarden voor windsnelheid en temperatuur in water en in atmosfeer. Vervluchtiging van gewasbeschermingsmiddel is een belangrijk proces voor de blootstellingsconcentratieberekening. Vooral in stilstaand oppervlaktewater of water met lage stroomsnelheden kan de combinatie van langzame vervluchtiging, lage omzetting en herhaald toepassen leiden tot accumulatie van het middel in water en/of sediment en mogelijk verhoogde risico’s voor de organismen.

Estimation of the degradation rate of plant protection products in water under realistic conditions may be important for correct estimation of exposure concentrations for regulatory purposes. Standardized tests for degradation in water and in water-sediment systems in the laboratory exist, but these do not reflect degradation under field conditions. This is especially true for studies on photolytic degradation; therefore, generally photolytic degradation is not accounted for in the lower tiers of the exposure assessment. The aim of this study is to develop a procedure for the estimation of photochemical degradation rates from outdoor cosm experiments for use in the higher tiers of the exposure assessment. Observations in outdoor ponds or cosms are regularly used as a higher-tier risk assessment to evaluate the ecotoxicological effects on the aquatic ecosystem in a more realistic way. By means of inverse modelling of the behaviour of the compound in the cosm we determined the degradation rate in water, DegT50, for three compounds which are known to degrade photolytically. We did so by coupling the fate model TOXSWA to the optimisation tool PEST and determined the DegT50 for a daily reference UV radiation, weighed with a vitamin-D action spectrum, assuming that the degradation rate was directly proportional to the amount of weighed UV radiation. The UV radiation data were derived from satellite-based observations accounting for the effects of the thickness of the ozone layer and the cloud cover. For cosm studies with metribuzin, imidacloprid and metamitron we obtained satisfactory estimates of DegT50 values. After correcting these for effects of water depth, coverage of water surface by plants and the skyview factor on the UV radiation in the water, the variation between the DegT50 values of metribuzin and imidacloprid was smaller than the variation between DegT50 values derived (in an earlier study) by assuming that the degradation rate depended on water temperature, Het bepalen van afbraaksnelheden van gewasbeschermingsmiddelen in water onder realistische omstandigheden kan belangrijk zijn voor een correcte bepaling van blootstellingsconcentraties in de toelating. Er zijn standaard laboratorium testen voor afbraak in water en in water-sediment systemen, maar deze weerspiegelen niet de afbraak onder realistische omstandigheden in het veld. Dit geldt m.n. voor studies over fotochemische afbraak; dit is de reden dat fotochemische afbraak in het algemeen niet wordt meegenomen in de lagere treden van de blootstellingsbepaling. Het doel van deze studie is om een procedure te ontwikkelen voor de bepaling van fotochemische afbraaksnelheden met behulp van cosm experimenten in de buitenlucht, voor gebruik in de hogere treden van de blootstellingsbepaling. Waarnemingen in vijvers of cosms in de buitenlucht worden regelmatig gebruikt als hogere trede in de risicobeoordeling om ecotoxicologische effecten op het aquatisch ecosysteem op een realistischere manier te bepalen. Met behulp van een inverse modellering van het gedrag van een middel in de cosm hebben we de afbraaksnelheid in water, DegT50, bepaald voor drie middelen, waarvan het bekend is dat ze fotochemisch afbreken. Dit deden we door het model TOXSWA te koppelen aan het optimalisatie instrument PEST en de DegT50 te bepalen voor een dagelijkse referentie UV stralingsdosis, gewogen voor het vitamine D actiespectrum; hierbij werd aangenomen dat de afbraaksnelheid recht evenredig is met de gewogen UV straling. De UV stralingsdata waren afgeleid uit satelliet waarnemingen die rekening hielden met de dikte van de ozonlaag en de bewolkingsgraad. Voor de cosm studies met metribuzin, imidacloprid en metamitron verkregen we zo toereikend geschatte DegT50 waarden. Na een correctie voor de effecten van waterdiepte, bedekkingsgraad van het wateroppervlak door planten en de ‘hemelzicht’ factor op de UV straling in het water, was de variatie in DegT50 waarden van metribuzin en imidacloprid kleine

The European Commission asked EFSA to undertake a ‘repair action’ of the FOCUS surface water report after the EFSA Pesticide Steering Network had been consulted. The main request was to introduce into all FOCUS surface water scenarios (both run‐off and drainage) a 20‐year assessment period instead of the current 12‐ or 16‐month assessment period. Because of the 20‐year assessment period, the way application dates are defined needed to be reviewed, reconsidering the functionality of the pesticide application timing currently used. Guidance on how substance parameters should be handled when correlated with soil properties has been provided. Foliar wash‐off calculated in MACRO and Pesticide Root Zone Model was aligned and the appropriateness of including rotational crop aspects was discussed. Processing time and how to use the results of the exposure assessment were considered.

The FOCUS_TOXSWA model calculates exposure concentrations of pesticides and their metabolites in watercourses and ponds, of the so-called FOCUS surface water scenarios. These concentrations are used in the pesticide registration procedure at EU level. The model concepts of TOXSWA are described briefly. The procedure for using the TOXSWA kernel (i.e. expert use) and related input files and output files are described. Concerning FOCUS_TOXSWA, the use of the graphical user interface to access the input and output is described. Input data are stored in a database. Pesticide entries resulting from drainage or runoff/erosion are accessed from separate files generated by FOCUS_MACRO and FOCUS_PRZM. Substance properties are accessed from the SPIN tool/database. Instructions for simulating a water-sediment study and a multi-year run are given.

A methodology is presented to assess the exposure of aquatic organisms resulting from pesticide applications by sideways and upward spraying in Dutch fruit crops. It is the intention that this methodology will be used in Dutch pesticide registration. The methodology is based on the principle that the endpoint concentration represents a 90th percentile of the statistical population of concentrations to be expected in ditches alongside fruit crops. Furthermore the methodology is founded on the principle that the user should be able to choose between different drift-reduction technology (DRT) classes and between different widths of the crop-free buffer zone. Spray drift is the only exposure route considered in the methodology. The 90th percentile concentration (PEC90) is based on a spatially distributed model that simulates the frequency distribution of the annual maximum concentration of more than 70,000 spatial units (i.e. ditches characterised by waterbody properties and their orientation with respect to the direction of the rows of the fruit trees and to the N-E-S-W direction) for 100 simulation years. This frequency distribution was calculated for different application patterns, different DRT classes and different widths of the crop-free buffer zone. Next, one of the 70,000 spatial units was selected which fulfilled the criterion that it could be used to calculate this PEC90 for all combinations of application patterns, DRT classes and widths by selecting a suitable percentile of its temporal distribution of concentrations. The TOXSWA model (coupled to the hydrological SWQN model simulating water depths and water flow rates) was parameterised for this selected spatial unit to run for 26 years. The first six years were used as a ‘warming-up’ period and the remaining 20 years for assessing the required temporal percentile. The scenario ditch was 300 m long of which only the 100 m in the middle received a drift load of pesticide. The direction of water flow may chang, Dit rapport geeft een overzicht van een recent ontwikkelde methodiek voor blootstelling van waterorganismen in waterlopen na toepassing van gewasbeschermingsmiddeldn via zijwaarts en opwaarts spuiten in de Nederlandse fruitteelt.

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science to support the potential development of a risk assessment scheme of plant protection products for amphibians and reptiles. The coverage of the risk to amphibians and reptiles by current risk assessments for other vertebrate groups was investigated. Available test methods and exposure models were reviewed with regard to their applicability to amphibians and reptiles. Proposals were made for specific protection goals aiming to protect important ecosystem services and taking into consideration the regulatory framework and existing protection goals for other vertebrates. Uncertainties, knowledge gaps and research needs were highlighted.

The EFSA Panel on Plant Protection Products and their Residues reviewed the guidance on how aged sorption studies for pesticides should be conducted, analysed and used in regulatory assessment. The inclusion of aged sorption is a higher tier in the groundwater leaching assessment. The Panel based its review on a test with three substances taken from a data set provided by the European Crop Protection Association. Particular points of attention were the quality of the data provided, the proposed fitting procedure of aged sorption experiments and the proposed method for combining results obtained from aged sorption studies and lower‐tier studies on degradation and adsorption. Aged sorption was a relevant process in all cases studied. The test revealed that the guidance could generally be well applied and resulted in robust and plausible results. The Panel considers the guidance suitable for use in the groundwater leaching assessment after the recommendations in this Scientific Opinion have been implemented, with the exception of the use of field data to derive aged sorption parameters. The Panel noted that the draft guidance could only be used by experienced users because there is no software tool that fully supports the work flow in the guidance document. It is therefore recommended that a user‐friendly software tool be developed. Aged sorption lowered the predicted concentration in groundwater. However, because aged sorption experiments may be conducted in different soils than lower‐tier degradation and adsorption experiments, it cannot be guaranteed that the higher tier predicts lower concentrations than the lower tier, while lower tiers should be more conservative than higher tiers. To mitigate this problem, the Panel recommends using all available higher‐ and lower‐tier data in the leaching assessment. The Panel further recommends that aged sorption parameters for metabolites be derived only from metabolite‐dosed studies. The formation fraction can be derived fro

TOXSWA simuleert het gedrag van stoffen in oppervlaktewater om blootstellingsconcentratie te berekenen voor organismen die in water of sediment leven, als onderdeel van de aquatische risicobeoordeling van gewasbeschermingsmiddelen (GBM). Het vernieuwde concept voor de beschrijving van de temperatuur in het TOXSWA model werd getest aan de hand van een bestaande implementatie van het 1D bulk model.

Realistic values for the degradation rates of pesticides in surface water are important for thew aquatic risk assessment, that is mandatory before pesticides are admitted authorised. Standardised first-tier laboratory tests exist, but the degradation rates derived from these tests do not reflect the degradation rates in the environment. Outdoor ponds or cosms are often used as a higher-tier risk assessment to evaluate the ecotoxicological effects in a more realistic way.

The TOXSWA model has been extended with the functionality to simulate hydrolysis and biotic transformation in water. TOXSWA simulates the fate of pesticides in water bodies to calculate exposure calculations for aquatic organisms or sediment-dwelling organisms as part of the aquatic risk assessment of pesticides. Hydrolysis and biotic transformation are modelled as first-order processes, occuring in the water phase only. The hydrolysis transformation rates are considered to be dependent on both pH and temperature. The biotic transformation rate is considered to be temperature-dependent only.

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science behind the risk assessment of plant protection products for in-soil organisms. The current risk assessment scheme is reviewed, taking into account new regulatory frameworks and scientific developments. Proposals are made for specific protection goals for in-soil organisms being key drivers for relevant ecosystem services in agricultural landscapes such as nutrient cycling, soil structure, pest control and biodiversity. Considering the time-scales and biological processes related to the dispersal of the majority of in-soil organisms compared to terrestrial non-target arthropods living above soil, the Panel proposes that in-soil environmental risk assessments are made at in- and off-field scale considering field boundary levels. A new testing strategy which takes into account the relevant exposure routes for in-soil organisms and the potential direct and indirect effects is proposed. In order to address species recovery and long-term impacts of PPPs, the use of population models is also proposed.

In 2013, EFSA published a comprehensive systematic review of epidemiological studies published from 2006 to 2012 investigating the association between pesticide exposure and many health outcomes. Despite the considerable amount of epidemiological information available, the quality of much of this evidence was rather low and many limitations likely affect the results so firm conclusions cannot be drawn. Studies that do not meet the ‘recognised standards’ mentioned in the Regulation (EU) No 1107/2009 are thus not suited for risk assessment. In this Scientific Opinion, the EFSA Panel on Plant Protection Products and their residues (PPR Panel) was requested to assess the methodological limitations of pesticide epidemiology studies and found that poor exposure characterisation primarily defined the major limitation. Frequent use of case–control studies as opposed to prospective studies was considered another limitation. Inadequate definition or deficiencies in health outcomes need to be avoided and reporting of findings could be improved in some cases. The PPR Panel proposed recommendations on how to improve the quality and reliability of pesticide epidemiology studies to overcome these limitations and to facilitate an appropriate use for risk assessment. The Panel recommended the conduct of systematic reviews and meta‐analysis, where appropriate, of pesticide observational studies as useful methodology to understand the potential hazards of pesticides, exposure scenarios and methods for assessing exposure, exposure–response characterisation and risk characterisation. Finally, the PPR Panel proposed a methodological approach to integrate and weight multiple lines of evidence, including epidemiological data, for pesticide risk assessment. Biological plausibility can contribute to establishing causation.

In 2013, EFSA published a literature review on epidemiological studies linking exposure to pesticides and human health outcome. As a follow up, the EFSA Panel on Plant Protection Products and their residues (PPR Panel) was requested to investigate the plausible involvement of pesticide exposure as a risk factor for Parkinson's disease (PD) and childhood leukaemia (CHL). A systematic literature review on PD and CHL and mode of actions for pesticides was published by EFSA in 2016 and used as background documentation. The Panel used the Adverse Outcome Pathway (AOP) conceptual framework to define the biological plausibility in relation to epidemiological studies by means of identification of specific symptoms of the diseases as AO. The AOP combines multiple information and provides knowledge of biological pathways, highlights species differences and similarities, identifies research needs and supports regulatory decisions. In this context, the AOP approach could help in organising the available experimental knowledge to assess biological plausibility by describing the link between a molecular initiating event (MIE) and the AO through a series of biologically plausible and essential key events (KEs). As the AOP is chemically agnostic, tool chemical compounds were selected to empirically support the response and temporal concordance of the key event relationships (KERs). Three qualitative and one putative AOP were developed by the Panel using the results obtained. The Panel supports the use of the AOP framework to scientifically and transparently explore the biological plausibility of the association between pesticide exposure and human health outcomes, identify data gaps, define a tailored testing strategy and suggests an AOP's informed Integrated Approach for Testing and Assessment (IATA).