Model for synoptic assessment of risk potential of chemical plant protection products

SYNOPS evaluates the risk potential for terrestrial (soil and field margins) and aquatic (surface water) organisms. It combines use data of pesticides with their application conditions and their inherent properties.

SYNOPS-GIS was developed to assess the environmental risk potential of plant protection strategies on landscape level using GIS functionalities by linking it to geo-referenced databases for land use, soil conditions and climate data and to a dataset of regionalised surveys of pesticide application. The GIS databases were established by integrating all environmental information on field level, which is necessary to estimate the environmental exposure by drift, run-off erosion and drainage.

Calculation of Exposure toxicity ratios (ETR= Predicted environmental concentration/Toxicity value of a.i.)

The risk indicator SYNOPS models pesticide fluxes via different pathways and the resulting concentrations in soil, surface waters and field margins and therefore provides a quantitative assessment of the environmental risk due to pesticides {Strassemeyer 2017}. Risks associated with plant protection products are assessed on field level by linking geospatial data of agricultural fields in in a considered region (InVeKOS), surface waters {AdV 2015}, topography {AdV 2008}, soil characteristics {BüK 2007}, and weather data {DWD 2016}, to a of pesticide use on the specific fields. Field-specific input data for SYNOPS includes the relevant biophysical soil parameters (e.g. organic carbon content, hydrological soil class, soil texture, and field capacity), average slope, daily weather (precipitation and temperature), field margin width, and connectivity to surface waters for all the all considered agricultural fields. Information on plant protection products (active substances, concentrations, labelled mitigation measures) are derived from the German product database, and physico-chemical properties of the active substances were obtained from the Pesticides Properties Database {Lewis2016}.

A short summary of the method described in Strassemeyer et al. {Strassemeyer2017} is presented here. Risk indices are expressed as the Exposure Toxicity Ratio (ETR), calculated as the ratio of the Predicted Environmental Concentration (PEC) to the toxicity endpoints half maximum effect concentration, lethal concentration, lethal rate, lethal dose, and no-effect concentration for specific reference species. The following reference species are considered: algae, aquatic invertebrates, fish, higher aquatic plants, and sediment organisms for aquatic environments; earthworm and springtails for soil; and honeybees, Aphidius rhopalosiphi, and Typhlodromus pyri for field edge habitats. Daily loads of the active substances to the three environmental compartments and a time-dependent curve of PEC were derived. Over a 365-day period, beginning with the first day of the growing season, the 90th percentile of the time-dependent PEC curves and the 90th percentile of the seven-day time-weighted average concentration are calculated to represent the worst-case scenario of acute and chronic exposure for each active substance. The acute toxicity endpoints multiplied with a factor of 0.1 and the no-effect concentration of each active substance were used to describe acute and chronic toxicity, respectively. In order to assess the mixture toxicity of the complete crop protection strategies with multiple fungicide applications and multiple active substances, the acute and chronic risk of the active substances were aggregated according to the principle of concentration addition {Zhan2012, Verro2009}. The risk values were added on a daily basis to derive ETR sum curves and the temporal 90th percentiles to represent the overall acute or chronic risk of a complete application calendars. The risk for the each compartment is calculated as maximum risk of the considered reference organisms.

Strassemeyer J, Daehmlow D, Dominic AR, Lorenz S and Golla B, SYNOPS-WEB, an online tool for environmental risk assessment to evaluate pesticide strategies on field level. Crop Prot 97:28–44 (2017).

Strassemeyer J and Golla B, Berechnung des Umweltrisikos der Pflanzenschutzmittelanwendungen in den Vergleichsbetrieben mittels SYNOPS. Gesunde Pflanz 70:10343-018 (2018).

AdV, Dokumentation zur Modellierung der Geoinformationen des amtlichen Vermessungswesens (GeoInfoDok): Erläuterungen zum ATKIS® Basis-DLM, Version 6.0.1, Stand 25.08.2015 (2015).

AdV, Dokumentation zur Modellierung der Geoinformationen des amtlichen Versuchswesens (GeoInfoDok): ATKIS-Objektartenkatalog Basis-DLM, Version 6.0, Stand 11.04.2008 (2008).

Verro R, Finizio A, Otto S and Vighi M, Predicting pesticide environmental risk in intensive agricultural areas. II: Screening level risk assessment of complex mixtures in surface waters. Environ Sci Technol 43:530–537 (2009).

Zhan Y and Zhang M, PURE: a web-based decision support system to evaluate pesticide environmental risk for sustainable pest management practices in California. Ecotoxicol Environ Saf 82:104–113 (2012).

• geospatial data of agricultural fields in in a considered region
• surface waters
• topography
• oil characteristics
• weather data
• pesticide use data
• Information on plant protection products (active substances, concentrations, labelled mitigation measures)
• physico-chemical properties of the active substances were obtained from the Pesticides Properties Database