Scientific Opinion addressing the state of the science on risk assessment of plant protection products for non-target terrestrial plants

Simulated herbicide drift alters native plant flowering phenology

Data for herbicide effects on plant flowering are needed to determine potential impacts on plant reproduction. Thus, flowering phenology was determined for up to 12 weeks after herbicide treatment for native Willamette Valley plants growing in small plots on two Oregon State University experimental farms. Six perennial species were evaluated: Camassia leichtlinii (CALE), Elymus glaucus (ELGL), Eriophyllum lanatum (ERLA), Festuca idahoensis subsp. roemeri (FEID), Iris tenax (IRTE), and Prunella vulgaris var. lanceolata (PRVU). Effects of glyphosate and dicamba, alone and in combination, were determined using simulated drift rates of 0.1 or 0.2 x field application rates (FAR) of 1119 g ha-1 active ingredient (a.i.) (830 g ha-1 acid glyphosate) for glyphosate and 560 g ha-1 a.i. for dicamba. Flowering phenology was evaluated as stage of development on a scale from no buds (converted to 0), buds (1), pre-flowering (2), flowering (3), post-flowering (4), to mature seeds (5) before herbicide treatment and for 12 weeks after treatment. Flowering response to herbicides varied by species and farm; but, in general, dicamba and glyphosate resulted in earlier flowering stages (delayed or not full flowering) for the dicot ERLA, and to a lesser extent, PRVU; and glyphosate resulted in earlier flowering stages for the monocot IRTE. Based on these data, the concentration of herbicide affecting flowering stage was 0.1 x FAR. Once flowering stage was inhibited by dicamba and glyphosate, plants generally did not recover to full flowering. This study provided evidence that common herbicides can affect flowering phenology of native plants with implications for seed production.

Regional diversity of the ALS gene and hormesis due to tribenuron-methyl in Centaurea cyanus L

Centaurea cyanus L. is a common field weed in Eastern Europe but only in Poland biotypes of this species with resistance to acetolactate synthase (ALS) inhibitors have been confirmed. This phenomenon is constantly developing and spreading to consecutive regions of Poland. This study aimed to assess the response of selected Polish C. cyanus populations to tribenuron-methyl and to analyse the genetic variability of the ALS gene of C. cyanus populations resistant to ALS inhibitors. Between 2017 and 2021, 13 seed samples were collected from eastern Poland and a dose-response study with tribenuron-methyl was performed. Eleven populations resistant to tribenuron-methyl were identified. All populations from this study as well as 6 additional resistant populations characterised in the previous dose-response studies were subjected to molecular analysis of the ALS gene. Target-site resistance due to mutations P197S, P197Q, P197T and P197A were identified in 8 populations from Warmia-Masuria and Podlaskie provinces. This is the first case of target-site resistance (TSR) in C. cyanus confirmed by sequencing of the ALS gene. Moreover in some resistant plants, ten changes in the amino acid ALS sequence were identified in comparison to those in the susceptible ones. In none of the populations were all mutations detected in the same individual. The highest frequency of mutations was detected in Warmia-Masuria province. Some C. cyanus populations resistant to ALS inhibitors showed hormesis effect concerning shoot fresh weight after tribenuron-methyl treatment. Stimulation due to half the recommended dose of tribenuron-methyl was the highest and the difference between untreated and treated plants was statistically significant in two populations from Warmia-Masuria and in one from Podlaskie province.

Reproducibility, reliability, and regulatory relevance of plant visual injury assessments

The registration of herbicides in the European Union requires an assessment of risks to nontarget terrestrial plants (NTTPs). Regulatory plant studies are performed to determine risk-assessment-relevant endpoints (50% effect rate) for quantitative parameters, mostly biomass and survival. Recently, the European Food Safety Authority stated that endpoints for qualitatively assessed plant visual injuries (PVIs) such as necrosis, chlorosis, and so forth should be considered for the risk assessment as equal to endpoints derived from quantitatively determined parameters. However, the lack of guidance in the NTTP test guidelines on how to assess PVI and how to derive a statistically meaningful endpoint for PVI makes their use in risk assessments challenging. To evaluate and improve the reliability, reproducibility, and regulatory relevance of PVI assessments in NTTP studies, the PVI Working Group was formed in 2022 within the SETAC Plant Interest Group. In a first exercise, research needs, guidance gaps, and shortcomings in current methodologies were identified and are presented together with recommendations for a future, validated, and harmonized method for the assessment of PVI. Survey results revealed a high variability in how PVI are currently assessed, and that the reliability of these data is unclear. Under current conditions, the PVI data can rather be seen as supportive information instead of using the data for the statistically sound determination of a regulatory endpoint. Consequently, standardization and harmonization of procedures for the assessment of PVI are needed. An improved scoring methodology should be developed that allows for a precise, statistically sound endpoint determination. Regarding the regulatory relevance of PVI, further research is required to assess the biological meaning of PVI data and how this is connected to the regulatory requirements and protection goals. Last but not least, guidance is required on how to evaluate the historically available PVI data that are based on various assessment methodologies. Integr Environ Assess Manag 2024;20:915-923. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Mixture Toxicity of Herbicides with Dissimilar Modes of Action to Myriophyllum spicatum

Considering the vital role of rooted macrophytes in the aquatic ecosystem, validating assumptions on the interactive effects of herbicides with different modes of action at an environmentally relevant mixture ratio is necessary. We investigated the effects of diflufenican (a carotenoid biosynthesis inhibitor) and iodosulfuron-methyl-sodium (IMS; an acetolactate synthase inhibitor) in a 14-day growth inhibition experiment with Myriophyllum spicatum, wherein single compounds and their combination were tested in parallel (n = 84). The assessment was done using three different methods: significance testing, model deviation ratio (MDR), and mixture interaction factor (MIF). Interactions relative to both concentration addition and independent action were assessed via significance testing. This revealed that diflufenican and IMS acted antagonistically relative to both models for fresh weight and total shoot length (p < 0.05) and that there was slight synergism for the number of side shoots (p < 0.001) relative to concentration addition. The MDR and MIF can only assess interactions relative to the concentration addition model. According to MDR, the mixture appeared to show no interaction (neither antagonistic nor synergistic), whereas the MIF method revealed that the compounds acted antagonistically for fresh weight and that there was a slight synergism for total shoot length and number of side shoots. We conclude that inferences about mixture toxicity interactions are method- and endpoint-dependent, which can have implications for regulatory mixtures assessment. Environ Toxicol Chem 2022;41:2209-2220. © 2022 SETAC.

Arbuscular Mycorrhizal Fungi and the Need for a Meaningful Regulatory Plant Protection Product Testing Strategy

Arbuscular mycorrhizal fungi (AMF) perform key soil ecosystem services and, because of their symbiotic relationship with plant roots, may be exposed to the plant protection products (PPPs) applied to soils and crops. In 2017, the European Food Safety Authority (EFSA) released a scientific opinion addressing the state of the science on risk assessment of PPPs for in-soil organisms, recommending the inclusion of AMF ecotoxicological testing in the PPP regulatory process. However, it is not clear how this can be implemented in a tiered, robust, and ecologically relevant manner. Through a critical review of current literature, we examine the recommendations made within the EFSA report and the methodologies available to integrate AMF into the PPP risk assessment and provide perspective and commentary on their agronomic and ecological relevance. We conclude that considerable research questions remain to be addressed prior to the inclusion of AMF into the in-soil organism risk assessment, many of which stem from the unique challenges associated with including an obligate symbiont within the PPP risk assessment. Finally, we highlight critical knowledge gaps and the further research required to enable development of relevant, reliable, and robust scientific tests alongside pragmatic and scientifically sound guidance to ensure that any future risk-assessment paradigm is adequately protective of the ecosystem services it aims to preserve. Environ Toxicol Chem 2022;41:1808-1823. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A critical review of effect modeling for ecological risk assessment of plant protection products

A wide diversity of plant protection products (PPP) is used for crop protection leading to the contamination of soil, water, and air, which can have ecotoxicological impacts on living organisms. It is inconceivable to study the effects of each compound on each species from each compartment, experimental studies being time consuming and cost prohibitive, and animal testing having to be avoided. Therefore, numerous models are developed to assess PPP ecotoxicological effects. Our objective was to provide an overview of the modeling approaches enabling the assessment of PPP effects (including biopesticides) on the biota. Six categories of models were inventoried: (Q)SAR, DR and TKTD, population, multi-species, landscape, and mixture models. They were developed for various species (terrestrial and aquatic vertebrates and invertebrates, primary producers, micro-organisms) belonging to diverse environmental compartments, to address different goals (e.g., species sensitivity or PPP bioaccumulation assessment, ecosystem services protection). Among them, mechanistic models are increasingly recognized by EFSA for PPP regulatory risk assessment but, to date, remain not considered in notified guidance documents. The strengths and limits of the reviewed models are discussed together with improvement avenues (multigenerational effects, multiple biotic and abiotic stressors). This review also underlines a lack of model testing by means of field data and of sensitivity and uncertainty analyses. Accurate and robust modeling of PPP effects and other stressors on living organisms, from their application in the field to their functional consequences on the ecosystems at different scales of time and space, would help going toward a more sustainable management of the environment. Graphical Abstract Combination of the keyword lists composing the first bibliographic query. Columns were joined together with the logical operator AND. All keyword lists are available in Supplementary Information at https://doi.org/10.5281/zenodo.5775038 (Larras et al. 2021).

Phytotoxic Effects of Antibiotics on Terrestrial Crop Plants and Wild Plants: A Systematic Review

This review examines the state of knowledge on the phytotoxic effects of antibiotics on terrestrial crop plants and wild (non-crop) plants with the goal of evaluating differences in their sensitivity. This is important because environmental risk assessments of antibiotics currently consider their potential effects only on crop species but not wild species. Overall, we analysed 275 datasets consisting of antibiotic-plant species-endpoint combinations for germination (mg/L) and 169 datasets for plant growth (elongation and biomass) (mg/kg). EC10 and EC50 of each parameter were compared using a quotient approach, in which the geometric mean and the 5th percentile of the crop data were divided by wild data. Quotients were > 1 for elongation growth, suggesting that wild species were more sensitive than crops, while they were < 1 for biomass growth, suggesting quite the contrary. However, < 1% of the data in each dataset came from wild species, preventing definitive conclusions. Merging crop and wild data to evaluate differences in sensitivity among classes of antibiotics and plant families, we found using a linear mixed effect model and post hoc test that plants were most sensitive to phenicol and least sensitive to macrolides and tetracyclines. Further work must be conducted to gain a better understanding of the phytotoxic effects of antibiotics on terrestrial wild plants and subsequently assess whether the current approach to environmental risk assessment of antibiotics is sufficient to protect plant biodiversity.

The use of ecological models to assess the effects of a plant protection product on ecosystem services provided by an orchard

The objective of this case study was to explore the feasibility of using ecological models for applying an ecosystem services-based approach to environmental risk assessment using currently available data and methodologies. For this we used a 5 step approach: 1) selection of environmental scenario, 2) ecosystem service selection, 3) development of logic chains, 4) selection and application of ecological models and 5) detailed ecosystem service assessment. The study system is a European apple orchard managed according to integrated pest management principles. An organophosphate insecticide was used as the case study chemical. Four ecosystem services are included in this case study: soil quality regulation, pest control, pollination and recreation. Logic chains were developed for each ecosystem service and describe the link between toxicant effects on service providing units and ecosystem services delivery. For the soil quality regulation ecosystem service, springtails and earthworms were the service providing units, for the pest control ecosystem service it was ladybirds, for the pollination ecosystem service it was honeybees and for the recreation ecosystem service it was the meadow brown butterfly. All the ecological models addressed the spatio-temporal magnitude of the direct effects of the insecticide on the service providing units and ecological production functions were used to extrapolate these outcomes to the delivery of ecosystem services. For all ecosystem services a decision on the acceptability of the modelled and extrapolated effects on the service providing units could be made using the protection goals as set by the European Food Safety Authority (EFSA). Developing quantitative ecological production functions for extrapolation of ecosystem services delivery from population endpoints remains one of the major challenges. We feel that the use of ecological models can greatly add to this development, although the further development of existing ecological models, and of new models, is needed for this.

Identifying ecological production functions for use in ecosystem services-based environmental risk assessment of chemicals

There is increasing research interest in the application of the ecosystem services (ES) concept in the environmental risk assessment of chemicals to support formulating and operationalising regulatory environmental protection goals and making environmental risk assessment more policy- and value-relevant. This requires connecting ecosystem structure and processes to ecosystem function and henceforth to provision of ecosystem goods and services and their economic valuation. Ecological production functions (EPFs) may help to quantify these connections in a transparent manner and to predict ES provision based on function-related descriptors for service providing species, communities, ecosystems or habitats. We review scientific literature for EPFs to evaluate availability across provisioning and regulation and maintenance services (CICES v5.1 classification). We found quantitative production functions for nearly all ES, often complemented with economic valuation of physical or monetary flows. We studied the service providing units in these EPFs to evaluate the potential for extrapolation of toxicity data for test species obtained from standardised testing to ES provision. A broad taxonomic representation of service providers was established, but quantitative models directly linking standard test species to ES provision were extremely scarce. A pragmatic way to deal with this data gap would be the use of proxies for related taxa and stepwise functional extrapolation to ES provision and valuation, which we conclude possible for most ES. We suggest that EPFs may be used in defining specific protection goals (SPGs), and illustrate, using pollination as an example, the availability of information for the ecological entity and attribute dimensions of SPGs. Twenty-five pollination EPFs were compiled from the literature for biological entities ranging from 'colony' to 'habitat', with 75% referring to 'functional group'. With about equal representation of the attributes 'function', 'abundance' and 'diversity', SPGs for pollination therefore would seem best substantiated by EPFs at the level of functional group.

Key considerations to inform operational EU-specific protection goals: An example for non-target terrestrial plants

This paper complements recent considerations of specific protection goals (SPG) to inform risk assessments for non-target terrestrial plants (NTTP) in the European Union. The SPG options in-field appear to be of the most disruptive potential from agronomic perspective and are therefore investigated in more detail. Overarching prerequisites have been identified that need to be accounted for to ensure that any of the potential SPG options remain operational in a sustainable agricultural context. As soon as crop production is considered a desired ecosystem service for the in-field, its specific requirements in the context of sustainable agriculture have to be factored in. Good agricultural practices (GAPs), potential ecosystem disservices (e.g. weeds, pests and diseases) and supporting and regulating services need to be considered to ensure a successful and sustainable delivery of the ecosystem service crop production. Concerning in-field SPG options for NTTP specifically GAPs related to integrated weed management (IWM) require detailed assessment, as they individually and in combination have the purpose of weed control. Therefore, they result in specific implications to the environment, ecosystem services and biodiversity within the context of sustainable agricultural production. When diverging in-field ecosystem services are considered for the same context, the protection goals options require an additional assessment of synergies and trade-offs between the relevant ecosystem services (e.g. crop production, climate regulation and aesthetic values), a corresponding weighing and prioritization. Similarly, for biodiversity conservation, the trade-offs and synergies between sustainable crop production and specific habitat requirements need to be accounted for. Consequently, an interdisciplinary approach can ensure that SPG are operational by integrating a broad understanding of cropping systems, the environmental impact of the tools a farmer uses and the link between habitat availability, the impact of any of the applied tools on habitat quality and the broader landscape context. Integr Environ Assess Manag 2021;17:905-910. © 2021 Bayer AG, BASF SE and Syngenta. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Application of Polypodiopsida Class in Nanotechnology-Potential towards Development of More Effective Bioactive Solutions

The area of phytosynthesized nanomaterials is rapidly developing, with numerous studies being published yearly. The use of plant extracts is an alternative method to reduce the toxic potential of the nanomaterials and the interest in obtaining phytosynthesized nanoparticles is usually directed towards accessible and common plant species, ferns not being explored to their real potential in this field. The developed nanoparticles could benefit from their superior antimicrobial and antioxidant properties (compared with the nanoparticles obtained by other routes), thus proposing an important alternative against health care-associated and drug-resistant infections, as well as in other types of applications. The present review aims to summarize the explored application of ferns in nanotechnology and related areas, as well as the current bottlenecks and future perspectives, as emerging from the literature data.

Effects of Low Doses of Herbicides on Different Endpoints in the Life Cycle of Nontarget Terrestrial Plants

Herbicide drift may cause adverse effects on natural and seminatural plant communities, and it has been debated whether the current ecological risk assessments are adequate to protect nontarget terrestrial plant species. In the present study, 9 nontarget terrestrial plant species with different lifespans (3 annual/6 perennial) belonging to 6 different plant families were exposed to 4 herbicides with different modes of action at the vegetative (6-8 leaf) and reproductive (bud) stages separately. The plant tests were conducted under controlled conditions in 2 greenhouses, 1 located in Denmark and 1 in Canada. For both growth stages, effects were recorded on vegetative (above-ground biomass 3 wk after treatment) and reproductive endpoints (number and germinability of seeds). In most cases, responses following exposure at the juvenile stage were greater than responses following exposure at the reproductive stage. For the combinations of herbicides and plant species included in the present study, we found that the sensitivities of vegetative and reproductive endpoints were equal, or else vegetative endpoints were more sensitive than reproductive endpoints. We also found that annual species were more sensitive than perennial species. The overall conclusions cover many different response patterns, and it is evident that some effects may not be found in the currently used standard tests. Generally, more pronounced effects were obtained in Denmark compared with Canada, highlighting the fact that even under standardized test conditions and following common guidelines, several uncontrollable factors can still induce variable results. Environ Toxicol Chem 2021;40:1389-1404. © 2021 SETAC.

Statement of the PPR Panel on a framework for conducting the environmental exposure and risk assessment for transition metals when used as active substances in plant protection products (PPP)

The European Commission asked the European Food Safety Authority (EFSA) to prepare a statement on a framework for the environmental risk assessment (ERA) of transition metals (e.g. iron and copper) used as active substances in plant protection products (PPPs). Non-degradability, essentiality and specific conditions affecting fate and behaviour as well as their toxicity are distinctive characteristics possibly not covered in current guidance for PPPs. The proposed risk assessment framework starts with a preliminary phase, in which monitoring data on transition metals in relevant environmental compartments are provided. They deliver the metal natural background and anthropogenic residue levels to be considered in the exposure calculations. A first assessment step is then performed assuming fully bioavailable residues. Should the first step fail, refined ERA can, in principle, consider bioavailability issues; however, non-equilibrium conditions need to be taken into account. Simple models that are fit for purpose should be employed in order to avoid unnecessary complexity. Exposure models and scenarios would need to be adapted to address environmental processes and parameters relevant to the fate and behaviour of transition metals in water, sediment and soils (e.g. speciation). All developments should follow current EFSA guidance documents. If refined approaches have been used in the risk assessment of PPPs containing metals, post-registration monitoring and controlled long-term studies should be conducted and assessed. Utilisation of the same transition metal in other PPPs or for other uses will lead to accumulation in environmental compartments acting as sinks. In general, it has to be considered that the prospective risk assessment of metal-containing PPPs can only cover a defined period as there are limitations in the long-term hazard assessment due to issues of non-degradability. It is therefore recommended to consider these aspects in any risk management decisions and to align the ERA with the goals of other overarching legislative frameworks.

A Field Study Method as a Potential Higher Tier Option to Refine Herbicide Risk Assessment for Nontarget Terrestrial Plants

During herbicide spray application, nontarget terrestrial plants (NTTPs) growing in the off-field area need to be protected from unacceptable effects of herbicide drift. The risk of such unintended effects is assessed in order to establish whether a particular use can be approved, possibly in combination with mitigation measures. In Europe, the risk of herbicide treatment to NTTPs is assessed on the basis of tier 2 studies done under controlled conditions in greenhouses. Following the concept of a tiered testing approach, higher tier field studies under more realistic conditions could be used to refine the risk assessment. No current guideline for conducting higher tier NTTP field studies is available. We developed an NTTP higher tier field study method done on an experimental plant community established by sowing of a seed mixture. The setup was optimized in 3 pilot field studies and subsequently used for a definitive study testing effects of the herbicide iofensulfuron-sodium. Results show that the method can be regarded as a suitable higher tier option for assessing effects of herbicides on NTTPs. Growth of species from the soil seed bank cannot be avoided and has to be carefully considered when evaluating results. Adaptations of the study design may be necessary when testing different herbicides. Community-level endpoints were at the same level as single-species endpoints. Results of the field study were compared to standard greenhouse study results for the same herbicide. No observed effect rates (NOERs) in the field were about a factor of 10 higher and show that the current tier 2 risk assessment for NTTPs can be regarded as protective in this case. Whether the present field study design and the assessed endpoints can be used in higher tier risk assessment of NTTPs depends on selection of the specific protection goal and requires further discussion. Integr Environ Assess Manag 2020;16:691-705. © 2020 Bayer AG. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Feasibility of assessing vegetative and generative endpoints of crop- and non- crop terrestrial plant species for non-target terrestrial plant (NTTP) regulatory testing under greenhouse conditions

Agriculture is the dominating land-use in the EU member states covering nearly half of the surface area. Using herbicides to reduce weed competition in agricultural areas can adversely affect Non-Target Terrestrial Plants (NTTP) growing in field margins. According to the EFSA Scientific Opinion on NTTPs an important protection goal is to maintain the biodiversity of plant species in agricultural areas. EFSA recommends to include also non-crop species mentioned in OECD guidelines (OECD 208 and 227) in the testing and to assess not only vegetative but also generative endpoints during the plant life-cycle such as flowering and seed production. The objectives of this study were to evaluate the feasibility of assessing generative endpoints of crop and non-crop species for NTTP regulatory testing under greenhouse conditions and to assess if generative endpoints are more sensitive than vegetative endpoints. The experimental design consisted of one control and four herbicide (Atlantis® WG) application rates, with 6 replicates each. The application rates of the test substance were the maximum field rate and 30%, 10% and 3% of the field rate. Biomass, plant height, flowering, seed production as well as seedling emergence of the F1 generation were assessed. The study shows a feasible approach to assess vegetative and generative endpoints of (non-) crops species under greenhouse conditions on the basis of the OECD guideline 227. The vegetative endpoints plant height and biomass were not more sensitive if assessed during the generative growth stage when compared to the vegetative growth stage of the plants. In contrast to that, the generative endpoint seed production was partly more sensitive in comparison to the vegetative endpoints biomass and plant height. For regulatory NTTP studies, 5 or more test substance rates at non-lethal levels should be tested so to allow the determination of ER10/50 values for vegetative and generative endpoints.

Comparative Assessment of Vegetative and Reproductive Terrestrial Plant Species Endpoints from Exposure to Herbicides and Potential Environmental Implications: A Review

To investigate whether vegetative endpoints are protective of reproductive endpoints in terrestrial plant risk assessments (RAs) for authorization of plant protection products (PPPs), we assessed differences in sensitivity to herbicides between these parameters. Published literature and unpublished proprietary data generated for the registration of PPPs were used to compile a database. If reproductive endpoints were systematically more sensitive than the vegetative endpoints on which regulatory decisions are presently based, a concern could be raised about the protectiveness of the current RA process. Vegetative and reproductive endpoints were assessed considering further potentially relevant parameters. Reproductive endpoints were compared with vegetative endpoints of juvenile plants or with those of mature plants. Direct comparison by substance-species combination proved to be most adequate and was used to calculate quotients by effect level. In addition, we assessed the spread between different effect levels, estimating by which factor the conservatism would increase if effect rate (ER)50 endpoints were replaced by ER25 or ER10 endpoints with otherwise unchanged test parameters. Reproductive endpoints were found to be similarly sensitive as vegetative endpoints derived in nontarget terrestrial plant (NTTP) studies conducted following Organisation for Economic Co-operation and Development (OECD) or US Office of Chemical Safety and Pollution Prevention (OCSPP) guidelines. A switch from vegetative to reproductive endpoints would therefore not significantly change the conservatism (less than a factor of 1.5), whereas the change from ER50 to ER10 would (by a factor of ~5 to 6). However, because ecotoxicological tests on terrestrial plants bear intrinsic high variability that prevents the reliable detection of effects at the 10% effect level, ER10 endpoints are not a reliable basis for RA. No particular family, genus, or species with clusters of distinctly insensitive vegetative and sensitive reproductive endpoints could be identified that would call for regular testing of reproductive endpoints. Also, from the data set available, no specific herbicidal modes of action could be singled out for acting particularly on reproductive endpoints. Integr Environ Assess Manag 2020;16:166-183. © 2019 SETAC.

Historical control data for the interpretation of ecotoxicity data: are we missing a trick?

Wildlife can be exposed to chemicals in the environment from various anthropogenic sources. Ecotoxicity studies, undertaken to address the risks from potential exposure to chemicals, vary in their design e.g. duration of exposure, effect types and endpoints measured. Ecotoxicity studies measure biological responses to test item exposure. Responses can be highly variable, with limited opportunity for control of extrinsic sources of variability. It is critical to distinguish between treatment-related effects and background 'normal variability' when interpreting results. Historical control data (HCD) can be a valuable tool in contextualising results from single studies against previous studies performed under similar conditions. This paper discusses the case for better use of HCD in ecotoxicology assessments, illustrating with case studies the value and difficulties of using HCD in interpretation of results of standard and higher-tier study designs. HCD are routinely used in mammalian toxicology for human health assessments, but not directly in ecotoxicology. The possible reasons for this are discussed e.g., different data types, the potential to mask effects, and the lack of guidance. These concerns are real but not insurmountable and we would like to see organisations such as OECD, EFSA and USEPA develop guidance on the principles of HCD collection. Hopefully, this would lead to greater use of HCD and regulatory acceptance. We believe this is not only a scientifically valid approach but also an ethical issue that is in line with societally driven legal mandates to minimise the use of vertebrate testing in chemical regulatory decision making.

Guidance on the assessment of the safety of feed additives for the environment

This guidance document is intended to assist the applicant in the preparation and the presentation of an application, as foreseen in Article 7.6 of Regulation (EC) No 1831/2003, for the authorisation of additives used in animal nutrition. It specifically covers the assessment of the safety for the environment. [Table: see text].

Comparative assessment of the intrinsic sensitivity of crop species and wild plant species to plant protection products and their active substances and potential implications for the risk assessment: A literature review

A comprehensive critical review was undertaken aiming to compare the intrinsic sensitivity of terrestrial plant species (crop species and noncrop wild species) with published literature and unpublished proprietary data generated for the registration of plant protection products (PPPs), and a database was compiled. Data were assessed to answer the question whether crops differ from noncrop plants in their intrinsic sensitivity to PPPs. Endpoints were assessed considering further potentially relevant parameters by means of different methods, including a quotient approach, in which overall crop endpoints were divided by matching wild species endpoints. Quotients above 1 indicated that wild species were more sensitive than crops, quotients below 1 the opposite. Further methods included a multiple regression analysis and different approaches to assess the statistical power. The overall finding was that there were no consistent differences in sensitivity between wild plant species and crop species, based on ER50, ER25, and ER10 vegetative endpoints (the largest fraction of data). This was also true when censored endpoints, seedling emergence data, and other measured variables such as shoot height were included. Statistically significant differences occurred in both directions and were balanced, that is, there was no clear trend for either crops or noncrop species to be more sensitive than the other. On the basis of multivariate regression analysis, crops were found to be significantly more sensitive than wild plant species, albeit by a small margin (factor ≈1.4). Minimum detectable difference (MDD) analysis and multivariate regression analysis of modified datasets indicated that when using a data set of this size and heterogeneity, any dissimilarity between crop and wild species was detectable if exceeding a factor of 1.4 in either direction. For the taxonomic groups assessed here (i.e., with data), no intrinsic difference in sensitivity to PPPs between crop species and wild plant species was found. Integr Environ Assess Manag 2019;15:176-189. © 2018 SETAC.

Limits of Concern: suggestions for the operationalisation of a concept to determine the relevance of adverse effects in the ERA of GMOs

BACKGROUND

The European Food Safety Authority proposed a concept for the environmental risk assessment of genetically modified plants in the EU that is based on the definition of thresholds for the acceptability of potential adverse effects on the environment. This concept, called Limits of Concern (LoC), needs to be further refined to be implemented in the environmental risk assessment of genetically modified organisms.

METHODS

We analyse and discuss how LoC can be defined for the environmental risk assessment for three different types of genetically modified plants. We outline protection goals relevant to the genetically modified plants in question and discuss existing concepts and suggestions for acceptability thresholds from the environmental risk assessment of different regulatory areas. We make specific recommendations for the setting and use of LoC for each type of genetically modified plant.

RESULTS

The LoC concept can be suitably applied for the environmental risk assessment of genetically modified organisms, if the different protection goals in agro-environments are specifically considered. Not only biodiversity protection goals but also agricultural protection goals need to be addressed. The different ecosystem services provided by weeds inside and outside agricultural fields have to be considered for genetically modified herbicide-tolerant crops. Exposure-based LoCs are suggested based on knowledge about dose-effect relationships between maize pollen and non-target Lepidoptera for insect-resistant maize. Due to the long-term nature of biological processes such as spread and establishment, LoCs for genetically modified oilseed rape should be defined for the presence of the genetically modified plant or its genetically modified traits in relevant protection goals.

CONCLUSIONS

When setting LoCs, the focus should be on protection goals which are possibly affected. Potential overlaps of the LoC concept with the ecosystem service concept have to be clarified to harmonise protection levels in the agro-environment for different stressors. If additional impacts on agro-biodiversity resulting from the cultivation of genetically modified plants are to be avoided, then high protection levels and low thresholds for acceptable effects (i.e. LoC) should be set.

Linking pesticide marketing authorisations with environmental impact assessments through realistic landscape risk assessment paradigms

Each year, the European Food Safety Authority, supported by a network of experts in the EU Member States, assesses and publishes the environmental risks of 30-40 pesticides active substances. The assessments support hundreds of national risk evaluations for marketing (re-)authorisations of Plant Protection Products. These prospective regulatory evaluations are based on worst-case scenarios in order to provide the high level of protection required by the EU legislations, and establishes the conditions for a correct use of the products including risk mitigations options. However, recent publications suggest that the desired high level of protection may not be achieved with the current risk assessment paradigm. The consideration of larger spatial scales and multiple stressors, including different pesticide uses, could improve the risk assessment process. A next step is the use of these larger spatial scales for evidence-based assessments, evaluating the overall impact of pesticide use on the European environment and biodiversity. Reaching this level would provide science-based support to the National Plans on sustainable use of pesticides and to the broader EU policies defined in the EU Environmental Action Programmes. Recent technological developments, as well as policy efforts, have solved two of the key issues blocking this progress in the past. Data availability and technical capacity for handling Big Data are no longer an unaffordable obstacle. The current proposal presents an alternative environmental risk assessment paradigm, integrating use patterns and pesticides properties with landscape ecotypes and eco-regions, covering the variability of the European agro-environmental conditions. The paradigm is suggested to be implemented in a spatially explicit conceptual model, using the ecosystem services approach and vulnerable key driver species to represent the service providing units. This approach would allow mapping the likelihood and magnitude of the impact of pesticide use on ecosystems functions, environmental resources, and biodiversity at the EU scale.

Variability in Nontarget Terrestrial Plant Studies Should Inform Endpoint Selection

Inherent variability in nontarget terrestrial plant (NTTP) testing of pesticides creates challenges for using and interpreting these data for risk assessment. Standardized NTTP testing protocols were initially designed to calculate the application rate causing a 25% effect (ER25, used in the United States) or a 50% effect (ER50, used in Europe) for various measures based on the observed dose-response. More recently, the requirement to generate a no-observed-effect rate (NOER), or, in the absence of an NOER, the rate causing a 5% effect (ER05), has raised questions about the inherent variability in, and statistical detectability of, these tests. Statistically significant differences observed between test and control groups may be a product of this inherent variability and may not represent biological relevance. Attempting to derive an ER05 and the associated risk-assessment conclusions drawn from these values can overestimate risk. To address these concerns, we evaluated historical data from approximately 100 seedling emergence and vegetative vigor guideline studies on pesticides to assess the variability of control results across studies for each plant species, examined potential causes for the variation in control results, and defined the minimum percent effect that can be reliably detected. The results indicate that with current test design and implementation, the ER05 cannot be reliably estimated. Integr Environ Assess Manag 2018;14:639-648. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Potential impact of effects on reproductive attributes induced by herbicides on a plant community

Current herbicide risk assessment guidelines for nontarget terrestrial plants require testing effects on young, vulnerable life stages (i.e., seedling emergence [and subsequent growth] and vegetative vigor [growth and dry wt]) but not directly on the reproduction of plants. However, the European Food Safety Authority (EFSA) has proposed that effects on reproduction might be considered when evaluating the potential effects on plants. We adapted the plant community model for grassland (IBC-grass) to give insight into the current debate on the sensitivity of reproductive versus vegetative endpoints in ecological risk assessment. In an extensive sensitivity analysis of this model, we compared plant attributes potentially affected by herbicides and the consequences for long-term plant population dynamics and plant diversity. This evaluation was implemented by reducing reproductive as well as vegetative endpoints by certain percentages (e.g., 10-90%) as a theoretical assumption. Plant mortality and seed sterility (i.e., inability of seeds to germinate) were the most sensitive attributes. Our results indicated that effects on seed production at off-field exposure rates must be very strong to have an impact on the risk assessment. Otherwise, effects on seed production are compensated for by the soil seed bank. The present study highlights the usefulness of community level modeling studies to support regulators in their decisions on the appropriate risk assessment endpoints and provides confidence in their assessments. Environ Toxicol Chem 2018;37:1707-1722. © 2018 SETAC.

Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles

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.

Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles

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.

Effects of spray drift of glyphosate on nontarget terrestrial plants-A critical review

Glyphosate is a widely used broad-spectrum postemergent herbicide used for weed control in both agricultural and nonagricultural settings. Spray drift of glyphosate can pose a risk to nontarget terrestrial plants and plant communities outside the intended area of application, but the lack of a well-established predicted-no-effect drift rate makes properly assessing such risk difficult. For this reason, a literature review and meta-analysis was carried out with the aim to determine the level of drift that is likely to cause harm to plants and to explore what spray-reducing targets would be sufficiently protective. No-observed-adverse effect rates, lowest-observed-adverse effect rates, and effect rates giving 10, 25, and 50% effects were extracted from a total of 39 different publications. The data were combined per species, and species sensitivity distributions were constructed and fitted with a log-logistic model to assess protectiveness. No systematic differences were detected between the responses of monocotyledons or dicotyledons, but wild plants were found to be generally less sensitive to glyphosate drift than domesticated plants. The results indicate that restricting spray drift to a level below 5 g a.e./ha would protect approximately 95% of all higher plant species against minor adverse effects of glyphosate drift and that rates below 1 to 2 g a.e./ha would be almost completely protective. No studies were encountered that evaluated effects of spray drift against nonvascular plants, and therefore, the conclusions are only valid for vascular plants. Environ Toxicol Chem 2017;36:2879-2886. © 2017 SETAC.

Combined ecotoxicological risk assessment in the frame of European authorization of pesticides

Organisms are frequently exposed to mixtures of chemical contaminants in the environment, causing a potential "cocktail effect", or combined effect. The joint action of different molecules with similar or different modes of action could result in a potentially unlimited number of additives, synergistic or antagonistic combinations. Since the large number of contaminants makes it impossible to perform ecotoxicity tests for each potential mixture, a robust approach for prospective environmental risk assessment of chemical mixtures is needed. A number of recent publications by the European Commission and the authorities in charge prove the increasing interest that is spreading in the European community towards the topic of the assessment of chemical mixtures. The current EU regulation for Plant Protection Products authorization (Reg. 1107/2009 EC) explicitly requires the evaluation of the potential combined effects of active substances. We reviewed current methods and limitations of mixture assessment of pesticides (7 fungicides and 4 herbicides) through the analysis of the approaches adopted to investigate possible risks for different non-target organisms. The Concentration Addition (CA) approach was the most used approach to predict multiple toxicity to non-target organisms. The guidance for birds and mammals first introduced standard procedures to assess the multiple toxicity based on on CA concept. The recent aquatic EFSA guidance introduced some requirements to evaluate potential mixture toxicity, while the current guidance requirements for terrestrial organisms still lack clear indications on how to conduct the assessment. Moreover, new indications come from the draft guidance for the assessment of terrestrial plants and in-soil organisms. However, the approval and implementation of these new guidelines are still at a developmental stage. Some final considerations are drawn on the future possibilities to improve risk assessment procedures so as to identify harmful effects of pesticides mixtures on non-target organisms.

Scientific Opinion addressing the state of the science on risk assessment of plant protection products for in-soil organisms

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.

Food production, ecosystem services and biodiversity: We can't have it all everywhere

Debate about how sustainable intensification and multifunctionality might be implemented continues, but there remains little understanding as to what extent they are achievable in arable landscapes. Policies that influence agronomic decisions are rarely made with an appreciation of the trade-offs that exist between food production, biodiversity conservation and ecosystem service provision. We present an approach that can reveal such trade-offs when used to assess current and future policy options that affect agricultural inputs (e.g. pesticides, nutrients) and practices. In addition, by demonstrating it in a pesticide policy context, we show how safeguarding a range of ecosystem services may have serious implications for UK food security. We suggest that policy change is most usefully implemented at a landscape scale to promote multifunctionality, tailoring pesticide risk assessment and incentives for management that support bundles of ecosystem services to specific landscape contexts. In some instances tough trade-offs may need to be accepted. However, our approach can ensure that current knowledge is used to inform policy decisions for progress towards a more balanced food production system.

Recovery of terrestrial plants in vegetative vigor and seedling emergence tests from exposure to atrazine

Ten species of terrestrial plants, including 6 dicotyledonous and 4 monocotyledonous species, were exposed to a direct overspray of atrazine according to US Environmental Protection Agency seedling emergence and vegetative vigor study guidelines and subsequently evaluated for potential recovery. For each species, no-observed-effect rate (NOER), 10% effect rate, 25% effect rate, and 50% effect rate values were calculated (where possible) for a variety of guideline-required endpoints (but focusing on growth rate) for both the standard experimental phase and a recovery phase; and the rates subsequently were compared. For the seedling emergence study, the standard experimental (designated test 1) and recovery (designated test 2) phases encompassed days 0 to 14 and days 14 to 28, respectively. Similarly, for the vegetative vigor study, test 1 and test 2 encompassed days 0 to 21 and days 21 to 42, respectively. Plants were exposed to atrazine at nominal application rates ranging from 1.1 g active ingredient (a.i.)/ha (0.0010 lb a.i./A) to 28,000 g a.i./ha (25 lb a.i./A), depending on the species; the 28,000 g a.i./ha rate is greater than 12 times the maximum application rate of 2250 g a.i./ha (2 lb a.i./A) registered on corn. For seedling emergence, only 2 of 10 species tested, cabbage and tomato, provided clear rate responses in the initial 14 d of exposure (test 1). Based on a comparison of x% effect rate (ERx) and NOER values for growth rates of shoot length and shoot dry weight for days 0 to 14 relative to days 14 to 28, recovery was apparent for cabbage shoot length growth rate and tomato shoot length and shoot dry weight growth rates. Test application rates selected for the remaining 8 species showed either a weak response that did not allow a clear assessment of recovery or no response at all. For the vegetative vigor study, 9 of the 10 species tested provided clear rate responses in test 1 (days 0-21); corn did not demonstrate any herbicidal response up to the highest rate tested, 28,000 g a.i./ha. Based on comparison of day 0 to 21 (test 1) relative to day 21 to 42 (test 2) ERx and NOER values for shoot length, average growth rates indicated that 8 of 9 species clearly demonstrated an increase in 2 or more metrics (cabbage did not demonstrate a response based on shoot length). Clear recovery was also indicated by an increase in ERx and/or NOER values from test 1 to test 2 for shoot dry weight average growth rates for 7 of the 9 species (corn did not show a response, and oat and soybean showed variable responses). Thus, in most species, where initial herbicidal effects were observed, the effects are largely ameliorated over time.

Herbicide impact on the growth and reproduction of characteristic and rare arable weeds of winter cereal fields

The decline of arable species characteristic of winter cereal fields has often been attributed to different factors related to agricultural intensification but most importantly to herbicide use. Herbicide phytotoxicity is most frequently assessed using short-term endpoints, primarily aboveground biomass. However, short-term sensitivity is usually not sufficient to detect actual effects because plants may or may not recover over time following sublethal herbicide exposures. Therefore, it is important to assess the long-term effects of herbicide applications. Annual species rely on renewable seed production to ensure their persistence; hence, assessment of herbicide sensitivity is more accurately estimated through effects on reproduction. Here we aim to assess the phytotoxicity of two commonly used herbicides: tribenuron and 2,4-D on eight plant species belonging to four families, each with one rare and one more common species. Specifically we examined the pattern of sensitivity using short-term and long-term endpoints (total aboveground biomass, total seed biomass and number of seeds) of these species; we determined the levels of and time to recovery in terms of stem length and fruit number, and assessed whether their rarity relates to their sensitivity to herbicide application. Our results suggest that although differences in herbicide sensitivity are not a direct cause of rarity for all species, it may be an important driver of declining arable plants.

An ecosystem services approach to pesticide risk assessment and risk management of non-target terrestrial plants: recommendations from a SETAC Europe workshop

The registration of plant protection products (PPPs) in the EU is under Regulation 1107/2009, which recommends a tiered approach to assessing the risk to non-target terrestrial plants (NTTPs). However, little information is provided on how to perform and implement higher tier studies or how to use them to refine the risk assessments. Therefore, a stakeholder workshop was organized to consolidate current knowledge and expertise to aid the further development of testing and assessment procedures for NTTPs. This brief communication highlights the agreed recommendations of the workshop, which relate to the three main themes, i.e. specific protection goals, risk assessment and mitigation. The participants of the workshop adopted the European Food Safety Authority (EFSA) approach of using an ecosystem services framework for identifying specific protection goals. First, delivery and protection of ecosystem services were discussed for in-crop, in-field and off-crop, and off-field areas. Second, lower and higher tier risk assessment methods, including modelling approaches, were evaluated. Third, options for risk mitigation of spray drift and run-off were discussed and evaluated. Several important knowledge gaps were identified, and specific data collation and literature-based tasks were actioned to begin to address them. A full workshop report is planned for the fall of 2014.