Toward a tiered regulatory framework for the prospective aquatic effect assessment of pesticides in (Neo)tropical areas

The Portuguese government (Foundation for Science and Technology [FCT]) is acknowledged for their support through the strategic project UIDB/04085/2020 (CENSE).Research and regulatory interest into (Neo)tropical aquatic pesticide ecotoxicology has increased considerably over the past few years. However, pesticide effect assessment frameworks in (Neo)tropical areas remain largely undeveloped and as such not implemented. The present study provides an overview of studies into the comparison of pesticide sensitivity between (Neo)tropical and temperate aquatic taxa. Recommended assessment factors to be applied to temperate toxicity data for use in tropical effect assessments differ significantly between these studies. Shortcomings and bottlenecks of available pesticide sensitivity comparison studies based on results from bioassays, species sensitivity distributions, and model ecosystem studies are scrutinized. Current data lacks and (subsequent) indications for future research are also covered. Ultimately, implications for procedures aimed at the derivation of regulatory acceptable concentrations for pesticides in (Neo)tropical edge-of-field surface waters are discussed. Integr Environ Assess Manag 2022;00:1–10. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).publishersversionepub_ahead_of_prin

Influence of climatic factors and microcosm complexity on the fate and effects of pesticides

Doutoramento em BiologiaApesar dos estudos de microcosmo e mesocosmo terem um papel importante no procedimento de registo dos pesticidas, a extensão pelos quais os resultados dos diferentes estudos de modelos de ecossistema poderem ser extrapolados para outros casos é ainda um assunto de debate. Esta tese pretende contribuir para a discussão sobre a influência local, temporal e dos factores metodológicos nos resultados dos estudos do microcosmo. Para este efeito, foram efectuados estudos do microcosmo com água doce em condições experimentais distintas e os efeitos do tratamento e o destino comparados com os reportados em experiências similares. As experiências com pequenos microcosmos laboratoriais com aplicações únicas de clorpirifos, linurão e carbendazim nem sempre previram as respostas exactas, tal como observado em experiências com modelos de ecossistema em larga escala. Uma vez que os sistemas utilizados eram fechados e não continham sedimento nem macrófitas, os pesticidas eram mais persistentes e os valores de toxicidade calculados tornaram-se mais comparáveis com os estabelecidos nas experiências com exposição prolongada. As implicações e as recomendações para a metodologia de estudos de avaliação de risco aquático são discutidos na secção discussão geral. Uma experiência do microcosmo na Tailândia, lidando com múltiplas aplicações de clorpirifos, conduziu à conclusão que o tempo de aplicação tem uma elevada influência nos efeitos do insecticida nas comunidades de água doce. Isto é explicado em relação às fases da população das comunidades de zooplâncton no momento da aplicação. Os valores de toxicidade calculados nos estudos do microcosmo tropical depois de aplicações únicas de pesticida estavam dentro da gama (clorpirifos e carbendazim) ou mais elevado (linurão) que os reportados em estudos temperados. Assim, estes resultados suportam o uso de dados de toxicidade de estudos de ecossistemas modelo levados a cabo em zonas temperadas para a avaliação de risco ambiental em países tropicais.Although micro- and mesocosm studies play an important role in the registration procedure of pesticides, the extent by which the results of different model ecosystem studies may be extrapolated to one another is still a matter of debate. This thesis aims to contribute to the discussion concerning the influence of spatial, temporal and methodological factors on the outcome of microcosm studies. For this purpose, freshwater microcosm studies were carried out under different experimental conditions and fate and treatment effects compared with those reported in similar experiments. Small indoor microcosm studies with single applications of chlorpyrifos, linuron and carbendazim did not always predict the exact responses as was observed in larger-scale model ecosystem studies. Since closed systems were used that did not contain sediment and macrophytes, pesticides were more persistent and calculated toxicity values were therefore generally more comparable with those reported in studies with long-term exposure. Implications and recommendations for the methodology of aquatic risk assessment studies are discussed in the general discussion section. A microcosm study in Thailand dealing with multiple chlorpyrifos applications led to the conclusion that the time of application has a large influence on the effects of the insecticide on freshwater communities. This is explained in relation to the population phase of zooplankton communities at the time of application. Threshold values calculated in tropical microcosm studies after single pesticide applications were well in range (chlorpyrifos and carbendazim) or higher (linuron) than those reported in temperate studies. These findings thus support the use of toxicity data from model ecosystem studies carried out in the temperate zone for the environmental risk assessment in tropical countries

Establishing causal links between aquatic biodiversity and ecosystem functioning: status and research needs

Understanding how changes in biodiversity affects ecosystem functioning is imperative in allowing Ecosystem-Based Management (EBM), especially when addressing global change and environmental degradation. Research into the link between biodiversity and ecosystem functioning (BEF) has indeed increased considerably over the past decades. BEF research has focussed on terrestrial ecosystems and aquatic ecosystems have received considerably less attention. Due to differences in phylogenetic diversity, ecological processes and reported BEF relationships, however, it may at least be questionable whether BEF relationships are exchangeable between these ecosystems (i.e. terrestrial and aquatic). The aim of the present paper was therefore to pinpoint key areas and bottlenecks in establishing BEF relationships for aquatic ecosystems (freshwater, transitional, and marine). To this end, the available literature with special emphasis on the last 10 years was assessed to evaluate: i) reported mechanisms and shapes of aquatic BEF relationships; ii) to what extent BEF relations are interchangeable or ecosystem-specific; and iii) contemporary gaps and needs in aquatic BEF research. Based on our analysis, it may be concluded that despite considerable progress in BEF research over the past decades, several bottlenecks still need to be tackled, namely incorporating the multitude of functions supported by ecosystems, functional distinctiveness of rare species, multitrophic interactions and spatial-temporal scales, before BEF relationships can be used in ecosystem-based management.publishe

The use of gene expression to unravel the single and mixture toxicity of abamectin and difenoconazole on survival and reproduction of the springtail Folsomia candida

Pesticides risk assessments have traditionally focused on the effects on standard parameters, such as mortality, reproduction and development. However, one of the first signs of adverse effects that occur in organisms exposed to stress conditions is an alteration in their genomic expression, which is specific to the type of stress, sensitive to very low contaminant concentrations and responsive in a few hours. The aim of the present study was to evaluate the single and binary mixture toxicity of commercial products of abamectin (Kraft® 36 EC) and difenoconazole (Score® 250 EC) to Folsomia candida. Laboratory toxicity tests were conducted to access the effects of these pesticides on springtail survival, reproduction and gene expression. The reproduction assays gave EC50 and EC10 values, respectively, of 6.3 and 1.4 mg a.s./kg dry soil for abamectin; 1.0 and 0.12 mg a.s./kg dry soil for Kraft® 36 EC; and 54 and 23 mg a.s./kg dry soil for Score® 250 EC. Technical difenoconazole did not have any effect at the concentrations tested. No significant differences in gene expression were found between the abamectin concentrations tested (EC10 and EC50) and the solvent control. Exposure to Kraft® 36 EC, however, significantly induced Cyp6 expression at the EC50 level, while VgR was significantly downregulated at both the EC10 and EC50. Exposure to the simple pesticide mixture of Kraft® 36 EC + Score® 250 EC caused significant up regulation of ABC transporter, and significant down regulation of VgR relative to the controls. GABA receptor also showed significant down-regulation between the EC10 and EC50 mixture treatments. Results of the present study demonstrate that pesticide-induced gene expression effects precede and occur at lower concentrations than organism-level responses. Integrating "omic" endpoints in traditional bioassays may thus be a promising way forward in pesticide toxicity evaluations

Impact of temperature on the toxicity of Kraft 36 EC® (a.s. abamectin) and Score 250 EC® (a.s. difenoconazole) to soil organisms under realistic environmental exposure scenarios

Pesticides can affect all receiving compartments, especially soils, and their fate and effects may be enhanced by temperature, increasing their risk to ecological functions of soils. In Brazil, the most widely used pesticides are the insecticide Kraft 36 EC® (a.s. abamectin) and the fungicide Score 250 EC® (a.s. difenoconazole), which are commonly used in strawberry, often simultaneously as a mixture. The aim of this study was to evaluate the toxicity of realistic environmental applications, single and in mixtures, for both pesticides to the springtail Folsomia candida and the plant species Allium cepa (onion) and Lycopersicum esculentum (tomato). Mesocosms filled with Brazilian natural soil (lattosolo) were dosed with water (control), Kraft (10.8 g a.s/ha), Score (20 g.a.s/ha) and Kraft + Score (10.8 + 20 g a.s./ha). The applications were repeated every 7 days, during 18 days of experiment, and simulating rainfall twice a week. Collembola reproduction tests were conducted with soils from the first (day 1) and last day (day 18) of experiment for each treatment. Plant toxicity tests were carried out in the experimental units. The experiments were run at 23 °C and 33 °C. Kraft, alone and in the binary mixture, showed high toxicity to the springtails in soils from both days 1 and 18, especially at 23 °C where it caused 100% mortality. Score however, was not toxic to the springtails. Plant growth was reduced by Score, but responses varied depending on temperature. This study indicates a high environmental risk of the insecticide Kraft, particularly at lower temperatures (23 °C), and an influence of temperature on pesticide fate and effects

Study of the Potential of Water Treatment Sludges in the Removal of Emerging Pollutants

This research was funded by CENSE through the Portuguese Foundation for Science and Technology (FCT; UIDB/04085/2020) and through a PhD grant for Rita Dias (SFRH/BD/148793/2019). The authors are also indebted to EPAL AdVT for their financial support to this project. This work was also supported by the Associate Laboratory for Green Chemistry-LAQV, which is financed by national funds from FCT/MCTES (UIDB/50006/2020). Maria Bernardo acknowledges Norma Transitoria DL57/2016 Contract (FCT/MCTES).Presently, water quantity and quality problems persist both in developed and developing countries, and concerns have been raised about the presence of emerging pollutants (EPs) in water. The circular economy provides ways of achieving sustainable resource management that can be implemented in the water sector, such as the reuse of drinking water treatment sludges (WTSs). This study evaluated the potential of WTS containing a high concentration of activated carbon for the removal of two EPs: the steroid hormones 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). To this end, WTSs from two Portuguese water treatment plants (WTPs) were characterised and tested for their hormone adsorbance potential. Both WTSs showed a promising adsorption potential for the two hormones studied due to their textural and chemical properties. For WTS1, the final concentration for both hormones was lower than the limit of quantification (LOQ). As for WTS2, the results for E2 removal were similar to WTS1, although for EE2, the removal efficiency was lower (around 50%). The overall results indicate that this method may lead to new ways of using this erstwhile residue as a possible adsorbent material for the removal of several EPs present in wastewaters or other matrixes, and as such contributing to the achievement of Sustainable Development Goals (SDG) targets.publishersversionpublishe

Invertebrate traits, diversity and the vulnerability of groundwater ecosystems

Funding Information: This manuscript evolved from a workshop titled Trait‐based analyses in groundwater ecology and bioassessment held as part of the 24th International Conference on Subterranean Biology, 20–24th August 2018, University of Aveiro, Portugal. The workshop was supported by the conference organisers and the Macquarie University Species Spectrum Research Centre. Financial support was also provided to M.A.D. by the Portuguese government (Fundação para a Ciência e Tecnologia; FCT) through the research unit UIDB/04085/2020 (CENSE). A.S.P.S.R. was supported by the VILLUM FONDEN (research grant 15471) and by Portuguese National Funds through Fundação para a Ciência e a Tecnologia within the cE3c Unit funding UIDB/00329/2020. S.I.S. acknowledges funding through EU Operational Programme Research, Development and Education No. CZ.02.2.69/0.0/0.0/16_027/0008357, and by the Ministry of Education, Youth and Sports of the Czech Republic [grant number CZ.02.1.01/0.0/0.0/16 025/0007417]. K.L.K. was supported in part by Australian Research Council grant LP190100927. The comments of the Editor, Associate Editor and an anonymous reviewer greatly improved the MS. Open access publishing facilitated by Macquarie University, as part of the Wiley ‐ Macquarie University agreement via the Council of Australian University Librarians. Publisher Copyright: © 2022 The Authors. Functional Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.Groundwater comprises the largest freshwater ecosystem on the planet. It has a distinct regime of extreme, yet stable environmental conditions that have favoured the development of similar morphological and functional traits in the resident invertebrate fauna (stygofauna). The analysis of community traits is increasingly used as an alternative to taxonomy-based assessments of biodiversity, especially for monitoring ecosystem status and linking the functions of organisms to ecological processes, yet it has been rarely applied to stygofauna and groundwater ecosystems. In this paper, we review the variation in functional traits among the invertebrate fauna of this important ecosystem. We focus on the stygofauna and processes of alluvium and fractured rock aquifers that are typified by small voids and fissures that constrain the habitats and environmental conditions. As a first step, we compare trait variability between groundwater and surface water invertebrate communities and then examine the significance of the ranges of these traits to the vulnerability of the ecosystem to change. Fifteen potentially useful functional traits are recognised. Eight of these have narrower ranges (i.e. exhibit fewer states, or attributes, of a particular trait) in groundwater than they do in surface water. Two traits have wider ranges. Our synthesis suggests that the relative stability of groundwater environments has led to low trait variability. The low biomass and low reproductive rate of stygofauna suggest that recovery potential following disturbance is likely to be low. For the purposes of both improved understanding and effective management, further work is needed to document additional functional traits and their states in groundwater fauna, enabling a better understanding of the relationship between response and effect traits in these ecosystems. Read the free Plain Language Summary for this article on the Journal blog.publishersversionpublishe

Impact of 2,4-D and fipronil on the tropical midge Chironomus sancticaroli (Diptera: Chironomidae)

The work was supported by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP, Brazil, grant no. 2015/18790-3). T.J.S.P., L.C.M.S., M.P.C.Y., and B.V.G. have a Ph.D. scholarship from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) and Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES). R.A.M. has a pos doctoral grant from FAPESP (2017/24126-4) and P.D.F has a scientific initiation grant (FAPESP 2019/04198-6). Financial support was also provided to M.A.D. by the Portuguese government (Fundacao para a Ciencia e Tecnologia; FCT) through the research unit UIDB/04085/2020 (CENSE).Increased use of pesticides in conventional agriculture implies potential risks to the environment. In aquatic ecosystems, benthic organisms may be exposed to pesticides via contaminated water and sediment, leading to several potential cascading effects on the food web. The aim of this study was to assess the functional implications of environmental realistic concentrations of the herbicide 2,4-D and the insecticide fipronil (alone and in combination) to the native tropical chironomid Chironomus sancticaroli. These two pesticides are widely applied to different crops and have frequently been detected (together) in surface water bodies in Brazil and elsewhere. Commercial products containing fipronil (Regent® 800WG) and 2,4-D (DMA® 806BR) were evaluated in 8-day toxicity tests for their effects on larval survival, growth (body length and biomass), head capsule width, development, and mentum deformities. Fipronil decreased the larval survival at the highest test concentration and the effective concentrations (EC) after eight days of exposure were: EC10 = 0.48 µg L−1 (0.395–0.565), EC20 = 1.06 µg L−1 (0.607–1.513), and EC50 = 3.70 µg L−1 (1.664–5.736). All sublethal test concentrations of fipronil decreased the larval growth, causing reductions in biomass up to 72%. The two highest test concentrations of fipronil decreased the head capsule width and after exposure to 3.7 µg fipronil L−1, only half of the larvae reached the fourth instar. The incidence of deformities was increased by fipronil in a concentration dependent manner with an increase ranging from 23% to 75%. The highest test concentration of 2.4-D (426 µg L−1) decreased the head capsule width, but larval development was unaffected at all concentrations evaluated. In the mixture tests, antagonism was observed at lower fipronil concentrations and synergism at higher fipronil concentrations for growth. The incidence of deformities rose with increasing fipronil concentrations. The results showed that environmental realistic concentrations of fipronil may have serious ecological implications for C. sancticaroli populations and that a mixture with the herbicide 2,4-D can have synergistic effects, potentiating the risks to the aquatic ecosystem.publishersversionpublishe

Is the Effect Assessment Approach for Fungicides as Laid Down in the European Food Safety Authority Aquatic Guidance Document Sufficiently Protective for Freshwater Ecosystems?

In Europe, the European Food Safety Authority aquatic guidance document describes the procedures for the derivation of regulatory acceptable concentrations (RACs) for pesticides in edge-of-field surface waters on the basis of tier-1 (standard test species), tier-2 (geometric mean and species sensitivity distributions [SSDs]), and tier-3 (model ecosystem studies) approaches. In the present study, the protectiveness of such a tiered approach was evaluated for fungicides. Acute and chronic RACs for tier-1 and tier-2B (SSDs) were calculated using toxicity data for standard and additional test species, respectively. Tier-3 RACs based on ecological thresholds (not considering recovery) could be derived for 18 fungicides. We show that tier-1 RACs, in the majority of cases, are more conservative than RACs calculated based on model ecosystem experiments. However, acute tier-2B RACs do not show a sufficient protection level compared with tier-3 RACs from cosm studies that tested a repeated pulsed exposure regime or when relatively persistent compounds were tested. Chronic tier-2B RACs showed a sufficient protection level, although they could only be evaluated for 6 compounds. Finally, we evaluated the suitability of the calculated RACs for 8 compounds with toxicity data for fungi. The comparison shows that the current RACs for individual fungicides, with a few exceptions (e.g., tebuconazole), show a sufficient protection level for structural and functional fungal endpoints. However, more data are needed to extend this comparison to other fungicides with different modes of action. Environ Toxicol Chem 2019:1–15.</p