Risk from pesticide mixtures – The gap between risk assessment and reality

Weisner, Oliver; Frische, Tobias; Liebmann, Liana; Reemtsma, Thorsten; Roß-Nickoll, Martina; Schäfer, Ralf B.; Schäffer, Andreas; Scholz-Starke, Björn; Vormeier, Philipp; Knillmann, Saskia; Liess, Matthias

doi:10.1016/j.scitotenv.2021.149017

Cited by 57 publications

(25 citation statements)

References 50 publications

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“…The CUPs quantified in our work can have toxic effects, as known from the literature and investigated in marketing authorization. However, it is hard to interpret hair concentrations with regards to toxicity benchmarks because (1) relationships between residues in hairs of wild small mammals and exposure doses are not fully characterized, (2) time sequence in exposure are unknown, and (3) toxicity thresholds have been established usually under single compound exposure 79 , an assumption that is not fulfilled here. The present results provide valuable information from a global environmental contamination perspective since they allow identifying, at least partly, the mixtures of compounds that may be of concern for transfer in food webs and ecotoxicological impacts in wildlife.…”

Section: Discussionmentioning

confidence: 99%

Pervasive exposure of wild small mammals to legacy and currently used pesticide mixtures in arable landscapes

Fritsch

Appenzeller

Burkart

et al. 2022

Sci Rep

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Knowledge gaps regarding the potential role of pesticides in the loss of agricultural biodiversity worldwide and mixture-related issues hamper proper risk assessment of unintentional impacts of pesticides, rendering essential the monitoring of wildlife exposure to these compounds. Free-ranging mammal exposure to legacy (Banned and Restricted: BRPs) and currently used (CUPs) pesticides was investigated, testing the hypotheses of: (1) a background bioaccumulation for BRPs whereas a “hot-spot” pattern for CUPs, (2) different contamination profiles between carnivores and granivores/omnivores, and (3) the role of non-treated areas as refuges towards exposure to CUPs. Apodemus mice (omnivore) and Crocidura shrews (insectivore) were sampled over two French agricultural landscapes (n = 93). The concentrations of 140 parent chemicals and metabolites were screened in hair samples. A total of 112 compounds were detected, showing small mammal exposure to fungicides, herbicides and insecticides with 32 to 65 residues detected per individual (13–26 BRPs and 18–41 CUPs). Detection frequencies exceeded 75% of individuals for 13 BRPs and 25 CUPs. Concentrations above 10 ng/g were quantified for 7 BRPs and 29 CUPs (in 46% and 72% of individuals, respectively), and above 100 ng/g for 10 CUPs (in 22% of individuals). Contamination (number of compounds or concentrations) was overall higher in shrews than rodents and higher in animals captured in hedgerows and cereal crops than in grasslands, but did not differ significantly between conventional and organic farming. A general, ubiquitous contamination by legacy and current pesticides was shown, raising issues about exposure pathways and impacts on ecosystems. We propose a concept referred to as “biowidening”, depicting an increase of compound diversity at higher trophic levels. This work suggests that wildlife exposure to pesticide mixtures is a rule rather than an exception, highlighting the need for consideration of the exposome concept and questioning appropriateness of current risk assessment and mitigation processes.

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Section: Discussionmentioning

confidence: 99%

Pervasive exposure of wild small mammals to legacy and currently used pesticide mixtures in arable landscapes

Fritsch

Appenzeller

Burkart

et al. 2022

Sci Rep

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“…Effects of neonicotinoid mixtures on stream ecosystems are poorly understood because of regulatory and laboratory testing limitations. Pesticide testing, registration, use, and regulation target individual active compounds ( 18 , 19 ), whereas environmental exposures are predominantly to pesticide mixtures ( 19 , 20 ). As a result, nonadditive mixture risks [i.e., other than concentration addition (CA)] are not well documented ( 19 , 20 ).…”

Section: Introductionmentioning

confidence: 99%

“…Pesticide testing, registration, use, and regulation target individual active compounds ( 18 , 19 ), whereas environmental exposures are predominantly to pesticide mixtures ( 19 , 20 ). As a result, nonadditive mixture risks [i.e., other than concentration addition (CA)] are not well documented ( 19 , 20 ). Further, because single-species toxicity tests are the regulatory standard, toxicity databases are dominated by readily available laboratory-cultured taxa that may not be representative of the full range of sensitivities observed in endemic ecological communities.…”

Section: Introductionmentioning

confidence: 99%

Ecological consequences of neonicotinoid mixtures in streams

et al. 2022

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Neonicotinoid mixtures are common in streams worldwide, but corresponding ecological responses are poorly understood. We combined experimental and observational studies to narrow this knowledge gap. The mesocosm experiment determined that concentrations of the neonicotinoids imidacloprid and clothianidin (range of exposures, 0 to 11.9 μg/liter) above the hazard concentration for 5% of species (0.017 and 0.010 μg/liter, respectively) caused a loss in taxa abundance and richness, disrupted adult emergence, and altered trophodynamics, while mixtures of the two neonicotinoids caused dose-dependent synergistic effects. In 85 Coastal California streams, neonicotinoids were commonly detected [59% of samples ( n = 340), 72% of streams], frequently occurred as mixtures (56% of streams), and potential toxicity was dominated by imidacloprid (maximum = 1.92 μg/liter) and clothianidin (maximum = 2.51 μg/liter). Ecological responses in the field were consistent with the synergistic effects observed in the mesocosm experiment, indicating that neonicotinoid mixtures pose greater than expected risks to stream health.

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“…Albeit, in future pesticides will be extensively used as they will continue to play a vital role in the food production process and food security (Popp et al, 2013). Despite thorough regulation of pesticides, large knowledge gaps continue to hinder risk assessment, especially when it comes to potential environmental impact of pesticide mixtures and impacts of climate and regional factors (Weisner et al, 2021, Topping et al, 2020). In Northern Europe, an predicted increase in plant diseases and insect pests may consequently lead to higher pesticide use and thereby occurring concentration of pesticides in the environment (Kattwinkel et al, 2011, Delcour et al, 2015, Sutherst et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Probabilistic risk assessment of pesticides under future agricultural and climate scenarios using a Bayesian network

Mentzel

Grung

Holten

et al. 2022

Preprint

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The use of Bayesian networks (BN) for environmental risk assessment has increased in recent years. One reason is that they offer a more transparent way to characterize risk and evaluate uncertainty than the traditional risk assessment paradigms. In this study, we explore a new approach to probabilistic risk assessment by developing and applying a BN as a meta-model for a Norwegian agricultural site. The model uses predictions from a process-based pesticide exposure model (World Integrated System for Pesticide Exposure - WISPE) in the exposure characterization and species sensitivity data from toxicity tests in the effect characterization. The probability distributions for exposure and effect are then combined into a risk characterization (i.e. the probability distribution of a risk quotient), which is a common measure of the exceedance of an environmentally safe exposure threshold. In this way, we aim to use the BN model to better account for variabilities of both pesticide exposure and effects to the aquatic environment than traditional risk assessment. Furthermore, the BN is able to link different types of future scenarios to the exposure assessment, taking into account both effects of climate change on pesticides fate and transport, and changes in pesticide application. We used climate projections from IPCC scenario A1B and two global circulation models (ECHAM5-r3 and HADCM3-Q0), which projected daily values of temperature and precipitation for Northern Europe until 2100. In Northern Europe, increased temperature and precipitation is expected to cause an increase in weed infestations, plant disease and insect pests, which in turn can result in altered agricultural practices, such as the use of new crop types and changes in pesticide application patterns. We used the WISPE model to link climate and pesticide application scenarios, environmental factors such as soil properties and field slope together with chemical properties (e.g. half-life in soil, water solubility, soil adsorption), to predict the pesticide exposure in streams adjacent to the agricultural fields. The model was parameterized and evaluated for five selected pesticides: the herbicides clopyralid, fluroxypyr-meptyl, and 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), and the fungicides prothiocanzole and trifloxystrobin. This approach enabled the estimation and visualization of probability distribution of the risk quotients representing the alternative climate models and application scenarios for the future time horizons 2050 and 2075. The currently used climate projections resulted in only minor changes in future risk directly through the meteorological variables. A stronger increase in risk was predicted for the scenarios with increased pesticide application, which in turn can represent an adaptation to a future climate with higher pest pressures. Further advancement of BN modelling as demonstrated herein is anticipated to aid targeted management of ecological risks in support of future research, industry and regulatory needs.

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Risk from pesticide mixtures – The gap between risk assessment and reality

Cited by 57 publications

References 50 publications

Pervasive exposure of wild small mammals to legacy and currently used pesticide mixtures in arable landscapes

Pervasive exposure of wild small mammals to legacy and currently used pesticide mixtures in arable landscapes

Ecological consequences of neonicotinoid mixtures in streams

Probabilistic risk assessment of pesticides under future agricultural and climate scenarios using a Bayesian network

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