Pesticide Risk Assessment Research Articles

Pesticide risk assessment in European agriculture: Distribution patterns, ban-substitution effects and regulatory implications

This study estimates the risks of agricultural pesticides on non-target organisms and the environment by combining detailed pesticide application data for 2015 with the Danish risk indicator Pesticide Load. We quantify and map the pesticide load of 59 pesticides on 28 crops and pastures in the EU. Furthermore, we investigate how recent bans on 14 pesticides in the EU could reduce pesticide use and load. Key findings show that the highest pesticide loads per hectare occur in Cyprus and the Netherlands due to high application rates and a high proportion of vegetable production. Chlorpyrifos caused the highest pesticide load per hectare on more than half of the assessed crops before its ban. The ban of 14 pesticides between 2018 and 2023 potentially reduced pesticide loads by 94%, but unobserved substitution effects could offset pesticide load reductions. Although bans on active substances are justified to control certain endpoint risks, our results highlight the potential weaknesses of bans that merely shift risks. These findings contribute to the ongoing scientific and societal discourse on efficiently mitigating pesticides' impacts on non-target organisms and the environment. However, to improve the evaluation of pesticide use, it is vital to enhance the reporting on detailed pesticide use for individual crop-pesticide combinations.

Systemic evaluation of novel acaricide hexythiazox for bioactivity improvement and risk reduction at the enantiomer level

Traditional risk assessments of chiral pesticides mainly depend on racemic form, which is often incomprehensive. This study conducted systemic investigations on the bioactivity, toxicity, and ecotoxicological effects of hexythiazox (HTZ) at the enantiomer level. The elution order and absolute configuration of HTZ enantiomers were determined. (4R, 5R)-(+)-HTZ exhibited 708 and 1719 times higher bioactivity against Tetranychus cinnabarinus and Tetranychus urticae eggs than (4S, 5S)-(−)-HTZ, respectively. Molecular docking indicated greater interactions between (4R, 5R)-(+)-HTZ and chitin synthase leading to higher bioactivity of (4R, 5R)-(+)-HTZ. However, (4S, 5S)-(−)-HTZ induced greater changes in protein and malondialdehyde content, and antioxidant and detoxification enzyme activities than (4R, 5R)-(+)-HTZ in earthworms. Furthermore, integrated biomarker response results indicated (4S, 5S)-(−)-HTZ exhibited higher toxic effects on earthworms than (4R, 5R)-(+)-HTZ. Finally, significant differentially expressed genes (DEGs) were observed in earthworms after exposure to (4R, 5R)-(+)-HTZ and (4S, 5S)-(−)-HTZ, respectively. These DEGs were mainly enriched in glycolysis/gluconeogenesis and purine metabolism pathways in earthworms. Additionally, six metabolism pathways were also enriched, including pyruvate metabolism, fatty acid biosynthesis, oxidative phosphorylation, citric acid cycle, fatty acid degradation, and ATP-binding cassette transporters. These findings suggest that earthworms exhibited enantiomer-specific responses to (4R, 5R)-(+)-HTZ and (4S, 5S)-(−)-HTZ. This study provides systemic insight into the toxicity mechanism of HTZ at the enantiomer level and the potential to develop (4R, 5R)-(+)-HTZ as a high-efficiency and low-risk pesticide.

Effect of chlorpyrifos-exposure on the expression levels of CYP genes in Daphnia magna and examination of a possibility that an up-regulated clan 3 CYP, CYP360A8, reacts with pesticides.

Daphnia magna is a test organism used for ecological risk assessments of pesticides, but little is known about the expression levels of cytochrome P450s (CYP)s and their changes after pesticide exposure in the less than 24-h-olds used for ecotoxicity tests. In this study, D. magna juveniles were exposed to 0.2 μg/L of chlorpyrifos under the conditions for acute immobilization test as specified by the OECD test guideline for 24 h, and then the gene expression was compared between the control and chlorpyrifos-exposure groups by RNA-sequencing analysis, with a focus on CYP genes. Among 38 CYP genes expressed in the control group, seven were significantly up-regulated while two were significantly down-regulated in the chlorpyrifos-exposure group. Although the sublethal concentration of chlorpyrifos did not change their expression levels so drastically (0.8 < fold change < 2.6), CY360A8 of D. magna (DmCYP360A8), which had been proposed to be responsible for metabolism of xenobiotics, was abundantly expressed in controls yet up-regulated by chlorpyrifos. Therefore, homology modeling of DmCYP360A8 was performed based on the amino acid sequence, and then molecular docking simulations with the insecticides that were indicated to be metabolized by CYPs in D. magna were conducted. The results indicated that DmCYP360A8 could contribute to the metabolism of diazinon and chlorfenapyr but not chlorpyrifos. These findings suggest that chlorpyrifos is probably detoxified by other CYP(s) including up-regulated and/or constitutively expressed one(s).

Landscapes of risk: A comparative analysis of landscape metrics for the ecotoxicological assessment of pesticide risk to bees

Abstract Pesticide use in agricultural landscapes creates environmental contamination that is heterogenous in space and time. Mobile organisms, such as bees, are exposed to multiple contamination sources when visiting patches that vary in the amount, timing and toxicity of pesticides used. Yet, environmental risk assessments (ERA) typically fail to consider this heterogeneity, in part because of the complexities of estimating exposure to different pesticides, and subsequent risk at organism‐relevant scales. We use pesticide assays of 269 bee‐collected pollen samples to understand the spatiotemporal variability of risk across a network of 41 field sites in southern Sweden. Observed bee pesticide risk is calculated based on compound‐specific residue quantifications in pollen and standardized toxicity data. We then compare the ability of three classes of landscape‐scale variables to predict this risk: (1) landscape composition and configuration metrics, (2) landscape load based on national pesticide use data and (3) predictions from a newly developed bee pesticide exposure model. Based on use data, 10 crops account for 81% of the total risk. We detected 49 pesticide compounds in bee‐collected pollen. Although herbicides and fungicides constitute the bulk of detected pesticides, both in frequency and amount quantified, unsurprisingly, insecticides contribute the most to risk. Landscape composition and configuration metrics did not predict observed pesticide risk, and interactions with bee species indicate taxa‐dependency in predictions. Landscape load predicted observed risk consistently between taxa. Risk estimates from our exposure model were strongly predictive but only when considering realized risk (i.e., risk estimates based on prior pesticide use information). Synthesis and applications. Predicting pesticide risk based on landscape patterns could enable landscape‐scale ERA. However, simple metrics of landscape pattern, such as proportion of agricultural land, are not sufficient. We found that risk observed in bee‐collected pollen was best predicted when integrating spatialized pesticide use in the pesticide exposure model, underscoring the importance of such data for research, monitoring and mitigation. Further, we propose a guidance framework for future landscape ecotoxicological risk analyses that clarifies data needs relative to risk prediction goals.

Occurrence, multiphase partition and risk assessment of organic amine pesticides in drinking water source of Xiang River, China.

The extensive use of organic amine pesticides (OAPs) in agricultural practices has resulted in the contamination of water environments, posing threats to ecosystems and human health. This study focused on the Xiang River (XR), a representative drinking water source, as the research area to investigate the occurrence characteristics of 34 OAPs. Diphenylamine emerged as the most prevalent OAP in surface water due to industrial and agricultural activities, while cycloate dominated in sediments due to cumulative effects. Generally, the concentration of OAPs in a mixed tap water sample was lower than those in surface water samples, indicating OAPs can be removed by water plants to a certain extent. The water-sediment distribution coefficients (kd) of ΣOAPs were much less than 1 L/g, the majority of OAPs maintained relatively high concentrations in water samples instead of accumulating in sediments. Furthermore, risk assessment revealed that carbofuran showed a moderate risk to the aquatic environment, with a risk quotient of 0.23, while other OAPs presented minor risks. This study provided crucial insights for regional pesticide management and control in the XR basin, emphasizing the importance of implementing strategies to minimize the release of OAPs into the environment and protect human health.

Updated peer review of the pesticide risk assessment of the active substance dichlorprop-P and variant dichlorprop-P-2-ethylhexyl.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Ireland, and co-rapporteur Member State, Poland, for the pesticide active substance dichlorprop-P and the variant dichlorprop-P-2-ethylhexyl and the assessment of applications for maximum residue levels (MRLs) are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative uses of dichlorprop-P as a herbicide on cereals, grassland and grass seed crops and of the variant dichlorprop-P-2-ethylhexyl as a plant growth regulator on citrus. MRLs were assessed in mandarin and lemon. The conclusions from 2018 were updated in 2024 following the request from the European Commission with regard to the endocrine-disrupting properties. The reliable end points, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Peer review of the pesticide risk assessment of the active substance quinolin-8-ol.

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Spain, and co-rapporteur Member State, the Netherlands, for the pesticide active substance quinolin-8-ol are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative use of quinolin-8-ol as a fungicide and bactericide against soil-borne pathogens in tomato cultivation in permanent greenhouses applied by drip irrigation. The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Improving a herbicide risk assessment model in paddy rice cultivation

Herbicides play a pivotal role in paddy rice cultivation by effectively controlling weeds, thus ensuring optimal resource utilisation and higher crop yields, making them indispensable for efficient rice production systems. However, herbicide applications could be related to potential environmental impacts such as water contamination and harm to non-target species, requiring special attention in their management to ensure the long-term sustainability of rice farming practices. The development and utilisation of robust risk assessment indicators for pesticides are essential tools in evaluating and mitigating potential environmental and human health hazards associated with pesticide use in agricultural practices. The Environmental Potential Risk Indicator for Pesticides (EPRIP) is not suitable for rice paddy cultivation due to its limitations in accurately assessing pesticide risk in this specific agricultural context. This is primarily attributed to the unique hydrological characteristics and ecosystem dynamics of paddy fields, which significantly differ from other agricultural systems. To address this issue and to enhance the accuracy of pesticide risk assessment in rice paddy fields, EPRIP has been improved and validated in two agricultural seasons. A synergistic approach involving field experiments and enhanced EPRIP model simulations was employed to assess the risk associated with the application of two herbicides in Italian paddy rice systems. The observed and model-predicted surface water (SW) concentrations exhibited a close alignment, though an overestimation was observed for groundwater (GW). In general, the estimated Risk Points (1 for SW and 4 for GW) were largely in accord with those derived from the field experiments (1 for SW and 3 for GW), suggesting that the refined EPRIP model holds promise for conducting reliable risk assessments following herbicide applications in such contexts.

Widespread Pesticide Distribution in the European Atmosphere Questions their Degradability in Air.

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved.

Occurrence and Risk Assessment of Pyrethroids and Organophosphorus Pesticides in the Middle Part of Mono River Basin

Occurrence and Risk Assessment of Pyrethroids and Organophosphorus Pesticides in the Middle Part of Mono River Basin

Identifying opportunities for high resolution pesticide usage data to improve the efficiency of endangered species pesticide risk assessment

The US pesticide registration and review process requires regular re-assessment of the risk of pesticide use to species listed under the Endangered Species Act (ESA), yet current assessment methods are inefficient when applied to hundreds of pesticides potentially impacting multiple species across a continent. Thus, many pesticides remain on the market without complete review. We assessed the value of using high resolution pesticide usage data in the risk assessment process to rapidly improve process efficiency. By using data available only in California, we found that high resolution data increased the number of species deemed not likely to be adversely affected by pesticides from <5 % to nearly 50 %. Across the contiguous US, we predicted that 48 % of species would be deemed not likely to be adversely affected using high resolution data, compared to 20 % without. However, if such data were available in just 11 states, 68 % of the available gains in efficiency could be obtained. Overall, using existing high-resolution data in California and a focused collection of such information from 11 other states could reduce risk assessment burden across the contiguous U.S. by one-quarter.

Evaluating contamination of seafood purchased from U.S. retail stores by persistent environmental pollutants, pesticides and veterinary drugs

Studies have reported health risks associated with seafood contamination, but few data exist on levels in commercially available seafood in the US. To better understand, the magnitude of foodborne exposure and identify vulnerable populations in the US, we measured concentrations of veterinary drugs, persistent organic pollutants (POPs) (polycyclic aromatic hydrocarbons [PAHs], polybrominated diphenyl ethers [PBDEs] and polychlorinated biphenyls [PCBs]), and legacy and current-use pesticides in 46 seafood samples purchased from retail outlets. Measured levels were used to estimate risk based on available maximum residue limits (MRLs) and toxic equivalence (TEQ) factors for analytes. Only seventeen of the 445 analytes were detected, at low substance frequencies. However, half of the samples tested positive for one or more analyte, with total concentrations ranging from below the limit of detection (LOD) to as high as 156 µg/kg wet weight. Based on the risk assessment for individual pesticides and veterinary drugs, the hazard quotients (HQ) were all <1, indicating no risk. However, for the sum of PCB126 and PCB167, two dioxin-like PCBs detected in our samples, the TEQ was nearly two orders of magnitude higher than the WHO limits in one catfish sample. Moreover, vulnerable groups with higher rates of consumption of specific fish types may face higher risks.

Effects of glyphosate and glyphosate‐based herbicide on learning and memory of the buff‐tailed bumblebee (Bombus terrestris)

AbstractThe decline of insect pollinators is a global concern, and the use of pesticides has been identified as a potential cause for it. Glyphosate‐based herbicides (GBHs) are the world's most used pesticides, but until recent years they have been claimed to be safe for non‐target organisms, such as pollinators. Using controlled arena experiments, we investigated the effects on the learning and long‐term memory of buff‐tailed bumblebees, Bombus terrestris (L.) (Hymenoptera: Apidae), of a single field‐realistic dose of glyphosate, both in its pure form and as a commercial herbicide (Roundup Gold) containing the active ingredient (a.i.) glyphosate and other co‐formulants. We found that glyphosate in its pure form caused deterioration in the learning ability of bumblebees in a 10‐color discrimination experiment; the glyphosate‐treated bees discriminated colors over 10% worse than the untreated control bees. However, the commercially used GBH (Roundup Gold) had no observable effect on the learning ability of the bumblebees, despite the fact that this herbicide contained the same amount of glyphosate as its pure form. These findings shed light on the potential risks associated with agrochemicals previously considered safe for pollinators and emphasize the need for comprehensive risk assessments of pesticides, including evaluations of cognitive functions in pollinators. Therefore, we propose that future pesticide testing should incorporate broader assessments to ensure the safety of pollinators in agricultural landscapes.

Food Pesticide Residues Monitoring and Health Risk Assessment

This Special Issue presents a share of the work published in the journal Foods on pesticide residue monitoring and risk assessment in food [...]

Statement on the refined environmental risk assessment and impact of the new classification for captan.

On 24 July 2020, the EFSA conclusion on the peer review of the pesticide risk assessment of the active substance captan drawn in the context of the renewal of approval of the active substance captan conducted in accordance with Commission Implementing Regulation (EC) No 844/2012 was approved. In December 2023, the European Commission asked EFSA to provide a statement on its view as regards the RMS's revised environmental risk assessment concerning some uses in pome fruits and cherries and the potential impact of the recent new classification recommended by RAC on the toxicological reference values of captan stated in the EFSA Conclusion. The current statement contains the conclusions of the considerations related to the environmental revised risk assessment performed by the RMS, Austria, and to the new classification proposed by RAC on the toxicological reference values.

Risk assessment of pesticides used in the eastern Avocado Belt of Michoacan, Mexico: A survey and water monitoring approach

Pesticides use raises concerns regarding environmental sustainability, as pesticides are closely linked to the decline of biodiversity and adverse human health outcomes. This study proposed a holistic approach for assessing the potential risks posed by pesticides for human health and the environment in the eastern region of Michoacan, where extensive agricultural lands, especially corn and avocado fields, surround the Monarch Butterfly Biosphere Reserve. We used a combination of qualitative (semi-structured interviews) and quantitative (chemical analysis) data. Fifty-five interviews with smallholder farmers allowed us to identify pesticide types, quantities, frequencies, and application methods. A robust and precise analytical method based on solid-phase extraction and LC-MS/MS was developed and validated to quantify 21 different pesticides in 16 water samples (rivers, wells, runoff areas). We assessed environmental and human health risks based on the pesticides detected in the water samples and reported in the interviews. The interviews revealed the use of 28 active ingredients, including glyphosate (29 % of respondents), imidacloprid (27 %), and benomyl (24 %). The pesticide analysis showed the presence of 13 different pesticides and degradation products in the water samples. The highest concentrations were found for imidacloprid (1195 ngL−1) and carbendazim (a degradation product of benomyl; 932 ngL−1), along with the metabolite of pyrethroid insecticides, 3-PBA (494 ngL−1). The risk assessment indicates that among the most used pesticides, the fungicide benomyl and carbendazim pose the highest risk to human health and aquatic ecosystems, respectively. This study unveils novel insights on agricultural practices for the avocado, a globally consumed crop that is undergoing rapid production expansion. It calls for the harmonisation of crop protection with environmental responsibility, safeguarding the health of the people involved and the surrounding ecosystems.

Ecological risk assessment for typical organophosphorus pesticides in surface water of China based on a species sensitivity distribution model

The ecological risks posed by widespread organophosphorus pesticide (OPs) pollution in the surface waters of China remain unclear. In this study, species sensitivity distribution (SSD) parametric statistical approaches were coupled with fully acute and chronic toxicity data to fit the sensitivity distributions of different aquatic species to five typical OPs: dimethoate, malathion, parathion-methyl, trichlorfon, and dichlorvos. Crustaceans exhibit the highest sensitivity to OPs, whereas algae are the least sensitive. The acute hazardous concentrations that affected 5 % of the species (HC5) were 0.112, 0.001, 0.001, 0.001, and 0.001 mg/L for dimethoate, malathion, parathion-methyl, trichlorfon, and dichlorvos, respectively, whereas their chronic HC5 values were 0.004, 0.004, 0.053, 0.001, and 0.0005 mg/L, respectively. Hence, dichlorvos is highly toxic and poses greater risk to non-target aquatic species. The evaluation data revealed varying geographical distribution characteristics of the ecological risks from OPs in 15 freshwater aquatic systems across different regions of China. Dichlorvos posed the highest risk in the basins of Zhejiang and Guangdong Provinces, with the highest chronic Risk Quotient (RQ) and Hazard Index (HI) at 9.34 and 9.92, respectively. This is much higher than what was collected and evaluated for foreign rivers (the highest chronic RQ and HI in foreign rivers were 1.65 and 2.24, respectively). Thus, dichlorvos in the surface waters of China poses a substantial ecological risk to aquatic organisms, and may endanger human health.

Dose addition in mixtures of compounds with dissimilar endocrine modes of action in in vitro receptor activation assays and the zebrafish sexual development test

BackgroundHuman exposure to pesticides is being associated with feminisation for which a decrease of the anogenital distance (AGD) is a sensitive endpoint. Dose addition for the cumulative risk assessment of pesticides in food is considered sufficiently conservative for combinations of compounds with both similar and dissimilar modes of action (MoA). ObjectiveThe present study was designed to test the dose addition hypothesis in a binary mixture of endocrine active compounds with a dissimilar mode of action for the endpoint feminisation. MethodsCompounds were selected from a list of chemicals of which exposure is related to a decrease of the AGD in rats and completed with reference compounds. These chemicals were characterised using specific in vitro transcriptional activation (TA) assays for estrogenic and androgenic properties, leading to a final selection of dienestrol as an ER-agonist and flutamide, linuron, and deltamethrin as AR-antagonists. These compounds were then tested in an in vivo model, i.e. in zebrafish (Danio rerio), using sex ratio in the population as an endpoint in order to confirm their feminising effect and MoA. Ultimately, the fish model was used to test a binary mixture of flutamide and dienestrol. ResultsStatistical analysis of the binary mixture of flutamide and dienestrol in the fish sexual development tests (FSDT) with zebrafish supported dose addition.

Application and Progress of Machine Learning in Pesticide Hazard and Risk Assessment.

Long-term exposure to pesticides is associated with the incidence of cancer. With the exponential increase in the number of new pesticides being synthesized, it becomes more and more important to evaluate the toxicity of pesticides by means of simulated calculations. Based on existing data, machine learning methods can train and model the predictions of the effects of novel pesticides, which have limited available data. Combined with other technologies, this can aid the synthesis of new pesticides with specific active structures, detect pesticide residues, and identify their tolerable exposure levels. This article mainly discusses support vector machines, linear discriminant analysis, decision trees, partial least squares, and algorithms based on feedforward neural networks in machine learning. It is envisaged that this article will provide scientists and users with a better understanding of machine learning and its application prospects in pesticide toxicity assessment.

Ecotoxicological risk assessment of pesticides against different aquatic and terrestrial species: using mechanistic QSTR and iQSTTR modelling approaches to fill the toxicity data gap

The toxicity prediction for newly designed or untested pesticides will reduce unnecessary chemical synthesis and animal testing, and contribute to the design of “greener and safer” pesticide chemicals.