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1.
BACKGROUND: For the registration of pesticides in the European Union, model simulations for worst‐case scenarios are used to demonstrate that leaching concentrations to groundwater do not exceed a critical threshold. A worst‐case scenario is a combination of soil and climate properties for which predicted leaching concentrations are higher than a certain percentile of the spatial concentration distribution within a region. The derivation of scenarios is complicated by uncertainty about soil and pesticide fate parameters. As the ranking of climate and soil property combinations according to predicted leaching concentrations is different for different pesticides, the worst‐case scenario for one pesticide may misrepresent the worst case for another pesticide, which leads to ‘scenario uncertainty’. RESULTS: Pesticide fate parameter uncertainty led to higher concentrations in the higher percentiles of spatial concentration distributions, especially for distributions in smaller and more homogeneous regions. The effect of pesticide fate parameter uncertainty on the spatial concentration distribution was small when compared with the uncertainty of local concentration predictions and with the scenario uncertainty. CONCLUSION: Uncertainty in pesticide fate parameters and scenario uncertainty can be accounted for using higher percentiles of spatial concentration distributions and considering a range of pesticides for the scenario selection. Copyright © 2010 Society of Chemical Industry  相似文献   

2.
Harmonisation of the assessment of pesticide leaching to groundwater for EU registration is desirable to minimise confusion in the decision-making process at EU level. Recently, the FOCUS groundwater scenarios have been developed for three chromatographic models (PEARL, PELMO and PRZM) to increase this harmonisation. This study investigates the role of dispersion parameterisation in explaining the cause of the differences in pesticide leaching calculated by these models. PEARL describes dispersion via a physical parameter, ie the dispersion length. PELMO and PRZM simulate dispersion via a numerical procedure which generates an effective dispersion length equal to 0.5 times the thickness of the numerical compartments. The hypothesis was tested that the difference in the dispersion length input parameter (ie 5 cm for PEARL and about 2.5 cm for PELMO and PRZM) is a major cause of the difference in calculated leaching. It was tested whether results of PEARL calculations with a dispersion length of 2.5 cm corresponded much better to results of PELMO or PRZM than results of PEARL calculations with a dispersion length of 5 cm. This was done by calculations for one substance and all nine FOCUS scenarios and by calculations for a range of substances and two FOCUS scenarios (Chateaudun and Sevilla). All calculations were for winter wheat and an application at 1 day before emergence. Both tests showed that reduction of the dispersion length from 5 to 2.5 cm in PEARL led to a much better correspondence between PEARL and either PELMO or PRZM. Hence the hypothesis was supported. It is likely that harmonisation of the dispersion length in the FOCUS groundwater scenarios would reduce the differences in calculated leaching between PEARL and PELMO or PRZM considerably for part of these scenarios.  相似文献   

3.
A comparative test was undertaken in order to identify the potential of existing mathematical models, including the rice water quality (RICEWQ) 1.6.4v model, the pesticide concentration in paddy field (PCPF-1) model and the surface water and groundwater (SWAGW) model, for calculating pesticide dissipation and exposure in rice paddies in Europe. Previous versions of RICEWQ and PCPF-1 models had been validated under European and Japanese conditions respectively, unlike the SWAGW model which was only recently developed as a tier-2 modelling tool. Two datasets, derived from field dissipation studies undertaken in northern Italy with the herbicides cinosulfuron and pretilachlor, were used for the modelling exercise. All models were parameterized according to field experimentations, as far as possible, considering their individual deficiencies. Models were not calibrated against field data in order to remove bias in the comparison of the results. RICEWQ 1.6.4v provided the highest agreement between measured and predicted pesticide concentrations in both paddy water and paddy soil, with modelling efficiency (EF) values ranging from 0.78 to 0.93. PCPF-1 simulated well the dissipation of herbicides in paddy water, but significantly underestimated the concentrations of pretilachlor, a chemical with high affinity for soil sorption, in paddy soil. SWAGW simulated relatively well the dissipation of both herbicides in paddy water, and especially pretilachlor, but failed to predict closely the pesticide dissipation in paddy soil. Both RICEWQ and SWAGW provided low groundwater (GW) predicted environmental concentrations (PECs), suggesting a low risk of GW contamination for the two herbicides. Overall, this modelling exercise suggested that RICEWQ 1.6.4v is currently the most reliable model for higher-tier exposure assessment in rice paddies in Europe. PCPF-1 and SWAGW showed promising results, but further adjustments are required before these models can be considered as strong candidates for inclusion in the higher-tier pesticide regulatory scheme.  相似文献   

4.
BACKGROUND: Key climatic factors influencing the transport of pesticides to drains and to depth were identified. Climatic characteristics such as the timing of rainfall in relation to pesticide application may be more critical than average annual temperature and rainfall. The fate of three pesticides was simulated in nine contrasting soil types for two seasons, five application dates and six synthetic weather data series using the MACRO model, and predicted cumulative pesticide loads were analysed using statistical methods. RESULTS: Classification trees and Pearson correlations indicated that simulated losses in excess of 75th percentile values (0.046 mg m(-2) for leaching, 0.042 mg m(-2) for drainage) generally occurred with large rainfall events following autumn application on clay soils, for both leaching and drainage scenarios. The amount and timing of winter rainfall were important factors, whatever the application period, and these interacted strongly with soil texture and pesticide mobility and persistence. Winter rainfall primarily influenced losses of less mobile and more persistent compounds, while short-term rainfall and temperature controlled leaching of the more mobile pesticides. CONCLUSIONS: Numerous climatic characteristics influenced pesticide loss, including the amount of precipitation as well as the timing of rainfall and extreme events in relation to application date. Information regarding the relative influence of the climatic characteristics evaluated here can support the development of a climatic zonation for European-scale risk assessment for pesticide fate.  相似文献   

5.
The assessment of human health risks resulting from the presence of metabolites in groundwater and food residues has become an important element in pesticide authorisation. In this context, the evaluation of mutagenicity is of particular interest and a paradigm shift from exposure‐triggered testing to in silico‐based screening has been recommended in the European Food Safety Authority (EFSA) Guidance on the establishment of the residue definition for dietary risk assessment. In addition, it is proposed to apply in silico predictions when experimental mutagenicity testing is not possible due to a lack of sufficient quantities of the pesticide metabolite. This, combined with animal welfare and economic considerations, has led to a situation where an increasing number of in silico studies are submitted to regulatory authorities. Whilst there is extensive experience with in silico predictions for mutagenicity in the chemical and pharmaceutical industry, their suitability in pesticide regulation is still insufficiently considered. Therefore, we herein discuss critical issues that need to be resolved to successfully implement (Quantitative) Structure‐Activity Relationship ((Q)SAR) as an accepted tool in pesticide regulation. For illustration purposes, the results of a pilot study are included. The presented study highlights a need for further improvement regarding the predictivity and applicability domain of (Q)SAR systems for pesticides and their metabolites, but also raises other questions such as model selection, establishment of acceptance criteria, harmonised approaches to the combination of model outputs into overall conclusions, adequate reporting and data sharing. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

6.
BACKGROUND: As part of the Dutch authorisation procedure for pesticides, an assessment of the effects on aquatic organisms in surface waters adjacent to agricultural fields is required. The peak concentration is considered to be the most important exposure endpoint for the ecotoxicological effect assessment. Macropore flow is an important driver for the peak concentration, so the leaching model PEARL was extended with a macropore module. The new model has two macropore domains: a bypass domain and an internal catchment domain. The model was tested against data from a field leaching study on a cracking clay soil in the Netherlands. RESULTS: Most parameters of the model could be obtained from site‐specific measurements, pedotransfer functions and general soil structural knowledge; only three macropore‐flow‐related parameters needed calibration. The flow‐related macropore parameters could not be calibrated without using the concentration in drain water. Sequential calibration strategies, in which firstly the water flow model and then the pesticide fate model are calibrated, may therefore be less suitable for preferential flow models. CONCLUSION: After calibration, PEARL could simulate well the observed rapid movement towards drains of two pesticides with contrasting sorption and degradation rate properties. The calibrated value for the fraction of the internal catchment domain was high (90%). This means that a large fraction of water entering the macropores infiltrates into the soil matrix, thus reducing the fraction of rapid flow. Copyright © 2011 Society of Chemical Industry  相似文献   

7.
气候变化对农药应用风险的影响   总被引:1,自引:0,他引:1  
全球气候变化的影响已成为世界关注的热点。它不仅影响作物产量,还会影响农药应用风险问题,包括农药使用量、农药环境行为、毒性效应等。我国是农药生产和使用大国,农药应用风险问题受到高度关注。本文结合国内外的相关研究分析了气温升高、降雨变化以及极端天气频发对农药应用的直接影响,气候变化所引起的土地利用变化对农药应用的间接影响,为气候变化下农药应用风险评估和控制提供科学依据和参考。  相似文献   

8.
The use of probabilistic risk assessment (PRA) for examining chemical impacts has become an important area of debate within the European Union. This paper describes a case study on probabilistic techniques to assess pesticide risks in the UK aquatic environment. The main aim of this paper is to demonstrate both the potential strengths and weaknesses of PRA for assessing pesticides when compared with the conventional deterministic approach, and to examine whether PRA is useful within the European regulatory context. The organophosphate insecticide, chlorpyrifos, was selected as a model compound and toxicity exposure ratios calculated using Monte Carlo analysis and different distributions of spray drift and toxicity values following application to top fruit. Chlorpyrifos is highly toxic to arthropods but less toxic to fishes. Species sensitivity followed a log-normal distribution when fitted to all toxicity data. Toxicity data quantity had little influence on species sensitivity distribution model parameters when n was greater than 10 species. Below this, estimates were less accurate and precise, possibly because of the inclusion of data from many different sources. Estimates of chlorpyrifos exposure derived from the standard spray drift model differed substantially from measurements of chlorpyrifos in European surface waters. When a distribution based on measured concentrations was used in a PRA, the risk of acute fish mortality was low, and the risk of acute arthropod mortality was lower than in other scenarios, although not negligible. If PRA is used to assess pesticides, risk managers need further guidance on how to conduct a PRA and what constitutes 'unacceptable risk' under EC Directive 91/414/EEC, as judgement is required when simple trigger values are no longer used.  相似文献   

9.
We describe the theory and current development state of the pesticide process module of the USDA-Agricultural Research Service Root Zone Water Quality Model, or RZWQM. Several processes which are significant in determining the fate of a pesticide application are included together in this module for the first time, including application technique, root uptake, ionic dissociation, soil depth dependence of persistence, volatilization, wicking upward in soil and aging of residues. The pesticide module requires a large number of parameters to run (as does the RZWQM model as a whole) and it is becoming clear that RZWQM will find most interest and use as part of a 'scenario' in which all data requirements are supplied and the predictions of the system compared with a real (usually partial) data set. Such a scenario may then be modified to examine the response of the system to changes in inputs. It also has significant potential as a technology transfer or teaching tool, providing detailed understanding of a specific agronomic system and its potential impacts on the environment.  相似文献   

10.
Concerns regarding the potential of pesticides to harm terrestrial non-target arthropod populations have led to the increased use of ecotoxicological test systems for terrestrial Non-target Arthropod risk assessment. Whilst some useful guidance on terrestrial invertebrate test systems is available, there are significant gaps in guidance for terrestrial non-target arthropod exposure estimates. The typical exposure in the standard test systems is by application of the test substance at the field rate (i. e. gram substance per hectare field) on to a two dimensional surface. However, under field conditions such a spray deposit will be diluted over the total available 3-Dimensional plant and soil surface. The recommendation is to use published leaf area index and crop interception values to standardize terrestrial dilution factors, which can then be used to predict exposure on a 3-Dimensional plant surface. Based on average crop/time specific LAI data for 26 crops, a surrogate off-crop dilution factor of 12 was calculated which can be used to convert 2-Dimensional spray drift exposure to 3-Dimensional off-crop plant surface exposure. Another significant terrestrial exposure guidance gap is how to calculate predicted environmental concentrations (PECs) for multiple application products. Based on spray interval and half-life data from 32 representative multiple application plant protection products, the typical worst-case PECs for accumulation of residues were calculated after up to 8 applications. These data showed that Multiple Application Factors (MAFs = accumulated PEC/initial PEC), increased from 1 to 3.5 after 1 to 8 applications, respectively. Finally, overall 90th percentile spray deposit values have been proposed for deriving off-crop multiple applications PECs (1 to 8 applications) based on published spray drift data. The recommended equations for terrestrial exposure assessment include the use of:-application rate, the 90th percentile drift value, the multiple application factors (MAF) and the standard dilution factor (for 3-Dimensional plant surface). This proposed terrestrial non-target arthropod exposure scheme is comparable with other first tier exposure assessment schemes eg aquatic exposure assessment.  相似文献   

11.
Concerns regarding the potential of pesticides to harm terrestrial non-target arthropod populations have led to the increased use of ecotoxicological test systems for terrestrial Non-target Arthropod risk assessment. Whilst some useful guidance on terrestrial invertebrate test systems is available, there are significant gaps in guidance for terrestrial non-target arthropod exposure estimates. The typical exposure in the standard test systems is by application of the test substance at the field rate (i. e. gram substance per hectare field) on to a two dimensional surface. However, under field conditions such a spray deposit will be diluted over the total available 3-Dimensional plant and soil surface. The recommendation is to use published leaf area index and crop interception values to standardize terrestrial dilution factors, which can then be used to predict exposure on a 3-Dimensional plant surface. Based on average crop/time specific LAI data for 26 crops, a surrogate off-crop dilution factor of 12 was calculated which can be used to convert 2-Dimensional spray drift exposure to 3-Dimensional off-crop plant surface exposure. Another significant terrestrial exposure guidance gap is how to calculate predicted environmental concentrations (PECs) for multiple application products. Based on spray interval and half-life data from 32 representative multiple application plant protection products, the typical worst-case PECs for accumulation of residues were calculated after up to 8 applications. These data showed that Multiple Application Factors (MAFs = accumulated PEC/initial PEC), increased from 1 to 3.5 after 1 to 8 applications, respectively. Finally, overall 90th percentile spray deposit values have been proposed for deriving off-crop multiple applications PECs (1 to 8 applications) based on published spray drift data. The recommended equations for terrestrial exposure assessment include the use of:-application rate, the 90th percentile drift value, the multiple application factors (MAF) and the standard dilution factor (for 3-Dimensional plant surface). This proposed terrestrial non-target arthropod exposure scheme is comparable with other first tier exposure assessment schemes eg aquatic exposure assessment.  相似文献   

12.
An improved simulation model (PCPF-1) has been evaluated for the prediction of the fate of mefenacet in an experimental paddy field. This model simulates the fate and transport of pesticide in paddy water and the top 1 cm of paddy soil. Observed concentrations of mefenacet in the paddy water and the surface soil exponentially decreased from their maximum concentrations of 0.70 mg litre(-1) and 11.3 mg kg(-1), respectively. Predicted mefenacet concentrations both in the water and surface soil were in excellent agreement with those measured during the first 2 weeks after herbicide application, but concentrations in paddy water were appreciably overestimated thereafter. The model simulated mefenacet losses through runoff, percolation and degradation to be respectively 41.9%, 6.4% and 57.3% of applied, and the mass balance error was about -6%. The model simulation implied that drainage and seepage control, especially shortly after application when herbicide concentrations are high, is essential for preventing pesticide losses from paddy fields. In focusing on pesticide concentrations in this early period the PCPF-1 model can be a beneficial tool for risk assessment of pesticide losses and in the evaluation of agricultural management for reducing pesticide pollution associated with paddy rice production.  相似文献   

13.
The Root Zone Water Quality Model (RZWQM) is a one-dimensional, numerical model for simulating water movement and chemical transport under a variety of management and weather scenarios at the field scale. The pesticide module of RZWQM includes detailed algorithms that describe the complex interactions between pesticides and the environment. We have simulated a range of situations with RZWQM, including foliar interception and washoff of a multiply applied insecticide (chlorpyrifos) to growing corn, and herbicides (alachlor, atrazine, flumetsulam) with pH-dependent soil sorption, to examine whether the model appears to generate reasonable results. The model was also tested using chlorpyrifos and flumetsulam for the sensitivity of its predictions of chemical fate and water and pesticide runoff to various input parameters. The model appears to generate reasonable representations of the fate and partitioning of surface- and foliar-applied chemicals, and the sorption of weakly acidic or basic pesticides, processes that are becoming increasingly important for describing adequately the environmental behavior of newer pesticides. However, the kinetic sorption algorithms for charged pesticides appear to be faulty. Of the 29 parameters and variables analyzed, chlorpyrifos half-life, the Freundlich adsorption exponent, the fraction of kinetic sorption sites, air temperature, soil bulk density, soil-water content at 33 kPa suction head and rainfall were most sensitive for predictions of chlorpyrifos residues in soil. The latter three inputs and the saturated hydraulic conductivity of the soil and surface crusts were most sensitive for predictions of surface water runoff and water-phase loss of chlorpyrifos. In addition, predictions of flumetsulam (a weak acid) runoff and dynamics in soil were sensitive to the Freundlich equilibrium adsorption constant, soil pH and its dissociation coefficient.  相似文献   

14.
农药职业健康风险评估方法   总被引:3,自引:1,他引:2  
农药职业健康风险评估是评价农药对使用者和再进入施药区域劳动者健康危害的方法体系。根据国际风险评估的原理和流程,主要介绍了农药职业健康风险评估的方法,即采用安全剂量与不同场景农药暴露量的比值来评估非遗传毒性农药的健康风险。并阐述了暴露模型、出发点和不确定因子等概念及其运用。最后,从建立符合中国国情的风险评估方法、基础数据库及加快农药毒理学良好实验室(GLP实验室)建设等几方面,就我国应该如何开展农药职业健康风险评估工作提出了可行性建议。  相似文献   

15.
Andr  L CARVALHO 《干旱区科学》2022,14(4):359-373
Understanding the dynamics of soil organic carbon (SOC) is of fundamental importance in land use and management, whether in the current researches or in future scenarios of agriculture systems considering climate change. In order to evaluate SOC stock of the three districts (Delmiro Gouveia, Pariconha, and Inhapi districts) in the semi-arid region of Brazil in rainfed and irrigated agriculture systems under different climate scenarios using the Century model, we obtained RCP4.5 and RCP8.5 climate scenarios derived from the Eta Regional Climate Model (Eta-HadGEM2-ES and Eta-MIROC5) from the National Institute for Space Research, and then input the data of bulk density, pH, soil texture, maximum temperature, minimum temperature, and rainfall into the soil and climate files of the Century model. The results of this study showed that the Eta-HadGEM2-ES model was effective in estimating air temperature in the future period. In rainfed agriculture system, SOC stock under the baseline scenario was lower than that under RCP4.5 and RCP8.5 climate scenarios, while in irrigated agriculture system, SOC stock in the almost all climate scenarios (RCP4.5 and RCP8.5) and models (Eta-HadGEM2-ES and Eta-MIROC5) will increase by 2100. The results of this study will help producers in the semi-arid region of Brazil adopt specific agriculture systems aimed at mitigating greenhouse gas emissions.  相似文献   

16.
农药环境影响试验数据是开展农药环境风险评估的重要依据,而试验试材又是影响试验数据可靠性的关键因素。农药生态毒理学和环境归趋试验涉及的试材种类繁多,主要包括土壤试材和20多种生物试材,规范化管理难度较大。本文归纳总结了国内外农药环境影响试验准则中对试材的要求,调研了目前国内农药环境影响实验室的试材使用情况,并对试材规范化管理提出了建议。  相似文献   

17.
中国食品中农药MRL标准对急性膳食暴露评估需求的研究   总被引:1,自引:1,他引:0  
为了评估当前国内相关农药最大残留限量(MRL)标准及我国居民的急性膳食暴露风险水平,采用FAO/WHO农药残留专家联席会议(JMPR)推荐的农药残留急性膳食暴露评估方法,利用我国居民大份额膳食消费数据、国内登记农药的规范残留试验数据和JMPR推荐的农药毒理学数据,对我国普通人群、0~6岁儿童和育龄妇女的农药残留摄入情况进行了急性膳食暴露评估。结果表明:白菜中的虫螨腈和丙森锌、甘蓝中的高效氯氰菊酯和灭多威对三类人群的国家估算急性暴露水平(NESTI)均大于急性参考剂量(ARf D);香蕉中的氟硅唑对0~6岁儿童和普通人群的NESTI分别为ARf D值的300%和160%;苹果中的二氰蒽醌、甘蓝中的高效氯氟氰菊酯、花椰菜中的阿维菌素及番茄中的丙森锌仅对0~6岁儿童有较高的急性膳食暴露风险;儿童相比其他人群摄入农药残留的急性膳食暴露风险更高、概率更大。建议我国采取相应的风险管理措施,降低农药残留摄入的急性膳食风险,同时尽快完善短期膳食消费数据库和农药残留数据库,在制定农药MRL标准时进行相应的急性膳食暴露评估,以保障消费者的农药急性膳食暴露风险在可接受水平。  相似文献   

18.
Sensitivity analyses using a one-at-a-time approach were carried out for leaching models which have been widely used for pesticide registration in Europe (PELMO, PRZM, PESTLA and MACRO). Four scenarios were considered for simulation of the leaching of two theoretical pesticides in a sandy loam and a clay loam soil, each with a broad distribution across Europe. Input parameters were varied within bounds reflecting their uncertainty and the influence of these variations on model predictions was investigated for accumulated percolation at 1-m depth and pesticide loading in leachate. Predictions for the base-case scenarios differed between chromatographic models and the preferential flow model MACRO for which large but transient pesticide losses were predicted in the clay loam. Volumes of percolated water predicted by the four models were affected by a small number of input parameters and to a small extent only, suggesting that meteorological variables will be the main drivers of water balance predictions. In contrast to percolation, predictions for pesticide loss were found to be sensitive to a large number of input parameters and to a much greater extent. Parameters which had the largest influence on the prediction of pesticide loss were generally those related to chemical sorption (Freundlich exponent nf and distribution coefficient Kf) and degradation (either degradation rates or DT50, QTEN value). Nevertheless, a significant influence of soil properties (field capacity, bulk density or parameters defining the boundary between flow domains in MACRO) was also noted in at least one scenario for all models. Large sensitivities were reported for all models, especially PELMO and PRZM, and sensitivity was greater where only limited leaching was simulated. Uncertainty should be addressed in risk assessment procedures for crop-protection products.  相似文献   

19.
BACKGROUND: Monitoring studies revealed high concentrations of pesticides in the drainage canal of paddy fields. It is important to have a way to predict these concentrations in different management scenarios as an assessment tool. A simulation model for predicting the pesticide concentration in a paddy block (PCPF‐B) was evaluated and then used to assess the effect of water management practices for controlling pesticide runoff from paddy fields. RESULTS: The PCPF‐B model achieved an acceptable performance. The model was applied to a constrained probabilistic approach using the Monte Carlo technique to evaluate the best management practices for reducing runoff of pretilachlor into the canal. The probabilistic model predictions using actual data of pesticide use and hydrological data in the canal showed that the water holding period (WHP) and the excess water storage depth (EWSD) effectively reduced the loss and concentration of pretilachlor from paddy fields to the drainage canal. The WHP also reduced the timespan of pesticide exposure in the drainage canal. CONCLUSIONS: It is recommended that: (1) the WHP be applied for as long as possible, but for at least 7 days, depending on the pesticide and field conditions; (2) an EWSD greater than 2 cm be maintained to store substantial rainfall in order to prevent paddy runoff, especially during the WHP. Copyright © 2010 Society of Chemical Industry  相似文献   

20.
贺文艳  毛萌 《农药学学报》2018,20(2):146-152
五氟磺草胺作为苗后除草剂被广泛应用于水稻田中杂草的防除,其对水生植物、陆生植物和土壤微生物群落可能存在潜在风险,因此,对五氟磺草胺在水土环境中的转化规律与归趋开展定量研究,已受到学者们的关注。本文对五氟磺草胺在稻田水土环境中的吸附、降解以及对周围环境影响方面的研究进展进行了综述、归纳和分析。指出目前对五氟磺草胺在土壤中吸附的研究报道较少,尚未见有关其在水土环境中运移方面的研究,同时应加强其对水土环境风险评估的研究。  相似文献   

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