Pesticide Application Rates Research Articles

Quantifying residents' exposure to agricultural pesticides using new geospatial approaches

A better understanding of environmental exposure to agricultural pesticides is crucial for public health, regulatory and management purposes. Residents in close vicinity to agricultural fields are likely to be more exposed to pesticides. In that context, an innovative geospatial approach for mapping estimates of agricultural pesticide exposure was developed in this study.Data on pesticide application rates, high-resolution annual datasets of the geographic distribution of crops, and the 100x100m grid population dataset were utilized to complete this analysis in Wallonia (Belgium) over the period 2015-2019. Pesticide exposure metrics were estimated using a buffer-based exposure model by conducting neighborhood analysis within a 1000m buffer radius. Subsequently, a population weighted method was used to ‘up-scale’ the exposure data to administrative levels. In a limited validation effort, model estimates were compared with pesticide measurements in air collected at 12 stations during the period 2015-2016.The results present the first modeling map of environmental exposure to agricultural pesticides for the whole of the Walloon region. The northern part of the Sambre-Meuse axis demonstrates more intensive agriculture and the highest pesticide weighted exposure indices. The majority of the population resides near agricultural areas, with only 4% living in regions that lack crops within a 1000m radius, primarily in the central areas of large cities. A positive trend association between pesticide measures in air and the index was observed at the different stations, nevertheless further validation efforts are needed to accurately compare the same active ingredients.This work gives a valuable basis for research and environmental health actions in Belgium. Maps highlight areas where human biomonitoring and epidemiological studies should be implemented to investigate the impact of potential environmental exposure to pesticides. This information helps policy-makers to take measures to control and reduce the load of agricultural pesticides in the environment.

Influence of Pesticide Application Method, Timing, and Rate on Contamination of Nectar with Systemic and Nonsystemic Pesticides.

Exposure to pesticides is one potential factor contributing to the recent loss of pollinators and pollinator diversity. Few studies have specifically focused on the relationship between pesticide management during ornamental plant production and contamination of nectar. We evaluated contamination of nectar in Salvia 'Indigo Spires' (Salvia longispicata M. Martens & Galeotti × S. farinacea Benth.) associated with applications of the systemic insecticide thiamethoxam, and the nonsystemic fungicides boscalid and pyraclostrobin. Applications were made at the labeled rates for the commercially available products, and we compared the influence of application method (drench vs. spray), timing (relative to flowering), and rate (low vs. high) for each pesticide. Nectar was sampled using 50-µL microcapillary tubes and analyzed by liquid chromatography-tandem mass spectrometry. The results indicate that concentrations from the spray application resulted in the least contamination of nectar with the systemic thiamethoxam, with lower concentrations occurring when thiamethoxam was applied before blooming at the lowest rate. Concentrations of thiamethoxam and its metabolite clothianidin were detected in nectar in all treatments (regardless of the method, timing, or rate of application), and ranged from 3.6 ± 0.5 ng/mL (spray-applied before blooming, low rate) to 1720.0 ± 80.9 ng/mL (drench-applied after blooming, high rate). Residues of clothianidin in nectar ranged from below quantification limits (spray-applied before blooming, low rate) to 81.2 ± 4.6 ng/mL (drench-applied after blooming, high rate). Drench applications resulted in the highest levels of nectar contamination with thiamethoxam, and exceeded published median lethal concentrations (LC50s/median lethal doses for native bees and/or honeybees in all cases). Spray treatments resulted in nectar concentrations exceeding published LC50s for some bee species. In comparison, all nonsystemic treatments resulted in concentrations much lower than the published no-observable-effect doses and sublethal toxicity values, indicating low risks of toxicity. Environ Toxicol Chem 2024;001:1-12. © 2024 SETAC.

Temporal analysis of water chemistry and smallmouth bass (Micropterus dolomieu) health at two sites with divergent land use in the Susquehanna River watershed, Pennsylvania, USA

Monitoring wild fish health and exposure effects in impacted rivers and streams with differing land use has become a valuable research tool. Smallmouth bass (Micropterus dolomieu) are a sensitive, indicator species that exhibit signs of immunosuppression and endocrine disruption in response to water quality changes and contaminant exposure. To determine the impact of agriculture and development on smallmouth bass health, two sites (a developed/agriculture site and a forested site) in the Susquehanna River watershed, Pennsylvania were selected where bass and water chemistry were sampled from 2015 to 2019. Smallmouth bass were sampled for histopathology to assess parasite and macrophage aggregate density in the liver and spleen, condition factor (Ktl), hepatic gene transcript abundance, hepatosomatic index (HSI), and a health assessment index (HAI). Land use at the developed/agriculture site included greater pesticide application rates and phytoestrogen crop cover and more detections and higher concentrations of pesticides, wastewater-associated contaminants, hormones, phytoestrogens, and mycotoxins than at the forested site. Additionally, at the developed/agriculture site, indicators of molecular changes, including oxidative stress, immune/inflammation, and lipid metabolism-related hepatic gene transcripts, were associated with more contaminants and land use variables. At both sites, there were multiple associations of contaminants with liver and/or spleen macrophage aggregate density, indicating that changes at the molecular level seemed to be a better indicator of exposures unique to each site. The findings illustrate the importance of timing for land management practices, the complex mixtures aquatic animals are exposed to, and the temporal changes in contaminant concentration. Agricultural practices that affect hepatic gene transcripts associated with immune function and disease resistance were demonstrated which could negatively affect smallmouth bass populations.

Managing ecosystem services in oleaginous forests for bioenergy provision and climate change mitigation

Oleaginous forests provide diverse ecosystem services, including timber, seed yield (a vital feedstock for biodiesel production), and substantial carbon savings. These carbon savings encompass carbon sequestration related to timber growth and carbon savings resulting from substituting fossil fuel with biodiesel. However, oleaginous forests are vulnerable to seed wasp attacks (disservice), which significantly threaten both seed yield and carbon savings. Using an integrated ecological-economic model that includes Faustmann's Land Expectation Value model and a pest damage control model, we aim to understand the intricate relationship among multiple ecosystem services and disservices of oleaginous forests. The results reveal four distinct phases contingent on varying pesticide application rates: the pesticide under-use phase, substitution phase, complementary phase, and over-use phase. Notably, a potential avenue to minimize pest damage is identified during the complementary phase by reducing the optimal rotation age at the expense of decreased carbon sequestration and bioenergy provision, posing a challenge to climate change mitigation. These findings have implications for formulating policies to manage conflicting ecosystem services of energy forests, offering valuable insights into the intersection of sustainable forest management and climate policy.

Pesticide residues in boreal arable soils: Countrywide study of occurrence and risks

Large volumes of pesticides are applied every year to support agricultural production. The intensive use of pesticides affects soil quality and health, but soil surveys on pesticide residues are scarce, especially for northern Europe. We investigated the occurrence of 198 pesticide residues, including both banned and currently used substances in 148 field sites in Finland. Results highlight that pesticide residues are common in the agricultural soils of Finland. A least one residue was found in 82% of the soils, and of those 32% contained five or more residues. Maximum total residue concentration among the conventionally farmed soils was 3043 μg/kg, of which AMPA and glyphosate contributed the most. Pesticide residues were also found from organically farmed soils, although at 75–90% lower concentrations than in the conventionally farmed fields. Thus, despite the application rates of pesticides in Finland being generally much lower than in most parts of central and southern Europe, the total residue concentrations in the soils occurred at similar or at higher levels. We also established that AMPA and glyphosate residues in soil are significantly higher in fields with cereal dominated rotations than in grass dominated or cereal–grass rotations. However, risk analyses for individual substances indicated low ecological risk for most of the fields. Furthermore, the total ecological risk associated with the mixtures of residues was mostly low except for 21% of cereal dominated fields with medium risk. The results showed that the presence of mixtures of pesticide residues in soils is a rule rather than an exception also in boreal soils. In highly chemicalized modern agriculture, the follow-up of the residues of currently used pesticides in national and international soil monitoring programs is imperative to maintain soil quality and support sustainable environment policies.

Economic evaluation of cowpea production under different spraying regimes in three different southern agro-ecologies of Nigeria

This study was carried out to evaluate different spraying regimes for the production of two cowpea varieties (Ife Brown and IT2246) in the humid southwest agro-ecologies of Nigeria in order to recommend optimum spraying regimes for cowpea production in the zone. Agronomic data were collected from trials conducted in 2020 and 2021 in outstations representative of the broad agroecologies of this region of Nigeria. The data were subjected to partial budget and marginal rate-ofreturn analyses. The results show varying potential of the cowpea varieties and spraying regimes across locations. Ife Brown cowpea can be produced profitably under forest agro-ecologies (Ibadan) with three spraying regimes at a moderate application rate of 200 litres per hectare. In the derived savannah, the Ife Brown and IT2246 varieties were profitable with four spraying regimes at a moderate application rate of 200 litres per hectare, while planting Ife Brown with two regimes of spraying at moderate pesticide application rate of 200 litres per hectare was profitable for the southern Guinea savannah agro-ecologies.

Differences Between Farmers and Crop Protection Service Providers in the Use of Pesticides

EU-wide statistics on the use of pesticides in agriculture are available on the quantities placed on the market, but data on actual use in practice are limited. In this study, comparative data on pesticide use and resistance management were collected for a region with mixed agriculture (arable and animal husbandry) in Austria. Based on individual pesticide records of 30 farmers and 10 service providers who perform plant protection tasks for 30 farms, the average application rates of pesticides, the change of the active substance group as well as the shortfalls and exceedances of the maximum permissible application rate were compared. Most farmers and service providers usually make a well-considered change in the group of active substances to avoid the development of resistance. Exceedances and underdosing of authorised application rates were found for both groups of people, with farmers tending to deviate more often. The applications amounts were largely in compliance with the law, however, in 3.69% of the 2387 evaluated uses of pesticides, the authorised application rate was exceeded. This excess was found somewhat more frequently among farmers than service providers. The application rate excesses can be attributed to technical overruns due to differences between actually farmed and formally declared area, confusion caused by complex application instructions but also by intention. To avoid inadequate information on authorised application rates and to simplify information gathering, the development of databases and apps that take into account not only the indisputably essential aspect of correct registration, but especially the user and user-friendliness, would be of great benefit and value. Packaging sizes adapted to different requirements and farm sizes would also be advantageous. High priority should be given to the technical training of users and sales personnel. This can contribute to higher professionalism in the use of pesticides in terms of compliance and resistance management, but also to the reduction of pesticides.

When pesticide reduction objectives meet business as usual: Possible impacts on the crop sector in Latvia

The European Union (EU) has set forth ambitious political objectives aimed at mitigating the adverse impacts of agriculture on climate, environment, and human health. Among the measures which are expected to help reach the goals, an important objective is significant reduction of pesticide usage, as outlined in the EU’s ”From Farm to Fork” strategy. This study seeks to assess the potential financial implications of the reduction of pesticide use, focusing on the major crops cultivated in Latvia. Scenario simulations have been conducted to examine the consequences of pesticide usage intensity on profitability, yields, and consumption of fertilisers. The evaluation encompasses winter and spring wheat, along with winter rapeseed, which account for 80% of the total pesticide usage in Latvia. It is assumed that farmers continue to produce the same crops, using their current level of knowledge and adjusting production technology to the reduced pesticides application rates. The analysis leads to the conclusion that in order to attain a reduction in pesticide use by 61% from the 2021 level (or 53% from the 2015–2017 level), the application rate of pesticides needs to be limited to 0.78 kg ha −1 of active substance for conventionally produced winter and spring wheat as well as winter rapeseed, and in addition to that the area used for these crops should be reduced by 33% (replaced with organic production). However, if the market prices of crops, the amount of public support and production costs do not change, the financial implications for the agricultural sector could be severe — yearly farm profit in the analysed sector could decrease by 41% or by EUR 130 mln.

Unveiling the Epoch: Exploring Pesticide Utilization and Trade Trends Globally and Regionally from 1990 to 2020

Over the past three decades, a rapid increase in pesticide usage has played a central role in transforming the landscape of modern agriculture. The objective of this research is to conduct a comprehensive analysis of changes in pesticide usage from 1990 to 2020, emphasizing the complexity of global trends, environmental impacts, and pesticide trade dynamics. This study utilizes agri-environmental indicators and relies on the latest statistical data from FAOSTAT in 2022. The applied research method is a quantitative approach based on secondary data.The research findings indicate that global pesticide usage reached 2.7 million tons in 2020, with an average of 1.8 kg/ha. Although reaching a stable level, pesticide trade experienced a significant increase, particularly in the disinfectant category. Over the past three decades, there has been an approximately 50 percent increase in pesticide usage, especially in herbicides. Per capita analysis shows a relatively stable consumption rate, although there is an increase in pesticide usage per unit of agricultural land. Regional levels reveal significant disparities, with Asia as the largest contributor, Europe implementing strict policies, the Americas having the highest usage rates, Oceania experiencing low trade, and Africa applying low usage rates. Some countries, such as Saint Lucia, exhibit high pesticide application rates per unit of agricultural land, and this variation requires in-depth analysis to understand influencing factors. To mitigate negative impacts, international cooperation, the development of sustainable technologies, and a profound understanding of pesticide applications are necessary. Therefore, more effective and sustainable agricultural policies need to be designed to protect the environment and human health.

Incorporating climate projections in the environmental risk assessment of pesticides in aquatic ecosystems.

Global climate change will significantly impact the biodiversity of freshwater ecosystems, both directly and indirectly via the exacerbation of impacts from other stressors. Pesticides form a prime example of chemical stressors that are expected to synergize with climate change. Aquatic exposures to pesticides might change in magnitude due to increased runoff from agricultural fields, and in composition, as application patterns will change due to changes in pest pressures and crop types. Any prospective chemical risk assessment that aims to capture the influence of climate change should properly and comprehensively account for the variabilities and uncertainties that are inherent to projections of future climate. This is only feasible if they probabilistically propagate extensive ensembles of climate model projections. However, current prospective risk assessments typically make use of process-based models of chemical fate that do not typically allow for such high-throughput applications. Here, we describe a Bayesian network model that does. It incorporates a two-step univariate regression model based on a 30-day antecedent precipitation index, circumventing the need for computationally laborious mechanistic models. We show its feasibility and application potential in a case study with two pesticides in a Norwegian stream: the fungicide trifloxystrobin and herbicide clopyralid. Our analysis showed that variations in pesticide application rates as well as precipitation intensity lead to variations in in-stream exposures. When relating to aquatic risks, the influence of these processes is reduced and distributions of risk are dominated by effect-related parameters. Predicted risks for clopyralid were negligible, but the probability of unacceptable future environmental risks due to exposure to trifloxystrobin (i.e., a risk quotient >1) was 8%-12%. This percentage further increased to 30%-35% when a more conservative precautionary factor of 100 instead of 30 was used. Integr Environ Assess Manag 2024;20:384-400. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Performance matching of common pesticides in banana plantations on the surface of banana leaves at different growth stages.

The effective deposition of pesticide droplets on a target leaf surface is critical for decreasing pesticide application rates. The wettability between the target leaf surface and the pesticide spray liquid should be investigated in depth, with the aim of enhancing the adhesion of pesticide solutions. The wetting and deposition behavior of pesticides on target leaves depends on the properties of the liquid and the physical and chemical properties of the leaves. The physical and chemical properties of leaves vary with growth stage. This study aims to investigate the wetting behavior of banana leaf surfaces at different stages. The microstructures and chemical compositions of banana leaf surfaces at different stages were studied using modern methods. The surface structure of banana leaves exhibited a wide variety of characteristics at different growth stages, and the chemical composition changed marginally. The surface free energy (SFE) and polar and non-polar components of banana leaves at different growth stages were measured by examining the contact angles (CA) of different test solutions on the surface of banana leaves. Previous research has suggested that changes in the CA and SFE correlate with changes in leaf surface wettability. In general, the new upper leaves of banana trees are composed of polar components and exhibit hydrophobicity. Non-polar components become dominant as the leaf grows. The back surface of banana leaves was non-polar at all growth stages, with a trend that was opposite to that of the front surface. The critical surface tension of the banana leaf surface at different growth stages ranged from 7.83 to 24.22 mN m-1 , thus falling into the category of a low-energy surface. The surface roughness and chemical characteristics of banana leaves affected the wettability of the leaf surface. Differences in the free energy and the polar and non-polar components of the leaf surface at were seen at different growth stages. This study provides a favorable reference for the rational control of pesticide spraying parameters and the enhancement of wetting and adhesion of the solution on banana leaf surfaces. © 2023 Society of Chemical Industry.

Measuring the Impact of Relative Deprivation on Tea Farmers’ Pesticide Application Behavior: The Case of Shaanxi, Sichuan, Zhejiang, and Anhui Province, China

Reducing chemical interaction within core farming tactics has gained much attention worldwide due to ever-increasing water, soil, and air pollution trends caused by various agricultural activities. Since, in the developing countries, tea is primarily produced conventionally, clarifying the impact of relative deprivation on the pesticide application rate of tea farmers is conducive to promoting the reduction of pesticides and the green development of the tea industry. Thus, based on extensive literature reviews, the study constructs a theoretical framework of relative deprivation and pesticide application rate by tea farmers. Moreover, the moderating effect of external intervention and behavioral factors has also been assessed. A data set of 786 tea farmers’ responses from Shaanxi, Sichuan, Zhejiang, and Anhui provinces has been utilized to test, outline and validate the proposed framework. We utilized the Ordered Probit model to measure the psychological fluctuation of tea farmers. The results are as follows. (i) The more substantial their perception of relative deprivation, the more tea farmers tend to increase the application rate. (ii) In external interventions, the degree of government regulation can not only directly promote the reduction of pesticide application but also play a negative regulatory role between the relative deprivation and the amount of pesticide applied by tea farmers. Although the degree of community control can directly promote the reduction of pesticide application by tea farmers, its regulating effect is insignificant. (iii) Regarding behavioral ability, the management scale can directly promote the reduction of pesticide application by tea farmers, but its regulating impact is not significant. Thus, government should highlight the importance of organic and environmentally friendly tea cultivation and encourage tea farmers to reduce pesticide application. Along with the market regulation, point-of-sale testing and traceability of pesticide residues should continue to be consolidated, strengthened and improved.

Pesticide Utilization in Myanmar and effects on Human Health and Environment

Human health and environmental hazards associated with pesticide handling are common in developing countries, as farmers and agricultural workers frequently lack proper personal protective equipment and may be unable to understand labels with safety instructions. Importation, distribution, use, storage, and disposal of pesticides. Pesticide utilization globally is increasing every year and Myanmar pesticide utilization is also increasing year by year. Its global rank of utilization is 86 and the quantity of pesticide application dosage is 1.4 kg per hectare. Although Myanmar's pesticide application rate per hectare is not as high as in other countries, ignorance of the pre-harvest interval after pesticide application, failure to follow labeling guidelines, calibration, misuse, and improper disposal pose a serious threat to human health and the environment. The goal of this review paper is to examine the uses and application of pesticides in Myanmar to raise awareness about pesticide misuse and to understand the negative effects of pesticides on human health and the environment. Pesticide misuse is a severe problem in agricultural productivity, putting farmers' health and environment at hazard. Pesticide impacts on the environment have a long-term effect on human life, according to numerous studies, it persists in the environment with long-term negative effects. As a result, pesticide management should be strictly regulated for the whole supply chain process of pesticides.

Agricultural margins could enhance landscape connectivity for pollinating insects across the Central Valley of California, U.S.A.

One of the defining features of the Anthropocene is eroding ecosystem services, decreases in biodiversity, and overall reductions in the abundance of once-common organisms, including many insects that play innumerable roles in natural communities and agricultural systems that support human society. It is now clear that the preservation of insects cannot rely solely on the legal protection of natural areas far removed from the densest areas of human habitation. Instead, a critical challenge moving forward is to intelligently manage areas that include intensively farmed landscapes, such as the Central Valley of California. Here we attempt to meet this challenge with a tool for modeling landscape connectivity for insects (with pollinators in particular in mind) that builds on available information including lethality of pesticides and expert opinion on insect movement. Despite the massive fragmentation of the Central Valley, we find that connectivity is possible, especially utilizing the restoration or improvement of agricultural margins, which (in their summed area) exceed natural areas. Our modeling approach is flexible and can be used to address a wide range of questions regarding both changes in land cover as well as changes in pesticide application rates. Finally, we highlight key steps that could be taken moving forward and the great many knowledge gaps that could be addressed in the field to improve future iterations of our modeling approach.

Intelligent spray technology to control pests in nursery and orchard systems with reduced pesticide application rates

Intelligent spray technology to control pests in nursery and orchard systems with reduced pesticide application rates

Characteristics and influencing factors of chemical fertilizer and pesticide applications by farmers in hilly and mountainous areas of Southwest, China

Studying the characteristics and driving factors of chemical fertilizer and pesticide application of farmers is helpful for the prevention and control of regional non-point source pollution (NPSP). In this study, 320 farmers in Chongqing were surveyed, and the characteristics and main factors influencing chemical fertilizer and pesticide applications were analyzed by spatial analysis and partial least squares regression (PLSR). The results can be showed that: (1) Aaverage unit area applications of N, P2O5 and pesticide were 6.01 kg/ha/yr, 3.78 kg/ha/yr and 107.89 g/ha/yr. Among them, the fertilizer and pesticide application rates of large-scale households are 8.46 kg/ha/yr/, 5.82 kg/ha/yr and 287.61 g/ha/yr, and the application rates of general farmers are 4.54 kg/ha/yr, 2.55 kg/ha/yr and 40.21 g/ha/yr. Larger amount were applied to orchard and vegetable by large-scale farmer, while larger amounts were applied to grain by general farmers. (2) Fertilizer were spatially agglomerated on a household scale, while pesticide were spatially discrete on a county scale. (3) Average age (AA) of farmers and planting scale (PL) are the main factors affecting fertilizer amounts. Education level (EL), policy guidance (PG), and awareness of environmental effects (AEE) are the main factors influencing pesticide applications. Governments need to formulate rural labor policies and promote land transfer, while also strengthening fertilizer and pesticide reduction policies to enhance farmers’ environmental awareness.

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

The use of Bayesian networks (BN) for environmental risk assessment has increased in recent years as they offer a more transparent way to characterize risk and evaluate uncertainty than the traditional risk assessment paradigms. In this study, a novel probabilistic approach applying a BN for risk calculation was further developed and explored by linking the calculation a risk quotient to alternative future scenarios. This extended version of the BN model uses predictions from a process-based pesticide exposure model (World Integrated System for Pesticide Exposure - WISPE) in the exposure characterization and toxicity test data in the effect characterization. The probability distributions for exposure and effect are combined into a risk characterization (i.e. the probability distribution of a risk quotient), a common measure of the exceedance of an environmentally safe exposure threshold. The BN model was used to account for variabilities of the predicted pesticide exposure in agricultural streams, and inter-species variability in sensitivity to the pesticide among freshwater species. In Northern Europe, future climate scenarios typically predict increased temperature and precipitation, which can be expected to cause an increase in weed infestations, plant disease and insect pests. Such climate-related changes in pest pressure in turn can give rise to altered agricultural practices, such as increased pesticide application rates, as an adaptation to climate change. The WISPE model was used to link a set of scenarios consisting of two climate models, three pesticide application scenarios and three periods (year ranges), for a case study in South-East Norway. The model was set up for the case study by specifying environmental factors such as soil properties and field slope together with chemical properties of pesticides to predict the pesticide exposure in streams adjacent to the agricultural fields. The model was parameterized and evaluated for five selected pesticides: the three herbicides clopyralid, fluroxypyr-meptyl, and 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), and the two fungicides prothiocanzole and trifloxystrobin. This approach enabled the calculation and visualization of probability distribution of the risk quotients for the future time horizons 2050 and 2085. The risk posed by the pesticides were in general low for this case study, with highest probability of the risk quotient exceeding 1 for the two herbicides fluroxypyr-meptyl and MCPA. The future climate projections used here resulted in only minor changes in predicted exposure concentrations and thereby future risk. However, a stronger increase in risk was predicted for the scenarios with increased pesticide application, which can represent an adaptation to a future climate with higher pest pressures. In the current study, the specific BN model predictions were constrained by an existing set of climate projections which represented only one IPCC scenario (A1B) and two climate models. Further advancement of the BN modelling demonstrated herein, including more recent climate scenarios and a larger set of climate models, is anticipated to result in more relevant risk characterization also for future climate conditions. This probabilistic approach will have the potential to aid targeted management of ecological risks in support of future research, industry and regulatory needs.

Risk Assessment of Nitrate Pollution in the Shallow Groundwater of the Mihe Alluvial–Diluvial Fan Based on a DEA Model

Affected by excessive fertilizer application and livestock breeding, the problem of nitrate pollution in the groundwater in the Mihe alluvial–diluvial fan area is becoming increasingly prominent, which poses a great threat to human production and life. Given this, the risk of nitrate pollution in the shallow groundwater of the Mihe alluvial–diluvial fan is evaluated by introducing a data envelopment analysis (DEA) method. Using this model, 28 groundwater sampling points are selected as the decision-making unit (DMU); the nitrogen and pesticide application rate, livestock and poultry stock, groundwater burial depth, aquifer water abundance, and vegetable planting area are taken as the model input; and the nitrate content is taken as the model output to quantitatively calculate the pollution risk index to form a spatial distribution map of pollution risk. The calculation using the model shows that the average pollution risk index of the study area is 0.382, the spatial variation is 1.12, the pollution risk index gradually decreases from south to north, and agricultural planting and livestock and poultry breeding are the main pollution sources. The calculation of nitrate pollution risk using this model not only enriches the nitrate pollution evaluation model but also provides a basis for further implementing the action of reducing fertilizer use by increasing its efficiency and strengthening the prevention of agricultural diffused pollution.

Potential Environmental Impacts of Peanut Using Water Footprint Assessment: A Case Study in Georgia

The recent decade has witnessed an increase in irrigated acreage in the southeast United States due to the shift in cropping patterns, climatic conditions, and water availability. Peanut, a major legume crop cultivated in Georgia, Southeast United States, has been a staple food in the American household. Regardless of its significant contribution to the global production of peanuts (fourth largest), studies related to local or regional scale water consumption in peanut production and its significant environmental impacts are scarce. Therefore, the present research contributes to the water footprint of peanut crops in eight counties of Georgia and its potential ecological impacts. The impact categories relative to water consumption (water depletion—green and blue water scarcity) and pesticide use (water degradation—potential freshwater ecotoxicity) using crop-specific characterization factors are estimated for the period 2007 to 2017 at the mid-point level. These impacts are transformed into damages to the area of protection in terms of ecosystem quality at the end-point level. This is the first county-wise quantification of the water footprint and its impact assessment using ISO 14046 framework in the southeast United States. The results suggest inter-county differences in water consumption of crops with higher blue water requirements than green and grey water. According to the water footprint analysis of the peanut crop conducted in this study, additional irrigation is recommended in eight Georgia counties. The mid-point level impact assessment owing to water consumption and pesticide application reveals that the potential freshwater ecotoxicity impacts at the planting and growing stages are higher for chemicals with high characterization factors regardless of lower pesticide application rates. Multiple regression analysis indicates blue water, yield, precipitation, maximum surface temperature, and growing degree days are the potential factors influencing freshwater ecotoxicity impacts. Accordingly, a possible impact pathway of freshwater ecotoxicity connecting the inventory flows and the ecosystem quality is defined. This analysis is helpful in the comparative environmental impact assessments for other major crops in Georgia and aids in water resource management decisions. The results from the study could be of great relevance to the southeast United States, as well as other regions with similar climatic zones and land use patterns. The assessment of water use impacts relative to resource availability can assist farmers in determining the timing and layout of crop planting.

Screening safe pesticide application rates in crop fields for protecting consumer health: A backward model for interim recommended rates.

To reduce human health risks and comply with regulatory standards, it is necessary to provide safe application rates of pesticides in crop fields. In this study, a screening-level model is proposed to improve the regulation of pesticide application rates based on the dynamiCrop platform, which can serve as a complementary approach to field trials for regulatory agencies. The screening-level model can conveniently simulate safe application rates of pesticides based on consumer health risks and maximum residue levels (MRLs). Using 2,4-D as an example, the simulation results agreed with the data of field trials under Good Agricultural Practices and demonstrated that current manufacturers' recommended application rates can effectively comply with MRLs and protect human health. In addition, we simulated the default safe application rates of 449 pesticides in five common crops using the default values of the acceptable daily intake (ADI; 0.01 mg kg-1 day-1 ) and MRL (0.01 mg kg-1 ). The results demonstrated that aerial-fruit crops (e.g., tomatoes and apples) had much lower default safe application rates of pesticides than tuber crops due to the different pesticide uptake mechanisms of plants. In addition, the MRL-based default safe application rates were significantly lower than the ADI-based default rates, indicating that the default MRL of 0.01 mg kg-1 adopted by current regulatory agencies is very conservative regarding population health risks. Although other factors, such as the variability of residue levels in crops, occupational exposure (farmers and operators), and multiple pesticide application patterns, need to be considered in future studies, our screening-level model could be used as a complementary tool in field trials to assist regulatory agencies in regulating pesticide application rates in crop fields. Integr Environ Assess Manag 2023;19:126-138. © 2022 SETAC.