Agriculture Development, Pesticide Application and Its Impact on the Environment

Obregón Alvarez D., Mendes K.F., Tosi M., Fonseca de Souza L., Campos Cedano J.C., de Souza Falcão N.P., Dunfield K., Tsai S.M., Tornisielo V.L.

Sulfometuron-methyl is a broad-spectrum herbicide, used throughout Brazil; however, its environmental impacts in biochar (BC) amended soils is not fully understood. Biochar is known to enhance soil quality but can also have undesired effects such as altering the bioavailability and behavior of herbicides. Microbial communities can degrade herbicides such as sulfometuron-methyl in soils; however, they are known to be affected by BC. Therefore, it is important to understand the tripartite interaction between these factors. This research aimed to evaluate the sorption-desorption and biodegradation of sulfometuron-methyl in Amazonian soils amended with BC, and to assess the effects of the interactions between BC and sulfometuron-methyl on soil bacterial communities. Soil samples were collected from field plots amended with BC at three doses (0, 40 and 80 t ha −1 ) applied ten years ago. The herbicide sorption and desorption were evaluated using a batch equilibrium method. Mineralization and biodegradation studies were conducted in microcosms incubated with 14 C-sulfometuron-methyl for 80 days. Systematic soil sampling, followed by DNA extraction, quantification (qPCR) and 16S rRNA amplicon sequencing were performed. The presence of BC increased the sorption of the herbicide to the soil by 11% (BC40) and 16% (BC80) compared to unamended soil. The presence of BC also affected the degradation of 14 C-sulfometuron-methyl, reducing the mineralization rate and increasing the degradation half-life times (DT50) from 36.67 days in unamended soil to 52.11 and 55.45 days in BC40 and BC80 soils, respectively. The herbicide application altered the bacterial communities, affecting abundance and richness, and changing the taxonomic diversity (i.e., some taxa were promoted and other inhibited). A tripartite interaction was found between BC, the herbicide and soil bacterial communities, suggesting that it is important to consider the environmental impact of soil applied herbicides in biochar amended soils. • The effects of sulfometuron-methyl on soil bacteria were explored in biochar-amended soils. • Biochar addition increased herbicide sorption in soils by more than 10%. • Biochar affected herbicide degradation, increasing half-life from 36 to more than 50 days. • The herbicide reduced bacterial richness, especially in the presence of biochar. • Different taxa were promoted/inhibited by the herbicide, depending on the biochar levels.

Liu J., Zhou J.H., Guo Q.N., Ma L.Y., Yang H.

Atrazine residue in soil is one of the serious environmental problems and continues to risk ecosystem and human health. To address the environmental behaviors and dissipation of atrazine and better manage the application of atrazine in reality, we comprehensively investigated the adsorption and desorption, migration ability, and vanishing of atrazine in three distinct soils in China including Jiangxi (JX, pH 5.45, TOC 0.54%), Nanjing (NJ, pH 6.15, TOC 2.13%), and Yancheng (YC, pH 8.60, TOC 0.58%) soils. The atrazine adsorptive capacity to the soils was arranged in the order of NJ > YC > JX. The leaching assay with profiles of the soils showed strong migration, suggesting it had a high bioavailability to weeds and potential for underground water contamination. We further investigated the effects of environmental factors such as soil moisture, microbial activity and photolysis on atrazine degradation and showed that the degradation of atrazine in the soil mainly underwent the abiotic process, most likely through hydrolysis and photolysis-mediated mechanisms, and to less extend through soil microbial catabolism. Using HRLC-Q-TOF-MS/MS and by comparing the measured and theoretical m/z values and fragmentation data, ten metabolites comprising eight degraded products and two conjugates were characterized. Atrazine existing in the soils and sprayed coordinately blocked the growth of three common weeds, which prompted us to use the minimal atrazine in practice to control the waste of the pesticide and its impact on the environment. Overall, our work provided an insight into the mechanisms for the degradation of atrazine residues in the soils and contributed to the environmental risk assessment of the pesticide and management in its application control in the crop rotation and safe production.

Doan N.H., Duong H.T., Trinh H.T., Tanaka Y., Kadokami K.

Air pollution is the most serious environmental issue in Vietnam, particularly in big cities. Air pollutants that are set as environmental standards are regularly monitored by the public institutions. Whereas, environmental data on organic micro-pollutants in atmospheric particulate matters (APMs) is limited, including PAHs and POPs. Although massive pesticides are used in big cities, their data in APMs in Vietnam is very scarce. In order to elucidate their occurrence in the ambient air in Hanoi and their health effects, we surveyed 107 insecticides in APMs by a novel target screening method using LC-QTOF-MS-SWATH. A total of 19 insecticides were detected in the dry and the rainy seasons. Among them, 16 substances are, to our knowledge, reported for the first time in the literature. Their total concentrations varied from 0.47 to 27.0 ng m-3 (median, 3.6 ng m-3), detection frequencies of 12 compounds are higher than 42%, and the number of insecticides detected per each sample ranging from 5 to 13 (median, 9). Total concentrations in the dry season were generally higher than in the rainy season, and concentrations at night were higher than daytime in both seasons. The level of insecticides depends not only on the season, but also on its physicochemical properties, its application conditions, and the meteorological conditions. Their emission sources could be related to agricultural usage, floricultural activities, and pest control in houses. The total maximum daily intake (DIair) through inhalation for adults and children were 2.39E-05 mg kg-1 d-1 and 2.98E-05 mg kg-1 d-1, respectively. The highest Hazard Quotients (HQs) were 1.34E-03 and 3.37E-03, and the highest Hazard Indices (HIs) were 2.71E-03 and 6.33E-03 for adults and children, respectively. All values of HQs, and HIs of insecticides were less than 1, indicating that health risk would be negligible.

Ou J., Li H., Ou X., Yang Z., Chen M., Liu K., Teng Y., Xing B.

Phenazines, a large group of nitrogen-containing heterocycles with promising bioactivities, can be widely used as medicines and pesticides. But phenazines also generate toxicity risks due to their non-selective DNA binding. The environmental fate of phenazines in soils is the key to assess their risks; however, hitherto, there have been very few related studies. Therefore in the present study, the degradation, adsorption and leaching behaviors of a typical natural phenazine—phenazine-1-carboxamide (PCN) in agricultural soils from three representative places in China with different physicochemical properties were, for the first time, systematically studied in laboratory simulation experiments. Our results indicated that the degradation of PCN in all the tested soils followed the first order kinetics, with half-lives ranging from 14.4 to 57.8 d under different conditions. Soil anaerobic microorganisms, organic matter content and pH conditions are important factors that regulating PCN degradation. The adsorption data of PCN were found to be well fitted using the Freundlich model, with the r 2 values above 0.978. Freundlich adsorption coefficient K f of PCN ranged from 5.75 to 12.8 [(mg/kg)/(mg/L) 1/n ] in soils. The retention factor R f values ranged from 0.0833 to 0.354, which means that the mobility of PCN in the three types of soil is between immobile to moderately mobile. Our results demonstrate that PCN is easily degraded, has high adsorption affinity and low mobility in high organic matter content and clay soils, thus resulting in lower risks of contamination to groundwater systems. In contrast, it degraded slowly, has low adsorption affinity and moderately mobile in soils with low organic matter and clay content, therefore it has higher polluting potential to groundwater systems. Overall, these findings provide useful insights into the future evaluation of environmental as well as health risks of PCN. • This is the first report of the environmental behaviors of phenazine in soils. • Anaerobic microorganisms were more important than the aerobic for degradation of PCN. • PCN easily degraded, has high adsorption and low mobility in high OMC and clay soils. • PCN in high OMC and clay soils has lower contamination risks to groundwater systems. PCN degraded slowly, has low adsorption affinity and moderate mobility in low OMC and clay content soils, therefore has higher polluting potential to groundwater systems.

Bošković N., Brandstätter-Scherr K., Sedláček P., Bílková Z., Bielská L., Hofman J.

Conazole fungicides are currently used pesticides with considerable chronic toxicity and ecotoxicity that are also on EU list for substitution. They enter the soil forming short- or long-term residues. In this study two of their representatives, epoxiconazole (EPC) and tebuconazole (TBC), have been tested with 20 soils from the Czech Republic for their adsorption. Adsorption, by means of Kd coefficients, was compared to “basic” (TOC, pH, clay …) and “advanced” (surface area, minerals ..) soil properties. After doing multivariate analysis of the variables it was apparent that adsorption of both pesticides was highly associated with pH (negatively correlated), and less associated with soil organo-mineral complex (TOC, clay and surface area) and C and N in soil organic matter (OM). Particle sizes or cation exchange capacity (CEC) did not show correlation with adsorption, but showed an association in multidimensional space in factor analysis (FA). Some correlations were revealed between EPC adsorption and soil organic matter parameters. Recalculating Kd to K oc and to Gibb’s free energy (ΔG) and its values indicated that the adsorption of EPC and TBC is mainly weak physical adsorption – partitioning. Also, ΔG values gave better correlation with pH (H2O) than Kd. Surface area impacted EPC adsorption. From the several soil minerals, kaolinite showed EPC and TBC adsorption. EPC adsorption was not highly influenced with pH changes compared to TBC. The number and types of H-bonds with molecular geometry govern the sorption, which might crucially affect leachibility in soil, and this may indicate that TBC is more leachable than EPC for the same soil. • Kd values of EPC and TBC from 20 different soils in the Czech Republic were determined. • Adorption mostly correlated with pH(H2O). • Fungicide ΔG gives better statistical correlation with soil pH than Kd. • Type of H bonding influences adsorption.

Pan D., He M., Kong F.

Understanding farmers’ pesticide application behaviors is essential for environmental sustainability and food safety in China. Based on a nationally representative survey of 603 rice farmers from seven major rice-producing provinces in China, this paper constructs a moderation and mediation model to examine the causal relationship between risk attitudes, risk perceptions, and farmers’ pesticide application behaviors. The results show that risk-averse farmers are more likely to use more pesticides. Farmers’ perceptions of the risks posed by pesticides to profit-maximizing factors, namely food quality and human health, can decrease their pesticide expenditure, while their perceptions of risks to environmental factors, namely soil degradation, water pollution, and air pollution, are not significantly associated with their pesticide expenditure. Moreover, their perceptions of risks to food quality and human health can alleviate the positive effect of risk attitude on pesticide expenditure, and can also play a partial mediating role in the relationship between risk attitude and pesticide expenditure. Risk management tools such as crop insurance, and educational programs to improve farmers’ risk perception, would be beneficial policies to help alleviate farmers’ excessive pesticide use.

Farhan M., Wajid A., Hussain T., Jabeen F., Ishaque U., Iftikhar M., Daim M.A., Noureen A.

Chlorpyrifos (ChF) is an organophosphate pesticide that is widely used in agricultural fields and indoor for controlling pests. Aquatic ecosystems are the recipients of various pesticide residues due to leaching spray drift and agricultural runoff and pose toxicity for aquatic organisms. Therefore, the current study was designed to investigate the oxidative stress enzymes and histological alterations in the vital organs of tilapia due to ChF exposure. LC50 (24 h) was calculated as 52.78 μg/l by exposing tilapia with different acute concentrations of ChF. For assessment of sub-lethal toxicity of ChF, the fish were divided into four groups (ChF1, ChF2, ChF3, and control group). ChF1 group was treated with 1/15th of LC50, whereas ChF2 and ChF3 groups were treated with 1/10th and 1/5th of LC50, respectively for 14 days. After that, ChF induced changes in oxidative stress enzymes and histological alterations were evaluated. It was found that the level of glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) increased significantly in the liver of ChF-treated tilapia. Histological study of liver tissues showed an increased number of Kupffer cells, hydropic degeneration, necrosis, and hemorrhage. In the spleen of treated fish, increased melanomacrophage centers, necrosis, and congestion were detected. Disorganized muscle fibers, cardiac muscle fiber degeneration, and coagulative necrosis were observed in the heart of ChF-treated fish. It is concluded that sub-lethal concentrations of ChF can induce oxidative stress and histological alterations in the tissues of tilapia.

Grella M., Miranda-Fuentes A., Marucco P., Balsari P., Gioelli F.

Pneumatic spraying is especially sensitive to spray drift due to the production of small droplets that can be easily blown away from the treated field by the wind. Two prototypes of environmentally friendly pneumatic spouts were developed. The present work aims to check the effect of the spout modifications on the spray quality, to test the convenience of setting the liquid hose out of the spout in cannon-type and hand-type pneumatic nozzles and its effect on the droplet size, homogeneity and driftability in laboratory conditions. Laboratory trials simulating a real sprayer were conducted to test the influence of the hose insertion position (HP), including conventional (CP), alternative (AP), outer (OP) and extreme (XP), as well as the liquid flow rate (LFR) and the airflow speed (AS) on the droplet size (D50, D10 and D90), homogeneity and driftability (V100). Concurrently, the droplet size spectra obtained by the combination of aforementioned parameters (HP × LFR × AS) in both nozzles were also classified according to the ASABE S572.1. Results showed a marked reduction of AS outside the air spout, which led to droplet size increase. This hypothesis was confirmed by the droplet size spectra measured (D50, D10, D90 and V100). A clear influence of HP was found on every dependent variable, including those related with the droplet size. In both nozzles, the longer the distance to CP, the coarser the sprayed drops. Moreover, LFR and AS significantly increased and reduced droplet size, respectively. A higher heterogeneity in the generated drops was obtained in XP. This position yielded V100 values similar to those of the hydraulic low-drift nozzles, showing an effective drift reduction potential. The classification underlines that the variation of HP, alongside AS and LFR, allowed varying the spray quality from very fine to coarse/very coarse, providing farmers with a wide range of options to match the drift-reducing environmental requirements and the treatment specifications for every spray application.

Benka-Coker W., Hoskovec L., Severson R., Balmes J., Wilson A., Magzamen S.

Ambient environmental pollutants have been shown to adversely affect respiratory health in susceptible populations. However, the role of simultaneous exposure to multiple diverse environmental pollutants is poorly understood.We applied a multidomain, multipollutant approach to assess the association between pediatric lung function measures and selected ambient air pollutants and pesticides.Using data from the US EPA and California Pesticide Use Registry, we reconstructed three months prior exposure to ambient air pollutants ((ozone (O3), nitrogen dioxide (NO2), particulate matter with a median aerodynamic diameter < 2.5 μm (PM2.5) and

Pourreza A., Moghimi A., Niederholzer F.J., Larbi P.A., Zuniga-Ramirez G., Cheung K.H., Khorsandi F.

Unmanaged spray drift from orchard pesticide application contributes to environmental contamination and causes significant danger to farmworkers, nearby residential areas, and neighbors’ crops. Most drift control approaches do not guarantee adequate and uniform canopy spray coverage. Our goal was to develop a spray backstop system that could block drifting from the top without any negative impact on spray coverage and on-target deposition. The design included a foldable mast and a shade structure that covered the trees from the top. We used a continuous loop sampling to assess and quantify the effectiveness of spray backstop on drift potential reduction. We also collected leaf samples from different sections of trees to compare on-target deposition and coverage. The results showed that the spray backstop system could significantly (p-Value < 0.01) reduce drift potential from the top (78% on average). While we did not find any statistical difference in overall canopy deposition with and without the backstop system, we observed some improvement in treetops deposition. This experiment’s output suggests that growers may be able to adjust their air-assist sprayers for a more uniform spray coverage without concern about the off-target movement of spray droplets when they employ the spray backstop system.

Van Steenwyk R.A., Siegel J.P., Bisabri B., Cabuslay C.S., Choi J.M., Steggall J.W., Mace K.C., Blecker S.W., Poe P.A., Peters‐Collaer S.R., Klassen P.

BACKGROUND Pesticide drift is a serious environmental and safety concern that affects all of US agriculture. A number of mitigation techniques to reduce pesticide drift have been recommended by industry, academic and government agencies. These techniques are very costly or reduce the efficacy of the pest control product and have not been implemented by US agriculture. RESULTS When using a novel spray technique (Air-in), pesticide drift was significantly reduced by between 53% and 99% at 7.6 m from the orchard drip line when compared to the grower standard. This technique not only reduced pesticide drift, but also maintained or improved the amount of pesticide residue deposited (by 0.7-2.6-fold) and the percentage pesticide coverage (by 1.0-1.4-fold) with different air-blast speed sprayers on almond, walnut and pistachio. CONCLUSION The Air-in technique shows great promise in reducing pesticide drift while maintaining or improving pesticide coverage with minimal cost to the grower.

Wang G., Han Y., Li X., Andaloro J., Chen P., Hoffmann W.C., Han X., Chen S., Lan Y.

Unmanned Aerial Vehicle (UAV) applications at low-volume using fine and very fine size droplets have been adopted in several commercial spray scenarios allowing water-saving and high-efficiency operation in delivery of pesticides. However, spray drift associated with UAV applications, especially for fine droplets generated from spinning disk nozzles, has not been fully understood, raising environmental and regulatory concerns. The objectives of this study were to compare the drift potential of three different volume median diameter (VMD, or Dv0.5) of 100, 150 and 200 μm from a commercial quadcopter equipped with centrifugal nozzles exposed to different wind speeds under field conditions. Prior to field test, the droplet size of the centrifugal nozzle was measured by a laser-diffraction particle-size analyzer. The results showed that the relationship between rotation speed and Dv0.5 agrees with the negative power function. Field tests found that the deposition at 12 m downwind direction decreased by an order of magnitude compared with the average deposition within the in-swath zone. The deposition of almost all the treatments at 50 m downwind is lower than the detection limits of 0.0002 μL/cm2. Based on the results from this study, the drift distance of this specific very popular UAV model is much less than that of manned aerial applicators. Based on the predicted equation (R2 = 0.83), the detected drift amount increased with increasing wind speed and decreasing Dv0.5. This work provides basic information to quantify the effect of wind speeds and droplet sizes on UAV spray drift potential which supports on-going regulatory guideline development for spray buffer zone and drift risk assessment protocols.

Zhang H., Qi L., Wu Y., Musiu E.M., Cheng Z., Wang P.

Rotor unmanned aerial vehicles (UAVs) for pesticide spraying have been widely used in China during the past three years. In order to improve the effectiveness of pesticide application and reduce environmental risk caused by spray drift, it is important to clarify the spatiotemporal distribution characteristics of airflow field of the drone. The airflow field produced by the UAV plays a key role in droplets delivery during the spraying. In this study, the lattice Boltzmann method (LBM) based on a mesoscopic kinetic model was used to simulate the airflow field of a six–rotor plant protection drone. The airflow field of drone in hover and at varied flight speeds (1.0–5.0 m s−1) and various altitudes (1.5–3.5 m) was investigated. The characteristics of airflow separation, airflow coverage equivalent area and “steep” effect were investigated numerically. The peak value of vertical downward velocity (V–Y) on the detection surface was analysed. Results indicate that the flight speed and altitude had a significant effect on the distribution of the airflow field. The predicted values in the vertical direction using the average velocity attenuation model (Y–DAVA) corresponded well with experimental measurements. The wake of airflow field had a significant backward tilt when the drone was flying forwards, thus when the flight speed was 4.0 m s−1 and 5.0 m s−1, the wake of the airflow field lifted off the ground, whereas the transverse separation appeared as horseshoe vortices. For flight speeds of 3.0 m s−1 and an altitude of 3.0 m the distribution of V–Y was the most uniform.

Ghaste M., Hayden N.C., Osterholt M.J., Young J., Young B., Widhalm J.R.

Dicamba is a moderately volatile herbicide used for post-emergent control of broadleaf weeds in corn, soybean, and a number of other crops. With increased use of dicamba due to the release of dicamba-resistant cotton and soybean varieties, growing controversy over the effects of spray drift and volatilization on non-target crops has increased the need for quantifying dicamba collected from water and air sampling. Therefore, this study was designed to evaluate stable isotope-based direct quantification of dicamba from air and water samples using single-quadrupole liquid chromatography–mass spectrometry (LC–MS). The sample preparation protocols developed in this study utilize a simple solid-phase extraction (SPE) protocol for water samples and a single-step concentration protocol for air samples. The LC–MS detection method achieves sensitive detection of dicamba based on selected ion monitoring (SIM) of precursor and fragment ions and relies on the use of an isotopically labeled internal standard (IS) (D3-dicamba), which allows for calculating recoveries and quantification using a relative response factor (RRF). Analyte recoveries of 106–128% from water and 88–124% from air were attained, with limits of detection (LODs) of 0.1 ng mL−1 and 1 ng mL−1, respectively. The LC–MS detection method does not require sample pretreatment such as ion-pairing or derivatization to achieve sensitivity. Moreover, this study reveals matrix effects associated with sorbent resin used in air sample collection and demonstrates how the use of an isotopically labeled IS with RRF-based analysis can account for ion suppression. The LC–MS method is easily transferrable and offers a robust alternative to methods relying on more expensive tandem LC–MS/MS-based options.

Grella M., Marucco P., Balafoutis A.T., Balsari P.

The most widespread method for weed control and suckering in vineyards is under-row band herbicide application. It could be performed for weed control only (WC) or weed control and suckering (WSC) simultaneously. During herbicide application, spray drift is one of the most important environmental issues. The objective of this experimental work was to evaluate the performance of specific Spray Drift Reducing Techniques (SDRTs) used either for WC or WSC spray applications. Furthermore, spray drift reduction achieved by buffer zone adoption was investigated. All spray drift measurements were conducted according to ISO22866:2005 protocol. Sixteen configurations deriving from four nozzle types (two conventional and two air-induction—AI) combined with or without a semi-shielded boom at two different heights (0.25 m for WC and 0.50 m for WSC) were tested. A fully-shielded boom was also tested in combination with conventional nozzles at 0.25 m height for WC. Ground spray drift profiles were obtained, from which corresponding Drift Values (DVs) were calculated. Then, the related drift reduction was calculated based on ISO22369-1:2006. It was revealed that WC spray applications generate lower spray drift than WSC applications. In all cases, using AI nozzles and semi-shielded boom significantly reduced DVs; the optimum combination of SDRTs decreased spray drift by up to 78% and 95% for WC and WSC spray application, respectively. The fully-shielded boom allowed reducing nearly 100% of spray drift generation. Finally, the adoption of a cropped buffer zone that includes the two outermost vineyard rows lowered the total spray drift up to 97%. The first 90th percentile model for the spray drift generated during herbicide application in vineyards was also obtained.

Reghais A., Drouiche A., Zahi F., Ewuzie U., Debieche T., Drias T.

Liu J., Zhao Y., Cheng L., Lu Z., Liang H., Zhu R., Wang Y., Deng F., Ni Z., Li Y., Yu G., Zhang J., Zhu Y., Qiu R.

Habibullah-Al-Mamun M., Sakib S., Das R., Faruque M.H., El-Gendy A.H., Almansour M.I., Alfarraj S.

Leguizamón Y., Goldenberg M.G., Jobbágy E., Whitworth-Hulse J.I., Satorre E., Paolini M., Martini G., Micheloud J.R., Garibaldi L.A.

Fei-Baffoe B., Gawu E., Yahans Amuah E.E., Sangber-Dery A., Adjiri Sackey L.N., Douti N.B.

Wei D., Zhang X., Guo Y., Saleem K., Jia J., Li M., Yu H., Hu Y., Yao X., Wang Y., Chang X., Song C.

He P., Zheng S., Li Y., Guo H., Yang F.

Damiani G., Dell’Omo G., Costantini D.

Restivo M.D., Silva do Nascimento D., Sepúlveda Y., Etcheverry M., Waiman C.V., Zanini G.P.

Yang X., Zhang F., Wang J., Tian C., Meng X.

Omrani M., Mohammadi M., Ghasemi M., Sadeghi H.

Feng H., Deng D., Zhu F., Chen S., Geng J., Jiang S., Zhang K., Jiang J., Yin S., Zhang C.

Angelis P.N., Rocha L.R., Prete M.C., Medeiros R.A., da Silva Araujo M., Pereira A.C., Borsato D., Segatelli M.G., Tarley C.R.

Song P., Lei D., Li L., Long N., Xu Q., Li Y., Zhou L., Pan R., Kong W.

Shahbazi F., Shahbazi S., Nadimi M., Paliwal J.