Agrochemical Residues Research Articles

Plasmonic Nanostructures Grown from Reacting Droplet-In-Microwell Array on Flexible Films for Quantitative Surface-Enhanced Raman Spectroscopy in Plant Wearable In Situ Detection.

Plant wearable detection has garnered significant interest in advancing agricultural intelligence and promoting sustainable food production amidst the challenges of climate change. Accurately monitoring plant health and agrochemical residue levels necessitates qualities such as precision, affordability, simplicity, and noninvasiveness. Here, a novel attachable plasmonic film is introduced and designed for on-site detection of agrochemical residues utilizing surface-enhanced Raman spectroscopy (SERS). By functionalizing a thin polydimethylsiloxane film with silver nanoparticles via controlled droplet reactions in micro-well arrays, a plasmonic film is achieved that not only maintains optical transparency for precise analyte localization but also conforms closely to the plant surface, facilitating highly sensitive SERS measurements. The reliability of this film enables accurate identification and quantification of individual compounds and their mixtures, boasting an ultra-low detection limit ranging from 10-16 to 10-13 m, with mini mal relative standard deviation. To showcase its potential, on-field detection of pesticide residues on fruit surfaces is conducted using a handheld Raman spectrometer. This advancement in fabricating plasmonic nanostructures on flexible films holds promise for expanding SERS applications beyond plant monitoring, including personalized health monitoring, point-of-care diagnosis, wearable devices for human-machine interface, and on-site monitoring of environmentalpollutants.

Climatic fluctuations alter the preference of stingless bees (Apidae, Meliponini) towards food contaminated with acephate and glyphosate

The global decline of pollinators has become a major concern for the scientific community, policymakers, and the general public. Among the main drivers of diminishing bee populations is the widespread use of agrochemicals. To gain a comprehensive understanding of the foraging dynamics of bees at agrochemical-contaminated areas, it is essential to consider both environmental conditions and the specific foraging ecology of bee species. For the first time, we conducted a semi-field study to investigate whether stingless bees exhibit a preference for food contaminated with agrochemicals compared to non- contaminated food, under natural weather conditions. Colonies of Plebeia lucii Moure, 2004 were placed in a greenhouse and subjected to a preference test, where bees were given the freedom to choose between contaminated or non-contaminated food sources following a preliminary training period. Within the greenhouse, we placed feeders containing realistic concentrations of an insecticide (acephate: 2 mg a.i./L), a herbicide (glyphosate: 31.3 mg a.i./L), or a mixture of both, alongside non-contaminated food. Environmental variables (temperature, humidity, and light intensity) were monitored throughout the experiment. At higher temperatures, the foragers preferred food containing the mixture of both agrochemicals or uncontaminated food over the other treatments. At lower temperatures, by contrast, the bees preferred food laced with a single agrochemical (acephate or glyphosate) over uncontaminated food or the agrochemical mixture. Our findings indicate that agrochemical residues in nectar pose a significant threat to P. lucii colonies, as foragers do not actively avoid contaminated food, despite the detrimental effects of acephate and glyphosate on bees. Furthermore, we demonstrate that even minor, natural fluctuations in environmental conditions can alter the colony exposure risk. Despite the interplay between temperature and bees' preference for contaminated food, foragers consistently collected contaminated food containing both agrochemicals, whether isolated or in combination, throughout the whole experiment.

Facile fabrication of bismuth oxide anchored graphene oxide for the effective electrochemical sensing of diuron

BackgroundDiuron (DU), a weed controller widely used in the agricultural industry, prolonged conception of this agrochemical residue contaminated with environmental water bodies and soil sources could cause an acute impact on the human health system. This work utilized the electrochemical determination technique due to their rapid detection, outstanding sensitivity, and economical purpose. MethodsThe electrochemical behavior of DU at the γ-Bi2O3 microplates interconnected with sheet-like graphene oxide (GO) as a surface-modified electrode was scrutinized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The surface-modified γ-Bi2O3/GO/GCE elucidates superior electrocatalytic performance towards the irreversible oxidation response of diuron than the other surface-modified electrode in the phosphate buffer solution of 0.1 M. Significant findingsThe γ-Bi2O3/GO/GCE electrode displayed an extensive detection range of 0.1–631 µM with a 0.751 µM lower detection limit furthermore, noticeable 0.0280 µA µM-1 cm-2 sensitivity for diuron determination. In addition, the DPV experiment exposed that the γ-Bi2O3/GO/GCE electrode achieves stupendous selectivity, durability, and acceptable feasibility of the real-time samples.

Discrimination of Fungicide-Contaminated Lettuces Based on Maximum Residue Limits Using Spectroscopy and Chemometrics

The fast and effective monitoring of agrochemical residues is essential for assuring food safety, since many agricultural products are sprayed with pesticides and commercialised without waiting for the pre-harvest interval. In this study, we investigated the use of spectral reflectance combined with principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) to evaluate the discrimination of fungicide-contaminated lettuces, considering three maximum residue limits (MRLs) [3.5, 5, and 7 mg carbon disulphide (CS2) kg−1]. The non-systemic Mancozeb fungicide (dithiocarbamate) was adopted in this research. Spectral reflectance (Vis/NIR) was measured by a hand-held spectrometer connected to a clip probe with an integrating sphere. The lettuce spectra were pre-treated (centring, standard normal variate, and first derivative) before data processing. Our findings suggest that PCA recognised inherent similarities in the fungicide-contaminated lettuce spectra, categorising them into two distinct groups. The PLS-DA models for all MRLs resulted in high accuracy levels, with correct discriminations ranging from 94.5 to 100% for the external validation dataset. Overall, our study demonstrates that spectroscopy combined with discriminating methods is a promising tool for non-destructive and fast discrimination of fungicide-contaminated lettuces. This methodology can be used in industrial food processing, enabling large-scale individual analysis and real-time decision making.

Effect of Potassium Schoenite (Mahalaabh) on Growth and Yield of Castor, Cotton and Groundnut

The need for precise nutrient application has become crucial in agriculture due to climate change and intensive farming practices. Deficiencies in potassium, magnesium and sulphur are critical for enhancing both crop yield and quality. Additionally, agrochemical residues in soil, water and farm products pose significant challenges. Mahalaabh (K2SO4·MgSO4·6H2O), a combination of potassium, sulphur and magnesium, offers a balanced solution to address these issues. Field experiments were conducted during the Kharif season of 2023-24 at Agrocel Industries Pvt. Ltd., Kachchh, to evaluate the impact of Mahalaabh on castor, cotton and groundnut crops. The trials were executed in a Randomized Block Design, testing different doses of Mahalaabh powder through foliar spray, fertigation and granular soil application. The results demonstrated that Mahalaabh powder is effective in enhancing productivity across the tested crops. In castor, higher doses of 10 kg/acre through drip irrigation and 20g/L foliar application increased productivity by 22.3% and 14.3% over the recommended fertilizer dose (RFD), respectively. However, in cotton, lower doses of 6kg/acre through drip irrigation and 10g/L through foliar application were more effective, resulting in 3.8% and 5.3% yield enhancements compared to RFD. In groundnut, foliar spray at 15 g/L applied thrice at 30-35, 50-55, and 70-75 days after sowing (DAS) was effective, resulting in a 22.9% higher pod yield compared to RFD. These findings highlight the importance of balanced nutrient management practices tailored to specific crop requirements for achieving optimal agricultural productivity.

Residues of agrochemicals in beebread as an indicator of landscape management

The agricultural intensification represents a major threat to biodiversity, with negative effects on the ecosystem. In particular, habitat loss and degradation, along with pesticide use have been recognised as primary factors contributing to the actual global decline of pollinators. Here we investigated the quality of agroecosystems in the Emilia-Romagna region (Northern Italy) within the national monitoring project BeeNet. We analysed pesticide residues in 100 samples of beebread collected in 25 BeeNet stations in March and June 2021 and 2022. We evaluated diversity and concentration of these chemicals, their risk (TWC) to honey bees, and their correlation with land use. Overall, in 84 % of the samples we found 63 out of 373 different pesticide residues, >90 % of them belonging to fungicides and insecticides. The TWC exceeded the risk threshold in seven samples (TWCmix), mostly due to only one or two compounds. We also found 15 compounds not approved in the EU as plant protection products (PPPs), raising concerns about illegal use or contamination through beeswax recycling. Samples collected in 2021 and in June presented a significantly higher number of active ingredients and TWC than those collected in 2022 and in March. The TWC calculated on single compounds (TWCcom) exceeded the risk threshold in case of four insecticides, namely carbaryl, fipronil, imidacloprid and thiamethoxam (although each detected in only one sample). Finally, both TWC and number of active ingredients were moderately or highly positively correlated with the percentage of area covered by orchards. Considering that we found on average more than five different molecules per sample, and that we ignored potential synergistic effects, the results of this work highlight the alarming situation regarding pesticide treatments and toxicity risk for bees linked to the current agricultural practices, and the need for implementing sustainable and pollinator-friendly strategies.

Sorption and mobility assessment of tembotrione in soils of upper, trans and middle Gangetic plain zones of India.

The presence of undesired agrochemicals residues in soil and water poses risks to both human health and the environment. The behavior of pesticides in soil depends both on the physico-chemical properties of pesticides and soil type. This study examined the adsorption-desorption and leaching behavior of the maize herbicide tembotrione in soils of the upper (UGPZ), trans (TGPZ) and middle Gangetic plain zones of India. Soil samples were extracted using acetone followed by partitioning with dichloromethane, whereas liquid-liquid extraction using dichloromethane was used for aqueous samples. Residues of tembotrione and its metabolite TCMBA, {2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy) methyl] benzoic acid}, were quantified using liquid chromatography-tandem mass spectrometry. The data revealed that tembotrione adsorption decreased with increasing pH and dissolved organic matter but increased with salinity. The maximum adsorption occurred at pH4, 0.01m sodium citrate and 4g/L NaCl, with corresponding Freundlich constants of 1.83, 2.28 and 3.32, respectively. The hysteresis index <1 indicated faster adsorption than desorption. Leaching studies under different flow conditions revealed least mobility in UGPZ soil and high mobility in TGPZ soil, consistent with groundwater ubiquity scores of 4.27 and 4.81, respectively. Soil amendments decreased tembotrione mobility in the order: unamended > wheat straw ash > wheat straw > farm yard manure > compost. The transformation of tembotrione to TCMBA and its mobility in soil columns were also assessed.

Ecological and human health risk of heavy metals in Nubui River: a case of rural remote communities

IntroductionThe Nubui River is a primary source of water for drinking purposes and other domestic activities in the rural communities dotted along its riparian zone, with agriculture being the major activity occurring in this important ecotone. The river has become a potential sink for agrochemical residue, including heavy metals, and has apparent aesthetic water quality issues, with associated health consequences. This study, therefore, assessed the health risks of heavy metals within the rural populations in the catchment areas, who have limited sources of improved water supply.MethodsThe concentration of iron (Fe), lead (Pb), cadmium (Cd), mercury (Hg), and zinc (Zn) was assessed on cumulatively 275 water samples, using a Perkin Elmer PINAAcle 900 T atomic absorption spectrophotometer for 11 months. A cross-sectional survey was conducted amongst 338 community members, following field observations on utilisation types, aesthetic appeal, and perceived quality of water from the Nubui River. To determine the potential human and ecological risks of heavy metals, the hazard quotient, chronic daily intake, contamination factor, and health pollution indices of heavy metals were computed. STATA version 16 was used to analyse the survey results.ResultsDescriptive statistics of average concentrations of heavy metals in surface water at all sampling stations showed the pattern Hg &amp;lt; Pb &amp;lt; Cd &amp;lt; Zn &amp;lt; Fe, with relatively low concentrations, between 0.001 and 0.004 mg/L for Hg, 0.0011 and 0.0019 mg/L for Pb, 0.0461 and 0.0739 mg/L for Zn, and 0.2409 and 0.377 mg/L for Fe. The findings, however, showed relatively high cadmium levels between 0.0215 mg/L and 0.0383 mg/L in two of five sampling stations in comparison with the World Health Organisation (WHO) drinking water guideline values in some months. Hazard quotient values indicate that the population is safe from the non-carcinogenic health risks of exposure to heavy metals through oral routes. The contamination factor and heavy metal pollution indices for cadmium exceed recommended guideline values of 1 and 100, respectively. Meanwhile, 73.1% of community members evidently preferred the Nubui River for various domestic activities with 86.1% of them utilising it for drinking purposes. This occurrence results in exposure to associated health risks.

Core Soil Microorganisms and Abiotic Properties as Key Mechanisms of Complementary Nanoscale Zerovalent Iron and Nitrification Inhibitors in Decreasing Paclobutrazol Residues and Nitrous Oxide Emissions.

Agrochemical residues and nitrous oxide (N2O) emissions have caused considerable threats to agricultural soil ecology. Nanoscale zerovalent iron (nZVI) and nitrification inhibitors might be complementary to each other to diminish soil agrochemical residues and N2O emissions and enhance soil bacterial community diversities. Compared to the control, the nZVI application declined soil paclobutrazol residues by 5.9% but also decreased the bacterial community co-occurrence network node. Combined nZVI and Dicyandiamide applications significantly decreased soil N2O emission rates and paclobutrazol residues but promoted Shannon diversity of the bacterial community. The increased soil pH, ammonium nitrogen, and Actinobacteriota could promote soil paclobutrazol dissipation. The nZVI generated double-edged sword effects of positively decreasing paclobutrazol residues and N2O emissions but negatively influencing soil multifunctionalities. The nZVI and Dicyandiamide could be complementary to each other in diminishing soil agrochemical residues and N2O emission rates but promoting soil bacterial community diversities simultaneously.

Assessing the Impact of Agrochemical Misuse on Health and Environment: A Case Study of Ghanaian Agriculture

The escalating global population demands heightened food production, prompting intensified agricultural practices worldwide. However, this surge in agricultural activity, particularly in underdeveloped regions like Ghana, often leads to the indiscriminate and excessive use of agrochemicals. This study delves into the ramifications of agrochemical misuse on human health and the environment, focusing on Ghana's agricultural sector. Through an examination of scientific evidence and empirical data, the study highlights the prevalence of agrochemical residues in food products and their association with various health conditions. Additionally, it scrutinizes the ecological consequences of agrochemical pollution, emphasizing the need for sustainable farming practices. By assessing the challenges posed by agrochemical misuse, this research advocates for the adoption of organic farming as a viable solution for achieving agricultural sustainability and safeguarding human and environmental well-being. Keywords: Agrochemicals, Agriculture, Health, Environment, Ghana, Pesticides, Organic farming, Sustainable agriculture

Response of duckweed to different irrigation modes under different fertilizer types and rice varieties: Unlocking the potential of duckweed (Lemna minor L.) in rice cultivation as "fertilizer capacitors"

Duckweed (Lemna minor L.) is a common plant in paddy fields, absorbing nutrients, heavy metals, and agrochemical residues from irrigation water, thus playing a pivotal role in ecosystem sustainability. To reveal the combined effects of irrigation modes, rice cultivars, and fertilizer types on duckweed, tank experiments were conducted in two rice-growing seasons (2019 and 2020) in Jiangsu Province, China. The experiment included three factors, each consisting of two levels: rice cultivars (R) (japonica rice (J) and indica rice (X)), fertilizer types (F) (organic fertilizer (O) and chemical fertilizer (C)), and irrigation modes (I) (controlled irrigation (1) and shallow-frequent irrigation (2)). Results indicated that organic fertilizer significantly increased the total phosphorus concentration by 396% and promoted DCR by 703% in floodwater as compared with chemical fertilizer. The significantly higher tiller numbers of indica rice increased the shade level, repressing maximum electron transfer rate (ETRmax) of duckweed, and consequently reduced DCR by 32.8% as compared with japonica rice. A cyclic pattern of Production-Death-Reproduction of duckweed under controlled irrigation was observed, which depended on the periodic cycle of Appear-Disappear-Reappear of the floodwater. Setting the irrigation lower limit to 87.9% saturation water content(θs) can benefit the regeneration of duckweed after re-watering. Similar to a capacitor that could store and release electric charge in circuit system by regulating voltage, under the application of organic fertilizer (battery), duckweed (capacitors) efficiently absorbs, decomposes, and subsequently reabsorbs nutrients by the regulation of controlled irrigation (switch), releasing fertility gradually for the rice plant (electrical appliance).

The Interaction of Pesticides with Humin Fractions and Their Potential Impact on Non-Extractable Residue Formation.

The constant influx of pesticides into soils is a key environmental issue in terms of their potential retention in the soil, thus reducing their negative impact on the environment. Soil organic matter (SOM) is an important factor influencing the environmental fate of these substances. Therefore, the aim of this research was to assess the chemical behavior of pesticides (flufenacet, pendimethalin, α-cypermethrin, metazachlor, acetamiprid) toward stable soil humin fractions (HNs) as a main factor affecting the formation of non-extractable residues of agrochemicals in soil. This research was conducted as a batch experiment according to OECD Guideline 106. For this purpose, HNs were isolated from eight soils with different physicochemical properties (clay content = 16-47%, pHKCl = 5.6-7.7, TOC = 13.3-49.7 g·kg-1, TN = 1.06-2.90 g·kg-1, TOC/TN = 11.4-13.7) to reflect the various processes of their formation. The extraction was carried out through the sequential separation of humic acids with 0.1 M NaOH, and then the digestion of the remaining mineral fraction with 10% HF/HCl. The pesticide concentrations were detected using GC-MS/MS. The pesticides were characterized based on the different sorption rates to HNs, according to the overall trend: metazachlor (95% of absorbed compound) > acetamiprid (94% of absorbed compound) > cypermethrin (63% of partitioning compound) > flufenacet (39% of partitioning compound) > pendimethalin (28% of partitioning compound). Cypermethrin and metazachlor exhibited the highest saturation dynamic, while the other agrochemicals were much more slowly attracted by the HNs. The obtained sorption kinetic data were congruous to the pseudo-first-order and pseudo-second-order models related to the surface adsorption and interparticle diffusion isotherm. The conducted research showed that the processes of pesticide sorption, apart from physicochemical phenomena, are also affected by the properties of the pollutants themselves (polarity, KOC) and the soil properties (SOM content, clay content, and pHKCl).

Pollution of Water Resources by Agrochemicals in the Agroindustrial Areas at the South Western Flank of Mount Cameroon

This study aimed to assess the contribution of certain constituents of soluble agrochemical residues to surface and groundwater pollution in the study area. The constituents studied included Dissolved Oxygen (DO), Nitrate (NO3 - ), Phosphate (PO4 2-), Cadmium (Cd), Lead (Pb), and Nickel (Ni) in various water sources. Forty water samples were collected from both surface and groundwater. In-situ electronic meter measurements were used to determine the DO levels. The laboratory methods of Nitrogen Distillation and spectrophotometry were employed to measure the concentrations of NO3 - and PO4 2-, respectively. The concentrations of heavy metals were determined using Atomic Absorption Spectrometry. The results obtained during the wet season indicated that DO, NO3 - , and PO4 2- levels were within permissible limits. However, for Cd, Pb, and Ni, a significant proportion of values exceeded the permissible limits during this season (Cd: 95%, Pb: 95%, Ni: 35%), suggesting possible contamination of the water sources. Conversely, during the dry season, all parameters were within permissible limits, except for Pb, where 95% of its values exceeded the limit. These findings conclude that the application of agrochemicals in the agro-industrial areas has a notable impact on water resources, particularly during the wet season.

Pre-Harvest Bagging of Table Grapes Reduces Accumulations of Agrochemical Residues and Increases Fruit Quality

Pre-Harvest Bagging of Table Grapes Reduces Accumulations of Agrochemical Residues and Increases Fruit Quality

An Overview of Impact of Agrochemicals on Human Health and Natural Environment

Agrochemicals exposure periods and levels, types of agrochemicals used and various environmental condition of the areas are factors for acute and chronic poisoning on human health and environment. Although agrochemicals are the result of modern technology that depends on inorganic fertilizers and pesticides, their continuous use against agricultural pest and disease vectors poses serious threats upon both human health and environment. Overuse of these chemicals have severe effects on human and environment that may lead to immediate and long-term effects. In developing countries, it is very difficult to find out the impact on the environment due to lack of awareness, training, and adequate knowledge for using agrochemicals. Investigating farmer’s awareness of agrochemicals residues and their behaviors regarding application is important in order to reduce human factors that negatively affect environmental safety. This review focuses on a summary of both national and international studies regarding the impact of pesticide and chemical fertilizer residues on nature, both human and environment. The review has revealed the hazardous effects like cancer, neural disorders, and other health related problems and environmental risks associated with agrochemicals exposure.

Land Resources in Organic Agriculture: Trends and Challenges in the Twenty-First Century from Global to Croatian Contexts

Organic agriculture (OA) is a continuously growing global concept that emphasizes the use of sustainable and environmentally-friendly practices. By adopting OA, it is possible to improve ecosystems services, increase biodiversity, decrease environmental pollution, reduce carbon footprints and mitigate greenhouse gas emissions, generating food that is free from harmful residues of agrochemicals, thereby enhancing food safety and security. This study provides a comprehensive review of the latest insights on the global utilization of land resources in OA, focusing particularly on some EU countries that experienced a notable and rapid progress in organic farming during the past two decades. With negligible 1.6% (75 Mha) of global cropland is currently dedicated to OA, there is ample opportunity to expand the adoption of OA and realize its multi-beneficial potential for farmers (by premium prices), and consumers (by healthier and nutritious food). The importance of OA has been recognized by the most recent EU agro-environmental policies and green strategies, with an ambitious goal to have at least 25% of agroecosystems under organic management by 2030. Despite numerous financial supports and a multifold increase in OA land area, many member states are unlikely to achieve this goal, including Croatia, which currently has a share of only 8% (~109,000 ha) of lands in OA. Furthermore, converting conventional land to organic farming has not always led to an increase in value-added final OA products. EU policies related to OA have been focused on the area of land cultivated organically, rather than overall production performance, and financial subsidies have been essential to achieve this policy. Therefore, some of critical obstacles and challenges for OA under rising pressures due to global climate change, public health and geopolitical crises need to be managed by specifically designed policies and regulations, which would contribute to more sustainable OA, i.e., food safety and security.

An eco-friendly photo-responsive hyaluronic acid-based supramolecular polysaccharide hybrid hydrogels for plant growth regulation and heavy metal ions adsorption

Agrochemicals are widely used in agricultural production, but they may cause agrochemicals residues and environmental pollution. Polysaccharide-based materials have emerged as a promising biopolymer carrier for agrochemicals delivery. Herein, an eco-friendly, photo-responsive supramolecular polysaccharide hybrid hydrogels (HA-AAP-Guano-CD@LP) was constructed from arylazopyrazole-modified hyaluronic acid (HA-AAP), guanidinium functionalized β-cyclodextrin (Guano-CD), and laponite clay (LP) via synergistic host-guest and electrostatic interactions, which could realize the controlled release of plant growth regulators such as naphthalene acetic acid (NAA) and gibberellin (GA) and promote the growth of Chinese cabbage and alfalfa. More interestingly, after releasing the cargo, the hydrogels could be used to capture heavy metal ions via strong complexation between the ions and carboxyl groups. This polysaccharide-based supramolecular hybrid hydrogels may provide a new strategy to realize the precision agriculture by the controlled delivery of plant growth regulators and synergetic adsorption of pollutants.

Effect of plasma-activated water and buffer solution combined with ultrasound on fungicide degradation and quality of cherry tomato during storage

The purpose of this study was to examine plasma-activated buffer solution (PABS) and plasma-activated water (PAW) combined with ultrasonication (U) treatment on the reduction of chlorothalonil fungicide and the quality of tomato fruits during storage. To obtain PAW and PABS, an atmospheric air plasma jet was used to treat buffer solution and deionized water at different treatment times (5 and 10 min). For combined treatments, fruits were submerged in PAW and PABS, then sonicated for 15 min, and individual treatment without sonication. As per the results, the maximum chlorothalonil reduction of 89.29% was detected in PAW-U10, followed by 85.43% in PABS. At the end of the storage period, the maximum reduction of 97.25% was recorded in PAW-U10, followed by 93.14% in PABS-U10. PAW, PABS, and both combined with ultrasound did not significantly affect the overall tomato fruit quality in the storage period. Our results revealed that PAW combined with sonication had a significant impact on post-harvest agrochemical degradation and retention of tomato quality than PABS. Conclusively, the integrated hurdle technologies effectively reduce agrochemical residues, which helps to lower health hazards and foodborne illnesses.

An alternative approach to assess ecotoxicological effects of agrochemical combinations used in Brazilian aquaculture farms.

Agrochemicals used for treating and preventing aquaculture diseases are usually present in combination with other compounds, and the toxicity resulting from their chemical interactions presents an important reason to assess the ecotoxicity of compound mixtures in view to better understanding the joint action of chemicals and avoiding their environmental impacts. In this study, we evaluated the acute aquatic ecotoxicity of several compounds used in Brazilian fish farming (Oxytetracycline [OXT], Trichlorfon [TRC], and BioFish® [BIO]), both individually and in binary and ternary mixtures. Initial test concentrations were prepared according to the recommended concentrations for aquaculture application, and from these, a geometric dilution series was tested on two important fresh water quality indicator species, the microcrustacean Daphnia magna and the bacterium Aliivibrio fischeri. At the recommended pond application rate, TRC and BIO applied individually showed toxicity to the tested organisms in terms of the lowest-observed-effect concentration (LOEC), and D. magna was always more sensitive than A. fischeri. For the two test organisms, the results obtained with the binary mixtures showed that the TRC and BIO mixture was more toxic than TRC and OXT, which in turn was more toxic than OXT and BIO. The toxicity from all agrochemicals in the ternary mixture was more than that of the agrochemical combinations in the binary mixtures. Given the results presented in this study, it is evident that the mode of action and availability of the tested compounds undergo changes that increase toxicity when they are present in combination, and therefore, aquaculture wastewater treatment should be adopted to ensure decontamination of agrochemical residues.

Agrochemical Residues in Fish and Bivalves from Sepetiba Bay and Parnaiba River Delta, Brazil.

Accumulation of pesticides has a harmful impact on the environment and human health. The main goal of this work was to develop a method to determine and quantify the residues of thirteen pesticides in edible fish and bivalves such as parati (Mugil curema), seabass (Centropomus ssp.), mullet (Mugil brasiliensis), clams (Anomalocardia brasiliana) and mussel (Mytilus galloprovincialis) collected from Sepetiba Bay and Parnaiba River Delta (Brazil) between 2019 and 2020. Matrix solid-phase dispersion (MSPD) was used for extraction and quantification through gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). The method was validated (linearity, accuracy and precision) for fatty fish (Salmo salar), lean fish (Mugil curema) and bivalves (Mytilus edulis). The survey found linear correlation coefficients (r) equal to or greater than 0.9 for almost all analytes. The relative standard deviations (RSD) of five replicates were less than 20% for almost all analytes at different concentrations in lean fish, fatty fish and bivalves. Most analytes showed satisfactory accuracy. Alachlor herbicide was found in samples of seabass, mussels, clams and parati with levels ranging between 0.55 to 420.39 μg kg-1 dw. Ethion was found in parati (maximum 211.22 μg kg-1 dw), mussels (15.1 μg kg-1 dw) and clams (maximum 44.50 μg kg-1 dw). Alachlor was found in clams (maximum 93.1 μg kg-1 dw), and bifenthrin was found in parati (maximum 43.4 μg kg-1 dw) and clams (maximum 42.21 μg kg-1 dw). The validated method was satisfactory for the determination of eleven pesticides in the fatty fish matrix, and thirteen pesticides in the samples of lean fish and bivalves. The presence of alachlor, ethion and bifenthrin stands out.