Pesticide monitoring and ecotoxicological risk assessment in surface water bodies and sediments of a tropical agro-ecosystem

Pesticide pollution: toxicity, sources and advanced remediation approaches

The Food and Agricultural Organization of the United Nations (FAO) estimates that food production must rise by 70% to meet the demands of an additional 2.3 billion people by 2050. This forecast underscores the persistent reliance on pesticides, making it essential to assess their toxicity and develop effective remediation strategies. Given the widespread utilisation of pesticides, it requires an urgent need to evaluate their toxicity and explore feasible remediation approaches for their removal. Hence, this review provides an overview of the latest information on the presence, distribution, sources, fate, and trends of pesticides in global environmental matrices, emphasizing the ecological and health risks posed by pesticide pollution. Currently, the dominant remediation techniques encompass physical, chemical, and biological methods, yet studies focusing on advanced remediation techniques remain limited. This review critically evaluates both newer and traditional approaches to pesticide removal, offering a descriptive and analytical comparison of various methods. The selection of the appropriate treatment method depends largely on the nature of the pesticide and the effectiveness of the chosen technique. In many cases, technologies such as membrane bioreactors and the fenton process could be integrated with biological technologies to enhance performance and overcome limitations. The study concludes that a hybrid approach combining various remediation strategies offers the most effective and sustainable solution for pesticide removal. Finally, the review underscores the need for further scientific investigation into the most viable technologies while discussing the challenges and prospects of developing safe, reliable, cost-effective, and eco-friendly methods for removing pesticides from the environment.

Sampling strategy, quantification, characterization and hazard potential assessment of greywater from ships in the Baltic Sea

Ship-generated greywater contains a variety of pollutants which, through various pathways, usually are discharged into the sea. To understand the seasonal variation in greywater volumes, the contaminant concentrations in, and the potential hazard of, ship-generated greywater streams, a four-phase strategy for sampling, characterization and hazard assessment of greywater was developed and implemented. Eight greywater streams, sampled from five ships, were characterized for selected pollutants. The metals Zn, Cu, Mn and the metalloid, As, collectively contributed 98 % to the Hazard Index. Laundry greywater had the highest average concentration of phosphorus (42 mg/l) while galley greywater had the highest average concentration of nitrogen (30 mg/l). The geometric means of COD-Cr, BOD5, TSS and P exceeded the IMO resolution MEPC 227(64) guideline values for sewage effluent from Advanced Wastewater Treatment Plants. The results establish the basis for and contribute to discussions on, the optimization of ship-generated greywater management and the establishment of potential regulatory strategies in the Baltic Region.

Hexaflumuron insecticide exposure induces behavior alterations, hemato-biochemical disorders, antioxidant-immune dysfunction, and histopathological alterations in Nile tilapia (Oreochromis niloticus)

Hexaflumuron (HEX) insecticide is widely used in agriculture practices to fight crop insects. The toxicological effect of HEX on Nile tilapia (Oreochromis niloticus) was investigated in this study. Two hundred and forty fish (35.50 ± 1.45 g) were divided into six groups in four replicates (40 fish/group; 10 fish/replicate) and were exposed to six distinct HEX concentrations (0, 2, 4, 6, 8, and 10 mg L-1) for 96-h. The 96-h lethal concentration 50 (96-h LC50) of HEX was calculated to be 7.19 mg L-1. The fish exhibited reduced surface and middle swimming, aggressiveness, and tail-spreading behaviors with increasing bottom swimming and resting patterns after HEX exposure. HEX exposure resulted in body bleeding and fin rot. The erythrogram (red blood cell count, hemoglobin, and packed cell volume %) was significantly reduced with increased mean corpuscular volume by HEX exposure. HEX exposure decreased the white blood cells (WBCs) and differential WBC counts. Acute HEX exposure raised 8-hydroxy-2-deoxyguanosine level while lowering brain acetylcholine esterase activity. HEX exposure caused hepato-renal dysfunction and increased stress-related parameters (glucose and cortisol). Exposure to HEX reduced the immune responses (lysozyme, nitric oxide, immunoglobulin M, and complement 3). A substantial decrease in the antioxidant variables (reduced glutathione content and catalase) with increasing the malondialdehyde was noted by HEX exposure. Moreover, histopathological changes resulted from HEX exposure in the gills, liver, kidney, and spleen. These results indicate that HEX exposure induced behavioral changes, hepato-renal dysfunction, and immune-antioxidant disruption, indicating a possible physiological disruption in O. niloticus.

Temporal distribution and ecological risk assessment for pesticides in water from the north-central coastal zone of Sinaloa, Mexico

Water contamination with pesticides is one of the major pollution problems in northwestern Mexico, and this is due to the extensive use of pesticides in agriculture. In this research, water samples of ten sampling sites (fishing grounds, beaches, and both) were analyzed in the search for 28 pesticides (organochlorines, organophosphates, pyrethroids, carbamates, among other chemical classes), supplemented with a calculation of the resulting potential environmental risk. Pesticides were separated from the matrix by liquid-liquid extraction and quantified by gas chromatography coupled to electron micro-capture (organohalogenated) and pulsed flame photometric detectors (organophosphates). In addition, the ecotoxicological risk of pesticides in algae, invertebrates, and fish was assessed, based on seawater pesticide concentrations using the Risk Quotient (RQ) and Toxic Units (TU) approach. The results showed 18 pesticides identified in the analyzed samples, where cypermethrin and chlorpyrifos were identified with the maximum concentrations of 1.223 and 0.994 μg L-1, respectively. In addition, these two pesticides have been associated with acute toxic effects on algae, invertebrates, and fish. It is important to pay particular attention to the search for long-term alternatives to the use of chlorpyrifos and cypermethrin due to their high detection rates and the risks associated with their toxic properties. However, the adoption of alternative measures to synthetic pesticide control should be a priority, moving towards sustainable practices such as the use of biopesticides, crop rotation and polycultures.

Photocatalytic degradation of 2,4-dichlorophenoxyacetic acid by electrospun TiO2 nanofibres synthesised from two different titanium molecular precursors

The evaluation of the photocatalytic properties of electrospun TiO2 nanofibres (TiO2-NFs) synthesised in the same experimental conditions using two distinct precursors, tetraisopropyl orthotitanate (TTIP) and tetrabutyl orthotitanate (TNBT), with morphology and crystalline structure controlled by annealing at 460 °C for 3 h is presented. The presence of circular-shaped TiO2-NFs was corroborated by scanning electron microscopy (SEM). By using X-ray photoelectron spectroscopy (XPS), the chemical binding energies and their interactions of the TiO2 with the different incorporated impurities were determined; the most intense photoelectronic transitions of Ti 2p3/2 (458.39 eV), O 1 s (529.65 eV) and C 1 s (284.51 eV) were detected for TTIP and slightly blue-shifted for TNBT. By using energy-dispersive X-ray spectroscopy (EDS), the chemical element percentages in TiO2 were determined. Using X-ray diffraction, it was found that the annealed electrospun TiO2-NFs presented the anatase crystalline phase and confirmed by Raman scattering. Bandgap energies were determined by diffuse reflectance spectroscopy at room temperature. The photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide under exposure to ultraviolet light was studied using the TiO2-NFs obtained with the two molecular precursors. The results showed that the catalyst, prepared with the TTIP precursor, turned out to be the one that presented the highest photocatalytic activity with a half-life time (t1/2) of 28 min and a degradation percentage of 93%. The total organic carbon (TOC) in the solutions resulting from the 2,4-D degradation by the TiO2-NFs was measured, which showed a TOC removal of 50.67% for the TTIP sample and 36.14% for the TNBT sample. Finally, by using FTIR spectroscopy, the final chemical compounds of the degradation were identified as H2O and CO2.

Occurrence, removal and risk assessment of chemicals of emerging concern in selected rivers and wastewater treatment plants in western Kenya

Water resources play a crucial role in sustaining life on earth yet chemicals of emerging concern (CECs) arising from extensive human applications are an increasing threat towards their existence. In this study, we examined the occurrence, removal and potential risk of CECs found in rivers and wastewater treatment plants (WWTPs) in western Kenya. Samples were prepared by solid-phase extraction and analysed using high performance liquid chromatography-mass spectrometry with a target list of 785 compounds. Out of these, 333 and 352 (influent 322, effluent 265) compounds were quantified in rivers and wastewater respectively, with pharmaceuticals, industrial compounds, and pesticides being frequently detected in both rivers and WWTPs. Compounds with highest concentrations included saccharin (9.9 μg/L), metformin (7.5 μg/L), and oxypurinol (6.5 μg/L) in rivers whereas caffeine (280 μg/L), deoxycholic acid (179 μg/L), 2-oxindole (10.9 μg/L) and ibuprofen (8.1 μg/L) were found at high concentrations in WWTPs. Based on the types of crops grown, samples from maize growing regions recorded the highest number of pesticides (75) which coincided with the spraying season. The WWTP showed the capacity to eliminate some compounds although the removal efficiencies varied greatly with 204 compounds exhibiting an average removal efficiency exceeding 50 %. Based on the risk assessment, crustaceans had the highest potential risk for toxicity with toxic unit (TU) values up to 5.4 driven primarily by diazinon and dichlorvos followed by algae (TU up to 0.07) and fish (TU up to 0.01) in rivers. A similar trend was observed in WWTP with diazinon (TU up to 5.5), diuron (TU up to 0.07) and carbendazim (TU up to 0.006) driving the risk for crustaceans, algae and fish respectively. These findings highlight the significance of surface water and WWTPs as sources and sinks of CECs in the environment translating to potential risks on aquatic organisms and humans.

A review of smart electrochemical devices for pesticide detection in agricultural food and runoff contaminants

In the evolving field of food and agriculture, pesticide utilization is inevitable for food production and poses an increasing threat to the ecosystem and human health. This review systematically investigates and provides a comprehensive overview of recent developments in smart electrochemical devices for detecting pesticides in agricultural food and runoff contaminants. The focus encompasses recent progress in lab-scale and portable electrochemical sensors, highlighting their significance in agricultural pesticide monitoring. This review compares these sensors comprehensively and provides a scientific guide for future sensor development for infield agricultural pesticide monitoring and food safety. Smart devices address challenges related to power consumption, low cost, wearability, and portability, contributing to the advancement of agricultural sustainability. By elucidating the intricate details of these smart devices, this review offers a comprehensive discussion and roadmap for future research aimed at cost-effective, flexible, and smart handy devices, including novel electrocatalysts, to foster the development of next-generation agricultural sensor technology, opportunity and future direction for food security.

Occurrence of pharmaceuticals in Latin America: case study on hazard assessment and prioritization in Costa Rica

Pharmaceuticals are considered as contaminants of emerging concern, and their occurrence in diverse environmental matrices has been described during the last 25 years. Nonetheless, pharmaceutical occurrence has not been evenly described worldwide, and reports from some geographical areas such as most parts of Latin America are scarce. This work aims to address the situation of water pollution due to pharmaceuticals in Latin America by means of two main goals: i. First, reviewing the monitoring studies performed in Latin America on this topic (period 2009-2024), which were conducted in Brazil, Mexico, Colombia, Ecuador, Peru and Argentina, to highlight the most frequently detected compounds from each therapeutic group in the region. ii. Second, analyzing the case of Costa Rica through the hazard assessment and prioritization of pharmaceuticals based on the monitoring performed in this country (years 2011; 2018-2019). The monitoring in Costa Rica comprised a total of 163 sampling points: wastewater treatment plants (WWTPs) (14 urban WWTPs plus two landfill WWTPs; total samples n = 44 influents and n = 34 effluents), nine hospital effluents (n = 32), wastewater from livestock farms (six swine farms and seven dairy farms; n = 23 influents and n = 37 effluents), 64 continental surface water sampling points (n = 137), and 61 coastal seawater sampling points (n = 61). Risk assessment of detected concentrations by the hazard quotient (HQ) approach (period 2018-2019) revealed a total of 25 medium or high-hazard compounds (out of 37 detected compounds). The prioritization approach (which included the Frequency of Appearance (FoA), the Frequency of PNEC exceedance (FoE), and the Extent of predicted no-effect concentration (PNEC) exceedance (EoE)), showed a critical list of nine pharmaceuticals: caffeine, diphenhydramine, acetaminophen, lovastatin, gemfibrozil, ciprofloxacin, ibuprofen, doxycycline and norfloxacin. These compounds should be taken into account as a first concern during the implementation of environmental policies related to pharmaceutical products in the region.

Concentration-dependent effects of spinetoram on nontarget freshwater microalgae: A comparative study on Chlorella vulgaris and Microcystis aeruginosa

The rising global demand for agricultural products is leading to the widespread application of pesticides, such as spinetoram, resulting in environmental pollution and ecotoxicity to nontarget organisms in aquatic ecosystems. This research focused on assessing the toxicity of spinetoram at various concentrations (0, 0.01, 0.1, 0.5, 1.0, and 3.0 mg L-1) on two common freshwater microalgae, Chlorella vulgaris and Microcystis aeruginosa, to shed light on the ecotoxicological effects of insecticides. Our findings demonstrate that M. aeruginosa is more sensitive to spinetoram than is C. vulgaris, with a concentration-dependent reduction in the growth rate observed for M. aeruginosa, whereas only the highest concentration of spinetoram adversely affected C. vulgaris. At a concentration of 0.01 mg L-1, the growth rate of M. aeruginosa unexpectedly increased beginning on day 7, indicating a potential hormetic effect. Although initial exposure to spinetoram improved the photosynthetic efficiency of both microalgae strains at all concentrations, detrimental effects became apparent at higher concentrations and with prolonged exposure. The photosynthetic efficiency of C. vulgaris recovered, in contrast to that of M. aeruginosa, which exhibited limited recovery. Spinetoram more significantly inhibited the effective quantum yield of PSII (EQY) in M. aeruginosa than in C. vulgaris. Although spinetoram is not designed to target phytoplankton, its toxicity can disrupt primary productivity and modify phytoplankton-consumer interactions via bottom-up control mechanisms. This study enhances our understanding of spinetoram's ecotoxicity and potential effects on aquatic ecosystems.

Distribution and risk assessment of pesticide pollution in small streams adjoining paddy fields

The present investigation was planned to bridge the knowledge gap on spatiotemporal variations of pesticide pollution in small streams adjacent to paddy fields, and to visualize the associated risks in the aquatic ecosystems. We screened 106 pesticides using GCMSMS and LCMSMS from 10 small streams (n = 212, surface water samples) adjacent to paddy fields over seven months. Fifty-five pesticides were detected across different streams and months. The highest mean concentration was detected for fenobucarb (272 ng L-1), followed by thiamethoxam (199 ng L-1). The highest maximum concentration was detected for thiamethoxam ( 13,264 ng L-1), followed by triflumezopyrim ( 11,505 ng L-1). The highest detection frequency was recorded for fenobucarb (80.00%), followed by pretilachlor (79.00%). Out of the ten streams, Attabira stream had the highest mean number of pesticides detected in each sample. Maximum number of pesticides were detected in October followed by September. Pesticides namely, hexaconazole, pretilachlor, tricyclazole, fenobucarb and thiamethoxam were consistently detected across all streams. The risk assessment against the fishes, micro-invertebrates and algae were measured by risk quotient index (RQ). Twenty-five pesticides out of the detected pesticides (n = 55) had risk quotient values greater than 1. The highest RQmax values were observed in case of fenpropathrin followed by cyfluthrin-3. The highest RQmean value was observed in case of cyfluthrin, indicating its higher toxicity to fishes. The present study reveals that small streams are polluted with pesticides and there is a need to develop strategies and policy interventions in regularizing the pesticide uses for reducing the pesticide pollution in aquatic systems.

Combined toxic effects of polyethylene microplastics and lambda-cyhalothrin on gut of zebrafish (Danio rerio)

Microplastics (MPs), which are prevalent and increasingly accumulating in aquatic environments. Other pollutants coexist with MPs in the water, such as pesticides, and may be carried or transferred to aquatic organisms, posing unpredictable ecological risks. This study sought to assess the adsorption of lambda-cyhalothrin (LCT) by virgin and aged polyethylene MPs (VPE and APE, respectively), and to examine their influence on LCT's toxicity in zebrafish, specifically regarding acute toxicity, oxidative stress, gut microbiota and immunity. The adsorption results showed that VPE and APE could adsorb LCT, with adsorption capacities of 34.4 mg∙g-1 and 39.0 mg∙g-1, respectively. Compared with LCT exposure alone, VPE and APE increased the acute toxicity of LCT to zebrafish. Additionally, exposure to LCT and PE-MPs alone can induce oxidative stress in the zebrafish gut, while combined exposure can exacerbate the oxidative stress response and intensify intestinal lipid peroxidation. Moreover, exposure to LCT or PE-MPs alone promotes inflammation, and combined exposure leads to downregulation of the myd88-nf-κb related gene expression, thus impacting intestinal immunity. Furthermore, exposure to APE increased LCT toxicity to zebrafish more than VPE. Meanwhile, exposure to PE-MPs and LCT alone or in combination has the potential to affect gut microbiota function and alter the abundance and diversity of the zebrafish gut flora. Collectively, the presence of PE-MPs may affect the toxicity of pesticides in zebrafish. The findings emphasize the importance of studying the interaction between MPs and pesticides in the aquatic environment.

Assessing pesticide residues occurrence and risks in water systems: A Pan-European and Argentina perspective

Freshwater ecosystems face a particularly high risk of biodiversity loss compared to marine and terrestrial systems. The use of pesticides in agricultural fields is recognized as a relevant stressor for freshwater environments, exerting a negative impact worldwide on the overall status and health of the freshwater communities. In the present work, part of the Horizon 2020 funded SPRINT project, the occurrence of 193 pesticide residues was investigated in 64 small water bodies of distinct typology (creeks, streams, channels, ditches, rivers, lakes, ponds and reservoirs), located in regions with high agricultural activity in 10 European countries and in Argentina. Mixtures of pesticide residues were detected in all water bodies (20, median; 8-40 min-max). Total pesticide levels found ranged between 6.89 and 5860 ng/L, highlighting herbicides as the dominant type of pesticides. Glyphosate was the compound with the highest median concentration followed by 2,4-D and MCPA, and in a lower degree by dimethomorph, fluopicolide, prothioconazole and metolachlor(-S). Argentina was the site with the highest total pesticide concentration in water bodies followed by The Netherlands, Portugal and France. One or more pesticides exceeded the threshold values established in the European Water Framework Directive for surface water in 9 out of 11 case study sites (CSS), and the total pesticide concentration surpassed the reference value of 500 ng/L in 8 CSS. Although only 5 % (bifenthrin, dieldrin, fipronil sulfone, permethrin, and terbutryn) of the individual pesticides denoted high risk (RQ > 1), the ratios estimated for pesticide mixtures suggested potential environmental risk in the aquatic compartment studied.

Harnessing the potential of microalgae-based systems for mitigating pesticide pollution and its impact on their metabolism

Due to increased pesticide usage in agriculture, a significant concentration of pesticides is reported in the environment that can directly impact humans, aquatic flora, and fauna. Utilizing microalgae-based systems for pesticide removal is becoming more popular because of their environmentally friendly nature, ability to degrade pesticide molecules into simpler, nontoxic molecules, and cost-effectiveness of the technology. Thus, this review focused on the efficiency, mechanisms, and factors governing pesticide removal using microalgae-based systems and their effect on microalgal metabolism. A wide range of pesticides, like atrazine, cypermethrin, malathion, trichlorfon, thiacloprid, etc., can be effectively removed by different microalgal strains. Some species of Chlorella, Chlamydomonas, Scenedesmus, Nostoc, etc., are documented for >90% removal of different pesticides, mainly through the biodegradation mechanism. The antioxidant enzymes such as ascorbate peroxidase, superoxide dismutase, and catalase, as well as the complex structure of microalgae cell walls, are mainly involved in eliminating pesticides and are also crucial for the defense mechanism of microalgae against reactive oxygen species. However, higher pesticide concentrations may alter the biochemical composition and gene expression associated with microalgal growth and metabolism, which may vary depending on the type of strain, the pesticide type, and the concentration. The final section of this review discussed the challenges and prospects of how microalgae can become a successful tool to remediate pesticides.

Pesticide water variability and prioritization: The first steps towards improving water management strategies in irrigation hydro-agriculture areas

The presence of pesticides in aquatic ecosystems poses significant risks to non-target organisms, necessitating monitoring and environmental risk assessment. This study aimed to evaluate the dynamics and environmental risk of pesticides in a hydro-agricultural area with intensive agricultural practices, in the Mediterranean region (South of Portugal). Seasonality and location influenced pesticide numbers and concentrations, with the highest levels observed during the dry season. Triazines, phenylureas, and organophosphates were the predominant pesticide classes, with terbuthylazine, bentazone, terbutryn, diazinon, and metolachlor exhibiting the highest detection frequencies (68 % to 72 %). Notably, 44 % of the quantified pesticides are no longer authorized in Portugal, with 33 % posing a high environmental risk. Some insecticides, including imidacloprid, methiocarb, and malathion, were occasionally detected at concentrations that posed high risks to the aquatic ecosystem (RQ ≥ 1). Irgarol, an algicide used in irrigation canals, presented a high risk in 91 % of the analysed samples. The study's distribution profile of pesticides revealed a significant transportation of these compounds from reservoirs to irrigation hydrants, establishing them as a secondary source of crop and environmental contamination. Additionally, the assessment of spatial distribution and environmental risk allowed for the identification of specific pollutants in different locations, prioritizing them based on their ecotoxicological risk to aquatic ecosystems. These findings reinforce the importance of implementing management measures at the level of hydro-agricultural areas, helping to stop the cycle of pesticide contamination. Only this type of strategy will make it possible to protect water quality, biodiversity and the health of citizens, contributing to the European Union's objectives of improving the condition of freshwater bodies and promoting the sustainable use of pesticides.

Contaminants of emerging concern: Occurrence, analytical techniques, and removal with electrochemical advanced oxidation processes with special emphasis in Latin America

The occurrence of contaminants of emerging concern (CECs) in environmental systems is gradually more studied worldwide. However, in Latin America, the presence of contaminants of emerging concern, together with their environmental and toxicological impacts, has recently been gaining wide interest in the scientific community. This paper presents a critical review about the source, fate, and occurrence of distinct emerging contaminants reported during the last two decades in various countries of Latin America. In recent years, Brazil, Chile, and Colombia are the main countries that have conducted research on the presence of these pollutants in biological and aquatic compartments. Data gathered indicated that pharmaceuticals, pesticides, and personal care products are the most assessed CECs in Latin America, being the most common compounds the followings: atrazine, acenaphthene, caffeine, carbamazepine, ciprofloxacin, diclofenac, diuron, estrone, losartan, sulfamethoxazole, and trimethoprim. Most common analytical methodologies for identifying these compounds were HPLC and GC coupled with mass spectrometry with the potential to characterize and quantify complex substances in the environment at low concentrations. Most CECs' monitoring and detection were observed near to urban areas which confirm the out-of-date wastewater treatment plants and sanitization infrastructures limiting the removal of these pollutants. Therefore, the implementation of tertiary treatment should be required. In this tenor, this review also summarizes some studies of CECs removal using electrochemical advanced oxidation processes that showed satisfactory performance. Finally, challenges, recommendations, and future perspectives are discussed.

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

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

Combined effects of spinetoram and Microcystis aeruginosa on Daphnia pulex offspring: Maternal effects and multigenerational implications

The increasing occurrence of harmful algal blooms (HABs) in freshwater ecosystems detrimentally affect global water environments. Zooplankton's role in controlling HABs is hindered by contaminant exposure, necessitating research into combined stressors' ecological impacts. The response of Daphnia, a freshwater keystone species, to environmental stressors can be influenced by its maternal effects. Here, we investigated the combined effects of the world-widely used insecticide spinetoram and non-toxic HABs species Microcystis aeruginosa on the life-history traits of D. pulex offspring produced from different maternal food conditions. Four maternal groups were established, with each group receiving a specific blend of C. vulgaris (Ch) and M. aeruginosa (Ma) in varying proportions: A (100% Ch), B (90% Ch + 10% Ma), C (80% Ch + 20% Ma), and D (70% Ch + 30% Ma). The offspring from the third brood were gathered, and a 21-day experiment was carried out, involving various feeding groups (AA, AD, BA, BB, CA, CC, DA, and DD). Results demonstrated that grazing on M. aeruginosa by D. pulex induced maternal effects on their offspring, with the continuous exposure group showing an enhanced tolerance to M. aeruginosa. This study also unveiled that spinetoram could interfere with the molting of D. pulex, leading to developmental retardation. The Recovery Group exhibited an intriguing phenomenon: under the influence of both concentrations of the pesticide spinetoram (0.18, 0.35 μg L-1), D. pulex produced more offspring. This might be due to a combined strategy of allocating more energy towards reproduction in response to low-quality food and a potential hormetic effect from low concentrations of spinetoram. Assessing the interplay of combined stressors across multiple generations, encompassing harmful algal blooms (HABs) and environmental pollutants, is essential for predicting population responses to evolving environmental conditions. This understanding is vital for the protection and management of aquatic environments and ecosystems.

Progress in environmental monitoring and mitigation strategies for herbicides and insecticides: A comprehensive review

Herbicides and insecticides are pervasively applied in agricultural sector to increase the yield by controlling or eliminating bug vermin and weeds. Although, resistance development occurs, direct and indirect impact on human health and ecosystem is clearly visible. Normally, herbicides and pesticides are water soluble in nature; accordingly, it is hard to decrease their deadliness and to dis-appear them from the environment. They are profoundly specific, and considered as poisonous to various peoples in agricultural and industrial work places. In order to substantially reduce the harmful impacts, it is crucial to thoroughly examine the detection and mitigation measures for these compounds. The primary objective of this paper is to provide an overview of various herbicide and pesticide detection techniques and associated remedial techniques. A short summary on occurrence and harmful effects of herbicides/insecticides on ecosystem has been included to the study. The conventional and advanced, rapid techniques for the detection of insecticides and herbicides were described in detail. A detailed overview on several mitigation strategies including advanced oxidation, adsorption, electrochemical process, and bioremediation as well as the mechanism behind the strategic approaches to reduce the effects of growing pesticide pollution has been emphasized. Regardless of the detection techniques and mitigation strategies, the recent advances employed, obstacles, and perspectives have been discussed in detail.

Mechanistic insights into the effects of diuron exposure on Alexandrium pacificum

Diuron (N-(3,4-dichlorophenyl)-N,N‑dimethylurea, DCMU), a ureic herbicide, is extensively used in agriculture to boost crop productivity; however, its extensive application culminates in notable environmental pollution, especially in aquatic habitats. Therefore, the present study investigated the effect of diuron on the dinoflagellate Alexandrium pacificum, which is known to induce harmful algal blooms (HAB), and its potential to biodegrade DCMU. Following a four-day DCMU exposure, our results revealed that A. pacificum proficiently assimilated DCMU at concentrations of 0.05 mg/L and 0.1 mg/L in seawater, attaining a complete reduction (100 % efficiency) after 96 h for both concentrations. Moreover, evaluations of paralytic shellfish toxins content indicated that cells subjected to higher DCMU concentrations (0.1 mg/L) exhibited reductions of 73.4 %, 86.7 %, and 75 % in GTX1, GTX4, and NEO, respectively. Exposure to DCMU led to a notable decrease in A. pacificum's photosynthetic efficacy, accompanied by increased levels of reactive oxygen species (ROS) and suppressed cell growth, with a growth inhibition rate of 41.1 % at 72 h. Proteomic investigations pinpointed the diminished expression levels of specific proteins like SxtV and SxtW, linked to paralytic shellfish toxins (PSTs) synthesis, as well as key proteins associated with Photosystem II, namely PsbA, PsbD, PsbO, and PsbU. Conversely, proteins central to the cysteine biosynthesis pathways exhibited enhanced expression. In summary, our results preliminarily resolved the molecular mechanisms underlying the response of A. pacificum to DCMU and revealed that DCMU affected the synthesis of PSTs. Meanwhile, our data suggested that A. pacificum has great potential in scavenging DCMU.

Effect-based monitoring of two rivers under urban and agricultural influence reveals a range of biological activities in sediment and water extracts

Chemical contaminants, such as pesticides, pharmaceuticals and industrial compounds are ubiquitous in surface water and sediment in areas subject to human activity. While targeted chemical analysis is typically used for water and sediment quality monitoring, there is growing interest in applying effect-based methods with in vitro bioassays to capture the effects of all active contaminants in a sample. The current study evaluated the biological effects in surface water and sediment from two contrasting catchments in Aotearoa New Zealand, the highly urbanised Whau River catchment in Tāmaki Makaurau (Auckland) and the urban and mixed agricultural Koreti (New River) Estuary catchment. Two complementary passive sampling devices, Chemcatcher for polar chemicals and polyethylene (PED) for non-polar chemicals, were applied to capture a wide range of contaminants in water, while composite sediment samples were collected at each sampling site. Bioassays indicative of induction of xenobiotic metabolism, receptor-mediated effects, genotoxicity, cytotoxicity and apical effects were applied to the water and sediment extracts. Most sediment extracts induced moderate to strong estrogenic and aryl hydrocarbon (AhR) activity, along with moderate toxicity to bacteria. The water extracts showed similar patterns to the sediment extracts, but with lower activity. Generally, the polar Chemcatcher extracts showed greater estrogenic activity, photosynthesis inhibition and algal growth inhibition than the non-polar PED extracts, though the PED extracts showed greater AhR activity. The observed effects in the water extracts were compared to available ecological effect-based trigger values (EBT) to evaluate the potential risk. For the polar extracts, most sites in both catchments exceeded the EBT for estrogenicity, with many sites exceeding the EBTs for AhR activity and photosynthesis inhibition. Of the wide range of endpoints considered, estrogenic activity, AhR activity and herbicidal activity appear to be the primary risk drivers in both the Whau and Koreti Estuary catchments.

New findings on the occurrence, removal, and risk assessment of nonylphenol and octylphenol in industrial wastewater treatment plants in Korea

Nonylphenol (NP) and octylphenol (OP), extensively used in industries, can disrupt the human endocrine system and cause significant ecological toxicity. Therefore, in this study, we aimed to reveal the occurrence and removal characteristics of NP and OP in 30 industrial wastewater treatment plants (IWWTPs). Specifically, this study focused on 13 NP isomers that have not been previously reported. Additionally, the potential environmental risk of NP and OP discharged from IWWTPs was assessed using a minimum dilution factor (MDF), proposed for the first time in this study. We showed that the concentration and proportion of the isomer NP11 were higher than those of the other isomers in the IWWTP influents and effluents. We also identified an activated sludge-activated carbon adsorption process suitable for removing NP and OP. Finally, we proposed the MDF value of 11 for the potential environmental risk assessment of NP and OP, revealing that OP poses a higher risk than NP when discharged into surface water. These findings underscore the importance of focusing on the isomer NP11 and OP in IWWTPs.

Pharmaceuticals, hazard and ecotoxicity in surface and wastewater in a tropical dairy production area in Latin America

Pharmaceuticals comprise a complex group of emerging pollutants. Despite the significant number of pharmaceuticals used in veterinary medicine, the input of these compounds into the environment due to livestock activities has been scarcely described. This work assays for the first time in Central America the occurrence of pharmaceuticals in farm wastewater in an area devoted to dairy production, and in the surrounding surface waters. Among 69 monitored pharmaceuticals, a total of eight compounds were detected in wastewater samples collected from seven dairy farms after three sampling campaigns. Six pharmaceuticals were considered either of high (albendazole, lovastatin and caffeine) or intermediate estimated hazard (ciprofloxacin, acetaminophen and ketoprofen) based on the HQ approach, while 26% of the samples were considered of high estimated hazard according to the cumulative ∑HQ approach. Similarly, when ecotoxicological tests were applied, all the samples showed some level of toxicity towards Daphnia magna, and most samples towards Vibrio fischeri and Lactuca sativa. Fourteen pharmaceuticals were detected in surface water samples collected in the surroundings of the dairy production farms, including rural and urban areas. Seven out of these compounds showed high estimated risk (risperidone, diphenhydramine, trimethoprim, fluoxetine, ofloxacin, caffeine and ibuprofen), while three (gemfibrozil, ciprofloxacin and cephalexin) exhibited intermediate estimated risk. In a similar worrisome way, 27% of these samples were estimated to pose high environmental risk according to the pharmaceutical content. Despite being nontoxic for D. magna or V. fischeri, frequent inhibition (>20%) of GI in L. sativa was determined in 34% of surface water samples; such findings raise concern on the apparent inceptive environmental pollution and risk within the area. According to the pharmaceutical content patterns in both kinds of studied matrices, no clear evidence of significant contamination in surface water due to livestock activities could be retrieved, suggesting a main role of urban influence.

Occurrence, distribution, and risk assessment of pesticides in surface water and sediment in Jiangsu Province, China

The occurrence and distribution of 157 pesticides were investigated in surface water and sediment in Jiangsu Province, China. Gas chromatography-mass spectrometry was used to analyze and quantify these pesticides, and the risk quotient method was used to evaluate their respective environmental risk. The results showed that 91 pesticides were detected in surface water. The organophosphates (OPPs), fungicides, and amide herbicides were predominant. The total concentration in surface water ranged from 63.7 to 22,463 ng/L, 3.90 to 7262 ng/L, and ND to 34,120 ng/L, respectively. The mean concentration was 3479 ng/L, 1644 ng/L, and 1878 ng/L, respectively. The concentration range of detected pesticides in the Yangtze River Basin was generally lower than that in the Huai River Basin. In sediment samples, a total of 63 pesticides were detected. OPPs and amide herbicides were also ranked highest; the total concentration in sediment samples ranged from 2951 to 47,739 ng/g and 106 to 12,996 ng/g, respectively. And the mean concentrations was 6971 ng/g and 5130 ng/g, respectively. Suqian City had the highest concentration for OPPs and amide herbicides in the Huai River Basin, followed by Huai'an City, while Nanjing City and Yangzhou City ranked highest in the Yangtze River Basin. The spatial distribution of pesticides in Jiangsu Province indicated a concentration significantly higher in the western and northern regions than in the eastern and southern regions, and a concentration generally higher in lakes than in rivers. The risk assessment results showed that OPPs, fungicides, amide herbicides, organochlorines, and triazine herbicides in most surface water samples posed a high risk and had regional pollution characteristics. In sediment samples, organochlorines, carbamates, other herbicides, and other insecticides posed a high risk in northern Jiangsu Province, whereas OPPs, amide herbicides, and triazine herbicides posed high risks everywhere in Jiangsu Province.

Oxidative stress and mitochondrial damage in lambda-cyhalothrin toxicity: A comprehensive review of antioxidant mechanisms

Lambda-cyhalothrin, also known as cyhalothrin, is an efficient, broad-spectrum, quick-acting pyrethroid insecticide and acaricide and the most powerful pyrethroid insecticide in the world. However, there is increasing evidence that lambda-cyhalothrin is closely related to a variety of toxicity drawbacks (hepatotoxicity, nephrotoxicity, neurotoxicity and reproductive toxicity, among others) in non-target organisms, and oxidative stress seems to be the main mechanism of toxicity. This manuscript reviews the oxidative and mitochondrial damage induced by lambda-cyhalothrin and the signalling pathways involved in this process, indicating that oxidative stress occupies an important position in lambda-cyhalothrin toxicity. The mechanism of antioxidants to alleviate the toxicity of lambda-cyhalothrin is also discussed. In addition, the metabolites of lambda-cyhalothrin and the major metabolic enzymes involved in metabolic reactions are summarized. This review article reveals a key mechanism of lambda-cyhalothrin toxicity-oxidative damage and suggests that the use of antioxidants seems to be an effective method for preventing toxicity.

A combined approach for the estimation of groundwater leaching potential and environmental impacts of pesticides for agricultural lands

Pesticide pollution can degrade the quality of land, water, and air, and imposes risks on people, flora and fauna. Pesticides are frequently chosen based on their agricultural effectiveness and cost, rather than their potential environmental impacts. The aim of this study is to present a combined approach to estimate the leaching potential and environmental impacts of pesticides for agricultural lands. The pilot study area (PSA) is the agricultural plain of the Lower Aksu Stream Basin in Antalya - Turkey. The groundwater of the agricultural plain contributes to around half of the flow rate of the stream. The first phase of the combined approach involved pesticide monitoring to screen the target pesticides, the second phase involved evaluating the physicochemical properties of the target pesticides and estimating their leaching potential using several indices, and the third phase involved environmental impact analysis of the target pesticides using the Environmental Impact Quotient (EIQ) risk indicator. Additionally, Principal Component Analysis was conducted to examine the correlations between physicochemical parameters of pesticides and the leaching potential index results. By the application of the combined approach, 45 target pesticides were identified for the PSA and the indices were consistent to estimate similar leaching potentials for the same pesticides. Moreover, the computed EIQ-Field Use Rates provided valuable information to rank target pesticides according to their environmental impacts on consumer, farmworker and ecology. The applied methodology provided a practical approach to select pesticides with the least leaching potential and environmental impacts to protect water quality and ecosystem health.

Pesticide residues with hazard classifications relevant to non-target species including humans are omnipresent in the environment and farmer residences

Intensive and widespread use of pesticides raises serious environmental and human health concerns. The presence and levels of 209 pesticide residues (active substances and transformation products) in 625 environmental samples (201 soil, 193 crop, 20 outdoor air, 115 indoor dust, 58 surface water, and 38 sediment samples) have been studied. The samples were collected during the 2021 growing season, across 10 study sites, covering the main European crops, and conventional and organic farming systems. We profiled the pesticide residues found in the different matrices using existing hazard classifications towards non-target organisms and humans. Combining monitoring data and hazard information, we developed an indicator for the prioritization of pesticides, which can support policy decisions and sustainable pesticide use transitions. Eighty-six percent of the samples had at least one residue above the respective limit of detection. One hundred residues were found in soil, 112 in water, 99 in sediments, 78 in crops, 76 in outdoor air, and 197 in indoor dust. The number, levels, and profile of residues varied between farming systems. Our results show that non-approved compounds still represent a significant part of environmental cocktails and should be accounted for in monitoring programs and risk assessments. The hazard profiles analysis confirms the dominance of compounds of low-moderate hazard and underscores the high hazard of some approved compounds and recurring "no data available" situations. Overall, our results support the idea that risk should be assessed in a mixture context, taking environmentally relevant mixtures into consideration. We have uncovered uncertainties and data gaps that should be addressed, as well as the policy implications at the EU approval status level. Our newly introduced indicator can help identify research priority areas, and act as a reference for targeted scenarios set forth in the Farm to Fork pesticide reduction goals.

Occurrence and risk assessment of pharmaceuticals in hospital wastewater in Costa Rica

This work aims to determine the occurrence, hazard and prioritization of pharmaceuticals from hospital wastewater in Costa Rica through the monitoring of 70 compounds and assessing their environmental risk through a hazard quotient approach (HQ). Moreover, the quantification of selected antibiotic resistance genes (ARGs) was conducted for the first time in this matrix in this geographical location. Thirty-four pharmaceuticals were detected, being caffeine, 1,7-dimethylxanthine, acetaminophen, ibuprofen, naproxen, ciprofloxacin and ketoprofen the most frequent (>50% of the samples). Eighteen pharmaceuticals exhibited high hazard (HQ ≥ 1), while five more showed medium hazard (1 > HQ ≥ 0.1). Prioritization, which also included frequency parameters, revealed caffeine, lovastatin, diphenhydramine, acetaminophen, ibuprofen, ciprofloxacin, and sildenafil as the compounds of major concern. Similarly, cumulative hazard per sample (ΣHQ) estimated high hazard towards aquatic organisms in every sample. All selected ARGs, except mcr-1 (polymyxin resistance), were detected. Among genes conferring resistance to beta-lactams, blaCTX-M and blaKPC were the most abundant, related to resistance to cephalosporins and carbapenems. Ecotoxicological evaluation showed mostly low toxicity towards Daphnia magna and Vibrio fischeri, contrary to the marked effect observed towards Lactuca sativa. These findings provide relevant and novel information on the risk posed by hospital wastewater and their pharmaceutical content in the Latin American environmental context.

Water and sediment pesticide contamination on indigenous lands surrounded by oil palm plantations in the Brazilian Amazon

Large-scale oil palm cultivation with intensive pesticide use has been growing worldwide and reached the Brazilian Amazon. The rapid expansion of this crop over the last decade has reached vast areas, including the boundaries of different indigenous lands. This study aimed at assessing the occurrence of pesticide residues in surface and ground waters as well as drainage sediments in the Turé-Mariquita Indigenous Territory, in addition to other nearby indigenous villages in the northeastern state of Pará. Thirty-three (33) water samples were collected from streams, springs and from active and abandoned wells at 19 sampling points, as well as 16 sediment samples at 9 sampling sites both during dry and rainy seasons. In total, 49 environmental samples were taken during fieldworks and subsequently analyzed by means of liquid chromatography and mass-mass spectrometry. The analytical determination of pesticide residues showed the occurrence of three pesticides in the water both from streams and from wells, two of them knowingly used by the oil palm company: glyphosate-based herbicides (GBHs) and endosulfan insecticides. Although the highest glyphosate and endosulfan levels as well as the maximum concentration of glyphosate found in ground water are within the Brazilian environmental regulatory guidelines, all the values for human consumption found in the glyphosate-containing samples are well above the European Union regulatory standards. Our results draw the attention to the risks of biota contamination and human exposure to multiple-pesticide residues.

Neural System Impairment and Involved Microglia-Neuron Regulation of Broflanilide in Zebrafish Larvae

Broflanilide is widely used to control pests and has attracted attention due to its adverse effects on aquatic organisms. Our previous study showed that broflanilide has a negative impact on the central nervous system (CNS) at lethal dosages; however, its neural effects under practical situations and the underlying mechanisms remain unknown. To elucidate how broflanilide affects the CNS, we exposed zebrafish larvae to broflanilide at 16.9 and 88.0 μg/L (the environmentally relevant concentrations) for 120 h. Zebrafish locomotion was significantly disturbed at 88.0 μg/L, with a decreased moving distance and velocity accompanied by an inhibited neurotransmitter level. In vivo neuroimaging analysis indicated that the nerves of zebrafish larvae, including the axons, myelin sheaths, and neurons, were impaired. The number of neurons was significantly reduced after exposure, with an impaired morphological structure. These changes were accompanied by the abnormal transcription of genes involved in early CNS development. In addition, an increased total number of microglia and an elevated proportion of amoeboid microglia were observed after 88.0 μg/L broflanilide exposure, pointing out to an upstream role of microglia activation in mediating broflanilide neurotoxicity. Meanwhile, increased inflammatory cytokine levels and brain neutrophil numbers were observed, implicating significant inflammatory response and immune toxicity. Our findings indicate that broflanilide interferes with microglia-neuron regulation and induces neurodevelopmental disorders.

On-farm Occurrence of Pharmaceuticals and Their Environmental Hazard: Case Study of a Tropical Dairy farm

Animal husbandry wastewaters represent an important source of pharmaceuticals into the environment. This work aimed to evaluate the occurrence of pharmaceuticals and their hazard in wastewater from a model dairy farm from Costa Rica. Among the seven pharmaceuticals detected (acetaminophen, caffeine, carbamazepine, ibuprofen, ketoprofen, risperidone, sulfamethazine), caffeine, ibuprofen and acetaminophen showed the highest concentrations, while caffeine, carbamazepine and risperidone were the most frequently detected compounds. High (HQ ≥ 1) or medium (0.1 ≤ HQ < 1) hazard were estimated for three (caffeine, ibuprofen, risperidone) and two (acetaminophen, ketoprofen) pharmaceuticals, respectively; similarly, high overall hazard (∑HQ) and significant ecotoxicity were determined in samples from all sampling points. According to our results, the release of these aqueous matrices is a matter of environmental concern, as the treated wastewater is used for farm irrigation or directly released into nearby water streams. This work contributes to the knowledge on the scarcely described occurrence and risk of pharmaceuticals in Latin American regions.

Seasonal variation in pesticide residue occurrences in surface waters found in Narok and Bomet Counties, Kenya

Narok and Bomet are agricultural counties in Kenya which depend on flowing surface waters for farming activities. Agrochemicals have frequently been used to increase agricultural produce in this region. Occasionally, appropriate pesticide utilization measures are not followed. These surface waters are also consumed domestically by humans, livestock, and wild animals thus posing safety concerns to them. The current study sought to evaluate the levels and nature of pesticide residues found in surface waters in the dry and wet seasons of these counties. Eight water samples were collected in July (dry season) and October (wet season) at four different river sites in each of the two counties predetermined by the agricultural activity of its proximate environs. Pesticides extracted by solid phase extraction were analyzed by gas chromatography-mass spectrometry. At least 38 different pesticides were detected in the two counties with the highest concentration being recorded for chlorpyrifos and piperidine in Narok and Bomet counties, respectively. The pesticides chlorpyrifos, cypermethrin, cyfluthrin, and cyhalothrin were more prevalent in Narok County while triazine, semicarbazone, and epinephrine were more prevalent in Bomet County. There were significantly more pesticides detected during the wet season (P ≤ 0.05). Out of the nine prevalent pesticides detected, four of them posed serious ecotoxicology concerns with risk quotients above 1.0 (high risk); thus, there is a need for more government policy interventions in deterring farming near riparian lands and in training of famers regarding best practice for pesticide applications.

Pesticides in the hydrogeo-environment: a review of contaminant prevalence, source and mobilisation in India

Chemical pesticides in the hydrogeological system are a global concern as they pose a severe threat to humans and other organisms. In agriculture, around 4.12 million tonnes of pesticides were used globally in 2018, which is 50% more than in the 1990s. Various pesticides detected in the hydrogeological system of India since the 1990s have been documented and reviewed to understand the prevalence, source, history and degradation pathways. This review contributes to a better understanding of existing pesticide pollution and the state of hydrogeological resource deterioration. Small to excess levels of pesticide residues were detected in groundwater, surface water, soil, and sediments. Pesticides that were most commonly and predominantly found in the hydrogeological system were HCHs, DDTs, endosulfan, heptachlor, drins (aldrin, dieldrin, endrin), chlordane etc. β and γ-HCH isomers among HCHs, whereas p,p'-DDT and p,p'-DDE among the DDTs were detected most prevalently. In many regions, pesticide residue levels in water have exceeded the maximum residue limits of WHO and BIS, while those in soils and sediments have exceeded the threshold effect level and probable effect level. Higher pesticide residues were detected in the water resources of rural agricultural areas compared to peri-urban or urban areas. A positive correlation of pesticide residues between water resources and soil has been observed in some regions, suggesting a similar contamination source. Diagnostic ratios of pesticides reveal their source, history and degradation pathways. Diagnostic ratios observed in various studies conducted in India suggest historical as well as recent use of banned pesticides. Strengthening current policies and regulations, monitoring pesticide use, changes in pesticide application practices, awareness among farmers, and the use of prominent removal techniques are necessary to tackle pesticide contamination in India.

Acute mancozeb-fungicide exposure induces neuro-ethology disruption, health disorders, and immune-oxidative dysfunction in Nile tilapia (Oreochromis niloticus)

An acute exposure study of mancozeb (MAZ) fungicide was applied on Oreochromis niloticus for 96-h duration. Three hundred fish (20.50 ± 1.60 g) were assigned into six groups (50 fish/ group; 10 fish/replicate) and exposed to different six concentrations (0, 4, 8, 12, 16, and 20 mg L^-1) of MAZ for 96-h. The Probit analysis program was used to compute the 96-h lethal concentration 50 (96-h LC₅₀) of MAZ. During the exposure duration, the fish's behavior, clinical symptoms, and mortalities were recorded daily. After the exposure period was ended, the hematological, biochemical, immunological, and oxidant/antioxidant parameters were evaluated. The results of this study recorded the 96-h LC₅₀ of MAZ for O. niloticus to be 11.49 mg L^-1. Acute MAZ exposure badly affected the fish's behavior in the form of increased the breath gasping and swimming activity with aggressive mode. The exposed fish showed excessive body hemorrhages and fin rot. The survival rate of the exposed fish to MAZ was 100, 80, 66, 50, 38, and 30% in 0, 4, 8, 12, 16, and 20 mg L^-1 MAZ, respectively. The hematological indices (red blood cell count, hemoglobin, packed cell volume%, and white blood cell count) were significantly decreased by increasing the MAZ exposure concentration (8-20 mg L^-1). The acetylcholine esterase activity and immune indices (lysozyme, nitric oxide, immunoglobulin M, complement 3) were decreased by MAZ exposure (4-20 mg L^-1). Acute MAZ exposure induced hepato-renal dysfunction and elevated stress-related parameter (cortisol) by increasing the MAZ concentration. A significant reduction in the antioxidant parameters (total antioxidant activity, catalase, and superoxide dismutase) with increasing the lipid peroxidation marker (malondialdehyde) was noticed by acute MAZ exposure (4 -20 mg L^-1) in O. niloticus. Based on these outcomes, the MAZ exposure induced toxicity to the fish evident in changes in fish behavior, neurological activity, hepato-renal functioning, and immune-antioxidant responses which suggest physiological disruption.

The widespread presence of triazole fungicides in greenhouse soils in Shandong Province, China: A systematic study on human health and ecological risk assessments

Triazole fungicides (TFs) are extensively used on greenhouse vegetables and are ubiquitously detected in the environment. However, the human health and ecological risks associated with the presence of TFs in the soil are unclear. In this study, ten widely used TFs were measured in 283 soil samples from vegetable greenhouses across Shandong Province, China, and their potential human health and ecological risks were assessed. Among all soil samples, difenoconazole, myclobutanil, triadimenol, and tebuconazole were the top detected TFs, with detection rates of 85.2-100%; these TFs had higher residues, with average concentrations of 5.47-23.8 μg/kg. Although most of the detectable TFs were present in low amounts, 99.3% of the samples were contaminated with 2-10 TFs. Human health risk assessment based on hazard quotient (HQ) and hazard index (HI) values indicated that TFs posed negligible non-cancer risks for both adults and children (HQ range, 5.33 × 10-10 to 2.38 × 10-5; HI range, 1.95 × 10-9 to 3.05 × 10-5, <1). Ecological risk assessment based on the toxicity exposure ratio (TER) and risk quotient (RQ) values indicated that difenoconazole was a potential risk factor for soil organisms (TERmax = 1 for Eisenia foetida, <5; RQmean = 1.19 and RQmax = 9.04, >1). Moreover, 84 of the 283 sites showed a high risk (RQsite range, 1.09-9.08, >1), and difenoconazole was the primary contributor to the overall risk. Considering their ubiquity and potential hazards, TFs should be continuously assessed and prioritized for pesticide risk management.

Ecological risk assessment of pesticides on soil biota: An integrated field-modelling approach

Pesticide residues in soils can cause negative impacts on soil health as well as soil biota. However, research related to the toxicity and exposure risks of pesticides to soil biota are scarce, especially in the North China Plain (NCP) where pesticides are intensively applied. In this study, the occurrence and distribution of 15 commonly used pesticides in 41 fields in Quzhou county in the NCP were determined during the growing season in 2020. The ecological risks of pesticides to the soil biota, including earthworms, enchytraeids, springtails, mites and nitrogen mineralization microorganisms, were assessed using toxicity exposure ratios (TERs) and risk quotient (RQ) methods. Based on pesticide detection rates and RQs, pesticide hazards were ranked using the Hasse diagram. The results showed that pesticides were concentrated in the 0-2 cm soil depth. Chlorantraniliprole was the most frequently detected pesticide with a detection rate of 37%, while the highest concentration of 1.85 mg kg^-1 was found for carbendazim in apple orchards. Chlorpyrifos, carbendazim and imidacloprid posed a chronic exposure risk to E. fetida, F. candida and E. crypticus with the TERs exceeding the trigger value. Pesticide mixtures posed ecological risks to soil biota in 70% of the investigated sites. 47.5% of samples were ranked as high-risk, with the maximum RQ exceeding 490. According to the Hasse diagram, abamectin, tebuconazole, chlorantraniliprole and chlorpyrifos were ranked as the most hazardous pesticides for soil biota in the study region, indicating that alternative methods of pest management need to be considered. Therefore, practical risk mitigation solutions are recommended, in which the use of hazardous pesticides would be replaced with low-risk pesticides with similar functions from the Hasse diagram, or with biopesticides.

Flubendiamide induced genetic and cellular damages directly influence the life cycle of the oriental leaf worm, Spodoptera litura

Indiscriminate uses of insecticide greatly damage the environment as well as non-target organisms. Thus, multiple levels of bioassays can help better management of our environment. Flubendiamide is a phthalic acid diamide insecticide that ceases the function of insect muscle leading to paralysis and death. Here, we aimed to explore the effects of Flubendiamide on the life cycle of Spodoptera litura vis-a-vis the mode of action. Fourth instar larvae of the same age (120 ± 2 h) and size were fed with different concentrations (20-80 μg/mL) of Flubendiamide for 12-72 h. We performed a pharmacokinetics study, different biochemical assays, p450, Ecdysone receptor (EcR) and other genes expression analyses by Real-Time PCR and gross damages by Dye exclusion assay and histopathology. Our results demonstrate that the mean concentration of Flubendiamide after 48 h is 9.907 μg/mL and (i) altered the molting, metamorphosis, and reproduction at 80 μg/mL (24 h) (ii) increases all oxidative stress parameters (ROS/RNS, MDA, 8OHdG), decreases oxidative defense mechanisms (SOD, CAT, GST) at 80 μg/mL (48 h) and p450 in a time and concentration-dependent manner, (iii) activates CncC/Maf apoptotic pathways at 80 μg/mL concentration at 24 h while the expression declined from 48 h onwards, (iii) downregulates the EcR expression in a time and concentration-dependent manner, which might be responsible for disturbed molting, metamorphosis, and reproduction, and (iv) increase the expression of apoptotic genes (Caspase 1, -3, and - 5), in time and concentration-dependent manner causing gross morphological and histological damages. In conclusion, indiscriminate use of this insecticide can affect the ecosystem and have the capacity to cause multiple hazardous effects on experimental organisms. Thus, it warrants further investigations to improve and optimize the integrated pest management packages, including Flubendiamide for better management.

Transport model simulation prediction and environmental risk assessment of pyrethroid insecticides in urban artificial lakes caused by rainfall: A case study of Cloud Mountain Park in subhumid climate zone

Pyrethroid insecticides are among urban parks' most widely used and harmful insecticides. The advanced prediction method is the key to studying the pollution and diffusion risk of plant conservation insecticides in parks. A two-dimensional advection-dispersion model was established for the North Lake of Cloud Mountain Park in the subhumid area of Hebei Province. The temporal and spatial distribution of lambda-cyhalothrin pollution required by plant growth in artificial lakes under different rainfall intensities and the time of water renewal after rainfall was simulated and predicted. According to the model efficiency (E: 0.98), mean absolute error (MAE: 0.016-0.064 cm), and root mean square error (RMSE: 0.014-0.041 cm), the prediction results showed that the model fits well. The results showed that the concentration of lambda-cyhalothrin in the artificial lake was positively correlated with the increase in rainfall intensity. Under the three scenarios of moderate rain, heavy rain, and rainstorm, the variation of total pollutants into the lake over time conformed to the first-order dynamic equation (R²＞0.97), and the cumulative rates were 0.013 min^-1, 0.019 min^-1 and 0.022 min^-1, respectively. Under light rain, the accumulation rate of lambda-cyhalothrin showed a double-linear relationship, which was in accordance with the second-order kinetic equation (R²＞0.97). The rapid accumulation rate of early-stage rainfall was 0.0024 min^-1, and the slow accumulation rate of late-stage rainfall was 0.0019 min^-1. The human health risk assessment predicted by the simulation was lower than the hazard value (R_tgⁿ(a-1): 9.65 E^-11-1.12 E^-10 a-1). However, the potential risk value to aquatic species was higher (RQ: 0.33-23.05). In addition, the increase in rainfall intensity has no significant effect on the acceleration of water renewal time. The two-dimensional dispersion model of pollutants driven by water dynamics provided relevant examples for evaluating the impact of runoff on pesticide scour in parks and supplied scientific support for improving the management of artificial lakes in urban parks.

Multicompartmental monitoring of legacy and currently used pesticides in a subtropical lake used as a drinking water source (Laguna del Cisne, Uruguay)

A pilot annual monitoring survey (April 2018-March 2019) was conducted to investigate the presence of pesticides in superficial water and fish in Laguna del Cisne, one of the most critical drinking water sources in Uruguay. A total of 25 pesticide residues were detected in superficial water (89.3 % of the samples). Pesticide's temporal distribution was associated with crops and livestock practices, with higher occurrences in spring and summer than in autumn and winter. The most frequent compounds in superficial water were the insecticide chlorantraniliprole, and the herbicides glyphosate (including its metabolite AMPA) and metolachlor. The levels of Organochlorine pesticide, p,p'-DDT, was in some cases two order of magnitude above the international water quality guidelines for Ambient Water Criteria. In fishes, eight different pesticides were detected, at concentrations from 1000 to 453,000 ng·kg^-1. The most frequent pesticides found were propiconazole, chlorpyrifos, and p,p'-DDE. The widespread occurrence of pesticides in fish suggests potential exposure effects on fish populations and the aquatic ecosystem. The sampling approach of this work allowed monitoring the continuous concentrations of several pesticides in surface waters and fishes to establish the influence from past and current agriculture practices in Laguna del Cisne basin. For safety measures, continuous monitoring programs must be performed in this system to prevent toxicity impacts on aquatic organisms and human health.

Occurrence and environmental risk assessment of 22 pesticides in Brazilian freshwaters

Pesticide contamination in water resources is a global threat. Although usually found at low concentrations, pesticides raise considerable toxicological concerns, mainly when mixtures are considered. The occurrence of 22 pesticides (2,4 D, alachlor, aldicarb, aldrin, atrazine, carbendazim, carbofuran, chlordane, chlorpyrifos, DDT, diuron, glyphosate, lindane, mancozeb, methamidophos, metolachlor, molinate, profenofos, simazine, tebuconazole, terbufos, and trifluralin) was investigated, through consolidated database information, in surface freshwaters of Brazil. Moreover, scenarios of environmental risk assessment considering isolated compounds and mixtures were performed, as well as a meta-analytic approach for toxicity purposes. Pesticides in freshwater have been reported from 719 cities (12.9% of Brazilian cities), where 179 (3.2%) showed pesticide occurrence above the limit of detection or quantification. Considering cities with more than five quantified, 16 cities were prone to environmental risks considering individual risks. However, the number increased to 117 cities when the pesticide mixture was considered. The mixture risk was driven by atrazine, chlorpyrifos, and DDT. The national maximum acceptable concentrations (MAC) for nearly all pesticides are higher than the predicted no-effect concentration (PNEC) for the species evaluated, except aldrin. Our results show the need to consider mixtures in the environmental risk assessment to avoid underestimation and review MAC to protect aquatic ecosystems. The results presented here may guide the revision of the national environmental legislation to ensure the protection of Brazilian aquatic ecosystems.

Spatiotemporal distribution patterns and ecological risk of multi-pesticide residues in the surface water of a typical agriculture area in China

This study systematically investigated the occurrence, spatiotemporal distribution, and ecological risk of 106 pesticides in the surface water of the Jiaodong Peninsula in China. The results show that 52 pesticides, including 21 insecticides, 10 fungicides, and 21 herbicides, were detectable in the surface water. The concentrations of target pesticides in water samples ranged from 0.42 (tebuconazole in the wet season) to 645.31 ng/L (thiamethoxam in the normal season). The two most polluting and widespread pesticides were quintozene (maximum concentration of 481.46 ng/L and detection rate of 94 %) and atrazine (maximum concentration of 465.73 ng/L and detection rate of 100 %). The total pesticide concentrations in surface water in different seasons revealed the order of dry season > wet season > normal season. Based on aquatic pesticide concentrations, their frequency of occurrence, and effect concentrations, insecticides posed higher risks to aquatic organisms and human health than either fungicides or herbicides. Total pesticide concentrations were significantly positively correlated with suspended particulate matter, dissolved organic carbon, soil pH, normalized difference vegetation index, adjacent cropland area; and were negatively associated with adjacent grassland area. The cropland area largely influences pesticide distribution in the surface water of the Jiaodong Peninsula.

Ecotoxicity of pesticide formulations and their mixtures: the case of potato crops in Costa Rica

Despite their environmental implications, ecotoxicological information regarding pesticide mixtures is relatively scarce. This study aimed to determine the ecotoxicity of individual pesticide formulations and their mixtures (insecticides and fungicides), which are applied during the production cycle of potato, according to agricultural practices from a Latin American region in Costa Rica. Two benchmark organisms were employed: Daphnia magna and Lactuca sativa. First, the evaluation of individual formulations (chlorothalonil, propineb, deltamethrin+imidacloprid, ziram, thiocyclam and chlorpyrifos) revealed differences between available EC₅₀ for active ingredients (a.i.) and their respective formulations toward D. magna; on the contrary, no information could be retrieved from scientific literature for comparison in the case of L. sativa. In general, acute toxicity was higher toward D. magna than L. sativa. Moreover, interactions could not be determined on L. sativa, as the chlorothalonil formulation was not toxic at high levels and the concentration-response to propineb could not be fitted to obtain an IC₅₀ value. The commercial formulation composed of deltamethrin+imidacloprid followed the concentration addition model (when compared with parameters retrieved from individual a.i.) and the other three mixtures evaluated (I: chlorothalonil-propineb-deltamethrin+imidacloprid; II: chlorothalonil-propineb-ziram-thiocyclam; III: chlorothalonil-propineb-chlorpyrifos) produced an antagonistic effect on D. magna, thus suggesting less acute toxicity than their individual components. Subsequent chronic studies showed that one of the most toxic mixtures (II) negatively affected D. magna reproduction at sublethal concentrations indicating that this mixture poses a risk to this species if these pesticides co-exist in freshwater systems. These findings provide useful data to better estimate the impact of real agricultural practices related to the use of agrochemicals.

Monitoring and environmental risk assessment of agricultural fungicide and insecticides in water, sediment from Kumkale Plain, Çanakkale-Turkey

This study was conducted to assess pesticide residues in 34 water and sediment samples taken from Kumkale Plain of Çanakkale-Turkey. Residue analyses were performed with the use of Quick-Easy-Cheap-Efficient-Rugged-Safe (QuEChERS)-liquid chromatography/tandem mass spectrometry (LC-MS/MS) procedure. For method verification, blank sediment and water samples were spiked at two limits of quantification (LOQ) levels of the pesticides. Overall recovery was 81.66% for sediment and 91.50% for water samples. In sediment samples, chlorpyrifos-M had the highest concentration, pyridaben was encountered in the majority of the samples (15 samples) and the highest number of pesticides (35) was seen in sample no. s13. In water samples, methoxyfenozide had the greatest concentration, metalaxyl was encountered in the highest number of samples (three samples) and the highest number of pesticide (8) was seen in sample no.w13. Sample no. s13 and w13 were taken from around the fountain basin. Pyraclostrobin and chlorantraniliprole residues exceeded the national limits set for water. In terms of hazard quotient (HQ), pesticides in sediment and waters were found to be safe. Despite the safe nature of pesticide on samples, greater attention has been paid on toxicity of the residues. It was concluded that authorities should put strict regulations on agrochemicals to reduce health risks of these chemicals.

Distribution and risk assessment of pesticide residues in sediment samples from river Ganga, India

Indiscriminate use of pesticides leads to their entry in to the bottom sediments, where they are absorbed in the sediment's particle and thus, may become the consistent source of aquatic pollution. The present work was carried out to evaluate pesticide residues in the sediment samples and associated human health risk of commonly used pesticides along the basin of river Ganga. Total of 16 pesticides were analyzed along three stretches of river Ganga. The concentration of pesticides in the upper stretch ranged from ND to 0.103 μg/kg, in the middle stretch ND to 0.112 μg/kg, and in the lower stretch ND to 0.105 μg/kg. Strong positive correlation was found between total organic carbon and total pesticide residues in sediment samples. Carcinogenic and non-carcinogenic values were estimated below the threshold limit suggesting no associated risk. Risks associated with the inhalation route of exposure were found to be higher than the dermal and ingestion routes. Children were found at higher risk at each site from multiple routes of exposure than adult population groups. Toxic unit values were found to be below the threshold value suggesting no risk associated with exposure of pesticides from sediments. However, long term effects on ecological quality due to consistent pesticide exposure must not be ignored. Therefore, the present study focuses on concrete efforts like lowering the irrational used of pesticides, tapping of agricultural and domestic drains, advice to farmers for appropriate use of pesticide doses, to reduce the threat of pesticide pollution in the river system and possible human health risk.

Ecological risk assessment of pesticides in sediments of Pampean streams, Argentina

After their application in agricultural areas, pesticides are dispersed throughout the environment, causing contamination problems. In Argentina, the main promoter of transgenic biotechnology in the region, the total consumption of agrochemicals has increased significantly in recent years. Most chemicals dumped near surface waters eventually end up in bottom sediments and can be toxic to the organisms that live there. However, published data on the mixing of pesticides in this compartment is still scarce. The objective of this work was to detect and quantify pesticide residues in the sediment of rural streams in the Pampas region and to carry out acute and chronic risk assessment in these aquatic ecosystems. The study area comprises the mountainous system of Tandilia, located in one of the most productive agricultural areas in the country. The concentration of atrazine, acetochlor, chlorpyrifos, cypermethrin, and 2,4-D in the sediment of four rural streams was determined in three different seasons, and the toxic units (TU) and the risk ratios (RQ) were calculated. All the compounds analyzed were detected in most of the sampling seasons and study sites, at concentrations higher than those established in the national and international quality guidelines for the protection of aquatic biota in surface waters and for human consumption. Chlorpyrifos, cypermethrin, and acetochlor were the main pesticides contributing to the TU and RQ values, representing a medium or high ecological risk in most of the sites. Therefore, the evaluation of these pesticides in the bottom sediments could be a decisive factor in assessing the risk to the aquatic environment.

Occurrence, sources, and spatial variation of POPs in a mountainous tropical drinking water supply basin by passive sampling

Persistent organic pollutants (POPs) are widely distributed along the world and their levels in surface waters may pose a risk to human health due to consumption of contaminated water or fish long-term exposure to contaminated water. The occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Piedras river (Colombia) is a problem of serious concern since freshwater is conducted to a drinking water supply system that provides more than 3 million users. In this research, we deployed silicone rubber membranes as passive samplers in two sampling campaigns at seven sampling stations selected along the river, to assess sources and spatial variation of POPs. The measurements confirmed freely dissolved concentration of the EPA prioritized PAHs (excluding naphthalene), PCBs, heptachlor isomers, dieldrin, endosulfan isomers, among other POPs at trace levels in the water source. The Risk Quotient (RQ) method was applied to prioritize POPs with the highest potential toxicity over aquatic ecosystems. The OCP Heptachlor overcome RQ, while Dieldrin and Endosulfan, and some PAHs congeners such as Perylene, Pyrene, Benzo[a]pyrene, and Fluoranthene displayed medium-risk RQ. Significant differences between sampling stations assessed by One-way ANOVA suggested that the main PAHs and PCBs sources to the river were the punctual discharge from the WWTP and a leachate discharge form a landfill located in the study area. Additionally, nonpoint sources of OCPs were identified. Our results showed that the origin of PAHs and PCBs are associated with urban activities, while the contribution of OCPs is related to the presence of legacy pesticides from past usage in agricultural activities in the basin.

Health Risk Assessment of Pesticide Residues in Drinking Water of Upper Jhelum Region in Kashmir Valley-India by GC-MS/MS

Globally growing demand for agricultural and farm foods has more or less become dependent on chemical pesticides to maintain the supply chain, which undoubtedly boosts agricultural production. However, pesticides not only impact the target pests but cause hazard to human health. Pesticides are ubiquitous and can be found in almost every component of the environment. They can therefore impair human and biota health when present over the threshold level. The present study assessed the concentration of commonly used pesticides for agricultural purposes but get mixed in different sources of water, as such fifteen sampling sites along the upper Jhelum basin of Kashmir valley were chosen. For the analysis, 60 water samples were obtained from different water sources. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to determine pesticide residues in water samples. Pesticide residues from 10 of the 26 commonly used pesticides were detected in water samples. Difenoconazole had the highest concentration among the pesticides detected, with a mean concentration of 0.412 ± 0.424 μg/L ranging from 0.0 μg/L to 0.8196 μg/L. The target hazards quotient (THQ) was used to quantify the possible noncarcinogenic health risks associated with drinking pesticide-contaminated water. Only chlorpyrifos and quinalphos were detected >1 in RWS3 (1.6571), RWS4 (1.0285), RWS14 (1.2571), and RWS15 (1.2000) sample sites, implying that the drinking water poses a health risk to humans. Hence, pesticide hazards should be mitigated and rigorous monitoring is needed to reduce pesticide residues in drinking water.

Pesticides monitoring in surface water of a subsistence agricultural catchment in Uganda using passive samplers

Pesticides are intensely used in the agricultural sector worldwide including smallholder farming. Poor pesticide use practices in this agronomic setting are well documented and may impair the quality of water resources. However, empirical data on pesticide occurrence in water bodies of tropical smallholder agriculture is scarce. Many available data are focusing on apolar organochlorine compounds which are globally banned. We address this gap by studying the occurrence of a broad range of more modern pesticides in an agricultural watershed in Uganda. During 2.5 months of the rainy season in 2017, three passive sampler systems were deployed at five locations in River Mayanja to collect 14 days of composite samples. Grab samples were taken from drinking water resources. In these samples, 27 compounds out of 265 organic pesticides including 60 transformation products were detected. In the drinking water resources, we detected eight pesticides and two insecticide transformation products in low concentrations between 1 and 50 ng/L. Also, in the small streams and open fetch ponds, detected concentrations were generally low with a few exceptions for the herbicide 2,4-D and the fungicide carbendazim exceeding 1 ug/L. The widespread occurrence of chlorpyrifos posed the largest risk for macroinvertebrates. The extensive detection of this compound and its transformation product 3,4,5-trichloro-2-pyridinol was unexpected and called for a better understanding of the use and fate of this pesticide.

Occurrence, distribution, and driving factors of current-use pesticides in commonly cultivated crops and their potential risks to non-target organisms: A case study in Hainan, China

Multiple pesticides are heavily applied in crops grown in China's tropics due to the prevalence of diseases and pests, thus posing potential risks to nontarget organisms (e.g., honeybees, lacewings, ladybugs, and humans). However, there is little information on this topic. This study is the first assessment of the occurrence, driving factors, and ecological/human health risks of 32 current-use pesticides (CUPs) in 10 frequently-planted crops collected from practicing rice-vegetable rotation systems in Hainan, China. Of the 132 whole crop samples, 44 (33.3 %) residues from ≥8 pesticides were detected in 9.09 % of crop samples with concentrations ≥0.5 mg kg-1. Six pesticide residues, namely carbendazim, pyraclostrobin, acetamiprid, thiophanate methyl, phoxim, and imidacloprid, were detected in 72.7 % of samples, with concentrations ranging from 0.0021 to 13.5 (median = 0.032) mg kg-1. Among them, carbendazim, pyraclostrobin, and acetamiprid were the most common, contributions from 10.2 to 25.5 % and a detection frequency ranging from 25.6 to 56.1 %. The order of total concentration of 32 CUPs (∑32 CUP) concentrations during the year was January > May > November > August and vegetables > rice, being highly related with pesticides usage pattern, crop type, plant accumulation/dissipation and plant lipid contents. The ecological risk quotients (RQs) to four beneficial terrestrial organisms showed that 9.6-39.1 % of samples posed a potential medium or high ecological risk, with 13.6-65.9 % of samples at ∑RQ > 1 being highly affected by the residues of neonicotinoids and emamectin benzoate. Emamectin benzoate (8.9 %) and acetamiprid (5.6 %) exceeded the individual Maximum Residue Levels based on Chinese legislation (GB2763-2021). Moreover, cumulative dietary exposure presented a higher risk to humans in 11.0 and 22.0 % of the cases for acute and chronic, mainly originating from the higher concentration contributors of systemic pesticides in edible crops. Therefore, the regulation and monitoring of CUP residues is imperative for rice-vegetable rotation systems in tropical China to avoid negative effects on nontarget organisms.

Occurrence, spatiotemporal dynamics, and ecological risk of fungicides in a reservoir-regulated basin

As an indispensable type of pesticide, fungicides have been somewhat neglected compared to insecticides and herbicides. Heavy fungicide application in agricultural regions may generate downstream ecological concerns via in-stream transport, and the reservoir complicates the process. Monitoring fungicide exposure and exploring reservoir effect on fungicide transport is the key to develop the downstream strategies of agricultural diffusion pollution control. Here, we investigated the exposure, spatiotemporal dynamics, and ecological risk of fungicides in a reservoir-regulated agricultural basin, located in the middle of the Yangtze River Basin, China. Seven fungicides were preliminarily identified and exhibited high detection frequencies (>85 %) in subsequent quantification of water samples from three sampling activities. The total concentration of fungicides ranged from 2.47 to 560.29 ng/L, 28.35 to 274.69 ng/L, and 13.61 to 146.968 ng/L in April, September, and November, respectively. Overall, the contamination levels of fungicides were in the ascending order of April < November < September. The spatial distribution of fungicides was closely associated with the dense of cultivated land, supporting its agricultural source. Furthermore, the reservoir plays a retention role in fungicides, alleviating ecological pressure downstream during the water storage period. Yet, due to the alternation of "source" and "sink" function of the reservoir, the contribution of Zijiang River to the fungicide load in the Yangtze River Basin still needs further attention. Although there is no acute risk posed by fungicides, even in the high-exposure scenario, the chronic ecological risk could not be ignored. Agricultural intensive regions, coupled with the reservoir, provide rather substantial chronic ecological concerns. Carbendazim has been designated as a priority pollutant that contributes significantly to cumulative chronic risk. Thus, we emphasize strengthening the supervision of fungicides in surface water and rationally restricting the use of carbendazim in agricultural operations.

Fish biomarker responses reflect landscape anthropic disturbance in savanna streams

Disturbance in the landscape surrounding streams can interfere with water quality and cause harm to aquatic organisms. In this study, we evaluate the influence of land use on the genetic and biochemical biomarkers of fish in streams of Brazilian savanna (Cerrado). We also evaluated whether biomarker responses are seasonally consistent. For this purpose, individuals of the Neotropical tetra fish Astyanax lacustris were exposed in cages for 96 h, in 13 streams draining agroecosystems with different degrees of disturbance during the dry and wet seasons. After exposure, blood, liver, and gills were collected for multibiomarker analyses (micronuclei, erythrocytic nuclear abnormalities, lipid peroxidation, antioxidant enzymes, and biotransformation enzyme). The results showed that the gradient of anthropic disturbance was positively associated with genotoxic damage (erythrocytic nuclear abnormalities) and negatively associated with antioxidant and biotransformation enzymes of the liver in both seasons. No association of the gradient of anthropic disturbance with the frequency of micronuclei and for most gill enzymes was found for both seasons. Landscape disturbance was also negatively associated with water quality in the wet season. These results indicate that changes in land use interfere with the genetic and biochemical processes of organisms. Thus, the multibiomarker approach may represent an effective strategy for assessing and monitoring terrestrial landscape disturbance.