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.

Effects of Multiple Environmental Stressors on Zoobenthos Communities in Shallow Lakes: Evidence from a Mesocosm Experiment.

Multiple stressors, including climate change, eutrophication, and pesticide contamination, are significant drivers of the decline in lake zoobenthos. Zoobenthos play a crucial role in aquatic ecosystems, impacting energy dynamics, nutrient cycling, and sediment degradation. However, these stressors have led to a decrease in the abundance and diversity of zoobenthos, resulting in notable changes in species composition and structure. Eutrophication typically increases zoobenthos abundance while reducing taxonomic diversity. Climate change, such as warming and heatwaves, also affects the zoobenthos community structure, with different species exhibiting varying levels of adaptability to temperature changes. Additionally, pesticides like imidacloprid have negative effects on the survival and growth of zoobenthos. However, the interactions between imidacloprid and other stressors remain understudied. Here, we used 48 mesocosms (2500 L) to simulate shallow lakes. We combined nutrient loading, sustained warming, and the imidacloprid pesticide to test how these stressors interactively influence the survival and community of zoobenthos. The experimental results demonstrate that elevated temperatures have a significant impact on aquatic benthic organisms under different treatment conditions. The increase in temperature led to a notable rise in species richness and α-diversity, primarily attributed to the stimulation of metabolic activities in zoobenthos, promoting their growth and reproduction. This finding underscores the potential influence of climate change on aquatic benthic ecosystems, particularly in terms of its promoting effect on α-diversity. However, it is essential to note that elevated temperatures also reduced ß-diversity among different sites, implying a potential trend toward homogenization in zoobenthos communities under warmer conditions. Moreover, this study revealed the interactive effects of multiple stressors on the diversity of aquatic benthic communities. Specifically, the pesticide imidacloprid's impact on zoobenthos is not isolated but demonstrates complex effects within various treatment interactions. In the presence of both temperature elevation and the addition of imidacloprid, the presence of imidacloprid appears to counteract the adverse effects of temperature elevation, resulting in increased species diversity. However, when imidacloprid coincides with nutrient input, it significantly affects α-diversity negatively. These findings highlight the complexity of zoobenthos responses to multiple stressors and how these factors influence both α-diversity and ß-diversity. They provide valuable insights for further research on the conservation and management of ecosystems.

Biodegradation of carbofuran by Pseudomonas aeruginosa S07: biosurfactant production, plant growth promotion, and metal tolerance.

Pesticides are an indispensable part of modern farming as it aids in controlling pests and hence increase crop yield. But, unmanaged use of pesticides is a growing concern for safety and conservation of the environment. In the present study, a novel biosurfactant-producing bacterium, Pseudomonas aeruginosa S07, was utilized to degrade carbofuran pesticide, and it was obtained at 150 mg/L concentration; 89.2% degradation was achieved on the 5th day of incubation in in vitro culture condition. GC-MS (gas chromatography and mass spectrometry) and LC-MS (liquid chromatography and mass spectrometry) analyses revealed the presence of several degradation intermediates such as hydroxycarbofurnan, ketocarbofuran, and hydroxybenzofuran, in the degradation process. The bacterium was found to exhibit tolerance towards several heavy metals: Cu, Co, Zn, Ni, and Cd, where maximum and least tolerance were obtained against Co and Ni, respectively. Additionally, the bacterium also possesses plant growth-promoting activity showing positive results in nitrogen fixation, phosphate solubilising, ammonia production, and potassium solubilizing assays. Thus, from the study, it can be assumed that the bacterium can be useful in the production of bioformulation for remediation and rejuvenation of pesticide-contaminated sites in the coming days.

Low-dose chemical stimulation and pest resistance threaten global crop production.

Pesticide resistance increases and threatens crop production sustainability. Chemical contamination contributes to the development of pest resistance to pesticides, in part by causing stimulatory effects on pests at low sub-toxic doses and facilitating the spread of resistance genes. This article discusses hormesis and low-dose biological stimulation and their relevance to crop pest resistance. It highlights that a holistic approach is needed to tackle pest resistance to pesticides and reduce imbalance in accessing food and improving food security in accordance with the UN's Sustainable Development Goals. Among others, the effects of sub-toxic doses of pesticides should be considered when assessing the impact of synthetic and natural pesticides, while the promotion of alternative agronomical practices is needed to decrease the use of agrochemicals. Potential alternative solutions include camo-cropping, exogenous application of phytochemicals that are pest-suppressing or -repelling and/or attractive to carnivorous arthropods and other pest natural enemies, and nano-technological innovations. Moreover, to facilitate tackling of pesticide resistance in poorer countries, less technology-demanding and low-cost practices are needed. These include mixed cropping systems, diversification of cultures, use of 'push-pull cropping', incorporation of flower strips into cultivations, modification of microenvironment, and application of beneficial microorganisms and insects. However, there are still numerous open questions, and more research is needed to address the ecological and environmental effects of many of these potential solutions, with special reference to trophic webs.

Pesticide residues in nectar and pollen of melon crops: Risk to pollinators and effects of a specific pesticide mixture on Bombus terrestris (Hymenoptera: Apidae) micro-colonies.

Residues detected in pollen collected by honey bees are often used to estimate pesticide exposure in ecotoxicological studies. However, for a more accurate assessment of pesticides effect on foraging pollinators, residues found directly on flowers are a more realistic exposure approximation. We conducted a multi-residue analysis of pesticides on pollen and nectar of melon flowers collected from five fields. The cumulative chronic oral exposure Risk Index (RI) was calculated for Apis mellifera, Bombus terrestris and Osmia bicornis to multiple pesticides. However, this index could underestimate the risk since sublethal or synergistic effects are not considered. Therefore, a mixture containing three of the most frequently detected pesticides in our study was tested for synergistic impact on B. terrestris micro-colonies through a chronic oral toxicity test. According to the result, pollen and nectar samples contained numerous pesticide residues, including nine insecticides, nine fungicides, and one herbicide. Eleven of those were not applied by farmers during the crop season, revealing that melon agroecosystems may be pesticide contaminated environments. The primary contributor to the chronic RI was imidacloprid and O. bircornis is at greatest risk for lethality resulting from chronic oral exposure at these sites. In the bumblebee micro-colony bioassay, dietary exposure to acetamiprid, chlorpyrifos and oxamyl at residue level concentration, showed no effects on worker mortality, drone production or drone size and no synergies were detected when pesticide mixtures were evaluated. In conclusion, our findings have significant implications for improving pesticide risk assessment schemes to guarantee pollinator conservation. In particular, bee pesticide risk assessment should not be limited to acute exposure effects to isolated active ingredients in honey bees. Instead, risk assessments should consider the long-term pesticide exposure effects in both pollen and nectar on a range of bees that reflect the diversity of natural ecosystems and the synergistic potential among pesticide formulations.

Triazoles and Strobilurin Mixture Affects Soil Microbial Community and Incidences of Wheat Diseases.

Pesticides are widely used in agriculture as a pest control strategy. Despite the benefits of pesticides on crop yields, the persistence of chemical residues in soil has an unintended impact on non-targeted microorganisms. In the present study, we evaluated the potential adverse effects of a mixture of fungicides (difenoconazole, epoxiconazole, and kresoxim-methyl) on soil fungal and bacterial communities, as well as the manifestation of wheat diseases. In the fungicide-treated soil, the Shannon indices of both fungal and bacterial communities decreased, whereas the Chao1 indices did not differ compared to the control soil. Among bacterial taxa, the relative abundances of Arthrobacter and Sphingomonas increased in fungicide-treated soil due to their ability to utilize fungicides and other toxic compounds. Rhizopus and plant-beneficial Chaetomium were the dominant fungal genera, with their prevalence increasing by 2-4 times in the fungicide-treated soil. The genus Fusarium, which includes phytopathogenic species, which are notably responsible for root rot, was the most abundant taxon in each of the two conditions but its relative abundance was two times lower in fungicide-treated soils, consistent with a lower level of disease incidence in plants. The prediction of metabolic pathways revealed that the soil bacterial community had a high potential for degrading various pollutants, and the soil fungal community was in a state of recovery after the application of quinone outside inhibitor (QoI) fungicides. Fungicide-treated soil was characterized by an increase in soil microbial carbon, compared with the control soil. Collectively, the obtained results suggest that the application of difenoconazole, epoxiconazole, and kresoxim-methyl is an effective approach for pest control that does not pose a hazard for the soil ecosystem in the short term. However, it is necessary to carry out additional sampling to take into account the spatio-temporal impact of this fungicide mixture on the functional properties of the soil.

Remediation of Water Using a Nanofabricated Cellulose Membrane Embedded with Silver Nanoparticles.

The removal of pesticide pollution is imperative, because of their high environmental load and persistence, and their potential for bioaccumulation in, and toxicity to the environment. Most pesticides are found to be toxic even at trace levels. AgNPs can be effectively used for the adsorption of pesticides, and the incorporation of the AgNPs onto a support polymeric membrane enhances their effectiveness and reduces the potential unwanted consequences of intentionally adding free nanoparticles to the environment. Here, silver nanoparticles (AgNPs) were synthesized using a reliable, eco-friendly, and one-step "green" method, by reacting Mentha Piperita (mint) extract with AgNO3 aqueous solution at 60 °C in a microwave. The resulting high surface area nanoparticles are both economic and effective environmental remediation agents, playing a promising role in the elimination of aquatic pesticide pollution. Embedding the nanoparticles into a cellulose membrane at a low concentration (0.1 g) of AgNPs was shown to result in effectively adsorption of representative pesticides (Cypermethrin, Paraquat, and Cartap) within 60 min, while increasing the concentration of nanoparticles incorporated into the membrane further enhanced the removal of the exemplar pesticides from water. The high adsorption capacity makes the cellulose-AgNPs membrane an excellent substrate for the remediation of pesticide-polluted water.

Recent Advances in Nanomaterial-Based Biosensors for Pesticide Detection in Foods.

Biosensors are a simple, low-cost, and reliable way to detect pesticides in food matrices to ensure consumer food safety. This systematic review lists which nanomaterials, biorecognition materials, transduction methods, pesticides, and foods have recently been studied with biosensors associated with analytical performance. A systematic search was performed in the Scopus (n = 388), Web of Science (n = 790), and Science Direct (n = 181) databases over the period 2016-2021. After checking the eligibility criteria, 57 articles were considered in this study. The most common use of nanomaterials (NMs) in these selected studies is noble metals in isolation, such as gold and silver, with 8.47% and 6.68%, respectively, followed by carbon-based NMs, with 20.34%, and nanohybrids, with 47.45%, which combine two or more NMs, uniting unique properties of each material involved, especially the noble metals. Regarding the types of transducers, the most used were electrochemical, fluorescent, and colorimetric, representing 71.18%, 13.55%, and 8.47%, respectively. The sensitivity of the biosensor is directly connected to the choice of NM and transducer. All biosensors developed in the selected investigations had a limit of detection (LODs) lower than the Codex Alimentarius maximum residue limit and were efficient in detecting pesticides in food. The pesticides malathion, chlorpyrifos, and paraoxon have received the greatest attention for their effects on various food matrices, primarily fruits, vegetables, and their derivatives. Finally, we discuss studies that used biosensor detection systems devices and those that could detect multi-residues in the field as a low-cost and rapid technique, particularly in areas with limited resources.

Pesticides in surface freshwater: a critical review.

The objective of this study was to critically review studies published up to November 2021 that investigated the presence of pesticides in surface freshwater to answer three questions: (1) in which countries were the studies conducted? (2) which pesticides are most evaluated and detected? and (3) which pesticides have the highest concentrations? Using the Prisma protocol, 146 articles published from 1976 to November 2021 were included in this analysis: 127 studies used grab sampling, 10 used passive sampling, and 9 used both sampling techniques. In the 45-year historical series, the USA, China, and Spain were the countries that conducted the highest number of studies. Atrazine was the most evaluated pesticide (56% of the studies), detected in 43% of the studies using grab sampling, and the most detected in passive sampling studies (68%). The compounds with the highest maximum and mean concentrations in the grab sampling were molinate (211.38 µg/L) and bentazone (53 µg/L), respectively, and in passive sampling, they were oxyfluorfen (16.8 µg/L) and atrazine (4.8 µg/L), respectively. The levels found for atrazine, p,p'-DDD, and heptachlor in Brazil were higher than the regulatory levels for superficial water in the country. The concentrations exceeded the toxicological endpoint for at least 11 pesticides, including atrazine (Daphnia LC50 and fish NOAEC), cypermethrin (algae EC50, Daphnia and fish LC50; fish NOAEC), and chlorpyrifos (Daphnia and fish LC50; fish NOAEC). These results can be used for planning pesticide monitoring programs in surface freshwater, at regional and global levels, and for establishing or updating water quality regulations.

Detecting the combined toxicity of 18 binary and 24 ternary pesticide combinations to carboxylesterase based on fluorescence probe technology.

A rapid test method for the determination of pesticide toxicity was established by using carboxylesterase (CES) and fluorescence probe ACE-NH based on the principle of enzyme inhibition, and this method was applied to detect the combined toxicity of 18 binary and 24 ternary pesticide combinations commonly used for fruits and vegetables to CES. The results show that chlorpyrifos + carbendazim, carbofuran + carbendazim, imidacloprid + carbendazim, imidacloprid + dimethomorph, dimethoate + dimethomorph, prochloraz + carbendazim and imidacloprid + acetamiprid + carbendazim had synergistic effects under three concentration gradients, it indicated that most binary combinations containing carbendazim or imidacloprid had synergistic effects. Based on structure-activity relationship between pesticides and CES, pesticides with phosphate ester bonds had great toxicity to CES, or though they have no toxicity to CES alone, they showed a strong synergistic effect when mixed with other pesticides. Pesticides with amide or ester bond had medium toxicity and little synergistic effect. Pesticides with urea, carbamate or nitrite nitrogen group had little or no toxicity, while there was a strong synergistic effect after mixing with other pesticides. The test method and results in this study can provide scientific basis for risk assessment of cumulative exposure to mixed pesticide residues.

Minimized Atrazine Risks to Crop Security and Its Residue in the Environment by a Rice Methyltransferase as a Regulation Factor.

Atrazine (ATZ) is an agricultural pesticide for controlling field weeds. ATZ accumulates in many crops, posing high risks to crop production and food safety. Characterizing one of the novel rice MT genes named Oryza sativa atrazine-responsive methyltransferase (OsARM) showed that the expression of OsARM was associated with DNA demethylation (hypomethylation) in its promoter region. The enhancement of OsARM expression was manifested by the attenuated symptoms of ATZ toxicity including better growth and lower ATZ accumulation in plants. The promoted capacity of detoxification was confirmed by transgenic rice overexpression OsARM lines and also functionally proved by CRISPR-Cas9 knockout mutants. The transgenic lines accumulate more ATZ metabolites in rice and lower concentrations in the growth environment, pointing out that ATZ metabolism or degradation can be intensified. The ATZ-induced DNA demethylation is an important hallmark representing the epigenetic mechanism, which is required for the extra OsARM expression to facilitate ATZ disappearance in rice and the environment.

Residues of neonicotinoids in soil, water and people's hair: A case study from three agricultural regions of the Philippines.

Synthetic pesticides such as neonicotinoids are commonly used to treat crops in tropical regions, where data on environmental and human contamination are patchy and make it difficult to assess to what extent pesticides may harm human health, especially in less developed countries. To assess the degree of environmental and human contamination with neonicotinoids we collected soil, water and people's hair in three agricultural regions of the Philippines and analysed them by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS-MS). Five neonicotinoids, namely acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam were targeted. Residues of neonicotinoids were found in 78% of 67 soil samples from the three provinces. Total neonicotinoid loads ranged on average between 0.017 and 0.89 µg/kg in soils of rice, banana and vegetable crops, and were 130 times higher (113.5 µg/kg) in soils of a citrus grove. Imidacloprid was the most prevalent compound at an average of 0.56 µg/kg in soil while thiacloprid was below the limit of detection. Half of the eight water samples from a rice field and nearby creek contained residues of imidacloprid (mean 1.29 ng/L) and one contained thiamethoxam (0.15 ng/L). Residues of neonicotinoids were found in 81% of 99 samples of people's hair from the surveyed regions (average total concentrations 0.14 to 1.18 ng/g, maximum 350 ng/g). Hair residue levels correlated well with the concentrations of thiamethoxam and total residues in soils from the same locality (r = 0.98). The presence of thiacloprid in 15% of the hair samples but not in soil samples suggests an additional route of exposure among people, which is most likely to be through ingestion of agricultural food and drinks available in the market.

A spatial model of honey bee colony collapse due to pesticide contamination of foraging bees.

We develop a model of honey bee colony collapse based on contamination of forager bees in pesticide contaminated spatial environments. The model consists of differential and difference equations for the spatial distributions of the uncontaminated and contaminated forager bees. A key feature of the model is incorporation of the return to the hive each day of forager bees. The model quantifies colony collapse in terms of two significant properties of honey bee colonies: (1) the fraction of contaminated forager bees that fail to return home due to pesticide contamination, and (2) the fraction of forager bees in the total forager bee population that return to the sites visited on the previous day. If the fraction of contaminated foragers failing to return home is high, then the total population falls below a critical threshold and colony collapse ensues. If the fraction of all foragers that return to previous foraging sites is high, then foragers who visit contaminated sites multiple times have a higher probability of becoming contaminated, and colony collapse ensues. This quantification of colony collapse provides guidance for implementing measures for its avoidance.

Pesticide residues in agricultural topsoil from the Hainan tropical riverside basin: Determination, distribution, and relationships with planting patterns and surface water.

Pesticide residues were assessed in rice-vegetable rotation topsoil from tropical riverside basin. The 256 tropical topsoil samples from the Nandu River Basin (NRB) and Wanquan River Basin (WRB) in Hainan (China) were taken from 2018 to 2019. A total of 32 current-use pesticides (CUPs) and nine legacy pesticides (LPs) were detected using a method based on a QuEChERS technique. The highest residues were from the fungicide carbendazim (257.2 µg/kg) and the insecticide imidacloprid (139.4 µg/kg). The nine LPs (8 organochlorine pesticides and chlorpyrifos) were detected in 84.4% of the samples with mean concentrations ranging from 0.02 to 675.4 µg/kg. The two most commonly detected pesticides were imidacloprid and emamectin benzoate with detection rates of 96.8% and 91.8%, respectively. The highest total concentration of pesticides from the NRB and WRB was detected in July. The highest average number of multi-residues (16) was recorded in January, compared to 14 and 12 in July and November, respectively. There was a significant correlation between the multiple pesticide residues in soil and vegetable planting types (p < 0.01). There was a significant positive correlation between the pesticide number in topsoil and the pesticide number in water (p < 0.01). The multiple pesticide residues found in surface water were consistent with those in topsoil, suggesting a potential risk of water contamination in the rice-vegetable rotation.

Pesticide contamination drives adaptive genetic variation in the endemic mayfly Andesiops torrens within a semi-arid agricultural watershed of Chile.

Agrichemical contamination can provoke evolutionary responses in freshwater populations. It is a particularly relevant issue in semi-arid regions due to the sensitivity of endemic species to pollutants and to interactions with temperature stress. This paper investigates the presence of pesticides in rivers within a semi-arid agricultural watershed of Chile, testing for their effects on population genetic characteristics of the endemic mayfly Andesiops torrens (Insecta, Ephemeroptera). Pesticides were detected in sediment samples in ten out of the 30 sites analyzed throughout the upper part of the Limarí watershed. To study the evolutionary impact of such contamination on A. torrens, we used a genome-wide approach and analyzed 2056 single nucleotide polymorphisms (SNPs) loci in 551 individuals from all sites. Genetic differentiation was weak between populations, suggesting high gene flow across the study area. While we did not find evidence of pesticide effects on genetic diversity nor on population differentiation, the allele frequency of three outlier SNP loci correlated significantly with pesticide occurrence. Interrogation of genomic resources indicates that two of these SNPs are located within functional genes that encode for the low-density lipoprotein receptor-related protein 2 and Dumpy, both potentially involved in insect cuticle resistance processes. Such genomic signatures of local adaptation are indicative of past adverse effects of pesticide exposure on the locally adapted populations. Our results reveal that A. torrens is sensitive to pesticide exposure, but that a high gene flow may confer resilience to contamination. This research supports the contention that A. torrens is an ideal model organism to study evolutionary responses induced by pesticides on non-target, endemic species.

An Environmental Model of Honey Bee Colony Collapse Due to Pesticide Contamination.

We develop a model of honey bee colony collapse based on the contamination of forager bees in environmental regions contaminated with pesticides. An important feature of the model is the daily homing capacity each day of foragers bees. The model consists of difference equations describing the daily homing of uncontaminated and contaminated forager bees, with an increased homing failure of contaminated bees. The model quantifies colony collapse in terms of the fraction of contaminated bees subject to this increased homing failure. If the fraction is sufficiently high, then the hive falls below a viability threshold population size that leads to rapid disintegration. If the fraction is sufficiently low, then the hive can rise above the viability threshold and attain a stable population level.

Adsorption performance and mechanism of magnetic reduced graphene oxide in glyphosate contaminated water.

In this study, the magnetic reduced graphene oxide (RGO/Fe3O4), with easy separation and high adsorption performance, was prepared and used to treat glyphosate (GLY) contaminated water. GLY adsorption performance of RGO/Fe3O4 was investigated, and influences of pH, adsorption time, temperature, contaminant concentration, and competing anions were analyzed. Moreover, the adsorption mechanism was discussed in the light of several characterization methods, including scanning electron microscopy (SEM), energy dispersive spectrum (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the RGO/Fe3O4 presented a significant GLY adsorption capacity and acid condition was beneficial for this adsorption. The pseudo-second-order kinetic model and the Langmuir model correlated satisfactorily to the experimental data, indicating that this process was controlled by chemical adsorption and monolayer adsorption. Thermodynamic studies revealed that the adsorption of glyphosate onto RGO/Fe3O4 was spontaneous, endothermic, and feasible process. High temperatures were beneficial to GLY adsorption. The GLY adsorption mechanism of RGO/Fe3O4 was mainly attributed to hydrogen-bond interaction, electrostatic interaction, and coordination. Therefore, the RGO/Fe3O4 investigated in this research may offer an attractive adsorbent candidate for treatment of glyphosate contaminated water and warrant further study as a mechanism for glyphosate efficient removal.

Groundwater contamination with 2,6-dichlorobenzamide (BAM) and perspectives for its microbial removal.

The pesticide metabolite 2,6-dichlorobenzamide (BAM) is very persistent in both soil and groundwater and has become one of the most frequently detected groundwater micropollutants. BAM is not removed by the physico-chemical treatment techniques currently used in drinking water treatment plants (DWTP); therefore, if concentrations exceed the legal threshold limit, it represents a sizeable problem for the stability and quality of drinking water production, especially in places that depend on groundwater for drinking water. Bioremediation is suggested as a valuable strategy for removing BAM from groundwater by deploying dedicated BAM-degrading bacteria in DWTP sand filters. Only a few bacterial strains with the capability to degrade BAM have been isolated, and of these, only three isolates belonging to the Aminobacter genus are able to mineralise BAM. Considerable effort has been made to elucidate degradation pathways, kinetics and degrader genes, and research has recently been presented on the application of strain Aminobacter sp. MSH1 for the purification of BAM-contaminated water. The aim of the present review was to provide insight into the issue of BAM contamination and to report on the current status and knowledge with regard to the application of microorganisms for purification of BAM-contaminated water resources. This paper discusses the prospects and challenges for bioaugmentation of DWTP sand filters with specific BAM-degrading bacteria and identifies relevant perspectives for future research.

Pesticide survey in water and suspended solids from the Uruguay River Basin, Argentina.

The Uruguay River is receptor of pollutants, such as pesticides, from agriculture activities along its course. The present study reports concentration levels of organochlorinate, organophosphorus, and other pesticides in water and suspended solids in nine sampling sites of the Uruguay River. Data analyses included principal component analysis (PCA) to assess differences between sampling sites contamination. Most of the tested pesticides were ubiquitous due to the widely use in the chemical control of pests implemented in the region. Detected concentrations of aldrin, chlordane, dieldrin, endrin, heptachlor epoxide, lindane, 4,4'-DDT, endosulfan, chlorpyrifos, diazinon, methyl-parathion, and malathion were found to be over regional and international concentration level guidelines, according to the European Union, the US Environmental Protection Agency, or the Argentinean Secretariat of Environment and Sustainable Development. For this reason, future studies in Uruguay River Basin are needed.

Earthworm tolerance to residual agricultural pesticide contamination: field and experimental assessment of detoxification capabilities.

This study investigates if acclimatization to residual pesticide contamination in agricultural soils is reflected in detoxification, antioxidant enzyme activities and energy budget of earthworms. Five fields within a joint agricultural area exhibited different chemical and farming histories from conventional cultivation to organic pasture. Soil multiresidual pesticide analysis revealed up to 9 molecules including atrazine up to 2.4 ng g(-1) dry soil. Exposure history of endogeic Aporrectodea caliginosa and Allolobophora chlorotica modified their responses to pesticides. In the field, activities of soluble glutathione-S-transferases (sGST) and catalase increased with soil pesticide contamination in A. caliginosa. Pesticide stress was reflected in depletion of energy reserves in A. chlorotica. Acute exposure of pre-adapted and naïve A. caliginosa to pesticides (fungicide Opus(®), 0.1 µg active ingredient epoxiconazole g(-1) dry soil, RoundUp Flash(®), 2.5 µg active ingredient glyphosate g(-1) dry soil, and their mixture), revealed that environmental pre-exposure accelerated activation of the detoxification enzyme sGST towards epoxiconazole.