Spatial and Depth Profiling of Agricultural Formulations in Leaf Tissue Using LAESI Mass Spectrometry.

Formulating agrochemical products involves combining several chemical components, including the active ingredient(s), to obtain a final product with desirable efficacy. A formulated product incorporates additional components to modulate properties that enhance the efficacy of the active(s) by modifying physical properties such as viscosity, hydrophobicity, miscibility, and others. In plants, understanding the formulation's ability to spread on tissues and penetrate through the outer layer is critical in evaluating the efficacy of the final product. We have previously demonstrated the use of mass spectrometry imaging to determine spreadability. In this study, we show that laser ablation electrospray mass spectrometry (LAESI-MS) can be a valuable tool to assess the penetrability of formulations into the leaf tissues by selectively sampling various layers of leaf tissue by manipulating the laser intensity and analyzing the ablated material using a mass spectrometer. Using this technique, we were able to identify a formulation composition that can improve the penetration and uptake of active ingredients.

Fragmentation characteristics-based nontargeted screening method of exogenous chemical residues in animal-derived foods using reversed-phase and hydrophilic interaction liquid chromatography-high-resolution mass spectrometry.

Fragmentation characteristics are crucial for nontargeted screening to discover and identify unknown exogenous chemical residues in animal-derived foods. In this study, first, fragmentation characteristics of 51 classes of exogenous chemical residues were summarized based on experimental mass spectra of standards in reversed-phase and hydrophilic interaction liquid chromatography-high-resolution mass spectrometry (MS) and mass spectra from the MassBank of North America (MoNA) library. According to the proportion of fragmentation characteristics to the total number of chemical residues in each class, four screening levels were defined to classify 51 classes of chemical residues. Then, a nontargeted screening method was developed based on the fragmentation characteristics. The evaluation results of 82 standards indicated that more than 90 % of the chemical residues with MS/MS spectra can be identified at concentrations of 100 and 500 µg/kg, and about 80 % can be identified at 10 µg/kg. Finally, the nontargeted screening method was applied to 16 meat samples and 21 egg samples as examples. As a result, eight chemical residues and transformation products (TPs) of 5 classes in the exemplary samples were found and identified, in which 3 TPs of azithromycin were identified by fragmentation characteristics-assisted structure interpretation. The results demonstrated the practicability of the nontargeted screening method for routine risk screening of food safety.

A liquid chromatography-mass spectrometry method for the enantioselective multiresidue determination of nine chiral agrochemicals in urine using an enrichment procedure based on graphitized carbon black.

Many agrochemicals are chiral molecules, and most of them are marketed as racemates or diastereomeric mixtures. Stereoisomers that are not the active enantiomer have little or no pesticidal activity and can exert serious toxic effects towards non-target organisms. Thus, investigating the possible exposure to different isomers of chiral pesticides is an urgent need. The present work was aimed at developing a new enantioselective high-performance liquid chromatography-mass spectrometry method for the simultaneous determination of nine chiral pesticides in urine. Two solid-phase extraction (SPE) procedures, based on different carbon-based sorbents (graphitized carbon black (GCB) and buckypaper (BP)), were developed and compared. By using GCB, all analytes were recovered with yields ranging from 60 to 97%, while BP allowed recoveries greater than 54% for all pesticides except those with acid characteristics. Baseline separation was achieved for the enantiomers of all target agrochemicals on a Lux Cellulose-2 column within 24 min under reversed-phase mode. The developed method was then validated according to the FDA guidelines for bioanalytical methods. Besides recovery, the other evaluated parameters were precision (7-15%), limits of detection (0.26-2.21 µg/L), lower limits of quantitation (0.43-3.68 µg/L), linear dynamic range, and sensitivity. Finally, the validated method was applied to verify the occurrence of the pesticide enantiomers in urine samples from occupationally exposed workers.

Assessment of intensive periurban agriculture soil quality applying biomarkers in earthworms.

Periurban agriculture in Argentina is carried out by farmers without adequate control. The indiscriminate agrochemical application for productivity improvement negatively impacts the environment. The objective of this work was to test the quality of periurban agricultural soils by performing bioassays with Eisenia andrei as an indicator. Soils belonging to two orchards with intensive production (S: strawberry/broccoli crop plot and G: tomato/pepper crop greenhouse - Moreno District, Buenos Aires, Argentina) were sampled during 2015 and 2016. As subcellular biomarkers, cholinesterases (ChE), carboxylesterases (CaE), and glutathione-S-transferases (GST) activities were analysed in E. andrei (7-day exposure). While no effect on ChE activities was observed, CaE activities were significantly reduced 18% (S-2016 soil). GST activities were increased 35% and 30% by S-2016 and G-2016, respectively. CaE decrease together with GST increase could be indicative of a negative disturbance. Concerning whole organism biomarkers, reproduction (56-day exposure), avoidance (3-day exposure), and feeding activity (bait-lamina test, 3-day exposure) were analysed. A reduced cocoons' viability (50%), hatchability (55%), accompanied by a low number of juveniles (50%) were observed in all cases. Additionally, the earthworms exhibited significant avoidance responses to S-2015, S-2016 and G-2016 whereas G-2015 soil induced migration. No significant effect on the feeding activity was registered in any case. Most of the E. andrei biomarkers tested could constitute an early warning of harmful effects produced by polluted periurban soils, even if the agrochemical treatment applied remains unknown. The results reveal the need to develop an action plan to avoid further deterioration of the productive soil.

Variability in the levels of fungicide residues in final beer as they are influenced by various sequences of agrochemicals used for treatment on hops.

The fate of during brewing of pesticides (organic compounds and copper) from hops was determined to reveal linkages between various pesticide sequences applied in hop yards and the level of pesticides in beer. For this purpose, laboratory-scale brewing trials were carried out with conventional hops from four localities in which pest control spray programs varied. Pesticide residue analysis in samples of hopped wort, young beer, and beer was carried out by liquid chromatography in tandem with mass spectrometry (LC-MS/MS). Cu concentrations were determined using inductively coupled plasma mass spectrometry (ICP-MS). The transfer rates (%) of individual pesticides were calculated to demonstrate their ability to be transferred from hops to the brewed solutions. The pesticides exhibited different transfer rates correlating well with their log p values; however, the obtained transfer data were not related to their concentration in hops. The average transfer rates calculated for ametoctradin (15% ± 5%), mandipropamid (38% ± 4%), boscalid (48% ± 5%), and azoxystrobin (47% ± 2%) increased in good correlation with their descending log P values. On the contrary, the transfer rates of copper residues were related to residual concentrations of copper in hops and exhibited logarithmic dependency. The carryover of the sum of all pesticides in the four samples ranged from 36% to 49%, averaging 42% ± 6%. The data showed no substantial influence of various pesticide spray sequences on the percentages of overall pesticide residues carried over into beer.

Target and non-target analysis of organochlorine pesticides and their transformation products in an agrochemical-contaminated area.

Organochlorine pesticides show biological toxicity and their degradation typically takes many years. Previous studies of agrochemical-contaminated areas have mainly focused on limited target compounds, and emerging pollutants in soil have been overlooked. In this study, we collected soil samples from an abandoned agrochemical-contaminated area. Target analysis and non-target suspect screening by gas chromatography coupled with time-of-flight mass spectrometry were combined for qualitative and quantitative analysis of organochlorine pollutants. Target analysis showed that dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) were the main pollutants. With concentrations between 3.96 × 106 and 1.38 × 107 ng/g, these compounds posed significant health risks at the contaminated site. Non-target suspect screening identified 126 organochlorine compounds, most of which were chlorinated hydrocarbons and 90% of the compounds contained a benzene ring structure. The possible transformation pathways of DDT were inferred from proven pathways and the compounds identified by non-target suspect screening that had similar structures to DDT. This study will be useful for studies of the degradation mechanism of DDT. Semi-quantitative and hierarchical cluster analysis of compounds in soil showed that the distribution of contaminants in soil was influenced by the types of pollution sources and distance to them. Twenty-two contaminants were found in the soil at relatively high concentrations. The toxicities of 17 of these compounds are currently not known. These results improve our understanding of the environmental behavior of organochlorine contaminants in soil and are useful for further risk assessments of agrochemical-contaminated areas.

Targeted Method for Quantifying Air-Borne Pesticide Residues from Conventional Seed Coat Treatments to Better Assess Exposure Risk During Maize Planting.

Agricultural seed-coat treatments are prone to drift as seed coatings may scuff off and become incorporated into field particles during planting. Vacuum planters release exhaust and kick up field dust, laden with systemic pesticides that blow across the landscape, is taken up, and later expressed in the nectar and pollen of surrounding plants. Offsite movements and nontarget exposure to systemic pesticides need attention and determining how and at what exposure levels pollinators are exposed is of critical importance. Unfortunately, this requires extensive and costly instrumental analyses. Here, we describe dust sampling and a modified, rapid method based on liquid chromatography in tandem with mass spectrometry-based method for quantification of a broad array of agrochemicals in captured dust particles. This method increases ability to detect potential exposure to multiple agrochemicals and allows researchers to better address critical knowledge gaps in the environmental fate, off-target movement, and persistence of conventional seed treatments.

Hexachloropentadiene in Soil, Air, and Biota Around an Agrochemical Factory: Concentrations, Distribution, and Risk Evaluation.

Hexachloropentadiene (HCPD) is a highly toxic compound that is mainly used for preparation of organochlorine insecticides. To investigate HCPD contamination of the environment during pesticide processing, 153 air, soil, and biota samples were collected around an agrochemical factory in different seasons of 1 year and analyzed for HCPD. The HCPD concentrations were 0.01-12.7 ng/m3 (average 2.60 ng/m3) in the air samples and 0.14-51.5 ng/g (average 4.11 ng/g) in the soil samples. HCPD concentrations were highest within 1 km north of the production site, which was in the downwind direction of the factory and storage tanks, especially in autumn and winter. Soil-air exchange analysis showed that HCPD was deposited from air to soil with a flux of 0.003 to 0.20 ng/(m2 d) throughout the year. The dismantling of obsolete equipment accelerated the release of HCPD into the air and increased the amount of HCPD deposited in the soil. HPCD concentration ranges were 0.44-55.7 ng/g dry weight [d.w.] (average 22.2 ng/g d.w.) and 6.69-91.4 ng/g d.w. (average 26.2) in locally grown rice and wheat, respectively. The concentration range was 12.1-1596 ng/g lipid weight (average 560 ng/g lipid weight) in local organisms, except for chicken. In tissues from locally raised chicken, the HCPD concentrations decreased in the order of gizzard, liver, heart, and meat. HCPD was amplified through a short food chain (soil, Vigna unguiculata leaves, larvae of Pieris rapae, and chicken), and the bioaccumulation factor gradually increased over a range of 1.19-25.1 (mean 9.81).

Evaluating the impact of turbidity, precipitation, and land use on nutrient levels and atrazine concentrations in Illinois surface water as determined by citizen scientists.

The objective of this study was to evaluate the impact of turbidity, precipitation, land use, and five-week variation on nutrient levels and atrazine concentrations across Illinois state. To acquire the greatest number of samples in a cost and time-sensitive manner, data were collected by citizen scientists. Volunteers collected data regarding five water quality metrics: nitrites, nitrates, phosphates, atrazine, and turbidity once per week from April 19 until May 17, 2017. A subset (24 %) of volunteers also collected turbidity measurements. Data regarding precipitation was obtained from the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS), a long-standing grassroots volunteer network of backyard weather observers. Three ordinal regression analyses were performed: one without a blocking effect, a second with week as a blocking effect, and a third with watershed as a blocking effect. In all cases, turbidity was significantly associated with elevated levels of nitrate (Pseudo R2-0.48 to 0.94) and phosphate (Pseudo R2-0.60 to 0.80), while precipitation was significantly associated with elevated levels of nitrate (Pseudo R2-0.25 to 0.35). While analyzing five-week variation, the nitrite and nitrate levels, but not phosphate or atrazine, tended to increase at each site. Further, nitrite and nitrate levels significantly varied between the four land uses - agricultural, urban, suburban, and park. When data were analyzed by the three most well-sampled watersheds, Kankakee, Des Plaines, and Chicago, it was identified that the nutrient levels in the Kankakee and Chicago watersheds were significantly elevated relative to the Des Plaines watershed. Finally, cluster analysis identified that clusters dominated by agricultural land, and to a lesser extent suburban land use, had the most elevated nutrient concentration and the greatest frequency of atrazine hits. Data collected by citizen scientists can provide insight into the geospatial variability of nutrients and agrichemicals and can do so across large geographies.

Exposure assessment of 170 pesticide ingredients and derivative metabolites in people from the Central Andes of Peru.

The Central Andes of Peru are a region of great concern regarding pesticide risk to the health of local communities. Therefore, we conducted an observational study to assess the level of pesticide contamination among Andean people. Analytical chemistry methods were used to measure the concentrations of 170 pesticide-related compounds in hair samples from 50 adult Andean subjects living in rural and urban areas. As part of the study, a questionnaire was administered to the subjects to collect information regarding factors that increase the risk of pesticide exposure. Our results indicate that Andean people are strongly exposed to agrochemicals, being contaminated with a wide array of pesticide-related compounds at high concentration levels. Multivariate analyses and geostatistical modeling identified sociodemographic factors associated with rurality and food origin that increase pesticide exposure risk. The present study represents the first comprehensive investigation of pesticide-related compounds detected in body samples collected from people living in the Central Andes of Peru. Our findings pinpoint an alarming environmental situation that threatens human health in the region and provide a rationale for improving public policies to protect local communities.

Targeted Carbon Nanostructures for Chemical and Gene Delivery to Plant Chloroplasts.

Nanotechnology approaches for improving the delivery efficiency of chemicals and molecular cargoes in plants through plant biorecognition mechanisms remain relatively unexplored. We developed targeted carbon-based nanomaterials as tools for precise chemical delivery (carbon dots, CDs) and gene delivery platforms (single-walled carbon nanotubes, SWCNTs) to chloroplasts, key organelles involved in efforts to improve plant photosynthesis, assimilation of nutrients, and delivery of agrochemicals. A biorecognition approach of coating the nanomaterials with a rationally designed chloroplast targeting peptide improved the delivery of CDs with molecular baskets (TP-ß-CD) for delivery of agrochemicals and of plasmid DNA coated SWCNT (TP-pATV1-SWCNT) from 47% to 70% and from 39% to 57% of chloroplasts in leaves, respectively. Plants treated with TP-ß-CD (20 mg/L) and TP-pATV1-SWCNT (2 mg/L) had a low percentage of dead cells, 6% and 8%, respectively, similar to controls without nanoparticles, and no permanent cell and chloroplast membrane damage after 5 days of exposure. However, targeted nanomaterials transiently increased leaf H2O2 (0.3225 µmol gFW-1) above control plant levels (0.03441 µmol gFW-1) but within the normal range reported in land plants. The increase in leaf H2O2 levels was associated with oxidative damage in whole plant cell DNA, a transient effect on chloroplast DNA, and a decrease in leaf chlorophyll content (-17%) and carbon assimilation rates at saturation light levels (-32%) with no impact on photosystem II quantum yield. This work provides targeted delivery approaches for carbon-based nanomaterials mediated by biorecognition and a comprehensive understanding of their impact on plant cell and molecular biology for engineering safer and efficient agrochemical and biomolecule delivery tools.

Pesticide Informatics Platform (PIP): An International Platform for Pesticide Discovery, Residue, and Risk Evaluation.

Pesticides are widely used agrochemicals for crop protection. The need for novel pesticides becomes urgent as a result of the emergence of resistance and environmental toxicity. Pesticide informatics has been applied in different phase processes of pesticide target identification, active ingredient design, and impact evaluation. However, these valuable resources are scattered over the literature and web, limiting their availability. Here, we summarize and connect research on pesticide informatics resources. A pesticide informatics platform (PIP) was constructed to share these tools. We finally discuss the future direction of pesticide informatics, including pesticide contamination. We expect to share the pesticide informatics approaches and stimulate further research.

A Review on Characterization Techniques for Carbon Quantum Dots and Their Applications in Agrochemical Residue Detection.

Carbon quantum dots (CQDs) have emerged as one of the most promising nanomaterials in the carbon nanostructures family in recent years due to their low toxicity, simple synthetic methods, unique fluorescence emission, good photostability, excellent water solubility, high specific surface areas and outstanding electronic properties. They have thus been employed in a wide range of applications, including fluorescent sensing, electrochemical sensing, bioimaging, drug delivery, antimicrobial studies, antioxidants, and photocatalysis. CQDs drawn great interest in sensing applications due to their unique photochemical, electrochemical and electrochemiluminescence properties. They exhibit excitation wavelength-dependent or -independent photoluminescence (PL) behaviour, high quantum yield, and promising binding ability with analytes, which make them an ideal candidate for use in PL based sensing platforms. Excessive use of agrochemicals in farm fields can pollute the environment and have potentially adverse health effects on aquatic and human life. Since there are very few monitoring techniques are available for sensing such harmful substances, there is an urgent need to develop a sensor for the facile, rapid and on-site detection and quantification of agrochemical residues in the environment. Several CQD-based fluorophores for detecting agrochemical residues employing static or dynamic quenching processes have recently been published. The key quenching mechanisms involved in the sensing process include FRET, PET and IFE. The first part of this review intends to provide a comprehensive overview of various techniques to characterize CQDs such as UV-vis., FT-IR, PL, XRD, NMR, TEM, TGA, XPS and Raman analysis. In addition application of CQDs as fluorescent sensors for agrochemical residue in different media are summarized in this reiew. The LOD values and rapid action of the sensor demonstrates significant advantages of these methods over conventional analytical procedures.

Detection of enteropathogens and research of pesticide residues in Lactuca sativa from traditional and agroecological fairs / Detecção de enteropatógenos e pesquisa de resíduos de agrotóxicos em Lactuca sativa de feiras tradicionais e agroecológicas

Agroecological production represents a new reality in vegetable farming. Thus, the study aimed to search for the presence of pesticides in agroecological samples and microbiological and parasitological contamination in Lactuca sativa L. of agroecological and conventional fairs in Alagoas. Thirty-two samples were collected, a hygienic sanitary checklist was performed, along with coliform, Salmonella spp., Staphylococcus aureus research and Gas Chromatography with Mass Spectrometer (GC-MS) for pesticide research; using two methodologies for parasitological studies. Thirty-two samples were analyzed, with a sanitary adequacy level at 45% and 38% for fairs (agroecological and conventional) respectively, with three samples (9.4%) in total, being adequate to the microbiological pattern according to RDC no. 12/2001. Among the 23 samples which were tested positive for parasites, 69.5% originated from samples extracted at conventional fairs, and 53% of every positive samples presented Entamoeba coli as the main contaminant. All together, no traces of deltamethrin were detected, but in two of the samples a peak retention for diphenoconazole was detected. In conclusion, the fairs represent an adequate environment for human pathogens and indicators. Therefore greater hygiene training of vegetable traders and consumers in the state of Alagoa sis required, especially in conventional fairs, which presented more critical microbiological and parasitological indexes comparing to fairs with agroecological products; however, the presence of difenoconazole in two samples of agricultural fairs suggests accidental contamination or indiscriminate use of this chemical in the production of Lactuca sativa, however, products with agroecological origin represents a better choice for the consumers.

A produção agroecológica representa uma nova realidade no cultivo das hortaliças. Assim, o estudo teve como objetivo verificar a presença de agrotóxicos em amostras agroecológicas e analisar a contaminação microbiológico e parasitológico em Lactuca sativa L. de feiras agroecológicas e convencionais de Alagoas. Foram coletadas 32 amostras, realizando checklist higiênico-sanitário, análises de coliformes, Salmonella spp., Staphylococcus aureus e Cromatografia Gasosa com Espectrômetro de Massas (GC-MS) para pesquisa de agrotóxicos; utilizando-se duas metodologias para estudos parasitológicos. Foram analisadas 32 amostras, com nível de adequação sanitária de 45% e 38% para feiras (agroecológicas e convencionais) respectivamente, sendo três amostras no total (9,4%) adequadas a padrão microbiológico segundo RDC n° 12//2001; Dentre as 23 amostras positivas para parasitos, 69,5% teve origem em amostras de feiras convencionais, e 53% de todas as amostras positivas apresentaram Entamoeba coli como principal contaminante, juntamente, não foi detectado traços de deltametrina, porem foi visualizado em duas amostras, pico de retenção para padrão de difenoconazol. Concluindo-se que as feiras representam um ambiente adequado para patógenos humanos e indicadores, necessitando de uma maior higienização e treinamento dos comerciantes e consumidores de hortaliças do estado de Alagoas, principalmente em feiras convencionais, que apresentaram índices microbiológicos e parasitológicos mais críticos em relação a feiras com produtos agroecológicos; mas, a presença de difenoconazole em duas amostras de feiras agroecológicas sugerem contaminação acidental ou uso indiscriminado deste químico em produção da Lactuca sativa L., todavia os produtos de origem agroecológica representam uma melhor escolha para o consumidor.

Correlation between dietary and dislodgeable foliar (DFR) crop residues decline data; A proposed approach to refine non-dietary risk assessment.

Pesticide residues in crop plants are routinely measured in an edible commodity or in feed items to determine safe use. Pesticides present as dislodgeable foliar residues (DFR) are measured for use in non-dietary risk assessments where worker, resident and bystander re-entry may lead to contact with the treated foliage. Possible correlations between dietary and DFR residue decline have been investigated considering data from 177 dietary residue trials along with 56 DFR trials from outdoor studies on the same crops besides residue decline data available in the Plant Properties Database (PPDB).The residue studies proved to follow the non-normal distribution and the comparison between DT50 of both types of residues for all the active substances revealed higher numerical DT50 mean values of the dietary residue compared to the DFRs. The dissipation from dietary residue studies is slower with a higher population mean compared to the mean for DFR studies for most active substances studied. A DT50 value from dietary residue studies could potentially act as a conservative surrogate DT50 for DFR which could be useful in determining the length of DFR studies and benefit both the agrochemical industry and the regulatory bodies in supporting non-dietary pesticide risk assessment.

Biochar for remediation of agrochemicals and synthetic organic dyes from environmental samples: A review.

Application of agrochemicals in farming sector to control insects and pests; and use of synthetic organic dyes to color the products are increasing continuously due to the rapid growth of industries. During the application process many industries releases toxic agrochemicals and dyes in to the aquatic environment and on land without the proper treatment. Due to their toxicity the disposal of such chemicals is of utmost importance. Biochar offers the ability to remediate these substances from environmental matrices because of their high sorption ability of pollutants from water and soil. This review highlights the development and advancement of biochar-based treatment for abatement of agrochemicals and synthetic organic dyes, involving its technical aspects and the variables connected with removing these kinds of pollutants. Several optimization parameters like temperature, pH, chemical concentration, biochar properties, time, and co-existing ions have been elaborated. Literature survey shows that most of the researches on biochar application have been conducted in the batch mode. Hence there is an urgent need to apply this beneficial technique for the remediation of pollutants at the larger scale in the real water and soil samples. A comprehensive summary on sorption kinetics and adsorption isotherms with regards to pollutant removal is also presented. This review also covers the cost analysis of various techniques where biochar has been used as an adsorbent. Thus this review makes an easy roadmap for the further development in biochar and biochar based composites and expansion of these demanding areas of research in biochar and their applications.

Ambient (desorption/ionization) mass spectrometry methods for pesticide testing in food: a review.

Ambient mass spectrometry refers to the family of techniques that allows ions to be generated from condensed phase samples under ambient conditions and then, collected and analysed by mass spectrometry. One of their key advantages relies on their ability to allow the analysis of samples with minimal to no sample workup. This feature maps well to the requirements of food safety testing, in particular, those related to the fast determination of pesticide residues in foods. This review discusses the application of different ambient ionization methods for the qualitative and (semi)quantitative determination of pesticides in foods, with the focus on different specific methods used and their ionization mechanisms. More popular techniques used are those commercially available including desorption electrospray ionization (DESI-MS), direct analysis on real time (DART-MS), paper spray (PS-MS) and low-temperature plasma (LTP-MS). Several applications described with ambient MS have reported limits of quantitation approaching those of reference methods, typically based on LC-MS and generic sample extraction procedures. Some of them have been combined with portable mass spectrometers thus allowing "in situ" analysis. In addition, these techniques have the ability to map surfaces (ambient MS imaging) to unravel the distribution of agrochemicals on crops.

Treatment of agrochemical wastewater by subcritical water oxidation method: chemical composition and ion analysis of treated and untreated samples.

This work aimed at offering an effective and environmentally friendly approach to the real wastewater of an industrial agrochemicals production plant containing high amounts of many hazardous compounds that threaten human health. The removal of total organic carbon (TOC) (59.45%) and colour (97.92%) of the wastewater was achieved using subcritical water oxidation method. The fate of the detected compounds was followed by GC-MS analysis. Several pollutants such as phenol, fumaric acid, chlorpyrifos, penconazole, brassilexin, buprofezin, etoxazole, pyriproxyfen and 2-naphthalene-sulphonic acid which are bio-refractory and harmful to human health, were effectively degraded. Inorganic ions exist in the wastewater or formed through the process and their possible effects on the applied method were analysed. The central composite design was used to optimise the method and fully evaluate the single or combined effects of the method parameters on the removal rates. The precision of the applied design models was evaluated employing ANOVA, Regression coefficients and validation analysis. F and P and R2 values were obtained as 107.43, <0.0001, and 0.9898, respectively in the TOC removal model and 39.45, <0.0001, and 0.9726 in the colour removal model.[Formula: see text].

Dissipation and residue determination of penicillin G and its two metabolites in citrus under field conditions by DSPE/UPLC-MS/MS.

A rapid determination method of residual penicillin G and its two metabolites in citrus was developed and validated by dispersive solid-phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry (DSPE/UPLC-MS/MS). The samples were extracted with 80% acetonitrile and purified with octadecylsilane. High linearity was obtained with correlation coefficients (r2 ) >0.9981. The limits of quantification were 0.005-0.01 mg/kg. The recoveries of penicillin G and its metabolites spiked in blank citrus were within 76.7-107%, with relative standard deviations of 1.3-9.6%. The dissipation dynamics and distribution of penicillin G in citrus followed first-order kinetics, with half-life of 1.7-2.7 days. Penicillin G degraded easily in citrus and the metabolite was mainly penilloic acid, which can exist stably for long time. The terminal residues of penicillin G in pulp, whole citrus and peels were 0.015-0.701, 0.047-7.653 and 0.162-13.376 mg/kg, respectively. The hazard indexes for risk assessment of citrus were significantly <1, suggesting that the health risks to humans after consumption of citrus were insignificant and negligible. These results could provide necessary data for evaluating the safe and proper use of penicillin G in citrus.

Chronic kidney disease and household behaviors in Sri Lanka: Historical choices of drinking water and agrochemical use.

This paper examines whether there are systematic differences in the historical behaviors of households that are affected and unaffected by chronic kidney disease (CKD) in Sri Lanka pertaining to their water source choices, water treatment practices, and agrochemical use. This analysis is motivated by the Sri Lankan government's largest policy response to this epidemic - to encourage communities to switch from untreated well water to publicly provided alternatives. We use recall methods to elicit information on the drinking water source and treatment choices of households over an 18-year period from 2000-2017. Our analysis is based on a survey of 1497 rural ground-water dependent households in the most CKD-affected areas of the 10 districts of Sri Lanka with the highest prevalence of CKD. Our main findings are that (a) households that have ever used a pump to extract (typically deep) drinking water from a household well are more likely to be affected by CKD; (b) we fail to find a relationship between disease status and households' use of buckets to extract (typically shallow) groundwater from their wells; and (c) those who have ever treated their shallow well water by boiling it are less likely to be affected by CKD. We also find that a greater share of CKD affected households historically used agrochemicals, used wells that were geographically removed from surface water sources, and displayed lower proxies of wealth. The implications of these findings are fourfold. First, since the systematic differences in the historical patterns of water sources and treatments used by CKD affected and non-affected households are modest, the sources of water and the treatment practices themselves may not be the sole risk factors in developing CKD. Second, although we find a negative association between boiling water and the probability of CKD, it is not obvious that a public policy campaign to promote boiling water is an appropriate response. Third, the hydrochemistry of deep and shallow well water needs to be better understood in order to shed light on the positive relationship between deep well water and disease status, and on why boiling shallow but not deep well water is associated with a lower probability of CKD. Fourth, there is a need for a deeper understanding of other risk factors and of the efficacy of preventative programs that provide alternative sources of household drinking water.