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In plasticulture production systems, the conventional practice involves broadcasting pre-emergent herbicides over the entire surface of raised beds before laying plastic mulch. However, weed emergence predominantly occurs through the transplant punch-holes in the mulch, leaving most of the applied herbicide beneath the plastic, where weeds cannot grow. To address this issue, we developed and evaluated a precision spraying system designed to target herbicide application to the transplant punch-holes. A dataset of 3378 images was manually collected and annotated during a tomato experimental trial at the University of Florida. A YOLOv8x model with a p2 output layer was trained, converted to TensorRT® to improve the inference time, and deployed on a custom-built computer. A Python-based graphical user interface (GUI) was developed to facilitate user interaction and the control of the smart sprayer system. The sprayer utilized a global shutter camera to capture real-time video input for the YOLOv8x model, which activates or disactivates a TeeJet solenoid for precise herbicide application upon detecting a punch-hole. The model demonstrated excellent performance, achieving precision, recall, mean average precision (mAP), and F1score exceeding 0.90. Field tests showed that the smart sprayer reduced herbicide use by up to 69% compared to conventional broadcast methods. The system achieved an 86% punch-hole recognition rate, with a 14% miss rate due to challenges such as plant occlusion and variable lighting conditions, indicating that the dataset needs to be improved. Despite these limitations, the smart sprayer effectively minimized off-target herbicide application without causing crop damage. This precision approach reduces chemical inputs and minimizes the potential environmental impact, representing a significant advancement in sustainable plasticulture weed management.

Objectives Rapid evolution and progress in computer sciences present new determinants for informational technologies. The universal knowledge based on Mathematics and Computer science exploring processes in information dissemination, should be persistently analyzed. Its focus on practical applicability presents various problems and new possibilities for the field of Security Studies, adding new categories to its research interests, that should be constantly defined and redefined. And what is the objective of the article. Material and methods The descriptive methodology used in the article is limited to a presentation of philosophical categories, as it allows for defining of chosen problems that correspond, upon analysis, to asymmetric threats mounting from IT evolution. Results The predicaments of technological evolution in view o the categories arising through philosophical focus, presented here by authors and as applied in Security studies, point to definitions and associated categories of potential dangers that IT progress may entail. Hence, the presentation of three categories analyzed – information, communication, asymmetric threat, and the following analysis of categories of threats with asymmetric values, as a potential nuisance and danger to state security, related to those categories. Conclusions And as is concluded, the new developments, as discussed in the article, present challenges for state security and are presently evolving. Hence, those should be constantly categorized and associated with security predicaments – active and potential.

The field cricket, Scapsipedus icipe Hugel and Tanga (Orthoptera: Gryllidae) is edible and could be used to reduce malnutrition in Sub-Saharan Africa. As the demand for cricket products is increasing, there is a need to find cost-effective ways of rearing this cricket using locally available and affordable sources of food. This study evaluated the feeding preferences of the field cricket S. icipe for 11 species of dayflowers (Commelina spp.; Commelinaceae), using no-choice and multiple-choice experiments in controlled environments. Leaf feeding rates and the nutrient content and phytochemicals of the plants were determined. The ANOVA results indicate significantly higher feeding rates when offered Commelina petersii and C. forskaolii, than Commelina sp. and C. purpurea in no-choice experiments. Multiple-choice experiments ranked C. petersii as the most preferred species followed by C. forskaolii and the two reference species, C. benghalensis var. benghalensis (non-hybrid variant) and C. benghalensis (hybrid variant). The Spearman correlation and PCA revealed positive significant associations between leaf feeding and Ca and NDF content of leaves and a negative significant association between Ca and NDF. A high Ca/low NDF content was recorded for C. petersii and a low Ca/high NDF content for C. purpurea. The beta regression analysis and a biplot identified six phytochemical constituents influencing leaf feeding: phenols, alkaloids, tannins, glycosides, saponins and anthraquinones. Phenols stimulate feeding by S. icipe on C. petersii and C. forskaolii, whereas the tannins and alkaloids in Commelina sp. and C. purpurea, acted as deterrents. Nutrient content and phytochemicals are two important factors determining the suitability of species of Commelina for the field cricket S. icipe. Based on the results of this study, the leaves of C. petersii are highly recommended as a source of food for the mass rearing of this field cricket (S. icipe) and boosting entomophagy in Sub-Saharan Africa.

Industrial tests of fibrous filters have shown that, above mist drop collecting, they are effective means for adsorption of gaseous impurities. Considering it, there were made tests that enabled reaching quantitative results on CO2 absorption by aqueous solution of sodium. Tests were made on experimental plant using apparatus with fibrous nozzle as its main element. Absorber studies were made in the laboratory of engineering ecology of municipal services at Moscow State University of Environmental Engineering (MSUEE). Experimental plant is automated: controlling and regulation of regime parameters of the absorber are made using the monitor of a personal computer. Santrauka Atlikus pluoštiniu filtru pramoninius tyrimus nustatyta, kad šie filtrai, laikomi virš ruko lašeliu, efektyviai adsorbuoja dujose esancius nešvarumus. Atsižvelgiant i tai buvo atliekami tyrimai su natrio šarmo tirpalu ir gauti kiekybiniai CO2 absorbcijos rezultatai. Tirta eksperimentinimis salygomis naudojant prietaisus su pluoštiniu antgaliu. Absorberio tyrimai buvo atliekami Miestu inžinerinis ekologijos laboratorijoje Maskvos valstybiniame aplinkos inžinerijos universitete (AIMVU). Eksperimentinis tyrimas automatizuotas, absorberio režimo parametrai kontroliuojami ir reguliuojami asmeniniu kompiuteriu. Резюме Промышленные испытания волокнистых фильтров показали, что помимо улавливания капель туманов, они достаточно эффективно поглощают и газообразные вредности. В связи с этим на экспериментальной установке, основным элементом которой являлся аппарат с волокнистой насадкой, были проведены исследования, позволившие получить количественные результаты по абсорбции СО2 водным раствором соды. Исследования абсорбера проводились в лаборатории кафедры «Инженерная экология городского хозяйства» Московского государственного университета инженерной экологии (МГУИЭ). Экспериментальная установка автоматизирована: контроль и регулировка режимных параметров абсорбера осуществляются с экрана персонального компьютера. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: pluoštinis dangtelis, hidraulinis pasipriešinimas, absorbcija Ключевые слова: волокнистая насадка, гидравлическое сопротивление, абсорбция.

The paper gives theoretic analysis and results of experimental investigation of suspended particle collecting in high‐speed fibrous mist collectors. A dominating role of inertial mechanism of suspended particle precipitation in highspeed mist collectors was determined and a method of calculation of their efficiency by means of probability integral was proposed. Applicability of physical analogy method to deduction of dependency determining values of d50 (diameter of particles collected in an apparatus under given technological mode of its operation with the efficiency of 50 %) on the basis of experimental data is shown. Experimental assembly used for research, testing techniques and result estimating methods are described. Investigation results allowed achieving an improved formula for calculating the value of d50 depending on hydraulic resistance of apparatus and density of collected particles. Suspenduotų dalelių inertinio nusodinimo didelio greičio pluošiniuose filtruose efektyvumas Santrauka Pateikta suspenduotų dalelių surinkimo didelio greičio pluoštiniu aerozolių filtru eksperimentinių tyrimų teorinė analizė ir rezultatai. Apibrėžta dominuojanti suspenduotų dalelių inercijos svarba didelio greičio surinktuvuose ir pasiūlytas skaičiavimo metodas, paremtas filtrų efektyvumo nustatymu integruojant tikimybes. Pateikta galimybė pritaikyti fiziniu aspektu analogišką metodą nustatant priklausomybę, išreiškiančią d50 dalelių (dalelių, kurios surenkamos nurodytu režimu dirbančiame įrenginyje 50 % efektyvumu, skersmuo) vertes remiantis eksperimentiniais duomenimis. Pateiktas tyrimams ir testavimui skirto eksperimentinio agregato aprašymas ir rezultatų skaičiavimo metodai. Tyrimo rezultatai leido patobulinti formulę d50 vertėms apskaičiuoti atsižvelgiant į hidraulinį aparato pasipriešinimą ir surinktų dalelių tankį. Reikšminiai žodžiai: pluoštinis filtras, automatinio modelio veika, inertinio nusodinimo efektyvumas. Эффективность инерционного осаждения взвешенных частиц в высокоскоростных волокнистых фильтрах Резюме Приводится теоретический анализ и результаты экспериментального исследования улавливания взвешенных частиц в высокоскоростных волокнистых туманоуловителях. Установлена доминирующая роль инерционного механизма осаждения взвешенных частиц в высокоскоростных туманоуловителях, и предложен метод расчета их эффективности с помощью интеграла вероятности. Показана возможность использования метода физической аналогии для вывода зависимости, определяющей на основании экспериментальных данных значения величины d50 (диаметр частиц, улавливаемых в аппарате при данном технологическом режиме его работы с эффективностью 50 %). Описана экспериментальная установка, на которой проводились исследования, приведены методики проведения опытов и оценки их результатов. Результаты исследований позволили получить уточненную формулу для расчета величины d50 в зависимости от гидравлического сопротивления аппарата и плотности улавливаемых частиц. Ключевые слова: волокнистый фильтр, автомодельный режим, эффективность инерционного осаждения. First Published Online: 14 Oct 2010

Abstract Background In mammals, males typically have shorter lives than females. This difference is thought to be due to behavioural traits which enhance competitive abilities, and hence male reproductive success, but impair survival. Furthermore, in many species males usually show higher parasite burden than females. Consequently, the intensity of selection for genetic factors which reduce susceptibility to pathogens may differ between sexes. High variability at the major histocompatibility complex (MHC) genes is believed to be advantageous for detecting and combating the range of infectious agents present in the environment. Increased heterozygosity at these immune genes is expected to be important for individual longevity. However, whether males in natural populations benefit more from MHC heterozygosity than females has rarely been investigated. We investigated this question in a long-term study of free-living Alpine chamois (Rupicapra rupicapra), a polygynous mountain ungulate. Results Here we show that male chamois survive significantly (P = 0.022) longer if heterozygous at the MHC class II DRB locus, whereas females do not. Improved survival of males was not a result of heterozygote advantage per se, as background heterozygosity (estimated across twelve microsatellite loci) did not change significantly with age. Furthermore, reproductively active males depleted their body fat reserves earlier than females leading to significantly impaired survival rates in this sex (P < 0.008). This sex-difference was even more pronounced in areas affected by scabies, a severe parasitosis, as reproductively active males were less likely to survive than females. However, we did not find evidence for a survival advantage associated with specific MHC alleles in areas affected by scabies. Conclusions Increased MHC class II DRB heterozygosity with age in males, suggests that MHC heterozygous males survive longer than homozygotes. Reproductively active males appear to be less likely to survive than females most likely because of the energetic challenge of the winter rut, accompanied by earlier depletion of their body fat stores, and a generally higher parasite burden. This scenario renders the MHC-mediated immune response more important for males than for females, which implies a relatively stronger selection pressure on MHC genes in males than in females.

Abstract Background Corynebacterium aurimucosum is a slightly yellowish, non-lipophilic, facultative anaerobic member of the genus Corynebacterium and predominantly isolated from human clinical specimens. Unusual black-pigmented variants of C. aurimucosum (originally named as C. nigricans) continue to be recovered from the female urogenital tract and they are associated with complications during pregnancy. C. aurimucosum ATCC 700975 (C. nigricans CN-1) was originally isolated from a vaginal swab of a 34-year-old woman who experienced a spontaneous abortion during month six of pregnancy. For a better understanding of the physiology and lifestyle of this potential urogenital pathogen, the complete genome sequence of C. aurimucosum ATCC 700975 was determined. Results Sequencing and assembly of the C. aurimucosum ATCC 700975 genome yielded a circular chromosome of 2,790,189 bp in size and the 29,037-bp plasmid pET44827. Specific gene sets associated with the central metabolism of C. aurimucosum apparently provide enhanced metabolic flexibility and adaptability in aerobic, anaerobic and low-pH environments, including gene clusters for the uptake and degradation of aromatic amines, L-histidine and L-tartrate as well as a gene region for the formation of selenocysteine and its incorporation into formate dehydrogenase. Plasmid pET44827 codes for a non-ribosomal peptide synthetase that plays the pivotal role in the synthesis of the characteristic black pigment of C. aurimucosum ATCC 700975. Conclusions The data obtained by the genome project suggest that C. aurimucosum could be both a resident of the human gut and possibly a pathogen in the female genital tract causing complications during pregnancy. Since hitherto all black-pigmented C. aurimucosum strains have been recovered from female genital source, biosynthesis of the pigment is apparently required for colonization by protecting the bacterial cells against the high hydrogen peroxide concentration in the vaginal environment. The location of the corresponding genes on plasmid pET44827 explains why black-pigmented (formerly C. nigricans) and non-pigmented C. aurimucosum strains were isolated from clinical specimens.

This article describes the experience of a large academic library with headings in the OCLC database that have been converted to AACR2 form. It also considers the use of LC authority records in the database. Specific problems are discussed, including some resulting from LC practices. Nevertheless, the presence of the authority records, and especially the conversionof about 40 percent of the headings in the bibliographic file, has been of great benefit to the library, significantly speeding up the cataloging operation. An appendix contains guidelines for the cataloging staff of theUniversity of Illinois, Urbana-Champaign in the interpretation and use of LC authority records and converted headings.

Recent regulations on perfluorinated compounds in drinking water underscore the need for a deeper understanding of the formation of perfluorinated compounds from polyfluoroalkyl substances during chlorine disinfection. Among the compounds investigated in this study, N-(3-(dimethylaminopropan-1-yl)perfluoro-1-hexanesulfonamide (N-AP-FHxSA) underwent rapid transformation during chlorination. Within an hour, it produced quantitative yields of various poly- and per-fluorinated products, including perfluorohexanoic acid (PFHxA). Sixteen reactions involving chlorine with N-AP-FHxSA and its quaternary ammonium analog were investigated; seven were confirmed, while the remainder were either disproved or found to be insignificant. The quaternary ammonium moiety did not determine a polyfluoroalkyl substance's reactivity toward chlorine. For example, while 6:2 fluorotelomer sulfonamide betaine transformed rapidly to PFHxA, other quaternary-ammonium-containing polyfluoroalkyl substances, such as 5:1:2 and 5:3 fluorotelomer betaines, showed significant resistance to chlorination. Further investigation identified potential sites for electrophilic attacks near the amine region by examining the highest occupied molecular orbitals of the polyfluoroalkyl substances. Visualization techniques helped pinpoint electron-deficient and electron-rich sites as potential targets for nucleophilic and electrophilic attacks, respectively. Increasing the solution pH from 6 to 10 did not diminish the apparent degradation of the studied polyfluoroalkyl substances, likely due to the greater reactivity of the deprotonated forms compared to the conjugate acids. Finally, we also examined the hydrolysis of polyfluoroalkyl substances at pH 6 to 11 in the absence of chlorine.

Due to the widespread use of insecticides in agriculture and for urban pest control, there is the potential for contamination of groundwater systems. Five neonicotinoids, fipronil, and nine transformation products (desnitro-imidacloprid, imidacloprid olefin, imidacloprid urea, acetamiprid-n-desmethyl, thiacloprid amide, 6-chloronicotinic acid, fipronil desulfinyl, fipronil sulfide, and fipronil sulfone) were studied in samples from 15 springs and 75 unique wells from 13 counties over four years (2019-2022) in Minnesota. Up to 13 neonicotinoids and fiproles were identified in groundwater samples from springs and 10 from wells. Springs were particularly susceptible to contamination, with clothianidin found in 41 % of springs (maximum concentration: 200 ng/L) followed by thiamethoxam (31 %), imidacloprid (22 %), thiacloprid (19 %), and acetamiprid (12 %). Clothianidin was the most common analyte in well samples (13 %), followed by thiamethoxam (12 %), acetamiprid (14 %), imidacloprid (10 %), and thiacloprid (2 %). Hydrostratigraphy was an important factor in neonicotinoid detection with frequencies of detection highest in sandy or karst aquifers. Regional land use, especially the fraction of agricultural land, and imperviousness influenced observed concentrations within springsheds and well catchment areas. There were several significant correlations between neonicotinoid detections with geochemistry indicators including tritium/groundwater age, dissolved oxygen (DO), and total nitrate plus nitrite (total oxidized nitrogen)., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: William Arnold reports financial support was provided by Environment and Natural Resources Trust Fund. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study aims to support the prioritization of research and development (R&D) pathways of an anaerobic technology leveraging hydrogel-encapsulated biomass to treat high-strength organic industrial wastewaters, enabling decentralized energy recovery and treatment to reduce organic loading on centralized treatment facilities. To characterize the sustainability implications of early-stage design decisions and to delineate R&D targets, an encapsulated anaerobic process model was developed and coupled with design algorithms for integrated process simulation, techno-economic analysis, and life cycle assessment under uncertainty. Across the design space, a single-stage configuration with passive biogas collection was found to have the greatest potential for financial viability and the lowest life cycle carbon emission. Through robust uncertainty and sensitivity analyses, we found technology performance was driven by a handful of design and technological factors despite uncertainty surrounding many others. Hydraulic retention time and encapsulant volume were identified as the most impactful design decisions for the levelized cost and carbon intensity of chemical oxygen demand (COD) removal. Encapsulant longevity, a technological parameter, was the dominant driver of system sustainability and thus a clear R&D priority. Ultimately, we found encapsulated anaerobic systems with optimized fluidized bed design have significant potential to provide affordable, carbon-negative, and distributed COD removal from high strength organic wastewaters if encapsulant longevity can be maintained at 5 years or above.

The aqueous photolysis of four pharmaceuticals with varying fluorinated functional groups was assessed under neutral, alkaline, advanced oxidation, and advanced reduction conditions with varying light sources. Solar simulator quantum yields were 2.21 × 10 -1  mol Ei -1 for enrofloxacin, 9.36 × 10 -3  mol Ei -1 for voriconazole, and 1.49 × 10 -2  mol Ei -1 for flecainide. Florfenicol direct photolysis was slow, taking 150 h for three degradation half-lives. Bimolecular rate constants between pharmaceuticals and hydroxyl radicals were 10 9 to 10 10  M -1  s -1 . Using a combined quantitative fluorine nuclear magnetic resonance spectroscopy ( 19 F-NMR) and mass spectrometry approach, fluorine mass balances and photolysis product structures were elucidated. Enrofloxacin formed a variety of short-lived fluorinated intermediates that retained the aryl F motif. Extended photolysis time led to complete aryl F mineralization to fluoride. The aliphatic F moiety on florfenicol was also mineralized to fluoride, but the resulting product was a known antibiotic (thiamphenicol). For voriconazole, the two aryl Fs contributed more to fluoride production compared with the heteroaromatic F, indicating higher stability of the heteroaromatic F motif. The two aliphatic CF 3 moieties in the flecainide structure remained intact under all conditions, further supporting the stability of these moieties found in per- and polyfluoroalkyl substances under a variety of conditions. The advanced treatment conditions generating hydroxyl radicals or hydrated electrons accelerated the degradation, but not the defluorination, of flecainide. The combination of 19 F-NMR and mass spectrometry proved powerful in allowing identification of fluorinated products and verifying the functional groups present in the intermediates and products. The results found in the present study will aid in the understanding of which fluorinated functional groups should be incorporated into pharmaceuticals to ensure organofluorine byproducts are not formed in the environment and help determine the water-treatment processes that effectively remove specific pharmaceuticals and more generally fluorinated motifs. Environ Toxicol Chem 2024;43:2285-2296. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Fluorinated breakdown products from photolysis of pharmaceuticals and pesticides are of environmental concern due to their potential persistence and toxicity. While mass spectrometry workflows have been shown to be useful in identifying products, they fall short for fluorinated products and may miss up to 90% of products. Studies have shown that 19 F NMR measurements assist in identifying and quantifying reaction products, but this protocol can be further developed by incorporating computations. Density functional theory was used to compute 19 F NMR shifts for parent and product structures in photolysis reactions. Computations predicted NMR spectra of compounds with an R 2 of 0.98. Computed shifts for several isolated product structures from LC-HRMS matched the experimental shifts with <0.7 ppm error. Multiple products including products that share the same shift that were not previously reported were identified and quantified using computational shifts, including aliphatic products in the range of -80 to -88 ppm. Thus, photolysis of fluorinated pharmaceuticals and pesticides can result in compounds that are polyfluorinated alkyl substances (PFAS), including aliphatic-CF 3 or vinyl-CF 2 products derived from heteroaromatic-CF 3 groups. C-F bond-breaking enthalpies and electron densities around the fluorine motifs agreed well with the experimentally observed defluorination of CF 3 groups. Combining experimental-computational 19 F NMR allows quantification of products identified via LC-HRMS without the need for authentic standards. These results have applications for studies of environmental fate and analysis of fluorinated pharmaceuticals and pesticides in development.

N -nitrosodimethylamine (NDMA) precursor concentrations along four major rivers in Minnesota, USA were quantified and correlated with watershed land cover types, anthropogenic activity, and organic matter characteristics. River water samples (36 in total) were chloraminated under uniform formation conditions (UFC) before and after lime-softening treatment, and the resulting NDMA concentrations were quantified (NDMA UFC ). Regarding land cover, NDMA UFC in raw river water exhibited weak positive correlations with urban land (ρ = 0.33, p = 0.05) and cropland coverage (ρ = 0.35, p = 0.04). For anthropogenic activity, NDMA UFC in raw river water positively correlated with the number of feedlots (ρ = 0.57), total weight of animals (ρ = 0.68), and total number of domestic wastewater treatment plants (WWTPs; ρ = 0.63) with p < 0.01. NDMA UFC positively correlated with region IV fluorescence intensity from fluorescence excitation-emission spectra (ρ = 0.70, p < 0.01). Lime softening of river water typically increased NDMA UFC and preferentially removed organic matter that fluoresces in region V, suggesting that the organic matter in this region decreases NDMA UFC by competing for available chloramines. Overall, animal feedlots, along with domestic WWTPs, are predominant sources of NDMA precursors in the studied watersheds, while croplands and urban runoff are of lesser importance.

Quaternary ammonium compounds (QACs) are used in consumer and industrial products, including disinfectants. Due to the COVID-19 pandemic, disinfectant use has increased, purportedly increasing loads to wastewater treatment plants and the environment. To understand how the increased usage has affected QAC loadings to treatment plants and to determine how effectively plants remove QACs from liquid effluent that is discharged to surface and groundwaters, influent and effluent wastewater samples were collected from four treatment plants (treatment capacities < 5 MGD to > 100 MGD) for 21 months beginning in May 2020. Influent QAC concentrations were hundreds of μg/L and effluent QAC concentrations were < 1 μg/L, corresponding to an average removal of 98% from all four plants. The most prevalent QACs in influent were those used most commonly in disinfectants, specifically benzylalkyldimethylammonium compounds (BACs) and short-chain dialkyldimethylammonium compounds (DADMACs), and influent levels of these compounds were correlated with QAC sales. Prior to this study, ethylbenzylalkyldimethylammonium compounds (EtBACs) had not been studied, and they comprised 13 ± 6% of QACs in influent. While removal was high at all plants, low μg/L concentrations were still continuously discharged into the environment. For QACs with equivalent alkyl chain lengths, those with aromatic substituents (BACs and EtBACs) appear to be removed more effectively than those with only alkyl chains (DADMACs).

The presence of antibiotics in surface waters is a potential driver of antibiotic resistance and thus of concern to human and environmental health. Key factors driving the potential impact of antibiotics are their persistence and transport in rivers and lakes. The goal of this study was to describe the peer-reviewed published literature on the photolysis (direct and indirect), sorption, and biodegradation of a selected group of antibiotic compounds following a scoping review methodology. Primary research from 2000 to 2021 was surveyed to compile information on these processes for 25 antibiotics from 6 classes. After compilation and assessment of the available parameters, the results indicate that information is present to predict the rates of direct photolysis and reaction with hydroxyl radical (an indirect photolysis process) for most of the selected antibiotics. There is insufficient or inconsistent information for including other indirect photolysis processes, biodegradation, or removal via sorption to settling particles for most of the targeted antibiotic compounds. Future research should focus on collecting fundamental parameters such as quantum yields, second-order rate constants, normalized biodegradation rates, and organic carbon or surface area normalized sorption coefficients rather than pseudo-first order rate constants or sorption equilibrium constants that apply only to specific conditions/sites., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Randall Singer reports financial support was provided by Minnesota Environment and Natural Resources Trust Fund., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The Crow River, a tributary of the Mississippi River in Minnesota, U.S.A., that is impacted by agricultural activities and municipal wastewater discharges, was sampled approximately monthly at 12 locations over 18 months to investigate temporal and spatial variations in N -nitrosodimethylamine (NDMA) precursor levels. NDMA precursors were quantified primarily by measuring NDMA formed under the low chloramine dose uniform formation conditions protocol (NDMA UFC ) and occasionally using the high dose formation potential protocol (NDMA FP ). Raw water NDMA UFC concentrations (2.2 to 128 ng/L) exhibited substantial temporal variation but relatively little spatial variation. An increase in NDMA UFC was observed for 126 of 169 water samples after lime-softening treatment. A kinetic model indicates that under chloramine-limited UFC test conditions, the increase in NDMA UFC can be attributed to a decrease in competition between precursors and natural organic matter (NOM) for chloramines and reduced interactions of precursors with NOM. NDMA UFC concentrations correlated positively with dissolved nitrogen concentration (ρ = 0.44, p < 0.01) when excluding the spring snowmelt period and negatively correlated with dissolved organic carbon concentration (ρ = -0.47, p < 0.01). Overall, NDMA precursor levels were highly dynamic and strongly affected by lime-softening treatment.

Quaternary ammonium compounds (QACs), a large class of chemicals that includes high production volume substances, have been used for decades as antimicrobials, preservatives, and antistatic agents and for other functions in cleaning, disinfecting, personal care products, and durable consumer goods. QAC use has accelerated in response to the COVID-19 pandemic and the banning of 19 antimicrobials from several personal care products by the US Food and Drug Administration in 2016. Studies conducted before and after the onset of the pandemic indicate increased human exposure to QACs. Environmental releases of these chemicals have also increased. Emerging information on adverse environmental and human health impacts of QACs is motivating a reconsideration of the risks and benefits across the life cycle of their production, use, and disposal. This work presents a critical review of the literature and scientific perspective developed by a multidisciplinary, multi-institutional team of authors from academia, governmental, and nonprofit organizations. The review evaluates currently available information on the ecological and human health profile of QACs and identifies multiple areas of potential concern. Adverse ecological effects include acute and chronic toxicity to susceptible aquatic organisms, with concentrations of some QACs approaching levels of concern. Suspected or known adverse health outcomes include dermal and respiratory effects, developmental and reproductive toxicity, disruption of metabolic function such as lipid homeostasis, and impairment of mitochondrial function. QACs' role in antimicrobial resistance has also been demonstrated. In the US regulatory system, how a QAC is managed depends on how it is used, for example in pesticides or personal care products. This can result in the same QACs receiving different degrees of scrutiny depending on the use and the agency regulating it. Further, the US Environmental Protection Agency's current method of grouping QACs based on structure, first proposed in 1988, is insufficient to address the wide range of QAC chemistries, potential toxicities, and exposure scenarios. Consequently, exposures to common mixtures of QACs and from multiple sources remain largely unassessed. Some restrictions on the use of QACs have been implemented in the US and elsewhere, primarily focused on personal care products. Assessing the risks posed by QACs is hampered by their vast structural diversity and a lack of quantitative data on exposure and toxicity for the majority of these compounds. This review identifies important data gaps and provides research and policy recommendations for preserving the utility of QAC chemistries while also seeking to limit adverse environmental and human health effects.

Accurate temperature measurement via magnetic resonance is valuable for both in vitro and in vivo analysis of local tissue for evaluating disease pathology and medical interventions. 1 H MRI-based thermometry is used clinically but is susceptible to error from magnetic field drift and low sensitivity in fatty tissue and requires a reference for absolute temperature determination. As an alternative, perfluorotributylamine (PFTBA), a perfluorocarbon liquid for 19 F MRI thermometry, is based on chemical shift responsiveness and approaches the sensitivity of 1 H MRI thermometry agents; however, environmental persistence, greenhouse gas concerns, and multiple resonances which can lead to MRI artifacts indicate a need for alternative sensors. Using a 19 F NMR-based structure-property study of synthetic organofluorine molecules, this research develops new organofluorine liquids with improved temperature responsiveness, high signal, and reduced nonmagnetically equivalent fluorine resonances. Environmental degradation analysis using reverse-phase HPLC and quantitative 19 F NMR demonstrates a rapid degradation profile mediated via the aryl fluorine core of temperature sensors. Our findings show that our lead liquid temperature sensor, DD-1 , can be made in high yield in a single step and possesses an improved responsiveness over our prior work and an 83% increase in aqueous thermal responsiveness over PFTBA. Degradation studies indicate robust degradation with half-lives of less than two hours under photolysis conditions for the parent compound and formation of other fluorinated products. The improved performance of DD-1 and its susceptibility to environmental degradation highlight a new lead fluorous liquid for thermometry applications.

The wavelength dependence of photoproduct formation and quantum yields was evaluated for fluorinated pesticides and pharmaceuticals using UV-light emitting diodes (LEDs) with 255, 275, 308, 365, and 405 nm peak wavelengths. The fluorinated compounds chosen were saflufenacil, penoxsulam, sulfoxaflor, fluoxetine, 4-nitro-3-trifluoromethylphenol (TFM), florasulam, voriconazole, and favipiravir, covering key fluorine motifs (benzylic-CF 3 , heteroaromatic-CF 3 , aryl-F, and heteroaromatic-F). Quantum yields for the compounds were consistently higher for UV-C as compared to UV-A wavelengths and did not show the same trend as molar absorptivity. For all compounds except favipiravir and TFM, the fastest degradation was observed using 255 or 275 nm light, despite the low power of the LEDs. Using quantitative 19 F NMR, fluoride, trifluoroacetate, and additional fluorinated byproducts were tracked and quantified. Trifluoroacetate was observed for both Ar-CF 3 and Het-CF 3 motifs and increased at longer wavelengths for Het-CF 3 . Fluoride formation from Het-CF 3 was significantly lower as compared to other motifs. Ar-F and Het-F motifs readily formed fluoride at all wavelengths. For Het-CF 3 and some Ar-CF 3 motifs, 365 nm light produced either a greater number of or different major products. Aliphatic-CF 2 /CF 3 products were stable under all wavelengths. These results assist in selecting the most efficient wavelengths for UV-LED degradation and informing future design of fluorinated compounds.

The photolysis of pesticides with different fluorine motifs was evaluated to quantify the formation of fluorinated products in buffered aqueous systems, advanced oxidation (AOP) and reduction processes (ARP), and river water. Simulated sunlight quantum yields at pH 7 were 0.0033, 0.0025, 0.0015, and 0.00012 for penoxsulam, florasulam, sulfoxaflor, and fluroxypyr, respectively. The bimolecular rate constants with hydroxyl radicals were 2 to 5.7 × 10 10 M -1 s -1 and, with sulfate radicals, 1.6 to 2.6 × 10 8 M -1 s -1 for penoxsulam, florasulam, and fluroxypyr, respectively. The rate constants of sulfoxaflor were 100-fold lower. Using quantitative 19 F-NMR, complete fluorine mass balances were obtained. The maximum fluoride formation was 53.4 and 87.4% for penoxsulam and florasulam under ARP conditions, and 6.1 and 100% for sulfoxaflor and fluroxypyr under AOP conditions. Heteroaromatic CF 3 and aliphatic CF 2 groups were retained in multiple fluorinated photoproducts. Aryl F and heteroaromatic F groups were readily defluorinated to fluoride. CF 3 and CF 2 groups formed trifluoroacetate and difluoroacetate, and yields increased under oxidizing conditions. 19 F-NMR chemical shifts and coupling analysis provided information on hydrogen loss on adjacent bonds or changes in chirality. Mass spectrometry results were consistent with the observed 19 F-NMR products. These results will assist in selecting treatment processes for specific fluorine motifs and in the design of agrochemicals to reduce byproduct formation.

Diabetes and its complications represent a real major public health problem in the world because of its high rates of morbidity and mortality. Chronic hyperglycemia, oxidative stress, dyslipidemia and inflammation play a major role in the pathophysiology of diabetes and its vascular complications. The objective of this study was to evaluate the effect of aqueous extract of S. zenkeri on chronic hyperglycemia and its complications in a streptozotocin-induced diabetic Wistar rat model. The barks of S. zenkeri were washed, dried and crushed; the powder was dissolved in distilled water (1:10 weight/volume) then macerated and the filtrate obtained was dried in an oven. Subsequently, after quantification of the bioactive compounds (total polyphenols, flavonoids and alkaloids) present in the extract, an in vivo study was conducted in an animal model of streptozotocin-induced hyperglycemia. For this fact, the rats were divided into four groups of five rats as folow: a normoglycaemia group (NC), an untreated hyperglycaemia group (PC), two hyperglycaemia groups including a test group receiving by esophageal gavage, the aqueous extract of the bark of S zenkerii (AESZ) at a dose of 300 mg/kg body weight and a control group receiving metformin at a dose of 20 mg/kg body weight. During the treatment which lasted 21 days, the weights have been taken every two days and the blood sugar levels every week. At the end of the treatment, the rats were killed under light chloroform anesthesia; the plasma, hemolysate, serum and liver homogenate prepared were used to assay the biochemical parameters of oxidative stress (catalase, MDA), lipid profile (Triglycerides, total cholesterol and HDL-cholesterol) and immunological (CRP and NFS). It emerged that the extract limited weight loss and caused a reduction in blood sugar of -26.59% after 21 days of treatment; the extract caused an increase in the activity of erythrocyte catalase and a reduction in the concentration of hepatic MDA, as well as a very marked reduction in inflammatory cells and CRP. The extract also caused a reduction in dyslipidemiawhich was materialized by a reduction in CRR, AC, AIP and an increase in CPI. These results suggest that this extract contains bioactive compounds capable of reducing chronic hyperglycemia while preventing its complications, thus justifying its traditional use in the management of diabetes., (© 2022 The Authors.)

Antimicrobials may reach the soil environment from a variety of sources and pathways, including land application of human biosolids and animal manure. Once in soil, antimicrobials can affect the abundance and activity of soil microorganisms and exert selection pressures that enhance the emergence and spread of antimicrobial resistance (AMR). To mitigate the spread of AMR it is important to understand the spatial and temporal interactions between antimicrobials and soil. The goal of this study was to assess the vulnerability of Minnesota (U.S.) soil to contamination with specific antimicrobial compounds at temperatures experienced throughout the year. Soil contamination potential was estimated based upon specific antimicrobial drug binding and permanence, and average monthly temperature. Minnesota soil vulnerability was estimated by incorporating spatially explicit soil contamination potential, land cover type, and livestock density. Assessment of antimicrobials used in livestock production showed that soils are most vulnerable to antimicrobial contamination in southwestern Minnesota, to enrofloxacin, chlortetracycline, and oxytetracycline, and in the months of April and October. While the assessment herein was not based on actual on-farm antimicrobial use data and subsequent excretion of antimicrobial metabolites into the environment, this study provides an overview of the spatial and temporal potential for Minnesota soil to be contaminated by several antimicrobial drugs and demonstrates how specific vulnerability assessments might be conducted for geographic areas with known exposure (e.g., cropland fertilized with livestock manure and/or human biosolids). Such assessments might be used to identify best practices for mitigating antimicrobial exposure to soils and guide additional research to understand the role of environmental antimicrobial contamination in the problem of AMR., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Fluorine incorporation into organic molecules has increased due to desirable changes in the molecular physiochemical properties. Common fluorine motifs include: aliphatic fluorines and -CF 3 , or -F containing groups bonded directly onto an aromatic (Ar-CF 3 and Ar-F) or heteroaromatic ring. Photolysis of these compounds, either in natural or engineered systems, is a potential source of new fluorinated byproducts. Given the potential persistence and toxicity of fluorinated byproducts, monitoring of product formation during photolysis of various fluorinated motifs is needed. 19 F-NMR is a means to detect and quantify these species. Ar-CF 3 and Ar-F model compounds (2-, 3-, and 4-(trifluoromethyl)phenol, 2-, 3-, 4-fluorophenol, and 2,6-, 3,5-difluorophenol) were photolyzed under a variety of aqueous conditions: pH 5, pH 7, pH 10, 1 mM H 2 O 2 at pH 7 to form •OH, and 0.5 mM SO 3 2- at pH 10 to form e aq - . Pharmaceuticals with the Ar-CF 3 (fluoxetine) and Ar-F plus pyrazole-CF 3 (sitagliptin) motifs were treated similarly. Parent molecule concentrations were monitored with high pressure liquid chromatography with a UV detector. Fluorine in the parent and product molecules was quantified with 19 F-NMR and complete fluorine mass balances were obtained. High resolution mass spectrometry was used to further explore product identities. The major product for Ar-F compounds was fluoride. The Ar-CF 3 model compounds led to fluoride and organofluorine products dependent on motif placement and reaction conditions. Trifluoroacetic acid was a product of 4-(trifluoromethyl)phenol and fluoxetine. Additional detected fluoxetine products identified using mass spectrometry resulted from addition of -OH to the aromatic ring, but a dealkylation product could not be distinguished from fluoxetine by 19 F-NMR. Sitagliptin formed multiple products that all retained the pyrazole-CF 3 motif while the Ar-F motif produced fluoride. 19 F-NMR, mass spectrometry, and chromatography methods provide complementary information on the formation of fluorinated molecules by modification or fragmentation of the parent structure during photolysis, allowing screening for fluorinated photoproducts and development of fluorine mass balances., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

The environment plays a key role in the spread and persistence of antimicrobial resistance (AMR). Antimicrobials and antimicrobial resistance genes (ARG) are released into the environment from sources such as wastewater treatment plants, and animal farms. This study describes an approach guided by spatial mapping to quantify and predict antimicrobials and ARG in Minnesota's waterbodies in water and sediment at two spatial scales: macro, throughout the state, and micro, in specific waterbodies. At the macroscale, the highest concentrations across all antimicrobial classes were found near populated areas. Kernel interpolation provided an approximation of antimicrobial concentrations and ARG abundance at unsampled locations. However, there was high uncertainty in these predictions, due in part to low study power and large distances between sites. At the microscale, wastewater treatment plants had an effect on ARG abundance (sul1 and sul2 in water; bla SHV , intl1, mexB, and sul2 in sediment), but not on antimicrobial concentrations. Results from sediment reflected a long-term history, while water reflected a more transient record of antimicrobials and ARG. This study highlights the value of using spatial analyses, different spatial scales, and sampling matrices, to design an environmental monitoring approach to advance our understanding of AMR persistence and dissemination., (© 2021. The Author(s).)

Background: Chronic nonsteroidal anti-inflammatory drug (NSAID) use is associated with gastrointestinal bleeding via inhibition of endogenous mucosal protection and platelet aggregation. This study aimed to determine whether extended NSAIDs after joint arthroplasty is associated with increased risk of gastrointestinal bleeding., Methods: This was a retrospective study examining 28,794 adults who underwent joint arthroplasty by one of 50 surgeons from 2016 to 2018. Episodes of gastrointestinal bleeding within 90 days postoperatively were identified prospectively. Postoperative medications were reported directly by patients with electronic questionnaires. The primary analysis was performed using binary logistic regression., Results: A total of 74 (0.26%) episodes of gastrointestinal bleeding occurred within 90 days (median 8 days) postoperatively. Of 5086 patients with complete data included in the primary analysis, 59.6% had used NSAIDs with median duration of 2 weeks (interquartile range, 0-6 weeks). Patients with gastrointestinal bleeding were significantly older (71.3 vs 67.0 years), required longer hospitalizations (2.1 vs 1.5 days), and more commonly had a history of peptic ulcers (10.8% vs 0.9%). However, there was no positive association between NSAID use and gastrointestinal bleeding. In fact, the odds of gastrointestinal bleeding were lower in patients taking NSAIDs. Gastrointestinal bleeding was associated with anticoagulants, antiplatelet agents, and, to a lesser extent, aspirin., Conclusion: NSAIDs were not associated with gastrointestinal bleeding and may be prescribed safely for a majority of patients after joint arthroplasty. The greatest odds of gastrointestinal bleeding occurred in patients with peptic ulcer disease and those who received antiplatelet and anticoagulation agents. Increasing age and bilateral surgery were also associated with gastrointestinal bleeding., Level of Evidence: Level III., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Subsurface contamination with the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) at ordnance production and testing sites is a problem because of the persistence, mobility, and toxicity of RDX and the formation of toxic products under anoxic conditions. While the utility of compound-specific isotope analysis for inferring natural attenuation pathways from stable isotope ratios has been demonstrated, the stable isotope fractionation for RDX reduction by iron-bearing minerals remains unknown. Here, we evaluated N and C isotope fractionation of RDX during reduction by Fe(II) associated with Fe minerals and natural sediments and applied N isotope ratios to the assessment of mineral-catalyzed RDX reduction in a contaminant plume and in sediment columns treated by in situ chemical reduction. Laboratory studies revealed that RDX was reduced to nitroso compounds without denitration and the concomitant ring cleavage. Fe(II)/iron oxide mineral-catalyzed reactions exhibited N isotope enrichment factors, ε N , between -6.3±0.3‰ and -8.2±0.2‰, corresponding to an apparent 15 N kinetic isotope effect of 1.04-1.05. The observed variations of the δ 15 N of ∼15‰ in RDX from groundwater samples suggested an extent of reductive transformation of 85% at an ammunition plant. Conversely, we observed masking of N isotope fractionation after RDX reduction in laboratory flow-through systems, which was presumably due to limited accessibility to reactive Fe(II).

Neonicotinoid insecticides cause adverse effects on nontarget organisms, but more information about their occurrence in surface and groundwater is needed across a range of land uses. Sixty-five sites in Minnesota, USA, representing rivers, streams, lakes, groundwater, and treated wastewater, were monitored via collection of 157 water samples to determine variability in spatiotemporal neonicotinoid concentrations. The data were used to assess relations to land use, hydrogeologic condition, and potential effects on aquatic life. Total neonicotinoid concentrations were highest in agricultural watersheds (median = 12 ng/L), followed by urban (2.9 ng/L) and undeveloped watersheds (1.9 ng/L). Clothianidin was most frequently detected in agricultural areas (detection frequency = 100%) and imidacloprid most often in urban waters (detection frequency = 97%). The seasonal trend of neonicotinoid concentrations in rivers, streams, and lakes showed that their highest concentrations coincided with spring planting and elevated streamflow. Consistently low neonicotinoid concentrations were found in shallow groundwater in agricultural regions (<1.2-16 ng/L, median = 1.4 ng/L). Treated municipal wastewater had the highest concentrations across all hydrologic compartments (12-48 ng/L, median = 19 ng/L), but neonicotinoid loads from rivers and streams (median = 4100 mg/d) were greater than in treated wastewater (700 mg/d). No samples exceeded acute aquatic-life benchmarks for individual neonicotinoids, whereas 10% of samples exceeded a chronic benchmark for neonicotinoid mixtures. Although 62% of samples contained 2 or more neonicotinoids, the observed concentrations suggest there were low acute and potential chronic risks to aquatic life. This the first study of its size in Minnesota and is critical to better understanding the drivers of wide-scale environmental contamination by neonicotinoids where urban, agricultural, and undeveloped lands are present. Environ Toxicol Chem 2021;40:1017-1033. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Atrazine, a widely used herbicide, is susceptible to photolysis. The role of triplet excited states of chromophoric dissolved organic matter ( 3 CDOM*) in the photolysis of atrazine, however, is not well understood. The direct photolysis of atrazine under irradiation sources (natural sunlight/environmentally relevant simulated solar light) and its indirect photochemical reactivity with model triplet photosensitizers (benzophenone, 2-acetonaphthone, 3'-methoxy-acetophenone, 4-carboxybenzophenone, rose bengal, methylene blue, and anthraquinone-2-sulphonate) was investigated. The reactivity of the model sensitizers and DOM (Suwannee River natural organic matter, river/lake water, and wastewater effluent), were compared. The direct photolysis quantum yield was determined as 0.0196 mol Einstein -1 in a solar simulator and 0.00437 mol Einstein -1 under natural sunlight. Considerable photosensitization was induced by triplet state (n-π*) model sensitizers, while insignificant effects on atrazine loss were discerned in natural organic matter even when oxygen, a triplet quencher, was removed. The triplet sensitizers benzophenone and 2-acetylnaphthone reacted with L-histidine and 2-propanol that were intended to quench/ scavenge 1 O 2 and hydroxyl radical • OH, respectively, and benzophenone reacted with NaN 3 as a 1 O 2 scavenger and furfuryl alcohol as a 1 O 2 trapping agent, indicating quenchers may have unanticipated effects when using model sensitizers. Atrazine loss via reaction with 3 DOM* will be relevant only in selected conditions, and this work provides a more comprehensive view on the use of model photosensitizers to mimic triplet 3 DOM*., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

To investigate possible correlates of generalised anxiety disorder (GAD) in young males with ASD, a test of the mediation effects of sensory features (SF) upon the association between ASD symptoms and GAD was conducted with 150 males aged 6 to 18 years. GAD data were obtained from parents of the boys and from the boys themselves; SF and ASD data were obtained from parents. Symptoms of ASD were found to influence elevated levels of parent-rated GAD indirectly through greater levels of sensory avoiding, and auditory-specific sensory behaviours correlated with parent-rated anxiety more strongly than other sensory modalities. There were no significant effects for the boys' self-rated GAD.

Quaternary ammonium compounds (QACs) are active ingredients in over 200 disinfectants currently recommended by the U.S. EPA for use to inactivate the SARS-CoV-2 (COVID-19) virus. The amounts of these compounds used in household, workplace, and industry settings has very likely increased, and usage will continue to be elevated given the scope of the pandemic. QACs have been previously detected in wastewater, surface waters, and sediments, and effects on antibiotic resistance have been explored. Thus, it is important to assess potential environmental and engineering impacts of elevated QAC usage, which may include disruption of wastewater treatment unit operations, proliferation of antibiotic resistance, formation of nitrosamine disinfection byproducts, and impacts on biota in surface waters. The threat caused by COVID-19 is clear, and a reasonable response is elevated use of QACs to mitigate spread of infection. Exploration of potential effects, environmental fate, and technologies to minimize environmental releases of QACs, however, is warranted., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

Quaternary ammonium compounds (QACs) are not completely removed during wastewater treatment and are frequently detected in surface waters and sediments. The photochemical transformation of QACs has not been thoroughly investigated as a potential degradation pathway affecting their fate in the environment. Kinetic studies of common QACs with and without aromatic groups under simulated and natural sunlight conditions were performed with model sensitizers and dissolved organic matter to estimate photochemical half-lives in the aquatic environment. All QACs investigated react with hydroxyl radicals at diffusion-controlled rates (∼2.9 × 109 to 1.2 × 1010 M-1 s-1). Benzethonium reacted via direct photolysis (ΦBZT,outdoor = 1.7 × 10-2 (mol Ei-1)). Benzethonium also reacted with the triplet excited state model sensitizer 2-acetylnaphthalene, but evidence suggests this reaction pathway is unimportant in natural waters due to faster quenching of the triplet 2-acetylnapthalene by oxygen. Reactivity with singlet oxygen for the QACs was minimal. Overall, reactions with hydroxyl radicals will dominate over direct photolysis due to limited spectral overlap of sunlight emission and QAC absorbance. Photolysis half-lives are predicted to be 12 to 94 days, indicating slow abiotic degradation in surface water.

Absorption of solar radiation by colored dissolved organic matter (CDOM) in surface waters results in the formation of photochemically produced reactive intermediates (PPRIs) that react with pollutants in water. Knowing the steady-state concentrations of PPRIs ([PPRI] ss ) is critical to predicting the persistence of pollutants in sunlit surface waters. CDOM levels ( a 440 ) can be measured remotely for lakes over large areas using satellite imagery. Laboratory measurements of [PPRI] ss and apparent quantum yields (Φ) of three PPRIs ( 3 DOM*, 1 O 2 , and • OH) were made for 24 lake samples under simulated sunlight. The total rate of light absorption by the water samples ( R a ), the rates of formation ( R f ), and [PPRI] ss of 3 DOM* and 1 O 2 linearly increased with incre a sing a 440 . The production rate of • OH was linearly correlated with a 440 , but the steady-state concentration was best fit by a logarithmic function. The relationship between measured a 440 and Landsat 8 reflectance was used to map a 440 for more than 10 000 lakes across Minnesota. Relationships of a 440 with R f , [PPRIs] ss , and R a were coupled with satellite-based a 440 assessments to map reactive species production rates and concentrations as well as contaminant transformation rates. This study demonstrates the potential for using satellite imagery for estimating contaminant loss via indirect photolysis in lakes.

Remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS) is particularly challenging due to the resistance of the molecule to oxidation because of the strength of the carbon-fluorine bond and the need to achieve low nanogram per liter drinking water targets. Previous studies have shown that activated carbon is an effective sorbent for removal of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in conventional water treatment systems. The objective of this study was to evaluate the in situ delivery and sorptive capacity of an aqueous suspension containing powdered activated carbon (PAC) stabilized with polydiallyldimethylammonium chloride (polyDADMAC). Batch reactor studies demonstrated substantial adsorption of PFOA and PFOS by polyDADMAC-stabilized PAC, which yielded Freundlich adsorption coefficients of 156 and 629 L/g - n , respectively. In columns packed with 40-50 mesh Ottawa sand, injection of a PAC (1000 mg/L) + polyDADMAC (5000 mg/L) suspension created a sorptive region that increased subsequent PFOA and PFOS retention by 3 orders of magnitude relative to untreated control columns, consistent with the mass of retained PAC. Experiments conducted in a heterogeneous aquifer cell further demonstrated the potential for stabilized-PAC to be an effective in situ treatment option for PFAS-impacted groundwater.

Ferrous iron-bearing minerals are important reductants in the contaminated subsurface, but their availability for the reduction of anthropogenic pollutants is often limited by competition with other electron acceptors including microorganisms and poor accessibility to Fe(II) in complex hydrogeologic settings. The supply of external electron donors through in situ chemical reduction (ISCR) has been proposed as one remediation approach, but the quantification of pollutant transformation is complicated by the perturbations introduced to the subsurface by ISCR. Here, we evaluate the application of compound specific isotope analysis (CSIA) for monitoring the reduction of 2,4-dinitroanisole (DNAN), a component of insensitive munitions formulations, by mineral-bound Fe(II) generated through ISCR of subsurface material from two field sites. Electron balances from laboratory experiments in batch and column reactors showed that 3.6% to 11% of the total Fe in the sediments was available for the reduction of DNAN and its partially reduced intermediates after dithionite treatment. The extent of DNAN reduction was successfully quantified from its N isotope fractionation measured in the column effluent based on the derivation of a N isotope enrichment factor, ε N , derived from a comprehensive series of isotope fractionation experiments with numerous Fe(II)-bearing minerals as well as dithionite-reduced subsurface materials. Our observations illustrate the utility of CSIA as a robust approach to evaluate the success of in situ remediation through abiotic contaminant reduction.

Quaternary ammonium compounds (QACs) are widely applied as surfactants and biocides in cleaning and personal-care products. Because of incomplete removal during wastewater treatment, QACs are present in wastewater effluents, with which they are discharged into natural waters, where they accumulate in sediments. To assess the levels of QACs in aquatic environments, a liquid chromatography high-resolution mass spectrometry method using both target and suspect screening was developed. The water and sediment sample preparation, measurement, and data analysis workflow were optimized for 22 target compounds with a wide range of hydrophobicity, including ionic liquids that have potential use as solvents and QACs common in personal-care and sanitizing products. In wastewater effluents, average concentrations of all target and suspect QACs combined ranged from 0.4 μg L-1 to 6.6 μg L-1. Various homologs of benzylalkyldimethylammonium (BAC) and dialkyldimethylammonium (DADMAC) as well as the ionic liquid butylpyridinium and 15 suspect QACs were detected in at least one wastewater effluent sample. A spatial profile of sediment samples in a lake demonstrated potential inputs from both municipal wastewater effluent and agricultural sources for BACs. In sediment cores, two distinct trends of temporal QAC accumulation were observed. In lakes with large watersheds and mixed domestic and industrial wastewater sources (Lake Pepin and Duluth Harbor), peak concentrations of QACs were found at depths corresponding to deposition in the 1980s and decreases after this time are attributed to improved wastewater treatment and source control. In a smaller lake with predominantly domestic wastewater inputs (Lake Winona), concentrations of QACs increased slowly over time until today.

Wastewater treatment using encapsulated biomass is a promising approach for high-rate resource recovery. Encapsulation matrices can be customized to achieve desired biomass retention and mass transport performance. This, in turn, facilitates treatment of different waste streams. In this study, a model was developed to describe calcium-alginate beads encapsulating hydrogen-producing biomass, with the goal of enabling appropriate a priori customization of the system. The model was based on a classic diffusion-reaction model, but also included the growth of encapsulated biomass and product inhibition. Experimental data were used to verify the model, which accurately described the effect of hydraulic retention time, bead size, and feed concentration on resource (hydrogen) recovery from brewery wastewater. Sensitivity analyses revealed that the hydrogen production rate was insensitive to substrate diffusivity and bead size, but sensitive to the substrate partition coefficient, initial encapsulated biomass concentration, and the total volume of beads in the reactor, demonstrating that this system was growth-limited rather than diffusion-limited under the tested conditions. Because the model quantifies the relationship between the hydrogen production rate and various input and operating parameters, it should be possible to extend the model to determine the most cost-effective system for optimal performance with a given waste stream., (© 2019 Wiley Periodicals, Inc.)

The ability of satellites to assess surface water quality indicators such as colored dissolved organic matter (CDOM) suggests that remote sensing could be a useful tool for evaluating water treatability metrics in considering potential drinking water supplies. To explore this possibility, 24 surface water samples were collected throughout Minnesota, USA with wide ranging values of CDOM (a 440 ; 0.41-27.9 m -1 ), dissolved organic carbon (DOC; 5.5-47.6 mg/L) and specific ultraviolet absorbance at 254 nm (SUVA 254 ; 1.3-5.1 L/mg-M). Laboratory experiments were performed to quantify chlorine demand and the formation of two classes of halogenated disinfection byproducts (DBPs), trihalomethanes (THMs) and haloacetic acids (HAAs), using the uniform formation conditions (UFC) test. Chlorine demand and THM UFC were linearly correlated with CDOM (R 2  = 0.97 and 0.91, respectively), indicating that CDOM is a useful predictor of these parameters. On the other hand, data comparing di- and tri-HAA UFC with CDOM were better fit by a logarithmic relationship (R 2  = 0.73 and 0.87, respectively), while mono-HAA UFC was linearly correlated with CDOM (R 2  = 0.46) but only for low-to moderately-colored waters (a 440  ≤ 11 m -1 ). The correlations relating chlorine demand and DBP UFC values with CDOM were coupled with satellite CDOM assessments to estimate chlorine demand and DBP UFC values for all surface waters larger than 0.05 km 2 in the state of Minnesota, USA. The resulting maps suggest that only 21.8% of Minnesota lakes would meet both the THM and HAA maximum contaminant levels, but only when pre-disinfection treatment removes 75% of DBP precursors. There are limitations to determining CDOM using satellites for high color surface waters (a 440  > 11 m -1 ), however, leading to underpredicted values for CDOM, chlorine demand, and DBP UFC . Overall, the results demonstrate the potential benefits of satellite remote sensing for assessing potential drinking water sources and water treatability metrics., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The organic matter present in wastewater effluents (EfOM), is likely to have different properties than the organic matter present in the receiving water. The properties of EfOM will affect the fate of contaminants of emerging concern because EfOM is a source of photochemically produced reactive intermediates (PPRIs) capable of transforming contaminants. Effluent water samples were taken seasonally from sixteen wastewater treatment plants in Minnesota and two effluent dominated rivers in California and Arizona. Samples (n = 94) were tested for water chemistry, light absorption characteristics, and excited state triplet organic matter ( 3 EfOM ∗ ) and singlet oxygen ( 1 O 2 ) production. Based on analysis of spectral parameters, EfOM had higher molecular weight and lower aromatic content than organic matter present in stormwaters from Minnesota, which are representative of human-impacted natural organic matter (NOM) containing waters. The second order rate constant for the reaction of the 3 EfOM ∗ probe 2,4,6-trimethylephenol (k T,TMP ) for the effluents was 7.79 (±3.03) × 10 8  M -1 s -1 , and this value was used to calculate apparent quantum yields for 3 EfOM ∗ production, which ranged from 0.006 to 0.114. The quantum yield for the production of singlet oxygen ranged from 0.007 to 0.064. Processes in the wastewater treatment train, season, and water chemistry parameters did not serve as predictors of 3 EfOM ∗ or 1 O 2 production. Among the parameters measured, Spearman rank correlations were strongest between quantum yields of 1 O 2 and 3 EfOM ∗ and E2/E3 (absorption at 250 nm/absorption at 365 nm). This relationship, however, is weaker than that previously observed for NOM. The efficiency of 1 O 2 production from 3 EfOM ∗ was 54%. Results indicate that 2,4,6-trimethylphenol samples nearly all of the triplets in EfOM that have sufficient energy to produce 1 O 2 , which may not be the case for NOM., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Secchi depth (SD), a primary metric to assess trophic state, is controlled in many lakes by algal densities, measured as chlorophyll-a (chl-a) concentration. Two other optically related water quality variables also directly affect SD: non-algal suspended solids (SS NA ) and colored dissolved organic matter (CDOM, expressed as the absorption coefficient at 440 nm, a 440 ). Using a database of ~1,460 samples from ~625 inland lake basins in Minnesota and two other Upper Midwest states, Wisconsin and Michigan, we analyzed relationships among these variables, with special focus on CDOM levels that influence SD values and the Minnesota SD standards used to assess eutrophication impairment of lakes. Log-transformed chl-a, total suspended solids (TSS), and SD were strongly correlated with each other; log(a 440 ) had major effects on log(SD) but was only weakly correlated with log(chl-a) and log(TSS). Multiple regression models for log(SD) and 1/SD based on the three driving variables (chl-a, SS NA , and CDOM) explained ~80% of the variance in SD in the whole data set, but substantial differences in the form of the best-fit relationships were found between major ecoregions. High chl-a concentrations (> 50 μg/L) and TSS (> 20 mg/L) rarely occurred in lakes with high CDOM (a 440  > ~4 m -1 ), and all lakes with a 440  > 8 m -1 had SD ≤ 2.0 m despite low chl-a values (<10 μg/L) in most lakes. Further statistical analyses revealed that CDOM has significant effects on SD at a 440 values > ~ 4 m -1 . Thus, SD is not an accurate trophic state metric in moderately to highly colored lakes, and Minnesota's 2-m SD criterion should not be the sole metric to assess eutrophication impairment in warm/cool-water lakes of the Northern Lakes and Forest ecoregion. More generally, trophic state assessments using SD in regions with large landscape sources of CDOM need to account for effects of CDOM on SD., (© 2019 by the Ecological Society of America.)

Colored dissolved organic matter (CDOM), a major component of the dissolved organic carbon (DOC) pool in many lakes, is an important controlling factor in lake ecosystem functioning. Absorption coefficients at 440 nm (a440, m-1), a common measure of CDOM, exhibited strong associations with dissolved iron (Fediss) and DOC in 280 lakes of the Upper Great Lakes States (UGLS: Minnesota, Wisconsin, and Michigan), as has been found in Scandinavia and elsewhere. Linear regressions between the three variables on UGLS lake data typically yielded R2 values of 0.6-0.9, suggesting that some underlying common processes influence organic matter and Fediss. Statistical and experimental evidence, however, supports only a minor role for iron contributions to a440 in UGLS lakes. Although both DOC and Fediss were significant variables in linear and log-log regressions on a440, DOC was the stronger predictor; adding Fediss to the linear a440-DOC model improved the R2 only from 0.90 to 0.93. Furthermore, experimental additions of FeIII to colored lake waters had only small effects on a440 (average increase of 0.242 m-1 per 100 μg/L of added FeIII). For 136 visibly stained waters (with a440 > 3.0 m-1), where allochthonous DOM predominates, DOM accounted for 92.3 ± 5.0% of the measured a440 values, and Fediss accounted for the remainder. In 75% of the lakes, Fediss accounted for < 10% of a440, but contributions of 15-30% were observed for 7 river-influenced lakes. Contributions of Fediss in UGLS lakes to specific UV absorbance at 254 nm (SUVA254) generally were also low. Although Fediss accounted for 5-10% of measured SUVA254 in a few samples, on average, 98.1% of the SUVA254 signal was attributable to DOM and only 1.9% to Fediss. DOC predictions from measured a440 were nearly identical to those from a440 corrected to remove Fediss contributions. Overall, variations in Fediss in most UGLS lakes have very small effects on CDOM optical properties, such as a440 and SUVA254, and negligible effects on the accuracy of DOC estimated from a440, data for which can be obtained at broad regional scales by remote sensing methods., Competing Interests: The authors have declared that no competing interests exist.

The recent development of insensitive munitions, such as 2,4-dinitroanisole (DNAN), as components of military explosives has generated concern for potential subsurface contamination and created a need to fully characterize their transformation processes. Compound specific isotope analysis (CSIA) has proven to be a useful means of assessing transformation pathways according to characteristic stable isotope fractionation patterns. The C and N isotope fractionation of DNAN associated with abiotic and enzymatic hydrolysis was recently assessed. The extent to which DNAN isotope fractionation will be affected by other potentially competing transformation pathways known for nitroaromatic compounds (e.g., reduction) and if previous knowledge can be extrapolated to other environmental matrices remains to be understood. Here, we investigated the C and N isotope fractionation and reaction rate constants of DNAN during abiotic reduction mediated by mineral-associated Fe(ii) species as a function of mineral type, natural organic matter presence, and repeated exposures to DNAN. Though rate constants varied, N and C apparent kinetic isotope effects (AKIEs) remained consistent across all experiments (averaged values of 15N-AKIE = 1.0317 ± 0.0064 and 13C-AKIE = 1.0008 ± 0.0005) and revealed significant 15N- and minimal 13C-enrichment in agreement with previous work on nitroaromatic compounds. Moreover, the observed fractionation was clearly distinct from trends for abiotic and enzymatic hydrolysis. This study provides a strengthened basis for the use of CSIA as a robust tool for monitoring DNAN degradation in complex environmental matrices as a component of future remediation efforts.

The removal and fate of contaminants of emerging concern (CECs) in water treatment systems is of interest given the widespread occurrence of CECs in water supplies and increase in direct potable reuse of wastewater. In this study, CEC removal was investigated in pilot-scale biologically-active granular activated carbon (GAC)-sand and anthracite-sand filters under different hydraulic loading rates and influent CEC concentrations over a 15-month period. Eight of the most commonly detected compounds in a survey of CEC occurrence in drinking water were selected for this study: atenolol, atrazine, carbamazepine, fluoxetine, gemfibrozil, metolachlor, sulfamethoxazole and tris(2-chloroethyl) phosphate (TCEP). GAC-sand biofilters provided superior CEC removal for all compounds (mean removal efficiencies: 49.1-94.4%) compared to anthracite-sand biofilters (mean removal efficiencies: 0-66.1%) due to a combination of adsorption and biodegradation. Adsorption was determined to be the dominant removal mechanism for most selected CECs, except fluoxetine, which had the greatest biodegradation rate constant (0.93 ± 0.15 min -1  at 20-28 °C). The mean removal efficiency decreased by 16.5% when the loading rate increased from 2 to 4 gpm/ft 2 (4.88-9.76 m/h). A significant reduction in CEC removal was observed after 100,000 bed volumes when the influent CEC concentration was low (100-200 ng/L), whereas no significant reduction was observed during spike dosing (1000-3000 ng/L). A regression analysis suggested that biodegradation rate, hydraulic loading rate, influent CEC concentration, throughput, influent dissolved organic carbon (DOC) concentration, and CEC charge are important parameters for predicting CEC removal performance in GAC-sand biofilters., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is known to undergo reduction mediated by ferrous iron in the presence of minerals, including magnetite. Idealized laboratory conditions may not provide representative reaction kinetics or pathways compared to field conditions. The effects of magnetite mineral morphology, the aquifer material matrix, the presence of aqueous Fe(II), and the buffer identity on RDX reduction kinetics and intermediate formation are investigated in this work. Reactions in bicarbonate buffer were substantially slower than those performed in 3-(N-morpholino)propanesulfonic acid (MOPS) buffer, and the presence of quartz and clays in magnetite-containing aquifer material resulted in slower reaction kinetics and production of additional iron oxide phases. Buffer identity also changed the rate controlling step and reaction product distribution. Conditions as close to those expected in field systems are necessary to evaluate the reaction rates and pathways of RDX in reduced groundwater systems., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Neonicotinoid insecticides are the most widely used class of insecticides worldwide. Concern has grown over their widespread environmental presence and potential unintended adverse effects. The present study examined hydrolysis and photolysis reaction rates of neonicotinoids and assessed any residual toxicity of reaction products. Hydrolysis rates were tested between pH 4 and 10 and found to be base-catalyzed. Experiments revealed a nonelementary rate law for hydrolysis, with the hydroxide concentration raised to a power of 0.55 ± 0.09, which has implications for accurate prediction of environmental half-lives. Divalent metal ions (Cu 2+ , Ni 2+ , Zn 2+ ) and minerals (kaolinite, goethite, TiO 2 ) had no effect on hydrolysis rates. The hydrolysis rate in a natural water, however, was slower than that predicted by buffered experiments. Nitenpyram, imidacloprid, thiamethoxam, and clothianidin reacted via direct photolysis in both ultrapure and natural waters, with average quantum yields of 0.024 ± 0.001, 0.0105 ± 0.0002, 0.0140 ± 0.0002, and 0.0101 ± 0.0001, respectively. Acetamiprid primarily underwent indirect photolysis by reaction with OH· (1.7 ± [0.2] × 10 9  M -1  s -1 ). For all compounds, the urea derivative was the most commonly detected product in both hydrolysis and photolysis experiments. Using mosquito (Culex pipiens) larvae, no residual toxicity of reaction products was observed. Results indicate long environmental half-lives for the tested neonicotinoids, which may help to explain their ubiquitous presence in environmental matrices. Environ Toxicol Chem 2018;37:2797-2809. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC., (© 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc.)

Triplet-state chromophoric dissolved organic matter ( 3 CDOM*) plays an important role in aquatic photochemistry, yet much remains unknown about the reactivity of these intermediates. To better understand the kinetic behavior and reactivity of 3 CDOM*, we have developed an indirect observation method based on monitoring time-resolved singlet oxygen ( 1 O 2 ) phosphorescence kinetics. The underpinning principle of our approach relies on the fact that O 2 quenches almost all triplets with near diffusion limited rate constants, resulting in the formation of 1 O 2 , which is kinetically linked to the precursors. A kinetic model relating 1 O 2 phosphorescence kinetics to triplet excited states produced from isolated humic substances and in whole natural-water samples (hereafter referred to as 3 CDOM*) was developed and used to determine rate constants governing 3 CDOM* natural lifetimes and quenching by oxygen and 2,4,6-trimethylphenol (TMP), a common triplet probe molecule. 3 CDOM* was found to exhibit smaller O 2 and TMP quenching rate constants, ∼9 × 10 8 and ∼8 × 10 8 M -1 s -1 , respectively, compared with model sensitizers, such as aromatic ketones. Findings from this report shed light on the fundamental photochemical properties of CDOM in organic matter isolates and whole waters and will help refine photochemical models to more accurately predict pollutant fate in the environment.

Antibiotic chemicals and antibiotic resistance genes enter the environment via wastewater effluents as well as from runoff from agricultural operations. The relative importance of these two sources, however, is largely unknown. The relationship between the concentrations of chemicals and genes requires exploration, for antibiotics in the environment may lead to development or retention of resistance genes by bacteria. The genes that confer resistance to metal toxicity may also be important in antibiotic resistance. In this work, concentrations of 19 antibiotics (using liquid chromatography tandem mass spectrometry), 14 metals (using inductively coupled plasma-mass spectrometry), and 45 metal, antibiotic, and antibiotic-resistance associated genes (using a multiplex, microfluidic quantitative polymerase chain reaction method) were measured in 13 sediment samples from two large rivers as well as along a spatial transect in a wastewater effluent-impacted lake. Nine of the antibiotics were detected in the rivers and 13 were detected in the lake. Sixteen different resistance genes were detected. The surrounding land use and proximity to wastewater treatment plants are important factors in the number and concentrations of antibiotics detected. Correlations among antibiotic chemical concentrations, metal concentrations, and resistance genes occur over short spatial scales in a lake but not over longer distances in major rivers. The observed correlations likely result from the chemicals and resistance genes arising from the same source, and differences in fate and transport over larger scales lead to loss of this relationship.

The widespread detection of antibiotics in the environment is concerning because antibiotics are designed to be effective at small doses. The objective of this work was to quantify the accumulation rates of antibiotics used by humans and animals, spanning several major antibiotic classes (sulfonamides, tetracyclines, fluoroquinolones, and macrolides), in Minnesota lake-sediment cores. Our goal was to determine temporal trends, the major anthropogenic source to these lacustrine systems, and the importance of natural production. A historical record of usage trends for ten human and/or animal-use antibiotics (four sulfonamides, three fluoroquinolones, one macrolide, trimethoprim, and lincomycin) was faithfully captured in the sediment cores. Nine other antibiotics were not detected. Ofloxacin, trimethoprim, sulfapyridine, and sulfamethazine were detected in all of the anthropogenically-impacted studied lakes. Maximum sediment fluxes reached 20.5ngcm -2 yr -1 (concentration 66.1ng/g) for ofloxacin, 1.2ngcm -2 yr -1 (1.2ng/g) for trimethoprim, 3.3ngcm -2 yr -1 (11.3ng/g) for sulfapyridine, and 1.0ngcm -2 yr -1 (1.6ng/g) for sulfamethazine, respectively. Natural production of lincomycin may have occurred in one lake at fluxes ranging from 0.4 to 1.8ngcm -2 yr -1 (0.1 to 5.8ng/g). Wastewater effluent appears to be the primary source of antibiotics in the studied lakes, with lesser inputs from agricultural activities., (Copyright © 2017 Elsevier B.V. All rights reserved.)