Herbicides In River Water Research Articles

Carbon black nanoparticles to sense algae oxygen evolution for herbicides detection: Atrazine as a case study

A novel amperometric algae-based biosensor was developed for the detection of photosynthetic herbicides in river water. The green photosynthetic algae Chlamydomonas reinhardtii was immobilized on carbon black modified screen-printed electrodes, exploiting carbon black as smart nanomaterial to monitor changes in algae oxygen evolution during the photosynthetic process. The decrease of oxygen evolution, occurring in the presence of herbicides, results in a decrease of current signals by means of amperometric measurements, in an analyte concentration dependent manner. Atrazine as case study herbicide was detected in a concentration range of 0.1 and 50 μM, with a linear range from 0.1 to 5 μM and a detection limit of 1 nM. No interference was observed in presence of 100 ppb arsenic, 20 ppb copper, 5 ppb cadmium, 10 ppb lead, 10 ppb bisphenol A, and 1 ppb paraoxon, tested as safety limits. A ~25% matrix effect and satisfactory recovery values of 107 ± 10% and 96 ± 8% were obtained in river water for 3 and 5 μM of atrazine, respectively. Stability studies were also performed obtaining a high working stability up to 10 h and repeatability with an RSD of 1.1% (n = 12), as well as a good storage stability up to 3 weeks.

Solid-phase extraction of estrogens and herbicides from environmental waters for bioassay analysis-effects of sample volume on recoveries.

Ecotoxicological screening of surface waters can involve multiple analyses using multiple bioassay and chemical analytical methods that require enriched samples to reach low concentrations. Such broad screening of the same sample necessitates sufficient sample volume-typically several liters-to produce a sufficient amount of enriched sample. Often, this is achieved by performing parallel solid-phase extractions (SPE) where extracts are combined into a pool-this is a laborious process. In this study, we first validated our existing SPE method for the chemical recovery of an extended set of compounds. We spiked four estrogenic compounds and 11 herbicides to samples from independent rivers (1L) and wastewater treatment plant effluents (0.5L). Then, we investigated the effect of increased sample loading of the SPE cartridges on both chemical and biological recoveries by comparing the validated volumes with four times larger sample volumes (i.e., 4 L river water and 2 L effluent). Samples were analyzed by LC-MS/MS and three bioassays: an estrogen receptor transactivation assay (ERα-CALUX), the combined algae test, and a bacterial bioluminescence inhibition assay. Our existing SPE method was found to be suitable for enriching the extended set of estrogens and herbicides in river water and effluents with near to perfect chemical recoveries (~ 100%), except for the herbicide metribuzin (46 ± 19%). In the large volume river and effluent samples, the biological activities and concentrations of the spiked compounds were between 87 and 104% of those measured with the lower sample loading, which is adequate. In addition, the ratio between the large and original volume SPE method for the non-target endpoint (bacterial bioluminescence inhibition) was acceptable (on average 82 ± 9%). Results indicate that our current water extraction method can be applied to up to four times larger sample volumes, resulting in four times more extract volumes, without significant reductions in recoveries for the tested estrogens and herbicides. Graphical abstract ᅟ.

Solar photolytic ozonation for the removal of recalcitrant herbicides in river water

Photolytic ozonation of a river water has been performed by means of simulated solar radiation. The application of solar radiation, limiting the complete radiation spectrum (300–800 nm) to 320–800 nm and 390–800 nm, during the aqueous ozone decomposition has been assessed. A kinetic mechanism, including the influence of initiation, promotion and scavenging substances has been proposed, successfully modeling the experimental data. Radiation improves O3 decomposition rate, as a promoter, being higher if the complete UV–visible spectrum is applied. Also, pH positively influences O3 decomposition rate from pH = 4 to 8.Photolytic ozonation has been also proved to be effective in the removal of a mixture of three pyridine herbicides, dissolved in the river matrix. Radiation filters (320 nm and 390 nm cut-off) and pH have been selected as the main variables of the study. The enhanced oxidation rate registered when applying solar radiation and O3 relays on the higher formation of hydroxyl radicals, responsible for the oxidation of these recalcitrant-to-ozone herbicides. Moreover, the estimated RCT ratios confirmed the minimal differences of applying radiation or not at increasing pH, what is due to the ability of hydroxide anion to catalyze the decomposition of O3 into HO. The mineralization of the photolytic ozonation process (300–800 nm) reached 60%, whatever the pH considered. The increase of pH minimizes the differences in mineralization between the two technologies, the single ozonation achieving 50% at alkaline pH.

Herbicides in river water across the northeastern Italy: occurrence and spatial patterns of glyphosate, aminomethylphosphonic acid, and glufosinate ammonium.

Glyphosate and glufosinate ammonium are the active ingredients of commonly used herbicides. Active agricultural lands extend over a large part of the Veneto region (Eastern Po Valley, Italy) and glyphosate and glufosinate ammonium are widely used. Consequently, surface waters can be potentially contaminated. This study investigates the occurrence of glyphosate and glufosinate ammonium as well as aminomethylphosphonic acid (AMPA, the degradation product of glyphosate) in river water of Veneto. Eighty-six samples were collected in 2015 at multiple sampling points across the region. Samples were analyzed for the two target herbicides, AMPA as well as for other variables, including water temperature, pH, dissolved oxygen, conductivity, hardness, BOD, COD, inorganic ions, total nitrogen, total phosphorus, total suspended solids, arsenic, and lead. The average concentrations (all samples) were 0.17, 0.18, and 0.10μgL-1 for glyphosate, AMPA, and glufosinate ammonium, respectively. The European upper tolerable level for pesticides (annual average 0.1μgL-1) was often exceeded. Chemometric analysis was therefore applied to (i) investigate the relationships among water pollutants, (ii) detect the potential sources of water contamination, (iii) assess the effective water pollution of rivers by identifying river basins with anomalous pollution levels, and (iv) assess the spatial variability of detected sources. Factor analysis identified four factors interpreted as potential sources and processes (use of herbicides, leaching of fertilizers, urban/industrial discharges, and the biological activity on polluted or stagnant waters). A discriminant analysis revealed that the pollution from anthropogenic discharges is homogeneously present in surface water of Veneto, while biological activity and fertilizers present heterogeneous distributions. This study gives insights into the concentrations of herbicides in rivers flowing through a wide region that has heavy use of these chemicals in agriculture. The study also points out some hot-spots and suggests the future implementation of the current monitoring protocols and network.

A host–guest complexation based fluorescent probe for the detection of paraquat and diquat herbicides in aqueous solutions

A new method based on fluorescence quenching of host–guest complexation was proposed for the determination of the two herbicides in river water and cabbages. The method is rapid, direct and simple.

Simultaneous Determination of Traces of Herbicides in River Water

Simultaneous Determination of Traces of Herbicides in River Water

Molecularly imprinted polymers for triazine herbicides prepared by multi-step swelling and polymerization method: Their application to the determination of methylthiotriazine herbicides in river water

Uniformly-sized, molecularly imprinted polymers (MIPs) for atrazine, ametryn and irgarol were prepared by a multi-step swelling and polymerization method using ethylene glycol dimethacrylate as a cross-linker and methacrylic acid (MAA), 2-(trifluoromethyl) acrylic acid (TFMAA) or 4-vinylpyridine either as a functional monomer or not. The MIP for atrazine prepared using MAA showed good molecular recognition abilities for chlorotriazine herbicides, while the MIPs for ametryn and irgarol prepared using TFMAA showed excellent molecular recognition abilities for methylthiotriazine herbicides. A restricted access media-molecularly imprinted polymer (RAM-MIP) for irgarol was prepared followed by in situ hydrophilic surface modification using glycerol dimethacrylate and glycerol monomethacrylate as hydrophilic monomers. The RAM-MIP was applied to selective pretreatment and enrichment of methylthiotriazine herbicides, simetryn, ametryn and prometryn, in river water, followed by their separation and UV detection via column-switching HPLC. The calibration graphs of these compounds showed good linearity in the range of 50–500 pg/mL ( r > 0.999) with a 100 mL loading of a river water sample. The quantitation limits of simetryn, ametryn and prometryn were 50 pg/mL, and the detection limits were 25 pg/mL. The recoveries of simetryn, ametryn and prometryn at 50 pg/mL were 101%, 95.6% and 95.1%, respectively. This method was successfully applied for the simultaneous determination of simetryn, ametryn and prometryn in river water.

Simultaneous determination of phenyl- and sulfonyl-urea herbicides in river water at sub-parts-per-billion level by on-line preconcentration and liquid chromatography–tandem mass spectrometry

A method based on on-line preconcentration followed by liquid chromatography-electrospray ionization–tandem mass spectrometry (LC-ESI–MS/MS) was developed for the determination of three sulfonyl-urea (thifensulfuron, metsulfuron, chlorsulfuron) and two phenyl-urea (isoproturon and chlortoluron) herbicides in water at sub-ppb concentration ranges. Preconcentration was accomplished using on-line enrichment on a C18 cartridge; the procedure was optimized by an evaluation of the breakthrough volumes for the target analytes. Subsequently, LC-ESI–MS/MS was adopted for analytes separation and detection. In particular, a selective reaction monitoring (SRM) approach, based on the detection of a peculiar fragment for each analyte, was chosen for MS/MS analysis, in order to enhance selectivity. Normalization to the response of a phenyl-urea herbicide (chloroxuron), used as an internal standard, was also adopted to achieve a reproducibility enhancement. The described method was applied to the analysis of the target analytes in river water samples and LOD values ranging between 8 and 30 ppt were obtained.

Effect of uncertainties in agricultural working schedules and Monte-Carlo evaluation of the model input in basin-scale runoff model analysis of herbicides

In the prediction of time-series concentrations of herbicides in river water with diffuse-pollution hydrological models, farming schedules (the dates of herbicide application and drainage of irrigation water from rice paddies) greatly affect the runoff behavior of the herbicides. For large catchments, obtaining precise data on farming schedules is impractical, and so the model input inevitably includes substantial uncertainty. This paper evaluates the effectiveness of using the Monte-Carlo method to generate sets of estimated farming schedules to use as input to a GIS-based basin-scale runoff model to predict the concentrations of paddy-farming herbicides in river water. The effects of using the Monte-Carlo method to compensate for uncertainty in the evaluated parameters for herbicide decomposition and sorption were also evaluated.

A multi-biosensor based on immobilized Photosystem II on screen-printed electrodes for the detection of herbicides in river water

A multi-biosensor for detection of herbicides and pollutants was constructed using various photosynthetic preparations as biosensing elements. The photosynthetic thylakoid from Spinacia oleracea L., Senecio vulgaris and its mutant resistant to atrazine were immobilized with (BSA-GA) on the surface of screen-printed sensors composed of a graphite-working electrode and Ag/AgCl reference electrode deposited on a polymeric substrate. The biosensor was composed of four flow cells with independent illumination of 650 nm to activate electron transfer in Photosystem II. The principle of the detection was based on the fact that herbicides selectively block electron transport activity in a concentration-dependent manner and that the four PSII biomediators show differential recognition activity toward herbicides. Changes of the activity were registered amperometrically as rate of photoreduction of the artificial electron acceptor DQ. The setup resulted in a reusable herbicide multibiosensor with a good stability (half-life of 16.7 h for spinach thylakoids) and limit of detection of about 10(-8) M for herbicides recovered in spring in river.

Persistence of four s-triazine herbicides in river, sea and groundwater samples exposed to sunlight and darkness under laboratory conditions

The persistence of terbuthylazine, simazine, atrazine and prometryn ( s-triazine herbicides) was studied in sea, river and groundwaters during long-term laboratory incubation (127 days) under different laboratory conditions (light–darkness at 20 °C). Analysis of herbicides was performed by GC-NPD and their identity was confirmed by GC-MSD. A micro on-line method for the isolation of herbicide residues was used. The results showed that light had little effect on the removal of the four herbicides in riverwater but had a marked effect on their removal from sea and groundwater. Surprisingly, this removal appeared to be inversely proportional to the concentration of dissolved organic materials. In general, the degradation order was similar in sea and riverwaters; simazine was the most readily degraded compound ( t 1/2=29–49 days), while terbuthylazine was the most persistent with the longest half-lives (76–331 days). In groundwater, terbuthylazine also showed greater persistence but prometryn was the compound with a fastest degradation rate, half-lives ranged from 88 days for prometryn to approximately 100 days for the other three compounds in light conditions and 263–366 days for prometryn and terbuthylazine, respectively, in darkness. Only for terbuthylazine was the remaining percentage at the end of the experiment higher than 50% under light conditions in riverwater, while in the other cases, the remaining percentage varied from 7 to 43% for simazine in seawater and atrazine in groundwater, respectively. Finally, a greater persistence was observed in groundwater for the four compounds.

Monitoring of phenylurea and propanil herbicides in river water by solid-phase-extraction high performance liquid chromatography with photoinduced-fluorimetric detection

The separation and determination of five herbicides, including propanil and the phenylureas diuron, isoproturon, linuron and neburon, has been performed by an HPLC method, using photochemically-induced fluorescence detection. The non-fluorescent herbicides were transformed into fluorescent compounds by post-column photochemical reaction. A 60:40 (v/v) acetonitrile–buffer solution of potassium phosphate dibasic (pH 7, 0.01 M) was used for the chromatographic elution to separate propanil, linuron and neburon. The overlapping of isoproturon and diuron peaks, in the selected conditions, was resolved by changing the initial movil phase composition to 50:50 (v/v) methanol–buffer solution of potassium phosphate dibasic (pH 7, 0.01 M). The procedure was applied with satisfactory results to the analysis of these herbicides in Guadiana river water samples (Badajoz, Spain), allowing the detection of herbicide residues in the order of μg l −1, by using a solid-phase extraction (SPE) pre-concentration step.

Automated on-line in-tube solid-phase microextraction followed by liquid chromatography/electrospray ionization-mass spectrometry for the determination of chlorinated phenoxy acid herbicides in environmental waters.

A method for the determination of six chlorinated phenoxy acid herbicides in river water was developed using in-tube solid-phase microextraction (SPME) followed by liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS). In-tube SPME is an extraction technique for organic compounds in aqueous samples, in which analytes are extracted from a sample directly into an open tubular capillary by repeated draw/eject cycles of the sample solution. Simple mass spectra with strong signals corresponding to [M-H]- and [M-RCOOH]- were observed for all herbicides tested in this study. The best separation of these compounds was obtained with a C18 column using linear gradient elution with a mobile phase of acetonitrile-water containing 5 mmol l-1 dibutylamine acetate (DBA). To optimize the extraction of herbicides, several in-tube SPME parameters were examined. The optimum extraction conditions were 25 draw/eject cycles of 30 microliters of sample in 0.2% formic acid (pH 2) at a flow rate of 200 microliters min-1 using a DB-WAX capillary. The herbicides extracted by the capillary were easily desorbed by 10 microliters acetonitrile. Using in-tube SPME-LC/ESI-MS with time-scheduled selected ion monitoring, the calibration curves of herbicides were linear in the range 0.05-50 ng ml-1 with correlation coefficients above 0.999. This method was successfully applied to the analysis of river water samples without interference peaks. The limit of quantification was in the range 0.02-0.06 ng ml-1 and the limit of detection (S/N = 3) was in the range 0.005-0.03 ng ml-1. The repeatability and reproducibility were in the range 2.5-4.1% and 6.2-9.1%, respectively.

Reflectometry Interference Spectroscopy in Detection of Hepatitis B Surface Antigen

Optical biosensors are of increasing interest for real-time detection of analytes without the use of additional labeled reagents. The sensing system is based on different interfacial physical properties that change upon the binding reaction. Combining high sensitivity and selectivity, label-free biosensors have the potential to provide low-cost detection and measurement technology for accurate and highly specific quantification of low-concentration analytes. Reflectometry interference spectroscopy (RIfS) is such a typical optical system that has been systematically developed and investigated by Brecht et al. (1). Based on the white-light interference effects occurring at thin transparent films, RIfS has shown high precision and high stability in monitoring the change of optical thickness attributable to interfacial molecular interaction and has been shown to be a useful approach for the detection of herbicides in river water and hydrocarbons in air (1)(2). At present, we are trying to find possible applications of RIfS in clinical diagnosis. ELISAs, the widely used label immunoassays in clinical laboratories, have inherent drawbacks, such as numerous pipetting and incubation steps. Additionally, the technique does not always show dose dependence in an extensive concentration range of analytes, exemplified by …

Rapid target analysis of microcontaminants in water by on-line single-short-column liquid chromatography combined with atmospheric pressure chemical ionization ion-trap mass spectrometry

The applicability of trace enrichment and separation of microcontaminants on a single 10×2 mm I.D. high-pressure-packed liquid chromatography (LC) column, combined on-line with an atmospheric pressure chemical ionization (APCI)–ion-trap tandem mass spectrometry (MS–MS) instrument was studied for the target analysis of herbicides in river water. The total analysis time was 15–20 min. With the on-line short-column LC–MS–MS method, detection limits of 0.1–1 μg/l can be achieved using only 4 ml of river water. However, the results obtained for a mixture of six triazines were considerably better than those for a mixture of eight phenylureas. An attempt is made to explain this difference on the basis of various processes that occur within the ion trap and the measurement procedure itself.

Rapid target analysis of microcontaminants in water by on-line single-short-column liquid chromatography combined with atmospheric pressure chemical ionization tandem mass spectrometry

The applicability of trace enrichment and separation of microcontaminants on a 10 mm×2 mm I.D. high-pressure packed (8 μm C18 bonded silica or 10–15 μm PLRP-S) column combined on-line with an atmospheric pressure chemical ionization MS–MS system is demonstrated for the target analysis of herbicides in river water. Tailor-made procedures are obtained for a limited number of analytes by tuning the chromatographic efficiency of the short LC column and the specificity of tandem MS, in order to minimize the analysis time. With the on-line short-column LC–MS–MS method, good linearity is obtained for the herbicides in the range of 0.1–10 μg/l. The relative standard deviations of peak areas are less than 5% and, with only 4-ml samples, detection limits of 0.01–0.1 μg/l can be achieved. The total analysis time is 10–15 min. The 10 mm×2 mm I.D. LC columns packed with 8 μm particles show good stability and can be used for at least 40 analyses. Target compound analyses of river water allowed the confirmation of the presence of herbicides such as diuron, simazine, atrazine and terbutylazine at sub-μg/l levels.

Identification of herbicides in river water using on-line trace enrichment combined with column liquid chromatography-Fourier-transform infrared spectrometry

Trace enrichment of herbicides on a 10×2.0 mm I.D. precolumn packed with Polygosil C 18 material, was combined on-line with column liquid chromatography-Fourier-transform infrared spectrometry (LC-FT-IR). The isocratic LC separation was carried out on a 200×2.1 mm I.D Rosil C 18 column using acetonitrile-phosphate buffer as eluent. The LC-FT-IR coupling was based on post-column on-line liquid-liquid extraction and solvent elimination, followed by FT-IR microscopy. The feasibility of the complete system was demonstrated by analysing river water spiked with triazines and phenylureas at the low-μg/l level. Identifiable spectra were obtained for all analytes, which included several isomers. Using 50–100 ml water samples, the identification limit for the herbicides typically was 1 μg/l. The usefulness of six spectral library search algorithms to correctly identify the recorded spectra was tested. A Peak-Search routine which is based on the matching of peak frequencies alone was found to be the most suitable to identify the analytes at the trace level.

Monitoring of herbicides in river water by gas chromatography-mass spectrometry and solid-phase extraction

A gas chromatography-mass spectrometric method was developed to determine concentrations of herbicides in both the dissolved phases and the suspended phase of river water. The target herbicides were 2-amino-3-chloro-1,4-naphthoquinone, alachlor, benfluralin, bifenox, bromobutide, the debromo form of bromobutide, butachlor, butamifos, chlomethoxyfen, chlornitrofen, chlorpropham, dimepiperate, dimethametryn, dithiopyr, esprocarb, MCPA-ethyl, MCPA-thioethyl, mefenacet, molinate, naproanilide, oxadiazon, pendimethalin, piperophos, pretilachlor, prometryn, simetryn, thiobencard and trifluralin. The herbicides in filtered river water were extracted with styrene-divinylbenzene copolymer and were eluted with acetone. The herbicides on suspended substances were extracted ultrasonically with acetone. Recoveries of the herbicides on the overall performance of this method were 81.6% to 128% from filtered river water and 80.0% to 110% from suspended substances. The minimum detectable concentrations in water and suspended substances ranged from 0.01 μg l −1 to 0.02 μ g l −1 and 0.05 μ g −1 to 0.1 μg g −1, respectively. This method was successfully applied to monitoring herbicides in river water.

Dissipation of 2,4-D glyphosate and paraquat in river water

Dissipation of herbicides in river water was determined by adding different concentrations of 2,4-D, glyphosate and paraquat to samples of river water. A small variation of dissipation of radioactivity for14C-2,4-D in higher and lower concentrations and in different samples of river water was found. But about half the radioactivity disappeared from water samples of original glyphosate concentration at 100 mg L−1 and, in the case of 100 μg L−1, only 11 to 22% remained in the samples of river water after 56 d incubation except the sample from Hsin-Tien River. More than 80% of paraquat remained in water samples. Determination of octanol-water partition coefficient (Kow) showed a large difference in amounts of 2,4-D partitioned in water phase at different pH values, 97.4% at the higher pH of ionic state and 5.2% at the lower pH of molecular state, implying that pH value of water might affect the bioaccumulation process of 2,4-D. The result showed that 95.0% of glyphosate present in water phase in ionic form (higher pH) and 82.3% in molecular form (lower pH), indicating that glyphosate might have no affect on the biomagnification, since most of glyphosate could be excreted with water by organisms.

Fully automated sample handling system for liquid chromatography based on pre-column technology and automated cartridge exchange

The design of an automated cartridge exchange module for on-line sample handling in liquid chromatography is described. When combined with a low-cost purge pump, a solvent selection valve and an auto-sampler, a fully automated sample handling system is obtained. Samples are sorbed on a disposable cartridge packed with 40 μm octyl-bonded silica, purged for clean-up and eluted on-line to the analytical column. Unattended operation of the system is demonstrated for various examples, i.e., the determination of anti-epileptic drugs in serum, an anti-cancer drug in plasma, barbiturates in urine, phenylurea herbicides in river water and caffeine in a soft drink.