Deisopropylatrazine Research Articles

Evaluation of sequential injection chromatography for reversed phase separation of triazine herbicides exploiting monolithic and core–shell columns

This paper describes the development of reversed phase sequential injection chromatography (SIC) methods for separation of simazine (SIM) and atrazine (AT), as well as their metabolites deethylatrazine (DEA), deisopropylatrazine (DIA) and hydroxyatrazine (HAT) exploiting silica based monolithic (50×4.6mm) and core–shell (30×4.6mm, 2.7µm particles) columns. The separation was made by stepwise elution with two mobile phases: MP1 composed of 15:85 (v/v) acetonitrile: 2.5mmolL−1 acetic acid/ammonium acetate buffer (pH 4.2), and MP2, composed of 35:65 (v/v) acetonitrile: 2.5mmolL−1 acetic acid/ammonium acetate buffer (pH 4.2).The less hydrophobic compounds (DIA, HAT and DEA) eluted with MP1, whereas SIM and AT eluted with MP2. The method using core–shell column exhibited better chromatographic efficiency compared with monolithic column for separation of SIM and AT, but failed to provide base line separation of DIA and HAT. The proposed composition of mobile phases enabled the monolithic column to separate all the studied compounds with resolution >2.3 at flow rate of 35µLs−1 and sampling throughput of 8 analyses per hour, whereas in the core–shell the maximum flow rate allowed in the SIC system was 8µLs−1 (sampling throughput of 3 analyses per hour). The limits of detection were between 24µgL−1 (AT) and 40µgL−1 (DEA) using the monolithic column, and between 20µgL−1 (SIM) and 38µgL−1 (DEA) with the core–shell. Ultrasound-assisted extraction (80:20v/v acetonitrile:water) of a soil sample enriched with the five triazines (250, 500 and 1000µgkg−1) resulted recoveries between 51% and 121% of the spiked concentrations.

Simultaneous determination of atrazine and metabolites (DIA and DEA) in natural water by multivariate electronic spectroscopy

A simple and rapid analytical method involving solid-phase extraction (SPE) and multivariate electronic spectroscopy for the determination of atrazine (ATZ) and its main metabolites desethylatrazine (DEA) and deisopropylatrazine (DIA) in aqueous solution was proposed. The predictive capability of the multivariate method developed by partial least squares regression was satisfactory, allowing mean errors between 0.33 and 10% in the simultaneous determination of ATZ, DIA and DEA in aqueous solution. The SPE procedure was optimized by factorial design, using ATZ as a model substrate. Under optimized experimental conditions, the recoveries of ATZ from aqueous standard solutions ranged from 83 to 116%. The developed method was applied in the analysis of spiked natural waters (river and spring) with recoveries in the range of 73–115% for ATZ in spring water. In the analysis of these complex samples, an important matrix effect was observed probably because of significant effects in both the extraction and quantification processes. Although the multivariate spectroscopy in the analysis of natural waters was largely dependent on the application of preliminary cleanup techniques guided to the removal of organic matter, the SPE–UV–PLS method was simple, fast and operated with low running costs.

Monitoring of atrazine biodegradation by Pleurotus ostreatus INCQS 40310 through the simultaneous analysis of atrazine and its derivatives by HPLC

Atrazine is a widely used herbicide on crops of major economic relevance such as corn and sugarcane. The widespread use of this herbicide could result in its accumulation in, or contamination of environmental niches. It is important to emphasize that not only atrazine but also its derivatives should be monitored. The aim of this study was to develop an appropriate methodology for simultaneous separation of atrazine (ATZ) and its derivatives, desethylatrazine (DEA), deisopropylatrazine (DIA), hydroxyatrazine (HA), desethyldeisopropylatrazine (DEDIA), desethylhydroxyatrazine (DEHA), and deisopropylhydroxyatrazine (DIHA) using high-performance liquid chromatography (HPLC). HPLC analyses were performed under gradient elution mode using a Shim-pack VP ODS C18 (250 × 4.6 mm, 4.6 μm) column, 5 mmol.L− 1 of sodium phosphate buffer (pH 7.2) and acetonitrile as the mobile phase at a flow rate of 1 mL.min− 1 and 25°C. Detection was monitored at 221 nm. Some validation parameters, such as selectivity, linearity, precision, accuracy, limit of detection and limit of quantification were evaluated for analyses of atrazine, DEA, and DEDIA. The method was successfully applied to the detection of DEA and DIA, the main degradation products observed after 15 days of incubation in the presence of Pleurotus ostreatus INCQS 40310. The formation of DEA and DIA was unequivocally confirmed by GC-MS.

Reliable and Sensitive SPE-HPLC-DAD Screening of Endocrine Disruptors Atrazine, Simazine and their Major Multiresidues in Natural Surface Waters: Analytical Validation and Robustness Study Perfomance

An analytical method combining off-line solid phase extraction (SPE) and reversed phase high performance liquid chromatography (HPLC) has been developed for simultaneous determination of six herbicides. The compounds analyzed in natural surface water samples, were: the herbicides atrazine (AT), simazine (SI) and their major dealkylated and hydroxylated degradation products such as deisopropyl-atrazine (DIA), deethyl-atrazine (DEA), hydroxyl-atrazine (H-AT) and hydroxyl-simazine (H-SI), all of them with herbicide activity too. As optimum conditions, a Kromasil C18 column as stationary phase, a mixture of acetonitrile and phosphate buffer pH 7.0 as mobile phase in gradient elution mode and 215 nm as measuring wavelength, were selected. A polymeric cartridge (Bond-Elut ENV-1000 mg) was used for a SPE procedure. The optimized off-line SPE HPLC-DAD method was evaluated in terms of validation and robustness procedure, obtaining among other parameters, limits of quantification between 81 and 100 ng L-1, considering the enrichment factor for all of the studied herbicides. The proposed method was successfully applied to the screening of herbicides in natural surface water samples from different locations in the 23th aquifer (Albacete, Spain).

Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil

Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microorganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster metabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

Photochemical degradation of atrazine in UV and UV/H2O2 process: pathways and toxic effects of products

The degradation of atrazine in aqueous solution by UV or UV/H2O2 processes, and the toxic effects of the degradation products were explored. The mineralization of atrazine was not observed in the UV irradiation process, resulting in the production of hydroxyatrazine (OIET) as the final product. In the UV/H2O2 process, the final product was ammeline (OAAT), which was obtained by two different pathways of reaction: dechlorination followed by hydroxylation, and the de-alkylation of atrazine. The by-products of the reaction of dechlorination followed by hydroxylation were OIET and hydroxydeethyl atrazine (OIAT), and those of de-alkylation were deisopropyl atrazine (CEAT), deethyl atrazine (CIAT), and deethyldeisopropyl atrazine (CAAT). OIAT and OAAT appeared to be quite stable in the degradation of atrazine by the UV/H2O2 process. In a toxicity test using Daphnia magna, the acute toxic unit (TUa) was less than 1 of TUa (100/EC50, %) in the UV/H2O2 process after 30 min of reaction time, while 1.2 to 1.3 of TUa was observed in the UV process. The TUa values of atrazine and the degradation products have the following decreasing order: OIET> Atrazine> CEAT≈CIAT> CAAT. OIAT and OAAT did not show any toxic effects.

Online Sequential-Injection Chromatography with Stepwise Gradient Elution: A Tool for Studying the Simultaneous Adsorption of Herbicides on Soil and Soil Components

The adsorption of triazine herbicides simazine (SIM), atrazine (ATR), and propazine (PRO) as well as the metabolites deisopropylatrazine (DIA), deethylatrazine (DEA), and 2-hydroxyatrazine (HAT) on soil, humic acid, and soil modified with humic acidic was studied by sequential-injection chromatography with UV detection at 223 nm. An online monitoring system was assembled, which was composed of a tangential filter and a peristaltic pump for the circulation of the soil (25 g L(-1)) or humic acid (2.5 g L(-1)) suspensions. A stepwise gradient elution separated the compounds using three mobile phases whose compositions were 28, 40, and 50% (v v(-1)) methanol in 1.25 mmol L(-1) ammonium acetate buffer, pH 4.7. The sampling throughput was about six analyses per hour; the linear dynamic range was between 100 and 1000 μg L(-1) for all of the studied compounds. The detection limits varied from 9 μg L(-1) for ATR to 36 μg L(-1) for DEA. At contact times <2 h, humic acid was the material with a higher adsorptive capacity (from 1470 ± 43 μg g(-1) for DIA to 2380 ± 51 μg g(-1) for PRO). In soil, HAT exhibited the highest adsorption (23.8 ± 0.2 μg g(-1)). The presence of humic acid in the soil increased the adsorption of ATR (14 ± 1 to 23 ± 2 μg g(-1)) and PRO (21.5 ± 0.5 to 24.0 ± 0.2 μg g(-1)), decreased the adsorption of HAT (23.8 ± 0.2 to 18 ± 2 μg g(-1)), and did not affect DIA and DEA. The adsorption of SIM was negligible in all of the sorbents studied. Simazine is the herbicide with the greatest potential for leaching to water bodies followed by DEA and DIA.

Natural wastes rich in terpenes and their relevance in the matrix of an on-farm biopurification system for the biodegradation of atrazine

A preliminary assay was performed to evaluate if natural wastes of low cost and rich in terpenes, such as pine needles, eucalyptus leaves and orange peels, added individually (5% w/w) into a microcosm simulating the matrix (peat based biomixture) of an on-farm biopurification system can be used to enhance the biodegradation of atrazine (ATZ) at 10 and 20 mg of active ingredient (a.i) of ATZ per kg of biomixture (mg a.i kg−1) and their enzyme activities. Accumulation of the degradation products deisopropylatrazine (DIA), deethylatrazine (DEA) and hydroxyatrazine (HA) were evaluated, and the volatile compounds emitted from the biomixture were also monitored. Addition of natural wastes allowed for a higher rate of biotransformation at both the ATZ concentrations evaluated. However, significant differences were observed with the addition of the orange peels (98%) and the eucalyptus leaves (95%) when compared to the control. ATZ biotransformation was not enhanced at either concentration when pine needles were added, but instead, this addition resulted in a decrease of the degradation efficiency compared with the control. The DIA, DEA and HA metabolites were detected in all treatments without clear formation patterns. Enzyme activities were negatively affected, especially following the addition of pine needles or eucalyptus leaves. However, the entire enzyme activities evaluated recovered quickly. In conclusion, the results obtained from this study demonstrated the relevance of using natural wastes rich in terpenes in a peat-based biomixture of a biopurification system to potentially enhance the ATZ biodegradation.

Extraction method for the determination of atrazine, deethylatrazine, and deisopropylatrazine in agricultural soil using factorial design

An optimization procedure for the extraction of the herbicide atrazine (AT), and the main degradation products deethylatrazine (DEA) and deisopropylatrazine (DIA) from an oxisol soil sample was carried out, for a soil from the Southwest of Paraná State in Brazil, where AT is among the most largely employed herbicide. A comparison between shaking and ultrasound extraction was performed, to define a simple and fast extraction procedure, followed by the quantification using high performance liquid chromatography. It is important to inform that a factorial planning was employed, that was very important to define the best conditions of extraction by shaking. Appropriate recovery values were observed using soil samples from three different depths, as well as the relative standard deviation, suggesting the possibility to employ the proposed extraction method for quantification of AT, DEA and DIA in oxisol samples.

Impact of Long-Term Atrazine Use on Groundwater Safety in Jilin Province, China

The long-lasting application of representative herbicide atrazine (ATR) has given rise to the accumulation of its residues in the groundwater. To investigate the impact of long-term ATR use on groundwater safety, the residues of ATR and its metabolites, desethylatrazine (DEA), deisopropylatrazine (DIA) and hydroxyatrazine (HA) were monitored in groundwater and top soil at the major corn growing region of Qian'an and Gongzhuling in Jilin Province, China. The residues of the target compounds were analyzed by UPLC-MS/MS. The limits of detection (LODs) of ATR, DEA, DIA, and HA were 0.5, 0.5, 5, and 0.5 ng L−1 in groundwater and 0.33, 0.33, 3.3, and 0.33 μg kg−1 in soil. The target compounds were found in 94% of groundwater samples and 100% of soil samples. The compounds detected most frequently in groundwater were ATR (89%), DEA (64%) and HA (17%), whereas in soil were ATR (97%), DEA (36%) and HA (97%). DIA was not detected in any determined groundwater and soil sample. Average residues were 106.8 ng L−1 for ATR, 0.9 ng L−1 for DEA and 0.3 ng L−1 for HA in groundwater, whereas 11.1 μg kg−1 for ATR, 0.4 μg kg−1 for DEA and 7.8 μg kg−1 for HA in soil. ATR residues detected in groundwater samples were below standards for drinking water quality (GB5749-2006, 2 μg L−1), while the total residues of ATR and its chloro-s-triazine metabolites (DEA and DIA) were below current WHO (World Health Organization) guideline value (GV, 0.1 mg L−1). In addition, concentrations of HA in groundwater were determined below current WHO GV (0.2 mg L−1). The results indicated that ATR is safe to be used in Jilin Province under the current application scheme. However, total residues of ATR and DEA were detected in nearly all wells, thus, it is necessary to pay attention on groundwater monitoring for ATR and its metabolites.

Effects of carbon amendment on in situ atrazine degradation and total microbial biomass

This study elucidates the effects of carbon amendment on metabolic degradation of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) and total microbial biomass in soil. Degradation of 14C-ring-labelled atrazine was monitored in laboratory incubations of soils supplemented with 0, 10, 100 and 1000 μg g−1 sucrose concentrations. An experiment to determine the effect of carbon amendment on total microbial biomass and soil respiration was carried out with different concentrations of sucrose and non-labelled atrazine. The soils were incubated at a constant temperature and constant soil moisture at water potential of −15 kPa and a soil density of 1.3 g cm−3. Mineralization of 14C-ring-labelled atrazine was monitored continuously over a period of 59 d in the first experiment. The CO2 production was monitored for 62 d in the second experiment and microbial biomass determined at the end of the incubation period. The addition of 1000 μg g−1 sucrose reduced atrazine mineralization to 43.5% compared to 51.7% of the applied amount for the treatment without sucrose. The addition of 1000 μg g−1 sucrose modified the transformation products to 1.08 μg g−1 deisopropylatrazine (DIA), 0.32 μg g−1 desethylatrazine (DEA) and 0.18 μg g−1 deisopropyl-2-hydroxyatrazine (OH-DIA). Treatment without sucrose resulted in formation of 0.64 μg g−1 hydroxyatrazine (HA), 0.28 μg g−1 DIA and 0.20 μg g−1 OH-DIA. Atrazine dealkylation was enhanced in treatments with 100 and 1000 μg g−1 of sucrose added. HA metabolite was formed in the control (no sucrose) and in the presence of 10 μg g−1 of sucrose, whereas DEA was only detected in treatment with 1000 μg g−1 sucrose. Results indicate that total microbial biomass increased significantly (P < 0.001) with the addition of 1000 μg g−1 sucrose.

Extraction Method for the Determination of Atrazine, Deethylatrazine, and Deisopropylatrazine in Agricultural Soil Using Factorial Design

An optimization procedure for the extraction of the herbicide atrazine (AT), and the main degradation products deethylatrazine (DEA) and deisopropylatrazine (DIA) from an oxisol soil sample was carried out, for a soil from the Southwest of Parana State in Brazil, where AT is among the most largely employed herbicide. A comparison between shaking and ultrasound extraction was performed, to define a simple and fast extraction procedure, followed by the quantification using high performance liquid chromatography. It is important to inform that a factorial planning was employed, that was very important to define the best conditions of extraction by shaking. Appropriate recovery values were observed using soil samples from three different depths, as well as the relative standard deviation, suggesting the possibility to employ the proposed extraction method for quantification of AT, DEA and DIA in oxisol samples.

Monitoring of atrazine and its metabolites in groundwaters of the Republic of Serbia

The intensive use of atrazine herbicides in the Republic of Serbia during recent decades has led to the accumulation of residues of atrazine and its metabolites in the environment, which endangers groundwater. With the objective to check the presence of atrazine and its metabolites deethylatrazine (DEA) and deisopropylatrazine (DIA) in the groundwater, the monitoring programme was carried out over the period from 2007 to 2009 in the localities where the atrazine-based herbicides were intensively applied for a number of years. Samples were taken from 327 localities, in total there were 1408 samples of groundwater of the first welling-up collected. The atrazine and its metabolites were extracted with methanol by means of ENVI-C18 (47mm) disc, and the residue level of the studied compounds was analyzed with gas chromatography-mass spectrometry (GC-MS). In the most of groundwater samples collected from agricultural regions, average value of all tested analytes was above 0.1 ?g/dm3. The highest values of atrazine and its metabolites were in the localities that is known for intensive maize production and in the areas of this region under orchards and vineyards, where atrazine was used in large quantities. The average values of content of this active substance in analyzed samples are the result of intensive and long-term usage of this group of herbicides, as well as the high level of groundwater in this region.

Fate of atrazine in switchgrass–soil column system

Atrazine, a broad-leaf herbicide, has been used widely to control weeds in corn and other crops for several decades and its extensive used has led to widespread contamination of soils and water bodies. Phytoremediation with switchgrass and other native prairie grasses is one strategy that has been suggested to lessen the impact of atrazine in the environment. The goal of this study is to characterize: (1) the uptake of atrazine into above-ground switchgrass biomass; and (2) the degradation and transformation of atrazine over time. A fate study was performed using mature switchgrass columns treated with an artificially-created agricultural runoff containing 16ppm atrazine. Soil samples and above-ground biomass samples were taken from each column and analyzed for the presence of atrazine and its chlorinated metabolites. Levels of atrazine in both soil and plant material were detectable through the first 2weeks of the experiment but were below the limit of detection by Day 21. Levels of deethylatrazine (DEA) and didealkylatrazine (DDA) were detected in soil and plant tissue intermittently over the course of the study, deisopropylatrazine (DIA) was not detected at any time point. A radiolabel study using [14C]atrazine was undertaken to observe uptake and degradation of atrazine with more sensitivity. Switchgrass columns were treated with a 4ppm atrazine solution, and above-ground biomass samples were collected and analyzed using HPLC and liquid scintillation counting. Atrazine, DEA, and DIA were detected as soon as 1d following treatment. Two other metabolites, DDA and cyanuric acid, were detected at later time points, while hydroxyatrazine was not detected at all. The percentage of atrazine was observed to decrease over the course of the study while the percentages of the metabolites increased. Switchgrass plants appeared to exhibit a threshold in regard to the amount of atrazine taken up by the plants; levels of atrazine in leaf material peaked between Days 3 and 4 in both studies.

Use of time-of-flight mass spectrometry for large screening of organic pollutants in surface waters and soils from a rice production area in Colombia

The irrigate district of Usosaldaña, an important agricultural area in Colombia mainly devoted to rice crop production, is subjected to an intensive use of pesticides. Monitoring these compounds is necessary to know the impact of phytosanitary products in the different environmental compartments. In this work, surface water and soil samples from different sites of this area have been analyzed by applying an analytical methodology for large screening based on the use of time-of-flight mass spectrometry (TOF MS) hyphenated to liquid chromatography (LC) and gas chromatography (GC). Several pesticides were detected and unequivocally identified, such as the herbicides atrazine, diuron or clomazone. Some of their main metabolites and/or transformation products (TPs) like deethylatrazine (DEA), deisopropylatrazine (DIA) and 3,4-dichloroaniline were also identified in the samples. Among fungicides, carbendazim, azoxystrobin, propiconazole and epoxiconazole were the most frequently detected. Insecticides such as thiacloprid, or p,p′-DDT metabolites (p,p′-DDD and p,p′-DDE) were also found. Thanks to the accurate-mass full-spectrum acquisition in TOF MS it was feasible to widen the number of compounds to be investigated to other families of contaminants. This allowed the detection of emerging contaminants, such as the antioxidant 3,5-di-tertbutyl-4-hydroxy-toluene (BHT), its metabolite 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), or the solar filter benzophenone, among others.

Currently used pesticides in water matrices in Central-Western Brazil

This study provides data on the presence of the pesticides atrazine, chlorpyrifos, α-endosulfan, β-endosulfan, flutriafol, malathion and metolachlor in water matrices in urban and rural areas of Campo Verde and Lucas do Rio Verde Cities, Mato Grosso State, Brazil. Surface, rain, and groundwater samples were collected in the rainy and dry seasons during 2007 and 2008 in these important grain-producing areas. The findings revealed a higher diversity of compounds and frequency of detection in the rain water than in surface and groundwater samples. Concentrations of atrazine, endosulfan and malathion above those permitted by Brazilian regulations were found in some surface and groundwater samples, and the degradation products DIA (deisopropylatrazine) and endosulfan sulfate, rather than their parental compounds, were found at higher levels in some samples. Our findings show the vulnerability of water systems in these areas and point to the risk of pesticide contamination in important headwater streams.

Terbuthylazine and other triazines in Italian water resources

The concern on the presence of pesticides in Italian water resources historically broke out around 1980 after severe episodes of ambient, raw water and drinking water contamination due to some herbicides, atrazine (ATR), its metabolites desethylatrazine (DEA) and deisopropylatrazine (DIA), simazine, cyanazine, bentazone, molinate, which affected mainly the maize, grain and rice producing floodplains and karst areas of the northern Regions. Due to the risks of human exposure, in the early 1990 the use of atrazine was banned in Italy and was replaced by terbuthylazine (TERB). In a few years, TERB became a chemical of concern, together with its main metabolite desethylterbuthylazine (DET), because of alerting detections in surface and groundwater resources. Up to now, the risk of contamination of water resources by TERB, DET, DEA and, in some extent ATR, is of relevance in Italy due to their present and past wide employment in agriculture, the discharges or seepages in particularly vulnerable areas, their unfavorable intrinsic properties, e.g. poor sorption and high persistence, their mobility by drift, leaching and runoff in vadose zones, aquifers and surface water. So, unsurprisingly, results from national monitoring of ambient water and raw water indicate that TERB, DET, DEA and residual ATR, despite its withdrawal, are detected at remarkable frequencies and, sometimes, at levels higher than pesticide quality standards under the Italian Decrees for the protection of surface water (specifically, raw waters doomed at the drinking water abstraction), groundwater and drinking water (tap water), that is 0.1–0.5μg/l for individual pesticides and for total pesticides, respectively, including relevant metabolites. On the other hand, in these last years, the control measures in drinking water production adopted by the waterworks Companies and the regional and central health Authorities, also in the view of the recent WHO approaches under the Water Safety Plans, ensure that levels of any pesticide residue (also involving TERB, DET, DEA, ATR) in finished tap water meet parametric values for pesticides. Therefore, in these last years, no derogation to the parametric values for drinking water has been required. The aim of this paper is to contribute to widen the knowledge on the water impact of these important water pollutants giving sound details on present usages, levels and frequencies of detection in water bodies in Italy, on their key chemiodynamic properties, e.g. soil half-lives (DT50) and soil to organic carbon partition (Koc) available in the open literature, particularly for TERB metabolites, and some details on legal provision adopted at the national level. In fact, a more effective protection of water supplies, particularly against TERB and DET, has been pursued in the late 2000s by the Italian Health Ministry through the adoption of consistent provisions aimed at mitigating emissions of TERB in routine agricultural activities, and by the Italian Ministry of the Environment through the adoption of specific Environmental Quality Standards for TERB and its metabolite DET, ATR, SIM for the protection of surface waters.

Leaching of Br−, metolachlor, alachlor, atrazine, deethylatrazine and deisopropylatrazine in clayey vadoze zone: A field scale experiment in north-east Greece

An extensive four-year research program has been carried out to explore and acquire knowledge about the fundamental agricultural practices and processes affecting the mobility and bioavailability of pesticides in soils under semi-arid Mediterranean conditions. Pesticide leaching was studied under field conditions at five different depths using suction cups. Monitoring of metolachlor, alachlor, atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and bromide ions in soil water, as well as dye patterns made apparent the significant role of preferential flow to the mobility of the studied compounds. Irrespective to their adsorption capacities and degradation rates, atrazine, metolachlor and bromide ions were simultaneously detected to 160 cm depth. Following 40 mm irrigation, just after their application, both alachlor and atrazine were leached to 160 cm depth within 18 h, giving maximum concentrations of 211 and 199 μg L−1, respectively. Metolachlor was also detected in all depth when its application was followed by a rainfall event (50 mm) two weeks after its application. The greatest concentrations of atrazine, alachlor and metolachlor in soil water were 1795, 1166 and 845 μg L−1, respectively. The greatest concentrations of atrazine’s degradation products (both DEA and DIA) appeared later in the season compared to the parent compound. Metolachlor exhibited the greatest persistence with concentrations up to 10 μg L−1 appearing in soil water 18 months after its application. Brilliant blue application followed by 40 mm irrigation clearly depict multi-branching network of preferential flow paths allowing the fast flow of the dye down to 150 cm within 24 h. This network was created by soil cracks caused by shrinking of dry soils, earthworms and plant roots. Chromatographic flow of the stained soil solution was evident only in the upper 10–15 cm of soil.

An automatic field sampler utilising supported liquid membrane (SLM) for on-site extraction of s-triazine herbicides and degradation products: applied to an agricultural region of Ethiopia

A portable and time-integrating field sampler based on the supported liquid membrane (SLM) extraction technique was constructed. Using two programmable syringe pumps and one programmable valve, the sampler could carry out automatic unattended extraction for up to seven extracts, combining the steps of sampling, trace enrichment and clean-up. The sampler was applied to the extraction of four s-triazine herbicides (atrazine, cyanazine, prometryn and terbutryn) and six major degradation products of s-triazines, including three dealkylated products (deethyl deisopropyl atrazine (DDA), deisopropyl atrazine DIA and deethyl atrazine (DEA)) and three hydroxylated products (hydroxy atrazine (ATOH), hydroxy propazine (PROH) and hydroxy terbutylazine (TZOH)). The donor solution was obtained by mixing sample and buffer, consisting of 1 M phosphate buffer at pH 7.0 and 1.7 M NaCl, in the ratio of 19 : 1 (v/v). Extraction was performed by continuously pumping 10 mL portions of donor along the SLM until 3 L of sample had been extracted. The SLM consisted of di-n-hexylether and the acceptor was 1 M HCl. After extract collection, extracts were neutralised with NaOH and buffered with phosphate. Extracts were analysed with HPLC, using a gradient elution consisting of 3.5 mM phosphate and acetonitrile and UV-detection at 220 nm. Enrichment factors in reagent water ranged from 1.3 (for DIA) to 2739 (for terbutryn). The developed field sampler was tested by carrying out 24-h time-weighted on-site extraction of the ten s-triazine target compounds in Hawassa Lake and its tributary river, located in the agricultural region of the Southern Rift Valley of Ethiopia. Atrazine, cyanazine and terbutryn were generally below the method detection limit, while prometryn was frequently found. Overall, s-triazines were not persistent in the studied environment and degradation products of s-triazines were found in higher concentrations than the parent herbicides in both the river and the lake.

Determination of atrazine and degradation products in Luxembourgish drinking water: origin and fate of potential endocrine-disrupting pesticides

Several pesticides have been hypothesized to act as endocrine-disrupting compounds, exhibiting hormonal activity and perturbing normal physiological functions. Among these, especially s-triazine herbicides have received increased attention. Despite being banned in many countries, including the European Union, atrazine is still the world's most widely used herbicide. Despite its discontinued use, considerable concentrations of atrazine and its degradation products, mainly desethylatrazine (DEA) and deisopropylatrazine (DIA), are still found in the environment, including drinking water sources. The aim of this investigation was to study concentrations of especially s-triazine herbicides and major degradation products in drinking water, including spring water, tap water and bottled water in Luxembourg. Spring water (2007/2008/2009, n = 69/69/69), tap water (2008/2009, n = 19/26), and bottled water (2007/2008/2009, n = 5/13/7) were sampled at locations in Luxembourg and investigated for pesticides by LC-ESI-MS/MS. Atrazine was the predominant triazine, detectable in many spring water locations, tap and bottled water, ranging (mean) from 0–57 (9), 0–44 (4), and 0–4 (1) ng l−1, respectively. DEA and DIA in spring water ranged (mean) from 0–120 (19) and 0–27 (3) ng l−1, with higher concentrations from agricultural areas and low molar ratios of DEA:atrazine <0.5 and high ratios of atrazine:nitrate suggesting point-source contamination. Levels (mean) of DEA and DIA in tap water were 0–62 (14) and 0–6 (<1) ng l−1 and in bottled water 0–11 (2) and 0–7 (2) ng l−1. Simazine and other triazines were detected in traces (<5 ng l−1). Thus, the conducted monitoring suggested the presence of low concentrations of s-triazines in raw and finished water, presumably partly due to non-agricultural contamination, with concentrations being below thresholds advocated by the European Union Directive 98/83/EC.