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1.
The fate of selected pesticides (bentazone, isoproturon, DNOC, MCPP, dichlorprop and 2,4-D) and a metabolite (2,6-dichlorobenzamide (BAM)) was investigated under aerobic conditions in column experiments using aquifer material and low concentrations of pesticides (approximately 25 microg/l). A solute transport model accounting for kinetic sorption and degradation was used to estimate sorption and degradation parameters. Isoproturon and DNOC were significantly retarded by sorption, whereas the retardation of the phenoxy acids (MCPP, 2,4-D and dichlorprop), BAM and bentazone was very low. After lag periods of 16-33 days for the phenoxy acids and 80 days for DNOC, these pesticides were degraded quickly with 0.-order rate constants of 1.3-2.6 microg/l/day. None of the most probable degradation products were detected.  相似文献   

2.
In this work the development, validation and application of method using Solid Phase Microexctration (SPME) for the analyses of five pollutants (phenol, 2-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol and 4-chloro, 3-methyl phenol) in supplying water, using gas chromatography (GC) with flame ionization detector (FID) is described. The optimal conditions obtained for SPME were: fiber type: Poliacrylate (PA); extraction time: 40 minutes; extraction temperature: 70 degrees C; amount of salt added to sample (NaCl): 15%; desorption temperature: 8 minutes. The parameters studied in the method validation were: limit of detection (0.3 and 3.5 microg.L(- 1)); precision, measured by the variation coefficient (between 2.1 and 8.8%); calibration curve and linearity, by using the external standardization method (between 1 and 50 50 microg.L(- 1)). After the methodology development, samples of water collected in Atibaia River (S?o Paulo - Brazil) were analyzed, using the optimized methodology. Three water samples collected in the rain season showed a peak with retention time close to 4-chloro, 3 methyl phenol further analyzed by Gas Chromatography-Mass Spectrometry for the identity confirmation. In spite of the fact that none target compounds were found in the river water samples analyzed, the presence of two phenols different from those investigated (p-terc butyl phenol; butylated hydroxytoluene) were detected. These results together with the results of the limit of detection (that showed to be lower than the maximum concentration of phenols demanded by different environment control agencies), and the results of the validation, indicate the applicability of this method for the analysis of selected phenols in river water samples.  相似文献   

3.
Tran AT  Hyne RV  Doble P 《Chemosphere》2007,67(5):944-953
The present study describes the application of different extraction techniques for the preconcentration of ten commonly found acidic and non-acidic polar herbicides (2,4-D, atrazine, bensulfuron-methyl, clomazone, dicamba, diuron, MCPA, metolachlor, simazine and triclopyr) in the aqueous environment. Liquid-liquid extraction (LLE) with dichloromethane, solid-phase extraction (SPE) using Oasis HLB cartridges or SBD-XC Empore disks were compared for extraction efficiency of these herbicides in different matrices, especially water samples from contaminated agricultural drainage water containing high concentrations of particulate matter. Herbicides were separated and quantified by high performance liquid chromatography (HPLC) with an ultraviolet detector. SPE using SDB-XC Empore disks was applied to determine target herbicides in the Murrumbidgee Irrigation Area (NSW, Australia) during a two-week survey from October 2005 to November 2005. The daily aqueous concentrations of herbicides from 24-h composite samples detected at two sites increased after run-off from a storm event and were in the range of: 0.1-17.8 microg l(-1), < 0.1-0.9 microg l(-1) and 0.2-17.8 microg l(-1) at site 1; < 0.1-3.5 microg l(-1), < 0.1-0.2 microg l(-1) and < 0.2-3.2 microg l(-1) at site 2 for simazine, atrazine and diuron, respectively.  相似文献   

4.
In this work the development, validation and application of method using Solid Phase Microexctration (SPME) for the analyses of five pollutants (phenol, 2-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol and 4-chloro, 3-methyl phenol) in supplying water, using gas chromatography (GC) with flame ionization detector (FID) is described. The optimal conditions obtained for SPME were: fiber type: Poliacrylate (PA); extraction time: 40 minutes; extraction temperature: 70°C; amount of salt added to sample (NaCl): 15%; desorption temperature: 8 minutes. The parameters studied in the method validation were: limit of detection (0.3 and 3.5 μ g.L? 1); precision, measured by the variation coefficient (between 2.1 and 8.8%); calibration curve and linearity, by using the external standardization method (between 1 and 50 50 μ g.L? 1). After the methodology development, samples of water collected in Atibaia River (São Paulo - Brazil) were analyzed, using the optimized methodology. Three water samples collected in the rain season showed a peak with retention time close to 4-chloro, 3 methyl phenol further analyzed by Gas Chromatography-Mass Spectrometry for the identity confirmation. In spite of the fact that none target compounds were found in the river water samples analyzed, the presence of two phenols different from those investigated (p-terc butyl phenol; butylated hydroxytoluene) were detected. These results together with the results of the limit of detection (that showed to be lower than the maximum concentration of phenols demanded by different environment control agencies), and the results of the validation, indicate the applicability of this method for the analysis of selected phenols in river water samples.  相似文献   

5.
Solid phase micro extraction (SPME) was applied to the determination of selected trihalomethanes (THMs), chloroform, bromodichloromethane, dibromochloromethane, bromoform, in potable and recreational waters. The selected samples were environmentally significant due to mandatory limits imposed by regulatory agencies. Extraction of the analytes was performed using headspace SPME (fused silica fibre with a 100 microm poly(dimethylsiloxane coating) followed by thermal desorption at 220 degrees C and GC-MS analysis. A linear working range of 10-160 microg/l was established with relative standard deviations (%RSD) within the range, 0.9-19%. Limits of detection (LOD) were 1.0-2.8 microg/l. The highest THM concentration was 61.8 microg/l which was well within the proposed European Union directive of 100 microg/l. The total THMs determined in swimming pool waters ranged from 105-134 microg/l, with chloroform accounting for 84-86% of total THM.  相似文献   

6.
Residues of five pesticides in surface water were surveyed during 2001 and 2003 in the Traiguen river basin in Southern Chile. Simazine, hexazinone, 2,4-D, picloram herbicides and carbendazim fungicide were selected through a pesticide risk classification index. Six sampling stations along the river were set up based on agricultural and forestry land use. The water sampling was carried out before and after the pesticide application periods and in correspondence to some rain events. Pesticides were analyzed by HPLC with DAD detection in a multiresidue analysis. During 2001, in the first sampling campaign (March), the highest concentrations of pesticides were 3.0 microg l(-1) for simazine and hexazinone and 1.8 microg l(-1) for carbendazim. In the second sampling (September), the highest concentration were 9.7 microg l(-1) for 2,4-D, 0.3 microg l(-1) for picloram and 0.4 microg l(-1) for carbendazim. In the last sampling period (December), samples indicated contamination with carbendazim fungicide at levels of up to 1.2 microg l(-1). In sampling carried out on May 2003, no pesticides were detected. In October 2003, the highest concentrations of pesticides were 4.5 microg l(-1) for carbendazim and 2.9 microg l(-1) for 2,4-D. Data are discussed in function of land use and application periods of the products, showing a clear seasonal pattern pollution in the Traiguen river. Risk assessment for these pesticides was calculated by using a risk quotient (RQ = PNEC/PEC). For picloram the calculated RQ < was 0, which indicates that no adverse effects may occur due to the exposure to this herbicide in the Traiguen river basin. For 2,4-D, simazine, hexazinone, carbendazim RQ > 1, meaning that adverse effects could occur and it is necessary to reduce pesticide exposure in surface waters. It is recommended to continue with a pesticide monitoring program and the implementation of ecotoxicological testing with local and standardized species in order to consider the probability of effects occurrence, with less uncertainty. Thus, it will be more feasible to make some recommendations to regulatory agencies regarding the pesticide use.  相似文献   

7.
The biodegradation of selected priority acidic pesticides MCPP, MCPA, 2,4-D, 2,4-DP and bentazone and the acidic pharmaceutical diclofenac was investigated using a membrane bioreactor (MBR) and a fixed-bed bioreactor (FBBR). A pilot plant MBR was fed with raw water spiked with the selected compounds. The experiment was repeated every week during four weeks to enhance the adaptation of microorganisms. In order to further study the biodegradability of these compounds, degradation studies in a FBBR were carried out. All the samples were analysed by solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). The results indicate that in the MBR compounds except for bentazone were eliminated within the first day of the experiment at rates ranging from 44% to 85%. Comparing these results with the degradation rates in the FBBR showed that in the latter only MCPP, MCPA 2,4-D and 2,4-DP were degraded after a much longer adaptation phase of microorganisms.  相似文献   

8.
Three-dimensional reactive transport simulations were undertaken to study the sorption and degradation dynamics of three herbicides in a shallow aerobic aquifer with spatially variable pH during a 216 days injection experiment. Sorption of two phenoxy acids [(+/-)-2-(4-chloro-2-methylphenoxy) propanoic acid] (MCPP) and [(+/-)-2-(2,4-dichlorophenoxy)propanoic acid] (dichlorprop) was found to be negligible. Degradation of the phenoxy acids was rapid after an initial lag phase. Degradation of the phenoxy acids could only be reproduced satisfactorily by growth-linked microbial degradation. The model fit to the field data was slightly improved if degradation was assumed to be influenced by the local pH that was observed to increase with depth ( approximately 4.5--5.7). In the observed pH-range the nitroaromatic herbicide [2-Methyl-4,6-dinitrophenol] (DNOC) was partly dissociated (pK(a)=4.31) and present in both the neutral and ionized form. The model simulations demonstrated that most of the observed spatial variation in sorption of DNOC could be explained by assuming that only the neutral form of DNOC was subject to sorption. A varying flow field was observed during the injection experiment and the model simulations documented that this most likely resulted in different migration paths for DNOC and the non-sorbing solutes. The model simulations indicated that degradation of DNOC was an important process. The degradation rate of DNOC remained constant over time and was simulated adequately by first-order kinetics. Again, the model fit to field observation was slightly improved if local pH was assumed to influence the degradation rate. Only the maximum utilization rate was estimated from the field data, while the remaining degradation parameters where successfully transferred from the laboratory study.  相似文献   

9.
Four methods were developed for the analysis of fluroxypyr in soil samples from oil palm plantations. The first method involved the extraction of the herbicide with 0.05 M NaOH in methanol followed by purification using acid base partition. The concentrated material was subjected to derivatization and then cleaning process using a florisil column and finally analyzed by gas chromatography (GC) equipped with electron capture detector (ECD). By this method, the recovery of fluroxypyr from the spiked soil ranged from 70 to 104% with the minimum detection limit at 5 microg/kg. The second method involved solid liquid extraction of fluroxypyr using a horizontal shaker followed by quantification using high performance liquid chromatography (HPLC) equipped with UV detector. The recovery of fluroxypyr using this method, ranged from 80 to 120% when the soil was spiked with fluroxypyr at 0.1-0.2 microg/g soil. In the third method, the recovery of fluroxypyr was determined by solid liquid extraction using an ultrasonic bath. The recovery of fluroxypyr at spiking levels of 4-50 microg/L ranged from 88 to 98% with relative standard deviations of 3.0-5.8% with a minimum detection limit of 4 microg/kg. In the fourth method, fluroxypyr was extracted using the solid liquid extraction method followed by the cleaning up step with OASIS HLB (polyvinyl dibenzene). The recovery of fluroxypyr was between 91 and 95% with relative standard deviations of 4.2-6.2%, respectively. The limit of detection in method 4 was further improved to 1 pg/kg. When the weight of soil used was increased 4 fold, the recovery of fluroxypyr at spiking level of 1-50 microg/kg ranged from 82-107% with relative standard deviations of 0.5-4.7%.  相似文献   

10.
Zhou Y  Jiang Q  Peng Q  Xuan D  Qu W 《Chemosphere》2007,70(2):256-262
A new method, headspace solid-phase microextraction (HS-SPME) with in situ derivatization and gas chromatography-mass spectrometry (GC-MS), which was used for the determination of trace amount of pentachlorophenol (PCP) in human plasma was presented. The acetylation derivatization reaction was firstly optimized using a Doehlert design. Then a series of parameters relevant to the headspace SPME procedure, including fiber coating, extraction temperature, extraction time and salt addition, were optimized using a two-level full factorial design expanded further to a central composite design. The validation of method showed that the optimized method had good linearity (R(2)=0.999) within the concentration ranges 0.1-50.0ngml(-1), and was sensitive with the limit of detection of 0.02ngml(-1). Intra- and inter-day precision for pentachlorophenol in human plasma samples were not greater than 11.9% and 12.6%, respectively. The proposed method, to our knowledge, describes the first application of HS-SPME with GC-MS for analysis of PCP in blood plasma sample. Application of the method to real human plasma samples, PCP was successfully detected in some cases at concentration levels 1.2-6.3ngml(-1).  相似文献   

11.
The mobility of acid herbicide (4-chloro-2-methylphenoxy)acetic acid [MCPA] and 2-(4-chloro-2-methylphenoxy)propionic acid [MCPA] in soils of North-West Croatia has been studied by soil thin-layer chromatography (STLC). Mobility of MPCA and MCPP was influenced by the change in concentration of soluble salts and the effect of mineral composition of the system studied, i.e. content of kaolin and sand in soil thin layer. The objective of this work was also to investigate how the mobility of phenoxy herbicides MCPA and MCPP is altered by the presence of fertilizers when both coexist in soil as a result of human activity. It has been found that mobility of acidic herbicides increases with application of fertilizers especially on soil with low clay and low organic matter content.  相似文献   

12.
Multiple efforts have been directed towards optimized processes in which enzymes, like peroxidases, are used to remove phenolic compounds from polluted wastewater. Here we describe the use of peroxidase isoenzymes from tomato hairy roots, which were able to oxidise 2,4-dichlorophenol (2,4-DCP) and phenol from aqueous solutions. This could be an interesting alternative for the removal of these compounds from contaminated sites. We used different enzyme fractions: total peroxidases (TP), ionically bound to cell wall peroxidases (IBP), basic (BP) and acidic peroxidases (AP). We analyzed the optimum conditions of removal, the effect of Polyethyleneglycol (PEG-3350) on the process and on the enzyme activities, to obtain the maximum efficiency. The optimal H2O2 concentrations for 2,4-DCP and phenol removal were 1 and 0.1mM, respectively. TP, IBP and BP showed better removal efficiencies than AP, for both contaminants. The addition of different concentrations (10-100mg l(-1)) of PEG-3350 to solutions containing 2,4-DCP showed no effect on the removal efficiencies of the isoenzymes. However, PEG (100mg l(-1)) increased the removal efficiency of phenol by BP and IBP fractions. On the other hand, peroxidase activities from BP and IBP fractions were 3 and 13 times higher, respectively, than those detected for the same fractions in phenol treated solutions without PEG. The protective effect of PEG, which depends on the contaminant as well as of the enzyme fraction used, would be important to improve the removal efficiency of phenol by some peroxidase isoenzymes.  相似文献   

13.
Bioconcentration factors (BCF) for pentachlorophenol (PCP) and 2,4-dichlorophenol (2,4-DCP) in Japanese medaka (Oryzias latipes) were determined at five different concentrations of the chemicals, between 0.1 and 10 microg/l (PCP), 0.3 and 30 microg/l (2,4-DCP), in the ambient water. Medaka were exposed to each chemicals in a continuous-flow system during the embryonic development period and 60 days after hatching from eggs collected in the laboratory. Both the exposure time and the aqueous concentrations are much more realistic and closer to natural aquatic environments than those used in conventional BCF studies. The BCF values of PCP were from (4.9+/-2.8)x10(3) at the aqueous concentration of 0.074+/-0.028 microg/l to (2.1+/-1.4)x10(3) at 9.70+/-0.56 microg/l. The BCF value of 2,4-DCP were from (3.4+/-3.0)x10(2) at 0.235+/-0.060 microg/l to 92+/-27 at 27.3+/-1.6 microg/l. Generally, BCF values increased as the aqueous concentrations of PCP or 2,4-DCP decreased. This finding suggests that a relatively low and realistic aqueous concentration of these compounds is necessary to more accurately determine their BCF values in natural aquatic environments. Conventional BCF experiments at higher aqueous concentrations may underestimate the BCF values.  相似文献   

14.
A fast, simple and inexpensive method has been developed for the analysis of phenoxy acid herbicides: 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), 2-(4-chloro-o-tolyloxy)propionic acid (MCPP), 2-(4-aryloxyphenoxy)propionic acid (Fluazifop) and 2-(4-aryloxyphenoxy)propionic acid (Haloxyfop) in carrots and apples by liquid chromatography coupled to triple quadrupole mass spectrometry (LC/MS/MS). The compounds were analyzed by QuEChERS (quick, easy, cheap, effective, rugged, safe) methodology without cleanup.

The recoveries were performed at two spiked levels (0.05 and 0.5 mg/kg) for both matrices with six replicates for each level. The mean recoveries ranged from 70–92% for both apples and carrots. The precision of the method expressed as relative standard deviation (RSD%) was found to be in the range 3–15%. For all compounds, good linearity (r2 > 0.99) was obtained over the range of concentration from 0.05 μ g/mL to 0.5 μ g/mL, corresponding to the pesticide concentrations of 0.05 mg/kg and 0.5 mg/kg, respectively. The determination limits (LOQs) ranged from 0.01 ng/mL to 1.3 ng/mL in solvent, whereas, the LOQs calculated in matrix ranged from 0.05 ng/g to 21.0 ng/g for apples and from 0.06 ng/g to 10.2 ng/g for carrots. The developed methodology combines the advantages of both QuEChERS and LC/MS/MS producing a very rapid, sensitive and cheap method useful for the routine analytical laboratories.  相似文献   

15.
Ferrari S  Mandel F  Berset JD 《Chemosphere》2002,47(2):173-182
An analytical method was developed to determine quantitatively 1-hydroxypyrene (OHP) in bovine urine samples. The procedure includes an enzymatic hydrolysis to cleave the conjugated metabolite, an enrichment step using solid phase extraction with a non-polar rinse step and elution with dichloromethane. A final clean-up on silicagel was performed before high-performance liquid chromatography (HPLC) analysis and fluorescence detection. Alternatively, HPLC and electrospray ionization in the negative ion mode applying selective ion monitoring acquisition revealed to be a highly sensitive detection method allowing the quantitation of low pg of OHP in the urine samples. The method was successfully applied to the determination of OHP in bovine urine samples from animals living in urban and rural areas. Urine concentrations of OHP were significantly higher (median 8.6 microg l(-1)) of bovines living close to a highway.  相似文献   

16.
A new dynamic air sampling system was devised and evaluated in conjunction with solid phase microextraction (SPME) fiber materials for extracting odor-causing volatile organic compounds (VOCs) present in swine building environments. Utilizing a standard solution consisting of 11 compounds (i.e., volatile fatty acids, indoles, and phenol), sampling times, volumes, and flow rates were adjusted to establish optimal extraction conditions. Results indicated that the sampling system was effective with the Carboxen/Polydimethylsiloxane (CAR/PDMS) fiber in extracting all 11 standard compounds. The best sampling conditions for the extraction were a 100-mL sampling vial subjected to a continuous flow of 100 mL/min for 60 min. The gas chromatographic analysis showed that the reproducibility was within acceptable ranges for all compounds (RSD=4.24-17.26% by peak areas). In addition, field tests revealed that the sampling system was capable of detecting over 60 VOCs in a swine house whose major components were identified by gas chromatography-mass spectrometry (GC-MS) and by their retention times as volatile fatty acids, phenols, indole, and skatole. The field tests also showed that considerably different levels of VOCs were present in various parts of the swine building.  相似文献   

17.
Germs, xenobiotics and organic matter that influence the colour, turbidity and organoloeptic properties of water are removed by chlorination. Unfortunately, chlorine oxidants including sodium hypochlorite, used in water treatment induce processes that partly convert the treated compounds to unwanted chlorinated derivatives. The purpose of this work was to analyse the efficiency of transformation of phenol, catechol, guaiacol and syringol exposed to sodium hypochlorite and determine the intermediates formed during oxidative conversion of these compounds. The analysis was performed in aerobic conditions, both in acidic (pH 4.0) and alkaline (pH 8.0) medium. The effectiveness of transformation was slightly higher in acidic in comparison to alkaline conditions. Some chlorophenols, such as 2-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol were determined as the products of phenol conversion. Chlorophenols were also formed during catechol, guaiacol and syringol transformation by replacement of hydroxy and methoxy residues by chlorine atoms. Moreover, some chlorocatechols and chlorinated methoxyphenols were determined during catechol and methoxyphenols transformations. Higher concentrations of chlorinated compounds were observed in the alkaline environment during phenol transformation. Conversion of catechol and methoxyphenols generated higher amounts of chlorinated intermediates in the acidic medium. In samples carboxylic acids like acetic and formic acids were determined. The formation of these compounds was the result of the cleavage of aromatic structure of phenols.  相似文献   

18.
A solid-phase microextraction (SPME) procedure has been developed to extract eight organophosphorus pesticides (OPs) in water and the method was compared with a conventional solid phase extraction (SPE) technique. The extracted OPs were analyzed by gas chromatography using thermionic specific detection. Both extraction methods presented linear calibration at least over the concentration range investigated (100 to 1000 ng x mL(-1) for SPE and 1 to 100 ng x mL(-1) for SPME). SPME method presented higher sensitivity than SPE. The quantitation limits were between 0.1 to 1.0 ng x mL(-1) for SPME depending upon the analyte, and 100 ng x mL(-1) for SPE. The precision, as measured by the standard deviations (RSD), were in the range 3.6% to 5.8% for SPME and 2.4% to 9.2% for SPE. Along with the feature of being a solvent - free sampling technique, SPME offers additional benefits due to its high sensitivity, simplicity, and small size sample required (typically: SPE - 500 mL, SPME - 5 mL).  相似文献   

19.
The sonochemical degradation of aqueous solutions containing low concentrations of six phthalate esters at an ultrasonic frequency of 80 kHz has been investigated. Ultrasonic treatment was found capable of removing the four higher molecular mass phthalates (di-n-butyl phthalate, butylbenzyl phthalate, di-(2-ethylhexyl) phthalate and di-n-octyl phthalate) within 30-60 min of irradiation. The rest (dimethyl phthalate and diethyl phthalate) were more recalcitrant and nearly complete removal could be achieved only after prolonged irradiation times. The relative reactivity of phthalates was explained in terms of their hydrophobicity. Experiments were carried out at an overall initial phthalate concentration of 240 microg l(-1), values of electric power of 75 and 150 W, temperatures of 21 and 50 degrees C and in the presence of NaCl to study the effect of various operating conditions on degradation. Solid-phase microextraction (SPME) coupled with GC-MS proved to be a powerful analytical tool to monitor the sonochemical degradation of phthalate esters at low microg l(-1) concentration levels, minimising the risk of secondary contamination during sample preparation, a major parameter to consider during phthalates analysis. The advantages as well as disadvantages of using SPME are also highlighted.  相似文献   

20.
From 1995 to 1998 the concentrations of 4-nitrophenol, 2-methyl-4-nitrophenol, 3-methyl-4-nitrophenol, dinitro-ortho-cresol (DNOC) and 2,4-di-nitrophenol were measured monthly by HPLC in precipitation at eight different locations in Bavaria (Germany). Samples were collected by purpose-constructed computerised rainwater samplers which record electronically various sensor data each hour and adjust the sample temperature to 4 degrees C. The highest nitrophenol (NP) concentrations were measured for 4-NP. The median at all locations is higher than 1 microg/l. The median of the other NPs ranges between 0.2 and 0.8 microg/l. Considering the rain amounts the highest depositions were calculated for the regions Spessart, Bayerischer Wald and Chiemgauer Alpen. The median of 4-NP depositions extents to 200 microg/(month m2). The highest medians of the other NP depositions reach approximately 50 microg/(month m2).  相似文献   

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