Input/output balance of estrogenic active compounds in a major municipal sewage plant in Germany

24 h samples of untreated and treated wastewater were taken in parallel from a modern municipal sewage plant in southern Germany in March and June 1998. After solid phase extraction, total estrogenic activity was quantitatively measured with a miniaturized E-screen assay and the levels of nine estrogenic phenolic chemicals analyzed by HRGC/LRMS. 17Beta-estradiol equivalent concentrations (EEQ) were 58 and 70 ng/l in the influent and 6 ng/l in the effluent, indicating that the load of estrogenic activity of the wastewater was reduced by about 90% in the sewage plant. Less than 3% of the estrogenic activity was found in the sludge. 4-t-octylphenol, 4-nonylphenol, bisphenol A, 2-hydroxybiphenyl, and 4-chloro-3-methylphenol were detected in the untreated wastewater at levels from 0.13 to 3.6 microg/l. 4-t-octylphenol, 4-nonylphenol, and bisphenol A were present in the effluent at concentrations from 0.16 to 0.36 microg/l, 2-hydroxybiphenyl and 4-chloro-3-methylphenol were not detectable. The contribution of the quantified levels of phenolic xenoestrogens to total estrogenic activity in the sewage was 0.7-4.3%.     

Phenolic xenoestrogens in surface water, sediments, and sewage sludge from Baden-Württemberg, south-west Germany.

Nine structurally different phenolic chemicals, which have been reported to mimic estrogen effects, were determined in various aquatic environmental compartments. Twenty-three water samples from five streams and rivers showed levels up to 458 ng/l for 4-nonylphenol (4NP), 189 ng/l for 4-t-octylphenol (4tOP), 272 ng/l for bisphenol A (BPA) and 47 ng/l for 2-hydroxybiphenyl (2OHBiP). Elevated levels of these compounds in a stream with a high load of effluents of sewage treatment plants (STPs), compared to a brook free of sewage, identified STPs as major sources. With a similar order, 4NP (10-259 micrograms/kg dry matter), 4tOP (< 0.5-8 micrograms/kg), BPA (< 0.5-15 micrograms/kg), and 2OHBiP (2-69 micrograms/kg) were also detected regularly in riverine sediment (n = 11). Levels in sewage sludge were one order of magnitude higher than in sediments. 4-Hydroxybiphenyl and 4-chloro-3-methylphenol were found predominantly in sludge and sediment in the lower ppb range.     

Application of GC-MS/MS for the analysis of PCDD/Fs in sewage effluents

The application of high resolution gas chromatography in combination with tandem mass spectrometry in an ion trap was tested to substitute the expensive high resolution mass spectrometry in analysing polychlorinated dibenzo-p-dioxins and furans in sewage effluents. In tandem mass spectrometry, a set of parameters has to be optimised in order to attain the required sensitivity. To the best of our knowledge, this is the first time a method development for analysing PCDD/Fs with GC-MS/MS in an ion trap is described in this detail. Nine parameters are varied, including isolation window, collision induced dissociation (CID) amplitude, CID time, acquisition mass range, broadband amplitude, CID bandwidth, modulation range, filament current and ion trap temperature. This technique can be adapted to other analytes. By this optimisation, limits of detection of 0.01-0.05 ng/l are obtained. With its selectivity and sensitivity, tandem mass spectrometry is a powerful tool for the determination of PCDD/Fs in water samples. 55 sewage effluent samples from Germany were analysed.     

Fast determination of phenoxy acid herbicides in carrots and apples using liquid chromatography coupled triple quadrupole mass spectrometry

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.     

Determination of selected pharmaceuticals and caffeine in sewage and seawater from Tromsø/Norway with emphasis on ibuprofen and its metabolites

Selected pharmaceuticals, among them analgesics, ss-blockers and anti-depressants as well as caffeine, the anti-bacterial triclosan and the insect repellent N,N-diethyl-3-toluamide (DEET) were determined in different sewage samples (sewage treatment plants, hospital effluents) from Troms?/Norway and in seawater from Troms?-Sound, into which the sewage is discharged. While caffeine, triclosan, ibuprofen and its major metabolites hydroxy- and carboxy-ibuprofen were present in all sewage samples, additional pharmaceuticals were observed in sewage containing hospital effluents. Concentrations were in the range of 20-293 microg/l (caffeine), 0.2-2.4 microg/l (triclosan) and 0.1-20 microg/l (sum ibuprofen + metabolites). In seawater, only caffeine (7-87 ng/l), DEET (0.4-13 ng/l) and ibuprofen + metabolites (sum concentration < LOQ-7.7 ng/l) were detected. Ibuprofen and its metabolites hydroxy- and carboxy-ibuprofen were quantified individually by use of the respective reference compounds. Relative amounts of the three compounds were determined in different types of water showing characteristic patterns, with hydroxy-ibuprofen being the major component in sewage whereas carboxy-ibuprofen was dominant in seawater samples. The patterns which were compared to those observed in similar samples from Germany indicated different transformation behaviour under limnic and marine conditions.     

Photocatalytic degradation of chlorophenols in soil washing wastes containing Brij 35. Correlation between the degradation kinetics and the pollutants–micelle binding

The photocatalytic degradations of 4-chlorophenol (CP), 4-chloro-2-methylphenol (CMP), 4-chloro-3,5-dimethylphenol (CDMP) and 4-chloro-2-isopropyl-5-methylphenol (CIMP) were investigated in water and in simulated soil washing wastes containing Brij 35 (polyoxyethylene(23)dodecyl ether) in the presence of TiO₂ dispersions. A neat inhibition of substrate decomposition proportional to their growing hydrophobicity was observed in the washing wastes for CP, CMP and CDMP, whereas CIMP showed a different behaviour. The mineralization of the organic chlorine of CP and CIMP was relatively fast and complete, whereas it was much slower for CMP and CDMP. Micellar solubilization and substrate adsorption onto the semiconductor play opposite roles on the degradation kinetics, and a breakpoint between the corresponding induced effects was evidenced when the pollutants become completely bound to the micellar aggregates.     

Endocrine disruptors in freshwater streams of Hesse, Germany: changes in concentration levels in the time span from 2003 to 2005

Four small freshwater streams in the region known as Hessisches Ried in Germany were investigated with respect to the temporal and spatial concentration variations of the endocrine disruptors bisphenol A (BPA), 4-tert-octylphenol (4-tert-OP), and the technical isomer mixture of 4-nonylphenol (tech.-4-NP). Measured concentrations of the target compounds in the river water samples ranged from <20 ng/l to 1927 ng/l, <10 ng/l to 770 ng/l, and <10 ng/l to 420 ng/l for BPA, 4-tert-OP and tech.-4-NP, respectively. BPA levels were, with the exception of two samples, below the predicted no-effect concentration (PNEC) for water organisms. Tech.-4-NP concentrations showed a significant tendency of decreasing concentrations during the sampling period. This is mainly attributed to the implementation of the European Directive 2003/53/EG, which restricts both the marketing and use of nonylphenols. Results from the analysis of additionally collected water samples from sewage treatment plant (STP) effluents indicate that the STPs cannot be the only sources for tech.-4-NP found in the river water.     

Analysis of acidic pesticides using in situ derivatization with alkylchloroformate and solid-phase microextraction (SPME) for GC-MS.

A solid-phase microextraction (SPME) method was developed for the analysis of acidic pesticide residues in water. The method utilizes in situ derivatization with butylchloroformate (BuCF), followed by on-line SPME extraction using a PDMS fibre, and analysis by GC-MS. Derivatives of the phenoxy acids mechlorprop (MCPP), dichlorprop (DCPP), MCPA and 2,4-D and their phenol degradation products 4-chloro-2-methylphenol and 2,4-dichlorophenol (DCP) were identified. Detection limits at 0.16-2.3 microg/l were achieved. Optimization of derivatization, ion strength, extraction time, SPME-fibre, desorption time and temperature are described. Standard curves in the range 0.5-10.0 microg/l were fitted to a second-degree polynomial. Standard deviation (n = 5) was below 10% for the phenol derivatives, but 20-50% for the phenoxy acids. For method verification groundwater samples from a field experiment were screened for content of MCPP and compared to the results from the HPLC analysis. A good agreement was obtained with respect to identification of positive samples, even though concentrations measured by the SPME were lower than with HPLC. Even if the precision and accuracy do not meet the demands for a strictly quantitative analysis, the SPME method is suitable for screening, because it is cheap, it can be automated, and uses smaller amounts of potential harmful solvents. Also, the method is less labour-intensive, as it requires a minimum of sample preparation when compared to traditional analyses. The acidic pesticides bentazon, dicamba, bromoxynil, ioxynil, dinoseb and DNOC were included in the study but could not be analysed by the current method.     

Photodegradation of chlorinated pesticides dispersed on sand

The photochemical behaviour of several chlorinated pesticides, namely 4-chloro-2-methylphenoxyacetic acid (MCPA), dichlorophen (DCPH), flamprop-methyl (FPM) and vinclozolin (VCZ) is studied on various kinds of sand: Fontainebleau sand (almost pure silica), Touggourt sand (coloured sand from Sahara) and Jijel sand (dark marine sand). The photodegradation of MCPA is more rapid on Fontainebleau sand than on the two others, because the former is almost colourless pure silica and the others adsorb on the internal surface of the reactor. The degradation rate decreases in the order MCPA, DCPH, FPM, VCZ. The main products identified are 4-chloro-2-methylphenol with MCPA and reduction product with DCPH.     

Distribution and incorporation mode of the herbicide MCPA in soil derived organo-clay complexes

The incorporation of xenobiotics into soil, especially via covalent bonds or sequestration has a major influence on the environmental behavior including toxicity, mobility, and bioavailability. The incorporation mode of 4-chloro-2-methylphenoxyacetic acid (MCPA) into organo-clay complexes has been investigated under a low (8.5 mg MCPA/kg soil) and high (1000 mg MCPA/kg soil) applied concentration, during an incubation period of up to 120 days. Emphasis was laid on the elucidation of distinct covalent linkages between non-extractable MCPA residues and humic sub-fractions (humic acids, fulvic acids, and humin). The cleavage of compounds by a sequential chemical degradation procedure (OH^?, BBr₃, RuO₄, TMAH thermochemolysis) revealed for both concentration levels ester/amide bonds as the predominate incorporation modes followed by ether linkages. A possible influence of the soil microbial activity on the mode of incorporation could be observed in case of the high level samples. Structure elucidation identified MCPA as the only nonextractable substance, whereas the metabolite 4-chloro-2-methylphenol was additionally found as bioavailable and bioaccessible compound.     

Enantioselective biodegradation of mecoprop in aerobic and anaerobic microcosms

Natural attenuation of mecoprop has been studied by determining changes in enantiomeric fraction in different redox environments down gradient from a landfill in the Lincolnshire limestone. Such changes could be due to differential metabolism of the enantiomers, or enantiomeric inversion. In order to confirm the processes occurring in the field, microcosm experiments were undertaken using limestone acclimatised in different redox zones. No biodegradation was observed in the methanogenic, sulphate-reducing or iron-reducing microcosms. In the nitrate-reducing microcosm (S)-mecoprop did not degrade but (R)-mecoprop degraded with zero order kinetics at 0.65 mg l(-1)day(-1) to produce a stoichiometric equivalent amount of 4-chloro-2-methylphenol. This metabolite only degraded when the (R)-mecoprop disappeared. In aerobic conditions (S)- and (R)-mecoprop degraded with zero order kinetics at rates of 1.90 and 1.32 mg l(-1)day(-1) respectively. The addition of nitrate to dormant iron-reducing microcosms devoid of nitrate stimulated anaerobic degradation of (R)-mecoprop after a lag period of about 20 days and was associated with the production of 4-chloro-2-methylphenol. Nitrate addition to sulphate-reducing/methanogenic microcosms did not stimulate mecoprop degradation. However, the added nitrate was completely utilised in oxidising sulphide to sulphate. There was no evidence for enantiomeric inversion. The study reveals new evidence for fast enantioselective degradation of (R)-mecoprop under nitrate-reducing conditions.     

Formation of chlorinated estrones via hypochlorous disinfection of wastewater effluent containing estrone

Chlorinated derivatives of estrone (E1) in the effluent of a municipal sewage treatment plant located in Shizuoka prefecture, Japan were detected by gas chromatography/mass spectrometry using electron impact in selected ion monitoring (GC/MS-EI-SIM) analysis. The concentrations of E1, 2-chloroestrone, 4-chloroestrone and 2,4-dichloroestrone in the effluent sample collected in December 2005 were 60.0 ng l(-1), 4.0 ng l(-1), 14.5 ng l(-1), and 9.8 ng l(-1), respectively. In the effluent sample taken in June 2005, 2,4-dichloroestrone was detected at 5.6 ng l(-1) along with 17.6 ng l(-1) of E1. However, only E1 was detected at 5.9 ng l(-1) in the sample in May 2005. To elucidate the behavior of E1 during the disinfection process with sodium hypochlorite in the sewage treatment plant, we carried out a reaction of E1 with sodium hypochlorite in buffer solutions at pH 7 and 9. As E1 was consumed rapidly, chlorinated estrones were produced and relatively fast formation of 2-chloroestrone, 4-chloroestrone, and 2,4-dichloroestrone was observed. Furthermore, 1,4-estradiene-3,17-dione derivatives were formed from the reaction between 2,4-dichloroestrone and sodium hypochlorite.     

Atmospheric deposition of organochlorines (PCBs and pesticides) in northern France

Bulk deposition measurements were made in northern France for a number of organochlorines (PCBs, HCB, pp'DDE, alpha-HCH and gamma-HCH) over a 1-y period, at urban, semi-rural, rural and forest sites located in accordance with prevailing wind direction. The west-east rise of PCB bulk deposition (average annual values as sigma 7) ranged from 12.2 to 46.8 ng l(-1) and showed the anthropogenic influence arising from towns, industries, storage areas and landfills over continental areas. The values were maximal at the urban site 3, Paris (122 ng l(-1)) and were still high at the eastern site 6, Abreschviller near landfills (62 ng l(-1)). Also, the highest annual deposits were found at sites 3 and 6 (Paris and Abreschviller), 38.6 and 47.3 microgm-2, respectively, i.e. 3.6 and 4 times higher than the western site value: Pleumeur. A temporal trend was observed, at the urban site where a rise occurred (up to 441 ng l(-1)) in March and April. PCB distribution according to the chlorination degree displayed high proportions of 3 Cl and 4 Cl congeners, particularly in the forest area. Annual gamma-hexachlorocyclohexane (gamma-HCH) concentration values at sites 1 (Ouessant) and 2 (Pleumeur) were close to the background noise (1.7 ng l(-1)). At the agricultural (4) and the urban (3) sites, values were maximal (19.2 and 15.9 ng l(-1)) with peaks in spring and autumn. At Pleumeur, without any local input, negative correlations were found between PCB/temperature (r = -0.503, p < 0.05), HCB/temperature ( r = -0.549, p < 0.01) and gamma-HCH/temperature ( r = -0.675, p < 0.01). A clear influence of south-west winds upon the magnitude of PCB fluxes throughout the sites was noticed. Whereas there was no global decrease of PCB contamination since 1986, the general trend of gamma-HCH total deposits was a 10-time fall, as a result of the restricting legislation in use.     

Simultaneous determination of chlorothalonil and its metabolite 4-hydroxychlorothalonil in greenhouse air: dissipation process of chlorothalonil

An analytical method was developed and tested for the simultaneous determination of chlorothalonil and its main metabolite 4-hydroxychlorothalonil, in airborne samples. High performance liquid chromatography equipped with Ultra-violet detector was used to separate and quantify the analytes. Glass microfibre filters for the collection of the analytes' particles were tested. Solid sorbents, such as Tenax, Florisil, XAD-2 and silica gel, were studied to find out the most suitable material for the collection of the analytes in the gas phase. The results have shown that only chlorothalonil was trapped in the vapor phase with highest results obtained when silica gel was the sorbent of choice. Linearity was demonstrated in a wide concentration range 0.01-10.00 mg L(-1). Recoveries from spiked glass microfibre filters and silica gel cartridges for chlorothalonil and 4-hydroxychlorothalonil were almost quantitative. The quantification limits were calculated to be 8.4 and 19.6 ng m(-3) in air for chlorothalonil and 4-hydroxychlorothalonil, respectively. The two analytes spiked on the GF/A filters and silica gel cartridges were proven to be stable for more than 15 days, at 4degrees C and ambient temperature. The applicability of the present method was demonstrated by the analysis of the chlorothalonil and its metabolite in greenhouse air.     

A simple spectrophotometric method for the determination of cobalt in industrial, environmental, biological and soil samples using bis(salicylaldehyde)orthophenylenediamine

Bis(salicylaldehyde)orthophenylenediamine (BSOPD) has been proposed as new analytical reagent for the direct non-extractive spectrophotometric determination of cobalt. It reacts with cobalt in slightly acidic (0.0002-0.001 M H(2)SO(4)) 50% 1,4-dioxanic medium to form a red-orange chelate with a molar ratio 1:1. The reaction is instantaneous and the maximum absorbance was obtained at 458 nm and remains constant for over 24h. The average molar absorption coefficient and Sandell's sensitivity were found to be 1.109 x 10(4)l mol(-1)cm(-1) and 20 ng cm(-2) of Co(II), respectively. Linear calibration graph was obtained for 0.1-15 mg l(-1) of Co(II) with a correlation coefficient value of 0.995 for Co-BSOPD complex. Large excess of 44 cations, anions and complexing agents do not interfere in the determination. The method was successfully used in the determination of cobalt(II) from synthetic mixture and certified reference materials for the purpose of validating the method and the results of analyses were found to be excellent agreement with those of actual values. This developed method was also used for determination of cobalt in some environmental waters (potable and polluted), biological (blood and urine) and soil samples and solution containing both cobalt(II) and cobalt(III). The results of the proposed method for biological samples were comparable with AAS and were found to be in good agreement. The method has high precision and accuracy (s=+/-0.01 for 0.5 mg l(-1)).     

Considerations about the enantioselective transformation of polycyclic musks in wastewater, treated wastewater and sewage sludge and analysis of their fate in a sequencing batch reactor plant

The present work consists of two distinct parts: in the first part enantioselective GC was used to separate the different enantiomeric/diastereomeric polycyclic musks, PCMs (HHCB, AHTN, AHDI, ATII and DPMI) including the main transformation product of HHCB, HHCB-lactone, in wastewater and sewage sludge. After optimization all PCMs were resolved on a cyclodextrin containing Rt-BDEXcst capillary GC column. Enantiomeric ratios of PCMs in a technical mixture were determined and compared to those obtained from enantioselective separation of wastewater and sewage sludge samples. In general, enantiomeric ratios were similar for most materials in influent, effluent and stabilized sewage sludge. However, the ratios for HHCB, AHDI and particularly ATII suggest some stereospecific removal of these compounds. In the second part, a field study was conducted on a wastewater treatment plant comprising a sequencing batch reactor. Concentrations of HHCB, AHTN, ADBI, AHDI, ATII, DPMI and HHCB-lactone were determined by non-enantioselective GC in daily samples of influent, effluent and activated sludge during one week. Mean concentrations in influent were 6900 and 1520 ng/l for HHCB and AHTN, respectively. The other PCMs exhibited contents 200 ng/l. Mean percent removal was between 61% (AHDI) and 87% (HHCB) resulting in mean effluent concentrations below 860 ng/l. HHCB-lactone concentration increased during wastewater treatment with a mean in the influent of 430 ng/l and in the effluent of 900 ng/l, respectively, indicating a degradation of HHCB.     

Analysis of some organochlorine pesticides in an urban atmosphere (Strasbourg, east of France)

High volume samples of urban air have been collected in Strasbourg, a big city situated in the east of France, for the evaluation of the contamination by organochlorine pesticides. Pesticides (p,p'-DDT, p,p'-DDD, p,p'-DDE, aldrin, dieldrin, endrin, gamma-HCH, cis-chlordane, trans-chlordane, alpha-endosulfan, beta-endosulfan, hexachlorobenzene, heptachlor and some of their metabolites: alpha-HCH, 2,4'-DDT, 2,4'-DDD and 2,4'-DDE) were analysed by GC-ECD. Prior to analysis, samples were Soxhlet extracted with a mixture of n-hexane/methylene chloride. The analysis of samples collected in 2001 (n = 6), 2002 (n = 7) and 2003 (n = 5) shows that alpha-HCH and gamma-HCH were detected in all samples (between 0.05 and 4 ng m(-3) and between 0.01 and 1 ng m(-3), respectively) along with aldrin and dieldrin at lower concentrations (between 0.01 and 0.08 ng m(-3) and between 0.02 and 0.09 ng m(-3), respectively). Other pesticides were detected very randomly at very low concentrations. The calculation of the alpha/gamma-HCH ratio shows that hexachlorocyclohexane measured in the atmosphere have a local origin and come probably from contaminated soil by volatilisation. alpha and beta-endosulfan were practically not detected in samples collected in 2001 and 2002 while they were always measured in the gas phase in samples from 2003. This observation can be explained by an increase of volatilisation with the increase of the air temperature. In July, temperature were higher (between 17 and 30 degrees C in climatic station) than in March-May 2001 and 2002 (between 2 and 19 and between 2 and 10, respectively).     

Estimation of dioxin emission from fires in chemicals

The formation of the 17 toxic 2,3,7,8-substituted PCDDs and PCDFs during combustion of selected chemicals were measured by high-resolution GC/MS. The 16 chemicals studied were commonly used chlorinated pesticides, industrial chemicals, and PVC. In a series of experiments carried out in a DIN 53,436 furnace, 2.5 g of these compounds were burned at 500 degrees C and 900 degrees C, respectively. The resultant yields ranged from 740 ng ITEQ/g for pentachlorophenol, to below 0.01 ng ITEQ/g for PVC and dichlobenil. The results show that some chemicals generate PCDD/F in very high--possibly dangerous--amounts during burning, whereas others generate insignificant amounts. The influence of scale were studied for chlorobenzene and 4-chloro-3-nitro-benzoic acid in additional experiments, carried out in a cone calorimeter burning 20 g substance, and in ISO 9705 room test burning about 50 kg. A good agreement between the results for large and small scale indicated that formation of PCCD/F during a fire may be estimated from laboratory experiments. This suggest laboratory test may be used to screen for chemicals posing a hazard for release of PCDD/F during fires.     

Comparing solid phase extraction and direct injection for the analysis of ultra-trace levels of relevant explosives in lake water and tributaries using liquid chromatography-electrospray tandem mass spectrometry

Off-line solid phase extraction and direct injection analysis were evaluated for the determination of traces of explosives such as TNT and its mono and diamino metabolites, HMX, RDX, nitroglycerin and PETN in lake water and tributaries applying liquid chromatography-electrospray tandem mass spectrometry. Improved chromatographic separation was achieved on a phenyl based stationary phase with baseline resolution of the mono- and diamino metabolites of TNT. Identification and quantification of the target compounds was performed by multiple reaction monitoring applying electrospray ionization in either the positive mode for the diaminometabolites of TNT or the negative mode for all other compounds. An extensive method validation was performed and limits of quantification were obtained for the explosives in preconcentrated lake water samples from 0.03 to 1 ng l(-1) and 0.1 to 5 ng l(-1) in river water. Direct injection analysis revealed comparable results to preconcentrated water samples for the most persistent explosives. Analysis of lake water samples collected at different depths showed the presence of HMX, RDX and PETN at concentrations from 0.1 to 0.4 ng l(-1). The analysis of main tributaries revealed concentrations from 0.1 to 0.9 ng l(-1) of the same compounds. They seem to be responsible for the contamination of the explosives in the lakes.     

Solid phase extraction with pyrenebutyric acid-bonded silica for analysis of polychlorinated biphenyls in sewage water by gas chromatography-mass spectrometry

A solid phase extraction (SPE) method using pyrenebutyric acid-bonded silica (PYB) as sorbent was developed to determine 23 polychlorinated biphenyls (PCBs) in sewage water by gas chromatography-mass spectrometry (GC-MS). Factors were optimized in SPE procedures including elution solvent, pH, and cartridge burden. The recoveries of 23 PCB congeners were 69.44-111.91% under optimized conditions. Comparisons were also conducted among PYB-SPE, C(18)-SPE and United States Environmental Protection Agency 608 (USEPA608) methods in the analysis of PCBs in sewage water samples. The results showed that the performance of PYB-SPE method was similar with USEPA608 method and better than C(18)-SPE method. Both PYB-SPE and USEPA608 methods were then employed to analyze PCBs in real spiked sewage water samples. The recoveries of PCB congeners determined by PYB-SPE method ranged from 70.6% to 92.4% in real spiked sewage water samples which were identified to be in accordance with USEPA608 method. Limits of detection (LOD) were in the range of 0.06-0.22ngL(-1) for PCB congeners. The optimized PYB-SPE method was successfully applied to the determination of PCBs in sewage water samples.