Occurrence and removal of estrogenic short-chain ethoxy nonylphenolic compounds and their halogenated derivatives during drinking water production

The elimination of nonylphenol (NP), nonylphenol mono- and diethoxylates (NP1EO and NP2EO), nonylphenol carboxylates (NP1EC and NP2EC) and their brominated and chlorinated derivatives during drinking water treatment process in Sant Joan Despf waterworks in Barcelona was investigated utilizing a recently developed, highly sensitive LC-MS-MS method. The concentration of these potentially estrogenic compounds in raw water entering waterworks (taken from the Llobregat River, NE Spain) ranged from 8.3 to 22 microg/L, with NP2EC being the most abundant compound. Prechlorination reduced the concentration of short-chain ethoxy NPECs and NPEOs by about 25-35% and of NP by almost 90%. However, this reduction of concentrations was partially due to their transformation to halogenated derivatives. After prechlorination, halogenated nonylphenolic compounds represented approximately 13% of the total metabolite pool, of which 97% were in the form of brominated acidic metabolites. The efficiency of further treatment steps to eliminate nonylphenolic compounds (calculated for the sum of all short-chain ethoxy metabolites including halogenated derivatives) was as follows: settling and flocculation followed by rapid sand filtration (7%), ozonation (87%), GAC filtration (73%), and final disinfection with chlorine (43%), resulting in overall elimination ranging from 96 to 99% (mean 98% for four sampling dates). A few of the nonylphenolic compounds (NP, NP1EC, and NP2EC) were also identified in drinking water; however, the residues detected were generally below 100 ng/L, with one exception for NP2EC in November 2001 when a concentration of 215 ng/L was detected.     

Relationship between solid retention time and phosphorus removal in anaerobic-intermittent aeration process

Solid retention time (SRT) is one of the most important control parameters in biological phosphorus removal. In this study, lab-scale biological nutrient removal (BNR) reactors using anaerobic-intermittent aeration (AIA) were operated at various SRTs (i.e., 15, 20, and 30 d) to evaluate their phosphorus removal efficiencies. Sludge wasting load decreased as SRT increased; however, the phosphorus content in the biomass increased as SRT increased. The highest phosphorus removal efficiency was 93% at an SRT of 20 d and the phosphorus wasting load was also highest at that SRT, which indicates that the optimal SRT for the highest phosphorus removal is not proportional to the phosphorus content in the biomass. Aerobic digestion experiments were also carried out to determine the number of phosphate-accumulating organisms (PAOs) in the biomass produced in different reactors. All three activated sludges from BNR at SRTs of 15, 20, and 30 d showed a slower volatile suspended solid (VSS) destruction rate and a larger amount of phosphorus released than the conventional activated sludge (CAS), suggesting that the activated sludge from BNR has more PAOs than CAS. Also, the sludge at an SRT of 30 d showed a slower VSS destruction rate and a larger amount of phosphorus released than the sludge at an SRT of 15 d, suggesting that PAOs are more predominant at longer SRTs. Thus, to improve phosphorus removal efficiency, it is recommended that SRT be increased to maximize the number of PAOs in the system and that SRT be determined to maximize phosphorus wasting load.     

Fate of estrogens during the biological treatment of synthetic wastewater in a nitrite-accumulating sequencing batch reactor

The fate of estrone (El), 17beta-estradiol (E2), and 17alpha-ethynylestradiol (EE2) was investigated in two nitrite-accumulating sequencing batch reactors operating under strictly aerobic (SBR1) conditions at different sludge ages (SRT, 1.7 to 17.1 d) and anoxic/anaerobic/aerobic (SBR2) conditions with different phases and durations of redox conditions, using a modified GC-MS analytical method for estrogen detection to ng/L concentrations. In SBR1, > or =98% of E2 was removed (specific E2 removal rate ranged from 0.375 (at SRT 17.1 d) to 2.625 (at SRT 1.7 d) microg E2 x g MLVSS(-1) x d(-1)) regardless of SRT or DO (<1.0 to >5.0 mg/L). Removal of E1 and, to a greater extent, EE2 was adversely affected when this reactor was operated at SRT shorterthan 5.7 d. However, whereas E1 was removed efficiently as long as SRT was long enough for AOB to bring about nitritation, EE2 removal efficiency was significantly lower when SBR1 was operated at SRT longer than 7.5 d. This reduced removal of EE2 may have been caused by the inhibition and toxicity of nitrite, both to the ammonium monooxygenase (AMO) and to the microbial population generally. In SBR2, less removal of E2 was found at the lower MLVSS concentrations, and E1 was not removed by sludge with poor settling qualities. The removal of EE2 observed in SBR2 was considered to be mainly a result of sorption. However, the binding of estrogens to the sludge in this reactor was apparently not as strong as the binding observed in the sludge of the strictly aerobic SBR1, since desorption was observed during the aeration phase in SBR2.     

Distribution and behavior of nonylphenol, octylphenol, and nonylphenol monoethoxylate in Tokyo metropolitan area: their association with aquatic particles and sedimentary distributions

Distributions of alkylphenols (APs) [i.e., nonylphenol (NP), octylphenol (OP)], and nonylphenol monoethoxylate (NP1EO) in wastewater effluents, river water, and riverine and bay sediments in the Tokyo metropolitan area were demonstrated. During sewage treatments, NP and OP were efficiently removed from the sewage effluents through activated sludge treatments. Greater removal for NP (93% on average) than OP (84% on average) was consistent with their partitioning behavior to particles in primary and secondary effluents. NP concentrations in the river water samples ranged from 0.051 to 1.08 microg/L with higher concentrations in summer and spring than in colder seasons. In the river water samples, approximately 20% of NP was found in the particulate phase. Organic carbon-normalized apparent partition coefficients (K'OC) for NP (10(5.22 +/- 0.38)) and OP (10(4.65 +/- 0.42)) were 1 order of magnitude higher than those expected from their octanol-water partition coefficients (K(OW)), indicating strong affinity of APs to aquatic particles. Among NP isomers, no significant differences in their K'OC values were suggested. This is consistent with surprisingly uniform isomer peak profiles among the technical standard and all the environmental samples analyzed. NP and OP were widely distributed in the river sediments in Tokyo, and relatively high concentrations (0.5-13.0 microg/g dry) of NP were observed in a long reach (approximately 10 km) in the Sumidagawa River. In situ production of APs in the river sediment was suggested. Seaward decreasing trend in APs concentration was observed from the estuary to the Tokyo Bay. APs were well preserved in a sediment core collected from the bay. The profile shows subsurface maximum of AP concentrations in the layer deposited around the mid-1970s. The recent decrease in AP concentrations can be attributed to the legal regulation of industrial wastewater in the early 1970s.     

Alkylphenol and alkylphenol-ethoxylates in carp,water, and sediment from the Cuyahoga River,Ohio

The occurrence of alkylphenol and alkylphenol ethoxylates (APEs) was determined over a 74-mile length of the Cuyahoga River, Ohio. Measurable levels of both the octyl and nonyl forms of these abundantly used nonionic surfactants were observed with the nonylphenol (NP) plus nonylphenol ethoxylates (NPEs) typically accounting for greater than 90% of the total APEs in each sample. For all media (water, fish, and sediment) the total NPE (NP + NPE) concentrations were higher in the more urbanized downstream section of the river. Maximum water and fish values were observed immediately downstream (2.1 miles) from the discharge of the Akron WWTP located 35.31 miles from the river mouth and the sediment maxima occurred at the most downstream site near Cleveland. The ranges in concentration fortotal NPEs and their ethoxylate (EO) makeup were as follows: 32-920 ug/kg wet wt (NP 0 to 2 EO) for carp; 0.13-1.0 ug/L (NP 0 to 3 EO) for water; and 250-1020 ug/kg dry wt (NP 0 to 5 EO) for sediment. When the higher ethoxymers (NP 6 to 17 EO) were added to these sediment totals, the average total estimated NPE concentrations were 1.3-1.8 times higher.     

Biogeochemistry of nonylphenol ethoxylates in urban estuarine sediments

We have examined the concentrations and distributions of nonylphenol ethoxylate (NPEO) surfactants and their primary neutral metabolites in two dated sediment cores collected in 1988 and 1996 from a depositional area proximal to a wastewater treatment plant within Jamaica Bay, NY. Total NPEO concentrations ranged from >50 microg/g near the surface (4-6 cm, deposited ca. 1990) to below detection limits (<0.1 microg/g) at 50 cm depth (deposited ca. 1940). The general decrease in NPEO concentrations with increasing depth in sediment reflected increased commercial use of these compounds over the last 50 yr. NPEO ethoxymer distributions in recent sediments were dominated by NP(0-3)EO, consistent with the increased relative input of these particular ethoxymers to the estuary following the upgrade of local biological sewage treatment processes to full activated sludge in the late 1970s. NPEO ethoxymer profiles in deeper sediments were characterized by relatively higher proportions of unmetabolized, highly ethoxylated NPEOs. Depth profiles of NP1EO and NP in the upper portion of the sediment core showed evidence for in situ diagenetic conversion of NP1EO to NP. However, comparison of NPEO concentrations in selected strata from the core collected in 1996 with those in matched strata from a core collected from the same location in 1988 provided no evidence for in situ degradation of total NPEOs during the elapsed 8 yr between collection dates.     

Steroid estrogens, nonylphenol ethoxylate metabolites, and other wastewater contaminants in groundwater affected by a residential septic system on Cape Cod, MA

Septic systems serve approximately 25% of U.S. households and may be an important source of estrogenic and other organic wastewater contaminants (OWC) to groundwater. We monitored several estrogenic OWC, including nonylphenol (NP), nonylphenol mono- and diethoxycarboxylates (NP1EC and NP2EC), the steroid hormones 17beta-estradiol (E2), estrone (E1) and their glucuronide and sulfate conjugates, and other OWC such as methylene blue active substances (MBAS), caffeine and its degradation product paraxanthine, and two fluorescent whitening agents in a residential septic system and in downgradient groundwater. E1 and E2 were present predominantly as free estrogens in groundwater, and near-source groundwater concentrations of all OWC were highest in the suboxic to anoxic portion of the wastewater plume, where concentrations of most OWC were similar to those observed in the septic tank on the same day. NP and NP2EC were up to 6- to 30-fold higher, and caffeine and paraxanthine were each 60-fold lower than septic tank concentrations, suggesting net production and removal, respectively, of these constituents. At the most shallow, oxic depth, concentrations of all OWC except for NP2EC were substantially lower than in the tank and in deeper wells. Yet boron, specific conductance, and the sum of nitrate-and ammonia-nitrogen were highest at this shallow depth, suggesting preferential losses of OWC along the more oxic flow lines. As far as 6.0 m downgradient, concentrations of many OWC were within a factor of 2 of near-source concentrations. The results suggest that there is the potential for migration of these OWC, which are unregulated and not routinely monitored, in groundwater.     

Elimination of selected acidic pharmaceuticals from municipal wastewater by an activated sludge system and membrane bioreactors

The elimination of six acidic pharmaceuticals (clofibric acid, diclofenac, ibuprofen, ketoprofen, mefenamic acid, and naproxen) in a real wastewater treatment plant (WWTP) using an activated sludge system and membrane bioreactors (MBRs) was investigated by using a gas chromatography/mass spectrometry (GC/MS) system for measurement of the compounds. Limited information is available for some of the tested pharmaceuticals at present. Solid retention times (SRTs) of the WWTP and the two MBRs were 7, 15, and 65 days, respectively. The elimination rates varied from compound to compound. The MBRs exhibited greater elimination rates for the examined pharmaceuticals than did the real plant. Dependency of the elimination rates of the pharmaceuticals on SRTs was obvious; the MBR operated with a longer SRT of 65 days clearly showed better performance than did the MBR with a shorter SRT of 15 days. The difference between the two MBRs was particularly significant in terms of elimination of ketoprofen and diclofenac. Measurements of the amounts of adsorbed pharmaceuticals on the sludge and aerobic batch elimination experiments were carried out to investigate the elimination pathways of the pharmaceuticals. Results of the batch elimination tests revealed that the sludges in the MBRs had large specific sorption capacities mainly due to their large specific surface areas. Despite the sorption capacities of sludges, the main mechanism of elimination of the pharmaceuticals in the investigated processes was found to be biodegradation. Biodegradation of diclofenac, which has been believed to be refractory to biodegradation, seemed to occur very slowly.     

Fate of a 14C-labeled nonylphenol isomer in a laboratory-scale membrane bioreactor

This study aimed at giving a better insight into the possible fate of nonylphenol (NP) during wastewater treatment by using a lab-scale membrane bioreactor (MBR) designed and optimized for fate studies carried out with radiolabeled compounds. After a single pulse of 14C-labeled-NP isomer (4-[1-ethyl-1,3-dimethylpentyl]phenol) as radiotracer, the applied radioactivity was monitored in the MBR system over 34 days. The mass balance of NP residues at the end of the study showed that 42% of the applied radioactivity was recovered in the effluent as degradation products of NP, 21% was removed with the daily excess sludge from the MBR, and 34% was recovered as adsorbed in the component parts of the MBR. A high amount of NP was associated to the sludge during the test period, while degradation compounds were mainly found in the effluent. Partial identification of these metabolites by means of HPLC-tandem mass spectrometry coupled to radio-detection showed they are alkyl-chain oxidation products of NP. The use of this MBR and a radiolabeled test compound was found suitable for demonstrating that under the applied conditions, the elimination of NP through mineralization and volatilization processes (both less than 1%) was negligible. However, the removal of NP via sorption and the continuous release of oxidation products of NP in permeate were of relevance.     

Removal of antibiotics in wastewater: Effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process

A study was conducted to examine the influence of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of tetracycline in the activated sludge processes. Two lab-scale sequencing batch reactors (SBRs) were operated to simulate the activated sludge process. One SBR was spiked with 250 microg/L tetracycline, while the other SBR was evaluated at tetracycline concentrations found in the influent of the wastewater treatment plant (WWTP) where the activated sludge was obtained. The concentrations of tetracyclines in the influent of the WWTP ranged from 0.1 to 0.6 microg/L. Three different operating conditions were applied during the study (phase 1-HRT: 24 h and SRT: 10 days; phase 2-HRT: 7.4 h and SRT: 10 days; and phase 3-HRT: 7.4 h and SRT: 3 days). The removal efficiency of tetracycline in phase 3 (78.4 +/- 7.1%) was significantly lower than that observed in phase 1 (86.4 +/- 8.7%) and phase 2 (85.1 +/- 5.4%) at the 95% confidence level. The reduction of SRT in phase 3 while maintaining a constant HRT decreased tetracycline removal efficiency. Sorption kinetics reached equilibrium within 24 h. Batch equilibrium experiments yielded an adsorption coefficient (Kads) of 8400 +/- 500 mL/g and a desorption coefficient (Kdes) of 22 600 +/- 2200 mL/g. No evidence of biodegradation for tetracycline was observed during the biodegradability test, and sorption was found to be the principal removal mechanism of tetracycline in activated sludge.     

Fate of octyl- and nonylphenol ethoxylates and some carboxylated derivatives in three american wastewater treatment plants

The fate of a comprehensive group of nonylphenol and octylphenol ethoxylates (APEOs) and several of their carboxylated derivatives was studied in three American wastewatertreatment plants (WWTPs), two of which included advanced treatment. Influent and effluent concentrations of the alkylphenolic compounds (APEs) in the three plants were very similar, but effluent concentrations showed a seasonal dependency: both carboxylate and ethoxylate concentrations in the effluents were higher in winter than in summer. Sorption to particulate matter was higher for nonylphenolic compounds than for their octylphenolic counterparts, in agreement with their difference in Kow values. Both effluent concentrations and the removal efficiency of the APEOs were strongly correlated to water temperature, but no correlation was found with suspended solids or organic carbon removal. Although APEO removal from wastewater was high, overall removal from the WWTPs, including APEOs in waste sludge and transformation products, was relatively low and suggested that advanced treatment does not invariably result in better APEO removal. Additionally, a survey of urban sewers suggested that household products still constitute an important source of the APEOs reaching WWTPs.     

Retrospective monitoring of alkylphenols and alkylphenol monoethoxylates in aquatic biota from 1985 to 2001: results from the German Environmental Specimen Bank

Breams (Abramis brama) and zebra mussels (Dreissena polymorpha) from freshwater, and common mussels (Mytilus edulis) from marine ecosystems, archived in the German Environmental Specimen Bankwere analyzed for the presence of 4-nonylphenol (NP), 4-tert-octylphenol (OP), nonylphenol monoethoxylate (NP1EO), and octylphenol monoethoxylate (OP1EO). The samples were collected in the German rivers Elbe, Rhine, and Saar, and in Lake Belau between 1992 and 2001, as well as in the North Sea and Baltic Sea between 1985 and 2001. The main purpose of the study was to investigate the effectiveness of imposed reduction measures regarding the use of alkylphenol ethoxylates. NP1EO and OP were detected in all breams. NP was predominantly above the limit of quantification (LOQ, 2 ng/g; all data on a wet weight basis), and OP1EO was mostly below the LOQ (0.2 ng/g). Maximal concentrations of 112 ng/g NP, 259 ng/g NP1EO, 5.5 ng/g OP, and 2.6 ng/g OP1EO were found in Saar breams from 1994. NP was detected in all zebra mussels from the river Elbe (up to 41 ng/g), whereas in rather few samples OP and NP1EO were found at low levels. OP1EO was not detected in any sample. Concentrations in mussels and breams from the reference site Lake Belau were below the LOQ for all compounds. In marine biota NP was found until 1997 with maximum concentrations up to 9.7 ng/g, whereas NP1EO was detected at levels between 1.7 and 12.9 ng/g in very few samples collected at the end of the 1980s. A tendency of the concentrations to decrease was obvious for all sampling sites; it was most pronounced for NP1EO and NP after 1996/1997. The effectiveness of the reduction measures is most evident at the Saar sampling site Güdingen and the North Sea sampling site Eckwarderh?rne.     

Fate of endocrine disrupting compounds in membrane bioreactor systems

Yeast estrogen screen (YES) bioassay and liquid chromatography-mass spectrum-mass spectrum (LC-MS-MS) analysis were performed to investigate the fate of active and potential endocrine disrupting compounds in 3 pilot-scale and 2 lab-scale membrane bioreactor (MBR) systems. Compared with the overall estrogenicities of sewage treatment plant (STP) effluents from references, the MBR systems studied have relatively good performance in the removal of estrogenicity. Estrone (E1) was removed with relatively high efficiency (80.2-91.4%), but 17beta-estradiol (E2) was removed with moderate efficiency (49.3-66.5%) by the MBRs. However, the experimental results indicated that after the treatment by MBR, substantial amounts of E1, estrone-3-sulfate (E1-3S), estrone-3-glucuronide (E1-3G), and 17beta-estradiol-glucuronides (E2-G) passed through treatment systems and entered into the aquatic environment. The reduction in the levels of overall equivalent E1 (68.4%) and that of overall equivalent E2 (80.8%) was demonstrated for the pilot-scale MBR-B. For alkylphenol compounds, bisphenol A (BPA) was removed well with a removal efficiency of 68.9 -90.1%, but 4-nonylphenol (4-NP) concentration was amplified (removal efficiency of -439.5 to -161.1%) after MBR treatment which could be caused by the transformation of its parent compounds, nonylphenol polyethoxylates (NPnEOs). The amounts of adsorbed estrogens per kg dry mass was relatively low, due to short hydraulic retention time and high mixed liquor suspended solids in MBRs, compared to that in STPs.     

Enhanced biodegradation of iopromide and trimethoprim in nitrifying activated sludge

Iopromide (an X-ray contrast agent) and trimethoprim (an antibacterial drug) are frequently detected pharmaceuticals in effluents of wastewater treatment plants (WWTPs) and in surface waters due to their persistence and high usage. Laboratory-scale experiments showed that a significantly higher removal rate in nitrifying activated sludge as compared to conventional activated sludge was observed for both iopromide and trimethoprim. When the activity of the nitrifying bacteria was inhibited, the percent removal of iopromide decreased from 97 to 86% while trimethoprim removal decreased from 70 to 25%. The metabolite of iopromide identified when nitrification was not inhibited was a dehydroxylated iopromide at the two side chains. However, when the nitrifying bacteria were inhibited the metabolite identified was a carboxylate, formed during the oxidation of the primary alcohol on the side chain of iopromide. These results suggest that the nitrifying bacteria are important in the observed biodegradation of iopromide in the activated sludge with higher solid retention time (SRT). Results from the laboratory-scale study were corroborated by the observed removal efficiencies in a full-scale municipal WWTP, which showed that iopromide (ranging from 0.10 to 0.27 microg/L) and trimethoprim (ranging from 0.0.08 to 0.53 microg/L) were removed more effectively in the nitrifying activate sludge which has a higher SRT (49 days) than in the conventional activated sludge (SRT of 6 days). In nitrifying activated sludge, the percent removal of iopromide in the WWTP reached 61%, while in conventional activated sludge, average removal was negligible. For trimethoprim, removal was limited to about 1% in the conventional activated sludge, while in the nitrifying activated sludge, the removal was increased to 50%.     

Dimethyl sulfide removal from synthetic waste gas using a flat poly(dimethylsiloxane)-coated composite membrane bioreactor

The reduction of volatile organic sulfur emissions should be completely as they cause odor nuisance, even when they are emitted in very small amounts. In general, biofilters are applied for odor reduction, but their operational control is limited. A new biotechnique for the treatment of complex emissions is the use of membranes integrated within bioreactors (MBRs). In this study, the reactor performance of MBRs for removal of dimethyl sulfide (DMS) as a model compound is presented. Composite membranes with a poly(dimethylsiloxane) (PDMS)-coating layer were used. The MBRs were inoculated with the sulfur-degrading culture Hyphomicrobium VS or a suspension of Hyphomicrobium VS, ammonium-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB) to colonize the PDMS-coating layer. Although inoculation with AOB and NOB might give rise to competition for space on the membrane, their presence in the MBRs appeared to be positive as they co-oxidize DMS. Dimethyl sulfide elimination depended on the inoculum type, DMS inlet concentration, gas residence time, and membrane polymer. For equal loading rates, the elimination capacity (EC) increased at larger gas residence times and inlet concentrations. The maximum EC obtained with the MBRs was 4.8 kg of DMS x m(-3) x d(-1). This value is higher than any reported figure for biofilters and biotrickling filters.     

Fate of alkylphenolic compounds during activated sludge treatment: impact of loading and organic composition

The impact of loading and organic composition on the fate of alkylphenolic compounds in the activated sludge plant (ASP) has been studied. Three ASP designs comprising carbonaceous, carbonaceous/nitrification, and carbonaceous/nitrification/denitrification treatment were examined to demonstrate the impact of increasing levels of process complexity and to incorporate a spectrum of loading conditions. Based on mass balance, overall biodegradation efficiencies for nonylphenol ethoxylates (NPEOs), short chain carboxylates (NP(1-3)EC) and nonylphenol (NP) were 37%, 59%, and 27% for the carbonaceous, carbonaceous/nitrification, and carbonaceous/nitrification/denitrification ASP, respectively. The presence of a rich community of ammonia oxidizing bacteria does not necessarily facilitate effective alkylphenolic compound degradation. However, a clear correlation between alkylphenolic compound loading and long chain ethoxylate compound biodegradation was determined at the three ASPs, indicating that at higher initial alkylphenolic compound concentrations (or load), greater ethoxylate biotransformation can occur. In addition, the impact of settled sewage organic composition on alkylphenolic compound removal was evaluated. A correlation between the ratio of chemical oxygen demand (COD) to alkylphenolic compound concentration and biomass activity was determined, demonstrating the inhibiting effect of bulk organic matter on alkylphenol polyethoxylate transformation activity. At all three ASPs the biodegradation pathway proposed involves the preferential biodegradation of the amphiphilic ethoxylated compounds, after which the preferential attack of the lipophilic akylphenol moiety occurs. The extent of ethoxylate biodegradation is driven by the initial alkylphenolic compound concentration and the proportion of COD constituted by the alkylphenol polyethoxylates (APEOs) and their metabolites relative to the bulk organic concentration of the sewage composed of proteins, acids, fats, and polysaccharides. Secondary effluents from this study are characterized by low bulk organic concentrations and comparatively high micropollutant concentrations. Based on the biodegradation mechanism proposed in this study, application of high rate tertiary biological treatment processes to secondary effluents characterized by low bulk organic concentrations and comparatively high APEO concentrations is predicted to provide a sustainable solution to micropollutant removal.     

黄河(兰州段)壬基酚聚氧乙烯醚及其降解产物污染的初步研究

本文以黄河(兰州段)为研究对象,对其流域的4个排污点的水样和6个断面各个介质(包括水体、悬浮颗粒物和沉积物)中壬基酚聚氧乙烯醚(NPnEO)及其降解产物壬基酚的污染进行调查。结果表明,4个排污点水样中分别含有浓度不等的NP;6个断面采样点中,大分子的NPnEO(n>2)在各个介质中均未检出,水样中NP在0.24~2.1μg/L之间,NP1EO在0.060~0.35μg/L之间,NP2EO在0.039~0.26μg/L之间。     

Evaluation of a newly developed enzyme-linked immunosorbent assay for determination of linear alkyl benzenesulfonates in wastewater treatment plants

A recently developed enzyme-linked immunosorbent assay (ELISA) for the determination of linear alkyl benzenesulfonates (LAS) and long chain sulfophenyl carboxylates (SPCs) has been evaluated for its application in wastewater control analysis. This ELISA based on the use of polyclonal antibodies in an indirect format shows an IC50 of 28.1 +/- 3.2 microg L(-1) and a limit of detection (LOD) of 1.8 +/- 0.6 microg L(-1) in buffer. The assay uses antibodies raised through a pseudoheterologous immunization strategy using an equimolar mixture of two immunogens, N-(4-alkylphenyl)sulfonyl-3-aminopropanoic acid covalently coupled to keyhole limped hemocyanin (SFA-KLH) and sulfophenyl carboxylate 13C13 coupled to KLH (13C13-SPC-KLH). The immunizing haptens have been designed to address recognition versus two different epitopes of the LAS molecule. To assess the performance of this immunoassay in complex real samples, a cross reactivity study was carried out, and the possible interference of other surfactants commonly detected in wastewater, including nonylphenol ethoxylates (NPEOs), nonylphenol (NP), octylphenol (OP), and coconut fatty acid diethanol amides (CDEA), have been evaluated. Additionally, a study of the matrix effects of different types of wastewater was achieved. This ELISA has been evaluated and validated by measuring the LAS content of 22 samples collected from the influents and the effluents of six wastewater treatment plants (WWTP) located in Catalonia, Spain. A solid-phase extraction followed by liquid chromatography coupled to mass spectrometry detection (SPE-LC-MS) has been used as a validation method of the new ELISA test.     

NP1EC degradation pathways under oxic and microxic conditions

The degradation pathway of nonylphenol ethoxyacetic acid (NP1EC) and the conditions favoring dicarboxylated alklyphenol ethoxyacetic acid (CAnP1EC; where n = the number of aliphatic carbon atoms) formation were studied in oxic microcosms constructed with organic carbon-poor soil from the Mesa soil aquifer treatment (SAT) facility (Arizona) and pristine organic carbon-rich sediments from Coyote Creek (California). Results suggest that the availability of dissolved oxygen determines the dominant biodegradation pathway; ether cleavage and the formation of NP is favored by oxic conditions, while alkyl chain oxidation and the formation of CAP1ECs is favored under microxic conditions. In the Mesa microcosms, para-NP1EC was transformed to para-nonylphenol (NP) before being rapidly transformed to nonyl alcohols via ipso-hydroxylation. In the Coyote Creek microcosms, large quantities of CAP1ECs were observed. Initially, CA8P1ECs were the dominant metabolites, but as biodegradation continued, CAP1ECs became the dominant metabolites. Compared to the CAsP1ECs, the number of CA6P1ECs peaks observed was small (< 6) even though their concentrations were high. Several novel metabolites, tentatively identified as 3-alkylchroman-4-carboxylic acids (with alkyl groups ranging from C2 to C5), were formed in the Coyote Creek microcosms. These metabolites are presumably formed from ortho-CAP1ECs by intramolecular ring closure.     

Aerobic biodegradation behavior of nonylphenol polyethoxylates and their metabolites in the presence of organic matter

In this paper, the aerobic biodegradation behavior of nonylphenol polyethoxylates (NPnEOs) with ethoxy (EO) units of specific lengths, which were fractionated using high-performance liquid chromatography(HPLC) with photodiode array detection, was studied in the presence of different types of organic materials. NPnEOs and their related metabolites under a modified OECD 301E biodegradation test were monitored using liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS). Biodegradation tests in the presence of organic matters, such as methanol, glucose, and yeast extract, showed the formation of the corresponding nonylphenol polyethoxy carboxylates by the oxidation of the terminal alcoholic group. However, aerobic biodegradation tests without organic matter revealed that NP2EO and NP3EO were predominant metabolites of the long-chain-oligomer precursor system which undergo fast and complete shortening. Degradation rates were higher for the long-chain oligomers than for shorter ones. The degradation pathway of NPnEOs was greatly influenced by the presence or absence of organic matter. Organic materials such as those given above apparently play a significant role in the formation of the carboxylated metabolites of NPnEOs.