The occurrence and removal of phthalates in a trickle filter STW

This study investigated the fate of phthalates in a trickle filter sewage treatment works. A wide variety of phthalates were researched of which only two were present in significant amounts. Mean concentrations of di-(2-ethylhexyl) phthalate (DEHP) and diethyl phthalate (DEP) measured throughout the system were 23.6 and 25.0 microg/l in raw sewage, 22.0 and 24.8 microg/l in primary, 14.6 and 0.60 microg/l in trickle filter, 18.6 and 0.10 microg/l in humus tank and 18.5 and 0.40 microg/l in reedbed effluents, respectively. Removal by the trickle filter was constantly high for DEP (94-99%) whereas DEHP was variable (<1-44%). Mean concentrations of DEHP and DEP in raw sludge were 30.2 and 1.60 microg/g dry wt, respectively. A mass balance for DEHP was calculated using data from field studies and estimates of sludge production at the works. The mass balance approach helped to provide information that could be used to improve the design and operation of sewage treatment works.     

Occurrence and removal of organic pollutants in sewages and landfill leachates

Sewages of different composition and the effluents of four sewage treatment plants (STPs), plus sewage sludges were analysed for semivolatile organic priority pollutants. Furthermore, 11 landfill leachates were analysed to evaluate their contribution to sewage pollutants when co-treated. Bis(2-ethylhexyl) phthalate (DEHP) was the pollutant occurring at highest concentrations (up to 122 microg/l) and it was present in all sewages and leachates; concentrations of other phthalates were usually below 17 microg/l. Some polycyclic aromatic hydrocarbons (PAH) (<1 microg/l) and 2,6-dinitrotoluene (< or =5.9 microg/l) were also present in many of the sewages and leachates. Phthalates were present in STP effluents in low concentrations (<8 microg/l), while PAHs were usually not present. DEHP concentrations were at the same level in the sewage consisting of household wastewater and stormwater runoff and the sewages also including industrial discharges and landfill leachates, while PAHs were present in sewages containing industrial discharges. Leachate contribution to the total pollutant load to the STP was less than 1%. Sorption of DEHP to different particle size fractions in sewage was studied by serial membrane filtration. Most of the DEHP (71-84%) was attached to the particles 0.1-41 microm in size, and approximately 10-27% of the DEHP was sorbed on particles larger than 41 microm. Less than 6% of the DEHP was in the fraction below 0.1 microm and readily available for microbial degradation.     

Occurrence and fate of endocrine disrupters in Greek sewage treatment plants

The occurrence of five endocrine-disrupting compounds (EDCs), namely 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), triclosan (TCS) and bisphenol A (BPA), was assessed in the raw, treated wastewater and sewage sludge of eight sewage treatment plants (STPs) in Greece. The analytes were extracted by solid-phase extraction (dissolved phase) or sonication (solid phase). Qualitative and quantitative analyses were performed by gas chromatography-mass spectrometry (GC-MS). The average concentrations in the raw and treated wastewater ranged from 0.23 (4-n-NP) to 5.76microgL(-1) (NP1EO) and from 0.15 (BPA) to 1.84microgL(-1) (NP2EO), respectively. A great part of the detected EDCs was sorbed on suspended solids. In sewage sludge, the average concentrations ranged between 0.17 (4-n-NP) and 12.3microgg(-1)dw (NP1EO). Analysis of daily mass flows in STP of Athens showed that, with the exception of 4-n-NP, all other EDCs were significantly removed (>85%) during wastewater treatment. Regarding the fate of these compounds, a significant part ranging from 45% (for TCS) to more than 70% (for NP1EO, NP2EO and BPA) was transformed by abiotic or biotic mechanisms, while the rest was accumulated in sewage sludge or disposed to the environment via the effluents. Calculation of risk quotients showed the existence of possible threat due to the presence of certain EDCs in treated wastewater and sludge.     

Degradation of phthalate esters in an activated sludge wastewater treatment plant

Efficient removal of phthalate esters (PE) in wastewater treatment plants (WWTP) is becoming an increasing priority in many countries. In this study, we examined the fate of dimethyl phthalate (DMP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), and di-(2-ethylhexyl) phthalate (DEHP) in a full scale activated sludge WWTP with biological removal of nitrogen and phosphorus. The mean concentrations of DMP, DBP, BBP, and DEHP at the WWTP inlet were 1.9, 20.5, 37.9, and 71.9 μg/L, respectively. Less than 0.1%, 42%, 35%, and 96% of DMP, DBP, BBP, and DEHP was associated with suspended solids, respectively. The overall microbial degradation of DMP, DBP, BBP, and DEHP in the WWTP was estimated to be 93%, 91%, 90%, and 81%, respectively. Seven to nine percent of the incoming PE were recovered in the WWTP effluent. Factors affecting microbial degradation of DEHP in activated sludge were studied using [U-¹⁴C-ring] DEHP as tracer. First order rate coefficients for aerobic DEHP degradation were 1.0×10⁻², 1.4×10⁻², and 1.3×10⁻³ at 20, 32, and 43 °C, respectively. Aerobic degradation rates decreased dramatically under aerobic thermophilic conditions (<0.1×10⁻² h⁻¹ at 60 °C). The degradation rate under anoxic denitrifying conditions was 0.3×10⁻² h⁻¹, whereas the rate under alternating conditions (aerobic-anoxic) was 0.8×10⁻² h⁻¹. Aerobic DEHP degradation in activated sludge samples was stimulated 5-9 times by addition of a phthalate degrading bacterium. The phthalate degrading bacterium was isolated from activated sludge, and maintained a capacity for DEHP degradation while growing on vegetable oil. Collectively, the results of the study identified several controls of microbial PE degradation in activated sludge. These controls may be considered to enhance PE degradation in activated sludge WWTP with biological removal of nitrogen and phosphorus.     

Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant

Bis(2-ethylhexyl) phthalate (DEHP) concentrations were measured at different stages in a full-scale sewage treatment plant (STP) and mass balances were calculated. The DEHP load to treatment process coming from the sewer system and the internal load comprising returned supernatants and filtrate from sludge treatment and excess secondary sludge were at the same level. The DEHP removal efficiency from the water phase at the STP was on average 94% of sewage DEHP, the main removal process being sorption to primary and secondary sludges. On average 29% of DEHP was calculated to be removed in the biological nitrifying-denitrifying activated sludge process, which was much less than expected from laboratory biodegradation studies described in literature. Monoethylhexyl phthalate, the primary biotransformation product of DEHP, was not detected at any treatment stage. Approximately 32% of DEHP in sewage was removed during anaerobic digestion of the sludge, while 32% remained in the digested and dewatered sludge.     

Distribution of linear alkylbenzenes (LABs) in riverine and coastal environments in South and Southeast Asia

This paper reports the result of sewage pollution monitoring conducted in South and Southeast Asia during 1998-2003 using linear alkylbenzenes (LABs) as molecular tracers of sewage contamination. Eighty-nine water samples collected from Malaysia, Vietnam, and Japan (Tokyo), and 161 surface sediment samples collected from Tokyo, Thailand, Malaysia, Philippines, Vietnam, Cambodia, Indonesia, and India were analyzed for alkylbenzenes. The concentration range of SigmaLABs in river water particles in Southeast Asia (<0.005-0.913 microg/L) was comparable to or higher than those found in Tokyo (<0.005-0.638 microg/L). I/E ratios (a ratio of internal to external isomers of LABs) in tropical Asian waters were close to the value of LABs in raw sewage ( approximately 1) and much lower than those in secondary effluents (3-5). This suggests that untreated or inadequately treated sewage is discharged into the water. SigmaLABs concentrations in sediments from South and Southeast Asia ranged from <0.002-42.6 microg/g-dry with the highest concentration occurring at several populous cities. Low I/E ratios of the sediments with high SigmaLABs concentrations suggest a heavy load of untreated sewage. Clearly in view of the current data and evidence of the implications of sewage pollution, this paper highlights the necessity of the continuation of water treatment system improvement in tropical Asia.     

Phthalate removal throughout wastewater treatment plant: Case study of Marne Aval station (France)

The fate of six phthalates: dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBP), bis (2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) was investigated throughout wastewater treatment processes in the wastewater treatment plant (WWTP) of Marne Aval (France). That plant treats wastewater from a highly populated area and was used as a pilot station for development of nitrification processes.In wastewater, at each step of treatment, DEHP was always the major compound (9 to 44 µg L^− 1), followed by DEP (1.6 to 25 µg L^− 1). Other phthalates averaged 1 µg L^− 1 and DnOP remained close to the detection limit in nearly all cases.In sludge, the prevailing compound was also DEHP (72 µg g^− 1) which is consistent with its tendency to get sorbed upon suspended matter (SM). DnOP came in third, in relation with its resistance to biodegradation.For the studied period, the removal efficiency of DEHP from wastewater was about 78%. That removal seemed to proceed rather from particle settling than from biodegradation. A highly significant correlation (p < 0.001) was found between DEHP and SM concentrations throughout treatment processes. The other compounds: DMP, DEP, DnBP and BBP, displayed satisfactory efficiencies ranging from 68 to over 96% for the lighter ones obviously more easily degraded.Under rainy periods, the plant discharge impact upon Marne River quality in terms of phthalate fluxes, appeared to be minor as compared to the amount brought by the storm overflows in the same area. Downstream of the WWTP discharge, DEHP concentration remained under the European norm for surface water (NQE: 1.3 µg L^− 1).Our study documents the behaviour of phthalate esters throughout a WWTP which treatment device is used by 55% of the WWTP in the river Seine basin.     

Atmospheric fate of phthalate esters in an urban area (Paris-France)

The atmospheric fate of six phthalate esters was investigated in the urban area of Paris (France). Total atmospheric levels (ng m-3) were as follows: DMP, 0.5; DEP, 10.7; DnBP, 22.2; BBP, 4.6; DEHP, 18.9; and DnOP, 0.5 ng m-3, showing a predominance of DnBP and next, DEHP. They are mainly present in the vapour phase, from 93.8% to 64.9%, particularly for the esters with alkyl chain length of less than six C. An inverse correlation was found between the vapour phase concentrations and the molecular weight and also a direct correlation between the vapour phase concentrations and the log [vapour pressure] of the compounds. Seasonal variations were displayed by principal component analysis (PCA), due to significant correlation between phthalate concentrations and air temperature. Rain water concentrations (ng L-1) were as follows: DMP, 116; DEP, 333; DnBP, 592; BBP, 81; DEHP, 423; and DnOP, 10. PCA analysis showed a seasonal variation of these concentrations correlated to the air temperature. The experimental water/air scavenging ratio was calculated and was in accordance with the theoretical one obtained from the vapour pressure and the Henry's law constant for each phthalate ester. The global trend was a decrease of the washout coefficient in relation with the rise of alkyl chain length. Yearly balances for rainwater and bulk deposition allowed the estimation of dry deposits that represented about half of total. Our findings highlight the major part played by particles in atmospheric deposition processes.     

Phthalates and nonylphenols in profiles of differently dressed soils

The concentrations of nonylphenols and phthalates in depth profiles of eight differently dressed, fertilised and cultured fields were investigated. The fields were typical for Danish agriculture and comprised an uncultured location, two manured fields, an artificially fertilised field and three fields amended with different amounts of sewage sludge. In addition, a location receiving run-off from a sewage sludge storage facility were investigated. At each location, two 50 cm vertical soil cores were taken, divided into sections of 10 cm each and analysed for nonylphenols and phthalates by high-resolution mass spectrometry. Di-(2-ethylhexyl)-phthalate (DEHP) was the most abundant phthalate in all samples whereas Di-(n-butyl)-phthalate (DBP) played a minor role. Nonylphenols occurred in significant concentrations only in soil samples exposed to high amounts of sludge and at the run-off location. A close relationship was found between the concentrations of contaminants in the soil samples and the method of dressing. The concentrations were low at comparable levels in the soil samples from the artificially fertilised field and in the fields amended with low amounts of sludge, as well as in the manured fields. Remarkably, these concentrations did not differ significantly from the level in an uncultured recreational preserved area, which was used as a reference. In contrast, much higher levels of contaminants were found in the soil samples from fields exposed to high amounts of sludge. We must conclude that sludge amendment below a certain limit does not lead to elevated levels of nonylphenols and phthalates in the soils, whereas heavy sludge amendment leads to the accumulation of these contaminants. For the vertical distribution of substances in the soils, an influence of soil characteristics on the concentration profile was noted. Thus, in soils with visible clay in the upper layers, a DEHP maximum occurred at a depth of 10-20 cm, whereas in most sandy soils no such maximum was observed. A 2-year time trend study of the highly sludge amended soil showed no measurable reduction in the substances during this period. The time study further suggested a downward movement of the DEHP maximum of approximately 10 cm per year.     

Environmental risk assessment of antibiotics in the Swedish environment with emphasis on sewage treatment plants

The potential risks associated with antibiotics present in the Swedish environment were assessed using concentrations found in hospital effluent, and sewage treatment waters and sludge, in combination with data on their environmental effects obtained from the literature. For the aqueous environment, measured environmental concentrations and effect/no observed effect concentration ratios were much lower than one in most cases. The only exceptions, where concentrations of the investigated substances were high enough to pose potential risks, were the concentrations of the two fluoroquinolones, ofloxacin and ciprofloxacin, in the hospital effluent. Treating digested dewatered sludge by heat did not fully eliminate norfloxacin or ciprofloxacin, thus pellets may still contain high amounts of these substances (sub to low mgkg(-1)dw). In leaching tests less than 1% of the amounts of these fluoroquinolones in the sludge or pellets reached the aqueous phase, indicating that their mobility is limited if sludge is used to fertilize soil.     

A preliminary study on the occurrence and behavior of sulfonamides, ofloxacin and chloramphenicol antimicrobials in wastewaters of two sewage treatment plants in Guangzhou, China

Wastewater samples collected from two sewage treatment plants (STPs) in Guangzhou, China were acidified, solid-phase extracted (SPE) with Oasis HLB cartridges, followed by instrumental measurement by high performance liquid chromatography (HPLC) coupled with a diode array UV detector (DAD) and a fluorescence detector (FLD) for the occurrence and fate of antimicrobial compounds sulfadiazine (SDZ), sulfamethoxazole (SMX), ofloxacin (OFX) and chloramphenicol (CAP). Antimicrobials have been detected at 5.10-5.15, 5.45-7.91, 3.52-5.56 and 1.73-2.43 microg L(-1) for SDZ, SMX, OFX and CAP in the raw sewages of the two STPs, respectively. The concentrations of antimicrobials do not show substantial changes after preliminary mechanical sedimentation. No quantifiable sulfonamides and chloramphenicol have been identified, and >85% of ofloxacin has been removed in the effluents after activated sludge treatment in the two STPs, indicating that activated sludge treatment is effective and necessary to remove antimicrobial substances in municipal sewage.     

Phthalates and nonylphenols in urban runoff: Occurrence, distribution and area emission factors

The urban water system is believed to be an important sink for the nonpoint-source pollutants nonylphenols and phthalates. The presence of nonylphenols (NPs), nonylphenol ethoxylates (NPEOs), and eight phthalates was analyzed in urban stormwater and sediment from three catchment areas in Sweden. Emission loads for these substances were then calculated for a specific urban catchment area. In addition, substance distribution in road runoff passing through a sedimentation facility was modeled using a modified QWASI-model for chemical fate. High concentrations of DEHP, DIDP and DINP (≤ 48, 66 and 200 µg/g dw, respectively) as well as nonylphenol mono- and di-ethoxylate (6.6 and 20 µg/g dw, respectively) were found in the sediment. Aqueous concentrations of the pollutants varied considerably; branched NP was detected in concentrations up to 1.2 µg/L, whereas di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and diisononyl phthalate (DINP) were the most frequently detected phthalates in concentrations up to 5.0, 17 and 85 µg/L, respectively. The fate modeling demonstrated that predicted substance levels in water agreed well with measured levels, whereas the modeled sediment levels were underestimated. Calculation of catchment area emission factors from an urban highway environment revealed that as much as 2.1 kg of total phthalates and 200 g of NP and NPEOs may be emitted per hectare and year. The results indicate that all monitored phthalates, branched NPs and lower NPEOs are present in Swedish urban water systems. The long-chain phthalates DIDP and DINP are believed to occur at higher concentrations than other phthalates because of their higher environmental persistence and their increasing use in Sweden.     

Fate and removal of selected endocrine‐disrupting compounds in sewage using activated sludge treatment

The variation and fate of four endocrine‐disrupting compounds (EDCs) composed of 4‐n‐nonylphenol (4‐n‐NP), bisphenol A (BPA), 17β‐estradiol (E2) and 17α‐ethinylestradiol (EE2) were investigated along treatment units in a sewage treatment plant (STP), China with anaerobic, anoxic and aerobic activated sludge processes. The mean concentrations were 64.8 ng/L (E2), 115.3 ng/L (4‐n‐NP), 171.5 ng/L (EE2), and 920.7 ng/L (BPA) in the influents, and 22.8 ng/L (E2), 50.9 ng/L (4‐n‐NP), 49.9 ng/L (EE2), and 84.3 ng/L (BPA) in the effluents. The biological treatment was more effective in removing NP, BPA and E2 from the aqueous phase than the primary treatment, while the latter could effectively remove EE2. Their possible removal mechanisms during the biological treatment with activated sludge were further explored through spiked batch experiments under three oxygen‐supplying conditions (anaerobic, anoxic and aerobic). The batch experiments showed that 4‐n‐NP, E2 and BPA were removed from the aqueous phase through biodegradation. The combination of sludge sorption and biodegradation accounted for the removal of EE2. Anoxic activated sludge showed the most rapid degradation of 4‐n‐NP, while E2 could be removed most effectively by aerobic activated sludge, and sludge sorption had a remarkable effect on its removal within the initial 15 min of the experiments under three oxygen‐supplying conditions.     

Fish test for endocrine-disruption and estimation of water quality of Japanese rivers

The LC50 values (72 h) of 17beta-estradiol (E2), p-nonylphenol (NP) and bis-phenol-A (BPA) to adult male and female medaka were 3.5 and 3.5, 0.85 and 0.87, and 6.8 and 8.3 mg L(-1), respectively; the LC50 values to embryos were 0.46, 0.13 and 5.1 mg L(-1), respectively. The IC50 values for inhibition to egg hatching were 0.47, 0.85 and 9.0 mg L(-1), respectively. These values were much higher than concentrations detected in river water in Japan and the chemicals were considered to have no lethal effect on the fish in an aquatic environment. Mature male medaka was continuously exposed to 0.005, 0.05 or 1.0 microg L(-1) of E2, or to 0.1, 10 or 100 microg L(-1) of NP or BPA. Female specific proteins (FSP) were induced in the blood of male medaka that were exposed for 5 weeks to E2 higher than 0.005 microg L(-1), NP higher than 0.1 microg L(-1), or BPA higher than 10 microg L(-1). Based on these FSP inducible concentrations and reported concentrations of E2, NP and BPA in Japanese river water, some river water contaminated by E2 or NP could be estimated as the FSP inducible in male medaka.     

Identifying model pollutants to investigate biodegradation of hazardous XOCs in WWTPs

Xenobiotic organic compounds (XOCs) in wastewater treatment plant (WWTP) effluents might cause toxic effects in ecosystems. Several investigations have emphasized biodegradation as an important removal mechanism to reduce pollution with XOCs from WWTP effluents. The aim of the study was to design a screening tool to identify and select hazardous model pollutants for the further investigation of biodegradation in WWTPs. The screening tool consists of three criteria: The XOC is present in WWTP effluents, the XOC constitutes an intolerable risk in drinking water or the environment, and the XOC is expected to be biodegradable in WWTPs. The screening tool was tested on bisphenol A (BPA), carbamazepine (CBZ), di(2ethylhexyl)-phthalate (DEHP), 17beta-estradiol (E2), estrone (E1), 17alpha-ethinyloetradiol (EE2), ibuprofen, naproxen, nonylphenol (NP), and octylphenol (OP). BPA, DEHP, E2, E1, EE2, and NP passed all criteria in the screening tool and were selected as model pollutants. OP did not pass the filter and was rejected as model pollutant. CBZ, ibuprofen, and naproxen were not finally evaluated due to insufficient data.     

Identification of organic compounds and ecotoxicological assessment of sewage treatment plants (STP) effluents

An integrated approach combining chemistry and biological methods was conducted to assess the toxicity of seven sewage treatment plant effluents. Solid phase concentration procedures were applied to facilitate the study of organic micro pollutants. A chemical analysis was performed by GC/MS. Organic fraction toxicity was determined by using bioassays such as Daphnia magna and Chlorella vulgaris tests and sub-lethal effects were also evaluated by using Salmonella typhimurium Test (mutagenicity), recombinant yeast screen (estrogenicity), and Oryzias latipes embryo-larval test. More than 49 compounds were detected in the organic fraction due to the various inputs of each effluents. The most frequently detected compounds in the effluents were bisphenol A (BPA), octylphenol (OP), 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (DEHP) and 1,2-benzenedicarboxylic acid, bis(methylpropyl) ester (DBP). Biological assays showed toxicity effects on D. magna tests in all samples, whereas toxicity on C. vulgaris or S. typhimurium tests were not observed. Estrogenicity and teratogenicity were observed in several samples. The cause-effect relationship could not be established given the high chemical complexity of the effluents and the lack of information available on 70% of the detected compounds subsequent to reviewing various data bases. Nevertheless, due to the high chemical variability revealed by STP effluents, bioassay sets may provide a very useful amount of information for detecting potential toxicity risks.     

Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation

Organotin (OT) compounds, namely butyl and phenyl, were measured in 38 recent sediments collected in harbours of the Western Mediterranean Sea (Northern: 4 and Southern: 9) and domestic and industrial sewage disposal sites (Northern: 9 and Southern: 1). Butyltins were the predominant tin species identified as being tributyltin (TBT) widespread in the whole area which suggests recent inputs of OTs. The highest levels of TBT were detected in commercial harbours associated with inputs from large vessels (average value: 5.0 microg TBT g(-1). Moreover, relatively high TBT values were also detected in fishing and recreational boating areas (average level ca. 1.0 microg TBTg(-1)). Phenyltin derivatives occurred at lower levels than butyltins being the monophenyltin the predominant compound (average values 45-945 ng g(-1)). The large predominance of the phenyltin degradation products (i.e. mono and diphenyltin) over the parent compound (i.e. triphenyltin) suggests that there are almost no recent inputs of these compounds. Furthermore, a comparative study of the OT occurrence in the sewage sludge disposal sites offshore Barcelona and Almeria (domestic) and into the Tarragona harbour (industrial) shows that domestic primary sewage sludge effluents can contribute to coastal OT pollution (244ng TBT g(-1)). Nevertheless, sewage sludge is a secondary source of OT contamination in the coastal environment in comparison to commercial harbours. In a comparative study with previous data collected in the late 1980s, the present study reveals that OT regulations established in the Mediterranean region in 1991 on the use of TBT-based antifouling paints have been effective in marinas, but reveals a significant TBT contamination in commercial and fishing harbours.     

上海城市污泥中HBCD的浓度及土地施用累积水平

利用索氏提取、凝胶渗透色谱及高效液相色谱/质谱联用方法分析了上海市27个污水处理厂最终污泥中六溴环十二烷(HBCD)的浓度及分布情况。结果表明,污泥中HBCD的浓度范围为0.103～37.220 ng/g干重,平均值为4.700 ng/g干重,与世界其他地区相比,污染水平较低。在其中17个样品中,γ-HBCD是主要成分(44.7%～76.3%),在其他10个样品中,α-HBCD所占比例最高(49.6%～90.6%)。据估算,上海市通过污泥每年排放HBCD的量为1.5 kg。污泥如未经处理直接进行土地施用,土壤中HBCD的残留浓度会高出近似背景区一个数量级。     

Occurrence and elimination of antibiotics at four sewage treatment plants in the Pearl River Delta (PRD), South China

In this paper, the occurrence and elimination of eight selected antibiotics mainly for human use, including chloramphenicol, fluoroquinolone, sulfonamide and macrolide groups, were investigated at four sewage treatment plants (STPs) in the Pearl River Delta (PRD), South China. The most frequently detected antibiotics in the present study were ofloxacin, norfloxacin, roxithromycin, erythromycin-H(2)O (the main degradation product of erythromycin) and sulfamethoxazole. The concentrations of these compounds in raw influents and final effluents at the four STPs ranged from 10 to 1978 ngL(-1) and from 9 to 2054 ngL(-1), respectively. The other analytes were detected only in a few samples from the four STPs. Antibiotics could not be eliminated completely at the four STPs, with the highest elimination efficiency reaching to 81%. Analysis of the dissolved daily mass flow showed that fluoroquinolones were mostly eliminated from the sewage, and high concentrations of these compounds were found in secondary sludge. Therefore, it can be concluded that the observed elimination of fluoroquinolones in the STPs was due to their sorption to the sludge, but not biodegradation. Macrolides, especially erythromycin-H(2)O, were stable in sewage during the treatment process, and in fact even higher concentrations were found in the final effluents than in the raw sewages. Sulfamethoxazole was also found in raw influent and final effluent, indicating that it could withstand different treatment processes in the STPs. Remarkable differences in the daily environmental loads (the sum of the amounts in the final effluent and sludge) of the five most frequently detected antibiotic compounds were found in the range of 0.5-828 g at the four STPs.     

Effects of exposure of ewes to sewage sludge-treated pasture on phthalate and alkyl phenol concentrations in their milk

Concentrations of endocrine disrupting compounds (EDCs) of two classes, the alkyl phenols (nonyl phenol (NP) and octyl phenol (OP)) and phthalates, in the milk of ewes grazed on pastures fertilised with sewage sludge or with inorganic fertiliser were determined at three stages of lactation. Milk concentrations of these compounds varied greatly between individuals and stages of lactation for both nonyl phenol (NP; < 30-> 1000 microg/kg DM) and total phthalates (< 200-> 20,000 microg/kg DM). Overall, there was no significant effect of sludge treatment on milk concentrations of chemicals of either class. Significant differences between years were recorded in mean log concentrations of both NP (P < 0.001) and total phthalate (P < 0.001) but there were no consistent changes with stage of lactation, ewe body condition or age in mean milk concentrations of either class of compound. Milk concentrations of NP were low, and little higher than environmental concentrations, while phthalate concentrations were approximately two-fold higher than environmental concentrations. Estimated daily intakes of phthalates were considered to be of potential, biological significance with respect to the health of animal and human consumers. It is concluded that the importance of milk as a route of EDC exposure in growing ruminants differs with class of compound and individual animal. Exposure of the offspring to these EDCs may be transiently exacerbated by exposure of their dams to additional EDCs via the application of sewage sludge to their pasture.