Removal of estrogenicity in Swedish municipal sewage treatment plants

The human estrogen receptor alpha-test, hosted in a yeast strain, was used to quantify estrogenicity in three-week composite samples of untreated and treated effluents from 20 Swedish municipal sewage treatment plants. The treatment plants were selected to represent different treatment processes regarding chemical precipitation and microbial procedures. The discharge from Swedish domestic sewage treatment plants contained estrogenic compounds corresponding to <0.1-15 ng estradiol equivalents/L. Low levels of estrogenic activity were also found in a river receiving municipal effluents, 3.5-35 km downstream the outlet from a sewage treatment works. The range of estrogenicity in untreated, raw sewage effluents was found to be 1-30 ng estradiol equivalents/L. Generally, wastewater treatment reduced the estrogenicity and extended biological treatment was most effective in its removal. Activated sludge treatment tended to be more effective than trickling filters, whereas chemical precipitation using iron or aluminium salts without biological treatment showed little effectivity. The study showed that treatment methods in current use are able to eliminate or largely reduce estrogenicity in domestic wastewater.     

Occurrence of androgens in sewage treatment plants influents is associated with antagonist activities on other steroid receptors

The occurrence of endocrine disrupting chemicals such as estrogens in raw urban sewage is well documented. By contrast, the presence of other steroidal activities in wastewater has been poorly studied, although they can cause undesirable biological responses in the environment. In this work, extracts of raw wastewater were tested for agonist and antagonist activities on estrogen, androgen, progesterone, mineralocorticoid and glucocorticoid receptors. We detected strong estrogenic activities that correlated well with the concentration of natural estrogens (estrone, estriol and 17β-estradiol) measured by chemical analysis. We also measured strong androgenic activities which were not due to estrogen receptor ligands based on the use of recombinant estrogen receptor α affinity columns. Several molecules with androgenic activities were identified in wastewater samples, testosterone, dihydrotestosterone and epiandrosterone being the most abundant. However, they explain only a small part of the detected androgenic activity, as indicated by the comparison of the detected biological responses with the results of the targeted chemical analysis. Finally, we found that our samples also contained strong antagonist activities on progesterone, glucocorticoid and mineralocorticoid receptors. Very interestingly, we identified pregnenolone (the precursor to all steroid hormones in humans) as a major endocrine disrupting chemical which accounts for most of the anti-mineralocorticoid activities present in raw wastewater. In conclusion, this study demonstrates the occurrence of androgen agonists as well as other steroid receptor antagonists such as pregnenolone in raw wastewater. Further research is needed to assess the fate of such compounds during sewage treatment and their potential effect on living organisms.     

Effect of duration of exposure to sewage sludge-treated pastures on liver tissue accumulation of persistent endocrine disrupting compounds (EDCs) in sheep

Liver tissue concentrations of selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) were determined in groups of Texel ewes and lambs following exposure to pastures fertilised with either sewage sludge (Treated; T) or inorganic fertiliser (Control; C). Lambs were slaughtered at the age of 6 months, in each of 3 years, while ewes were slaughtered at 5 to 6 years of age having been exposed to the respective pastures for approximately 6, 18 or 30 months, during the same, respective years, immediately before slaughter. Mean liver concentrations of very few of the chemical classes were elevated in either ewe or lamb tissue as a result of exposure of the animals to sewage sludge. Mean concentrations, in lamb liver, of chemicals of each of the classes differed significantly, but inconsistently, between years, reflecting temporal variations in exposure, although the pattern of annual change differed with individual chemical. On the other hand, in ewes, liver concentrations of many chemicals increased, significantly and consistently, with increasing duration of exposure. It was concluded that the increases in tissue concentrations with increased duration of exposure were unlikely to be sufficient to be of concern to consumers and that tissue burdens cannot be linked, easily, with the physiological effects reported previously for animals similarly exposed.     

Comparing steroid estrogen, and nonylphenol content across a range of European sewage plants with different treatment and management practices

The effluent of 17 sewage treatment works (STW) across Norway, Sweden, Finland, The Netherlands, Belgium, Germany, France and Switzerland was studied for the presence of estradiol (E2), estrone (E1), ethinylestradiol (EE2) and nonylphenol (NP). Treatment processes included primary and chemical treatment only, submerged aerated filter, oxidation ditch, activated sludge (AS) and combined trickling filter with activated sludge. The effluent strength ranged between 87 and 846 L/PE (population equivalent), the total hydraulic retention time (HRT) ranged between 4 and 120 h, sludge retention time (SRT) between 3 and 30 d, and water temperature ranged from 12 to 21 °C. The highest estrogen values were detected in the effluent of the STW which only used primary treatment (13 ng/L E2 and 35 ng/L E1) and on one occasion in one of the STW using the AS system (6.5 ng/L E2, 50.5 ng/L E1, but on three other occasions the concentrations in this STW were at least a factor of 6 lower). For the 16 STW employing secondary treatment E2 was only detected in the effluent of six works during the study period (average 0.7-5.7 ng/L). E1 was detected in the effluent of 13 of the same STW. The median value for E1 for the 16 STW with secondary treatment was 3.0 ng/L. EE2 was only detected in two STW (1.1, <0.8-2.8 ng/L). NP could be detected in the effluent of all 14 STW where this measurement was attempted, with a median of 0.31 μg/L and values ranging from 0.05 to 1.31 μg/L. A comparison of removal performance for E1 was carried out following prediction of the probable influent concentration. A weak but significant (α<5%) correlation between E1 removal and HRT or SRT was observed.     

Occurrence and implications of estrogens and xenoestrogens in sewage effluents and receiving waters from South East Queensland

We report a survey on the occurrence of estrogens (estrone, E1; 17β-estradiol, E2; 17α-ethynylestradiol, EE2) and xenoestrogens (bisphenol-A, BPA; 4-t-octylphenol, 4-t-OP; 4-nonylphenols, 4-NP; and nonylphenol mono- and di-ethoxylates, NPE1 and NPE2) in effluents from five wastewater treatment plants and their receiving waters in South East Queensland. The total xenoestrogen concentrations in effluent ranged between 2446 ng/L and 6579 ng/L, with 4-NP and NPE1-2 having much higher concentration levels than BPA and 4-t-OP. The estrogen levels in effluent varied from 9.12 to 32.22 ng/L for E1, from 1.37 ng/L to 6.35 ng/L for E2 and from 0.11 ng/L to 1.20 ng/L for EE2. No significant differences (p < 0.05) in the concentrations of the selected estrogenic compounds were found for the effluents from the five sewage treatment plants. The estrogens and xenoestrogens were also found in the receiving waters at relatively lower concentration levels due to dilution of effluents in the rivers. Based on the chemical analysis data and relative potency of the compound from in vitro and in vivo bioassays from the literature, the calculated in vitro EEQ values (estrogen equivalents) in the receiving river waters downstream of the effluent discharge points ranged from 1.32 to 11.79 ng/L, while the in vivo EEQ values (vitellogenin response in rainbow trout) ranged from 2.48 to 21.18 ng/L. The three estrogens accounted for the majority of the EEQ in the water samples. This study indicates that the rivers of South East Queensland are at potential risk.     

Separate estimation of adsorption and degradation of pharmaceutical substances and estrogens in the activated sludge process

The removal of three estrogens such as 17beta-estradiol, two endocrine disruptors like bisphenol A, and 10 pharmaceutical substances like ibuprofen (IBP) by activated sludge was experimentally examined. The contribution of adsorption and degradation to the overall removal was estimated separately and successfully. At the neutral pH condition, the target pharmaceutical substances showed little tendency of adsorption to the sludge and their water-sludge partition coefficients were lower than those of the target estrogens. On the other hand, the increasing tendency of adsorption was observed in the lower pH condition. A linear relationship between the log of the partitioning coefficient and logK(ow) was observed when pH was lowered to keep the pharmaceuticals neutral solutes. The acidic operational condition was preferable for the removal of acidic pharmaceutical substances because the limiting stage for the removal was not biodegradation but the transfer of substances from the water phase to the sludge phase.     

Analysis of environmental endocrine disrupting chemicals using the E-screen method and stir bar sorptive extraction in wastewater treatment plant effluents

Endocrine disrupting chemicals (EDCs) have become a major issue in the field of environmental science due to their ability to interfere with the endocrine system. Recent studies show that surface water is contaminated with EDCs, many released from wastewater treatment plants (WWTP). This pilot study used biological (E-screen assay) and chemical (stir bar sorptive extraction-GC-MS) analyses to quantify estrogenic activity in effluent water samples from a municipal WWTP and in water samples of the recipient river, upstream and downstream of the plant.The E-screen assay was performed on samples after solid phase extraction (SPE) to determine total estrogenic activity; the presence of estrogenic substances can be evaluated by measuring the 17-β-estradiol equivalency quantity (EEQ). Untreated samples were also assayed with an acute toxicity test (Vibrio fischeri) to study the correlation between toxicity and estrogenic disruption activity.Mean EEQs were 4.7 ng/L (± 2.7 ng/L) upstream and 4.4 ng/L (± 3.7 ng/L) downstream of the plant, and 11.1 ng/L (± 11.7 ng/L) in the effluent. In general the WWTP effluent had little impact on estrogenicity nor on the concentration of EDCs in the river water. The samples upstream and downstream of the plant were non-toxic or weakly toxic (0 < TU < 0.9) while the effluent was weakly toxic or toxic (0.4 < TU < 7.6). Toxicity and estrogenic activity were not correlated.At most sites, industrial mimics, such as the alkylphenols and phthalates, were present in higher concentrations than natural hormones. Although the concentrations of the detected xenoestrogens were generally higher than those of the steroids, they accounted for only a small fraction of the EEQ because of their low estrogenic potency. The EEQs resulting from the E-screen assay and those calculated from the results of chemical analyses using estradiol equivalency factors were comparable for all samples and closely correlated.     

The solids retention time-a suitable design parameter to evaluate the capacity of wastewater treatment plants to remove micropollutants

Micropollutants as endocrine disrupting compounds (EDC) or pharmaceuticals are of increased interest in water pollution control. Wastewater treatment plant (WWTP) effluents are relevant point sources for residues of these compounds in the aquatic environment. The solids retention time (SRT) is one important parameter for the design of WWTPs, relating to growth rate of microorganisms and to effluent concentrations. If a specific substance is degraded in dependency on the SRT, a critical value for the sludge age can be determined. In WWTPs operating SRTs below this critical value, effluent concentrations in the range of influent concentrations or a distribution according to the adsorption equilibrium have to be expected, whereas in WWTPs operating at SRTs higher than the critical value degradation will occur. Critical SRTs were determined for different micropollutants, indicating that the design criteria based on the sludge age allows an estimation of emissions. Different treatment technologies as conventional activated sludge systems and a membrane bioreactor were considered and no significant differences in the treatment efficiency were detected when operated at comparable SRT. The results of the investigations lead to the conclusion that low effluent concentrations can be achieved in WWTPs operating SRTs higher than 10 days (referred to a temperature of 10 degrees C). This corresponds to the requirements for WWTPs situated in sensitive areas according to the urban wastewater directive of the European Community (91/271/EEC) in moderate climatic zones.     

A review of phytoestrogens: Their occurrence and fate in the environment

Phytoestrogens are plant compounds with estrogenic activities. Many edible plants, some of which are common in the human diet, are rich in phytoestrogens. Almost all phytoestrogens eaten daily by people were reported partly recovered in urine or feces, which can be regarded as one of the main sources of their occurrence in municipal wastewaters. As they may act as one part of the endocrine disrupting compounds (EDCs) in water systems, some phytoestrogens have been monitored and detected in wastewater and other various environments. It is very difficult to monitor numerous unknown EDCs in complex wastewater samples, and it is helpful if some estimation of target EDCs can be done before monitoring. With this in mind, this review will: (1) summarize estrogenic activities or estrogenic potencies of phytoestrogens by different bioassays; (2) summarize daily urinary excretion rates of phytoestrogens by humans, and compare their urinary excretion rates to that of estrone, which suggests that most phytoestrogens may occur in municipal wastewaters; (3) collect and summarize published data on the occurrence and fate of phytoestrogens in various environments.     

Occurrence and removal of pharmaceuticals in a municipal sewage treatment system in the south of Sweden

The occurrence and removal rate of seven pharmaceuticals (ibuprofen, naproxen, diclofenac, fluoxetine, ofloxacin, norfloxacin, ciprofloxacin), two metabolites (norfluoxetine, clofibric acid), one degradation product (4-isobutylacetophenone) and 3 estrogens (17α-ethinylestradiol, 17β-estradiol, estrone) were studied in the inlet and outlet of a tertiary sewage treatment plant (STP) in Sweden as well as between different treatment steps in the STP which includes a conventional activated sludge step. Pharmaceuticals in raw household and raw hospital sewage streams leading to the STP were as well investigated. Hydraulic retention times (HRT) of each treatment step was considered for sampling and for the calculation of the removal rates. These rates were above 90%, except for diclofenac, clofibric acid, estrone and ofloxacin. However, only diclofenac and naproxen showed significant effluent loads (> 145 mg/d/1000 inh). Diclofenac was not eliminated during the treatment and in fact even higher concentrations were found at the effluent than in the inlet of the STP. 17α-Ethinylestradiol was not detected in any of the samples. Results indicate that a STP such as the one in Kristianstad, Sweden, with a tertiary treatment is sufficient to remove significantly most of the investigated pharmaceuticals. The chemical treatment improved the removal of several pharmaceuticals especially the antibiotics, which showed step removal rates between 55 and 70%. The expected concentration levels of the pharmaceuticals in the surface water (dilution 1 to 10) close to the outlet of the STP are below the no-observed effect-concentration (NOEC). However, despite that this would imply no important effects in the aquatic environment one cannot rule out negative consequences nearby the STP because most of the NOEC values are derived from acute toxicity data. This may underestimate the real impact of pharmaceuticals in the aquatic ecosystem.     

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.     

Evaluation of the fate of perfluoroalkyl compounds in wastewater treatment plants

Recent studies have shown that the wastewater treatment plant (WWTP) is a significant source of perfluoroalkyl compounds (PFCs) in natural water. In this study, 10 PFCs were analyzed in influent and effluent wastewater and sludge samples in 15 municipal, 4 livestock and 3 industrial WWTPs in Korea. The observed distribution pattern of PFCs differed between the wastewater and sludge samples. Perfluorooctane sulfonate (PFOS) was dominant in the sludge samples with a concentration ranging from 3.3 to 54.1 ng/g, whereas perfluorooctanoic acid (PFOA) was dominant in wastewater and ranged from 2.3 to 615 ng/L and 3.4 to 591 ng/L in influent and effluent wastewater, respectively. Principal component analysis (PCA) results provided an explanation for this variation in PFC distribution patterns in the aqueous and sludge samples. The fates of PFCs in the WWTPs were related with the functional groups. The PFOS concentrations tended to decrease after treatment in most WWTPs, whereas PFOA increased. The different fates of PFOA and PFOS in WWTPs were attributed to the higher organic carbon-normalized distribution coefficient of perfluoroalkylsulfonate (PFASs) than that of the carboxylate analog, indicating the preference of PFASs to partition to sludge. Although industrial WWTPs contained high concentration of PFCs, they are not the main source of PFCs in Korean water environment because of their small release amount. WWTPs located in big cities discharged more PFCs, suggesting household sewage is one of the significant sources of PFCs contamination in the environment.     

Seasonal and time variability of heavy metal content and of its chemical forms in sewage sludges from different wastewater treatment plants

Sewage sludges obtained from seven wastewater treatment plants from the province of Salamanca, Spain, were periodically sampled to determine seasonal and time variation of their elemental composition over 2000 to 2002. The aim of this paper was to provide additional insight to evaluate the potential environmental impact following soil incorporation of these materials as amendments. Aqua regia extractable metals (pseudo total content) of Cd, Cr, Cu, Ni, Pb and Zn were determined and furthermore, the main chemical forms of metals within the sludge were evaluated using a five-step fractionation procedure. All the studied sludges displayed high fertility properties due to their richness of OC, P and K. Total mean concentrations of Cd, Cr, Cu, Ni, Pb and Zn in the sludges were within the regulation of the Spanish legislation. Using an multifactor analysis of variance, significant differences between Cr, Cu, Ni, Pb and Zn pseudo total contents (p<0.01) of sludges at different sites were found while the Cd content was statistically similar. Also significant differences were found between these pseudo total contents of heavy metals in samples collected along the time after three years (0.001相似文献   

Evaluation of selected ubiquitous contaminants in the aquatic environment and their transformation products. A pilot study of their removal from a sewage treatment plant

A simple method using direct sample injection combined with liquid chromatography tandem mass spectrometry has been developed for the simultaneous analysis of six alkaloid compounds in environmental samples. The target list includes two psychostimulants (nicotine and caffeine), three metabolites (cotinine, nicotinic acid and paraxanthine) and a coffee chemical (trigonelline). The analytical method was evaluated in three different matrices (surface water, influent and effluent wastewater). The method developed showed an adequate sensitivity, below 0.6 μg L⁻¹ for wastewater and 0.1 μg L⁻¹ for river matrices, without any prior treatment of the samples. Finally, the methodology was applied to real samples for evaluation of their removal from a sewage treatment plant and their persistence/fate in the aquatic environment. All compounds studied in this work were detected at all sampling points collected along the Henares River. However, nicotinic acid was only detected three times in treated sewage samples at levels above its detection limit.