Rejection of pharmaceutically active compounds and endocrine disrupting compounds by clean and fouled nanofiltration membranes

Rejections of 9 pharmaceuticals and 5 endocrine disruptors by clean and fouled nanofiltration membranes were investigated in this study. Waters containing a cocktail of compounds were filtered by clean and pre-fouled membranes. The rejection of hydrophilic neutral compounds by the clean NF-200 membrane varied from 35 to 70% under steady state conditions while that of NF-90 membrane was in the range of 62-96%. The clean NF-90 membrane rejected nearly all of the hydrophobic neutral compounds (95-98%) predominantly due to size exclusion. Nevertheless, electrostatic repulsion was the main mechanism of rejection of ionic compounds by both membranes (71-94% by NF-200 and 99% by NF-90). Fouling with sodium alginate deteriorated the performance of the NF-200 membrane in rejecting hydrophilic neutral compounds as well as hydrophilic and hydrophobic ionic compounds. In contrast, rejections of hydrophobic neutral compounds by the fouled NF-200 membrane increased by 5-38%. This may be attributed to the incipient interaction of the solutes with the membrane foulant layer resulting in less partitioning and diffusion across the membrane surface. On the other hand, rejections of hydrophobic compounds by NF-90 were not observed to be affected by fouling; however, hydrophilic neutral compounds showed increased rejections by 7-30%.     

Occurrence and fate of bulk organic matter and pharmaceutically active compounds in managed aquifer recharge: a review

Managed aquifer recharge (MAR) is a natural water treatment process that induces surface water to flow in response to a hydraulic gradient through soil/sediment and into a vertical or horizontal well. It is a relatively cost-effective, robust and sustainable technology. Detailed characteristics of bulk organic matter and the occurrence and fate of pharmaceutically active compounds (PhACs) during MAR processes such as bank filtration (BF) and artificial recharge (AR) were reviewed. Understanding the fate of bulk organic matter during BF and AR is an essential step in determining pre- and/or post-treatment requirements. Analysis of organic matter characteristics using a suite of analytical tools suggests that there is a preferential removal of non-humic substances during MAR. Different classes of PhACs were found to behave differently during BF and AR. Antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), beta blockers, and steroid hormones generally exhibited good removal efficiencies, especially for compounds having hydrophobic-neutral characteristics. However, anticonvulsants showed a persistent behavior during soil passage. There were also some redox-dependent PhACs. For example, X-ray contrast agents measured, as adsorbable organic iodine (AOI), and sulfamethoxazole (an antibiotic) degraded more favorably under anoxic conditions compared to oxic conditions. Phenazone-type pharmaceuticals (NSAIDs) exhibited better removal under oxic conditions. The redox transition from oxic to anoxic conditions during soil passage can enhance the removal of PhACs that are sensitive to redox conditions. In general, BF and AR can be included in a multi-barrier treatment system for the removal of PhACs.     

Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: batch and column studies

Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log K_ow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation represents an important mechanism for the removal of PhACs during soil passage.     

Impact of humic acid fouling on membrane performance and transport of pharmaceutically active compounds in forward osmosis

The impact of humic acid fouling on the membrane transport of two pharmaceutically active compounds (PhACs) – namely carbamazepine and sulfamethoxazole – in forward osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was promoted by the complexation with calcium ions in the feed solution and the increase in ionic strength at the membrane surface due to the reverse transport of NaCl draw solute. The increase in the humic acid deposition on the membrane surface led to a substantial decrease in the membrane salt (NaCl) permeability coefficient but did not result in a significant decrease in the membrane pure water permeability coefficient. As the deposition of humic acid increased, the permeation of carbamazepine and sulfamethoxazole decreased, which correlated well with the decrease in the membrane salt (NaCl) permeability coefficient. It is hypothesized that the hydrated humic acid fouling layer hindered solute diffusion through the membrane pore and enhanced solute rejection by steric hindrance, but not the permeation of water molecules. The membrane water and salt (NaCl) permeability coefficients were fully restored by physical cleaning of the membrane, suggesting that humic acid did not penetrate into the membrane pores.     

Influences of solution chemistry and polymeric natural organic matter on the removal of aquatic pharmaceutical residuals by nanofiltration

This study demonstrates the removal efficiency and the permeate flux behavior during cross-flow nanofiltration (NF) of aqueous solutions of five pharmaceutically active compounds (PhACs). Cephalexin, tetracycline, acetaminophen, indomethacin and amoxicillin were used as models of PhACs, and alginate was selected as model of natural organic matter (NOM). Two commercial composite NF membranes (SR2 and SR3) with different characteristics were used. The highest rejection was observed for tetracycline, i.e., 75-95% for membrane SR 2 and 95-100% for membrane SR 3, while the rejection was least for acetaminophen (32-36% for SR2 and 52-59% for SR3). As the pH of acetaminophen solution was increased (from 6 to 9) the rejection would increase. Changes of ionic content (from 10 to 20 mM) lead to increase (from 89 to 93% for SR 3) or decrease (from 100 to 91% for SR2) of cephalexin rejection depending on the membrane used. The permeate flux would decrease with decreasing the pH solution and increasing ionic strength. The addition of alginate in the feed stream decreased the permeate flux, with lower reduction for SR3, and increased the PhAC rejection except for acetaminophen and amoxicillin. Both size and Donnan exclusions seemed to occur, and the effect of Donnan exclusion was more pronounced for the NF membrane having larger effective pore size (SR2).     

A QSAR-like analysis of the adsorption of endocrine disrupting compounds, pharmaceuticals, and personal care products on modified activated carbons

Rapid small-scale column tests (RSSCTs) examined the removal of 29 endocrine disrupting compounds (EDCs) and pharmaceutical/personal care products (PPCPs). The RSSCTs employed three lignite variants: HYDRODARCO 4000 (HD4000), steam-modified HD4000, and methane/steam-modified HD4000. RSSCTs used native Lake Mead, NV water spiked with 100–200 ppt each of 29 EDCs/PPCPs. For the steam and methane/steam variants, breakthrough occurred at 14,000–92,000 bed volumes (BV); and this was 3–4 times more bed volumes than for HD4000. Most EDC/PPCP bed life data were describable by a normalized quantitative structure–activity relationship (i.e. QSAR-like model) of the form:

where TPV is the pore volume, ρ_mc is the apparent density, CV is the molecular volume, C_o is the concentration, ⁸χ_p depicts the molecule's compactness, and FOSA is the molecule's hydrophobic surface area.     

Removal of natural organic matter and THM formation potential by ultra- and nanofiltration of surface water

Natural organic matter (NOM) and trihalomethane formation potential (THMFP) removal were evaluated by ultrafiltration (UF) and nanofiltration (NF). Ten different raw water sources in Alicante province (SE Spain) were analysed. Five types of membranes of different materials were tested with a dead-end-type stirred UF cell. Additional measurements, such as dissolved organic carbon, ultraviolet absorbance (254nm), THMFP, ion concentration, pH, conductivity, etc. were made on raw water, permeates and concentrates. The SUVA value was used to determine the hydrophobicity of the water analysed. The elimination of NOM and THMFP is correlated with the molecular weight (MW) of NOM determined by size exclusion chromatography (SEC). The flux decline trends were correlated with cation concentration. NOM removal by UF is low, which correlates with the average MW determined by SEC with an average value of 922g/mol (between 833 and 1031g/mol). However, the NOM removal obtained with the NF90 and NF270 NF membranes for all water sources is almost complete (90%). THMFP removal is related to hydrophobicity and permeability of membrane. The NFT50 membrane removes almost 100% of the THMFP of more hydrophobic waters.     

Effects of natural organic matter model compounds on the transformation of carbon tetrachloride by chloride green rust

Interest has grown in the use of reactive minerals for natural and engineered transformation of ground water contaminants. This study investigated how the structural properties of 10 model compounds representing natural organic matter (NOM) influenced their adsorption to chloride green rust (GR-Cl), and how this adsorption affected rate constants for transformation of carbon tetrachloride (CT) by GR-Cl. The affinity of benzoic acid, phthalic acid, trimesic acid, pyromellitic acid, and mellitic acid for the GR-Cl surface generally increased in the order of increasing number of carboxylic acid functional groups, increasing acidity of these functional groups, and increasing charge density. For NOM model compounds that had phenolic functional groups (p-hydroxybenzoic acid, α-resorcylic acid, and caffeic acid), the affinity for the GR-Cl surface was greatest for caffeic acid, which had two adjacent phenolic functional groups. Some NOM model compounds had experimentally determined Langmuir maximum adsorption capacities (q_{max−Langmuir}) greater than those calculated based on external surface area measurements and the size of the NOM model compound, suggesting adsorption to internal as well as external sites at the GR-Cl surface for these compounds. Rate constants for CT transformation by GR-Cl generally decreased as the affinity of the NOM model compounds (estimated by Langmuir K values) increased, but there was no statistically significant correlation between Langmuir parameters (i.e., K and q_{max−Langmuir}) and rate constants, perhaps due to significant adsorption of some NOM model compounds to sites that were not accessible to CT, such as interlayer sites. Unlike the other NOM model compounds, caffeic acid, which adsorbed to a significant extent to the GR-Cl surface, increased the rate constant for CT transformation. The influence of NOM on rate constants for CT transformation by green rusts should be considered in ground water remediation planning.     

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.     

Effects of selected pharmaceutically active compounds on treatment performance in sequencing batch reactors mimicking wastewater treatment plants operations

The impact of four pharmaceutically active compounds (PhACs) introduced both individually and in mixtures was ascertained on the performance of laboratory-scale wastewater treatment sequencing batch reactors (SBRs). When introduced individually at concentrations of 0.1, 1 and 10 μM, no significant differences were observed with respect to chemical oxygen demand (COD) and ammonia removal. Microbial community analyses reveal that although similarity index values generally decreased over time with an increase in PhAC concentrations as compared to the controls, no major microbial community shifts were observed for total bacteria and ammonia-oxidizing bacteria (AOB) communities. However, when some PhACs were introduced in mixtures, they were found to both inhibit nitrification and alter AOB community structure. Ammonia removal decreased by up to 45% in the presence of 0.25 μM gemfibrozil and 0.75 μM naproxen. PhAC mixtures did not however affect COD removal performance suggesting that heterotrophic bacteria are more robust to PhACs than AOB. These results highlight that the joint action of PhACs in mixtures may have significantly different effects on nitrification than the individual PhACs. This phenomenon should be further investigated with a wider range of PhACs so that toxicity effects can more accurately be predicted.     

A QSAR model for predicting rejection of emerging contaminants (pharmaceuticals, endocrine disruptors) by nanofiltration membranes

A quantitative structure activity relationship (QSAR) model has been produced for predicting rejection of emerging contaminants (pharmaceuticals, endocrine disruptors, pesticides and other organic compounds) by polyamide nanofiltration (NF) membranes. Principal component analysis, partial least square regression and multiple linear regressions were used to find a general QSAR equation that combines interactions between membrane characteristics, filtration operating conditions and compound properties for predicting rejection. Membrane characteristics related to hydrophobicity (contact angle), salt rejection, and surface charge (zeta potential); compound properties describing hydrophobicity (log K_ow, log D), polarity (dipole moment), and size (molar volume, molecular length, molecular depth, equivalent width, molecular weight); and operating conditions namely flux, pressure, cross flow velocity, back diffusion mass transfer coefficient, hydrodynamic ratio (J_o/k), and recovery were identified as candidate variables for rejection prediction. An experimental database produced by the authors that accounts for 106 rejection cases of emerging contaminants by NF membranes as result of eight experiments with clean and fouled membranes (NF-90, NF-200) was used to produce the QSAR model. Subsequently, using the QSAR model, rejection predictions were made for external experimental databases. Actual rejections were compared against predicted rejections and acceptable R² correlation coefficients were found (0.75 and 0.84) for the best models. Additionally, leave-one-out cross-validation of the models achieved a Q² of 0.72 for internal validation. In conclusion, a unified general QSAR equation was able to predict rejections of emerging contaminants during nanofiltration; moreover the present approach is a basis to continue investigation using multivariate analysis techniques for understanding membrane rejection of organic compounds.     

Occurrence of pharmaceutically active compounds in surface waters of the henares-jarama-tajo river system (madrid, spain) and a potential risk characterization

The Henares-Jarama-Tajo river system is the largest drainage basin in the Province of Madrid, Spain. This area is characterized by the presence of intensive urban and industrial activities influenced by a continental Mediterranean climate with rainfalls presenting substantial fluctuations along the different seasons. This research aimed to monitor seasonal variations in concentrations of 22 pharmaceutically active compounds (PhACs) in this river system and to establish the potential risk of sublethal effects on aquatic organisms. A total of 10 sampling sites were selected along the river system with samples collected in each of the four seasons during a year-round schedule. Most of the PhACs detected were present in sampling sites downstream in the vicinity of the most populated cities (i.e. Madrid, Guadalajara and Alcalá de Henares). Only two PhACs, fluoxetine and paraxantine, were detected in all sites regardless of the season, and showed median (± interquartile range) concentrations of 21.4 (± 31.2) ng L^- 1 and 8.5 (± 5.3) ng L^- 1, respectively. Other PhACs were detected with a frequency > 80% and included, caffeine, diphenylhydantoin, hydrochlorotiazide, ibuprofen, ketoprofen, diclofenac, sulfamethoxazole, atenolol, naproxen, carbamazepine and propanolol. Seasonal variations were observed with the highest concentrations in December and the lowest in September. By combining measured environmental concentrations with toxicity data (either publicly available or obtained experimentally in our laboratory), and by calculating an Maximum Risk Index (MaxRI) that each combination of PhACs should have for non exceeding the risk threshold, a high potential for long-term risk (MaxRI < 10) was estimated for most of the sampling sites and sampling dates. This research allowed the characterization of the potential risk for each of the PhACs to exert sublethal effects on aquatic organisms using acute screening methods, justifying the need for chronic data in order to refine the risk of these compounds to aquatic organisms.     

Toxicity of aluminium in natural waters controlled by type rather than quantity of natural organic matter

Extension of the conditions under which Al toxicity is tested is required. Environmentally representative preparation of waters is used in investigating roles of alginate (AA) and humic acids (HA) in partitioning of Al (0.5 mg L^− 1), subsequent uptake and accumulation by and toxicity to Lymnaea stagnalis. HA and AA did not alter precipitation of Al(OH)₃, but altered subsequent behaviour of Al. High (40 mg L^− 1) HA concentrations, and to a lesser extent AA, prevented settling and availability for benthic grazing but made deposited Al more likely to be ingested. HA detoxified but AA increased toxicity relative to Al alone. Low concentration (4 mg L^− 1) AA and HA do not change partitioning but increase uptake; they both detoxify, but AA less than HA. The study shows OC:Al ratio is critical in predicting Al behaviour in natural waters, also uptake is mediated by snail behaviour, not solely a function of concentration and form of Al. Therefore, predicting Al behaviour will be subject to errors in determining relevant water composition and response of biota to the new speciation. However, with respect to toxicity, rather than other aspects of Al behaviour, different ratios of HA and Al are insignificant compared to whether AA is present rather than HA.     

Reactivity of natural organic matter with aqueous chlorine and bromine

While both aqueous bromine (HOBr/OBr(-)) and chlorine (HOCl/OCl(-)) react with natural organic matter (NOM) during water treatment, limited direct parallel comparison of bromine versus chlorine has been conducted. Experiments with model compounds and natural waters indicated more efficient substitution reactions with bromine than chlorine. Kinetic experiments with NOM isolates with and without pre-ozonation were conducted to obtain second-order rate constants (k) with bromine and chlorine. Two-stage reaction kinetics (rapid initial and slower consumption stages) were observed. Bromine reacted about 10 times faster than chlorine with NOM isolates during both stages. The rapid initial stage reactions were too fast to quantify k values, but qualitative estimates ranged between 500 and 5000 M(-1)s(-1). For the slower second stage k values for bromine were 15 to 167 M(-1)s(-1) over the pH range of 5-11, and lower for chlorine (k = 0.7-5M(-1)s(-1)). Values of k correlated with initial SUVA values of NOM (UVA measured at 254 nm divided by DOC). Based upon UV/VIS and solid-state (13)C-NMR spectroscopy, chlorine addition to a NOM isolate resulted in significant oxidation of aromatic and ketone groups while bromine had significantly less change in spectra. Overall, the improved knowledge that bromine reacts faster and substitutes more efficiently than chlorine will be useful in developing strategies to control disinfection by-product formation during water treatment.     

Removal of natural organic matter by ion exchange

Ion exchange is an effective method for removing humic substances from drinking water supplies. We have explored a range of anion exchangers for removal of natural organic matter (NOM), both as isolated from surface waters and after fractionation into four fractions based on hydrophobic and hydrophilic properties. Resins of open structure and high water content are confirmed as the better performers, being very efficient at removal of any charged material, especially that of smaller molecular size. Quaternary ammonium resins containing polar groups are especially effective. The presence of a neighbouring OH group close to the quaternary nitrogen, heteroatoms in the bridge between the exchange site and the polymer backbone, a secondary amino group as the exchange site, or a low ratio of carbon to quaternary nitrogen is beneficial. A suitable balance of polar and non-polar regions in the resin structure appears to be required. Weakly basic amino groups may have a greater affinity for hydrophilic counter ions than quaternary ammonium groups, but generally there are fewer charged sites in the resin at neutral pH. Nevertheless, weak base resins have NOM uptakes nearly as high as strong base resins of similar water content. Water content was found to be the most important parameter, though the effect was less pronounced for strong base resins. For weak base resins of low charge density a non-electrostatic mechanism involving hydrogen bonding of the undissociated acidic species in the NOM to the unprotonated amino groups on the resins is proposed.     

The effects of dissolved natural organic matter on the adsorption of synthetic organic chemicals by activated carbons and carbon nanotubes

Understanding the influence of natural organic matter (NOM) on synthetic organic contaminant (SOC) adsorption by carbon nanotubes (CNTs) is important for assessing the environmental implications of accidental CNT release and spill to natural waters, and their potential use as adsorbents in engineered systems. In this study, adsorption of two SOCs by three single-walled carbon nanotubes (SWNTs), one multi-walled carbon nanotube (MWNT), a microporous activated carbon fiber (ACF) [i.e., ACF10] and a bimodal porous granular activated carbon (GAC) [i.e., HD4000] was compared in the presence and absence of NOM. The NOM effect was found to depend strongly on the pore size distribution of carbons. Minimal NOM effect occurred on the macroporous MWNT, whereas severe NOM effects were observed on the microporous HD4000 and ACF10. Although the single-solute adsorption capacities of the SWNTs were much lower than those of HD4000, in the presence of NOM the SWNTs exhibited adsorption capacities similar to those of HD4000. Therefore, if released into natural waters, SWNTs can behave like an activated carbon, and will be able to adsorb, carry, and transfer SOCs to other systems. However, from an engineering application perspective, CNTs did not exhibit a major advantage, in terms of adsorption capacities, over the GAC and ACF. The NOM effect was also found to depend on molecular properties of SOCs. NOM competition was more severe on the adsorption of 2-phenylphenol, a nonplanar and hydrophilic SOC, than phenanthrene, a planar and hydrophobic SOC, tested in this study. In terms of surface chemistry, both adsorption affinity to SOCs and NOM effect on SOC adsorption were enhanced with increasing hydrophobicity of the SWNTs.     

Neurotoxic and hepatotoxic cyanotoxins removal by nanofiltration

This study investigates the influence of chemical feed characteristics on nanofiltration performance for cyanotoxins removal, namely the neurotoxic anatoxin-a (alkaloid of 166 g/mol, positively charged) and the hepatotoxic microcystins (cyclic peptides of approximately 1,000 g/mol, negatively charged). Results indicate that NF membranes are an effective barrier against anatoxin-a and microcystins in drinking water. Anatoxin-a and especially microcystins were almost completely removed, regardless of the variations in feed water quality (natural organic matter and competitive toxin), the water recovery rate and the pH values. Anatoxin-a removal was governed by electrostatic interactions and steric hindrance, whereas for microcystins the latter was the main mechanism. In turn, fluxes were significantly impacted by background organics and, especially, inorganics (pH, calcium).     

Occurrence of endocrine disrupting compounds in tissues and body fluids of Belgian dairy cows and its implications for the use of the cow as a model to study endocrine disruption

The reproductive performance of high producing dairy cows has dropped severely throughout the last decades. It has already been suggested that the presence of endocrine disrupting compounds (EDCs) in the environment could be one of the reasons for this declining fertility. Reliable data concerning tissue and body fluid concentrations of these chemicals are thus crucial, but currently only scarcely available. Therefore, we selected dairy cows (≥ 6 years) from diverse locations in Belgium and analysed tissues (liver, adipose tissue, muscle, kidney, and ovaria) and body fluids (serum, follicular fluid, and milk) for their content of potential EDCs, such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). Furthermore, we collected milk and serum samples from high producing dairy cows 2-3 weeks post-partum to verify if the massive lipolysis required to sustain milk production is accompanied with an increase in EDC concentrations in milk and serum.Overall, contamination was very low (median sum PCBs liver: 11.7 ng g⁻¹ lw), with follicular fluid samples showing no detectable contamination. CB 153 was present in each tissue sample. Strong correlations could be found between EDCs in the same tissue. The increased PCB concentrations observed in milk samples from high producing dairy cows could indicate that massive lipolysis can play a role in liberating and thereby increasing EDC concentrations in milk.Because concentrations of the most prevalent EDCs in dairy cow tissues and body fluids are very low, exposure to EDCs can hardly be considered as a major cause of declining fertility in high producing dairy cows in Belgium. As a result of this low contamination and the similarities between the female bovine and human reproductive physiology, in vitro studies based on Belgian dairy cow ovarian follicles can be considered as a valuable model to study the effects of EDCs on human reproduction.     

Occurrence of endocrine disrupting compounds, pharmaceuticals, and personal care products in the Han River (Seoul, South Korea)

The occurrence of 31 selected endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) in Korean surface waters was investigated. The area was selected since there is a lack of information in the Seoul area on the suspected contamination of rivers by micropollutants, although over 99% of drinking water is produced from surface waters in this area that has a population of approximately 15 million inhabitants. Samples were collected from upstream/downstream and effluent-dominated creeks along the Han River, Seoul (South Korea) and analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). Most target compounds were detected in both the Han River samples (63%) and the effluent-dominated creek samples (79%). Iopromide, atenolol, TCPP, TECP, musk ketone, naproxen, DEET, carbamazepine, caffeine, and benzophenone were frequently detected in both river and creek samples, although the mean concentrations in effluent-dominated creek samples (102 ng/L-3745 ng/L) were significantly higher than those in river samples (56 ng/L-1013 ng/L). However, the steroid hormones 17β-estradiol, 17α-ethynylestradiol, progesterone, and testosterone, were not detected (< 1 ng/L) in both the river and creek samples. Numerous target compounds (15) were found to be positively correlated (over 0.8) to the conventional water quality parameters (chemical oxygen demand, biochemical oxygen demand, dissolved organic carbon, and ultraviolet absorbance). Results of this study provide increasing evidence that certain EDCs and PPCPs commonly occur in the Han River as the result of wastewater outfalls.     

Influence of dissolved organic matter on estrone removal by NF membranes and the role of their structures

The influence of different dissolved organic matter (DOM) on the removal of steroid hormone estrone during nanofiltration (NF) processes was investigated. Commercial dextran and humic acid (HA) as well as hydrophobic acid fraction (HpoA) derived from treated effluent were selected as DOM. To better understand the mechanism by which they affect estrone transport across NF membrane, the structural characteristics of DOM were also examined. The experimental results showed that DOM studied displayed obviously diverse impacts on estrone removal by NF membranes. These impacts were found to correlate with the structural characteristics of DOM. The presence of dextran without aromatic ring had little effects on the fate and transport of estrone during NF processes. The addition of HA without phenolic groups but great aromaticity improved estrone adsorption on membrane significantly while the “enhancement effect” on estrone rejection was limited. Moreover, estrone rejection by NF membranes was obviously increased by the presence of HpoA which possesses both phenolic groups and aromaticity. Some of the findings reported may be critically important for understanding the removal mechanism of estrone by NF membrane in real water matrix where various DOM co-present.