Thousands of organic micropollutants and their transformation products occur in water. Although often present at low concentrations, individual compounds contribute to mixture effects. Cell-based bioassays that target health-relevant biological endpoints may therefore complement chemical analysis for water quality assessment. The objective of this study was to evaluate cell-based bioassays for their suitability to benchmark water quality and to assess efficacy of water treatment processes. The selected bioassays cover relevant steps in the toxicity pathways including induction of xenobiotic metabolism, specific and reactive modes of toxic action, activation of adaptive stress response pathways and system responses. Twenty laboratories applied 103 unique in vitro bioassays to a common set of 10 water samples collected in Australia, including wastewater treatment plant effluent, two types of recycled water (reverse osmosis and ozonation/activated carbon filtration), stormwater, surface water, and drinking water. Sixty-five bioassays (63%) showed positive results in at least one sample, typically in wastewater treatment plant effluent, and only five (5%) were positive in the control (ultrapure water). Each water type had a characteristic bioanalytical profile with particular groups of toxicity pathways either consistently responsive or not responsive across test systems. The most responsive health-relevant endpoints were related to xenobiotic metabolism (pregnane X and aryl hydrocarbon receptors), hormone-mediated modes of action (mainly related to the estrogen, glucocorticoid, and antiandrogen activities), reactive modes of action (genotoxicity) and adaptive stress response pathway (oxidative stress response). This study has demonstrated that selected cell-based bioassays are suitable to benchmark water quality and it is recommended to use a purpose-tailored panel of bioassays for routine monitoring.

Incidence and prevalence rates of pSS vary widely around the world. The results help us better understand the global epidemiology of pSS. Large population-based studies combining meticulous case-finding and case-ascertainment strategies are needed.

An Fe-Ce bimetal adsorbent was investigated with X-ray powder diffraction (XRD), transmission electron micrograph (TEM), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS) methods for a better understanding of the effect of surface properties on arsenate (As(V)) adsorption. In the adsorption test, the bimetal oxide adsorbent showed a significantly higher As-(V) adsorption capacity than the referenced Ce and Fe oxides (CeO 2 and Fe 3 O 4 ) prepared by the same procedure and some other arsenate adsorbents reported recently. XRD measurement of the adsorbent demonstrated that the phase of magnetite (Fe 3 O 4 ) disappears gradually with the increasing dosage of Ce 4+ ions until reaching a molar ratio of Ce 4+ to Fe 3+ and Fe 2+ of 0.08:0.2:0.1 (Fe-Ce08 refers to the adsorbent prepared at this ratio), and the phase of CeO 2 begins to appear following a further increase of the Ce dose. Combined with the results of TEM observation, it was assumed that a solid solution of Fe-Ce is formed following the disappearance of the magnetite phase. Occurrence of a characteristic surface hydroxyl group (M-OH, metal surface hydroxyl, 1126 cm -1 ), which showed the highest band intensity in the solid solution state, was confirmed on the bimetal oxide adsorbent by FTIR. Quantificational calculation from the XPS narrow scan results of O(1s) spectra also indicated that the formation of the bimetal Fe-Ce08 was composed of more hydroxyl (30.8%) than was the formation of CeO 2 and Fe 3 O 4 (12.6% and 19.6%). The results of adsorption tests on Fe-Ce08 at different As(V) concentrations indicated that both the integral area of the As-O band at 836 cm -1 and the As(V) adsorption capacity increased almost linearly with the decrease of the integral area of M-OH bands at 1126 cm -1 , proving that the adsorption of As(V) by Fe-Ce08 is mainly realized through the mechanism of quantitative ligand exchange. The atomic ratio of Fe on Fe-Ce08 decreased from 20.1% to 7.7% with the increase of the As atom ratio from 0 to 16% after As(V) adsorption, suggesting that As(V) adsorption might be realized through the replacement of the M-OH group of Fe (Fe-OH) with arsenate. The well splitting of three υ 3 bands at As-O band (836 cm -1 ) of FTIR and the hydroxyl ratio (1.7) of Fe-Ce08 calculated from the XPS results suggested that the diprotonated monodentate complex (SOAsO(OH) 2 ) is possibly dominant on the surface of Fe-Ce08.

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We characterized the bacterial populations in surface water receiving effluent from an oxytetracycline (OTC) production plant. Additional sampling sites included the receiving river water 5 km upstream and 20 km downstream from the discharge point. High levels of OTC were found in the wastewater (WW), and the antibiotic was still detectable in river water downstream (RWD), with undetectable levels in river water upstream (RWU). A total of 341 bacterial strains were isolated using nonselective media, with the majority being identified as Gammaproteobacteria. The MICs were determined for 10 antibiotics representing seven different classes of antibiotics, and the corresponding values were significantly higher for the WW and RWD isolates than for the RWU isolates. Almost all bacteria (97%) from the WW and RWD samples demonstrated multidrug-resistant (MDR) phenotypes, while in RWU samples, these were less frequent (28%). The WW and RWD isolates were analyzed for the presence of 23 tetracycline (tet) resistance genes. The majority of isolates (94.2% and 95.4% in WW and RWD, respectively) harbored the corresponding genes, with tet(A) being the most common (67.0%), followed by tet(W), tet(C), tet(J), tet(L), tet(D), tet(Y), and tet(K) (in the range between 21.0% and 40.6%). Class I integrons were detected in the majority of WW and RWD isolates (97.4% and 86.2%, respectively) but were not associated with the tet genes. We hypothesize that the strong selective pressure imposed by a high concentration of OTC contributes to the wide dissemination of tetracycline resistance genes and other antibiotic resistance genes, possibly through mobile genetic elements.

Natural organic matter (NOM) can affect the performance of water treatment processes, and serves as a main precursor for the formation of disinfection byproduct (DBPs) during chlorination. To minimize such undesirable effects, a better understanding of its structural information and reactivity toward chlorine is necessary. In this study, electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to study the molecular composition of NOM in source water. More than four thousand NOM components were resolved in the sample. NOM molecules with a low degree of oxidation (low O/C ratio) were found to be more reactive toward chlorine than those with high O/C ratio. Totally, 659 one-chlorine containing products and 348 two-chlorine containing products were detected in the chlorinated sample at a high confidence level. The chlorinated products can be arranged into series, which indicate they were originated from precursor compounds in series related by the replacement of CH(4) against oxygen. Of the 1007 chlorine-containing products observed in this study, only 7 molecular formulas can be found in previous studies, showing the distinct difference from previous studies. This study explored the reactivity of NOM toward chlorine on a molecular level, which was previously explained on the level of whole mixtures or fractions of NOM, and the identified chlorinated products may contribute to our knowledge of the unknown total organic halide (TOX).

Photolysis Hydroxyl radicals Kinetics ByproductDegradation mechanism a b s t r a c tThe degradation of four pharmaceutical compounds (PhACs), ibuprofen (IBU), diphenhydramine (DP), phenazone (PZ), and phenytoin (PHT) was investigated via ultraviolet (UV) photolysis and UV/H 2 O 2 process with a low-pressure (LP) UV lamp. For each PhAC tested, direct photolysis quantum yields at 254 nm were found to be ranging from 6.32 Â 10 À2 to 2.79 Â 10 À1 mol E À1 at pH 7. The second-order rate constants of the reaction between the PhACs and OH were determined to be from 4.86 Â 10 9 to 6.67 Â 10 9 M À1 s À1 by using a competition kinetic model which utilized para-chlorobenzoic acid ( pCBA) as a reference IntroductionPharmaceutical compounds (PhACs) are developed and manufactured for specific biological effects, to improve human and animal health care, and livestock farming. PhACs are continuously introduced into the environment and are prevalent at small concentrations (Kolpin et al., 2002), which can affect water quality and potentially impact drinking water supplies, ecosystem and human health (Heberer, 2002b;Roefer et al., 2000;Trussell, 2001). Some of the adverse effects caused by pharmaceutical pollution include aquatic toxicity, resistant development in pathogenic bacteria, genotoxicity, and endocrine disruption (Halling-Sørensen et al., 1998;Kü mmerer, 2004;Sumpter, 1998). The presence of trace pharmaceutical and other xenobiotic compounds in finished drinking water is another public health concern, since little is known about potential chronic health effects associated with long term ingestion of mixtures of these compounds through drinking water (Kü mmerer, 2001;Stackelberg et al., 2004). Thus, it is an emerging issue in environmental science and * Corresponding author. Tel.: þ86 10 62849628; fax: þ86 10 62923541. E-mail address: huchun@rcees.ac.cn (C. Hu).A v a i l a b l e a t w w w . s c i e n c e d i r e c t . w a t e r r e s e a r c h 4 3 ( 2 0 0 9 ) 1 7 6 6 -1 7 7 4

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