a b s t r a c tArsenate and arsenite may exist simultaneously in groundwater and have led to a greater risk to human health. In this study, an iron-zirconium (Fe-Zr) binary oxide adsorbent for both arsenate and arsenite removal was prepared by a coprecipitation method. The adsorbent was amorphous with a specific surface area of 339 m 2 /g. It was effective for both As(V) and As(III) removal; the maximum adsorption capacities were 46.1 and 120.0 mg/g at pH 7.0, respectively, much higher than for many reported adsorbents. Both As(V) and As(III) adsorption occurred rapidly and achieved equilibrium within 25 h, which were well fitted by the pseudo-second-order equation. Competitive anions hindered the sorption according to the sequence PO 4 . The ionic strength effect experiment, measurement of zeta potential, and FTIR study indicate that As(V) forms inner-sphere surface complexes, while As(III) forms both inner-and outer-sphere surface complexes at the water/Fe-Zr binary oxide interface. The high uptake capability and good stability of the Fe-Zr binary oxide make it a potentially attractive adsorbent for the removal of both As(V) and As(III) from water.

Arsenate Arsenite Regeneration a b s t r a c tTo obtain a highly efficient and low-cost adsorbent for arsenic removal from water, a novel nanostructured FeeCu binary oxide was synthesized via a facile co-precipitation method.Various techniques including BET surface area measurement, powder XRD, SEM, and XPS were used to characterize the synthetic FeeCu binary oxide. It showed that the oxide was poorly crystalline, 2-line ferrihydrite-like and was aggregated with many nanosized particles. Laboratory experiments were performed to investigate adsorption kinetics, adsorption isotherms, pH adsorption edge and regeneration of spent adsorbent. The results indicated that the FeeCu binary oxide with a Cu: Fe molar ratio of 1:2 had excellent performance in removing both As(V) and As(III) from water, and the maximal adsorption capacities for As(V) and As(III) were 82.7 and 122.3 mg/g at pH 7.0, respectively. The values are favorable, compared to those reported in the literature using other adsorbents. The coexisting sulfate and carbonate had no significant effect on arsenic removal. However, the presence of phosphate obviously inhibited the arsenic removal, especially at high concentrations. Moreover, the FeeCu binary oxide could be readily regenerated using NaOH solution and be repeatedly used. The FeeCu binary oxide could be a promising adsorbent for both As(V) and As(III) removal because of its excellent performance, facile and low-cost synthesis process, and easy regeneration. ª 2013 Elsevier Ltd. All rights reserved. IntroductionArsenic, a ubiquitous element found in the environment, is well-known and extensively concerned with high toxicity and carcinogenicity. It is introduced into the water and groundwater through a combination of natural processes such as weathering reactions, dissolution of minerals and biological activity as well as through anthropogenic activities such as mining, agriculture and manufacturing (Cullen and Reimer, 1989;Smedley and Kinniburgh, 2002 Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate /wa tres w a t e r r e s e a r c h 4 7 ( 2 0 1 3 ) 4 0 2 2 e4 0 3 1 0043-1354/$ e see front matter ª

In this paper, the movement behavior of Daphnia magna was studied as a bio-indicator of organophosphorous pesticide (OP) contamination, using an on-line bio-monitoring method, the Multispecies Freshwater Biomonitor®. A static test of acute toxicity test revealed the 24-h and 48-h LC 50 values (95% confidence limit) for Daphnia magna to be respectively 0.45 μg/l and 0.21 μg/l for dipterex 3.80 μg/l and 0.90 μg/l for malathion, and 1.25 μg/l and 0.38 μg/l for parathion. The behavior strength of Daphnia magna was a sensitive indicator of sublethal OP stress and resulted in significant concentrationresponse relationships for the three OPs. Increasing OP concentration will result in more intensive behavioral responses of Daphnia magna and shorter response time, which could be described by the Stepwise Stress Model (SSM). Therefore movement behavior can be effectively applied in early warning of environment quality by on-line bio-monitoring. The intensive changes in behavior strength of Daphnia magna over a short time follow the SSM concept and can be used as an indicator of early stress response to OP accidental contamination.

Behavior of an organism is affected by exposure to toxic chemicals. However, less has been known about behavioral responses of an organism to stresses of toxic chemicals with different toxic characteristics. In present work, Daphnia magna Straus was exposed to gradient concentrations of deltamethrin, chlorothalonil and nitrofen and the behavioral changes of Daphnia magna under different stress were examined. The results showed that the behavioral responses of Daphnia magna to the tested chemicals were affected in general by exposure concentration, rather than toxic characteristics of the chemicals. The duration of avoidance response (DAR) was in a power regression relationship with the toxic unit (TU), defined as the ratio of exposure concentration of the tested chemical to its LC . DAR was independent of the toxic characteristics of chemicals. However, significant behavior adjustment could be observed after exposure to deltamethrin while only step-by-step decrease in behavior strength could be observed when exposed to chlorothalonil and nitrofen. It was suggested from the observation that avoidance behaviors of Daphnia magna to exposures of chemicals with different toxic characteristics could be similar, while their specific response could be different.

a b s t r a c tIn this study, MnFe 2 O 4 /activated carbon magnetic composites with mass ratio of 1:1, 1:1.5 and 1:2 were synthesized using a simple chemical coprecipitation procedure. A variety of techniques such as X-ray diffractometer, scanning electron microscope, magnetization measurements, BET surface area measurements were used to characterize the structure, morphology and magnetic performance of the prepared composite adsorbents. The results showed that the composites had good magnetic properties, which allowed their convenient magnetic separation from water. Spinel manganese ferrite was found to occur in the magnetic phase and the presence of magnetic particles of MnFe 2 O 4 did not significantly affect the surface area and pore structure of the activated carbon. The magnetic composites were effective for tetracycline (TC) removal from water and the maximal adsorption capacity was 590.5 mmol kg À1 at pH 5.0. The TC adsorption followed pseudo-second-order kinetic model and its removal decreases gradually with an increase in pH value, whereas the removal rate was over 60% even at pH 9.0. The TC adsorption process is endothermic and the increase of temperature is favoring its removal. All these results indicated that the prepared composites had the potential to be used as adsorbents for the removal of TC from water or wastewater.

In this study, avoidance behavior of the freshwater cladoceran Daphnia magna Straus was used as indicator to assess the early stress of accidental organophosphorus pesticide (OP) contamination. The movement behavior was detected by a multi-species biomonitoring system. There was obvious concentration-response relationship between the OP stress and the behavioral response even at sublethal exposure. A rising OP stress resulted in a significant decrease of response time to escape (RTE; p<0.05). In comparison of different OPs, it was found that there was a power regression between RTE and the toxic unit of OPs. Therefore, the avoidance behavior of D. magna was a sensitive indicator of sublethal OP stress, and the power relationship could be used to predict the early warning thresholds of more OPs in the on-line biomonitoring system.

The purpose of this study was to assess gender-related distinction in the performance of Cushing's disease (CD) regarding clinical features, radiological findings, neurological and endocrine status, surgical outcome, and quality of life in Han Chinese. A retrospective study was conducted on 87 patients treated by trans-sphenoidal surgery, between 2006 and 2011, at a single treatment center in Shandong Provincial Hospital, China. Features of CD were compared and quality of life was analyzed between genders. The female-to-male ratio was 2.78: 1. Results showed that men have a younger age of diagnosis (P<0.001), a larger adenoma diameter (P<0.001), and a higher invasion rate (P=0.032) and apoplexy rate (P=0.04) than women. To be specific, compared with women, men are more prone to suffering from osteoporosis, hypokalemia, sexual dysfunction, and hypertension (P < 0.05), have significantly higher preoperative and postoperative (six months after surgery) cortisol levels (P<0.001, P=0.003) and a higher recurrence rate (30.43% vs. 7.81%; P=0.028). No significant differences were seen in the CushingQoL scores between genders. Therefore, male patients with CD need more careful and long-term follow-up than female patients.

No abstract