Joint Toxicity of Two Phthalates with Waterborne Copper to Daphnia magna and Photobacterium phosphoreum.

Di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) are two widely used phthalates, while Cu(II) is a common valence state of copper. They have been ubiquitously detected in the aquatic environment, but information on their joint toxicity to aquatic organisms is scarce. In this study, we evaluated the combined effects of copper and these two phthalates to Daphnia magna and Photobacterium phosphoreum by quantifying the acute toxicity expressed by the EC50 (the concentration causing 50 % of maximal effect) value. The toxicity order was DEHP + Cu(II) > DBP + Cu(II) > Cu(II) > DEHP > DBP for both test species. Antagonism effects were found in the joint toxicity of Cu(II) combined with DBP or DEHP using the toxic unit method. These findings have important implications in environmental risk assessment for phthalates in the aquatic environment in the presence of heavy metals.

Preparation and in vitro antioxidant activities of 6-amino-6-deoxychitosan and its sulfonated derivatives.

The 6-amino-6-deoxychitosan (NC) and their 2, 6-di-N-sulfonated derivatives were prepared via N-phthaloylation, tosylation, azidation, hydrazinolysis, reduction of azide groups and N-sulfonation, and their structures were systematically characterized by FT-IR, 2D HSQC NMR, XRD, gel permeation chromatography (GPC), and elemental analysis. The 6-amino-6-deoxychitosan showed effect in three selected antioxidant essays, including reducing power, superoxide anion radical scavenging ability, and hydroxyl radical scavenging effect. But the factors affecting each activity were different. The reducing power and the superoxide anion radical scavenging ability of NC were strong and closely related to the amino groups in the molecular chains. Both introducing N-sulfonated groups into NC and the concentration reduction of NC and its sulfonated derivatives decreased these activities. For the superoxide anion radical, the molecular charge property was also a significant influence factor. For the hydroxyl radical, NC only showed weak scavenging activity in a special inverse concentration-dependent manner. However, the incorporation of N-sulfonated groups significantly improved the scavenging activity, and the more N-sulfonated groups, the higher the concentrations, the stronger the activity was. The results could be due to the different conformations of NC and its sulfonated derivatives in aqueous solution.

Antagonistic joint toxicity assessment of two current-use phthalates with waterborne copper in liver of Carassius auratus using biochemical biomarkers.

Di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) are two kinds of widely-used phthalates, whereas Cu (II) is a common valence state of copper. They have been ubiquitously detected in the aquatic environment, but information on their joint toxicity on aquatic organisms is scarce. In this study, we evaluated the combined effects of copper and these two phthalates to the goldfish (Carassius auratus) by detecting the antioxidant responses in liver after exposure for 7 and 21 days. The exposure concentrations were in a range relevant to their levels in the natural aquatic environment. The results indicated that DBP, DEHP and Cu (II) can affect the antioxidant status in fish liver, evidenced by the significant alterations of antioxidant defenses (superoxide dismutase, catalase, glutathione) and malondialdehyde. Antagonistic effects were found in the joint toxicity of Cu (II) and DBP or DEHP using the integrated biomarker response (IBR) index. These findings have important implications in the risk assessments of phthalates mixed with some heavy metals in the aquatic environment.

Hepatic oxidative status and metal homeostasis disturbance of 2-hydroxylated dioxin in ICR mice.

In the present study, the toxic effects of the oral exposure of 2-hydroxylated dioxin (2-HODD) in ICR male mice were examined. The mice were administered different doses (0.2, 2.0 and 20.0mg/kg) of 2-HODD. After 14 days of exposure, the oxidative stress (OS) indicator levels and the essential metal concentrations in the mouse livers were determined. The results showed that the superoxide dismutase (SOD) and the glutathione peroxidase (GPx) activities were increased in the 0.2mg/kg group, whereas they were significantly decreased in the 2.0 and 20.0mg/kg groups. Decreases in the catalase (CAT) activity and the glutathione (GSH) levels, accompanied by increases in the malondialdehyde (MDA) contents, were recorded in all of the 2-HODD-treated groups. The hepatic iron, copper and zinc levels increased in all of the 2-HODD-treated groups. The histological examination of the livers demonstrated swollen cells and inflammation. Dose-dependent changes in both the OS indicators and the hepatic metal levels were observed. In conclusion, a single low dose of 2-HODD significantly perturbed the hepatic OS status and metals homeostasis in the mice.

Subacute oral toxicity of BDE-15, CDE-15, and HODE-15 in ICR male mice: assessing effects on hepatic oxidative stress and metals status and ascertaining the protective role of vitamin E.

The present study examined the effects of oral exposure of 4,4'-dibromodiphenyl ether (BDE-15), 4,4'-dichlorodiphenyl ether (CDE-15), and 4,4'-dihydroxydiphenyl ether (HODE-15) on hepatic oxidative stress (OS) and metal status in Institute of Cancer Research (ICR) male mice. Furthermore, the role of vitamin E in ameliorating potential OS caused by BDE-15, CDE-15, and HODE-15 was investigated. Three groups of mice were exposed to 1.20 mg/kg(body weight)/day of each of the three toxicants for 28 days. Results showed that none of the three toxicants altered growth rates of mice, but significantly increased (P<0.05) relative liver weights and decreased relative kidney weights. Pathological changes including cell swelling, inflammation and vacuolization, and hepatocellular hypertrophy in livers were observed. Significant decreases (P<0.05 and P<0.01) in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activity, and glutathione (GSH) levels, together with increases in malondialdehyde (MDA) content were recorded in all toxicant-treated groups. Hepatic copper levels increased in all toxicant-treated groups. Hepatic zinc levels decreased in the liver of BDE-15-treated mice, whereas they increased in the livers of CDE-15-treated and HODE-15-treated mice. In conclusion, daily exposure to the three toxicants perturbed metal homeostasis and increased OS in mouse liver. Experimental data indicated the hepatic oxidative toxicity of the three toxicants followed the order BDE-15

[Study on the risk assessment method of regional groundwater pollution].

Based on the boundary elements of system risk assessment, the regional groundwater pollution risk assessment index system was preliminarily established, which included: regional groundwater specific vulnerability assessment, the regional pollution sources characteristics assessment and the health risk assessment of regional featured pollutants. The three sub-evaluation systems were coupled with the multi-index comprehensive method, the risk was characterized with the Spatial Analysis of ArcMap, and a new method to evaluate regional groundwater pollution risk that suitable for different parts of natural conditions, different types of pollution was established. Take Changzhou as an example, the risk of shallow groundwater pollution was studied with the new method, and found that the vulnerability index of groundwater in Changzhou is high and distributes unevenly; The distribution of pollution sources is concentrated and has a great impact on groundwater pollution risks; Influenced by the pollutants and pollution sources, the values of health risks are high in the urban area of Changzhou. The pollution risk of shallow groundwater is high and distributes unevenly, and distributes in the north of the line of Anjia-Xuejia-Zhenglu, the center of the city and the southeast, where the human activities are more intense and the pollution sources are intensive.

Life-cycle energy efficiency and environmental impacts of bioethanol production from sweet potato.

Life-cycle assessment (LCA) was used to evaluate the energy efficiency and environmental impacts of sweet potato-based bioethanol production. The scope covered all stages in the life cycle of bioethanol production, including the cultivation and treatment, transport, as well as bioethanol conversion of sweet potato. Results show that the net energy ratio of sweet potato-based bioethanol is 1.48 and the net energy gain is 6.55 MJ/L. Eutrophication is identified as the most significant environmental impact category, followed by acidification, global warming, human toxicity, and photochemical oxidation. Sensitivity analysis reveals that steam consumption during bioethanol conversion exerts the most effect on the results, followed by sweet potato yields and fertilizers input. It is suggested that substituting coal with cleaner energy for steam generation in bioethanol conversion stage and promotion of better management practices in sweet potato cultivation stage could lead to a significant improvement of energy and environmental performance.

Preparation, characterization and in vitro anticoagulant activity of highly sulfated chitosan.

This work is the first to report sulfation of chitosans with different molecular weight (Mw, 51.5-112.4 kDa) via their trimethylsilylated derivatives as the precursors. Different from original chitosan, silylated chitosan was easily sulfated with sulfur trioxide-pyridine complex under homogeneous conditions in DMSO, and highly sulfated products with degree of sulfation (DS) in the range of 1.65-2.46 and Mw in the range of 18.1-54.5 kDa were obtained at 20-40°C. Degradation of chitosan was inevitable in the reaction process. However, the extent of degradation reduced with increasing of degree of trimethylsilylation (DT). The results of UV-vis and fluorescence emission spectra indicated that the chitosan degradation involved elimination reaction. Clotting assays showed that highly sulfated chitosans significantly prolonged activated partial thromboplastin time (APTT) and thrombin time (TT), but not prothrombin time (PT). A high DS (>2.1) value was essential for the anticoagulant activity.

[Simulation on contamination forecast and control of groundwater in a certain hazardous waste landfill].

On the basis of site investigation and data collection of a certain hazardous waste landfill, the groundwater flow and solute transport coupled models were established by applying Visual Modflow software, which was used to conduct a numerical simulation that forecast the transport process of Cr6+ in groundwater and the effects of three control measures (ground-harden, leakage-proof barriers and drainage ditches) of contaminants transport after leachate leakage happened in impermeable layer of the landfill. The results show that the contamination plume of Cr6+ transports with groundwater flow direction, the contamination rang would reach the pool's boundary in 10 years, and the distance of contamination transport is 1 450 m. But the diffusion range of contamination plume would not be obviously expanded between 10 and 20 years. While the ground is hardened, the contamination plume would not reach the pool's boundary in 20 years. When the leakage-proof barrier is set in the bottom of water table aquifer, the concentration of Cr6+ is higher than that the leakage-proof barrier is unset, but the result is just opposite when setting the leakage-proof barrier in the bottom of underlying aquifer. The range of contamination plume is effectively controlled by setting drainage ditches that water discharge is 2 642 m3 x d(-1), which makes the monitoring wells would not be contaminated in 20 years. Moreover, combining the ground-harden with drainage ditches can get the best effect in controlling contaminants diffusion, and meanwhile, the drainage ditches' daily discharge is reduced to 1 878 m3 x d(-1). Therefore, it is suggested that the control measure combining the ground-harden with drainage ditches should apply to prevent contamination diffusion in groundwater when leachate leakage have happened in impermeable layer of the landfill.

Preparation, characterization and anticoagulant activity in vitro of heparin-like 6-carboxylchitin derivative.

A series of heparin-like 6-carboxylchitin derivatives with different N-acetyl group and sulfate group contents were prepared. Their structures were characterized by element analysis, FT-IR, (13)C NMR, and gel permeation chromatography. Their anticoagulant activity in vitro was investigated for human plasma with respect to activated partial thromboplastin time (APTT). The results showed all 6-carboxylchitin derivatives prolonged APTT within the scope of studied degree of sulfation (0.28-1.03) and Mws (4.3-13.7 kDa). Their anticoagulant activity strongly depended on their structures. 3,6-O-sulfated group promoted the anticoagulant activity. Only incorporation of N-sulfated group into deacetylated 6-carboxylchitin could not improve the anticoagulant activity. But, N-sulfated group and O-sulfated group had the synergistic action, and N-sulfated group could promote the anticoagulant activity for the N,O-sulfated chitin derivatives. In addition, acetyl group took a role in the anticoagulant activity, too.

Preparation, characterization and antimicrobial activity of 6-amino-6-deoxychitosan.

6-Amino-6-deoxychitosans with molecular weights from 0.23×104 to 1.41×104 and degree of substitution from 0.85 to 0.96 were prepared via N-phthaloylation, tosylation, azidation, hydrazinolysis and reduction of azide groups. Their structures were characterized by FT-IR, 1H NMR, 13C NMR, gel permeation chromatography (GPC) and elemental analysis. The antimicrobial activities of 6-amino-6-deoxychitosans against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Aspergillus niger were investigated. The results showed that 6-amino-6-deoxychitosans had a wide spectrum of effective antimicrobial activities. Compared with chitosan, 6-amino-6-deoxychitosans had much better antimicrobial activities. Their minimum inhibitory concentrations (MICs) were between 0.025% and 0.1% (w/v) in acetic/sodium acetate solution with different pH from 5.4 to 7.5. 6-Amino-6-deoxychitosans could also inhibit growth of bacteria tested in distilled water under pH 6.6-8.45. The antimicrobial mechanism was complex and the positive charge on the amino groups was not the sole factor resulting in the antimicrobial activities.

Environmental heterogeneity analysis, assessment of trophic state and source identification in Chaohu Lake, China.

INTRODUCTION: Environmental heterogeneous methods were used for analysing data sets of trophic state with 11 parameters measured at 12 different sites at Chaohu Lake for the period 2004 to 2006. The aim of this research was to determine spatial/temporal variations in water quality, to assess trophic state and to identify pollution sources. Protective measures and schemes were proposed to improve water quality in the lake. DISCUSSION: Hierarchical cluster analysis (CA) grouped the 12 sampling sites into two clusters (Eastern Chaohu Lake and Western Chaohu Lake). Temporal CA classified the 12 months into four periods (March-May; June-August; September-November; January, February and December) with a distinct regular seasonal cycle in Eastern Chaohu Lake and four periods (January-April and December; May, July and November; June, September and October; August) with an irregular seasonal cycle in Western Chaohu Lake. Trophic state index analysis showed that Eastern Chaohu Lake was in mesotrophic levels, while Western Chaohu Lake was in eutrophic and hypereutrophic levels. Based on pollutant source statistics data, the dominant pollution sources were identified as domestic sewage and non-point pollution in Eastern Chaohu Lake. Domestic sewage, industrial and non-point sources were contributed to eutrophication in Western Chaohu Lake.

Mechanism of adsorption of anionic dye from aqueous solutions onto organobentonite.

Organobentonite is suggested as potential super-sorbents for the removal of dyes from wastewater. All kinds of organobentonites are synthesized to adsorb dyes; however, the mechanism of the adsorption is still unclear. In this paper, organobentonites were first modified with hexadecyltrimethylammonium bromide at various amounts to reveal the adsorption mechanism. Subsequently, four kinds of organobentonites were utilized to adsorb acid dyes. Results show that the main mechanism of the adsorption of acid dye is an anionic exchange. The counter-ion bromide in the organobentonite was replaced by the dye anion. The study reveals that the adsorption capacity of organobentonite is affected by the surfactant alkyl chain length. When the longer alkyl chain surfactant was modified, bentonite showed higher adsorption capacity. Specific surface areas had no effect on the adsorption. However, the XRD patterns show that interlamellar distance and lamellar distribution have some effects on the adsorption. High adsorption capacity and low residual concentration were obtained by the organobentonite adsorbents. The revelation of the adsorption mechanism makes it possible to obtain more novel and suitable organobentonite adsorbents for anionic dye removal from wastewater.

[Degradation effect and mechanism of 2,4-DNT by reduction-ZPF catalytic oxidation].

ZPF(zeoliteartificial pillared by alpha-FeOOH) which prepared in the laboratory and characterized by FTIR and XRD was used as catalyst, and was tested for its activity in catalytic H2O2, of 2,4-DNT, which is persistent and difficult to be degraded in groundwater. The degradation of 2,4-DNT was examined at different pHs in the reduction, catalytic oxidation and combination technology of reduction-catalytic oxidation reaction systems. Moreover, the removal effect of 2,4-DNT was compared by these three approaches and the catalytic oxidation mechanism was analyzed. The results demonstrated that the removal effect of 2,4-DNT reduced to 2,4-DAT was up to 96.6% in 120 min at pH = 5, which was 1.2, 2.0 times of the rate at pH 7, pH 9 respectively. The catalytic effect was various at different pHs and more significant when the pH close to the zero point of charge of alpha-FeOOH. The order of removal effect of 2,4-DNT at different pHs was pH = 7 > pH = 9 > pH = 5. Compared to single reduction or catalytic oxidation, the removal effect of combination technology was 57.4%, which was evidently improved on the base of 2,4-DNT reduced to 2,4-DAT. The degradation of 2,4-DNT in the presence of ZPF/H2O2 follows a first-order kinetic model and the k(obs) was 0.002 7 min(-1). Due to the concentration of dissolved Fe ion was far less than 0.07 mmol/L, the mechanism was heterogeneous Fenton reaction acting on the surface of the catalyst. Therefore the combination technology was superior to the single treatment of reduction or catalytic oxidation.

Removal of methylene blue by lava adsorption and catalysis oxidation.

Adsorption has been found to be effective for the removal of dyes from effluent; however, the contaminant will cause secondary pollution if it is not properly treated. In this paper, the ability of lava as a low-cost adsorbent and catalyst for the removal of a commercial dye, Methylene Blue (MB), from aqueous solution has been investigated under various experimental conditions. It was found that lava had a high efficiency (more than 98%) for MB removal by adsorption. The adsorption equilibrium data can be fitted well by the Langmuir adsorption isotherm model. The adsorption kinetics was shown to be pseudo-second-order. After adsorption the contaminant could be catalysis oxidized by lava with the aids of H2O2 and ultrasound. The result showed that 95% of the MB could be decomposed in 100 min with the aid of ultrasound at 85 W/cm2. Overall, this study demonstrates lava as a promising material for wastewater treatment to remove and decompose dyes in a single treatment step.