Urinary metabolomic profiling in rats exposed to dietary di(2-ethylhexyl) phthalate (DEHP) using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS)

Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental chemical with widespread nonoccupational human exposure through multiple ways. Although considerable efforts have been invested to investigate mechanisms of DEHP toxicity, the key metabolic biomarkers of DEHP toxicity remain to be identified. The aim of this study was to assess the urinary metabonomics of dietary DEHP in rats using the technique of ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). Fourteen female Wistar rats were divided into two groups and given increasing dietary doses of DEHP for 30 consecutive days. The urinary metabolite profile was studied using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) enabled clusters to be clearly separated. Eleven principal urinary metabolites were identified as contributing to the clusters. The clusters in the positive electrospray ionization (ESI) mode were xanthurenic acid, kynurenic acid, nonate, N6-methyladenosine, and L-isoleucyl-L-proline. The clusters in the negative ESI mode were hippuric acid, tetrahydrocortisol, citric acid, phenylpropionylglycine, cPA(18:2(9Z, 12Z)/0:0), and LysoPC(14:1(9Z)). The urinary metabonomic changes indicated that exposure to dietary DEHP can affect energy-related metabolism, liver and renal function, fatty acid metabolism, and cause DNA damage in rats. The findings of this study on the urinary metabolites and metabolic pathways of DEHP may form the basis for future studies on the mechanisms of toxicity of this commonly found environmental chemical.     

A dynamic modelling of nutrient metabolism in a cyclic activated sludge technology (CAST) for treating low carbon source wastewater

Environmental Science and Pollution Research - A new mathematical model incorporating biopolymer kinetics and the process of the simultaneous storage and growth are established for the treatment of...     

Application of phosphate solubilizing bacteria in immobilization of Pb and Cd in soil

Environmental Science and Pollution Research - In the present study, heavy metal (HM)-tolerant phosphate solubilizing bacteria (PSB) were isolated and their performance during the remediation of Pb...     

Factors influencing adsorption and desorption of trimethoprim on marine sediments: mechanisms and kinetics

Environmental Science and Pollution Research - Adsorption-desorption behavior of ionic antibiotics in natural aquatic environment is complex, especially in coastal or estuary area where influencing...     

Distribution and controls of heavy metals and organic matter in the surface sediments of the Southern Yellow Sea,China

Environmental Science and Pollution Research - Accurate and effective determination of the source of heavy metals is essential for the treatment of marine ecological environments. This article...     

Removal of arsenic(III,V) by a granular Mn-oxide-doped Al oxide adsorbent: surface characterization and performance

In order to remove arsenic (As) from contaminated water, granular Mn-oxide-doped Al oxide (GMAO) was fabricated using the compression method with the addition of organic binder. The analysis results of XRD, SEM, and BET indicated that GMAO was microporous with a large specific surface area of 54.26 m^2/g, and it was formed through the aggregation of massive Al/Mn oxide nanoparticles with an amorphous pattern. EDX, mapping, FTIR, and XPS results showed the uniform distribution of Al/Mn elements and numerous hydroxyl groups on the adsorbent surface. Compression tests indicated a satisfactory mechanical strength of GMAO. Batch adsorption results showed that As(V) adsorption achieved equilibrium faster than As(III), whereas the maximum adsorption capacity of As(III) estimated from the Langmuir isotherm at 25 °C (48.52 mg/g) was greater than that of As(V) (37.94 mg/g). The As removal efficiency could be maintained in a wide pH range of 3~8. The presence of phosphate posed a significant adverse effect on As adsorption due to the competition mechanisms. In contrast, Ca²⁺ and Mg²⁺ could favor As adsorption via cation-bridge involvement. A regeneration method was developed by using sodium hydroxide solution for As elution from saturated adsorbents, which permitted GMAO to keep over 75% of its As adsorption capacity even after five adsorption–regeneration cycles. Column experiments showed that the breakthrough volumes for the treatment of As(III)-spiked and As(V)-spiked water (As concentration = 100 μg/L) were 2224 and 1952, respectively. Overall, GMAO is a potential adsorbent for effectively removing As from As-contaminated groundwater in filter application.

     

Toxicity of sediment cores from Yangtze River estuary to zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) embryos

Toxicity evaluation is an important segment in sediment quality monitoring in order to protect aquatic organisms and human health. The purpose of this study is to assess the toxicity of sediments from three sediment cores in Yangtze River Estuary, China, using the zebrafish (Danio rerio) embryo tests. Fertilized zebrafish eggs were exposed to both whole sediments and sediment organic extracts prepared from collected sediments, in order to provide a comprehensive and realistic insight into the bioavailable toxicity potential of the sediments. As end points, development parameters (mortality, hatching rate, and abnormality) in the developing embryos were recorded during the 96-h exposure. The results showed that some samples increased mortality, inhibited the hatching of embryos, and induced morphological abnormalities. The embryonic toxicities presented serrated changes and irregular distribution with depth, which may be related to hydrodynamic effect and unstable environmental input. However, lethal and sub-lethal effects were more significant at the sub-surface sediments (10～40 cm), which indicated that the pollution is more serious in recent decades.     

Simultaneous separation of apigenin,luteolin and rosmarinic acid from the aerial parts of the copper-tolerant plant Elsholtzia splendens

Elsholtzia splendens is a copper-tolerant plant species which grows on copper deposits in China. The generation of a valuable E. splendens biomass on specific contaminated sites has become one of the promising phytotechnologies. The simultaneous separations of apigenin, luteolin, and rosmarinic acid yielded in the ethyl acetate extracts of the flowering aerial parts was achieved by the use of a macroporous resin, polyamide, and silicagel columns during chromatography. Chemical identification confirmed the structures based on the spectra of FTIR, NMR, and HPLC/ESI-MS. The isolated compounds of purity above 98.3 % were evaluated for their in vitro cytotoxic activities against human cancer cell lines including A549 (non-small lung), A431 (skin), and Bcap37 (breast). Among these compounds, luteolin and apigenin presented the best cytotoxic activities against A549, A431, and Bcap37 cells and, therefore, both could be the valuable products for the post-harvest processing of E. splendens biomass.     

XAFS study of starch-stabilized magnetite nanoparticles and surface speciation of arsenate

It has been shown that starch can effectively stabilize nanoscale magnetite particles, and starch-stabilized magnetite nanoparticles (SMNP) are promising for in situ remediation of arsenic-contaminated soils. However, a molecular level understanding has been lacking. Here, we carried out XAFS studies to bridge this knowledge gap. Fe K-edge XAFS spectra indicated that the Fe-O and Fe-Fe coordination numbers of SMNP were lower than those for bare magnetite particles, and these coordination numbers decreased with increasing starch concentration. The decrease in the average coordination number at elevated stabilizer concentration was attributed to the increase in the surface-to-volume ratio. Arsenic K-edge XAFS spectra indicated that adsorbed arsenate on SMNP consisted primarily of binuclear bidentate (BB) complexes and monodentate mononuclear (MM) complexes. More BB complexes (energetically more favorable) were observed at higher starch concentrations, indicating that SMNP not only offered greater adsorption surface area, but also stronger adsorption affinity toward arsenate.     

固定化斜生栅藻净化畜禽废水中氨氮和磷的影响因素

为探讨Cu2+、p H和流速对固定化斜生栅藻去除畜禽废水中NH+4-N、TP效果的影响,在实验室条件下模拟实际污水处理过程,并采用正交实验方案对结果进行分析。结果表明低质量浓度Cu2+(0~0.05 mg/L)改善藻的净化效果,高质量浓度Cu2+(0.50~5.00 mg/L)抑制藻的净化效果;在p H较高的条件下(p H=9),固定化斜生栅藻的净化效果明显提高;流速对结果没有明显影响。通过正交实验,得出固定化斜生栅藻去除畜禽废水中NH+4-N、TP的优化条件如下:Cu2+质量浓度为0.05 mg/L,p H为9,流速为0.3 m/s。此时NH+4-N去除率为96.11%,TP去除率为97.53%。