Assessment and potential sources of metals in the surface sediments of the Yellow River Delta,Eastern China

The Yellow River Delta is the most intact estuary wetland in China and suffers from great pressure of metals. Seventy-seven surface sediment samples were collected in the delta, and contents of Cu, Pb, Cd, Cr, Zn, Ni, and Mn were analyzed by inductively coupled plasma spectrometry and those of Hg and As by atomic fluorescence spectrometry. The results showed that means of metal contents (ppm, dry weight) were as follows: Hg, 0.04; Cr, 61.72; Cu, 20.97; Zn, 60.73; As, 9.47; Pb, 21.91; Cd, 0.12; Ni, 27.24; and Mn, 540.48. 43.8% of Hg and 14.3% of Cd were from the allogenic source while others from the authigenic source. The results of the geoaccumulation indexes appeared that 6.5% of sites from the estuarine and the Gudao areas were moderately polluted by Hg. All ecological risk index values of Hg and 37.7% of Cd were more than 40, which were the main factors of strongly and moderately potential ecological risks of 37.7% of sites in the delta. High Cd contents may be due to the alkaline conditions of the delta and the unreasonable management of the farmland, while the abnormal distribution of Hg to the wet or dry deposition and the erosion of the seawater. It was suggested to monitor Hg content in the atmosphere of the Yellow River Delta. The results were expected to update the pollution status of metals in the delta and created awareness of preserving the sound condition of the Yellow River Delta.     

Role of illumination intensity in microcystin development using Microcystis aeruginosa as the model algae

Environmental Science and Pollution Research - Microcystis aeruginosa (M. aeruginosa) is one of the most common genera of cyanobacteria in algal blooms. In the present work, the impact of the...     

Genetic diversity and population structure of the invasive plant <Emphasis Type="Italic">Solanum rostratum</Emphasis> in China

The level of genetic diversity of 13 Chinese populations of S. rostratum was investigated using nine microsatellite loci. The genetic diversity of the Weisanlu population in Hebei province was the highest and the Hohhot population was the lowest. The genetic differentiation among the populations was highly significant (P < 0.001). A total of 68.54% of the total genetic variation of population was within populations, and the genetic variation between populations accounted for 31.46%. The long-distance dispersal of its seeds by human transport mainly resulted in the rapid dispersal of S. rostratum in China.     

Cosorption of organic chemicals with different properties: their shared and different sorption sites

Complementary sorption of different chemicals was expected and investigating the relationship between the sorption inhibition of primary sorbate (ΔQ(pri)) and sorption of secondary sorbate (Q(sec)) could provide a new angle to understand coadsorption of different chemicals. This study used bisphenol A (BPA) as the primary adsorbate, sulfamethoxazole (SMX) as the competitor, and carbon nanotubes as model adsorbents to study their complementary and competitive adsorption. At low BPA concentrations, the sorption of SMX (Q(sec)) exceeded BPA sorption inhibition (ΔQ(pri)), indicating that these two chemicals complementarily adsorbed on their respectively preferred sorption sites. At high BPA concentrations, higher ΔQ(pri) was observed in comparison to Q(sec), which may be resulted from different packing efficiencies of the adsorbed SMX and BPA. This study emphasized that both competitive and complementary sorption should be discussed in binary sorption system.     

菱镁矿尾矿制备高活性MgO的性能表征

菱镁矿尾矿经预处理后,在一定条件下制备高活性MgO。使用热重-差热分析仪,分析菱镁矿尾矿的分解温度,应用X射线衍射、SEM分析不同煅烧温度、保温时间对MgO晶体结构的影响,并根据Scherrer公式计算MgO晶粒的尺寸。通过电导率仪测定MgO水化电导率,分析不同条件下的MgO活性,探讨煅烧温度、保温时间、颗粒细度与MgO活性之间的关系。结果发现:煅烧温度在1 050℃,保温时间60 min时,菱镁尾矿完全分解,MgO活性最佳;煅烧温度越高,保温时间越长,MgO的活性越差;MgO颗粒细度越小,活性越高。     

Do vehicular emissions dominate the source of C6–C8 aromatics in the megacity Shanghai of eastern China?

The characteristic ratios of volatile organic compounds(VOCs) to i-pentane, the indicator of vehicular emissions, were employed to apportion the vehicular and non-vehicular contributions to reactive species in urban Shanghai. Two kinds of tunnel experiments, one tunnel with more than 90% light duty gasoline vehicles and the other with more than 60% light duty diesel vehicles, were carried out to study the characteristic ratios of vehicle-related emissions from December 2009 to January 2010. Based on the experiments, the characteristic ratios of C6–C8aromatics to i-pentane of vehicular emissions were 0.53 ± 0.08(benzene), 0.70 ± 0.12(toluene),0.41 ± 0.09(m,p-xylenes), 0.16 ± 0.04(o-xylene), 0.023 ± 0.011(styrene), and 0.15 ± 0.02(ethylbenzene), respectively. The source apportionment results showed that around 23.3% of C6–C8 aromatics in urban Shanghai were from vehicular emissions, which meant that the non-vehicular emissions had more importance. These findings suggested that emission control of non-vehicular sources, i.e. industrial emissions, should also receive attention in addition to the control of vehicle-related emissions in Shanghai. The chemical removal of VOCs during the transport from emissions to the receptor site had a large impact on the apportionment results. Generally, the overestimation of vehicular contributions would occur when the VOC reaction rate constant with OH radicals(k OH) was larger than that of the vehicular indicator, while for species with smaller k OH than the vehicular indicator, the vehicular contribution would be underestimated by the method of characteristic ratios.     

Piriformospora indica confers cadmium tolerance in Nicotiana tabacum

Piriformospora indica, a root-colonizing endophytic fungus of Sebacinales, promotes plant growth and confers resistance against biotic and abiotic stresses. In order to confirm the influence of P. indica on growth, proline, malondialdehyde (MDA), chlorophyll, and cadmium (Cd) amounts in Nicotiana tabacum under Cd stress, hydroponics, pot and field trials were conducted. The results showed that P. indica can store Cd in plant roots and reduce leaf Cd content, reduce the concentration of MDA, and increase the proline and chlorophyll content and the activities of catalase, peroxidase, and superoxide dismutase under hydroponic Cd stress. RT-PCR analysis showed that the relative expression level of genes Gsh2, TaPCS1, oas1, GPX, and Hsp70 in colonized plants was 4.3, 1.4, 2.9, 1.7, and 6.9 fold higher than in un-colonized plants respectively. Cd exposure significantly reduced un-colonized plants'' agronomic traits compared to P. indica-colonized ones. Our results suggested that P. indica can sequester Cd in roots, so that much less cadmium was transported to leaves, and the increased concentrations of antioxidant enzymes, pigments and proline contents, as well as the higher expression of stress-related phytochelatin biosynthesis genes in P. indica-inoculated plants, may also serve to protect N. tabacum plants against oxidative damage, enhancing Cd tolerance.     

对核磁共振成像仪建设项目环境影响评价的研究

核磁共振作为一种分析手段广泛应用于物理、化学、生物、医疗等领域.本文从核磁共振原理出发,分析核磁共振成像仪主要环境影响,结合环评现状,分析环评管理存在的主要问题,结合相关法规条文,查找存在这些问题的主要原因,结合目前核磁共振仪的建设情况和使用条件,从切合实际角度出发,提出核磁共振成像仪建设项目环评管理建议.     

雌二醇短期暴露对非洲爪蟾性腺和输卵管形态及性二态基因表达影响的初步研究

环境雌激素对两栖动物的生殖内分泌干扰作用已引起关注,目前的研究主要集中在长期暴露对性腺分化和发育的影响。以雌二醇(E2,10 nmol·L-1)为模式化合物,以非洲爪蟾为实验动物,6月龄的幼蛙暴露6 d,研究雌激素对性腺和输卵管形态以及性二态性基因表达的影响。结果发现,6 d的E2暴露对精巢和卵巢的形态没有明显影响,但从组织学结构来看对卵和精子的发育有微弱的促进作用。E2能够明显地促进了雌性输卵管的发育,表现为输卵管变粗变弯曲。E2暴露显著抑制精巢和卵巢中性激素合成相关基因cyp11a1、3βHSD、Srd5α、ARO的表达,对cyp17的表达无影响,使脑中LHβ和FSHβ的表达下调;对性别分化和性腺发育相关基因Dax、AR、ERα、TFⅢA、TBPL2的表达均无影响,但能够促进卵巢中Sox3的表达;同时促进脑中Emi2的表达,抑制脑中Dmrt1的表达。因此,输卵管可作为敏感的形态指标,性腺中Srd5α、cyp11a1、3βHSD、ARO、Sox3和脑中LHβ、FSHβ、Dmrt1、Emi2可作为分子指标。以上结果可为后续建立评价化学品对两栖动物雌激素效应的短期试验方法提供参考。     

Potassium ferrate pretreatment promotes short chain fatty acids yield and antibiotics reduction in acidogenic fermentation of sewage sludge

During the acidogenic fermentation converting waste activated sludge (WAS) into short-chain fatty acids (SCFA), hydrolysis of complex organic polymers is a limiting step and the transformation of harmful substances (such as antibiotics) during acidogenic fermentation is unknown. In this study, potassium ferrate (K₂FeO₄) oxidation was used as a pretreatment strategy for WAS acidogenic fermentation to increase the hydrolysis of sludge and destruct the harmful antibiotics. Pretreatment with K₂FeO₄ can effectively increase the SCFA production during acidogenic fermentation and change the distribution of SCFA components. With the dosage of 0.2 g/g TS, the maximum SCFA yield was 4823 mg COD/L, which is 28.3 times that of the control group; acetic acid accounts for more than 90% of the total SCFA. The higher dosage (0.5 g/g TS) can further increase the proportion of acetic acid, but inhibit the overall performance of SCFA production. Apart from the promotion of hydrolysis and acidogenesis, K₂FeO₄ pretreatment can also simultaneously oxidizes and degrades part of the antibiotics in the sludge. When the dosage is 0.5 g/g TS, the degradation efficacy of antibiotics is the most significant, and the contents of ofloxacin, azithromycin, and tetracycline in the sludge are reduced by 69%, 42%, and 50%, respectively. In addition, K₂FeO₄ pretreatment can also promote the release of antibiotics from sludge flocs, which is conducive to the simultaneous degradation of antibiotics in the subsequent biological treatment process.