Polycyclic aromatic hydrocarbon (PAH) deposition to and exchange at the air-water interface of Luhu, an urban lake in Guangzhou, China

Urban lakes are vulnerable to the accumulation of semivolatile organic compounds, such as PAHs from wet and dry atmospheric deposition. Little was reported on the seasonal patterns of atmospheric deposition of PAHs under Asian monsoon climate. Bulk (dry + wet) particle deposition, air-water diffusion exchange, and vapour wet deposition of PAHs in a small urban lake in Guangzhou were estimated based on a year-round monitoring. The total PAH particle deposition fluxes observed were 0.44-3.46 μg m⁻² day⁻¹. The mean air-water diffusive exchange flux was 20.7 μg m⁻² day⁻¹. The vapour deposition fluxes of PAHs ranged 0.15-8.26 μg m⁻² day⁻¹. Remarkable seasonal variations of particulate PAH deposition, air-water exchange fluxes and vapour wet deposition were influenced by seasonal changes in meteorological parameters. The deposition fluxes were predominantly controlled by the precipitation intensity in wet season whereas by atmospheric concentration in dry season.     

Biomarker responses and reproductive toxicity of the effluent from a Chinese large sewage treatment plant in Japanese medaka (Oryzias latipes)

The present study was conducted to assess the potential toxicity of the effluent from a large sewage treatment plant (GBD-STP) in Beijing. Japanese medakas (Oryzias latipes) at reproduction active period were exposed to a serial of graded concentrations of the effluent or 100 ng l-1 of 17-alpha-ethinylestradiol (EE2, positive control). Growth, gonadosomatic index (GSI), hepatosomatic index (HSI), reproductive success, induction potency of vitellogenin (VTG) in male fish and that of 7-ethoxyresorufin-o-deethylase activity (EROD) in male fish liver were used as test endpoints. The growth suppression of fish was observed in a dose-dependent manner, resulting in significant differences in both body length and body weight of medaka above 5% effluent. This effluent can inhibit the growth of gonad of medakas and are more sensitive to male than to female. At exposure concentration of 40% and higher, there was an unexpected decrease of HSI values, which may be resulted from sub-lethal toxicity of effluent to fish liver. VTG of plasma in males were induced in all exposure concentration levels, but not in a dose-dependent manner. The concentration of 5% effluent would be the lowest observed adverse effect level (LOAEL) affecting reproductive success when examining fertile individuals, fecundity and fertilization rate. The overt CYP1A response and higher reproductive toxicity may be indicative of low process efficiency of this STP.     

The sedimentation capabilities of hexadecyltrimethylammonium-modified montmorillonites

Natural montmorillonite was modified with a quaternary ammonium compound, hexadecyltrimethylammonium (HDTMA). The sedimentation capabilities of unmodified and modified montmorillonites were then investigated. The sedimentation velocity of modified montmorillonites increased if the amounts of adsorbed HDTMA were from 0.3 to 1.0 times the cation exchange capacitity (CEC). It also emerged that the sedimentation capability of modified montmorillonites was improved and that the variously CEC-modified montmorillonites had similar sedimentation capabilities after they had sorbed organic matter from oily wastewater. Thus, modified montmorillonites (especially 0.5 CEC treatment) had good sedimentation capabilities for sorbing organic substance and can act as carriers in wastewater biotreatment.     

Aging activity of DDE in dissimilar rice soils in a greenhouse experiment

A green-house study was conducted in late 2005 to investigate the aging behavior of p,p'-DDE in two types of soil, Hydragric Anthrosols (An) and Hydragric Acrisols (Ac), according to the World Reference Base (WRB) [FAO/ISRIC/ISSS. 1998. World reference base for soil resources. World soil resources reports, Rome. p. 87]. Paddy rice and dry rice were grown in submerged paddy soils and non-submerged upland soils, respectively. The concentration of extractable p,p'-DDE in fresh DDE-spiked soils was 746.2ngg(-1). During the first few weeks of the experiment, the extractability of p,p'-DDE became increasingly low as the aging period prolonged. However, certain amount of p,p'-DDE that had been captured by soil minerals and organic matter (OM) could be released and became extractable in the later period. The extractability of p,p'-DDE in submerged soils was significantly lower than that in non-submerged soil, because flooding could increase the binding of pollutants to soil particles. The plantation of both dry rice and paddy rice slowed down the aging process of p,p'-DDE. After one month's growth of rice, p,p'-DDE bound to soil particles was released and became extractable. The OM and silt content of An are higher than that of Ac, resulting in more bound residues and relative lower extractability of p,p'-DDE in An. In addition, the extractability of p,p'-DDE could be reduced by the addition of rice straw to soils.     

Non-microcystin producing Microcystis wesenbergii (Komárek) Komárek (Cyanobacteria) representing a main waterbloom-forming species in Chinese waters

It is well known that several morphospecies of Microcystis, such as Microcystis aeruginosa (Kützing) Lemmermann and Microcystis viridis (A. Brown) Lemmermann can produce hepatotoxic microcystins. However, previous studies gave contradictory conclusions about microcystin production of Microcystis wesenbergii (Komárek) Komárek. In the present study, ten Microcystis morphospecies were identified in waterblooms of seven Chinese waterbodies, and Microcystis wesenbergii was shown as the dominant species in these waters. More than 250 single colonies of M. wesenbergii were chosen, under morphological identification, to examine whether M. wesenbergii produce hepatotoxic microcystin by using multiplex PCR for molecular detection of a region (mcyA) of microcystin synthesis genes, and chemical analyses of microcystin content by ELISA and HPLC for 21 isolated strains of M. wesenbergii from these waters were also performed. Both molecular and chemical methods demonstrated that M. wesenbergii from Chinese waters did not produce microcystin.     

环境表现对金融利害攸关者的价值

公司财务表现与环境表现之间的联系日益明显.各公司可以通过促进后者而力求获得资助优势.公司环境表现对金融利害攸关者的价值随资助类型而异,同样也随环境改善的程度和具体细节而异.争取资助的公司,以及政府和非政府组织,应当熟悉不同的金融服务业及其具体需要和问题.     

Sorption of polar and nonpolar aromatic compounds to four surface soils of eastern China

Improved predictions on the fate of organic pollutants in surface environments require a better understanding of the underlying sorption mechanisms that control their uptake by soils. In this study, we monitored sorption of nine aromatic compounds with varying physicochemical properties (hydrophobicity, electron-donor/acceptor ability and polarity), including two polycyclic aromatic hydrocarbons, two chlorobenzenes, two nitroaromatic compounds, dichlobenil, carbaryl and 2,4-dichlorophenol in aqueous suspension of four surface soils of eastern China. The tested soils were characterized with respect to organic carbon (OC) content, black carbon content, mineralogy, morphology and size fraction to assess the role of the diverse soil characteristics in sorption. The results of this study show that not only the solute hydrophobicity and the OC content of soil are important to the retention of organic pollutants, but also the solute molecular structure and the soil nature.     

某些太古界岩石的金含量及其与后生含金石英脉矿床的可能关系

<正> 引言 太古界花岗岩-绿岩地体中的金矿化每年可提供大约200t金。现在世界金年产量大约为1300t。 太古界金矿床包括块状硫化物、古砂矿和条带状铁建造,其中最重要的一类是与石英脉伴生的后生矿化。 在空间上与太古界绿岩有密切关系的含金石英脉,已知在世界范围内都有产出。例如南非的巴伯顿山地、西澳大利亚卡尔古利矿区的戈尔登迈尔以及加拿大苏必利尔构造省的阿比蒂比绿岩带。 直至约25年前,人们乐于用来解释金矿脉     

蠕虫在膜生物反应器和活性污泥法中的污泥减量研究

通过长达345d的中试规模试验,研究比较了蠕虫在膜生物反应器(MBR)和活性污泥法(CAS)的生长状况及其导致的污泥减量效果.CAS中的蠕虫生长状况明显优于MBR的蠕虫生长状况.MBR曝气池中平均蠕虫密度(10条·mg-1)远低于CAS曝气池中平均蠕虫密度(71条·mg-1),并且CAS中蠕虫连续保持高密度(>30条·mg-1)生长达172d.CAS中红斑瓢体虫和仙女虫交替成为优势蠕虫.蠕虫生长对MBR的污泥产率(0 40kg·kg-1)和污泥沉降性能(污泥沉降指数133mL·g-1)影响很小,但却能显著减少CAS的污泥产率(0 17kg·kg-1)和改善污泥沉降性能(污泥沉降指数为60mL·g-1).仙女虫比红斑瓢体虫能更大地减少污泥产量和更好地改善污泥沉降性能.蠕虫生长不影响MBR的COD去除率和出水水质,但却显著影响CAS的COD去除率和出水水质.     

温度对自然金成色影响的实验研究

<正> 自然金的化学成分是其形成条件的最重要的标志。自然材料的研究及实验资料表明,金的成色除取决于溶液中金和银的浓度比以外,还取决于其他许多因素,包括热液温度、氧化还原条件、酸碱条件和热液阴阳离子成分等参数。成矿沉积时的温度条件基本上决定了金银元素的类质同象混溶性和金-银系列矿物的成色。同时,温度还以各种方式影响着不同成分的溶液中各金属元素的沉淀和结晶的动力学特征。目前,解决自然金成分与其沉淀温度相互