Historical contamination and sources of organochlorine pesticides in sediment cores from Quanzhou Bay, Southeast China   总被引：8，自引：0，他引：8  

Gong X  Qi S  Wang Y  Julia EB  Lv C 《Marine pollution bulletin》2007,54(9):1434-1440

Three sediment cores were collected from the top to the mouth of Quanzhou Bay, Southeast China, in order to establish sources and historical trends of organochlorine pesticides (OCPs) in the region. The spatial distribution of OCPs in surface sediments implies that Quanzhou Bay received the contamination inputs not only from rivers near the shore, but also from outside the bay. The variation profiles of concentrations clearly showed that OCPs were widely used between 1960s and 1980s in China. A recent increasing trend was found in all cores despite their ban in China in 1983. Different ratios of (DDD+DDE)/DDTs indicated that DDTs at the top of the bay were mainly derived from long-term weather soils, while DDTs near the mouth of the bay were mainly derived from fresh inputs from outside the bay. Higher percentage of gamma-HCH in HCHs deposited after 1990 implies that lindane may have been used recently around Quanzhou Bay.  相似文献   

Copper complexation by fulvic acid affects copper toxicity to the larvae of the polychaete Hydroides elegans   总被引：1，自引：0，他引：1  

Qiu JW  Tang X  Zheng C  Li Y  Huang Y 《Marine environmental research》2007,64(5):563-573

Copper toxicity is influenced by a variety of environmental factors including dissolved organic matter (DOM). We examined the complexation of copper by fulvic acid (FA), one of the major components of DOM, by measuring the decline in labile copper by anodic stripping voltammetrically (ASV). The data were described using a one-site ligand binding model, with a ligand concentration of 0.19micromol site mg(-1) C, and a logK' of 6.2. The model was used to predict labile copper concentration in a bioassay designed to quantify the extent to which Cu-FA complexation affected copper toxicity to the larvae of marine polychaete Hydroides elegans. The toxicity data, when expressed as labile copper concentration causing abnormal development, were independent of FA concentration and could be modeled as a logistic function, with a 48-h EC(50) of 58.9microgl(-1). However, when the data were expressed as a function of total copper concentration, the toxicity was dependent on FA concentration, with a 48-h EC(50) ranging from 55.6microgl(-1) in the no-FA control to 137.4microgl(-1) in the 20mgl(-1) FA treatment. Thus, FA was protective against copper toxicity to the larvae, and such an effect was caused by the reduction in labile copper due to Cu-FA complexation. Our results demonstrate the potential of ASV as a useful tool for predicting metal toxicity to the larvae in coastal environment where DOM plays an important role in complexing metal ions.  相似文献   

Endocrine effects of methoxylated brominated diphenyl ethers in three in vitro models     

Hu W  Liu H  Sun H  Shen O  Wang X  Lam MH  Giesy JP  Zhang X  Yu H 《Marine pollution bulletin》2011,62(11):2356-2361

Methoxylated brominated diphenyl ethers (MeO-BDEs) in aquatic environments have been found to be primarily of natural origin in the marine environment and not from biotransformation of synthetic PBDEs. Two of the eight MeO-PBDEs (2′-MeO-BDE-68 and 6-MeO-BDE-47) that were detected in anchovy from the Yangtze River Delta, were natural products from marine organisms. So 2′-MeO-BDE-68 and 6-MeO-BDE-47 were chosen to study the potential to modulate androgen, estrogen, or thyroid hormone receptor- (AR, ER, ThR) mediated responses by use of reporter gene assays. 2′-MeO-BDE-68 was antiandrogenic at 50 μM, estrogenic at 10 μM and antiestrogenic at 10 and 50 μM (IC₅₀ = 4.88 μM). 2′-MeO-BDE-68 enhanced luciferase expression by 5 nM T3 at 50 μM. 6-MeO-BDE-47 exhibited potent antiandrogenicity at 1 μM and greater (IC₅₀ = 41.8 μM) and possessed estrogenic activity at 10 μM and antiestrogenic activity at 10 and 50 μM (IC₅₀ = 6.02 μM).  相似文献   

Fate and tidal transport of butyltin and mercury compounds in the waters of the tropical Bach Dang Estuary (Haiphong, Vietnam)     

Navarro P  Amouroux D  Thanh ND  Rochelle-Newall E  Ouillon S  Arfi R  Van TC  Mari X  Torréton JP 《Marine pollution bulletin》2012,64(9):1789-1798

In this work, two field campaigns were performed in July 2008 (wet season) and March 2009 (dry season) to produce original data on the concentration, partition and distribution of mercury and butyltin compounds along the tropical Bach Dang Estuary located in North Vietnam (Haiphong, Red River Delta). The results demonstrate that mercury and butyltin speciation in the surface waters of this type of tropical estuary is greatly affected by the drastic changes in the seasonal conditions. During high river discharge in the wet season, there was a large estuarine input of total Hg and tributyltin, while the longer residence time of the waters during the dry season promotes increasing MMHg formation and TBT degradation. Although most of the Hg and TBT is transported into the estuary from upstream sources, tidal cycle measurements demonstrate that this estuary is a significant source of TBT and MMHg during the wet (～3kgTBT/day) and dry (～3gMMHg/day) seasons.  相似文献   

Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures   总被引：6，自引：0，他引：6  

Gao X  Yang Y  Wang C 《Marine pollution bulletin》2012,64(6):1148-1155

Total organic carbon (TOC), total nitrogen (TN) and their δ(13)C and δ(15)N values were determined for 42 surface sediments from coastal Bohai Bay in order to determine the concentration and identify the source of organic matter. The sampling sites covered both the marine region of coastal Bohai Bay and the major rivers it connects with. More abundant TOC and TN in sediments from rivers than from the marine region reflect the situation that most of the terrestrial organic matter is deposited before it meets the sea. The spatial variation in δ(13)C and δ(15)N signatures implies that the input of organic matter from anthropogenic activities has a more significant influence on its distribution than that from natural processes. Taking the area as a whole, surface sediments in the marine region of coastal Bohai Bay are dominated by marine derived organic carbon, which on average accounts for 62±11% of TOC.  相似文献   

Circulation Indices of the Aleutian Low Pressure System: Definitions and Relationships to Climate Anomalies in the Northern Hemisphere     

WANG Panxing  Julian X. L. WANG  ZHI Hai  WANG Yukun  SUN Xiaojuan 《大气科学进展》2012,29(5):1111-1118

In this study, a group of indices were defined regarding intensity (P), area (S) and central position (λ^c, Φ^c) of the Aleutian low (AL) in the Northern Hemisphere in winter, using seasonal and monthly mean height field at 1000-hPa. These indices were calculated over 60 winter seasons from 1948/1949 to 2007/2008 using reanalysis data. Climatic and anomalous characteristics of the AL were analyzed based on these indices and relationships between the AL, and general circulations were explored using correlations between indices P, λ^c, and Pacific SST, as well as Northern Hemisphere temperature and precipitation. The main results are these: (1) AL is the strongest in January, when the center shifts to the south and west of its climatological position, and it is the weakest in December when the center shifts to the north and east. (2) AL intensity (P) is negatively correlated with its longitude (λ^c): a deeper low occurs toward the east and a shallower low occurs toward the west. On a decadal scale, the AL has been persistently strong and has shifted eastward since the 1970s, but reversal signs have been observed in recent years. (3) The AL is stronger and is located toward the east during strong El Nino winters and vice versa during strong La Nina years; this tendency is particularly evident after 1975. The AL is also strongly correlated with SST in the North Pacific. It intensifies and moves eastward with negative SST anomalies, and it weakens and moves westward with positive SST anomalies. (4) Maps of significance correlation between AL intensity and Northern Hemisphere temperature and rainfall resemble the PNA teleconnection pattern in mid-latitudes in the North Pacific and across North America. The AL and the Mongolian High are two permanent atmospheric pressure systems adjacent to each other during boreal winter over the middle and high latitudes in the Northern Hemisphere, but their relationships with the El Nino/La Nina events and with temperature and precipitation in the Northern Hemisphere are significantly different.  相似文献   

3D Numerical Simulation of Tectonic Stress Field and Naturally Fracture System of QING-1 Member in Songliao Basin     

WU Linqiang  LIU Chenglin  ZHANG Tao  X U Jingjing  JIANG Chengzhu 《《地质学报》英文版》2019,93(Z2):321-322

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下地幔的氦化合物—FeO2He     

张宝华  Zhang J  Lv J  Li H  Feng X  Lu C  Redfern S A  Liu H  Chen C  Ma Y 《矿物岩石地球化学通报》2019,(3):615-615

氦(He)元素是地球上的稀有元素之一,宇宙中其含量仅次于氢,但由于其化学惰性不能像氢元素一样与其他元素反应生成稳定的化合物,因此只有少量的地球形成初期保留下来的原始氦气存在于大气中。然而,科学家们发现有氦气从地幔俯冲带喷发出来(比如洛杉矶金施,Newport-Inglewood断层带)。因此推测地幔中可能存在氦的化合物。尽管如此,科学工作者一直未发现含有He元素的矿物,甚至在地幔温度压力下也未合成相关的含有氦元素的化合物。  相似文献   

地球气候—地貌分带的基本原则和方法     

希柳.  X  远久 《国土资源信息化》1996,(7):9-10

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Sublethal effects of contamination on the Mediterranean sponge Crambe crambe: metal accumulation and biological responses     

Cebrian E  Martí R  Uriz JM  Turon X 《Marine pollution bulletin》2003,46(10):1273-1284

The effect of low levels of pollution on the growth, reproduction output, morphology and survival of adult sponges and settlers of the sponge Crambe crambe were examined. We transplanted sponges from a control area to a contaminated site and measured the main environmental variables (chemical and physical) of both sites during the study period. Except some punctual differences in particulate organic matter, silicates, nitrates, and water motion, most environmental variables in the water were similar at both sites during the study months. Mainly copper, lead and OM concentrations in the sediment, and water motion were significantly higher at the polluted site and may be implicated in the biological effects observed: decrease in the percentage of specimens with embryos, increase in shape irregularity and decrease in growth rate. Individuals naturally occurring at the polluted site and those transplanted there for four months accumulated ten times more copper than either untouched or transplant controls. Although lead concentration in sediment did not differ between sites, native specimens from the contaminated site accumulated this metal more than untouched controls. Vanadium concentration also tended to increase in the sponges living at or transplanted to the contaminated site but this difference was not significant. C. crambe is a reliable indicator of metal contamination since it accumulates copper, lead and vanadium in high amounts. At the contaminated site, sponge growth, fecundity and survival were inhibited, whereas sponge irregularity ending in sponge fission was promoted. All these effects may compromise the structure and dynamics of the sponge populations in sheltered, metal-contaminated habitats.  相似文献