中国图们江河口湖沼沉积中植硅体古气候变化特征

通过对中国图们江河口湖沼沉积剖面的植硅体组合的分析,划分出该剖面自17.1～2.247 kaB.P.期间的6个植硅体组合带,分别对应冷干-凉湿-冷干-凉湿-温暖-温湿的气候阶段.将分析结果与本剖面Na、K、Ba、Cu、Pb、Fe、Mn分析相对比,发现植硅体对气候湿润程度的反映不如Na、K、Fe敏感,但是比其它指标,如泥炭地发育程度对湿润度的反映,要灵敏得多.区域对比发现,本剖面的植硅体古气候过程存在着区域上的良好响应,对全球变化与区域响应研究起着积极作用.     

Distribution and possible sources of organochlorine residues in sediments of a large urban estuary,Port Jackson,Sydney

Sydney Harbour is surrounded by a large capital city of about four million people and its highly urbanised (86%) catchment supports a substantial industrial base and an extensive transport infrastructure. Large commercial and naval ports occupy the waterway and the harbour is an important recreational area. Surficial sediment in Sydney Harbour contains high concentrations of PCBs, HCB, total chlordane, total DDT, aldrin, dieldrin, heptachlor and heptachlor‐epoxide, but low concentrations of lindane. PCBs, total chlordane, and to a lesser extent dieldrin, are most elevated in sediment in creeks on the southern shores of the harbour suggesting sources within older, highly urbanised/industrialised catchments of western‐central Sydney. There are high concentrations of total DDT and HCB in sediments of the upper harbour and Homebush Bay suggesting that chemical industries on the shores of the estuary in this area are sources of these contaminants. Although no sediment quality guidelines apply in Australia, empirically derived biological effects criteria suggest that sediment over extensive areas of Sydney Harbour may have an adverse impact on biota. Especially of concern are sediments containing high concentrations of chlordane and DDT.     

Mercury in the Tinto-Odiel Estuarine System (Gulf of Cádiz, Spain): Sources and Dispersion

The Tinto and Odiel are small rivers draining one of the largest sulphide deposits in the world. As a result of these deposits and a large industrial complex, the adjacent marine area receives a high amount of metal input. Mercury distribution in the Tinto-Odiel estuary, the Huelva Ría and the Gulf of Cádiz was assessed in water and suspended particulatematter (SPM) and sediments. In the rivers and estuaries, dissolved (HgD)and particulate (HgP) mercury showed wide variations (13 to 200 pM and0.3 to 330 nmol g^-1 respectively) depending on the presence or notof sulphidic waters, phosphogypsum deposits, detrital pyrite and oxyhydroxides.In the Ría, concentrations were lower than 10 pM and 4.5 nmol g^-1 for HgD and HgP respectively. In surface waters of the Gulf of Cádiz, the average HgD concentration (pm standard deviation) was 2.9 pm 0.9 pM, which is similar to that of North Atlantic Central Waters. The surface sediments collected in the rivers, the Ría and the Gulf showed systematically enriched mercury compared to pre-industrial levels. Vertical mercury profiles in dated sediment cores were typical of anthropogenically influenced environments starting in the early Roman age. These distribution features suggest that most of the Hg discharged by the Huelva Ría is trapped in the sediments of the Gulf of Cádiz.     

波浪和潮波作用下黄河口快速沉积海床土非均匀固结试验研究

黄河高含沙量水体在弱潮陆相河口入海,80 %的泥沙在河口附近快速堆积。过去研究发现,黄河三角洲潮滩表层沉积物呈现非均匀固结状态。为了揭示该现象产生的机制,在黄河刁口流路三角洲叶瓣潮坪上,现场取土配置黄河口快速沉积形成的流体状堆积物,研究快速沉积的粉质海床土在波浪和潮波作用下的孔压响应及非均匀固结过程。利用静力触探、十字板剪切试验、孔隙水压力监测等原位测试手段,实时测定快速沉积的海床土强度和孔压变化过程。研究发现,快速沉积的粉质土在自重作用下的固结速度很快,正常固结完成后,强度随时间的发展依然不断增加,沿深度方向出现类似原状土体的固结非均匀现象和似超固结状态;在波浪和潮波作用下快速沉积粉质土孔压沿深度出现非均匀变化,在波浪作用下出现了超静孔压的积累。分析发现,该固结状态和强度沿深度方向非均匀变化是由于土体在潮波及潮波和波浪的联合作用下形成的;潮滩表层土体在波浪荷载长期作用下形成硬壳层。     

Distribution,potential sources and ecological risks of two persistent organic pollutants in the intertidal sediment at the Shuangtaizi Estuary,Bohai Sea of China

Spatial distribution, source apportionment, and potential ecological risks of sixteen polycyclic aromatic hydrocarbons (PAHs) and seven endocrine disrupting compounds (EDCs) in the intertidal sediment at the Shuangtaizi Estuary, Bohai Sea of China were analyzed. Results showed that the total PAH concentrations ranged from 28.79 ng g^? 1 dw to 281.97 ng g^? 1 dw (mean: 115.92 ng g^? 1 dw) and the total EDC concentrations from 0.52 ng g^? 1 dw to 126.73 ng g^? 1 dw (mean: 37.49 ng g^? 1 dw). The distribution pattern for the PAHs was generally different from that of the EDCs possibly due to their distinct sources and n-octanol-/water partition coefficients (K_OW). Qualitative and quantitative analytical results showed that PAH sources were mainly from a mixture of pyrogenic and petrogenic contributions. The higher levels at the southeast of Geligang indicated that the EDC pollutants may have mainly originated from the plastic industry and other chemical plants located along the Liao River. Ecological risk assessment revealed that PAHs exhibited low ecotoxicological effects, whereas EDCs, especially 4-tert-octylphenol and bisphenol A, had high ecological hazard to the estuarine biota.     

非生物因子对底栖动物无齿相手蟹重金属富集量的影响

以长江口滨岸滩地生态系统一种常见的大型底栖动物无齿相手蟹(Sesarma dehaani)为研究对象,分析温度、盐度、重金属间相互作用等几个主要非生物因子对无齿相手蟹积累Cu,Zn,Pb,Cr,Ni的影响。结果表明,夏季无齿相手蟹对Cu,Zn,Cr,Ni的累积量高于其他季节,说明较高的温度有助于动物对重金属元素的吸收;秋季,无齿相手蟹体内的Pb含量与盐度显著负相关;春季,无齿相手蟹体内的Zn含量与盐度负相关;无齿相手蟹体内累积的Zn—Ni,Pb—Cr之间相关显著,二者均呈正相关。     

Geochemistry of arsenic in the Huanghe (Yellow River) and its delta region — A review of available data

Water and suspended sediment samples from the Huanghe and its delta region were analyzed to determine arsenic concentrations. Comparison with the data of previous studies and other world pristine and less disturbed rivers reveals high levels of both dissolved and particulate As in this high turbidity river. Relatively stable distribution along the river course and in delta sediment cores shows that antrhopogenic activities have not altered As concentrations by any significant magnitude since the 1940s. Therefore, high levels of As in the Huanghe should be controlled by natural weathering and lithology. In the estuary, biological removal/regeneration and abiotic events (e.g. remobilization) have been identified to cause the active (non-conservative) As distributions. With the limited data set of the present study, the abiotic and biological contributions cannot be assessed accurately, however.     

Sediment budget-based estimates of trace metal inputs to a Chesapeake estuary

This article evaluates whether a sediment budget for the South River, Maryland, can be coupled with metals data from sediment cores to identify and quantify sources of historic metal inputs to marsh and subtidal sediments along the estuary. Metal inputs to estuarine marsh sediments come from fluvial runoff and atmospheric deposition. Metal inputs to subtidal sediments come from atmospheric deposition, fluvial runoff, coastal erosion, and estuarine waters. The metals budget for the estuary indicates that metal inputs from coastal erosion have remained relatively constant since 1840. Historical variations in metal contents of marsh sediments have probably resulted primarily from increasing atmospheric deposition in this century, but prior to 1900 may reflect changing fluvial sources, atmospheric inputs, or factors not quantified by the budget. Residual Pb, Cu, and Zn in the marsh sediments not accounted for by fluvial inputs was low to moderate in 1840, decreased to near zero circa 1910, and by 1987 had increased to levels that were one to ten times greater than those of 1840. Sources of variability in subtidal cores could not be clearly discerned because of geochemical fluxes, turbulent mixing, and bioturbation within the cores. The sediment-metal budgeting approach appears to be a viable method for delineating metal sources in small, relatively simple estuarine systems like the South River and in systems where recent deposition (for example, prograding marshes) prevents use of deep core analysis to identify background levels of metal. In larger systems or systems with more variable sources of sediment and metal input, however, assumptions and measurement errors in the metal budgeting approach suggest that deep core analysis and normalization techniques are probably preferable for identifying anthropogenic impacts.Field and laboratory research conducted at the Department of Geography, University of Maryland, College Park, Maryland, 20742, USAField and laboratory research conducted at the Marine and Estuarine Environmental Science Program, University of Maryland, College Park, Maryland, 20742, USA