Dissolved trace metal distributions in Port Jackson estuary (Sydney Harbour), Australia

Concentrations of dissolved metals (Cd, Cu, Ni, Mn and Zn) were determined for summer and winter, under low-flow conditions in Port Jackson, a microtidal, well-mixed estuary in south-east Australia. Mean concentrations of Cd (0.04+/-0.02 microg/l), Ni (0.86+/-0.40 microg/l), Mn (20.0+/-25 microg/l) and Zn (6.47+/-2.0 microg/l) were below water quality guidelines. Concentrations of Cu (1.68+/-0.37 microg/l), however, slightly exceeded recommended values. Dissolved Ni and Mn behaved mostly conservatively, whereas Cd, Cu and Zn showed mid-estuarine maxima. Peaks in Cd, Cu and Zn concentrations were located in the upper estuary, independent of the salinity and suspended particulate matter loading, and were consistent with anthropogenic inputs of metals in the estuary. Concentrations of dissolved Cu were highest in summer, whereas concentrations of Cd, Ni and Mn were significantly lower in summer than winter (P< or =0.05). The increase in temperature and biological activity during summer explained the seasonal variation. The sequence of log K(d) values (20-30 salinity) was Mn>Zn>Cu>Ni. These results give unique information concerning the contemporaneous distribution of dissolved trace metals in the Port Jackson estuary and they provide a data set against which the long-term contamination may be assessed.     

THE PROCESS AND STRATEGY OF URBANIZATION DEVELOPMENT IN NORTHWEST CHINA

ＴＨＥＰＲＯＣＥＳＳＡＮＤＳＴＲＡＴＥＧＹＯＦＵＲＢＡＮＩＺＡＴＩＯＮＤＥＶＥＬＯＰＭＥＮＴＩＮＮＯＲＴＨＷＥＳＴＣＨＩＮＡＺｈａｎｇＺｈｉｌｉａｎｇ（张志良）（ＰｉｐｕｌａｔｉｏｎＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＬａｎｚｈｏｕＵｎｉｖｅｒｓｉ...     

地球重力场的最新高分辨率模型

利用多颗人造地球卫星轨道数据和最新公布的全球地面及海洋重力资料,借助地球重力场的球谐表达式,建立了１９９６高分辨率的地球重力场模型。     

中国第四纪冰期的探讨

中国第四纪冰期问题,迄今仍然是地质、地理工作者中有争论的问题。李四光教授在他生前广泛的科学活动中,曾坚持不懈地致力于第四纪冰川的研究工作,为建立我国第四纪冰期做出了卓越的贡献。中华人民共和国成立后,第四纪冰川工作在社会主义建设突飞猛进的形势下也获得     

天津地区全新世牡蛎滩的古海洋学意义

据天津地区牡蛎滩的研究,本文确认:在渤海西岸牡蛎滩中,以天津宁河地区所见最为发育;它由长重蛎和近江重蛎2种的尸积群和埋葬群组成。据14C测年可知,它们自中全新世初期即已形成,一直延续到2kaB.P.(14C年代)余。其顶板有程度不同的起伏,即使有河口位置空间移动的影响,其顶板分布范围也仅是在现代天津地区平均低潮线下,故而,它们不能表明海平面波动,由于带状牡蛎滩近EW向分布,表明当时潮汐方向与现代相近。