U.S. Mussel Watch: 1977–1978 results on trace metals and radionuclides     

Edward D. Goldberg  Minoru Koide  Vern Hodge  A.Russel Flegal  John Martin 《Estuarine, Coastal and Shelf Science》1983,16(1):69-93

The results of the U.S. Mussel Watch Monitoring Program for the period 1976–1978 for trace metals and artificial radionuclides in bivalves are presented. The substances analysed included Ag, Cu, Zn, Cd, Ni, Pb, ²³⁸Pu, ^239+240Pu and ²⁴¹Am. The analyses of organic substances will be presented elsewhere. The concentrations of these substances in the bivalves may reflect upwelling processes, anthropogenic inputs or natural levels. Off the California coast, mussels show markedly elevated Pu and Cd concentrations in coastal areas adjacent to the most intensive upwelling zones. Elevated levels of Pb, for example, are found in organisms living adjacent to highly urbanized places. The general patterns of distribution repeat themselves year after year at a given site. Thus, it is concluded that annual monitoring activities may not be necessary and that a frequency of sampling of several or so years may be more appropriate to identify pollution problems. Finally, national or regional baselines for metal concentrations in bivalves from unpolluted waters are proposed. National baselines for Pb in the west coast mussels of 1·0 parts 10^?6 and for Ag in east coast mussels of 0·05 parts 10^?6 are suggested.  相似文献   

A theory of filament eruptions before the impulsive phase of solar flares     

Jun-Ichi Sakai  Shinji Koide 《Solar physics》1992,137(2):293-306

We present a theory of filament eruption before the impulsive phase of solar flares. We show that the upward motion of the magnetic X-point tracing the filament eruption begins several minutes before the impulsive phase of the flare, where the explosive magnetic reconnection starts at the X-point magnetic field configuration located under the filament. No change occurs in the character of the motion of the X-point during the onset of the explosive magnetic reconnection. The upward speed of the X-point is about 110 km s^-1 at the onset of the impulsive phase. We give an important condition leading to filament eruptions, which relate to the state of the current sheet under the filament, where the magnetic energy can be released.  相似文献   

Depositional history of artificial radionuclides in the Ross Ice Shelf,Antarctica     

Minoru Koide  Robert Michel  Edward D. Goldberg  Michael M. Herron  Chester C. Langway 《Earth and Planetary Science Letters》1979,44(2):205-223

The annual fluxes of artificial radionuclides (²³⁸Pu,^239+240Pu,²⁴¹Am,¹³⁷Cs,⁹⁰Sr and³H) from the atmosphere to the Ross Ice Shelf in Antarctica were determined from measurements in strata dated by²¹⁰Pb. Recognizable sources include the U.S. tests (Mike-Ivy and Castle Hill) in the early 1950s, the U.S.S.R. tests of the early 1960s, the SNAP-9A burnup of 1964 and the French and Chinese tests in the late 1960s and 1970s. There are several problems still awaiting resolution: the differences in atmospheric chemistries of fission products and of transuranics produced in weapons tests and the anomalous fluxes of²³⁸Pu to the ice shelf which do not appear to reflect a one-year stratospheric residence. There is no evidence for a smearing of the fallout record as a consequence of diffusion of these radionuclides in the glacial column.  相似文献   

Th-228/Th-232 and Pb-210 geochronologies in marine and lake sediments     

Minoru Koide  Kenneth W. Bruland  Edward D. Goldberg 《Geochimica et cosmochimica acta》1973,37(5):1171-1187

Two dating techniques, applicable to coastal marine and lacustrine sediments over periods ranging from years to a century, evolve from the natural radioactive series: Th-228/ Th-232 from the Th-232 series and Pb-210 from the U-238 series.There is an excess of Th-228 over and above that supported by the parents Th-232 or Ra-228 in such deposits. The amounts of Th-232-supported and Ra-228-supported Th-228 are similar, indicating that both radium and thorium isotopes are removed from solution in these coastal zones quite rapidly after introduction or formation. The radium isotopes are probably transferred from the overlying waters to the sediments via phytoplankton, where they are reportedly enriched. In the surface levels of the deposits analyzed, there is nearly an order of magnitude more unsupported than supported Th-228. This excess Th-228 can be used both for dating purposes over time periods of the order of a decade and as permissive evidence that the uppermost levels of the deposit were obtained during the coring operation. Preliminary results from several lakes indicate the possibility that Th-228/Th-232 geochronologies are held by their sediments.Average rates of accumulation of lake sediments have been obtained from decreases in Pb-210 activity as a function of depth, although surface layers of the deposits may not have been recovered in the coring operation. Finally, Pb-210 geochronologies have been extended from varved to unvarved marine sediments.  相似文献   

The chemical composition of a Greenland glacier     

Herbert Weiss  Kathe Bertine  Minoru Koide  Edward D. Goldberg 《Geochimica et cosmochimica acta》1975,39(1):1-10

Chemical analyses on water from dated strata of a south Greenland permanent ice sheet revealed that there is a larger amount of sulfate in samples accumulated during the past decade than in those 60 or more years older. This increase is attributed to combustion of fossil fuel. With the exception of mercury, cadmium and possibly copper, the heavy metal distributions in the glacial waters are similar to those in atmospheric dusts. Previously reported higher mercury values in recently deposited strata were not confirmed.  相似文献   

Lead-210 and pollen geochronologies on Lake Superior sediments     

Kenneth W. Bruland  Minoru Koide  Carl Bowser  Louis J. Maher  Edward D. Goldberg 《Quaternary Research》1975,5(1):89-98

Rates of sedimentation in two Lake Superior deposits were determined by both ragweed pollen and ²¹⁰Pb geochronologies. The former yields an average rate over the time since the first appearance of enhanced concentrations of the pollen as a consequence of human settlement. Sedimentation rates derived on these two bases can be brought into accord if the first appearance of ragweed pollen in the sediments was around 1830 and if the sedimentation rates have been uniform over the past century.  相似文献   

K台网简介     

青井  真 《国际地震动态》1999,(5)

前言Ｋ－ＮＥＴ（ＫｙｏｓｈｉｎＮｅｔ）是１９９５年兵库县南部地震后,科学技术厅防灾科学技术研究所在全国１０００个地点（现为１００１个地点）布设的强震仪台网。由于是在全日本以约２５ｋｍ的间隔布设同一规格的加速度型强震仪,故能进行非常均匀的观测。该台网是...  相似文献   

Scavenging of particulate matter in coastal waters     

H. Weiss  M. Koide  K. K. Bertine  E. D. Goldberg   《Marine Chemistry》1991,32(2-4)

The uptake of a suite of 19 metals from coastal seawaters upon both glass and Teflon surfaces reflected primarily the sorption of particulate matter derived from crustal rock weathering. Uptake for all elements was greater in the light than in the dark. Based upon these and earlier results, a new definition of scavenging for environmental systems is proposed.  相似文献   

²⁴¹Pu and²⁴¹Am in sediments from coastal basins off California and Mexico     

Minoru Koide  Edward D. Goldberg  Vernon F. Hodge 《Earth and Planetary Science Letters》1980,48(2):250-256

In sediments deposited in the coastal basins off the western North American continent since the early 1960's, there is more²⁴¹Am activity than one would predict if its presence was solely due to the decay of²⁴¹Pu that was produced during the testing of weapons in 1961–1962 (taken as July 1, 1962 for calculations). This excess can be accounted for by the decay of²⁴¹Pu, if pre-1962 fallout (fallout from the pre-moratorium testing) has been continuously introduced into the recent sediments along with fallout from post-moratorium testing. This hypothesis is supported by the plutonium depth profiles which do not reflect direct fallout from the atmosphere, as characterized by two peaks corresponding to the two major weapons testing periods, but continuously increasing plutonium and americium concentrations from 1954 to 1974. Thus, the nuclides may be coming from a large reservoir that has accumulated and mixed fallout since 1952. Such a concentration gradient for all of the nuclides requires their immobilization in the sediment after deposition.  相似文献   

Marine geochemistry—2: scavenging redux     

Edward D. Goldberg  Minoru Koide  Kathe Bertine  Vern Hodge  Martha Stallard  Darko Martincic  Nevenka Mikac  Marco Branica  Jamal K. Abaychi 《Applied Geochemistry》1988,3(6)

Inorganic surfaces sorb dissolved and particulate phases from seawater onto organic films from a variety of sources. Heavy metals such as Au, Pt, Mn and Cd come to the coatings primarily from particulate phases. This observation confirms a previous finding of this laboratory for the uptake of U, Pu and Po. With depth in the open ocean there are greater contributions from the dissolved phases. Microbial and photochemical processes can enrich surfaces in some metals through reduction reactions. Copper and Mn enrichments in the films are attributed to the photo-reductions of Cu(II) to Cu(I) and manganese oxides to Mn(II), respectively, while the uptake of Mo is a consequence of the reduction, mediated by organisms, of molybdate to Mo(V) or Mo(IV). Cadmium, on the other hand, appears to be bioaccumulated in the films.  相似文献