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ABSTRACT: Sediment cores (∼40–100 cm) were collected at 12 locations in the western Bohai Bay, the Haihe River estuary, the Yongding
River estuary and the Tianjin Harbor, China, during 24–26 July 2007, and analyzed for 7Be and 210Pb activities. Due to localized hydrodynamic patterns and frequent disturbance from dredging activities, steady-state sedimentation
features were not observed in this study. As demonstrated in the 7Be and 210Pb profiles, the temporal and spatial variations of these radionuclides support a non-steady state depositional environment
in the study area. By comparing 7Be and 210Pb inventories in the sediments with those of the atmospheric source, we found that: 1) sediments dredged from the Tianjin
Harbor or eroded from nearby estuarine and coastal areas are retained in the western Bohai Bay for relatively short intervals
(several months), as reflected in the relatively high 7Be inventories in the western Bohai Bay; 2) over the long-term (years to decades), 210Pb inventories in the sediments imply that there is a net on-shore transport of sediments, and the sediments are mass-balanced
in the entire study area. Overall, our results suggest that the sediments are retained in the estuaries and the western Bohai
Bay despite local variability in sediment dynamics and disturbance due to human activities.
KeywordBohai Bay-estuary-sedimentation-sediment transport-radionuclide
Chinese Journal of Oceanology and Limnology 04/2012; 28(3):583-592. · 0.50 Impact Factor
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ABSTRACT: This paper considers the magnetic properties of tidal flat sediments of the Yangtze Estuary and its relationship with particle
size. The results indicate that magnetite of multi-domain (MD)/pseudo-single domain (PSD) in size dominates the magnetic properties
of the samples. In addition to detrital magnetite, spherical magnetic particles are found in the magnetically strongest sediments
near Shidongkou sewage outlet, which are ascribed to the product of industrial pollution. Particle size plays a strong role
on the magnetic properties of the sediments. Magnetic susceptibility (x) and saturation isothermal remanent magnetization (SIRM) are positively correlated with the proportion of the fraction of
8-16 μm. However, magnetic parameters indicating fine-grained ferrimagnetic minerals, e.g. susceptibility of anhysteric remanent
magnetization (X
ARM), are highly correlated with the fine fraction of <4 μm and even the fraction of <32 μm. The results indicate that, whenX is used as a proxy for pollutant content, it is necessary to consider the possible influence of particle size on it. Due
to the significant relationship betweenX
ARM and the fine component proportion,X
ARM can be applied to the normalization of pollutant content for particle size effect.
Science in China Series D Earth Sciences 04/2012; 46(9):954-966. · 1.59 Impact Factor
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ABSTRACT: Twelve sediment cores were collected in July 2007 in open waters of western Bohai Bay, the Port of Tianjin, and the adjacent estuaries of the Haihe and Yongding Rivers. While overall concentrations of trace metals at incremental depths in these cores met the Marine Sediment Quality (GB18668-2002) criteria of China, the magnitude of both metal enrichment factors (EF) and geoaccumulation indices (I(geo)) suggested that pollution with Ag, Cd, Cr, Cu and Zn was occurring in the estuaries and Port. Risk analysis also suggested that Ag and Ni concentrations were sufficiently elevated as to cause adverse biological effects in the study area. Although metal concentrations in western Bohai Bay were of less concern, a positive relationship between EF values and excess (210)Pb activity for several metals suggested that their concentrations were increasing over time.
Journal of Environmental Management 04/2011; 92(4):1185-97. · 3.24 Impact Factor
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ABSTRACT: Surface sediments (0-5 cm) from 59 stations within the Yangtze River intertidal zone (YRIZ) were sampled for metal contamination analysis in April and August 2005. The concentrations ranged (in mg kg(-1) dry weight): Al, 40,803-97,213; Fe, 20,538-49,627; Cd, 0.12-0.75; Cr, 36.9-173; Cu, 6.87-49.7; Mn, 413-1,112; Ni, 17.6-48.0; Pb, 18.3-44.1; and Zn, 47.6-154; respectively. Among the 59 sampling stations, enrichment factors (EF) indicate enrichment of Cd (52 stations), Cr (54 stations), Cu (5 stations), Ni (26 stations), Pb (5 stations) and Zn (5 stations). Geoaccumulation indexes (I(geo)) also suggest individual metal contamination in localized areas. This study indicates that Cd, Cr and Ni enrichment in the YRIZ sediment is widespread whereas Cu, Mn, Pb and Zn enrichment is localized or nonexistent. Factor and cluster analyses indicate that Cd is associated with total organic carbon whereas Cu, Cr, Ni, Pb and Zn have a close association with Mn.
Environmental pollution (Barking, Essex: 1987) 03/2009; 157(5):1533-43. · 3.43 Impact Factor
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EcoHealth 07/2008; 5(2):99-100. · 1.70 Impact Factor
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ABSTRACT: In this study, mineral magnetic, particle size and geochemical analyses were conducted on intertidal sediments from the Yangtze Estuary to examine the feasibility of heavy metal concentrations normalization using magnetic techniques. Susceptibility of Anhysteretic Remanent Magnetization (chiARM), the ratio of chiARM to SIRM (Saturation Isothermal Remanent Magnetization) and susceptibility (chiARM/SIRM and chiARM/chi, respectively), and to a lesser degree, frequency dependent susceptibility (chifd), displayed significant correlations with the fine sediment fraction (<16 microm). The strong relationships between chiARM and heavy metals can be explained by the role of particle size and iron oxides in controlling metal concentrations. This study demonstrates that chiARM can be used to normalize for particle size effects as efficiently as common reference elements such as Al. Furthermore, the rapid and non-destructive nature of mineral magnetic measurement technique means that chiARM has a considerable application value in environmental quality monitoring and related studies.
Environmental Pollution 05/2007; 147(1):238-44. · 3.75 Impact Factor
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ABSTRACT: Three short sediment cores (<20 cm) were collected in the high, middle and low tidal flats in the Yangtze River Estuary near the Southern (Nanqu) Sewage Outlet, one of the three largest sewage outlets in Shanghai, China. All samples were analyzed for Al, Cu, Pb, Zn, 210Pb and 7Be. The 210Pbxs profile shows a non-steady-state sedimentation pattern in the study area and 7Be is only found in the upper 1 cm layer of sediment in high and middle tidal flats. In this study, we found that Cu, Pb and Zn contaminants are present in the upper 20 cm of the tidal flat sediment and, after normalizing with Al, the contamination is more striking in the upper approximately 5 cm sediment. Relationships between the metal (Cu, Pb and Zn) enrichment factor and 210Pbxs activity suggest that contamination increases with time. Factor analyses shows that differences in sediment grain size have insignificant effects on Cu and Pb concentrations, but have some influence on Zn concentration in the study area. This preliminary study shows that urbanization and recent coastal wetland reclamation have had an environmental impact on this area.
Marine Pollution Bulletin 12/2004; 49(11-12):910-5. · 2.50 Impact Factor
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ABSTRACT: In order to investigate the source of Pb within the Yangtze River intertidal zone, studying Pb isotope ratios is a likely approach because the ratios of these Pb isotopes can be used to identify the natural or anthropogenic origin of Pb. In this study, a total of 59 surface sediment samples (< 5 cm) were collected during 2004 and 2005 from 26 sites in the Yangtze River intertidal zone. We measured the total Pb concentrations and Pb isotopes (204Pb, 206Pb, 207Pb and 208Pb) and found that the total Pb concentrations varied from 18.3 to 44.1 mg kg− 1 with an average concentration of 27.3 mg kg− 1. The observed Pb isotope ratios, excluding one station near Shanghai Pudong Airport which is significantly influenced by anthropogenic sources, varied from 18.459 to 18.750 for 206Pb/204Pb, 15.628 to 15.728 for 207Pb/204Pb, and 38.715 to 39.213 for 208Pb/204Pb. This study shows that Pb found within the Yangtze River intertidal zone sediments was mainly from the catchment in the Yangtze River watershed. Significant Pb pollution was not discerned in the Yangtze River intertidal zone. However, Pb contamination in some localized areas was suggested by Pb enrichment factor (EF).
Chemical Geology. 257:257-263.
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ABSTRACT: Variations in the magnetic susceptibility of Chinese loess have been used to indicate pedogenic intensity and therefore past climate across the Chinese Loess Plateau (CLP). However, the relationship between climate and magnetic properties has not been fully resolved, and therefore a study of loess sections distributed over a wider climatic region is timely. In this study, we have investigated a 22.1 m loess section (named the Xiashu Loess) at Dagang, China, by integrating both rock magnetic and geochemical proxies. This loess profile is situated in a modern subtropical climate region with annual mean precipitation and temperature of 1100 mm and 15.4 °C, respectively, and therefore has experienced a stronger weathering intensity due to its lower latitude, higher temperature and rainfall. Geochemical and magnetic evidence indicate the same source area for the Xiashu Loess as for loess in northern China. The magnetic mineral assemblage of the Xiashu Loess is dominated by a higher concentration of superparamagnetic (SP)/single domain (SD) magnetite/maghemite grains in strongly weathered paleosols than in the loess layers, consistent with the production of fine-grained ferrimagnetic minerals during pedogenic processes. Nevertheless, compared to loess in the CLP, the Xiashu Loess shows: 1) reduced contrasts in magnetic susceptibility (χ), Hard Isothermal Remanent Magnetization (HIRM) and remanence of coercivity (Bcr) between loess and paleosols units, which indicates that the loess units have undergone stronger pedogenic alterations; 2) lower peak values of HIRM and χ in paleosols. In addition, the ratios SIRM/χ, χARM/SIRM (where SIRM and χARM are Saturation Isothermal Remanent Magnetization and the susceptibility of Anhysteretic Remanent Magnetization, respectively) and Bcr are found to be significantly correlated with the quotient (CaO⁎ + Na2O + MgO)/TiO2, a geochemical indicator of pedogenic intensity. Overall, it seems that pedogenic processes in the Xiashu Loess lead to a relative increase in fine-grained ferrimagnetic SP/SD grains but depletion of anti-ferromagnetic minerals. Magnetic and geochemical proxies indicate strengthened East Asia summer monsoon during Marine Isotope Stages 13, 11 and 5, which is in good agreement with the records from the CLP and the South China Sea.
Earth and Planetary Science Letters 260:86-97. · 4.18 Impact Factor
