Pulleniatina obliquiloculata shells from 16 core-top samples from the tropical Indo-Pacific Oceans are analyzed for the ratios of boron and cadmium to calcium (B/Ca and Cd/Ca). The B/Ca ratios show a very weak positive relationship with[B(OH)₄^-] and the dissolved carbonate species at the apparent calcification depth of P. obliquiloculata. The boron partition coefficients (K_D) between P. obliquiloculata B/Ca and seawater[B(OH)₄^-]/[HCO₃^-] distribute around 1.1×10^-3-1.3×10^-3 with a mean value of (1.19±0.12)×10^-3, and are significantly related to the nutrient concentration, especially phosphate. The lack of any clear correlation between the P. obliquiloculata B/Ca and seawater carbonate chemical parameters suggests that the physiochemical controls on boron incorporation are masked by the complexity of natural seawater condition. But the significant dependence of K_D on nutrient may likely be explained by a nutrient related growth-rate effect. Cd/Ca of P. obliquiloculata shows significant correlation with seawater phosphate concentration, and its partition coefficients (D_Cd) are significantly related to temperature. A first-principle methodology of P. obliquiloculata B/Ca is applied, with the aid of Cd/Ca as a phosphate proxy and a constraint on K_D, to estimating sea water carbonate chemistry (e.g., pH). The results are fairly promising and allow us to propose the possibility to apply the combination of B/Ca and Cd/Ca proxies (and also Mg/Ca and δ¹⁸O for estimating temperature and salinity) for the paleo-reconstruction of seawater carbonate chemistry.

The impact of several chemical poisons on the Arca granosa absorbing ⁴⁵Ca was studied. The results showed that the absorption of ⁴⁵Ca in the blood and the soft tissue by Arca granosa was inhibited by the inorganic compounds of Cu, Zn, Pd, Cd, Hg and so on, among which the inhibition of Cd was the strongest, next was that of Cu and Hg. But the inhibition of the absorption of ⁴⁵Ca in the shell of Arca granosa was little. The impact of three kinds of energy metabolism inhibitory substances on the absorption of ⁴⁵Ca by the Arca granosa showed that the absorption was an active transfer process.

Sea surface temperature (SST) proxies including B/Ca, Mg/Ca, Sr/Ca, U/Ca and δ¹⁸O were analyzed in the skeleton of a Porites coral collected from the Zhujiang River (Pearl River) Estuary (ZRE). These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral Sr/Ca shows the highest correlation with SST variations (r²=0.59), suggesting Sr/Ca is the most robust SST proxy. In contrast, coral δ¹⁸O (r²=0.46), B/Ca (r²=0.43) and U/Ca (r²=0.41) ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation (r²=0.27) between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.

Isotope dilution mass spectrometry (IDMS) and ultra-clean room approach are successfully used in the determination of Cd, Pb and Zn in seawater and the sample pretreatment of analysis.The precision in the determination of Cd, Pb and Zn in seawater is better than ±3% and the limits of detection are 6×10^-12, 6×10^-11 and 2.4×10^-10 respectively.The effects of sample pretreatment such as filtration and acidification on the results of determination of Cd-Pb and Zn in seawater are disscussed.

The authors have determined the distributions of Ph, Cu and Cd ia surface sediment, acid-soluble fraction and interstitial water of the Changjiang Estuary and analysed the relationship between them and some environmental parameters, finding that there exists a quasi-equilibrium between the interstitial water and the sediment. The distribution of Pb or Cu in both phases it controlled mainly by the adsorptioa-desorption and deposition-solution processes of HFO¹⁾ and org.²⁾ in the sediments, whereas Cd is mainly controlled by the depoahisn-Jolution process of CdS. The sedimentation mechanism of Ph, Cu and Cd in the Changjlang Estuary is preliminarily proposed.

In this paper, a comparison viral made between the two results of determining Pb, Cd, Cu and Zn in seawater by direct current (tripping voltammetry (DCS) with rotating glass carbon electrode and by differential pulse stripping voltammetry (DPS) with hanging mercury drop electrode (HMDE).By DCS, the range of linear calibration curves obtained was 4×10^-3 M-2×10^-7M for Cu, Zn and Cd, and 4×10^-9M-2×10^-3M for Pb.By using DPS, the range of linear calibration curve was as follows:Cu 0.65-1.9 ppb; Pb 1.0-10 ppb; Zn 0.65-2.0 ppb; Cd 0.02-0.14 ppb.It was found that DCS could be used for determining Pb, Cu, Zn in coastal waters, but it is necessary to add gallium ion to it to eliminate the interference of Cu-Zn inter-metallic compound for determining Zn.The DPS is better for determinig Cd.

The forms distribution of Zn, Cd, Pb and Cu in waters of the Northwest Bohai Gulf is investigated by inverse polarography of anti-adsorption physically coated mercury film electrode, the higher content of most forms of trace metals is in polluted estuary water, and unstable Zn and Pb are in anomalous distribution. The average concentrations read ΣZn 20.0μg/l (14.5-36.6 μg/l, ΣCd 0.11μg/l (0.080-0.14μg/l), ΣPb 1.0μg/l (0.58-1.6 μg/l), and ΣCu 5.2μg/l) (2.37-8.43 μg/l) respectively.

A total of 106 surface water samples were collected in the South China Sea during two transects in June and December 1998. The samples were collected with strictly contamination free procedure and trace metals were measured by clean laboratory methods and GFAAS. The mean concentrations for the dissolved fractions are:Cu 0.100 μg/dm³, Pb 0.060 μg/dm³, Zn 0.086 μg/dm³, Cd 0.007 μg/dm³, which is close to the world open ocean's level. The spatial distribution of the trace heavy metals shows higher concentrations in offshore area and lower concentrations in the central in the South China Sea, and the concentrations decrease with the distance from the offshore, which suggests the existence of significant continental shelf input of the trace heavy metals. The correlationship among the elements is better in summer than that in winter. Cu is positively correlated with Cd in both seasons and it is also found for the first time that they are positively correlated with nutrients in the South China Sea surface waters which further indicate the biogeochemical cycle of these elements in the marine environment. The baseline value of Cu, Pb, Zn, Cd in the South China Sea surface waters is obtained through statistical analysis.

In this paper, the samples of sediments collected from five sampling-stations in the river-sea water mixing zone of the Zhujiang Estuary have been determined by the sequencial extraction procedure, anodic stripping voltammetry and atomic emission spectrometry etc. The contents of the heavy metals Zn, Cu, Pb and Cd in the various phases which are dissolvable, ion-exchangeable, combined with carbonates, easily-reducible, reducible, combined with organic matters and sulfides and residue in the sediments, have been obtained.

Planktonic foraminifer Globigerinoides ruber (white) and Trilobatus sacculifer are the most frequently used mixed-layer dwelling species for reconstructing past oceanic environments. Specifically, the Mg/Ca ratios of these two foraminiferal species have been used for reconstructing tropical/subtropical changes in sea surface temperature (SST). However, these two species have different morphotypes, of which the spatial and temporal differences in Mg/Ca ratios and their influencing factors are still unclear. Our objective is to investigate the potential differences between the Mg/Ca ratios of these different morphotypes of G. ruber (white) and T. sacculifer in the western Philippine Sea (WPS) and determine their implications for the reconstruction of SST and upper-ocean structure. Mg/Ca measurements are made on two basic morphotypes of G. ruber (white) [sensu stricto (s.s.) and sensu lato (s.l.)] and T. sacculifer [with (w) and without (w/o) a sac-like final chamber] on samples of Site MD06-3047B from the WPS. Our results reveal that Mg/Ca ratios of different G. ruber morphotypes show consistent differences; and those of T. sacculifer morphotypes show staged variations since MIS 3. It is suggested to select a single morphotype for reconstructing SST changes using the Mg/Ca ratios of G. ruber and T. sacculifer in the WPS. Furthermore, the Mg/Ca ratios between G. ruber s.s. and G. ruber s.l. [Δ(Mg/Ca)_{G.ruber s.s.−s.l.}] downcore MD06-3047B covaries with indexes of summer monsoon. Combining with the core-top results, showing regional variation of differences in the Δ(Mg/Ca)_{G.ruber s.s.−s.l.} over the western tropical Pacific, we propose that Δ(Mg/Ca)_{G.ruber s.s.−s.l.} may tend to reflect summer mixed layer depth.