A Chromatographic Approach for High-Precision Eu Isotope Analysis.

Eu isotopes are promising tracers across various scientific domains such as planetary, earth, and marine science, yet their high-precision analysis has been challenging due to the similar geochemical properties of rare earth elements (REEs). In this study, a novel two-column chromatographic approach was developed utilizing AG50W-X12 and TODGA resins to separate Eu effectively from matrix and interfering elements like Ba, Nd, Sm, and Gd, while ensuring high Eu yields (99.4 ± 0.4%, n = 19) and low blanks (<20 pg). The robustness of this method is evidenced by various rock types and different Eu loading masses. The efficient purification of Eu facilitated the establishment of a high-precision calibration technique with standard-sample bracketing (SSB) and internal normalization (Nd). When a Nu Plasma 1700 multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) instrument was employed, repeated purification and analysis of various Geological Reference Materials (GRMs) confirmed that the long-term external precision of δ153/151Eu is better than 0.04‰ (2 standard deviation (2SD)), which represents a 2-5-fold increase in precision compared to previously reported methods. Additionally, the high-precision Eu isotopic compositions of five GRMs, including basalts, andesite, syenite, and marine sediment, were measured. The high-precision Eu isotope techniques presented herein open up new avenues for Eu isotope geochemistry.

Heavy metal pollution recorded in Porites corals from Daya Bay, northern South China Sea.

We examined metal-to-calcium ratios (Fe/Ca, Mn/Ca and Zn/Ca) in the growth bands of two Porites corals from Daya Bay, South China Sea, in order to trace long-term trends in local ambient pollution levels. Although Fe and Mn did not show any obvious increasing trends over 32 years in the period 1976-2007, peak values of Fe/Ca and Mn/Ca occurred in the mid-late 1980s, temporally-coeval with the local construction of a nuclear power station. Furthermore, both corals showed rapid increases in Zn concentrations over the past 14 years (1994-2007), most likely due to increases in domestic and industrial sewage discharge. The Daya Bay corals had higher concentrations of metals than other reported corals from both pristine and seriously polluted locations, suggesting that acute (Fe and Mn) and chronic (Zn) heavy metal contamination has occurred locally over the past approximately 32 years.