Demystifying mercury geochemistry in contaminated soil–groundwater systems with complementary mercury stable isotope, concentration, and speciation analyses

A holistic multi-analyses (led by Hg stable isotope analysis), multi-media, multi-site approach to improving contaminated site Hg geochemistry, particularly process tracing.

Assessment of coupled Zn concentration and natural stable isotope analyses of urine as a novel probe of Zn status

Heavier Zn isotope compositions in urine compared to blood serum and an accompanying isotope-concentration trend likely reflects Zn processing in the kidneys in response to bodily Zn requirements.

Studi Karakteristik Air-Tanah di Kawasan Nuklir Pasar Jumat (KNPJ) dengan Metode Hidrokimia dan Isotop Alam

Telah dilakukan penelitian air-tanah di Kawasan Nuklir Pasar Jumat (KNPJ) menggunakan metode hidrokimia dan isotop alam. Penelitian dilakukan dengan mengambil sejumlah sampel air di beberapa kawasan KNPJ dan sekitarnya. Sampel air tersebut kemudian dianalisis konsentrasi kimia airnya (anion-kation) dan konsentrasi isotop alam d2H dan d18O menggunakan alat lasser counter. Analisis kimia air dilakukan menggunakan metode ion kromatografi dan titrasi. Tujuan penelitian ini, yaitu untuk mengetahui karakteristik air-tanah terhadap kemungkinan interaksi dengan air permukaan sekitarnya. Berdasarkan hasil analisis hidrokimia (anion-kation) dan isotop alam (d2H, d18O) menunjukkan bahwa air-tanah dalam masih mencerminkan karakter sebagai air-tanah segar atau freshwater. Air-tanah akuifer dalam juga terindikasi tidak berhubungan dengan air-tanah akuifer dangkal yang berada di atasnya. Air-tanah dangkal, sebagian besar masih menunjukkan karakter air-tanah segar dan sebagian lainnya, yaitu SB-8, SB-9, dan SB-10, air-tanahnya mengalami pertukaran ion dan interaksi dengan air permukaan. Air permukaan untuk SB-8 diperkirakan berasal dari rembesan larutan pupuk tanaman sedangkan untuk SB-9 dan SB-10 air permukaan diperkirakan berasal dari rembesan tanki kotoran (septic tank). Groundwater research has been conducted in Nuclear Area of Pasar Jumat (KNPJ) using hydrochemical data and natural isotopes methods. The research was conducted by taking a number of water samples in some areas of KNPJ and also its surrounding areas. The water samples were then analyzed its hydrochemical concentration (anion-cation) and natural isotope concentration d2H and d18O using lasser counter device. Water chemical analysis was conducted by using ion chromatography and titration methods. The purpose of this research is to know the characteristics of groundwater to the possibility of its interaction with the surrounding surface water. Based on the results of hydrochemical analysis (anion-cation) and natural isotopes (d2H, d18O) indicates that groundwater still reflects the character as fresh groundwater or freshwater. The deep aquifer groundwater is also indicated to be unrelated to groundwater of shallow aquifers located above it. While most shallow groundwater still show the character of fresh groundwater, and some others namely SB-8, SB-9, and SB-10, the groundwater undergo ion exchanges and interact with surface water. Surface water for SB-8 is estimated come from the seepage of the liquid plant fertilizer, whereas for SB-9 and SB-10 surface water is estimated come from septic tank seepage.

The Forgotten Variable: Effects of Sample Preparation and Storage on Geochemistry of Invertebrate Skeletal Carbonate

Standard sample preparation often includes cleaning, bleaching, preservation and storage techniques that may affect temperate invertebrate skeletal carbonate composition and integrity. Here we report on a series of interlinked studies and their key results. Rinsing with tap or deionised water has little detectable effect on sample composition and integrity. Bleaching with sodium hypochlorite, especially at low concentrations and for short times, results in no change in mineralogy or stable isotopes. High concentrations of bleach, and oxidation using H2O2, result in sample dissolution and the leaching of Mg from high-Mg samples. H2O2 has a significant effect on ∂18O stable isotope concentration. Chemical removal of organic material is often not necessary. Ultrasonication of samples results in loss of Mg and skeletal material generally, especially from high-Mg specimens. The combination of ultrasound with bleaching (a common shortcut) is even worse. Roasting of specimens to remove organic carbon causes dramatic changes in composition and cannot be recommended. New studies on the effect of storage in various preservatives and conditions are underway. In order to examine longer-term effects of storage, we have been mining museum collections. This collecting activity is ongoing and we would be glad to hear about material we have missed. Sample preparation and storage can have considerable effect on subsequent chemical investigations, and must form part of research planning, collection management, and sample labelling.

Methodology for preliminary assessment of the radioactivity in natural waters

This article presents the results of a preliminary assessment of the radioactivity of natural waters and the isotope analysis of drinking water. It describes the methods for the radiochemical preparation of water samples, which include concentration of uranium isotopes from water samples, extraction from impeding radionuclides and preparation of electrically countable samples. The results of violation of radioactive equilibrium between the isotopes 234U/238U and the several factors affecting this process in water samples have been obtained. It is clear from the obtained result that 234U isotope concentration in groundwater is higher than that in surface water.