River is an important pathway for the biogeochemical cycle of Zn. This study reports Zn concentration and δ66Zn composition for suspended particulate matter (SPM) from Lancang River basin in Southwest China, and explore the impact of natural processes and human activities on Zn cycle. The SPM samples have a much higher average Zn content (162 mg kg-1) than that of the upper crust (67.0 mg kg-1), but it is close to the value of the Pearl River (187 mg kg-1). The enrichment factor (EF) values of Zn in SPM range from 1.08 to 6.88, with an average of 2.15, which does not show significant pollution characteristics. The δ66Zn values in SPM range from -0.67‰ to +0.63‰, with an average of +0.13‰. The δ66Zn values showed positive correlation with Ca/Mg ratios while showed little correlation with Zn contents in SPM. It indicated that anthropogenic sources have limited influence on SPM, and the Zn isotope composition in SPM is more likely to be inherited from the weathered rocks materials and influenced by natural fractionation processes in river water. This result contributes to understanding of the geochemical cycling process of Zn and its environmental effects in water.

Analysis of low-level organic contaminants in complex matrices is essential for monitoring global food safety. However, balancing sample throughput with complex experimental designs and/or sample clean-up to best reduce matrix effects is a constant challenge. Multiple strategies exist to mitigate these effects, with internal standard-based methods such as isotope dilution mass spectrometry (IDMS) being the most advantageous. Here, multiple internal calibration strategies were investigated for the quantification of ochratoxin A (OTA) in wheat samples by liquid chromatography-mass spectrometry (LC-MS). Internal standard-based quantitation methods such as single (ID1MS), double (ID2MS), and quintuple (ID5MS) isotope dilution mass spectrometry, as well as external standard calibration, were explored and compared. A certified reference material (CRM) of OTA in flour, MYCO-1, was used to evaluate the accuracy of each method. External calibration generated results 18-38% lower than the certified value for MYCO-1, largely due to matrix suppression effects. Concurrently, consistently lower OTA mass fractions were obtained for the wheat samples upon quantitation by external calibration as opposed to ID1MS, ID2MS, and ID5MS. All isotope dilution methods produced results that fell within the expected range for MYCO-1 (3.17-4.93 µg/kg), validating their accuracy. However, an average 6% decrease in the OTA mass fraction was observed from results obtained by ID1MS compared to those by ID2MS and ID5MS. Upon scrutiny, these differences were attributed to an isotopic enrichment bias in the isotopically labelled internal standard [13C6]-OTA that was used for ID1MS, the OTAL-1 CRM. The advantages and limitations of each isotopic method are illustrated.

A terpene synthase from Nonomuraea coxensis was identified as (+)-1-epi-cubenol synthase. The enzyme is phylogenetically unrelated to the known enzyme of the same function that is widespread in streptomycetes. Isotopic labelling experiments were performed to unambiguously assign the NMR data and to investigate hydrogen migrations during terpene cyclisations. Epoxidations of (+)-1-epi-cubenol and of the plant derived compounds (-)-cubenol and (-)-1-epi-cubenol confirmed the structure of a natural product isolated from the brown alga Dictyopteris divaricata and allowed to conclude on its absolute configuration. The crystal structures of the epoxides from (+)- and (-)-1-epi-cubenol and the acid catalysed conversion into an isomeric ketone are reported.

The Hg released from coal mining activities can endanger soil ecosystems and pose a risk to human health. Understanding the accumulation characteristics of mercury (Hg) in coal mining soil is important for effectively controlling Hg emissions and developing measures for the prevention and control of Hg contamination. To identify the potential sources of Hg in soils, the Hg concentration and isotopic composition characteristics of raw coal and different topsoil types from the areas surrounding a coal mine were determined in this study. The results showed that Hg in coal mainly exists mainly in the form of inorganic Hg, and Hg has experienced Hg2+ photoreduction prior to incorporating into coal. In addition, the composition of Hg isotopes differed significantly among different topsoil types, and the δ202Hg value of the farmland soil exhibited large negative excursions compared to the coal mining soil. The ternary mixed model further revealed the presence of substantial differences in potential Hg sources among the two regions, with the coal mining soil being greatly disturbed by anthropogenic activity, and the relative contributions of Hg from raw coal, coal gangue, and background soil to coal mining soil being 33.42%, 34.4%, and 32.19%, respectively. However, Hg from raw coal, coal gangue and background soil contributed 17.04%, 21.46%, and 61.51% of the Hg in the farmland soil, indicating that the accumulation of Hg in farmland soil was derived primarily from the background soil. Our study demonstrated that secondary pollution in soil caused by immense accumulation of solid waste (gangue) by mining activities offers a significant challenge to ecological security. These findings provide new insights into controlling soil Hg in mining areas and further highlight the urgency of strict protective measures for contaminated sites.

The increase in groundwater salinity of the two major dumpsites in Sierra Leone has been a major concern for stakeholders. Therefore, this study employed geochemical and stable water isotope analyses to investigate the factors controlling groundwater salinity. The proportional sources of the groundwaters were also evaluated using the Bayesian isotope mixing model. The geochemical analysis showed that the groundwater chemistry in the Granvillebrook dumpsite is controlled by water-rock interaction and evaporation while that of the Kingtom is dominated by water-rock interaction and precipitation. The biplot of deuterium (δ2H) versus oxygen (δ18O) composition relative to the global meteoric water line confirms that the groundwaters of the study areas are of meteoric origin. The linear plot of electrical conductivity versus δ18O depicts that mineralization is the major factor impacting the groundwater salinity in the study areas. The stable isotope mixing model in R (SIMMR) suggests that 96.5% of the groundwaters in the study areas are recharged by precipitation while only 3.5% originated from surface water. The SIMMR model also depicts that groundwaters in the Granvillebrook dumpsite have been bridged by leachate (33.0%) and domestic wastewater (15.2%) while for the Kingtom dumpsite, 13% and 21.5% are contaminated by leachate and domestic wastewaters. Contrary to other previous studies, this research confirms the feasibility of using the Bayesian isotope mixing model to quantify the factors influencing groundwater salinity.

So far, no 87 Sr/86 Sr mobility studies have been done for Neolithic remains from Belgium and information on the Sr isotopic variability in the region is scarce. This study aims to explore mobility in a Final Neolithic population from the funerary cave \'Grotte de La Faucille\', contribute to the understanding of the isotopic composition of bioavailable Sr in Belgium, assess evidence for male mobility using proteomic analysis, and explore possible places of origin for nonlocal individuals.
The 87 Sr/86 Sr isotope ratio of dental enamel from six adults and six juveniles was determined. Liquid chromatography mass spectrometry-based protein analysis was employed to identify individuals of male biological sex. 87 Sr/86 Sr of micromammal teeth, snail shells, and modern plants from three geological areas in Belgium were measured to establish isotopic signatures for bioavailable strontium. Nonlocality was assessed by comparing human 87 Sr/86 Sr isotope ratios to the 87 Sr/86 Sr range for bioavailable Sr.
Four individuals yielded 87 Sr/86 Sr isotope ratios consistent with a nonlocal origin. No statistical differences were found between adults and juveniles. Three males were detected in the sample set, of which two show nonlocal 87 Sr/86 Sr values.
This study provides evidence for mobility in Final Neolithic Belgium. The four nonlocal 87 Sr/86 Sr signatures correspond with the 87 Sr/86 Sr of bio-available Sr in Dutch South Limburg, the Black Forest in Southwest Germany, and regions of France, such as parts of the Paris Basin and the Vosges. The results support the ruling hypothesis of connections with Northern France, brought to light by archeological research.

Patagonian aquatic environments have been invaded since the end of the last century by different species of salmonids. Knowing the natal origin and homing/straying rate of the salmonids in colonised environments is essential to understanding the dispersal mechanisms and developing management plans. In the last two decades, Chinook salmon Oncorhynchus tshawytscha showed the greatest natural dispersal capacity in Patagonia. The main goal of this study was to evaluate the environmental strontium isotope ratio (87Sr/86Sr) as a potential natural tag to infer the natal origin and ontogenetic habitat use of salmonids in Patagonia, specifically Chinook salmon. 87Sr/86Sr ratio was determined in water samples from 26 sites distributed in 14 Atlantic and Pacific basins in low and high water seasons. Environmental 87Sr/86Sr showed greater spatial than temporal variation, revealing great potential as a tool to infer the natal origin and life history of several migratory fish species in Patagonia. Otolith core-to-edge 87Sr/86Sr profiles were also analysed in 108 Chinook salmon from six basins. A cluster analysis based on the Unweighted Pair Group method (UPGMA) and Euclidean distances without prior classification grouped the sampled rivers into five main groups with significantly different (p < 0.05) isotopic ratios, sometimes integrated basins with different slopes (Atlantic or Pacific). The cluster analysis based on the natal 87Sr/86Sr period in otolith (∼natal origin) showed clear segregation between the Atlantic and Pacific samples. A mismatch between water and otolith natal 87Sr/86Sr ratio was detected in some Atlantic basins (e.g. De las Vueltas River in Santa Cruz Basin) and Pacific (e.g. Liquiñe Basin) and, which could be explained either by straying behaviours or by large geochemical variability between tributaries, within river systems. Our results showed that 87Sr/86Sr is a useful natural tag to trace the life history of migratory fishes in Patagonia, especially for invasive species such as Chinook salmon.

Pyrite is a typical sulfide mineral which contains various potentially toxic metal(loid)s (PTMs). The pyrite smelting and subsequent industrial utilization activities usually release numerous amounts of PTMs into nearby ecosystem, which may be enriched in the nearby farmland soils and crops, leading to hidden but irreversible harm to human health via the food chain. Herein, the distribution pattern, source apportionment, and potential health risks of Pb, Zn, Cu, Cd and multiple seldom monitored PTMs (Ag, Bi, Sb, Sr, Th, U, W, and V) in the paddy soils and different organs of the rice plants from ten various sites in a typical industrial zone were investigated, where pyrite ores were used for the production of sulfuric acid and subsequent cement over several decades. The results showed that the contents of Cd, Pb and Zn in studied paddy soils generally exceeded the maximum permissible level (MPL) in China, and the contents of Sb and V were approaching the MPL. Moreover, the rice is easier to bioaccumulate Cd, Cu, and Zn than the other studied elements. The hazard quotient (HQ) calculations indicate that the rice containing such multiple elements may cause a high potential non-carcinogenic and carcinogenic health risk for residents, particularly for the senior group. The Pb isotope tracing method combined with PCA (principal component analysis) further uncovered that the pyrite industrial utilization contributed 18.58-55.41 % to the highly enriched PTMs in paddy soils. All these findings indicate that the paddy soil system has been contaminated by the pyrite industrial activities and certain distances or areas should be rigidly forbidden from rice cultivation in the proximity of the pyrite smelting and related industrial sites.

8-iso-prostaglandin F2α is a biomarker of lipid peroxidation, and one of the most commonly used measures of oxidative stress. It is an established biomarker of lung cancer risk. It is commonly measured by enzyme-linked immunosorbent assay. Given its importance, we developed a stable isotope dilution UPLC-tandem mass spectrometric method for the rapid determination of 8-isoprostane in blood.
We tested the discriminatory capability of the method in 49 lung cancer patients, 55 benign lung nodule patients detected by chest X-ray, and 41 patients with chronic obstructive pulmonary disease (COPD) or asthma.
Significant differences were found in mean 8-isoprostane levels between the three groups (p = 0.027), and post-hoc tests found higher levels in the lung cancer patients than in patients with benign nodules (p = 0.032) and COPD/asthma (p = 0.014). The receiving operating characteristic area under the curve (AUC) was 0.69 for differentiating the lung cancer group from the benign nodule group, and 0.7 for differentiating from the COPD/asthma group.
The UPLC-MS/MS-based method is an efficient analytical tool for measuring 8-isoprostane plasma concentrations. The results suggest exploring its utility as a marker for early lung cancer screening.

In Italy, the production of manila clams (Ruditapes philippinarum, Adams and Reeve, 1850) is mainly localized in northern Adriatic lagoons in the Po River delta, where shellfish farming provides important socio-economic revenue. However, in our globalized world, the seafood market is threated by fraudulent activities, in which agri-food products whose provenance is not certified are sold, posing a risk to consumer health. Multi-isotope ratio analysis is commonly used to trace the provenance of goods produced in different countries with different climatic and environmental conditions. Here, we investigated the reliability of this approach in terms of tracing the exact provenance of manila clams harvested in three Adriatic northern lagoons that are close to each other. We also verified the origin of samples bought at a local supermarket with a certificate of provenance. We carried out elemental analyses of carbon (C), nitrogen (N), and sulfur (S) and the respective isotopic ratios (13C/12C; 15N/14N; 34S/32S) on manila clam tissues, plus isotopic analyses of carbon (13C/12C), oxygen (18O/16O), and strontium (87Sr/86Sr) on manila clam shells. Each isotopic parameter can be used to identify the marine and continental contributions of water and/or nutrient supplies occurring in the lagoons. Therefore, the combination of isotopic parameters in a linear discriminant analysis (LDA) allowed for the identification of the lagoons in which the manila clams were produced.