In this paper, a method of defining the even-even deformed nuclei inertial parameters is suggested. Calculations for isotopes 162-168Hf and 164-176Yb are listed. The parameters of inertia of rotational nuclei are also defined. Dependence of the parameters of inertia on the nucleons number is shown.
The dynamics of the coastal aquifers are well-expressed by geochemical and isotopic signatures. Coastal regions often exhibit complex groundwater recharge pattern due to the influence of depression in the Bay of Bengal, tidal variations on surface waters, saline water intrusion and agricultural return flows. In this research, groundwater recharge processes occurring in coastal Tamil Nadu, South India were evaluated using major ion chemistry and environmental isotopes. A total of 170 groundwater samples were collected from shallow and deep aquifers during both post-monsoon (POM) and pre-monsoon (PRM) seasons. The isotopic results showed a wide variation in the shallow groundwater, suggesting contribution from multiple recharge sources. But, the deeper groundwater recharge is mainly from precipitation. The northern part of the study area showed more depleted isotopic values, which rapidly changed towards south from -6.8 to -4.4‰. Alternatively, central and southern parts exhibited relatively enriched isotopic content with variation from -0.58 to -2.7‰. Groundwater was discerned to be brackish to saline with chloride content, 600-2060 mgL-1 and δ18O ranging from -5.8 to -4.5‰, suggesting influence of the saline water sources. A minor influence of anthropogenic activities was also observed in the deeper groundwater during PRM, which was confirmed by tritium and Cl- trends. The old groundwater with depleted isotopic content infer recharged by distant sources while modern groundwater with enriched isotopes points to the influence of evaporated recharge.
In this study, estuarine water samples were collected at diverse hot spots in Miri River Estuary, East Malaysia to appraise the geochemical processes, which controls the river water quality. The collected water samples were analysed for various physicochemical parameters (insitu parameters, nutrients, major ions and trace metals), including stable isotopes (oxygen and hydrogen). Suspended solids are also extracted from the water samples and analysed for trace metals. Standard graphs, Piper plot, Gibbs diagram, water quality indices, geochemical modelling and statistical analysis were used for the data analysis. The acquired water quality data was compared with national and international guidelines for the suitability of water for various purposes. Interpretation of data reveals that the estuarine water quality is deemed unsuitable to be used for both drinking and irrigation purposes. Overall, the elemental concentrations are increasing from downstream to river mouth. Based on pollution indices (HEI and Cd), downstream region shows high vulnerability to metal pollution due to anthropogenic disturbance. Isotope values of river water indicate direct atmospheric precipitation with minimal evaporation. Factor analysis reveals that seawater influx, urban pollution, domestic and agricultural discharges at the downstream region are the main controlling factors to the river water quality. It is also deduced that suspended solids play a vital role in the adsorption and desorption of trace metals in the estuarine water. The outcome of this study provides a comprehensive information on pollution status of Miri estuary, which helps the policy makers to practice sustainable management of this water resource for Miri community.
The potential for the isotopic ratio analysis of cattle tail hair in determining the geographical origin of raw cow milk in Peninsular Malaysia had been investigated in this research using exploratory visualization. A significant positive correlation (p<0.0001) (n=54) was noticed between δ(13)C and δ(15)N in milk with that of hair which indicated that these matrices could be used in tracing the geographical origin of animal produce and tissues, and there is a possibility that hair could be used as a substitute in building the database for the geographical traceability of milk. It was also observed that both hair and milk isotopic ratio correlations exhibited separation between the northern and southern regions. The accuracy of using isotopic ratio in determining geographical discrimination had been clearly demonstrated when several commercial milk samples from the same regions under the study were correctly assigned to the appropriate geographical clusters.
Multivariate stable isotope analysis combined with chemometrics was used to investigate and discriminate rice samples from six rice producing provinces in China (Heilongjiang, Jilin, Jiangsu, Zhejiang, Hunan and Guizhou) and four other Asian rice producing countries (Thailand, Malaysia, Philippines, and Pakistan). The stable isotope characteristics were analyzed for rice of different species cultivated with varied farming methods at different altitudes and latitudes/longitudes. The index groups of δ13C, δ15N, δ18O, 207/206Pb and 208/207Pb were screened and established for the selected samples with different geographical features by means of principal component analysis (PCA) and discriminant analysis (DA), which would provide a sound technical solution for rice traceability and serve as a template for further research on the traceability of other agricultural products, especially plant-derived products.
The identification of nitrogen sources and cycling processes is critical to the management of nitrogen pollution. Here, we used both stable (δ15N-NO3-, δ18O-NO3-, δ15N-NH4+) and radiogenic (222Rn) isotopes together with nitrogen concentrations to evaluate the relative importance of point (i.e. sewage) and diffuse sources (i.e. agricultural-derived NO3- from groundwater, drains and creeks) in driving nitrogen dynamic in a shallow coastal embayment, Port Phillip Bay (PPB) in Victoria, Australia. This study is an exemplar of nitrogen-limited coastal systems around the world where nitrogen contamination is prevalent and where constraining it may be challenging. In addition to surrounding land use, we found that the distributions of NO3- and NH4+ in the bay were closely linked to the presence of drift algae. Highest NO3- and NH4+ concentrations were 315 μmol L-1 and 2140 μmol L-1, respectively. Based on the isotopic signatures of NO3- (δ15N: 0.17 to 21‰; δ18O: 3 to 26‰) and NH4+ (δ15N: 30 to 39‰) in PPB, the high nitrogen concentrations were attributed to three major sources which varied between winter and summer; (1) nitrified sewage effluent and drift algae derived NH4+ mainly during winter, (2) NO3- mixture from atmospheric deposition, drains and creeks predominantly observed during summer and (3) groundwater and sewage derived NO3- during both surveys. The isotopic composition of NO3- also suggested the removal of agriculture-derived NO3- through denitrification was prevalent during transport. This study highlights the role of terrestrial-coastal interactions on nitrogen dynamics and illustrates the importance of submarine groundwater discharge as a prominent pathway of diffuse NO3- inputs. Quantifying the relative contributions of multiple NO3- input pathways, however, require more extensive efforts and is an important avenue for future research.
One of the most common types of adulteration of honey involves the addition of invert sugar syrups. A new method was developed to measure the stable isotope ratios of carbon and carbon-bound non-exchangeable (CBNE) hydrogen from specific molecular positions in fructose and glucose in honey. This was achieved through periodate oxidation of the sugars to produce formaldehyde, followed by reaction with ammonia to form hexamethylenetetramine (HMT). The preparation was simplified, optimized, and validated by isotopic analysis of replicate syntheses of HMT from fructose, glucose, sugar syrup and a representative authentic honey sample. The optimized method had a repeatability standard deviation from 1.5‰ to 3.0‰ and from 0.1‰ to 0.4‰ for δ2H and δ13C, respectively. This methodology has advantages over alternative isotopic methods, for measuring CBNE hydrogen isotope ratios in sugars, in terms of time, sensitivity and operability and offers a complementary method to differentiate authentic honey from invert sugar syrups.
We present precipitation isotope data (δ2H and δ18O values) from 19 stations across the tropics collected from 2012 to 2017 under the Coordinated Research Project F31004 sponsored by the International Atomic Energy Agency. Rainfall samples were collected daily and analysed for stable isotopic ratios of oxygen and hydrogen by participating laboratories following a common analytical framework. We also calculated daily mean stratiform rainfall area fractions around each station over an area of 5° x 5° longitude/latitude based on TRMM/GPM satellite data. Isotope time series, along with information on rainfall amount and stratiform/convective proportions provide a valuable tool for rainfall characterisation and to improve the ability of isotope-enabled Global Circulation Models to predict variability and availability of inputs to fresh water resources across the tropics.
Pulau Redang and Pulau Tioman have experienced huge tourism growth over the last two decades, but minimal sewage treatment may threaten the resilience of their coral reefs. This study uses stable isotope techniques to identify suitable bioindicators of sewage nutrients (δ15N) at these islands by measuring macroalgae (Lobophora spp.), gastropods (Drupella spp.), scleractinian coral (Acropora spp.), and leather coral (Sinularia spp.). At tourist hubs using seepage septic tank systems, enrichment of Acropora δ15N (Redang, +0.7‰) and Sinularia δ15N (Tioman, +0.4‰) compared to pristine background levels indicate enhanced sewage nutrient discharge. Carbon isotopes and survey data suggest that sedimentation did not confound these δ15N trends. Potential damaging effects of sewage discharge on the coral reef communities at both islands are highlighted by strong correlations between Acropora δ15N and regional variation in coral reef community structure, and exclusive occurrence of degraded reefs at regions of high sewage influence.
Plant functional traits regulate ecosystem functions but little is known about how co-occurring gradients of land use and edaphic conditions influence their expression. We test how gradients of logging disturbance and soil properties relate to community-weighted mean traits in logged and old-growth tropical forests in Borneo. We studied 32 physical, chemical and physiological traits from 284 tree species in eight 1 ha plots and measured long-term soil nutrient supplies and plant-available nutrients. Logged plots had greater values for traits that drive carbon capture and growth, whilst old-growth forests had greater values for structural and persistence traits. Although disturbance was the primary driver of trait expression, soil nutrients explained a statistically independent axis of variation linked to leaf size and nutrient concentration. Soil characteristics influenced trait expression via nutrient availability, nutrient pools, and pH. Our finding, that traits have dissimilar responses to land use and soil resource availability, provides robust evidence for the need to consider the abiotic context of logging when predicting plant functional diversity across human-modified tropical forests. The detection of two independent axes was facilitated by the measurement of many more functional traits than have been examined in previous studies.
Analyses activities of 226 Ra and 228 Ra were conducted at ten stations of Pulau Redang, Malaysia. Dissolved radium isotopes such as 226 Ra and 228 Ra had shown enrichment at coastal area stations. Meanwhile, activities of both nuclides in the suspended particle matters were slightly in equilibrium with the activity ratio ranging from 0.88 – 1.86. The calculated distribution coefficient values (Kd) of 226 Ra and 228 Ra were in the range of 0.78 x 10 5 L g -1 to 5.56 x 10 5 L g -1 and 0.21 x 10 5 L g -1 to 1.86 x 10 5 L g -1 , respectively, indicate that most of the radium nuclides in the study area are strongly absorbed into the particulate phases. Therefore, low concentrations of suspended particles matter in the water column (< 10 mg L -1 ) have insignificant effects on the Kd values.
This paper presents data on nitrogen characteristics in a tropical seagrass meadow located in Sungai Pulai estuary (Johor, Malaysia) and is related to the article "Nitrogen dynamics in tropical seagrass meadows under heavy anthropogenic influence" [1]. Field sampling conducted from August 2015 to May 2016 aimed to collect sediments and seagrass tissues for analysis of nitrogen elemental content and stable isotope values. Sediment samples and seagrass tissue (above-ground and below-ground parts) were collected by using PVC cores. The information is presented as unprocessed and partially data, which incorporates nitrogen content (in %) and δ15N values (‰) of sediment and seagrass tissue samples. Nitrogen loadings in the seagrass sediments, as based on down-core data of sediment samples up to 30 cm depths, should be read with [1] to comprehend the baseline nitrogen dynamics of the study area.
Trophic variation in food web structure occurs among and within ecosystems. The magnitude of variation, however, differs from system to system. In ephemeral pond ecosystems, temporal dynamics are relatively more important than in many systems given that hydroperiod is the ultimate factor determining the presence of an aquatic state. Here, using stable isotopes we tested for changes in trophic chain length and shape over time in these dynamic aquatic ecosystems. We found that lower and intermediate trophic level structure increased over time. We discuss these findings within the context of temporal environmental stability. The dynamic nature of these ephemeral systems seems to be conducive to greater levels of intermediate and lower trophic level diversity, with omnivorous traits likely being advantageous.
Aerosol black carbon (BC) is a short-lived climate pollutant. The poorly constrained provenance of tropical marine aerosol BC hinders the mechanistic understanding of extreme climate events and oceanic carbon cycling. Here, we collected PM2.5 samples during research cruise NORC2016-10 through South China Sea (SCS) and Northeast Indian Ocean (NEIO) and measured the dual-carbon isotope compositions (δ13C-Δ14C) of BC using hydrogen pyrolysis technique. Aerosol BC exhibits six different δ13C-Δ14C isotopic spaces (i.e., isotope provinces). Liquid fossil fuel combustion, from shipping emissions and adjacent land, is the predominant source of BC over isotope provinces "SCS close to Chinese Mainland" (53.5%), "Malacca Strait" (53.4%), and "Open NEIO" (40.7%). C3 biomass burning is the major contributor to BC over isotope provinces "NEIO close to Southeast Asia" (55.8%), "Open NEIO" (41.3%), and "Open SCS" (40.0%). Coal combustion and C4 biomass burning show higher contributions to BC over "Sunda Strait" and "Open SCS" than the others. Overall, NEIO near the Bay of Bengal, Malacca Strait, and north SCS are three hot spots of fossil fuel-derived BC; the first two areas are also hot spots of biomass-derived BC. The comparable δ13C-Δ14C between BC in aerosol and dissolved BC in surface seawater may suggest atmospheric BC deposition as a potential source of oceanic dissolved BC.
Stable carbon isotope ratio measurements are used to investigate the provenance of vanillin. In this study, a variety of commercial vanillin samples and vanilla products were analyzed to provide a frame of reference for the variability of carbon isotope delta values in various vanillin samples, with the results ranging from -20.6 to -36.7‰ relative to the Vienna Peedee Belemnite (VPDB). We present information on the development of two synthetic vanillin reference materials, VANA-1 and VANB-1, prepared in 0.75 g units in glass vials, to be used for the calibration of carbon isotope delta measurements of vanillin and other easily combustible organic materials. Characterization of 40 vials each of VANA-1 and VANB-1 was performed by three laboratories over several measurement sequences. The certified carbon isotope delta values are -31.30 ± 0.06‰ (VANA-1) and -25.85 ± 0.05‰ (VANB-1). These uncertainties, for the 95% confidence level, include considerations for measurement uncertainty, coherence of the reference materials used for calibration, batch homogeneity, and stability during storage and transportation. The results are traceable to the VPDB through a set of nine reference materials (IAEA-CH-6, USGS65, IAEA-600, NBS22, USGS61, IAEA-603, IAEA-610, IAEA-611, and IAEA-612). For up to date certified values, users should refer to doi.org/10.4224/crm.2022.vana-1 and doi.org/10.4224/crm.2022.vanb-1.
Lead contamination in topsoil of the mining and smelting area of Mitrovica, Kosovo, was investigated for total concentrations and chemical fractions by sequential extraction analysis, mineralogical fractions by X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectrometer (SEM-EDX). The study revealed that all samples contained Pb exceeding USEPA standard of 400 mg kg-1. The highest total concentration of Pb (125,000 mg kg-1) was the soil from the former smelter. Sequential extraction results showed that the predominant form of Pb was associated with Fe-Mn oxide-bound fraction which ranged from 45.37 to 71.61% of total concentrations, while carbonate and silicate Pb-binding fractions were dominant when physical measurements (XRD and SEM-EDX) were applied. Application of Pb isotope ratios (206Pb/207Pb and 208Pb/206Pb), measured by inductively coupled plasma mass spectrometry, identified that Pb contamination is originated from similar anthropogenic source. The results reflected that the Pb contamination in the soil of this area is serious. In order to provide proper approaches on remediation and prevention of health impacts to the people in this area, a continuous monitoring and health risk assessment are recommended.
A total of 33 crude palm oil samples were randomly collected from different regions in Malaysia. Stable carbon isotopic composition (δ13C) was determined using Flash 2000 elemental analyzer while hydrogen and oxygen isotopic compositions (δ2H and δ18O) were analyzed by Thermo Finnigan TC/EA, wherein both instruments were coupled to an isotope ratio mass spectrometer. The bulk δ2H, δ18O and δ13C of the samples were analyzed by Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA) and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). Unsupervised HCA and PCA methods have demonstrated that crude palm oil samples were grouped into clusters according to respective state. A predictive model was constructed by supervised OPLS-DA with good predictive power of 52.60%. Robustness of the predictive model was validated with overall accuracy of 71.43%. Blind test samples were correctly assigned to their respective cluster except for samples from southern region. δ18O was proposed as the promising discriminatory marker for discerning crude palm oil samples obtained from different regions. Stable isotopes profile was proven to be useful for origin traceability of crude palm oil samples at a narrower geographical area, i.e. based on regions in Malaysia. Predictive power and accuracy of the predictive model was expected to improve with the increase in sample size. Conclusively, the results in this study has fulfilled the main objective of this work where the simple approach of combining stable isotope analysis with chemometrics can be used to discriminate crude palm oil samples obtained from different regions in Malaysia. Overall, this study shows the feasibility of this approach to be used as a traceability assessment of crude palm oils.
This study considered the temporal variations in rainfall and water level patterns as governing factors, which influence the geochemical process of coastal aquifer around Pondicherry, South India. Rainfall and water level data were collected from 2006 to 2016, which showed that the amount of rainfall from 2006 to 2011 was higher than that of 2011 to 2016. To understand the geochemical process governing groundwater, samples were collected during 2006 (n = 54), followed by 2011 (n = 93), and during 2016 (n = 63) as part of continuous observation. The major ions and stable isotopes (δ18O and δD) were analyzed in the samples to determine the geochemical variations. The predominant types were noted as Na-HCO3 and Na-Cl; Ca-HCO3 and Ca-Mg-Cl; and Na-Cl and Ca-Mg-Cl in 2006, 2011, and 2016, respectively. Saturation states of sulfate and carbonate minerals were compared for the study periods and it indicates that the saturation index (SI) values were increased from 2006 to 2011, but decreased from 2011 to 2016. PHREEQC inverse modeling revealed the predominance for the dissolution and leaching of carbonate minerals during increased rainy periods, and the increase of halite saturation during lesser rainfall period. AQUACHEM mixing studies suggested that geochemical signatures of 2006 and 2011 were preserved in samples of 2016 in different proportions. Considering the major factors, the main processes prevailing in the study area were inferred to be dissolution and leaching during 2006~2011 years and seawater intrusion along with ion exchange during 2011~2016 years. In all these periods of study, anthropogenic impact was also identified in the groundwater samples. Hence, this study revealed that the rainfall and water level gave a significant variation in the geochemical process of groundwater in the coastal aquifer system.
NMR measurements ((119)Sn chemical shift, line width and (13)C relaxation) were made on triphenyltin chloride in two solutions, 2.5 and 0.75 mol% in CDCl(3), at several temperatures. The (13)C spin-lattice relaxation time and NOE data for the phenyl carbons provide the corresponding correlation times for the overall molecular reorientational motion and the internal rotation of the phenyl groups. The results are indicative of a weak intermolecular association of the triphenyltin chloride molecules in solution and are discussed with reference to a model for intermolecular phenyl ring π-π stacking interactions.
Studies have shown that food chain length is governed by interactions between species richness, ecosystem size and resource availability. While redundant trophic links may buffer impacts of species loss on food chain length, higher extinction risks associated with predators may result in bottom-heavy food webs with shorter food chains. The lack of consensus in earlier empirical studies relating species richness and food chain length reflects the need to account robustly for the factors described above. In response to this, we conducted an empirical study to elucidate impacts of land-use change on food chain length in tropical forest streams of Southeast Asia. Despite species losses associated with forest loss at our study areas, results from amino acid isotope analyses showed that food chain length was not linked to land use, ecosystem size or resource availability. Correspondingly, species losses did not have a significant effect on occurrence likelihoods of all trophic guilds except herbivores. Impacts of species losses were likely buffered by initial high levels of trophic redundancy, which declined with canopy cover. Declines in trophic redundancy were most drastic amongst invertivorous fishes. Declines in redundancy across trophic guilds were also more pronounced in wider and more resource-rich streams. While our study found limited evidence for immediate land-use impacts on stream food chains, the potential loss of trophic redundancy in the longer term implies increasing vulnerability of streams to future perturbations, as long as land conversion continues unabated.