Reconstructing Middle and Upper Paleolithic human mobility in Portuguese Estremadura through laser ablation strontium isotope analysis.

Understanding mobility and landscape use is important in reconstructing subsistence behavior, range, and group size, and it may contribute to our understanding of phenomena such as the dynamics of biological and cultural interactions between distinct populations of Upper Pleistocene humans. However, studies using traditional strontium isotope analysis are generally limited to identifying locations of childhood residence or nonlocal individuals and lack the sampling resolution to detect movement over short timescales. Here, using an optimized methodology, we present highly spatially resolved 87Sr/86Sr measurements made by laser ablation multicollector inductively coupled plasma mass spectrometry along the growth axis of the enamel of two marine isotope stage 5b, Middle Paleolithic Neanderthal teeth (Gruta da Oliveira), a Tardiglacial, Late Magdalenian human tooth (Galeria da Cisterna), and associated contemporaneous fauna from the Almonda karst system, Torres Novas, Portugal. Strontium isotope mapping of the region shows extreme variation in 87Sr/86Sr, with values ranging from 0.7080 to 0.7160 over a distance of c. 50 km, allowing short-distance (and arguably short-duration) movement to be detected. We find that the early Middle Paleolithic individuals roamed across a subsistence territory of approximately 600 km2, while the Late Magdalenian individual parsimoniously fits a pattern of limited, probably seasonal movement along the right bank of the 20-km-long Almonda River valley, between mouth and spring, exploiting a smaller territory of approximately 300 km2. We argue that the differences in territory size are due to an increase in population density during the Late Upper Paleolithic.

A Neandertal dietary conundrum: Insights provided by tooth enamel Zn isotopes from Gabasa, Spain.

The characterization of Neandertals' diets has mostly relied on nitrogen isotope analyses of bone and tooth collagen. However, few nitrogen isotope data have been recovered from bones or teeth from Iberia due to poor collagen preservation at Paleolithic sites in the region. Zinc isotopes have been shown to be a reliable method for reconstructing trophic levels in the absence of organic matter preservation. Here, we present the results of zinc (Zn), strontium (Sr), carbon (C), and oxygen (O) isotope and trace element ratio analysis measured in dental enamel on a Pleistocene food web in Gabasa, Spain, to characterize the diet and ecology of a Middle Paleolithic Neandertal individual. Based on the extremely low δ66Zn value observed in the Neandertal's tooth enamel, our results support the interpretation of Neandertals as carnivores as already suggested by δ15N isotope values of specimens from other regions. Further work could help identify if such isotopic peculiarities (lowest δ66Zn and highest δ15N of the food web) are due to a metabolic and/or dietary specificity of the Neandertals.

Sr/Ca ratios indicate frugivory versus folivory in primates: a case study using handheld XRF in Kibale National Park, Uganda.

Researchers often use trace element concentrations, including strontium-calcium ratios (Sr/Ca), to reconstruct paleodiets. While most commonly used as a proxy for meat consumption, a more appropriate application may be to differentiate frugivory from folivory. Sr/Ca ratios in animal tissue reflect the Sr/Ca ratios of the highest calcium components of that animal's diet. Because plants have much higher concentrations of calcium than meat, meat consumption signals are often overwhelmed by the variation in Sr/Ca ratios coming from different plant parts. This study uses faunal and plant data from Kibale National Park, a protected forest in southwestern Uganda home to numerous primate species (for example, common chimpanzees and baboons), to assess the reliability of Sr/Ca ratios to differentiate between primate dietary groups. We find that leaves consistently have higher strontium and calcium concentrations than fruits and that this is mirrored in higher Sr/Ca ratios in folivorous primates compared to frugivorous primates. Plant species differ widely in both their overall Sr/Ca ratios and the differences between their fruit and leaf Sr/Ca ratios, but this variation does not overwhelm the dietary signal separating frugivores and folivores. Furthermore, this research demonstrates that non-destructive and portable X-ray florescence (XRF) methods are an effective means of gathering Sr/Ca data from plant and faunal material, increasing the opportunities to apply such methods to fossil material in the future.

Unravelling the life-history patterns and habitat preferences of the Japanese eel (Anguilla japonica) in the Pearl River, China.

Eels have fascinated biologists for centuries due to their amazing long-distance migrations between freshwater habitats and very distant ocean spawning areas. The migratory life histories of the Japanese eel, Anguilla japonica, in the waters of south China are not very clear despite its ecological importance, and the need for fishery regulation and management. In this study, strontium (Sr) and calcium (Ca) microchemical profiles of the otoliths of silver eels were measured by X-ray electron probe microanalysis based on data collected from different habitats (including freshwater and brackish habitats), in the large subtropical Pearl River. The corresponding habitat preference characteristics were further analysed using redundancy analysis (RDA). A total of 195 Japanese eels were collected over 6 years. The collected individuals ranged from 180 to 771 mm in total length and from 8 to 612 g in body weight. Two-dimensional pictures of the Sr:Ca concentrations in otoliths revealed that the A. japonica in the Pearl River are almost entirely river eels, spending the majority of their lives in fresh water without exposure to salt water, while the catadromous migration time has delayed about 1 month in the Pearl River estuary in the past 20 years. RDA analysis further indicated that juveniles and adults preferred water with high salinity and high tide levels. Youth preferred habitats with high river fractals. Our findings contribute to a growing body of evidence showing that the eels are extremely scarce currently and conservation measures against them are imminent, including the protection of brackish and freshwater areas where they live in south China.

The incorporation of strontium and barium into the otoliths of the flounder Paralichthys olivaceus at early life stages demonstrates resilience to ocean acidification.

Ocean acidification could modify the bioavailability and chemical properties of trace elements in seawater, which could affect their incorporation into the calcareous structures of marine organisms. Fish otoliths, biomineralized ear stones made by aragonite, are suspended within the endolymph fluid of teleosts, indicating that the elemental incorporation of otoliths might also be susceptible to ocean acidification. In this study, we evaluated the combined effects of CO2-induced ocean acidification (pH 8.10, 7.70, and 7.30, corresponding to ocean acidification scenarios under the representative concentration pathway 8.5 model as projected by the Intergovernmental Panel on Climate Change) and water elemental concentrations of strontium (Sr) and barium (Ba; low, medium, and high) on elemental incorporation into otoliths of the flounder Paralichthys olivaceus at early life stages. Our results revealed that the elemental incorporation of Sr and Ba into otoliths was principally dependent on the corresponding water elemental concentrations rather than on ocean acidification. Moreover, the partition coefficients (DMe) of Sr and Ba may stabilize after dynamic equilibrium is reached as the water elemental concentration increases, but are not affected by ocean acidification. Therefore, the incorporation of Sr and Ba into otoliths of the flounder at early life stages may not serve as an effective indicator of ocean acidification. In other words, the findings suggest that ocean acidification does not impact the incorporation of Sr and Ba incorporation into otoliths when tracing the temperature or salinity experiences of the flounder. Our findings will provide new knowledge for understanding the potential ecological effects of ocean acidification on the recruitment dynamics of fish species.

Strontium leaching from municipal waste subjected to incineration.

The aim of the study was to determine the content and leachability of Sr in ashes obtained through combusting municipal waste in household furnaces. The waste had been collected as a mixed stream and as separate fractions (i.e. furniture, sponges, waste paper, PCV packaging, plastic-coated paper cartons, imitation leather, rubber, textiles and polystyrene). Using single-step chemical extractions, (HCl + HNO3, H2O, 0.01 M CaCl2, 0.1 M CH3COOH), we determined the total content of Sr (TC) and proportions of the following fractions: water-leachable, phytoavailable and easily soluble and bound to carbonates. We also analyzed the effect of reducing pH in the extraction solutions on St leachability from the study material. The study showed that Sr concentration in ash generated from the combustion of conventional fuels, alternative fuels and municipal waste ranged from 114 to 1006 mg/kg. The largest amounts of Sr were found in ash generated from the combustion of alternative fuels (coal pellets 488-1006 mg/kg), conventional fuels (hard coal 430-670 mg/kg) and mixed waste (237-825 mg/kg). The most mobile fraction of Sr (water-leachable) comprised from 1.3% to nearly 91% TC; the phytoavailable fraction and the ion-exchange and carbonate-bound fraction comprised 3-92% TC and 9-72% TC, respectively. We also found that the greatest pH reductions do not always entail the greatest amounts of extracted Sr. A much more significant factor in this respect is the mineral and chemical composition of primary materials, which can buffer changes in pH. The Risk Assessment Code (RAC) values pointed to a varied environmental risk and the highest RAC values (> 70) were found for coal pellets, wood pellets, straw, rubber and plastic containers for mixed oils.

Exposure to metal mixtures and young children's growth and development: A biomonitoring-based study in Eastern China.

Exposure to metal mixtures may affect children's health but the conclusions are controversial. We aimed to investigate the associations of metal mixture exposure with children's physical and behavioral development. 15 metals were detected in the urine samples of 278 preschoolers aged 3-6 years from eastern China. Multiple linear models and restricted cubic splines were used to evaluate dose-response relationships between single metal and children's physical and behavioral development. The Bayesian Kernel Machine Regression (BKMR) models, the weighted quantile sum (WQS) models and Quantile G-Computation were applied to evaluate the joint effects of metal mixtures. The results showed that arsenic (As) was negatively associated with z score of height for age (HAZ) in individual-metal models [ß (95%CI): - 0.22 (-0.38, -0.06), P = 0.006]. Concerning children's behavioral development, multiple-metal models demonstrated a negative association with strontium (Sr) [ß (95%CI): - 0.82 (-1.38, -0.26), P = 0.004], and a positive association with tin (Sn) [ß (95%CI): 0.69 (0.16, 1.21), P = 0.010]. Notably, these associations remained significant or suggestive even after adjustments for multiple tests, sensitivity analyses, and application of different statistical models, including BKMR, WQS, and Quantile G-Computation. Furthermore, the study identified a negative joint effect of the metal mixture on HAZ, as demonstrated by BKMR and Quantile G-Computation models, with As playing an irreplaceable role in this observed impact. In summary, exposure to As appears to have adverse effects on HAZ, while exposure to Sn may hinder children's behavioral development. Conversely, exposure to Sr may have a protective effect on children's behavioral development. Additionally, the combined impact of metal mixtures is implicated in potentially impairing children's physical development, particularly in terms of HAZ.

Elemental analysis of vertebrae discerns diadromous movements of threatened non-marine elasmobranchs.

River sharks (Glyphis spp.) and some sawfishes (Pristidae) inhabit riverine environments, although their long-term habitat use patterns are poorly known. We investigated the diadromous movements of the northern river shark (Glyphis garricki), speartooth shark (Glyphis glyphis), narrow sawfish (Anoxypristis cuspidata), and largetooth sawfish (Pristis pristis) using in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on vertebrae to recover elemental ratios over each individual's lifetime. We also measured elemental ratios for the bull shark (Carcharhinus leucas) and a range of inshore and offshore stenohaline marine species to assist in interpretation of results. Barium (Ba) was found to be an effective indicator of freshwater use, whereas lithium (Li) and strontium (Sr) were effective indicators of marine water use. The relationships between Ba and Li and Ba and Sr were negatively correlated, whereas the relationship between Li and Sr was positively correlated. Both river shark species had elemental signatures indicative of prolonged use of upper-estuarine environments, whereas adults appear to mainly use lower-estuarine environments rather than marine environments. Decreases in Li:Ba and Sr:Ba at the end of the prenatal growth zone of P. pristis samples indicated that parturition likely occurs in fresh water. There was limited evidence of prolonged riverine habitat use for A. cuspidata. The results of this study support elemental-environment relationships observed in teleost otoliths and indicate that in situ LA-ICP-MS elemental characterization is applicable to a wide range of elasmobranch species as a discriminator for use and movement across salinity gradients. A greater understanding of processes that lead to element incorporation in vertebrae, and relative concentrations in vertebrae with respect to the ambient environment, will improve the applicability of elemental analysis to understand movements across the life history of elasmobranchs into the future.

Three-dimension titanium phosphate aerogel for selective removal of radioactive strontium(II) from contaminated waters.

The effective removal of radioactive strontium (especially 90Sr) from nuclear wastewater is crucial to environmental safety. Nevertheless, materials with excellent selectivity in Sr removal remain a challenge since the similarity with alkaline earth metal ions in the liquid phase. In this work, a novel titanium phosphate (TiP) aerogel was investigated for Sr(II) removal from the radioactive wastewater based on the sol-gel method and supercritical drying technique. The TiP aerogel has amorphous, three-dimensional and mesoporous structures with abundant phosphate groups, which was confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), atomic force microscope (AFM) and Fourier transform infrared spectroscopy (FT-IR). The adsorbent exhibited high efficiency and selectivity for the removal of Sr(II) with an extensive distribution coefficient up to 4740.03 mL/g. The adsorption equilibrium reached within 10 min and the maximum adsorption capacity was 373.6 mg/g at pH 5. And the kinetics and thermodynamics data fitted well with the pseudo-second-order model and Langmuir model respectively. It can be attributed to the rapid trapping and slow intraparticle diffusion of Sr(II) inside the mesoporous channels of the TiP aerogel. Furthermore, TiP aerogel exhibited over 80% removal for 50 mg/L Sr2+ in real water systems (seawater, lake water and tap water). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy revealed that strong ionic bonding formed during Sr(II) adsorption with the phosphate group on TiP aerogel. These results indicated that TiP aerogel is a promising high-capacity adsorbent for the effective and selective capture of Sr(II) from radioactive wastewater.

Strontium isotope ratios in kidney stones reveal the environmental implications for humans in Beijing, China.

Kidney stones are a common disease that threatens human health on a global scale and are closely related to the contemporary environment. The strontium isotope ratio (87Sr/86Sr) has been widely used to trace the migration of ancient humans through bones and teeth, which recorded their bioavailable Sr from the environment. However, no 87Sr/86Sr data for kidney stones have been reported. Therefore, this study explored the Sr content of kidney stones and reported their 87Sr/86Sr data for the first time to reflect the environmental implications for humans; 66 calcium oxalate kidney stones collected in Beijing were measured for calcium (Ca), magnesium (Mg) and strontium (Sr) content to explore Sr distribution behavior in kidney stones, and 17 samples were tested for strontium isotopes. Ca and Mg had a joint effect on the Sr content of kidney stones, with magnesium having a stronger effect, whereas 87Sr/86Sr values were unaffected by these elements. The 87Sr/86Sr values of kidney stones ranged from 0.709662 to 0.710990, within the range of environmental soil and water in Beijing. Drinking water and surface soils (representing food sources) mainly contributed to the bioavailable Sr of kidney stones, while sea spray and dust storm did not. This study is the first to report 87Sr/86Sr values for kidney stones. Evidence of Sr isotope ratios in kidney stones reveals environmental implications for humans and bioavailable Sr sources, demonstrating a great potential of Sr isotope ratios at the intersection of life and environmental sciences.

Source tracing and chemical weathering implications of strontium in agricultural basin in Thailand during flood season: A combined hydrochemical approach and strontium isotope.

87Sr/86Sr of river water are of great significance in constraining oceanic strontium (Sr) record and terrestrial climate change due to the connection of continental weathering and the adjacent ocean. This work presents the geochemical characteristics of dissolved Sr and hydrochemistry, and estimates chemical weathering rate together with elemental Sr flux during the flood season of the Mun River, the largest tributary of Mekong River. Hydrochemistry analysis indicates the dominance of Cl- and HCO3- for major anions with the average of 34.6 and 43.0 mg/L, respectively, and Na+ and Ca2+ together dominated the cationic composition with the average of 22.9 and 10.5 mg/L, respectively. The ion concentrations during flood season were lower than that in dry season, implying tremendous river runoff due to extreme rainfall. The dissolved Sr ranges 6.1-237.5 µg/L with higher contents in the upper Mun. Sr contents in flood season are lower and less fluctuated than that in dry season, whereas the divergence between up and downstream becomes larger. 87Sr/86Sr ranges 0.7100-0.7597, slightly higher than global average. Elemental molar ratio analysis partly corroborates the inference from correlation analysis, but 87Sr/86Sr does not correlate with Na/Ca, indicating additional influence except for the weathering of evaporites and silicates. Comparing to regional wastewater and rainwater, the lower reaches exhibits superimposed impact of agricultural inputs on weathering to dissolved loads, especially in downstream with more tributary convergence. Extreme rainfall during flood season and extensive agricultural production activities may interfere in altering riverine solutes. Silicate weathering rate and CO2 consumption rate are calculated as well as the yearly 87Sr in excess to the Mekong River and finally to the Pacific Ocean with a Sr flux of 1.98 × 103 tons/year, indicating significant influence on seawater strontium isotope evolution in the long run. Together with tropical climate and high-intensity precipitation, the accelerated chemical weathering process seems inevitable. Therefore, the impact of agricultural interference in the pan-Mekong River basin needs more systematic and multi-angle research to provide a comprehensive insight on better watershed management under tropical climatic conditions.

Nitrogen-fixing red alder trees tap rock-derived nutrients.

Symbiotic nitrogen (N)-fixing trees supply significant N inputs to forest ecosystems, leading to increased soil fertility, forest growth, and carbon storage. Rapid growth and stoichiometric constraints of N fixers also create high demands for rock-derived nutrients such as phosphorus (P), while excess fixed N can generate acidity and accelerate leaching of rock-derived nutrients such as calcium (Ca). This ability of N-fixing trees to accelerate cycles of Ca, P, and other rock-derived nutrients has fostered speculation of a direct link between N fixation and mineral weathering in terrestrial ecosystems. However, field evidence that N-fixing trees have enhanced access to rock-derived nutrients is lacking. Here we use strontium (Sr) isotopes as a tracer of nutrient sources in a mixed-species temperate rainforest to show that N-fixing trees access more rock-derived nutrients than nonfixing trees. The N-fixing tree red alder (Alnus rubra), on average, took up 8 to 18% more rock-derived Sr than five co-occurring nonfixing tree species, including two with high requirements for rock-derived nutrients. The increased access to rock-derived nutrients occurred despite spatial variation in community-wide Sr sources across the forest, and only N fixers had foliar Sr isotopes that differed significantly from soil exchangeable pools. We calculate that increased uptake of rock-derived nutrients by N-fixing alder requires a 64% increase in weathering supply of nutrients over nonfixing trees. These findings provide direct evidence that an N-fixing tree species can also accelerate nutrient inputs from rock weathering, thus increasing supplies of multiple nutrients that limit carbon uptake and storage in forest ecosystems.

Occurrence and distribution of heavy metals in water and soil sediments of Vellore District, Tamil Nadu, India.

The occurrence of heavy metals (HMs) in water and soil sediments represents a serious environmental concern. This study revealed the presence and distribution of HMs in water and soil sediments of various places in Vellore District, Tamil Nadu, India. Twenty-one sites were selected along the study area, and inductively coupled plasma-optical emission spectrometry (ICP-OES) was used to analyze the concentration of the heavy metals. The dominance of various HMs in the soil sediment sample follows the order strontium (Sr) > Manganese (Mn) > Barium (Ba) > Zinc (Zn) > Nickel (Ni) and Sr > Mn > Zn > Boron (B) > , respectively. It was found that the concentration of HMs in water and soil sediments in Ambur market and Mottukollai area was significantly higher than the recommended limits. Thus, the results showed that the presence of HMs in water and soil sediments could be threatened pollution factors unsafe for irrigation, drinking, and other human activities.

Relationship of the mobile forms of calcium and strontium in soils with their accumulation in meadow plants in the area of Kashin-Beck endemia.

This study was aimed at assessment of strontium and calcium mobility in soils and their accumulation with plants in the areas endemic for Kashin-Beck disease in Eastern Transbaikalia. The strontium and calcium mobility levels were determined using the method of sequential chemical extraction for 7 samples of meadow soils collected from the endemic region and 7 soil samples taken from conditionally control sites. To measure the Ca and Sr levels in the soil and plant samples, XRF analysis and AAS were used. The increased strontium level in the meadow soils of the endemic areas is accompanied by the element's higher mobility. The highest strontium yield was observed in the course of soil extraction using 1 M ammonium acetate, while the soils taken from the control sites gave lower amounts of the trace element. Furthermore, there is a positive correlation between the amount of the strontium extracted and its content in plants (r = + 0.86 - 0.98). At the sequential chemical extraction of calcium from the soils using the above method, the calcium yield was maximal in the ammonium acetate fraction (background sites) and in ammonium acetate and 6 M HCl fractions (endemic areas). The correlation between the amount of the calcium extracted in 1 M ammonium acetate and the macroelement levels found in plants was + 0.968. In addition, a peculiarly high accumulation of strontium in various willow species as compared to other meadow plants was revealed for the first time ever. Thus, the work introduces new data into the trace element biogeochemistry and environmental monitoring.

Health risk assessment of heavy metals and strontium in groundwater used for drinking and cooking in 58 villages of Prakasam district, Andhra Pradesh, India.

Groundwater is one of the most important sources of water for drinking and cooking in rural India. A total of 382 groundwater samples were collected from 58 villages and analyzed for HMs and Sr by inductively coupled plasma mass spectrometer. The average concentrations of HMs and Sr in water was in the order of strontium (Sr) > arsenic (As) > chromium (Cr) > lead (Pb) > mercury (Hg) > cadmium (Cd). Out of 58 villages, 21, 37, 35, 35, 35 and 39 villages had Cr, As, Cd, Hg, Pb and Sr higher (WHO limit) than their respectively permissible levels. Health risk assessment of HMs and Sr for humans revealed that the non-carcinogenicity hazard quotients (HQi+d) for HMs and Sr were higher than unity for adult and children. The hazard index (HI) was 531.066 for adult and 902.926 for children. The HI > 1 was observed in 45 villages for adults and 56 villages for children. The lifetime cancer risk in adult for Asi, Asd, and Pbi in 36, 25 and 23 villages, whereas in children was 42, 20 and 22 villages, respectively. In conclusion, the health risks arising from consumption of groundwater containing HMs and Sr indicated that there is a significant carcinogenic risks for adult and children. This is the first attempt to provide information on the health risks of Sr in drinking water in India. The present findings can be useful for the development of potential strategies for risk control and management.

Molecular Tweezers-like Calix[4]arene Based Alkaline Earth Metal Cation (Ca2+, Sr2+, and Ba2+) Chemosensor and Its Imaging in Living Cells and Zebrafish.

Although alkaline earth metal cations play an important role in our daily life, little attention has been paid to the field of fast quantitative analysis of their content due to a lack of satisfactory precision and a fast and convenient means of detection. In this study, we have designed a set of molecular tweezers based on the calix[4]arene chemosensor L, which was found to exhibit high selectivity and sensitivity toward Ca2+, Sr2+, and Ba2+ (by UV-vis and fluorescence methods) with low detection limits of the order of 10-7 to 10-8 M and high association constants (of the order of 106). More significantly, sensor L not only can recognize Ca2+, Sr2+, and Ba2+ but also can further discriminate between these three cations via the differing red shifts in their UV-vis spectra (560 nm for L·Ca2+, 570 nm for L·Sr2+, and 580 nm for L·Ba2+ complex) which is attributed to their different atomic radii. A rare synergistic effect for the recognition mechanism has been demonstrated by 1H NMR spectroscopic titration. Sensor L constructed a high shielding field by the cooperation of Tris with alkaline earth metal ion after complex. Additionally, the presence of acetoxymethyl group in sensor L results in enhancement of cell permeability, and as a consequence, sensor L exhibited excellent sensing and imaging (in vivo) in living cells and in zebrafish.

A high sensitivity system for luminescence measurement of materials.

A unique combined and multi-disciplinary wavelength multiplexed spectrometer is described. It is furnished with high-sensitivity imaging plate detectors, the power to which can be gated to provide time-resolved data. The system is capable of collecting spectrally resolved luminescence data following X-ray excitation [radioluminescence (RL) or X-ray excited optical luminescence (XEOL)], electron irradiation [cathodoluminescence (CL)] and visible light from light emitting diodes (LEDs) [photoluminescence (PL)]. Time-resolved PL and CL data can be collected to provide lifetime estimates with half-lives from microsecond timeframes. There are temperature stages for the high and low temperature experiments providing temperature control from 20 to 673 K. Combining irradiation, time resolved (TR) and TR-PL allows spectrally-resolved thermoluminescence (TL) and optically stimulated luminescence (OSL). The design of two detectors with matched gratings gives optimum sensitivity for the system. Examples which show the advantages and multi-use of the spectrometer are listed. Potential future experiments involving lifetime analysis as a function of irradiation, dose and temperature plus pump-probe experiments are discussed.

Variations in the migratory history of the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica in south-east Asian waters.

Fish movements between aquatic habitats of different salinity ranges (fresh, estuarine, marine) by the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica were examined by analysing the otolith strontium and calcium concentrations of yellow (immature) and silver (mature) stage eels collected in south-east Asian (Indonesia, Malaysia and Vietnam) waters. The ratios suggest that all migratory-type eels, including freshwater, brackish water and marine residents, pass the river mouth. However, the habitat preference was different among the sites (countries). In Indonesia and Vietnam, most A. bicolor bicolor and A. bicolor pacifica were either marine or brackish water residents in this study. Alternatively, most A. bicolor bicolor were freshwater residents in Malaysia; such a typical catadromous migration pattern in these eels has not been found in previous studies. The wide range of otolith Sr:Ca in both subspecies indicates that the habitat use of these tropical eels was opportunistic among fresh, brackish and marine waters during their growth phases following recruitment to coastal areas. The geographical variability of migratory histories suggests that habitat use might be determined by the inter and intraspecific competition and environmental conditions at each site.

Zirconium as a suitable reference element for estimating potentially toxic element enrichment in treated wastewater discharge vicinity.

The suitability of a reference element or normalizer used in assessing soil contamination levels using enrichment factor (EF) is important for soil quality assessment and monitoring. This study evaluated the results of using three reference elements Ti, Fe, and Zr for EF determination of Rb and Sr in soils within treated wastewater discharge vicinity, Central Botswana. The upper continental crust (UCC), world average values (WAV), and the local background values (LBV) were used in EF assessment of eight pedons. The elemental concentrations of the soils were determined with portable X-ray fluorescence (pXRF) analyzer. Relationships between the elements were strongly significant between Rb and Ti (r = 0.600, p < 0.01), Rb and Fe (r = 0.735, p < 0.01), Sr and Ti (r = 0.545, p < 0.01), and Sr and Fe (r = 0.841, p < 0.01). Second-level correlation analysis between contamination factor (CF) and EF levels showed Zr as the best reference element for Rb and Sr in the soils. Results from this study provide baseline knowledge necessary for contamination assessment and monitoring of soils with similar environmental conditions.

Evidence for dietary change but not landscape use in South African early hominins.

The dichotomy between early Homo and Paranthropus is justified partly on morphology. In terms of diet, it has been suggested that early Homo was a generalist but that Paranthropus was a specialist. However, this model is challenged and the issue of the resources used by Australopithecus, the presumed common ancestor, is still unclear. Laser ablation profiles of strontium/calcium, barium/calcium and strontium isotope ratios in tooth enamel are a means to decipher intra-individual diet and habitat changes. Here we show that the home range area was of similar size for species of the three hominin genera but that the dietary breadth was much higher in Australopithecus africanus than in Paranthropus robustus and early Homo. We also confirm that P. robustus relied more on plant-based foodstuffs than early Homo. A South African scenario is emerging in which the broad ecological niche of Australopithecus became split, and was then occupied by Paranthropus and early Homo, both consuming a lower diversity of foods than Australopithecus.