Watanabeite from the Pefka epithermal deposit, northeastern Greece, was examined using single-crystal X-ray diffraction and electron microprobe analysis. The empirical formula of watanabeite is Cu3.93Fe0.10Ag0.01Pb0.23As1.55Sb0.19S4.99. This mineral is orthorhombic, space group Amm2, with unit-cell parameters a = 10.9601(5), b = 14.6498(8), c = 10.3001(5) Å, V = 1653.82(14) Å3 and Z = 8. The crystal structure was solved and refined to R1 = 0.0471 for 2108 unique reflections with Fo > 4σ(Fo) and 123 refined parameters. The crystal structure of watanabeite can be described as a three-dimensional framework of Cu-centred tetrahedra; cavities of the tetrahedral scaffolding host Cu6S and As2(Pb,Sb,As)2S7 clusters. On the basis of structural data, the formula of watanabeite could be written as [III]Cu3[IV]Cu5As3(Pb,Sb,As)S10 (Z = 4), considering the three independent three-fold Cu sites and the three independent tetrahedrally coordinated Cu sites as aggregated positions. The occurrence of Pb2+ in watanabeite is probably related to the substitution Cu+ + (As,Sb)3+ = 2Me2+, where Me = Pb, Fe, Zn and formally divalent Cu. The relationships with tetrahedrite-group minerals are discussed on the basis of the refined structural model, highlighting possible crystal chemical implications of such relationships.

Siderophores are low molecular weight organic ligands synthesized by aerobic microorganisms to acquire Fe. In addition to Fe(III), siderophores may complex other metals such as Pb and Cd. This study compared the effects of the trihydroxamate siderophores desferrioxamine-B (DFO-B), desferrioxamine-D1 (DFO-D1), desferrioxamine-E (DFO-E), and the monohydroxamate siderophore-like ligand acetohydroxamic acid (aHA) on Pb and Cd (except for DFO-E) adsorption to kaolinite (KGa-1b) at pH 4.5 to 9, in 0.1 M NaClO4, at 22°C, in the dark. At pH >6, all of the studied ligands decreased Pb adsorption to kaolinite: aHA by 5–40% and DFO-B, DFO-D1 and DFO-E by 30–75%; the greater effects were at higher pH. The studied ligands decreased Cd adsorption to kaolinite at pH >8: aHA by 5–20% and the trihydroxamates by as much as 80%. We also observed enhancement of Pb adsorption in the presence of DFO-B at pH ≈5–6.0, probably due to adsorption of the doubly positively charged H3Pb (DFO-B)2+ complex, although spectroscopic evidence is needed.

There is a clear gap in the understanding of the desorption patterns of metals sorbed on soils and clays, despite their importance in the mobility, transport and fate of metals in natural environments. In this study, we investigated the desorption behavior of Cd, Zn and Pb sorbed on montmorillonite (Mt) and on hydroxyaluminum (HyA)- and hydroxyaluminosilicate (HAS)-Mt complexes. At pH 6.5, 2.5 g L–1 of HyA-Mt and HAS-Mt sorbed almost all of the 10–6 M Cd, Zn or Pb, while Mt under the same condition sorbed ~48, 49 and 55% of the added Cd, Zn and Pb, respectively. Based on pH50 values, the selectivity of metal sorption on Mt was Pb > Zn > Cd, and on the complexes, it was Pb ≫ Zn = Cd. In general, larger fractions of sorbed metals were remobilized from Mt than from the complexes. Again, in comparison with Pb, larger fractions of sorbed Cd and Zn were remobilized from different clays. Reducing the pHs of the equilibrium sorption systems from a fixed point (6.5) to different points (6.0, 5.5, 5.0, 4.5, and 4.0) and from different points (6.5, 6.0, 5.5, 5.0, and 4.5) to a fixed point (4.0) both yielded hysteretic metal desorption patterns. The fractions of Cd and Zn desorbed through Na and Cu exchange from the clays, especially from the complexes, were very different, indicating the existence of cation exchangeable metal sorption sites of weak and strong affinities on the complexes. Based on the EDTA-extractable fractions of Cd and Zn from HAS–Mt and HyA-Mt, it appeared that HyA–metal bonds are stronger than the HAS–metal bonds. Compared with other agents, acetic acid remobilized the highest fractions of all metals irrespective of the type of clays, with a concomitant release of Al or Al + Si. The Pb-HyA/HAS-Mt bonds were, however, still much too strong to be broken substantially by this mechanism. The results accomplished in this study suggest further attention to the fundamental understanding of the mobility, fate, bioavailability and toxicity of the concerned metals in soils and related environments.

The adsorption properties of clay minerals (e.g. montmorillonite and palygorskite) have been improved through chemical treatment methods. However, the addition of extra chemicals is often not friendly to the environment and powdered clay-mineral adsorbents are inconvenient for some applications. To overcome these drawbacks in the present study, granular montmorillonite-palygorskite adsorbents (GMPA) were successfully prepared using Na-alginate and thermal treatments to improve heavy metal removal from water. The properties of GMPA samples under different calcination temperatures were examined using thermogravimetric (TG) analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area (BET). The results indicated that loss of mass by GMPA relative to the untreated montmorillonite-palygorskite was due to the loss of water, adsorbed Na-alginate, and mineral decomposition during thermal treatment. Changes in the morphology and crystallinity were significant at calcination temperatures from 500°C to 1000°C. The layered morphology totally disappeared after calcination at 1000°C, while transformation of the montmorillonite and palygorskite to a non-crystalline material was almost complete at 800°C and new crystalline phases appeared. Calcination temperature had a significant influence on the specific surface areas and pore volumes of GMPA. Both the changes in texture and chemical structure affected Pb2+ and Cu2+ removal. The GMPA sample produced at a 600°C calcination temperature was the most promising adsorbent for heavy metal removal from water.

Clay minerals are effective adsorbents used for the remediation of toxic heavy metals from wastewater due to their large surface areas and great cation-exchange capacities. In this study, the removal of lead ions from aqueous solutions via adsorption was investigated using raw and iron-modified Turkish sepiolite. The aim of this study was to examine the effects of modification and environmental conditions on the sorptive properties of sepiolite samples. Initially, the raw sepiolite (Sep) and magnetic sepiolite/Fe2O3 composite (MagSep) prepared using the co-precipitation method were characterized via mineralogical and petrographical means and the physicochemical properties were determined. Then, the batch adsorption of lead (Pb2+) ions on the sepiolite samples was examined under various conditions (solution pH, adsorbent dosage, contact time, initial Pb2+ ion concentration, temperature, shaking rate). The adsorption capacity of MagSep was found to be greater than that of Sep under all experimental conditions. The results showed that the adsorption process followed a pseudo-second-order kinetic model, and the Langmuir isotherm best correlated with the experimental data. The maximum adsorption capacities were found to be 60.6 and 90.1 mg g–1 for Sep and MagSep, respectively. The characterization of the Pb-adsorbed sepiolite samples showed that lead formed covalent bonds with the sepiolite samples and attached to the sepiolite surface mainly through ion exchange. MagSep can be used efficiently in the field of wastewater treatment for the removal of Pb2+ ions as it does not release any toxic pollutants and can be separated easily with the use of a magnetic field.

The small finds discovered during the 1948–1951 excavations by Katherine M. Kenyon and John B. Ward-Perkins at Sabratha were scattered after the 1950s and have taken some time to be re-assembled. The following report on the small objects includes material in silver, copper alloy, iron, lead, glass, semiprecious stones, clay and stone, with a separate report on the substantial bone artefact assemblage. As well as providing the basic data on the objects, some of which are unique to Roman Libya, efforts have been made to put them into their Empire-wide context.

The excavation of a palaeochannel at the Vistre de la Fontaine 2-2 archaeological site, 3 km downstream from the ancient city of Nîmes (southeastern France), provided an accumulation sequence covering the last 2,500 years. Trace metal analyses of these alluvial sediments disclosed lead (Pb) contamination during the Early Roman Empire, with concentrations close to 1,000 ppm, a factor of 100 above the local geochemical background. This excess of Pb shows a uniform isotopic signature that may reflect unchanged ore sources, perhaps from the Massif Central or from Great Britain. The Pb peak accompanied visible waste that was transported in the sediments of the Vistre de la Fontaine at the time of the development of the Nîmes urban water supply and drainage network during the Early Roman Empire. This research shows the bimillennial persistence of palaeo-contamination in a peri-urban alluvial plain and the relevance of fluvial sedimentary archives in documenting ancient waste.

Immunological and oxidative alterations have been reported around calving in dairy cattle. In addition, the levels of heavy metals rise in the blood around parturition, which might affect body systems. Therefore, in this Research Communication we evaluate the changes in whole blood lead (Pb), arsenic (As), and cadmium (Cd) around calving, in comparison with the beginning of the dry period, and assess the correlations of these elements with immunological factors and oxidative markers. Samples were collected from 30 clinically healthy dairy cows in the early dry period (−6 w), one week before expected calving (−1 w), and one week postpartum (+1 w). The highest concentrations of Pb, As, and Cd were observed at −1 w and all the three elements decreased after parturition leading to significantly lower As and Cd, compared to −1 w (P < 0.05). The lowest levels of tumor necrosis factor-alpha, immunoglobulin G, interleukin 4, interleukin 10 and haptoglobin were found at −1 w simultaneous with the highest measures of the heavy metals, with tumor necrosis factor-alpha being significantly lower at this time (P < 0.05). At −6 w, As concentration was significantly (P < 0.05) correlated negatively (r = −0.366) and positively (r = 0.417) with total antioxidant capacity and malondialdehyde, respectively. Furthermore, at −1 w Pb and As had significant (P < 0.05) negative correlations with interferon gamma (r = −0.502) and interleukin 4 (r = −0.483), respectively. After parturition, Pb was observed to be negatively correlated with total antioxidant capacity (r = −0.538, P < 0.05). The observed results revealed that the alterations in immunological factors and antioxidant capacity around parturition were correlated with Pb and As levels.

Beneficial effects of human-animal contact on human health have contributed to the wide distribution of animal-assisted interventions (AAIs). While considerable effort has been devoted to the study of human welfare during AAIs, potential effects on therapy animals have been addressed less frequently. The aim of this study was to determine baseline and work-related levels of cortisol, a glucocor-ticoid hormone that mediates physiological responses to arousal, in certified therapy dogs and therapy dogs in training. All dogs (n = 21) participated in weekly group-AAIs in adult mental healthcare. Saliva samples were collected over the course of AAIs and on non-working days and analysed with a cortisol enzyme immunoassay. Analysis of the results revealed that according to their cortisol responses, both therapy dogs and therapy dogs in training were not stressed by AAIs. However, cortisol levels during work in certified therapy dogs performing AAIs on- and off-lead varied significantly, suggesting that further investigation into the use of a lead or other methods of giving therapy dogs opportunities to approach or avoid human contact is needed.

This work elucidated the performance and mechanisms of Pb2+ adsorption by kaolinite, montmorillonite, goethite and ferrihydrite using batch experiments. The contributions of various adsorption mechanisms were quantified using a stepwise extraction method. Several characterizations (scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, point of zero charge analysis and X-ray fluorescence) were utilized to analyse the physicochemical properties and the potential adsorption mechanisms. The results indicated that the adsorption processes of montmorillonite and goethite approached equilibrium within 20 min, while 60 min were required for the adsorption processes of kaolinite and ferrihydrite. The adsorption processes of Pb2+ by the four minerals best fit the pseudo-second order model. The adsorption capacities of the four minerals for Pb2+ followed the order: montmorillonite > goethite > ferrihydrite > kaolinite, and the maximum adsorption capacities were 69.20, 46.95, 34.32 and 18.62 mg g–1, respectively. The stepwise extraction test showed that the adsorption mechanism of Pb2+ was dominated by ion exchange for montmorillonite, precipitation and complexation for goethite and complexation for kaolinite and ferrihydrite.

As, Pb and Hg are common environmental contaminants in low- and middle-income countries. We investigated the association between child toxicant exposure and growth and development and determined if this association was mitigated by Se concentration. Toxicant concentrations in fingernail samples, anthropometry and Bayley’s Scales of Infant Development, 3rd edition domains were assessed in 36-month-old children whose mothers had been part of a randomised controlled trial in rural Vietnam. Multivariable regression analyses were performed to estimate the effect of toxicant exposure on clinical outcomes with adjustments for potential confounders and interaction with fingernail Se concentration. We analysed 658 children who had data for at least one physical or developmental outcome, and at least one toxicant measurement, and each of the covariates. Fingernail As concentration was negatively associated with language (estimate per 10 % increase in As: −0·19, 95 % CI: (–0·32, −0·05)). Pb was negatively associated with cognition (estimate per 10 % increase in Pb: −0·08 (–0·15, −0·02)), language (estimate per 10 % increase in Pb: −0·18 (–0·28, −0·10)) and motor skills (estimate per 10 % increase in Pb: −0·12 (–0·24, 0·00)). Hg was negatively associated with cognition (estimate per 10 % increase in Hg: −0·48, (–0·72, −0·23)) and language (estimate per 10 % increase in Hg −0·51, (–0·88, −0·13)) when Se concentration was set at zero in the model. As Se concentration increased, the negative associations between Hg and both cognition and language scores were attenuated. There was no association between toxicant concentration and growth. As, Pb and Hg concentrations in fingernails of 3-year-old children were associated with lower child development scores. The negative association between Hg and neurological development was reduced in magnitude with increasing Se concentration. Se status should be considered when assessing heavy metal toxicants in children and their impact on neurodevelopmental outcomes.

To determine the association between hearing loss and environmental Pb, Cd and Se exposure, a total of 1503 American adults from National Health and Nutrition Examination Survey (NHANES) (2011–2012) were assessed. The average of four audiometric frequencies (0·5, 1, 2 and 4 kHz) was used to identify speech-frequency hearing loss (SFHL), while the average of 3 audiometric frequencies (3, 4 and 6 kHz) was used to identify high-frequency hearing loss (HFHL). HFHL adjusted OR determined by comparing the highest and lowest blood Pb and Cd quartiles were 1·98 (95 % CI: 1·27, 3·10) and 1·81 (95 % CI: 1·13, 2·90), respectively. SFHL was significantly associated with blood Cd with the OR = 2·42 for the highest quartile. When further stratified by age, this association appeared to be limited to adults aged 35–52 years. After stratified by gender, except for Pb and Cd, we observed that blood Se showed a dose-dependent association with SFHL in men. In women, only Cd showed a dose-dependent association with speech and high-frequency hearing loss. Hearing loss was positively associated with blood levels of Pb and Cd. Additionally, our study provided novel evidence suggesting that excessive Se supplement would increase SFHL risk in men.

A negative association between blood Pb level (BPbL) and vitamin D metabolites in occupationally exposed populations has been reported, but data from the general population are scarce. Furthermore, the association between BPbL and vitamin D binding protein (DBP) and free 25-hydroxyvitamin D (25(OH)D) has not been reported. We investigated the association of BPbL with DBP, total and free 25(OH)D in healthy adolescents (n 1347; age range 11–16 years) cross-sectionally selected from all Governorates of Kuwait, utilising multi-stage cluster random sampling. Pb in whole blood was analysed by inductively coupled plasma MS, and DBP with ELISA. Plasma 25(OH)D was analysed by LC-MS/MS, and free 25(OH)D was calculated utilising the levels and binding affinities of DBP and albumin for 25(OH)D. DBP was positively associated with BPbL (β = 0·81; 95 % CI 0·14, 0·22; P < 0·001). A negative association between BPbL and total 25(OH)D was non-significant (P = 0·24) when BPbL was used as a continuous variable but was significant when used as quartiles (P = 0·02). The negative association between BPbL and free 25(OH)D was significant whether BPbL was used as continuous, as quartiles or as cut-off point of <5 µg/dl (0·24 µmol/l). In multinomial logistic regression, the odds of vitamin D insufficiency and deficiency were more than two-fold higher in the upper quartiles of BPbL compared with the lowest quartile. The negative correlation of BPbL with free 25(OH)D was more robust than its correlation with total 25(OH)D. Future studies must consider the levels of DBP when assessing the association between Pb and vitamin D metabolites.

Kufahrite, PtPb, is a new mineral (IMA2020-045) from the Ledyanoy Creek placer, Koryak Highlands, Russia. The mineral was found in isoferroplatinum (Pt3Fe) grains extracted from a heavy-mineral concentrate, together with tetraferroplatinum (PtFe), tulameenite (Pt2FeCu), native iridium, hollingworthite (RhAsS) and Cr-rich spinel. Kufahrite occurs as part of alteration rims which are formed together with tetraferroplatinum after isoferroplatinum, or as grains up to 150 μm in size. According to powder X-ray diffraction analyses kufahrite is isotypic to its synthetic analogue, it is hexagonal and crystallises in space group P63/mmc adopting the nickeline structure type. Its unit-cell parameters are: a = 4.2492(6) Å; c = 5.486(6) Å; V = 85.78 Å3 and Z = 2. The calculated density is 14.80 g/cm–3. The strongest diffraction lines are [d, Å (I, %) (hkl)]: 3.052 (80) (101), 2.197 (100) (102), 2.125 (28) (110), 1.747 (18) (210), 1.528 (35) (202), 1.240 (18) (212) and 0.958 (22) (312). The Vickers hardness is 295 kg/mm2 (range 262–320, n = 5), corresponding to a Mohs hardness of 4. The empirical formula of kufahrite, calculated from a mean value of 23 electron-microprobe analyses is (Pt0.94Rh0.04)Σ0.98(Pb0.83Sb0.19)Σ1.02. The name (pronounced as [ku fa rait]) honours Fahrid Shakirovitch Kutyev (1943‒1993), a geologist from the Institute of Volcanology of USSR Academy of Sciences, who played a key role in the discovery of the Koryak–Kamchatka Platinum Belt, including the Ledyanoy Creek placer platinum deposit, where the new mineral has been discovered.

High-resolution analysis of the ice core from Colle Gnifetti, Switzerland, allows yearly and sub-annual measurement of pollution for the period of highest lead production in the European Middle Ages, c. AD 1170–1220. Here, the authors use atmospheric circulation analysis and other geoarchaeological records to establish that Britain was the principal source of that lead pollution. The comparison of annual lead deposition at Colle Gnifetti displays a strong similarity to trends in lead production documented in the English historical accounts. This research provides unique new insight into the yearly political economy and environmental impact of the Angevin Empire of Kings Henry II, Richard the Lionheart and John.