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.

Tennantite-(Cd), Cu10Cd2As4S13, was approved as a new mineral species from the Berenguela mining district, Pacajes Province, La Paz, Bolivia. It occurs as black metallic anhedral grains, up to 1 mm across, associated with baryte, montmorillonite and secondary Cd-sulfates (aldridgeite, niedermayrite and voudourisite). In reflected light, tennantite-(Cd) is isotropic and grey with brownish tints. Reflectance data for the four COM wavelengths in air are [λ (nm): R (%)]: 470: 30.0; 546: 30.1; 589: 28.2; and 650: 25.8. Electron microprobe analysis gave (in wt.% – average of 11 spot analyses): Cu 40.56(32), Ag 0.05(5), Fe 0.04(1), Zn 1.91(63), Cd 11.32(1.09), Hg 0.04(7), As 19.04(43), S 26.78(30), total 99.74(53). On the basis of ΣMe = 16 atoms per formula unit (apfu), the empirical formula of tennantite-(Cd) is Cu9.98Ag0.01Cd1.57Zn0.46Fe0.01As3.97S13.05. Tennantite-(Cd) is cubic, I$\bar{4}$3m, with unit-cell parameters a = 10.3088(2) Å, V = 1095.53(6) Å3 and Z = 2. Its crystal structure was refined by single-crystal X-ray diffraction data to a final R1 = 0.0152 on the basis of 359 unique reflections with Fo > 4σ(Fo) and 22 refined parameters. Tennantite-(Cd) is isotypic with other tetrahedrite-group minerals. Its crystal-chemistry is discussed and previous findings of Cd-rich tetrahedrite-group minerals are briefly reviewed.

The development of non-toxic and inexpensive materials for arsenic removal is required due to water sources being polluted by arsenic in many countries around the world. The main aim of this study was to characterise the capacity and behaviour of Mg/Fe layered double hydroxides/biochar [Magnesium/Iron-Layered Double Hydroxide (Mg/Fe-LDH)] composite for arsenate adsorption from solution. Apple tree pruning residues were used to produce biochar at 500 °C under oxygen-limited atmosphere. Mg/Fe-LDH-biochar was synthesised using a spontaneous in situ co-precipitation method. Batch experiments were used for the assessment of the kinetics, isotherms, and the effects of initial solution pH (4, 6, 8, and 10), ionic strength (0.01, 0.1, and 0.2 mol L−1), and co-occurring anions (carbonate and phosphate) on the arsenate removal. Scanning electron microscope images showed Mg/Fe-LDH were loaded on the biochar porous structure, and X-ray diffraction analysis affirmed the presence of crystalline LDH minerals in Mg/Fe-LDH-biochar. Surface modification of biochar by Mg/Fe-LDH increased the maximum arsenate adsorption capacity (3.6 mg g−1) ten times compared to unmodified biochar (0.35 mg g−1). Arsenate removal capacity increased from 4.2 % to 54.2 % with modification of biochar by Mg/Fe-based LDH. Kinetic studies indicated that >90 % of Mg/Fe-LDH-biochar arsenate adsorption from a starting concentration of 10 mg L−1 occurred in the first 120 min. Pseudo-second order and Langmuir models described well the kinetics and isotherm of arsenate adsorption by biochar and Mg/Fe-LDH-biochar. Mg/Fe-LDH-biochar showed maximum arsenate removal capacity at pH 6. Increasing solution ionic strength and the presence of phosphate and carbonate anions suppressed arsenate removal by Mg/Fe-LDH-biochar. In summary, surface modification of biochar using Mg/Fe-LDH produced a potentially more cost-effective, locally available, reusable, and non-toxic arsenic adsorbent for decontamination of surface- and groundwater.

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.

Tennantite-(Cu), Cu12As4S13, was approved as a new mineral species from the Layo epithermal deposit, Castilla Province, Arequipa Department, Peru, where it occurs as black metallic anhedral grains, up to 0.1 mm across, replacing enargite and associated with chalcopyrite and vinciennite. In reflected light, tennantite-(Cu) is isotropic, grey with a bluish shade. Reflectance data for the four COM wavelengths in air are [λ (nm): R (%)]: 470: 29.1; 546: 28.4; 589: 27.4; and 650: 25.0. Electron microprobe analysis for holotype material gave (in wt.% – average of 10 spot analyses): Cu 49.32(27), Fe 2.20(12), Zn 0.09(2), Sn 0.03(5), As 19.45(43), Sb 1.94(10), Te 0.02(5), S 27.75(43), total 100.80(20). On the basis of (As + Sb + Te) = 4 atoms per formula unit (apfu), the empirical formula of tennantite-(Cu) is (Cu11.27Fe0.57Zn0.02)Σ11.86(As3.77Sb0.23)Σ4.00S12.57. Tennantite-(Cu) is cubic, I$\overline 4$3m, with unit-cell parameters a = 10.1710(10) Å, V = 1052.2(2) Å3 and Z = 2. Its crystal structure was refined by single-crystal X-ray diffraction data to a final R1 = 0.0178 on the basis of 263 unique reflections with Fo > 4σ(Fo) and 24 refined parameters. Tennantite-(Cu) is isotypic with other tetrahedrite-group minerals. Previous findings of tennantite-(Cu) are reported and some nomenclature issues, related to the Fe and Cu oxidation states, are discussed. At the Layo epithermal deposit, tennantite-(Cu) is the result of the replacement of enargite under decreasing $f_{{\rm S}_ 2}$ conditions.

Tennantite-(Hg), Cu6(Cu4Hg2)As4S13, was approved as a new mineral species (IMA2020-063) from the Lengenbach quarry, Imfeld, Binn Valley, Canton Valais, Switzerland. It was identified as an aggregate of black metallic tetrahedral crystals, less than 0.1 mm in size, intimately associated with sinnerite, and grown on realgar. In reflected light, tennantite-(Hg) is isotropic, grey in colour, with creamy tints. Minimum and maximum reflectance data for COM wavelengths in air are [λ (nm): R (%)]: 470: 29.1; 546: 29.1; 589: 28.5; 650: 27.7. Electron microprobe analysis gave (in wt.% – average of 7 spot analyses): Cu 32.57(42), Ag 6.38(19), Tl 0.29(14), Zn 0.04(5), Hg 17.94(2.27), Pb 0.70(51), As 17.83(61), Sb 0.34(8), S 24.10(41), total 100.19(1.04). The empirical formula of the sample studied, recalculated on the basis of ΣMe = 16 atoms per formula unit, is (Cu4.69Ag1.04Tl0.03)Σ5.76(Cu4.35Hg1.58Pb0.06Zn0.01)Σ6.00(As4.20Sb0.05)Σ4.25S13.26. Tennantite-(Hg) is cubic, I$\overline 4$3m, with a = 10.455(7) Å, V = 1143(2) Å3 and Z = 2. The crystal structure of tennantite-(Hg) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.0897 on the basis of 214 unique reflections with Fo > 4σ(Fo) and 22 refined parameters. Tennantite-(Hg) is isotypic with other members of the tetrahedrite group. Mercury is hosted at the tetrahedrally coordinated M(1) site, in accord with the relatively long M(1)–S(1) distance (2.389 Å), similar to that observed in tetrahedrite-(Hg). Minor Ag is located at the triangularly-coordinated and split M(2) site. Other occurrences of tennantite-(Hg) are briefly reviewed and the Lengenbach finding is described within the framework of previous knowledge about the Hg mineralogy at this locality.

The new mineral, zvěstovite-(Zn), ideally Ag6(Ag4Zn2)As4S13, was found in quartz–baryte gangue at the mine dump of the abandoned small deposit of Zvěstov, central Bohemia, Czech Republic. Zvěstovite-(Zn) is associated with tennantite-(Zn), tetrahedrite-(Zn), argentotennantite-(Zn), acanthite and supergene azurite and malachite. The new mineral occurs as rare relic anhedral grains rimmed by acanthite, up to 100 μm in size. Zvěstovite-(Zn) is grey, Mohs hardness is ca. 3½–4, in agreement with other members of the tetrahedrite group; the calculated density is 5.16 g.cm–3. In reflected light, zvěstovite-(Zn) is grey with a greenish tint, without bireflectance, pleochroism or anisotropy. Deep red internal reflections are ubiquitous. Reflectance values of zvěstovite-(Zn) in air (R%) are: 28.5 at 470 nm, 26.9 at 546 nm, 25.5 at 589 nm and 23.8 at 650 nm. The empirical formula for zvěstovite-(Zn), based on electron-microprobe analyses (n = 4), is Ag6.27[(Ag3.90Cu0.38)Σ4.28(Zn1.60Fe0.09Cd0.03)Σ1.72]Σ6.00(As2.26Sb1.48)Σ3.74S12.50. The ideal formula is Ag6(Ag4Zn2)As4S13, which requires (in wt.%) Ag 56.01, Zn 6.79, As 15.56 and S 21.64, total 100.00. Zvěstovite-(Zn) is cubic, I$\bar{4}$3m, with unit-cell parameters: a = 10.850(2) Å, V = 1277.3(8) Å3 and Z = 2. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I) (hkl)] are: 3.1321(100) (222), 2.7125(21) (400), 1.9809(11) (521), 1.9180(31) (440) and 1.6357(15) (622). According to the single-crystal X-ray diffraction data (Robs = 0.051), the crystal structure of zvěstovite-(Zn) agrees with the general features of the members of the tetrahedrite group. Zvěstovite-(Zn) is named after its type locality, Zvěstov; the suffix indicates the dominant divalent C-constituent, according to the approved nomenclature of the tetrahedrite group. It is the As-isotype of rozhdestvenskayaite-(Zn). The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2020-061).

We report on the crystal structures of three novel synthetic SrM-arsenates (M = Ni and Fe3+), isostructural or structurally related to the minerals from tsumcorite, carminite and brackebuschite groups. They were synthesised under mild hydrothermal conditions and further characterised using single-crystal X-ray diffraction (SXRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and Raman spectroscopy. SXRD and SEM-EDS yielded formulae: (I) SrNi2(AsO4)2⋅2H2O, (II) Sr1.4Fe3+1.6(AsO4)2(OH)1.6 and (III) SrFe3+(AsO4)(AsO3OH). All three structures are built up of slightly distorted MO6 octahedra and AsO4 tetrahedra that are linked by Sr2+ with different coordination geometries and hydrogen bonds. I represent a basic structure type typical for tsumcorite-group minerals (space group C2/m) while II has a new intermediate structure between carminite, PbFe3+2(AsO4)2(OH)2 and arsenbrackebuschite, Pb2Fe3+(AsO4)2(OH) (s.g. Pm). III is triclinic and adopts a new structure-type (s.g. P$\bar{1}$). The structure of I is built up of infinite linear edge-sharing NiO4(OH2)2 octahedral chains, extending along [010] and linked by AsO4 tetrahedra, SrO8 polyhedra and hydrogen bonds. The structure of II is characterised by the carminite-like FeO4(OH)2 octahedral chains and Edshammar-polyhedral chains, which involves SrO11 coordination polyhedra similar to that of PbO11 in arsenbrackebuschite. Both chains in II are aligned parallel to the b axis of the monoclinic unit cell and connected together by the arsenate AsO4 tetrahedra, SrO8 polyhedra and the hydrogen-bonding network. The compound III has a new type of crystal structure based on the unusual corrugated octahedral–tetrahedral-quadruple chains. These are made up of a central double-sided chain linked to two single-sided chains into a quadruple chain extended along the a axis. The chains in III are built up of FeO6 octahedra and AsO4 tetrahedra further linked to each other by shared vertices. The quadruple chains are interconnected by additional AsO4 tetrahedra forming a heteropolyhedral 3D open framework. Strontium atoms are situated in the two channels. The structural connections to related minerals and inorganic compounds are discussed.

During the late nineteenth and early twentieth centuries, arsenic was used as an embalming agent in the United States. In 1996, Konefes and McGee brought the potential danger of arsenic poisoning during excavation to the attention of archaeologists. They developed methodology that was later refined by the present authors. This article discusses the history of arsenic as an embalming agent, explores socioeconomic and demographic factors that might suggest the presence of arsenic in certain burials, and presents methods for testing arsenic in archaeological contexts. We also discuss environmental impact mitigation considerations and review examples of arsenic testing in archaeological contexts.

The transformation of schwertmannite to goethite was studied by ageing one synthetic and five natural schwertmannites in water at room temperature. Additionally, one synthetic and two natural schwertmannites were kept at variable pH (2, 4, 6 and 8). After one year, only the synthetic sample and one natural schwertmannite had transformed to goethite. However, the oxalate solubility of Fe and trace elements in all the samples decreased, whereas the total Fe/S ratios and specific surface areas of all samples increased. Arsenic and organic matter appeared to suppress the schwertmannite-to-goethite phase transformation. At pH 2, synthetic schwertmannite fully-transformed to goethite, but at pH 4–6 only minor transformation occurred. Depending on pH, many trace elements were released into solution during ageing of the natural schwertmannites. In general, Co, Mn, Zn and Si were released to solution, whereas As was enriched in the remaining iron oxide fraction. Al was dissolved at pH <4.

Among the arsenic species in the environment, arsenate predominates under oxidizing conditions in soils and waters. The adsorption of As(V) by some natural Fe oxyhydroxides and clay minerals and synthetic Al(OH)3 and FeOOH has been studied. The results show a very high As(V) adsorption capacity on both synthetic Al hydroxide (122 mg/g at pH: 5) and Fe oxyhydroxide (76 mg/g at pH 5). This adsorption capacity is pH dependent and shows maximum values at ∼pH 4. The application of these adsorbents to arsenic immobilization in the remediation process of two polluted mining soils with some differences in their physicochemical characteristics has also been studied. The best results were obtained when synthetic Al(OH)3 and FeOOH were used; these materials decreased the water-extractable fraction of As by 55–79% for one soil and by nearly 100% for the other soil, the latter with higher pH and Eh values.

Degradation of contaminant hydrocarbons in groundwater by microbially mediated oxidation, linked to the reduction of electron acceptors, is fundamental to the strategy of ‘monitored natural attenuation’ (MNA) for oxidizable hydrocarbons, which is increasingly being adopted at polluted aquifer sites throughout Europe and North America. Commonly, oxygen is depleted and following the reduction of nitrate, solid-phase Fe oxides become the dominant electron acceptors. Arsenic, associated with Fe and Mn oxides in soils and sediments, may therefore be mobilized to groundwater and pose an additional threat to environmental receptors. In a pilot study of three aquifers in England, we have examined the extent to which arsenic is released to groundwater under Fe(III)-reducing conditions imposed by contaminant hydrocarbons. Results show that arsenic is locally mobilized in the Chalk to <10 μg/1, in Quaternary gravels to 70 μg/1 and in the Triassic sandstones to 160 μg/1. At the Chalk and Quaternary gravels sites arsenic mobilization is demonstrably linked to reduction of Fe- and Mn-oxides. This is not so at the Triassic sandstone site, where release of arsenic is related to elevated bicarbonate alkalinity. Redox-driven arsenic mobilization at other Triassic sandstone locations is possible. Further work is required on the solid-phase sources of arsenic in the aquifers, and to relate the hydrochemical observations to groundwater hydraulic conditions.

Understanding the biogeochemical behaviour of arsenic in the weathering and shallow subsurface environment depends critically upon determining the nature and distribution of the chemical species present in natural waters. To this end, coupled ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP-MS) is widely used, though species fractionation during ultrasonic nebulization, and matrix-dependent ionization in the plasma are analytical issues that need to be addressed. Hexapole collision cell technology is shown to be effective in suppressing chloride-based polyatomic interferences. Irrespective of the analytical technique used, As(III)/As(V) ratios of natural waters may change substantially during storage due to (1) differential adsorption of arsenic species on hydrated ferric oxides (HFOs); and (2) microbial activity. A wide range of apparently contradictory speciation changes observed by various workers can be rationalized in terms of the differences of microbial consortia present in different water samples. Arsenic speciation in certain water types can be stabilized for days or even weeks by combined filtration, acidification and refrigeration whilst the addition of EDTA and the use of 0.1 mm filters is indicated for iron-rich waters and waters with high activities of redox-active bacteria, respectively. Although the use of hydrochloric acid has been reported elsewhere as resulting in the apparent oxidation of As(III), we show that for certain water types it acts as an extremely effective preservative of arsenic speciation.

Daliranite, ideally PbHgAs2S6, a new sulphosalt from the Zarshouran Au-As deposit, Takab region, Iran, occurs as a rare sulphosalt species at the Carlin-type Zarshouran Au-As deposit North of the town of Takab in the Province of West Azarbaijan, Iran. The new species is associated with orpiment, rarely with galkhaite, hutchinsonite and cinnabar. The strongly silicified matrix of the specimens has veinlets of sphalerite, with rare inclusions of galena and various (Cu)-Pb-As(Sb) sulphosalts. Daliranite occurs as matted nests of acicular and flexible fibres up to 200 μm in length and a width less than a few μm. The colour is orange-red with a pale orange-red streak and the lustre is adamantine. The mineral is transparent and does not fluoresce. The Mohs hardness is <2. Electron microprobe analyses give the empirical formula Pb0.95Tl0.01Hg1.04As2.10S5.91, ideally PbHgAs2S6, a new sulphosalt from the Zarshouran Au-As deposit, Takab region, Iran; the calculated density is 5.93 g cm–3. Unit-cell parameters were determined by an electron-diffraction study and refined from X-ray powder data. Daliranite is monoclinic primitive with a = 19.113(5) Å, b = 4.233(2) Å, c = 22.958(8) Å, β = 114.78(5)°, V = 1686.4 Å3 and Z = 8, a:b:c = 4.515:1:5.424, space group P2, Pm or P2/m. The strongest X-ray powder-diffraction lines [d in Å, (I), (hkl)] are: 8.676, (80), (200); 4.654, (50), (401); 3.870, (40), (211); 3.394, (50), (113); 3.148, (40b), (602); 2.892, (50), (600); 2.724, (100), (703); 2.185, (50), (319). The formula shows a sulphur excess which may correspond to S—S bonding (persulphide). The new sulphosalt is a late phase in the crystallization sequence, and was formed after orpiment, contemporaneously with quartz II, at a temperature between 157 and 193°C. The name honours Dr Farahnaz Daliran (University of Karlsruhe, Germany) in recognition of her outstanding contributions to research on ore deposits, especially Au, Zn and Fe, in Iran.

The crystal structure of sarmientite, Fe23+ (AsO4)(SO4)(OH)·5H2O, from the type locality (Santa Elena mine, San Juan Province, Argentina), was solved and refined from in-house powder diffraction data (CuKα1,2 radiation). It is monoclinic, space group P21/n, with unit-cell dimensions a = 6.5298(1), b = 18.5228(4), c = 9.6344(3) Å, β = 97.444(2)º, V = 1155.5(5) Å3, and Z = 4. The structure model was derived from cluster-based Patterson-function direct methods and refined by means of the Rietveld method to Rwp = 0.0733 (X2 = 2.20). The structure consists of pairs of octahedral-tetrahedral (Fe−As) chains at (y,z) = (0,0) and (½,½), running along a. There are two symmetry-independent octahedral Fe sites. The Fe1 octahedra share two corners with the neighbouring arsenate groups. Both individual chains are related by a symmetry centre and joined by two symmetry-related Fe2 octahedra. Each Fe2 octahedron shares three corners with double-chain polyhedra (O3, O4 with arsenate groups; the O8 hydroxyl group with the Fe1 octahedron) and one corner (O11) with the monodentate sulfate group. The coordination of the Fe2 octahedron is completed by two H2O molecules (O9 and O10). There is also a complex network of H bonds that connects polyhedra within and among chains. Raman and infrared spectra show that (SO4)2− tetrahedra are strongly distorted.

Mineralogical-chemical techniques (XRD, SEM/EDX, WDXRF) and a sequential selective extraction procedure were applied to mine-waste materials and stream sediments from the Baccu Locci stream catchment (Sardinia, Italy) affected by serious As contamination as a consequence of past mining. Results indicate that solid-state speciation of As is mainly dominated by the presence of Fe(III) hydroxides (arsenical ferrihydrites with various Fe/As molar ratios) occurring as coatings of silicate grains, in which As is contained as sorbed or co-precipitated species. Scorodite (FeAsO4·2H2O) is common too, whereas arsenopyrite is generally subordinate but, owing to its relatively rapid oxidation, environmentally significant. Moreover, some unidentified arsenates of Ca-Fe or K-Fe were also detected. Arsenic contained in these phases is slowly, but continuously, released in relatively small amounts through three main mechanisms: (1) oxidation of residual arsenopyrite to scorodite; (2) decomposition of scorodite into a hydroxide or oxide of Fe(III); (3) desorption/release from Fe(III) hydroxides. Decomposition of the unidentified arsenates is also probable, e.g. Ca-Fe arsenate → calcite + Fe(III) hydroxide + As release. The flotation tailings are widely scattered and distributed in the middle–lower Baccu Locci stream catchment, and represent the most dangerous As-generating contamination source in the study area.