Cerussite Research Articles

Occurrence and sources of lead in private wells, Sturbridge, Massachusetts

Lead (Pb) occurrence and sources and aqueous geochemistry were assessed in private wellhead and tap water at a targeted area of concern for possible exceedances and at a control area in the same geologic formation, and in wells at a nearby landfill in south-central Massachusetts (MA). Total Pb concentrations were below the U.S. Environmental Protection Agency (USEPA) Action Level of 15 μg/L in all samples, and about 6% of unfiltered samples contained Pb concentrations that exceeded 1.0 μg/L. Pb concentrations were higher under conditions that are acidic and oxic (pH ≤ 6.5 and dissolved oxygen [DO] ≥ 2 mg/L), in which minerals that could sequester lead or manganese typically are undersaturated, and adsorption by hydrous ferric oxide is limited. Under more neutral to alkaline conditions, the precipitation of Pb in solid solution series minerals such as (Ca,Pb)CO3 and (Ba,Pb)SO4−2, and adsorption by amorphous ferric hydroxides, could limit Pb solubility in the bedrock aquifer or in the plumbing. The low Pb concentrations and the absence of distinctive Pb and strontium (Sr) isotope ratio patterns in samples indicate that a nearby landfill is not likely a significant Pb source. Dissolved concentrations of Pb, copper (Cu), and zinc (Zn) in tap samples were significantly greater than those in wellhead samples, indicating that some Pb is derived from plumbing. Wellhead or tap samples with the highest Pb concentrations also had the greatest corrosivity potential based on the calcite saturation index and the PPGC (Potential to Promote Galvanic Corrosion) and supports the premise that Pb concentrations in tap samples were derived partly from corrosion of plumbing. Concentrations of other constituents, including arsenic (As), uranium (U), Sr, boron (B), and lithium (Li) were not statistically different between the tap and wellhead samples but, apart from Sr, all were statistically higher in the control area than in the target area. This variation in constituent concentrations suggests geochemical variation within the host Paxton Formation, possibly related to faulting and contact with the Ayer granite east of the control area.

Lead/lead-alloy as a corrosion-resistant outer layer packaging material for high level nuclear waste disposal

Safe disposal of high-level nuclear waste (HLW) is a challenging problem world-wide. Corrosion-resistant waste packages constitute a key component of a multiple barrier system for waste isolation. Metallic copper has been proposed as an outer layer material for a waste package. However, a concern has been raised regarding potential copper corrosion induced by hydrogen sulfide in a reducing disposal environment. We here demonstrate that lead/lead-alloy materials could be an excellent alternative material for waste package outer layers, owing to their corrosion resistance (especially to hydrogen sulfide attack) and radiation-shielding capability. Our long-term (∼800 days) corrosion experiments show that lead could be passivated by a dense layer of sparingly soluble corrosion products, cerussite (PbCO3) and tarnowitzite (Ca,Pb)CO3, in contact with carbonate-bearing groundwaters. If needed, the carbonate concentration in a repository can be conditioned by adding carbonate materials such as calcite or hydromagnesite as a buffer material component to ensure cerussite precipitation. With its low solubility (<10–6 mol•kg−1), cerussite is more favored to form over galena (PbS) in a typical disposal environment. Thus, the issue of sulfide-induced metal corrosion as that happens to copper can potentially be eliminated. Furthermore, using lead/lead alloy will provide excellent radiation shielding for waste package transportation and repository operation.

مطالعات کانی سازی، ژئوشیمی، سیالات درگیر و ایزوتوپ پایدار گوگرد کانسار Cu-Zn-As باقرق با سنگ میزبان کربناته (شمال شرق انارک)

کانسار Cu-Zn-As باقرق در شمال شرق شهر انارک و در استان اصفهان قرار دارد. کانی‌سازی به‌صورت دیرزاد، ماهیت چینه‌کران و بافت و ساخت پرکننده فضای خالی در سنگ میزبان کربناتی رخداده است. کانی‌شناسی بخش درون‌زاد شامل کالکوسیت، کالکوپیریت، پیریت، اسفالریت، گالن، انارژیت، باریت و کلسیت و کانیهای بخش برون‌زاد شامل مالاکیت، آزوریت، کوولیت، کریزوکولا، کالکوسیت، سروزیت، اسمیت‌زونیت، مس طبیعی، هماتیت، گوتیت و لیمونیت می‌باشد. سنگ میزبان کربناتی در اطراف زون‌های کانه‌دار متحمل دگرسانیهای دولومیتی‌شدن و کلسیتی‌شدن شده است. مس به‌عنوان عنصر اصلی ذخیره (با میانگین 28/20 درصد وزنی) و پس از آن عناصر روی (با میانگین تقریبی 1 درصد وزنی) و آرسنیک (با میانگین تقریبی 1 درصد وزنی) می‌باشند. مطالعات سیالات‌درگیر روی کانی باریت نشان می‌دهد سیال کانه‌دار سولفیدی دارای محدوده دمای همگن شدن بین 259 تا 354 درجه سانتی‌گراد و میزان شوری بین 8 تا 13 درصد وزنی معادل NaCl می‌باشد. سیال کانه‌دار در مراحل پایانی کانی‌سازی با آبهای جوی دچار اختلاط شده و فاز تأخیری غیر سولفیدی کلسیتی با محدوده دمای نسبتا پایین ‌(78 تا 112 درجه سانتی‌گراد) و درجه شوری پایین (بین 3 تا 6 درصد وزنی معادل NaCl) را تشکیل داده است. محدوده مقادیر 34Sδ کانی‌ باریت کانسار باقرق بین 13+ تا 14+ در هزار بوده در حالی‌که محاسبه مقدار 34Sδ مربوط به سیال کانه‌دار پس از تصحیح دمایی بین 7- تا 8- در هزار به‌دست آمد. منشأ گوگرد باقرق با توجه به شباهت ایزوتوپ باریت با سولفات‌های دریایی کرتاسه، احتمالا از لایه‌های تبخیری این دوره زمانی تأمین شده است. این سولفا‌ت‌ها توسط فرآیند‌های ترموشیمیایی به‌صورت بخشی به گوگرد احیایی با مقدار ایزوتوپی سبک‌تر (حدود 21 در هزار) تبدیل و جهت ته‌نشست سولفیدها مورد استفاده قرار گرفته است. کانسار باقرق با توجه به خصوصیاتی همچون سنگ میزبان کربناته، غیاب فعالیت آذرین، بافت پرکننده فضای خالی، دگرسانی دولومیتی،کانی‌شناسی، ژئوشیمی ماده‌معدنی (وجود As و Sb بالا و عدم حضور Bi)، داده‌های دماسنجی و مقادیر ایزوتوپ گوگرد، شباهت زیادی با کانسارهای مس با سنگ میزبان کربناته در افریقا و به‌ویژه نوع سومب (Tsumeb) در نامیبیا نشان می‌دهد. کانسار باقرق احتمالا مرتبط با سیالات دگرگونی آزاد شده در حین فازهای کوه‌زایی مرتبط با بسته‌شدن اقیانوس نئوتتیس می‌باشد.

Redistribution of Pb during transformation of monohydrocalcite to aragonite

Monohydrocalcite was transformed to aragonite in the presence of Pb in solution to understand the Pb redistribution mechanisms and kinetics during the transformation. Monohydrocalcite (Ca0.98Mg0.02CO3·1.00H2O) was synthesized, and along with Pb stock solution, added to a buffer solution; batch sorption experiments were carried out (i) at different initial-Pb concentrations ranging from 1 to 100μM (1–30 and 50–100μM, referred to as low and high initial-Pb concentrations, respectively) for 24h and (ii) at different reaction time for 1–24h at 1 and 100μM of the initial Pb concentrations. The CO32− concentration (24.4meq/L), pH (9.50) and temperature (25°C) were kept constant within experimental errors throughout the experiments. The transformation of monohydrocalcite was completed in 24h, probably in 15h, at the low initial-Pb concentrations but not even in 24h at the high initial-Pb concentrations, suggesting that the aqueous Pb concentration affects the rates of dissolution of monohydrocalcite and/or nucleation and crystal growth of aragonite, and thus, the transformation rate. Aragonite was shortly formed as monohydrocalcite was dissolved and almost all amount of Ca dissolved from monohydrocalcite formed aragonite. ~90–96% of the initial Pb was adsorbed onto monohydrocalcite before the transformation started, and >95% of the initial Pb was distributed in solid phases at any elapsed time of the reaction and at any initial-Pb concentrations, indicating that the Pb redistribution rate was as fast as the transformation rate of monohydrocalcite. Pb carbonate (possibly hydrocerussite) was formed at the high initial-Pb concentrations but not at the low initial-Pb concentrations. The precipitation rate of the Pb carbonate is slower than the transformation rate of monohydrocalcite. The Pb sorption on aragonite occurred dominantly by incorporation. After the transformation, accordingly, almost all Pb was incorporated in aragonite at the low initial-Pb concentrations, and in aragonite and Pb carbonate at the high initial-Pb concentrations. The incorporation of Pb in aragonite is well explained by the formation of (Ca,Pb)CO3 solid-solution. The Pb redistribution during transformation of monohydrocalcite to aragonite revealed by the present study will give a deeper understanding of trace element transport at the Earth's surface when the transport is accompanied by mineral transformation.

Polymetallic mineralization of the Boranja orefield, Podrinje Metallogenic District, Serbia: zonality, mineral associations and genetic features

In the Serbo-Macedonian Metallogenetic Province, which is a part of the Alpine metallogenic unit, the ore deposits lie in number geotectonic units; they embrace part of the Vardar Zone, Serbo-Macedonian massif, and a small part of the Dinarides. This metallogenic province has been delineated mostly by reference to the Neogene metallogeny, related predominantly to granodiorite magma. These deposits include the most significant Pb-Zn and Sb deposits in Serbia, as well as smaller Bi, Mo, Cu, Fe, Sn, Au and minor U, W and Hg deposits. The Podrinje Metallogenic District belongs to the Serbo-Macedonian Metallogenetic Province. Smaller metallogenic provinces are isolated within the scope of the following orefields: Cer (Northwest Serbia), Boranja (West Serbia), and Srebrenica (East Bosnia & Herzegovina). Polymetallic deposits in the Boranja orefield are genetically related to the emplacement of a Tertiary granodiorite complex. It consists primarily of a large number of sulfide deposits with Pb-Zn, and Sb; with subordinate Cu, As, Bi and Ag. Among them, the presence of small magnetite deposits, connected to the pyrometasomatic (skarn) stage is significant. Skarns are of calcic type, and were formed along contacts of Triassic limestones and quartz diorites. Ore minerals are similar among the various types of orebodies in the Boranja orefield and consist of sulfides (pyrrhotite, pyrite, marcasite, chalcopyrrhotite, chalcopyrite, cubanite, mackinawite, valleriite, covelline, chalcocite, bismuthinite, molybdenite, sphalerite, mercurian sphalerite, greenockite, galena, arsenopyrite, stibnite, duranusite, realgar, orpiment, cinnabar, metacinnabar); sulfosalts (bursaite, cannizzarite, cosalite, aikinite, ustarasite, tetradymite, ferrian tetrahedrite, argentian tetrahedrite, pyrargyrite, diaphorite, freieslebenite, schirmerite, fizelyite, stannite, jamesonite, boulangerite, bournonite, As-bournonite, falkmanite, zinkenite, fuloppite, robinsonite, plagionite, twinnite, geocronite, gratonite); telluride (calaverite); native metals and alloys (gold, silver, electrum, bismuth, arsenic); oxides and complex-oxides (magnetite, hematite, rutile, anatase, scheelite, powellite, valentinite, senarmontite, kermesite, adamite, arsenolite); and gangue minerals (silicates, carbonates, fluorite, calcite, siderite, Mn-Zn siderite, fluorite, apatite, barite, dolomite, anglesite, cerussite, smithsonite, otavite, malachite, azurite, scorodite, quartz, limonite, organic matter). Minerals of the titled orefield were formed in several successive stages, which together correspond to a unique cycle of mineralization that is genetically related to the subvulcanic-plutonic intrusion of the Neogene-aged magmatic Boranja complex. Mineral associations, which have spatial-zonal arrangement, are rhythmically developed from the Tertiary granodiorite of Boranja to outside surroundings: A) Fe-Cu(Bi) belt → B) Pb(Ag)-Zn belt → C) Sb(As) belt → D) CaF 2 (Pb-Zn) belt.

THE CONSEQUENCES OF FEMALE RATS CHRONIC EXPOSURE TO LEAD ACETATE ON THE BIOMARKERS EMPHASIZING THE HORMONAL DISRUPTING POTENTIAL OF THE REPRODUCTIVE FUNCTION FOR IN VIVO EVALUATION

Lead is a metal which is naturally found in earth crust [4], in mineral from: blue lead, anglesite, cerussite, mimetit, linarit, vanadinite and wulfenite [10, 15]. The products that contain lead are: paints, accumulators, ceramics, shots, gun bullets [5, 10, 14], defense system against X rays and radiations generally [11, 13], pigments, insecticides (lead arsenate), enamels, glass [7, 11], linoleum etc. The are few data referring to lead impact on reproductive system, however, it had been underlined the fact that lead accumulation in ovaries, even less in chronic supply conditions, determines the follicle genesis disturbance, resulting less primordial follicles and more atrezic follicles and also ovary cysts. The aim of the study was to evaluate lead reproductive toxicity for female rats. The concrete objectives were: evaluation of biological markers that emphasize the hormonal disrupting potential of reproductive function for in vivo evaluation (sexual hormones: FSH, LH, estradiole, progesterone, and testosterone)

Il porgetto di conservazione della cappella di Tas-Salvatur (Kalkara, Malta) : analisi diagnostiche

The origins of the Tas-Salvatur chapel go back to the 15th century, but historical events brought about demolitions (at the beginning of the Great Siege of 1565 by order of the Grand Master Jean Parisot de la Vallette, and during the uprising against the French in 1798), re-edifications (in 1670 by prior Fra Giovanni Bichi) and interventions over the ages. Inaccessible during past years to parishioners and completely abandoned, the whole chapel is at present the subject of a conservation project carried out by the Malta Center for Restoration within the Cottonera Rehabilitation Project. In the first phase of restoration works, several scientific analyses were performed in order to define the nature of constituent materials and to evaluate the causes and the effects of deterioration processes. Original polychrome layers and repainting were found on the statue of the Madonna with Child situated in the external niche, on the altar, on the overhanging frame and on the sepulchral monument located in the interior of the chapel. Optical microscopy (under visible and UV light), SEM-EDX and FT-IR analysis were carried out identify the painting materials, the remnants of external plastering layers on the facade and the internal ones. Most of the repainting layers are made of lead white (2 PbCO3 PbCO3 Pb(OH)2) and lithopone [BaSO4 + ZnS (ZnO)]. The frame was originally gilded with a guazzo technique and covered later on with several layers of paint. The sepulchral monument in memory of Fra Giovanni Bichi was originally covered with a reddish layer of ochre on stone, while the central framed medallion and the relief portrait of the deceased were gilded (a missione). Below, on the lion's head that forms the lower part of the coat of arms, a brilliant vermilion red (HgS) was revealed under the gray repainting layers. Distribution of salts in the external masonry was evaluated and quantitative data were obtained by means of IC analysis. Tests for the extraction of salts were performed on the lower part of the altar. Sulphatation processes were found where subflorescences of gypsum are the main cause of the loss of stone material (flaking).

Environmental mineralogy and geochemistry of waste dumps at the Pb(Zn)-Ag Bottino mine, Apuane Alps, Italy

The Bottino mine (Apuane Alps, Tuscany) had been exploited for silver and lead since at least Renaissance times. Detailed field work has led to the recognition of several mine dumps which differ in size, age, and types (rock waste dumps; jigging and handpicking wastes). In the dumps, the primary sulfides are sphalerite, galena, and pyrite ± variable amounts of chalcopyrite, pyrrhotite, arsenopyrite, and a wealth of other sulfides and sulfosalts. These mine- rals are associated with gangue quartz, white micas, chlorite, and carbonates, mostly of the siderite-magnesite and dolomite-ankerite series, whereas calcite is scarce. Supergene alteration led to the development of secondary mine- rals such as goethite, lepidocrocite, pyrolusite, cerussite, and clay minerals (kaolinite, montmorillonite, and vermi- culite). Two main types of supergene effects have been observed: (a) development in situ of pseudomorphic replacement of primary minerals, and (b) leaching and dissolution. Acid generation and metal release are mainly pro- duced by the replacement of pyrrhotite by iron hydroxides, the partial dissolution of siderite-magnesite carbonates, and the extensive dissolution/replacement of galena and sphalerite. Given the scarcity of calcite in the primary assem- blage, the most effective attenuators of acidity seem to have been dolomite-ankerite and siderite-magnesite. The mainly unpolluted character of the Bottino waters may be explained by a number of concurring factors, including the moderate volume of wastes, their overall coarse grain size, the low abundance of acid-producing phases (pyrite and pyrrhotite) relative to acid-consuming phases such as dolomite-ankerite, and the steep topography.

Equilibrium and spectroscopic studies of lead retention in smectite1

Heavy metal pollution of soils and water is a serious environmental problem. Sorption onto solid surfaces from aqueous solutions is an important process influencing transport and accumulation of heavy metals in the environment. Lead (Pb) sorption in smectite SWy‐2 was investigated by equilibrium sorption studies, coupled with spectroscopic methods. The isotherm and pH‐edge of lead sorption in the smectite were measured in batch experiments. The sorption isotherms under uncontrolled pH were best‐fitted with the Langmuir equation, while those with a fixed pH 5.5 were best‐fitted with the Freundlich equation. The pH‐edge of lead sorption shifted to a higher pH as the Pb concentration increased. The ionic strength only affected Pb sorption in the low pH range. The effects of associated nitrate and perchlorate anions were significant only for the Pb sorption at high Pb concentration (>2 mM). FTIR and XRD spectroscopies were performed with oriented clay samples. In the infrared spectra, apeak with a maximum near 1398 cm‐1 and a shoulder centered near 1470 cm‐1 was significant for the samples treated with >1 mM Pb at pH >5.6. This peak may be composed of several IR bands, including an OH bending band from Pb hydroxides and CO3 2‐ stretching bands from Pb carbonates. The basal spacing of Pb‐treated smectites increased with increasing Pb content in the clay and correlated well with the intensity of OH bending band (around 1621 cm‐1) of adsorbed water. The increase of basal spacing at low pH (pH <3.3) was poorly correlated with the intensity of water OH bending band. The comprehensive studies provided many evidences for revealing the structure of various lead complexes on clay surfaces.

On the meaning of the words cerussa and psimithium (psimythion).

On the meaning of the words cerussa and psimithium (psimythion).

Thermochemical Study of Cerussite

By using thermobalance to dissociate cerussite into lead monoxide in the air, it is shown that the following intermediate basic carbonates were produced : PbCO3→2PbO·PbCO3→11PbO·PbCO3→19PbO3·PbCO3→PbO., As the procedure was undertaken in CO2 gas, however, the following salts were produced by dissociation : PbCO3→PbO·PbCO3(or 3PbO·2PbCO3)→2PbO·PbCO3→PbO., This fact was quite true with the differential thermal analysis., By using the filament manometer, dissociation pressures of cerussite were measured., From the results thus obtained, the relations between the dissociation pressure and the temperature were expressed by the following equations, and the heats of dissociation (Q) and the dissociation temperatures (t) were calculated as follows., (I) log p=15., 52-7200/T, Q=-32930 cal/mol, t=296., 5°C (II) log p=13;69-7152/T, Q=-32710 cal/mol, t=388., 5°C (III) log p=12., 36-6636/T, Q=-30350 cal/mol, t=426., 9°C (IV) log p=10., 50-5500/T, Q=-25160 cal/mol, t=448., 7°C In these equations, it will probably be said that (I) corresponds to the dissociation of PbCO3, (II) to that of 2PbO·PbCO3, (III) to that of 11PbO·PbCO3, and (IV) to that of 19PbO·PbCO3., The same experiments were taken with artificial lead carbonate., The process of dissociation is shdwn as : PbCO3→PbO·PbCO3→17PbO·PbCO3→PbO in the air, and shown as : PbCO3→PbO·PbCO3(or PbO·3PbCO3)→PbO·PbCO3→2PbO·PbCO3→PbO in the CO2 gas., In cnclusion, the following two facts are remarkable., (1) With the intermediate basic salts, there are remarkable differences in the chemical composition and existing temperatures between the natural and artificial lead carbonate., (2) Even in the case of the same specimen, the intermediate basic salts differ somewhat in their chemical composition and their existing temperature according to the atmnospheric conditions whether the dissociation is taken in the air or in CO2 gas.,

Observations on Dysentery, and on the use of Astrigents, particularly the Cerussa Acetata and Opium in the cure of that complaint

Observations on Dysentery, and on the use of Astrigents, particularly the Cerussa Acetata and Opium in the cure of that complaint