New light on plant ash glass found in Africa: Evidence for Indian Ocean Silk Road trade using major, minor, trace element and lead isotope analysis of glass from the 15th-16th century AD from Malindi and Mambrui, Kenya.

Seventeen glass vessels and twenty glass beads recovered from the excavations at the ancient city of Malindi and the archaeological site of Mambrui in Kenya, east Africa were analysed using electron probe microanalysis (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results show that all of the glass samples are soda-lime-silica glass. They belong to the high alumina -plant ash glass type, characterised by high alumina and relatively low calcium contents, widely distributed in eastern (10th- 16th centuries AD) and southern Africa (13th - 15th centuries AD), Central Asia (9th- 14th centuries AD) and southeast Asia (12th- 13th centuries AD), made with plant ashes and sands. This is an understudied glass type for which previous research has indicated there were three types. When compared with published research on such glasses using Zr, Ti, Ba, Cr, La, Li, Cs, Na2O, MgO and CaO we have identified at least four different compositional groups of v-Na-Al glass: Types A, B, C and D. By comparing the results with contemporary v-Na-Al glass vessels and beads from Central Asia, Africa, and southeast Asia we show that most of the Malindi and Mambrui glass share similar characteristics to the compositions of Mapungubwe Oblate and some of the Madagascar glass beads from southern Africa. They belong to Type A v-Na-Al glass which is characterised by an elevated level of Ti and Ba and a relatively high ratios of Cr/La, relatively low Zr concentrations and low ratios of Zr/Ti. Differences in Zr, Li, MgO and Na2O concentrations in Type A glass indicates that there are subgroups which might derive from different glass workshop(s) specialising in Type A v-Na-Al glass production. Comparison with the chemical compositions of glass from Ghazni, Afghanistan and Termez, Uzbekistan, and by using lead isotope analysis, we suggest v-Na-Al glass was manufactured in Central Asia and possibly worked into vessels and beads there.

Historical accumulation of potentially toxic trace elements resulting from mining activities in estuarine salt marshes sediments of the Asturias coastline (northern Spain).

The extensive extraction activity of mercury ores in Asturias (northwest Spain), also rich in As and Sb, has impacted the Nalón river estuary. The objective of this research was to assess the historical evolution of As-Hg-Sb accumulation in the salt marsh sediments of this area. For this purpose, sediment cores were collected from two different salt marshes (eastern and western river banks) in the estuarine environment to evaluate the degree of anthropogenic enrichment and the geochronology of As-Hg-Sb accumulation. Core subsampling was performed by cutting 2-cm-thick slices of sediments. The subsamples were then analysed for several physical and chemical parameters. Sedimentation rate was assessed by measuring short-lived radionuclides (excess 210Pb and 137Cs). Pre-mining levels of As-Hg-Sb were observed at core depths below 50 cm. In the less extended salt marsh (eastern river bank), maximum As-Hg-Sb concentrations of 87.48, 3.66, and 5.75 µg·g-1, respectively, were found at the core top as a consequence of long-term mining activity in the area. The vertical distribution of As-Hg-Sb was influenced by the single-point contamination sources, whereas grain-size variability and diagenetic remobilisation did not seem affected. Geochronological measurements showed that the depositional fluxes of As-Hg-Sb were influenced by anthropogenic input after 1900, when mining activity in the area was most intense. Hg mining ceased in 1969; however, the corresponding core profiles did not show a drastic decreasing trend in element fluxes, implying that the river drainage basin retains some "memory" of contamination which affects riverine sediments. A preliminary gross estimation of total As-Hg-Sb "trapped" in the Nalón river salt marsh sediments amounted to approximately 18.7, 1.0, and 0.7 t, respectively. These morphological structures suffer erosive processes, thus representing a potential source of these elements associated with sediments; consequently, management conservation and monitoring of salt marshes should be taken into consideration from this environmental point of view.

Investigating the Essentiality and Requirements of Iron from the Ancient to the Present.

This review discusses the development of studies that evaluated the essentiality and requirements of iron from the ancient to the present. The therapeutic effects of iron compounds were recognized by the ancient Greeks and Romans. The earliest recognition of the essentiality of iron was stated by Paracelsus, a distinguished physician alchemist, in the sixteenth century. Iron was included in the earliest nutritional standard prepared for the Royal Army by E. A. Parkes, the first professor of hygiene. The League of Nations Health Organisation determined average iron requirements based on literature review. In the first US Recommended Dietary Allowances (RDA), the RDA of iron was determined from the results of iron balance studies. In the current Dietary Reference Intakes, iron requirements were determined based on the factorial method with the aid of Monte Carlo simulation for combining basal and menstrual iron losses. Population data analysis is a recently developed alternative that does not use the pre-estimated iron absorption rate and requires the prevalence of inadequacy instead. Population data analysis uses the convolution integral for combining basal and menstrual iron losses to ensure the required accuracy. This review also provides new estimates of hair and nail iron losses.

Historical aspects of iodine deficiency control.

In 1895, iodine was characterized as an essential element of thyroid tissue by Baumann. The efficacy of iodine to prevent goiter was demonstrated by Marine in Northern USA in 1916-1920. Severe endemic goiter and cretinism had been almost entirely eliminated from continental Western Europe and Northern America before the 1930's; however large populations elsewhere and even some places in Western Europe (Sicily) were still affected up to the 2000's. Public health consequences of iodine deficiency are not limited to endemic goiter and cretinism. Iodine deficiency disorders include also increased neonatal death rate and decreased intellectual development, although these consequences are not included in the current estimation of the Global Burden Disease related to iodine deficiency. Severe iodine deficiency as a public health problem is now largely under control worldwide, but can still affect isolated places, in hard-to-reach and/or politically neglected populations. We emphasize the importance of maintaining international cooperation efforts, in order to monitor iodine status where iodine deficiency is now adequately controlled, and identify at-risk population where it is not. The goal should be now global eradication of severe iodine deficiency. Commercial distribution of iodized salt remains the most appropriate strategy. A randomized clinical trial in New Guinea clearly showed in the 1970's that correcting severe iodine deficiency early in pregnancy prevents endemic neurological cretinism. This supports the essential role of thyroid hormones of maternal origin on the normal fetal development, during the first trimester of pregnancy (i.e. when fetal thyroid is still not functional). A randomized clinical trial in Congo (RD) in the 1970's also showed that correcting severe iodine deficiency during pregnancy prevents myxœdematous cretinism, particularly prevalent in affected Congolese areas.

Trace element research-historical and future aspects.

During the last 30 years the International Society for Trace Element Research and the Nordic Trace Element Society has been active . During this period the importance of these elements for human diseases has been increasingly recognized, including their contribution to the global burden of disease. New analytical methods allow biomonitoring data to be related to health outcome. Future research using modern chemical methods will focus more on elemental speciation and on measuring lower concentrations leading to further identifying adverse effects and critical organs. Extensive knowledge about essentiality and toxicity of trace elements in humans has emerged during the last two decades and at present the difficulties in defining a range of acceptable oral intakes for essential elements has largely been overcome. Biological monitoring of trace element concentrations in various media such as blood or urine is of great importance and an overview is given. As an example, a more detailed description of biological monitoring of cadmium is given, explaining biokinetics including the role of metallothionein in modifying kinetics and toxicity. Finally future challenges related to risk assessment of newly developed metallic nanomaterials and metal containing medical devices are discussed.

Historical trends of anthropogenic metals in Eastern Tibetan Plateau as reconstructed from alpine lake sediments over the last century.

Reconstructing trace metal historical trends are essential for better understanding anthropogenic impact on remote alpine ecosystems. We present results from an alpine lake sediment from the Eastern Tibetan Plateau to decipher the accumulation history of cadmium (Cd), lead (Pb) and zinc (Zn) over last century, from the preindustrial to the modern period. Cd, Pb and Zn in the sediment of Caohaizi Lake clearly suffered from atmospheric deposition, and the mining and smelting were regarded as the main anthropogenic sources. Since the mid-1990s, over 80% of trace metals were quantified from anthropogenic emissions. The temporal trends of anthropogenic metal fluxes showed that the contamination history of Pb was earlier than that of Cd and Zn, which was in agreement with the regional Pb emission history, but lagged behind the Pb decline in Europe and North America. The fluxes of anthropogenic Cd and Zn were relatively constant until the 1980s, increased sharply between the 1980s and the mid-1990s, and then kept the high values. The anthropogenic fluxes of Pb showed a marked rise around 1950, and increased sharply in the 1980s. In the mid-1990s, this flux reached the peak, and then decreased gradually. The Pb deposition flux at present in comparison with other lake records in the areas of Tibetan Plateau further demonstrated that trace metals in the Caohaizi Lake region were probably from Southwest China and South Asia. Economic development in these regions still puts pressure on the remote alpine ecosystems, and thus the impact of trace metals merits more attention.

A historical review of progress in the assessment of dietary zinc intake as an indicator of population zinc status.

Dietary components influencing zinc (Zn) bioavailability were implicated in the first cases of human Zn deficiency in the Middle East in the 1960s. It was not until the 1980s that isotope tracer studies in humans quantified the effects of the type and/or quantity of Zn, protein, iron, and phytate (myo-inositol hexaphosphate) on Zn absorption in humans and confirmed the dose-dependent inhibitory effect of phytate on Zn absorption. This led to further analysis of the Zn and phytate content of foods. The use of phytate-to-Zn molar ratios as likely estimates of absorbable dietary Zn followed together with an assessment of their relationship with Zn biomarkers in low-income countries (LIC). In the 1990s, increasing knowledge of factors governing Zn-absorption diets led to refinements of Zn requirements and algorithms to estimate dietary Zn bioavailability. Their use highlighted that inadequate Zn intake from plant-based diets were a major etiological factor in morbidity and stunting in LIC, prompting the need to identify indicators of the population's Zn status. Major advances in analyses of dietary data pioneered by Beaton in 1980s led to the endorsement in 2007 of a dietary Zn indicator based on the prevalence of the population with usual Zn intake below the estimated average requirement for Zn. Risk of Zn deficiency is a public health concern when the prevalence of inadequate Zn intake is >25%. Recent findings that Zn bioavailability from high-phytate, whole-day diets is lower than previous estimates suggest that revision of Zn estimated average requirement for LIC may be warranted.

History of zinc in agriculture.

Zinc was established as essential for green plants in 1926 and for mammals in 1934. However, >20 y would pass before the first descriptions of zinc deficiencies in farm animals appeared. In 1955, it was reported that zinc supplementation would cure parakeratosis in swine. In 1958, it was reported that zinc deficiency induced poor growth, leg abnormalities, poor feathering, and parakeratosis in chicks. In the 1960s, zinc supplementation was found to alleviate parakeratosis in grazing cattle and sheep. Within 35 y, it was established that nearly one half of the soils in the world may be zinc deficient, causing decreased plant zinc content and production that can be prevented by zinc fertilization. In many of these areas, zinc deficiency is prevented in grazing livestock by zinc fertilization of pastures or by providing salt licks. For livestock under more defined conditions, such as poultry, swine, and dairy and finishing cattle, feeds are easily supplemented with zinc salts to prevent deficiency. Today, the causes and consequences of zinc deficiency and methods and effects of overcoming the deficiency are well established for agriculture. The history of zinc in agriculture is an outstanding demonstration of the translation of research into practical application.

Severe and contrasted polymetallic contamination patterns (1900-2009) in the Loire River sediments (France).

The Loire River basin (117,800 km(2), France) has been exposed to multiple sources of metals during the last 150 years, originating from major mining districts (coal and non-ferrous metals) and their associated industrial activities. Geochemical archives are established here from the analysis of a 4m sediment core in the downstream floodplain and then compared to stream bed sediments from pristine monolithological sub-basins and from bed and bank sediments in impacted tributaries. The contamination is assessed for 55 major and trace elements through their enrichment factors to Al (EF), normalized to the pre-anthropogenic background. Archives from 1900 to 2009 show enrichment (EF<1.3) not only for Ba, Be, Cs, Ga, Rb, REE, Sr, V, and Zr but also for U and Th, despite U mining activities until the 1990s. From 1900 to 1950, the level of contamination is severe for Hg, Au, Ag (10

BioMetals: a historical and personal perspective.

Understanding of BioMetals developed basically from a starting point about 60 years ago to current mechanistic understanding of the biological behavior of many metal ions from protein structural and functional studies. Figure 1 shows a Biochemical Periodic Table, element by element, with requirements, roles and biochemistry of the specific ions indicated. With few exceptions, the biology is of the ions formed and not of the elemental state of each. Early BioMetals efforts defined nutritional growth needs for animals, plants and microbes for inorganic "macro-nutrients" such as magnesium, calcium, potassium, sodium, and phosphate and of "micronutrients" such as copper, iron, manganese and zinc. Surprises came early with regard to microbes, for example the finding that Escherichia coli (then and now the standard microbial model) grows happily in the apparent total absence of calcium, sodium, and chloride, which are certainly major animal nutrients. Some elements such as mercury and arsenic are never required by living cells, but are always toxic, often at very low levels. Therefore, the division into nutrient elements and toxic elements came soon. For most inorganic nutrients, excessive amounts can be toxic as well, for example for copper and iron.

Zinc in cancer prevention.

Essentiality of zinc for humans was discovered 45 yr ago. Deficiency of zinc is prevalent world wide in developing countries and may affect nearly 2 billion subjects. The major manifestations of zinc deficiency include growth retardation, hypogonadism in males, cell-mediated immune dysfunctions, and cognitive impairment. Zinc not only improves cell mediated immune functions but also functions as an antioxidant and anti-inflammatory agent. Oxidative stress and chronic inflammation have been implicated in development of many cancers. In patients with head and neck cancer, we have shown that nearly 65% of these patients were zinc deficient based on their cellular zinc concentrations. Natural killer (NK) cell activity and IL-2 generation were also affected adversely. Th2 cytokines were not affected. In our patients, zinc status was a better indicator of tumor burden and stage of disease in comparison to the overall nutritional status. Zinc status also correlated with number of hospital admissions and incidences of infections. NF-kappa B is constitutively activated in many cancer cells, and this results in activation of antiapoptotic genes, VEGF, cyclin DI, EGFR, MMP-9 and inflammatory cytokines. Zinc inhibits NF-kappa B via induction of A-20. Thus, zinc supplementation should have beneficial effects on cancer by decreasing angiogenesis and induction of inflammatory cytokines while increasing apoptosis in cancer cells. Based on the above, we recommend further studies and propose that zinc should be utilized in the management and chemoprevention of cancer.

Elements in the history of the Periodic Table.

Discovery of the Periodic Table was rendered possible only after four decisive prerequisites had been achieved. These were (i) the abandonment of the metaphysical and occult notions of elements that typified the alchemical era; (ii) the adoption of a modern and workable definition of an element; (iii) the development of analytical chemical techniques for the isolation of the elements and determination of their properties; and (iv) the devising of a means of associating each element with a characteristic natural number. The Periodic Table made its appearance on cue almost as soon as these preconditions had been fulfilled.

The loading history of trace metals and nutrients in Altata-Ensenada del Pabellón, lagoon complex, northwestern Mexico.

This paper summarizes the geochemical investigations about the origin and loading history of some trace metals (Ag, Cu and Zn) and nutrients (N and P) in the coastal lagoon complex of Altata-Ensenada del Pabellón, Mexico, by using the radioactive chronometers 210Pb and 228Th and the stable isotopes of C and N. The examination of sediment cores collected at different locations in the lagoon system identified a slight enrichment in metals and nutrients in some points, which was mainly associated to organic matter accumulation. Stable C and N isotope ratios revealed wastewater inputs to the lagoon system and the 210Pb geochronology showed that anthropogenic impact started 50 years ago, with the beginning of the agriculture development and the associated urban growth of the surrounding area. Several atypical 210Pb and 228Th/232Th profiles demonstrated that biological and physical disturbances are common phenomena in these environments, that frequently mask the pollution records; and therefore, considering that the contaminated sediments at some locations in the lagoon system are frequently resuspended and re-oxygenated, the pollutants will continue to be easily remobilized in the food chain.

Dialysis.

Willem Kolff designed his "kunstmatige nier" in the early 1940s using spare parts obtained from the Wehrmacht; with it, he treated 14 patients with acute renal failure. Although there has been a tremendous improvement in the design and construction of dialysis machines, the basic concepts are unchanged. In this review we show that dialysis dose and adequacy can now be predicted using simple clinical methodology. The second part of the article discusses the accumulation or excess removal of important biologically active substances which can result in hitherto unseen clinical syndromes and even pose a threat to life.

Trace metals in ancient hair from the Karluk Archaeological Site, Kodiak, Alaska.

Considerable interest exists in characterizing the extent of changes in methylmercury exposures from preindustrial to modern-day times. Hair is often preserved over centuries and has been useful in determining the extent of dietary trace metal exposures, particularly methylmercury. We examined 16 human hair samples taken from human hair bundles buried in the soil of the Karluk One Archaeological site located near the current Karluk village on the Kodiak Archipelago of Alaska. Hair samples were analyzed for total mercury, methylmercury, selenium, and cadmium. The mean total mercury level was 1.33 ppm (SD = 1.09). The mean methylmercury level, however, was considerably lower than the total mercury concentration: the mean methylmercury level was 0.03 ppm (SD = 0.02). The mean cadmium level was 0.15 ppm (SD = 0.14) and the mean selenium level was 5.22 ppm (SD = 5.73). While the concentration of total mercury in the Karluk hair samples is comparable to those observed in ancient hair from other locations, direct methylmercury quantization demonstrated that methylmercury levels were less than 2% of the total mercury in these hair samples. Because the hair was subjected to a variety of environmental influences over the centuries, the possibility of degradation of methylmercury in the hair over the last 400 to 800 years cannot be ruled out. The use of hair from remains found in more protected frozen or dry environments may provide the best evidence for the extent of preindustrial exposures to methylmercury and other trace metals.