Specific Trace Metals Research Articles

Assessment of Serum Zn, Cu, Mn, and Fe Concentration in Women with Endometrial Cancer and Different Endometrial Pathologies.

There is conflicting evidence on the effect of specific micronutrient concentration and cancer risk. In this study, we investigated the differences in serum zinc, copper, iron, and manganese levels and different endometrial pathologies, including endometrial cancer. 110 patients with a confirmed diagnosis of endometrial cancer, benign uterine conditions (endometrial polyp, endometrial hyperplasia, uterine myoma), or normal endometrium were included in the study and assessed in terms of endometrial cancer risk factors. The measurements of serum micronutrients were conducted using inductively coupled plasma optical emission spectrometry. When assessing for differences between serum concentrations of trace metals, we found significant differences in the distribution of Mn (p < 0.001) and Fe (0.034). There was also a significant difference in Cu/Zn ratio between the analyzed groups (p = 0.002). Patients' BMI was found to influence Cu concentration, with obese patients having higher mean copper concentration (p = 0.006). Also, patients' menopausal status was shown to influence Cu concentration with postmenopausal patients having higher Cu levels (p = 0.001). The menopausal status was found to influence Cu/Zn ratio (p = 0.002). Univariable regression analysis did not confirm that any of the micronutrients significantly influence the risk of endometrial cancer. The concentration of specific trace metals varies between different histopathological diagnoses of endometrial pathologies. Menopausal status and patient BMI are endometrial cancer risk factors impacted by the concentrations of Cu and Zn and their ratio.

Year-long monitoring of phytoplankton community, toxigenic cyanobacteria, and total microcystins in a eutrophic tropical dam supplying the Mexico megacity

The Valle de Bravo dam is an important source of drinking water supply for the Mexico City Conurbation (&amp;gt;26 million inhabitants) and is also a hotspot for nautical sports, recreational fishing, and tourism. However, anthropogenic pressures in the upper reaches of the basin have led to increased eutrophication and numerous harmful cyanobacterial blooms (HCBs). To determine the effect of abiotic variables on the characteristics of the phytoplanktonic community, as well as their influence on the diversity of toxigenic cyanobacteria and related cyanotoxins, we evaluated monthly variations in environmental factors, phytoplankton biovolume and composition and total microcystins in Valle de Bravo dam during the year of 2019. Overall, 75 phytoplanktonic species were identified, mostly belonging to the divisions Cyanobacteria, Chlorophyta, and Bacillariophyta. Cyanobacteria presented the highest biomass throughout the year, with water temperature and rainfall being the best correlated factors. The highest concentrations of total microcystins were recorded from July to September (maximum of 71 μg L−1), associated with the dominance of species such as M. smithii, M. aeruginosa, M. viridis M. flos-aquae, Aphanocapsa planctonica, and Dolichospermum crassum, and environmental factors such as rainfall, total dissolved solids, water temperature, and specific trace metals. In all months except December, the total cyanobacterial biovolume was above the World Health Organization alert level two, indicating potentially high risks to human health. The predominance of cyanobacteria and high biovolumes classified water quality as poor to very poor during most of the year. To avoid the development of HCBs in this dam, the contribution of nutrients by the tributary rivers and sewage must be controlled, since the poor-quality conditions of the water threaten the aquatic biota, the sports and recreation activities and affect the potable water supply.

Trace Element Export From the Critical Zone Triggered by Snowmelt Runoff in a Montane Watershed, Provo River, Utah, USA

The Critical Zone is an important source of trace elements to headwater streams during the snowmelt runoff period, yet the mechanisms of trace element release are poorly characterized. To evaluate changes in water chemistry in response to snowmelt, we measured trace element and major ion concentrations at three sites in the upper Provo River in northern Utah, USA, over a five–year period spanning years with below– and above–average discharge. We also sampled snowpack, ephemeral streams, and soil water to investigate trace element sources. The river drains siliciclastic bedrock above the upper site, carbonate rocks between the upper and middle sites, and volcanic rocks between the middle and lower sites, with minimal anthropogenic impacts in the watershed. Concentrations of specific trace metals (Be, Al, Cu, and Pb) and rare earth elements (represented by La and Y) increased during snowmelt runoff each year at all three sites, with decreasing concentrations from upstream to downstream. In contrast, major ion concentrations, including Ca2+ and SO42-, were similar year–round at the upper site and were diluted during snowmelt at the lower sites, with increasing concentrations from upstream to downstream. The snowmelt runoff period (April–June) accounted for >84% of the annual trace element loading, with most trace element inputs occurring above the upper sampling site. Concentration–discharge (C–Q) relationships revealed variations in solute behavior from upstream to downstream. For example, at the upstream site the trace elements had a slight positive slope in log C–log Q space, while Ca2+ and SO42- had zero slope. At the downstream sites, the trace elements had a strong positive slope and Ca2+ and SO42- had a negative slope. Trace element concentrations were relatively low in snowpack but elevated in ephemeral streams and soil water, suggesting that flushing of shallow soils by snowmelt causes increased trace element concentrations with positive C–Q relationships in the upper part of the river. Trace element loads propagate downstream where concentrations are diluted by groundwater inputs from carbonate bedrock. Our results demonstrate that soil water flushing in the Critical Zone at the headwaters of mountain streams is an important control on downstream water chemistry.

The content and distribution of trace elements and polycyclic aromatic hydrocarbons in soils of Maritime Antarctica.

Antarctica is considered as one of the most pristine areas on Earth. However, increasing intensity of human presence on the sixth continent (scientific operations, functioning of the numerous scientific stations, tourism activities) makes it crucial to investigate the level of environmental pollution within the vulnerable ecosystem of Antarctica. Soils play a significant role in processes of accumulation, mobilization, redistribution of chemical elements within landscapes, and ecosystems. The aim of this work was to analyze the levels of 17 polycyclic aromatic hydrocarbons and eight trace elements in soils of King George and Ardley islands, Western Antarctica. Moreover, our work was aimed to determine the trends and reasons of anthropogenic pollution of Antarctic soils and characterization of accumulation levels of trace elements and PAHs. Results showed the predominance of light PAHs in all studied sites. The content of benzo(a)pyrene does not exceed the threshold concentration (adopted by different national environmental legislation systems). At the same time, the content of benzo(a)pyrene, which is a marker of anthropogenic contamination, is relatively low or equal to 0 in soils of reference landscapes. Cu and Zn were found as most abundant elements in all studied soils. The highest lead concentration content has been described in soil from Bellingshausen station. In general term, obtained Igeo values for trace elements in all samples were under or slightly above the 0 level, indicating low to moderate pollution of the studied soils. This study also contributes new data on trace element accumulation in soils strongly influenced by ornithogenic factor. Principal component analysis allowed to estimate the probable sources of specific trace metals and their relationship with soil variables. Ornithogenic factor has been also revealed as a driver for some trace element accumulation especially in breeding penguin colonies. High contents of organic matter in ornithogenic habitats could increase trace metal mobility, environmental risks for surrounding terrestrial environments should be considered.

Impact of ice-free oases on particulate matter over the East Antarctic: Inferences from the carbonaceous, water-soluble species and trace metals

The present study reports on carbonaceous, water-soluble species and trace metals in PM10 aerosols collected at Bharati station during the austral summer (December 17, 2016 to February 2, 2017) over East Antarctica. Organic matter was the predominant among all measured species followed by nss-Ca2+ and nss-SO42-. Two distinct air masses that arrive from high-altitude-troposphere (HTAs) and low-altitude-troposphere (LTAs) regions which clearly showed significant differences in concentrations of measured chemical and metal species as inferred from the air mass backward trajectory analysis and mixed layer height variations. Based on significant positive correlations among chemical species, aerosol liquid water content (ALWC), and PM10 mass, we confirmed that the aqueous-phase formation of secondary aerosols followed by atmospheric processing are possible sources in HTAs while primary emissions associated with soil/dust from ice-free regions and in-situ emissions are major sources in LTAs. This result further supported by significant (p < 0.05) higher concentrations of specific trace metals (for example, Fe, Ti, and Pb) in LTAs. Moreover, higher cation-to-anion (Σ+/Σ−) ratios suggesting the alkaline nature of aerosols at Bharati. The present study demonstrates that ice-free regions over East Antarctica may act as major sources of particulate matter, thus significant implications toward climate change over the global environment.

Selective anaerobic fermentation of syngas into either C2-C6 organic acids or ethanol and higher alcohols

Clostridium carboxidivorans produces alcohols from C1 gases (CO, CO2), converting them first into fatty acids, and subsequently into alcohols. This research identified conditions that allow to selectively produce either fatty acids or alcohols. The conversion of gases into acids and then into alcohols is catalysed by metalloenzymes, stimulated by specific trace metals. Therefore, different bioreactors were set-up, either with or without addition of tungsten (W) or selenium (Se) and at different pHs. Combining the presence of those trace metals with a low pH (5.0) allowed to accumulate high amounts of alcohols as major end products (8038 mg/L total alcohols; 3027 mg/L total acids). Instead, maintaining a higher pH (6.2), in the absence of those trace metals, allowed to selectively produce organic acids (9577 mg/L) and almost no alcohols (676 mg/L). Omitting W, but not Se, at high pH (6.2), led to a still higher concentration of acids (11303 mg/L).

Water Quality, Sediment Characteristics and Benthic Status of the Razim-Sinoie Lagoon System, Romania

AbstractRazim Lake is the biggest of Romania’s freshwater lakes and along with other basins as Golovita, Zmeica and Sinoie constitutes a system of great ecological significance, playing also an essential role in the supply of water for irrigation, fishery exploitation, farming, flood prevention, recreational navigation and water tourism. Due to their importance, the environmental conditions in the Razim - Sinoie coastal lakes have attracted an increased public attention in contemporary society. To assess the levels, dissemination and potential sources of contamination in the above-mentioned lagoon system, random sampling was used to collect water and sediment samples from every lake and several analytical techniques were performed to investigate their environmental characteristics. The results obtained from this study indicated that, in water, concentrations of various physico-chemical parameters are, mostly, in agreement with correlated environmental standards. Slight variations and/or occasional exceeding of the maximum admissible limits were generally limited to small areas showing levels that would not warrant special concern. In sediments, the mean concentrations of some specific trace metals were below the levels of potential effect. Benthic samples revealed 31 taxa belonging to 16 zoo-benthal subdivisions. The results of this study showed good ecological status despite local several natural and anthropogenic stressors as fishery exploitation, farming, recreational navigation and water tourism.

Effects of Trace Metal Concentrations on the Growth of the Coral Endosymbiont Symbiodinium kawagutii.

Symbiodinium is an indispensable endosymbiont in corals and the most important primary producer in coral reef ecosystems. During the past decades, coral bleaching attributed to the disruption of the symbiosis has frequently occurred resulting in reduction of coral reef coverage globally. Growth and proliferation of corals require some specific trace metals that are essential components of pertinent biochemical processes, such as in photosynthetic systems and electron transport chains. In addition, trace metals are vital in the survival of corals against oxidative stress because these metals serve as enzymatic cofactors in antioxidative defense mechanisms. The basic knowledge about trace metal requirements of Symbiodinium is lacking. Here we show that the requirement of Symbiodinium kawagutii for antioxidant-associated trace metals exhibits the following order: Fe >> Cu/Zn/Mn >> Ni. In growth media with Cu, Zn, Mn, and varying Fe concentrations, we observed that Cu, Zn, and Mn cellular quotas were inversely related to Fe concentrations. In the absence of Cu, Zn, and Mn, growth rates increased with increasing inorganic Fe concentrations up to 1250 pM, indicating the relatively high Fe requirement for Symbiodinium growth and potential functional complementarity of these metals. These results demonstrate the relative importance of trace metals to sustain Symbiodinium growth and a potential metal inter replacement strategy in Symbiodinium to ensure survival of coral reefs in an oligotrophic and stressful environment.

Sex-associated differences in trace metals concentrations in and on the plumage of a common urban bird species.

Urban areas encompass both favorable and stressful conditions linked with human activities and pollution. Pollutants remain of major ecological importance for synanthropic organisms living in the city. Plumage of urban birds harbour trace metals, which can result from external deposition or from internal accumulation. External and internal plumage concentrations likely differ between specific trace metals, and may further differ between males and females because of potential sex-linked differential urban use, physiology or behaviour. Here, we measured the concentrations in four trace metals (cadmium, copper, lead and zinc) in both unwashed and washed feathers of 49 male and 38 female feral pigeons (Columba livia) from Parisian agglomeration. We found that these concentrations indeed differed between unwashed and washed feathers, between males and females, and for some metals depended on the interaction between these factors. We discuss these results in the light of physiological and behavioural differences between males and females and of spatial repartition of the four trace metals in the city.

Ash behaviour and emission formation in a small-scale reciprocating-grate combustion reactor operated with wood chips, reed canary grass and barley straw

The emissions and ash behaviour during combustion of wood chips, or co-combustion of two solid agricultural fuels (reed canary grass and barley straw) with wood chips, were studied. In addition, the sensitivity of the results towards different air-staging conditions was investigated using pure wood chips. The experiments were carried out in a 40-kW combustion reactor equipped with a reciprocating-grate burner. The addition of the reed canary grass to the wood chips increased only slightly the emission of fine particles (PM1), nitrogen oxides (NOX) and sulphur dioxide (SO2); while carbon monoxide (CO), hydrogen chloride (HCl), organic carbon (OC), elemental carbon (EC) and the geometric diameter (GMD) of the particles either decreased or remained unchanged. However, the number of particles emitted increased 2-fold in the reed canary grass combustion compared to the pure wood chips. In contrast, the addition of straw to wood chips substantially increased the emissions of PM1, CO, EC, SO2 and HCl. The straw-originating particles were mostly crystalline KCl, and their number emission was clearly reduced, but their size was larger compared to the case with pure wood chips. The distribution of the combustion air had only a very minor influence on the release of the major ash species, whereas the effect was significant for the release of specific trace metals and the products of incomplete combustion. Finally, the partitioning of ash-forming elements with various fuels was evaluated based on chemical analyses of the fuel, bottom ash and fine fly ash fractions.

Effect of Divalent Metals on Hg(II) Uptake and Methylation by Bacteria

The production of methylmercury by some bacteria is a key first step in the accumulation and biomagnification of this toxic substance in aquatic food webs, a major human health concern. By direct measurement of cellular Hg(II) uptake in model iron and sulfate reducing bacteria, we have observed that specific trace metals, such as Zn(II) and Cd(II), inhibit uptake and methylation in these organisms, whereas other metals, such as Ni(II), Co(II), or Fe(II), do not. The inhibition of Hg(II) methylation by Zn(II) was competitive in nature and related to the concentration of inorganically complexed Zn(II) (Zn'). The inhibition of Hg(II) methylation was alleviated by decreasing the free Zn' concentration through complexation with nitrilotriacetic acid without altering the speciation of Hg(II). The inhibitory effect by Zn(II) was observed when either Hg-cysteine complexes or neutral HgCl2 dominated the speciation of Hg(II), demonstrating that both charged and neutral species are transported into the cytosol by an active rather than passive process. We propose that Hg(II) uptake is the result of its accidental uptake by metal transporter(s), possibly one effecting the transport of Zn(II).

Rigid versus Flexible Ligands on Carbon Nanotubes for the Enhanced Sensitivity of Cobalt Ions

Carbon nanotubes have shown great promise in the fabrication of ultracompact and highly sensitive chemical and biological sensors. Additional chemical functionalization schemes can controllably improve selectivity of the carbon nanotube-based sensors; however, the exact transduction mechanism is still under debate. In this article we detail the synthesis and selective response of single-walled carbon nanotubes (SWNTs) functionalized with polyazomethine (PAM) polymer toward the application of a specific trace metal ion detector. The response of the polymer system was compared to shape persistent macrocycle (MAC) comprised of identical ion coordination ligands. While ion detection with rigid MAC/SWNT chemiresistor was comparable to bare SWNT, flexible PAM offers significant SWNT signal amplification, allowing for picomolar detection of Co2+ ions with both selectivity and a fast response. We hypothesized that rearrangement of the flexible PAM on the SWNT network is a sensing mechanism which allows for ultrasensitive detection of metal ions. The electron transfer and polymer rearrangement on the SWNT were studied by a combination of optical spectroscopy and electrical measurements—ultimately allowing for a better understanding of fundamental mechanisms that prompt device response.

Trace metal contents in male, non-ovigerous and ovigerous females, and the egg sacs of the marine copepod, Euchaeta concinna Dana, 1849 (Copepoda, Euchaetidae), collected from the southern East China Sea

Marine copepods have a great ability to accumulate trace metals from seawater. The trace metal content in marine copepods may vary both intra- and inter-specifically. However, the known specific trace metal content of the copepod sexes and according to the ovigerous status of the females is very limited. Copepod samples of Euchaeta concinna Dana, 1849, were collected from the southern East China Sea and separated into four groups: males; non-ovigerous females; ovigerous females without egg sacs, and egg sacs, in order to analyse the trace metal contents (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in these samples. These trace metal contents were found to range between 0.04 and 195.7 μg/g. Zinc, Fe, and Cu were the major components among the trace metals studied and their concentrations generally exceeded 10 μg/g. The trace metal contents in the copepod body generally exceeded the amount in the egg sacs. However, the Cr concentration in the egg sacs was much higher than that in the copepod body, either male or female, and the value ranked as second just behind Zn among the metals studied. The nickel content was also slightly higher in the egg sacs. This study provides the important finding that E. concinna egg sacs contained Cr concentrations out of all proportions to that of the copepod body. Yet, why E. concinna egg sacs contain relatively higher Cr concentrations than the body remains a question to be answered.

Trace metals distribution from a serpentinite weathering at the scales of the weathering profile and its related weathering microsystems and clay minerals

The distribution of four trace metals – nickel (Ni), chromium (Cr), manganese (Mn) and cobalt (Co) – and some major elements is studied in a soil profile derived from a natural trace metals-bearing rock (serpentinite), at the scales of (1) the weathering profile (C and B horizons) and (2) its related weathering microsystems and clay minerals. All trace elements are relatively enriched in weathered horizons compared to the rock, in the same way as iron and aluminium whereas magnesium is largely leaching. An evolutive sequence of trace metals host phases is formed along the weathering profile from magnesian at the bottom to iron rich clay minerals, and then aluminous clay minerals and oxy-hydroxides at the top. Different chemical forms of trace metals in weathering profile have been quantified by chemical extractions. Ni and Cr remain mainly in the silicates. In contrast, Mn and Co are mainly distributed into amorphous oxy-hydroxides. In addition, trace metals contents are measured (using electron microprobe) in individual rock-forming minerals and in their specific weathering microsystem each with its specific clay mineral. Each rock-forming mineral serves as the host phase for a specific trace metal. Silicates (serpentine and clinochlore) contain Cr, Ni and Mn whereas oxides concentrate Co and Cr. In the first weathering stages, Ni and Cr are concentrated in secondary clays, especially in Fe-montmorillonite (derived from mesh serpentine minerals) and in trioctahedral vermiculite (derived from chlorite) respectively, whereas Mn and Co are mainly used to constitute secondary oxides. At the top of the profile, Mn, Co and Ni host secondary oxy-hydroxides have developed due to iron segregation.

Steady state characteristics of acclimated hydrogenotrophic methanogens on inorganic substrate in continuous chemostat reactors

A Monod model has been used to describe the steady state characteristics of the acclimated mesophilic hydrogenotrophic methanogens in experimental chemostat reactors. The bacteria were fed with mineral salts and specific trace metals and a H 2/CO 2 supply was used as a single limited substrate. Under steady state conditions, the growth yield ( Y CH 4 ) reached 11.66 g cells per mmol of H 2/CO 2 consumed. The daily cells generation average was 5.67 × 10 11, 5.25 × 10 11, 4.2 × 10 11 and 2.1 × 10 11 cells/ l-culture for the dilutions 0.071/d, 0.083/d, 0.1/d and 0.125/d, respectively. The maximum specific growth rate ( μ max) and the Monod half-saturation coefficient ( K S) were 0.15/d and 0.82 g/L, respectively. Using these results, the reactor performance was simulated. During the steady state, the simulation predicts the dependence of the H 2/CO 2 concentration ( S) and the cell concentration ( X) on the dilution rate. The model fitted the experimental data well and was able to yield a maximum methanogenic activity of 0.24 L CH 4/g VSS.d. The dilution rate was estimated to be 0.1/d. At the dilution rate of 0.14/d, the exponential cells washout was achieved.

Trace Elements in Recent and Fossil Bone Apatite

The biomineral component of bones and teeth is synthesized within the body, under direct physiological control, and therefore the chemistry of bone (including the trace element chemistry) reflects aspects of the animal’s biology, particularly the trace metal load, but also the state of metabolism of specific trace metals. Bone mineral is relatively reactive due principally to its small crystal size, and consequently bone is unstable once removed from the body. Bone undergoes a complex set of diagenetic processes post mortem, which generally lead to dissolution, however bones and teeth are relatively common components in (post-Ordovician) rocks. The trace element content of bone is susceptible to alteration immediately upon exposure, and while these changes reduce the usefulness of ancient bone as a monitor of the physiology or diet of ancient animals the trace element composition of ancient bone can yield useful paleoenvironmental information. This chapter is concerned principally with archaeological and geological applications of trace element chemistry of bone, rather than physiological or medical implications. The inorganic (mineral) component of bone is carbonated calcium phosphate (Ca10(CO3,PO4)6(OH)2), similar to the mineral dahllite. The calcium phosphates form the vast majority of all vertebrate hard tissues (Young and Brown 1982), and exhibit a very wide range of physical and chemical properties. Stoichiometric hydroxyapatite is not known biologically, and is only produced artificially or geologically at high temperature and pressure. The mineralogy of bone, dentine, and enamel is reviewed in Elliott (this volume). Kohn and Cerling (this volume) highlight the fact that apatite crystal size and shape varies between bone and enamel, and point out that variations in crystal size are in part responsible for the greater diagenetic susceptibility of bone compared to enamel. Bone crystallites are essentially plate-shaped, with average dimensions of 350–400 A × …

Electrochemical or photocatalytic reduction of carbon dioxide released to the environment, and atomic spectrometry for environmental sample analysis

CO2 causes the greenhouse effect and consequent natural disruption of the environment. Therefore, it needs to develop technologies for the sequestration and reduction of CO2. On the other hand, some diseases with the chronic intake of metals at low concentration will possibly become a problem in the future, which means that it is required to develop accurate analytical methods for metals at even lower concentration. Based on these circumstances, the electrochemical or photocatalytic reduction of CO2 released to the environment, and atomic spectrometry for environmental samples were investigated. First, in the electrochemical reduction of CO2 in methanol, the reduction products could be controlled by the selections of supporting electrolytes and cathode materials. Furthermore, the photocatalytic CO2 reduction reaction could proceed in liquid and supercritical CO2 media. Next, a sensitive and accurate analytical method of specific trace metals, such as cobalt, silver and rhodium, in environmental samples by electrothermal atomization atomic absorption spectrometry with a metal tube atomizer was developed. Moreover, a direct determination method of elemental content in individual dried biological cells and particulates by ICP-AES or ICP-MS was investigated. These determination methods may play a significant role in various fields, such as environmental science, pharmacy and biochemistry.

Environmental Geochemistry of Kimberlite Materials: Diavik Diamonds Project, Lac de Gras, Northwest Territories, Canada

Prior to the development of the Diavik Diamonds Project, baseline studies were conducted to determine the geochemical characteristics of four kimberlite orebodies as an aid in the design of both the water-management system and the facilities for containment of processed kimberlite and ore stockpiles. Materials tested included field samples of volcaniclastic and pyroclastic kimberlite, processed kimberlite (i.e., kimberlite ore which had been screened and washed as part of the processing procedure), and sedimentary mudstone (a minor xenolithic unit which was assimilated during kimberlite emplacement). Approximately 200 samples of kimberlite materials were collected as part of the geochemistry program. Test-work included whole-rock chemical analyses, acid-base accounting, kinetic leach tests using columns, and mineralogical analyses. Diavik kimberlite has major oxide and trace-element concentrations consistent with global averages for kimberlite. The mean total-sulfur content of the kimberlite material is 0.22 wt% S, but with a significant range. The kimberlite has an excess of carbonate minerals over sulfide minerals (average CO 2 = 4 wt%, present mainly as calcite), and has a mean neutralization potential of 311 kg CaCO 3 equivalent/tonne. A reactive form of framboidal pyrite associated specifically with the mudstone xenoliths is the primary source of sulfide-sulfur. Long-term kinetic tests confirmed the preliminary interpretations that were made from the static-test results. Kimberlite and processed kimberlite are net acid-consuming materials that produce alkaline drainages and have low but detectable leaching rates for SO 4 and specific trace metals such as Al, Co, Cu, Ni, and Zn. If segregated from the kimberlite, mudstone xenoliths are acid-generating (pH = 3) and produce an effluent with elevated concentrations of SO 4 , Fe, Al, Cu, Ni, and Zn. The study demonstrates that xenolithic units in Diavik kimberlites have an important effect on the environmental geochemistry of the ore rock. The mineralogy and aqueous geochemistry of the kimberlite materials are such that they may not be suitable for general earthworks or as an alkaline agent and should report to an engineered facility to protect site water quality.

Alterations in plasma copper, zinc, and ceruloplasmin levels in patients with thermal trauma.

This review was undertaken to elucidate the trends in copper, zinc, total serum protein, and ceruloplasmin levels in patients with thermal trauma. Medical records of pediatric and adult patients were retrospectively reviewed. The findings showed a significant linear decline in mean plasma copper, ceruloplasmin, and total serum protein during the first three days postburn, followed in general by a gradual rise in levels; however, patients with burns larger than 60% TBSA maintained copper, zinc, and ceruloplasmin levels significantly below the lower limits of normal during the observation period. Significant decrements in copper, zinc, total serum protein, and ceruloplasmin levels have been demonstrated in these patients. Trace metal determinations should be obtained in patients with significant burns soon after admission and routinely throughout their hospital course. Specific trace metal supplementation should be administered when indicated.

Accuracy of selective extraction procedures for metal speciation in model aquatic sediments

The interpretability of a selective extraction procedure for metals in aquatic sediments was tested by means of synthetic models. The major sedimentary geochemical phases were prepared and characterized by X-ray diffraction and scanning electron microscopy. A specific trace metal was doped into each phase by adsorption or coprecipitation, content being verified by atomic absorption (AA). The phases and metals were calcite (Pb), iron sulfides (zn), humic acid (Cu), and iron oxyhydroxides (Cu or Ni). Three different model sediments were prepared by combining phases and diluting with silica or illite. Measurements of extracts by AA and inductively coupled plasma (ICP) indicated that trace metals were not recovered in the appropriate fractions. This implies that selective extraction procedures as currently practiced may not be suitable for distinguishing the phase association of metals in real sediments.