Showing papers on "Trace metal published in 2006"

Trace metal concentrations and water solubility in size-fractionated atmospheric particles and influence of road traffic

Abstract: The abundance and the behavior of metals (Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Ba, Pt, Hg, and Pb) and ions (Na+ K+ Mg2+ Ca2+, NH4+, Cl-, NO3-, SO4(2-), PO4(3-), and oxalate) in size-fractionated atmospheric particulate matter (PM) were studied in the U. K. and Ireland at four observation sites simulating extreme degrees of vehicular-traffic influence in the environment. Trace metals in urban PM showed distinct types of size-fractionated behavior depending on the particle sources from which they originate. In coarse PM (1.5 < Dp < 3.0 microm) the concentrations of copper, barium, and iron correlated closely across over 2 orders of magnitude in urban air, which is seen as evidence that major portions of transition metals (Cu, Ba, Fe, and Mn) are released through abrasive vehicular emissions, particularly the wear of brake linings. Further results are strongly indicative of a decoupling of coarse iron and calcium, the former arising predominantly from vehicles, the latter from soil resuspension. In fine PM (Dp < 0.5 microm), several combustion and secondary sources of particulates were identified, but these were much less unique in terms of elemental fingerprints. An analysis of the water solubility of trace metals yielded that solubility varies considerably with element and, to a lesser extent, with particle size. Notable differences were found to the elemental water solubilities determined in previous work, partially explained by differences in extraction procedures.

Trace heavy metal contents of some spices and herbal plants from western Anatolia, Turkey

Abstract: Trace metal levels in eleven different spice and herbal plant species from western Anatolia, Turkey were determined by atomic absorption spectrometry. The contents of trace metals in the herbal plant samples were found in the ranges: 3.8-35.4 μg g -1 for copper, 0.2-2.7 μg g -1 for cadmium, 0.1-2.8 μg g -1 for lead, 1.4-11.3 μg g -1 for nickel, 0.1-9.7 μg g -1 for chromium, 30.0-945.3 μg g -1 for iron, 7.9-152.5 μg g -1 for manganese and 5.2-83.7 μg g -1 for zinc. Results obtained are in agreement with data reported in the literature.

Trace Metals in Anaerobic Granular Sludge Reactors: Bioavailability and Dosing Strategies

Abstract: The trace metal dynamics in anaerobic granular sludge bed reactors and their influence on reactor performance is reviewed in this paper. An insight into the metal dynamics is required from a practical point of view in order to be able to early recognize limitations for essential trace elements, viz., to know when dosing of these elements is required in full-scale anaerobic bioreactor applications. Further such knowledge is indispensable for a rational dosage of these metals, e.g., to ensure maximum substrate conversion rates and to prevent disturbances in reactor performance using a minimum amount of metals. Therefore, the retention, accumulation and release of trace metals in anaerobic granular sludge and the factors affecting these processes need to be known.

Geochemical cycling of arsenic in a coastal aquifer.

Abstract: Biogeochemically modified pore waters from subterranean estuaries, defined as the mixing zone between freshwater and saltwater in a coastal aquifer, are transported to coastal waters through submarine groundwater discharge (SGD). SGD has been shown to impact coastal and perhaps global trace metal budgets. The focus of this study was to investigate the biogeochemical processes that control arsenic cycling in subterranean estuaries. Total dissolved As, as well as a suite of other trace metals and nutrients, were measured in a series of wells and sediment cores at the head of Waquoit Bay, MA. Dissolved As ranged from below detection to 9.5 microg/kg, and was associated with plumes of dissolved Fe, Mn, and P in the groundwater. Sedimentary As, ranging from 360 to 7500 microg/kg, was highly correlated with sedimentary Fe, Mn, and P. In addition, amorphous Fe (hydr)oxides were more efficient scavengers of dissolved As than the more crystalline forms of solid-phase Fe. Given that dissolved As in the surface bay water was lower than within the subterranean estuary, our results indicate that the distribution and type of Fe and Mn (hydr)oxides in coastal aquifers exert a major influence on the biogeochemical cycling of As in subterranean estuaries and, ultimately, the fate of groundwater-derived As in marine systems influenced by SGD.

Impacts of coal-fired power plants on trace metals and polycyclic aromatic hydrocarbons (PAHs) in lake sediments in central Alberta, Canada

Abstract: Trace metals and polycyclic aromatic hydrocarbons (PAH) were analyzed in sediment cores from three central Alberta lakes to determine the contributions of local coal-fired power plants to contaminant loadings. In Wabamun Lake, with four power plants built since 1950 within a 35-km radius, sediment concentrations of mercury, copper, lead, arsenic and selenium have increased by 1.2- to 4-fold. Trace metal enrichments were less pronounced in Lac Ste. Anne and Pigeon Lake, situated 20 km north and 70 km south of Wabamun Lake, respectively. Total Hg flux to Wabamun Lake sediments (21–32μg m−2 yr−1) has increased 6-fold since 1950, compared to 2- and 1.5-fold increases in Lac Ste. Anne and Pigeon Lake, respectively, since circa 1900. Total PAH flux to surface sediments was 730–1100μg m−2 yr−1 in Wabamun Lake, 290–420μg m−2 yr−1 in Lac Ste. Anne, and 140–240μg m−2 yr−1 in Pigeon Lake. Without adoption of pollution-abatement technology that compensates for increases in generating capacity, continued expansion of coal-burning industry in Alberta will result in increased contaminant deposition, primarily from local sources.

Trace metal speciation in brackish water using diffusive gradients in thin films and ultrafiltration: comparison of techniques.

Abstract: Diffusive gradients in thin films (DGT) and ultrafiltration were used to measure trace metal concentrations in the Baltic Sea. The results provide the first comparison of these two fundamentally different speciation methods for trace metals. Cd, Cu, Mn, Ni, and Zn were measured at two sites with different total trace metal concentrations. DGT units prepared with APA-gel as diffusive layer and Chelex 100 resin as binding agent were used throughout the study. The ultrafiltration was performed with Millipore Prep/Scale modules with cutoffs of 1 and 10 kDa. Concentration levels of Mn, Zn, and Cd measured by DGT agreed with the concentrations measured in 1 kDa ultrafiltered samples. For Cu and Ni the ultrafiltered concentrations exceeded the DGT-labile concentrations. The ability of DGT to preconcentrate metals was found to be an analytical advantage compared with ultrafiltration. DGT appears to be a good alternative to 1 kDa ultrafiltration for measurement of truly dissolved Mn, Cd, and Zn in the Baltic Sea.

Particulate Air Pollution from Bushfires: Human Exposure and Possible Health Effects

Abstract: Toxicological studies have implicated trace metals adsorbed onto airborne particles as possible contributors to respiratory and/or cardiovascular inflammation. In particular, the water-soluble metal content is considered to be a harmful component of airborne particulate matter. In this work, the trace metal characteristics of airborne particulate matter, PM2.5, collected in Singapore from February to March 2005 were investigated with specific reference to their bioavailability. PM2.5 mass concentrations varied between 20.9 mug/m3 and 46.3 microg/m3 with an average mass of 32.8 microg/m3. During the sampling period, there were several bushfires in Singapore that contributed to sporadic increases in the particulate air pollution, accompanied by an acrid smell and asthma-related allergies. The aerosol samples were subjected to analysis of trace elements for determining their total concentrations as well as their water soluble fractions. Our results showed an increase in concentration of several water-soluble trace metals during bushfires compared to their urban background levels in Singapore. In order to measure the human exposure to particulate air pollution, the daily respiratory uptake (DRU) of several trace metals was calculated and compared between haze and nonhaze periods. The DRU values were significantly higher for several metals, including Zn, Cu, and Fe, during bushfires. Electron paramagnetic resonance (EPR) measurements showed that the particulate samples collected during bush fires generate more toxic hydroxyl radicals (OH.) than those in the background air, due to the presence of more soluble iron ions.

Trace metal concentrations in Posidonia oceanica of North Corsica (northwestern Mediterranean Sea): use as a biological monitor?

Abstract: Within semi-closed areas like the Mediterranean Sea, anthropic wastes tend to concentrate in the environment. Metals, in particular, are known to persist in the environment and can affect human health due to accumulation in the food chain. The seagrass Posidonia oceanica, widely found in Mediterranean coastal waters, has been chosen as a "sentinel" to quantify the distribution of such pollutants within the marine environment. Using a technique similar to dendrochronology in trees, it can act as an indicator of pollutant levels over a timeframe of several months to years. In the present study, we measured and compared the levels of eight trace metals (Cr, Ni, Cu, Zn, As, Se, Cd, and Pb) in sheaths dated by lepidochronology and in leaves of shoots sampled from P. oceanica meadows collected from six offshore sites in northern Corsica between 1988 and 2004; in the aim to determine 1) the spatial and 2) temporal variations of these metals in these areas and 3) to compared these two types of tissues. We found low trace metal concentrations with no increase over the last decade, confirming the potential use of Corsican seagrass beds as reference sites for the Mediterranean Sea. Temporal trends of trace metal concentrations in sheaths were not significant for Cr, Ni, Cu, As or Se, but Zn, Cd, and Pb levels decreased, probably due to the reduced anthropic use of these metals. Similar temporal trends between Cu levels in leaves (living tissue) and in sheaths (dead tissue) demonstrated that lepidochronology linked with Cu monitoring is effective for surveying the temporal variability of this metal. Leaves of P. oceanica can give an indication of the metal concentration in the environment over a short time period (months) with good accuracy. On the contrary, sheaths, which gave an indication of changes over long time periods (decades), seem to be less sensitive to variations in the metal concentration in the environment. Changes in human consumption of metals (e.g., the reduction of Pb in fuel) are clearly reflected in both organs. These results confirm that P. oceanica is a good bioindicator of metals and a good biomonitor species for assessing Cu in the environment.

Trophic transfer of trace metals from the polychaete worm Nereis diversicolor to the polychaete N. virens and the decapod crustacean Palaemonetes varians

Abstract: Diet is an important exposure route for the uptake of trace metals by aquatic inverte- brates, with trace metal trophic transfer depending on 2 stages—assimilation and subsequent accu- mulation by the predator. This study investigated the trophic transfer of trace metals from the sedi- ment-dwelling polychaete worm Nereis diversicolor from metal-rich estuarine sediments in southwestern UK to 2 predators—another polychaete N. virens (Cu, Zn, Pb, Cd, Fe) and the decapod crustacean Palaemonetes varians (Cu, Zn, Pb, Cd, Fe, Ag, As, Mn). N. virens showed net accumula- tion of Cu, Zn, Pb and Cd from the prey; accumulation increased with increasing prey concentration, but a coefficient of trophic transfer decreased with increasing prey concentration, probably because a higher proportion of accumulated metal in the prey is bound in less trophically available (insoluble) detoxified forms. The trace metal accumulation patterns of P. varians apparently restricted significant net accumulation of metals from the diet of N. diversicolor to just Cd. There was significant mortality of the decapods fed on the diets of metal-rich worms. Metal-rich invertebrates that have accumulated metals from the rich historical store in the sediments of particular SW England estuaries can poten- tially pass these metals along food chains, with accumulation and total food chain transfer depending on the metal assimilation efficiencies and accumulation patterns of the animal at each trophic level. This trophic transfer may be significant enough to have ecotoxicological effects.

Trophic transfer of trace metals: subcellular compartmentalization in a polychaete and assimilation by a decapod crustacean

Abstract: The chemical form of accumulated trace metal in prey is important in controlling the bioavailability of dietary metal to a predator. This study investigated the trophic transfer of radio- labelled Ag, Cd and Zn from the polychaete worm Nereis diversicolor to the decapod crustacean Palaemonetes varians. We used 2 populations of worms with different proportions of accumulated metals in different subcellular fractions as prey, and loaded the worms with radiolabelled metals either from sediment or from solution. Accumulated radiolabelled metals were fractionated into 5 components:metal-rich granules (MRG), cellular debris, organelles, metallothionein-like proteins (MTLP), and other (heat-sensitive) proteins (HSP). Assimilation efficiencies (AE) of the metals by P. varians were measured from the 4 categories of prey (i.e. 2 populations, radiolabelled from sediment or solution). There were significant differences for each metal between the AEs from the different prey categories, confirming that origin of prey and route of uptake of accumulated trace metal will cause intraspecific differences in subsequent metal assimilation. Correlations were sought between AEs and selected fractions or combinations of fractions of metals in the prey-MRG, Trophically Avail- able Metal (TAM = MTLP + HSP + organelles) and total protein (MTLP + HSP). TAM explained 28% of the variance in AEs for Ag, but no consistent relationships emerged between AEs and TAM or total protein when the metals were considered separately. AEs did, however, show significant positive regressions with both TAM and total protein when the 3 metals were considered together, explain- ing only about 21% of the variance in each case. A significant negative relationship was observed between MRG and AE for all metals combined. The predator (P. varians) can assimilate dietary metal from a range of the fractions binding metals in the prey (N. diversicolor), with different assimilation efficiencies summated across these fractions. TAM and/or total protein may represent an approxi- mate minimum for trophic availability but neither of these alone is a fully accurate predictor.

A suitable model for the biomonitoring of trace metal bioavailabilities in estuarine sediments : the annelid polychaete Nereis diversicolor

Abstract: The need to use biomonitors representative of the sedimentary compartment has been recognized, particularly in estuaries. Thus, trace metal contamination has been monitored in an infaunal polychaete worm Nereis diversicolor and sediments in the Seine estuary and comparatively in the relatively clean Authie estuary (French coast of the English Channel) over two years taking samples every three months at both sites. No correlations were shown between total metal (Ag, Cd, Cu, Pb, Zn) concentrations in raw sediments and ragworms. Because these worms are known to be good biomonitors of the bioavailabilities of sedimentary trace metals, it follows that total sediment metal concentrations have a poor predictive ecotoxicological value. Using a correction factor to minimize the influence of weight, it is possible to make a good estimation of the average metal concentrations in a population of worms at a given site, sampling only a limited number of specimens. Metallothioneins are often considered to be good biomarkers of the presence of significant availabilities of trace metals. Metallothionein-like proteins (MTLPs) are present in N. diversicolor, but there is no significant relationship between MTLPs and metal concentrations. This situation might result from the importance of metal-containing granules, both extra- and intracellular, in ragworms.

Factors Controlling the Geochemical Partitioning of Trace Metals in Estuarine Sediments

Abstract: The geochemical partitioning of trace metals in sediments is of great importance in risk assessment and remedial investigation. Selected factors that may control the partitioning behavior of Cu, Pb and Zn in non-sulfidic, estuarine sediments were examined with the use of combined sorption curve—sequential extraction analysis. This approach, which has not been previously used to examine estuarine sediments, allowed determination of sorption parameters for Cu, Pb and Zn partitioning to individual geochemical fractions. Partitioning behavior in sulfidic sediments was also determined by sequentially extracting Cu, Pb, and Zn from synthetic sulfide minerals and from natural sediment and pure quartz sand after spiking with acid-volatile sulfide (AVS). Trace metal sorption to the “carbonate” fraction (pH 5, NaOAc extraction) increased with metal loading due to saturation of sorption sites associated with the “Fe-oxide” (NH2OH·HCl extraction) and “organic” (H2O2 extraction) fractions in non-sulfidic sediments. Fr...