Deposition Of Trace Metals Research Articles

Dry deposition fluxes and deposition velocities of trace metals in the Tokyo metropolitan area measured with a water surface sampler.

Dry deposition fluxes and deposition velocities (=deposition flux/atmospheric concentration) for trace metals including Hg, Cd, Cu, Mn, Pb, and Zn in the Tokyo metropolitan area were measured using an improved water surface sampler. Mercury is deposited on the water surface in both gaseous (reactive gaseous mercury, RGM) and particulate (particulate mercury, Hg(p)) forms. The results based on 1 yr observations found that dry deposition plays a significant if not dominant role in trace metal deposition in this urban area, contributing fluxes ranging from 0.46 (Cd) to 3.0 (Zn) times those of concurrent wet deposition fluxes. The deposition velocities were found to be dependent on the deposition of coarse particles larger than approximately 5 microm in diameter on the basis of model calculations. Our analysis suggests that the 84.13% diameter is a more appropriate index for each deposited metal than the 50% diameter in the assumed undersize log-normal distribution, because larger particles are responsible for the flux. The deposition velocities for trace metals other than mercury increased exponentially with an increase in their 84.13% diameters. Using this regression equation, the deposition velocities for Hg(p) were estimated from its 84.13% diameter. The deposition fluxes for Hg(p) calculated from the estimated velocities tended to be close to the mercury fluxes measured with the water surface sampler during the study periods except during summer.

A consideration of potential confounding factors limiting chemical and biological recovery at Lochnagar, a remote mountain loch in Scotland

Lochnagar, a remote loch in the Grampian Mountains of Scotland is one of the most studied freshwater bodies in the UK. It represents a key site in a number of monitoring programmes and has become the UK’s 'flag-ship' mountain lake in various EU funded projects over the last 15 years. Palaeolimnological studies have revealed the extent and diverse provenance of atmospherically deposited pollution at the site and show that the loch began to acidify in the mid-19th century. However, despite abatement strategies dramatically reducing the emission and deposition of non-marine sulphate and trace metals since the 1970s, the loch pH shows little sign of recovery and full basin fluxes of, for example, Pb and Hg show no decline or even a continued increase. It is suggested that the lack of recovery from acidification over the last 15 years of monitoring results from the balancing of the decline in sulphate by increased nitrate, and that this increase is related to winter duration and severity. The lack of response by the sediment record to declines in metal deposition is thought to be due to a continuing input of previously deposited metals from the catchment. Hypotheses for these enhanced catchment inputs involve responses to a changing climate. Site specific climate reconstructions and predictions for the 21st century suggest an accelerated increase in temperature rise and increased winter precipitation and storminess. These predicted changes are likely to exacerbate the input of metals (and other stored pollutants) from the catchment but higher temperatures may also help to promote recovery from acidification.

Determination of metallic pollutants in atmospheric particles, wet deposition and epiphytic lichens in the Pyrénées mountains (Aspe Valley)

The purpose of this study is to investigate the emission and deposition of trace metals released by road traffic in the Aspe Valley in the french Pyrenees mountains. Sampling and analytical procedure have been developed for Li, Mg, V, Cr, Mn, Cu, Zn, Rb, Cd, Sn, Sb, Ba, Ce and Pb analyses were performed on certified reference materials to validate the measurement with Q-ICP-MS and HR-ICP-MS. The determination of Pb isotopic ratio was also validated on NIST SRM981. Aerosol, snow, rainwater and lichens samples were collected with ultra-clean conditions during winter 2001 and summer 2002. Preliminary results are presented for lichen and snow samples.

Heavy metal deposition and cycling at two Mediterranean holm oak (Quercus ilexL.) forests in northeastern Spain

Trace metal deposition in precipitation was not significantly different in two holm oak forests with contrasted exposure to pollution in the area around Barcelona (Northeastern Spain), but dry deposition was higher at the more exposed site. Rain events of European origin had higher concentrations of Cu, Pb, Zn and Cd than those from African, Atlantic Ocean and Local provenances. Estimated from the recovered quantities in artificial plates, dry deposition was, for Zn, Cu and Pb: 342, 25 and 20 g ha -1 yr -1 , respectively at the exposed site, and 254, 13 and 15 g ha -1 yr -1 at the sheltered one. Deposition in bulk precipitation was lower than dry deposition: 221, 6. 2 and 6.4 g ha -1 yr -1 for Zn, Cu and Pb, respectively (average of the two sties).

Dry deposition of airborne trace metals on the Los Angeles Basin and adjacent coastal waters

We present an assessment of the deposition rates of airborne trace metals onto the Los Angeles Basin and adjacent coastal waters. For this purpose, the UCLA Surface Meteorology and Ozone Generation (SMOG) air pollution modeling system has been used to simulate the geographical distributions of trace metals and their deposition fluxes. Calculations were performed for average summer and winter conditions, as well as for extreme meteorological events, in particular, for Santa Ana winds. Thus, a series of simulations were carried out that define the range of meteorological conditions contributing to dry deposition in the region. These predictions have been calibrated and validated using measurements collected in the LA area. Significant spatial and temporal variability are found in trace metal concentrations and deposition rates. Large spatial gradients occur near the coast as well as at the mountainous boundaries of the airshed. Considerable diurnal and seasonal variations in trace metal deposition are also noted. For example, the development of a daytime sea breeze, particularly in the warmer months, leads to greater deposition in the northern and eastern basin as well as in the high desert. A nighttime land breeze, especially in the colder months, enhances deposition onto coastal ocean surfaces. Large particles dominate local trace metal deposition in central urban (and adjacent) areas, while fine particles export metals over regional scales through long‐range advection. Since the majority of urban metal deposition occurs on particles larger than 10‐μm diameter, routine measurements of PM10 or PM2.5 concentrations for air quality characterization may not be reliable indicators of local sources. Some 35–45% of all trace metal emissions are deposited locally within the Los Angeles Basin on an annual basis. Santa Monica Bay and its watersheds receive about 6% of this amount, which can have a significant impact on trace metal concentrations in the surface waters of the bay, primarily through land runoff following storms.

Wet Deposition of Trace Metals in Singapore

The concentrations of 12 trace metals (Al, Cd, Cr, Cu, Co, Fe,Mn, Ni, Pb, Zn, V, and Ti) in wet depositions are reported. Eighty four rainwater samples were collected using an automated wet-only sampler in Singapore for one year (2000) and subjected to chemical analysis using ICP-MS. Based on the volume-weighted meanconcentrations measured, the trace metals were classified into three groups: Al and Fe with an average concentration of largerthan 15 μg L-1, Cr, Cu, Mn, Ni, Pb, Zn, V, and Ti withconcentrations between 1 and 10 μg L-1, and finally Co and Cd with concentrations lower than 1 μg L-1. Elementenrichment factors were calculated to distinguish between naturaland anthropogenic sources. The calculation of crustal enrichmentfactors with Al as the reference element indicated that while Ti,Fe and Mn originated from crustal sources, the remaining trace metals (Cd, Cr, Co, Cu, Ni, Pb, Zn and V) were mainly derived from anthropogenic sources. The removal of the trace metals from the atmosphere by precipitation was influenced by the rainfall amount as well as pH. The magnitude of the measured average annual wet deposition fluxes of Al, Fe, and combustion-generatedelements such as V, Ni, and Cu is higher than that reportedfor other sites outside Singapore, owing to abundant rainfallthroughout the year in this region.

Atmospheric deposition of major ions and trace metals near an industrial area, Jordan.

Al, Cd, Cr, Cu, Fe, Mn, Pb, Zn, NH4+, Mg2+, Ca2+, Na+, K+, Cl-, NO3- and SO4(2-), along with pH were determined in wet and dry deposition samples collected at Al-Hashimya, Jordan. Mean trace metal concentrations were similar or less than those reported for other urban regions worldwide, while concentrations of Ca2+ and SO4(2-) were the highest. The high Ca2+ concentrations were attributed to the calcareous nature of the local soil and to the influence of the Saharan dust, while the high concentrations of SO4(2-) were attributed to the influence of anthropogenic sources and Saharan dust soil. Except for SO4(2-), NO3-, and Ca2+, dry deposition fluxes of measured metals and ions were higher than their corresponding wet deposition fluxes. The high annual average pH values recorded for wet and dry deposition samples were attributed to the neutralization of acidity by alkaline species. Cd, Cr, Cu, Pb, Zn, NO3- and SO4(2-) were enriched in wet and dry deposition samples relative to crustal material, and a significant anthropogenic contribution to these elements and ions is tentatively suggested. Finally, the possible sources and the main factors affecting the concentrations of the measured species are discussed.

You can take the genome out of the organism, but can you take the organism out of the environment?

In a debate held on July 28th in Cincinnati, a new chapter in the nature versus nurture saga was initiated. The premise under discussion was whether nonfamilial, i.e. sporadic, Alzheimer disease (AD) is primarily a genetic disorder. The participants took the position that either A) genetic factors are largely responsible for the so-called sporadic cases of AD or B) environmental factors contribute to the development of sporadic AD. The argument that genetic factors result in sporadic AD was based on population based studies such as the Nun study and twin studies. The participants correctly point out the more than passing role of the APOE-e4 in the development of Alzheimer disease. In addition, a wide variety of genes and chromosomal loci have been implicated in the development of Alzheimer disease. However, although twin studies, for example, indicate a heritability of greater than 60% it is not 100%. The typical argument employed to explain this type of discrepancy is that when age corrected we get much closer since one of the siblings may die of other causes before having the “opportunity” to develop Alzheimer disease. While admitting that diet and other health related activities may influence the development of Alzheimer disease they maintain their position that non-familial Alzheimer disease is largely the result of genetics. On the other hand, the other participants argue that non-genetic factors play an important role in nonfamilial Alzheimer disease. Some of the possible factors include viruses, dietary components and metals. The unifying feature is postulated to be inflammation resulting from any of these insults. Special attention was paid to the role of aluminum, which has long been conjectured to facilitate the development of Alzheimer disease. In addition, the role of diet and especially dietary fats were discussed. With the increasing evidence of oxidative stress in the etiology of Alzheimer disease, the authors also consider the role of trace metal deposition through dietary exposure. Finally, increasing evidence in a number of chronic conditions has implicated bacterial and viral pathogens as underlying components in disease etiology. HSV-1 has been implicated as a potential underlying component in Alzheimer disease. Thus, these authors hold that environmental concerns play a large role in the development of Alzheimer disease and moreover are more tractable to intervention that are genetic predispositions. So, what can we take away from this? It is clear that genetic predisposition is important in the development of disease and that the development of disease can be modified by controlling external influences, i.e. cholesterol uptake. However, the important issue from the perspective of the prospective patient, current patient, or family members is what can we predict about the natural history of the individual. The studies listed

In-stack emissions of heavy metals estimated by moss biomonitoring method and snow-pack analysis

Data from the chemical analysis of moss growing close to a thermal power station and snowpack have been used for the estimation of heavy metal deposition close to the point pollution sources. A semi-empirical model was proposed to describe atmospheric trace metal deposition close to the point pollution source. Model parameters were derived from experimental data, and nickel and vanadium quantities, washed out with snow and rain, were calculated. Using long-term meteorological observation data of rain and snow duration and metal uptake efficiencies in moss, the average emission rates of vanadium and nickel from the stack were calculated. The coincidence between data from emission inventory and model results was within 25%. It was estimated that in the vicinity of pollution source (within 30 km) about 15% out of total emitted metals were washed out by rain and snow events. Metal concentrations in the environment become indistinguishable from the background at a distance of about 20 km from the stack.

The historical record of PAH, PCB, trace metal and fly-ash particle deposition at a remote lake in north-west Scotland

Sediment cores taken from the deep basin of Loch Coire nan Arr in north-west Scotland were dated using 210Pb calibrated spheroidal carbonaceous particle (SCP) profiles and analysed for trace metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). These data show that the site is one of the least contaminated by atmospheric pollution in the UK. Peak concentrations of PAHs were found to be equivalent to background values at sites in the English Lake District. The date of concentration maxima for SCP, PCB and some metals were in agreement with previously published polychlorinated dibenzo-p-dioxin/polychlorinated dibenzofuran (PCDD/F) data suggesting long-range industrial sources. The date of individual PAH concentration maxima were earlier, but concomitant with each other, possibly suggesting the influence of a local source. Comparison with remote European mountain lakes shows Loch Coire nan Arr to be one of the least contaminated sites in Europe with respect to PCBs, but more contaminated with respect to PAHs.

Leaching of Nutrients and Trace Metals from Aerosol Samples; A Comparison Between A Re-Circulation and an Ultrasound System

As part of a project investigating the air-water exchange of nutrients and inorganic micropollutants to the North Sea, the atmospheric deposition of nutrients and trace metals in their different compositions and via various pathways was investigated. Intensive sampling campaigns were organised on the research vessel Belgica (ns 21/98 campaign from September 28 to October 1, 1998 and ns 10/99 campaign from April 19 to 23, 1999), at a sampling station near the Belgian coast (Knokke-Heist) and at the University campus of Antwerp. Simulation work and remobilisation experiments were carried out to obtain a general view of the kinetics of solubilisation of the constituents under investigation. Sample treatment requires a leaching system with a quantitative recovery of the species of interest in the leaching solution within a reasonably short period of time (30 min). For this reason, a re-circulation leaching system was developed, tested, optimised and compared with a more accepted ultrasound leaching method.

Use of atomic absorption spectrometry for the determination of metals in sediments in south-west Louisiana

The relatively recent introduction of atomic absorption spectrometry has produced a rapid and relatively inexpensive method for the determination of metal concentrations in a wide variety of samples. One such application is in the determination of metal concentrations in soils and sediments. Soils and sediments represent concentrated reservoirs for these metals that serve as sinks for introduced trace metals or can become environmental sources. The coastal zone of Louisiana provides a ‘living laboratory’ to investigate the mechanisms of transport, deposition, and dissolution of trace metals into this fragile environment. Investigations done in the coastal zone have found trace metals tend to concentrate near pollution inputs and sources and have not migrated to or significantly impacted the coastal zone of Louisiana. Common trace metals determined and their range of concentrations in coastal soil and sediments are chromium (10–30 ppm), copper (10–25 ppm), iron (0.6–2.1%), manganese (200–600 ppm), nickel (6–20 ppm), lead (8–20 ppm), and zinc (30–55 ppm).

Metal Concentrations in Soils and Sediments in Southwest Louisiana

ABSTRACT Soils and sediments represent concentrated reservoirs for metals that serve as sinks for introduced trace metals or can become environmental sources. The coastal zone of Louisiana provides a “living laboratory” to investigate the mechanisms of transport, deposition, and dissolution of trace metals into this fragile environment. Common trace metals determined and their range of concentrations in soil and sediments are chromium (10-30 (parts per million) (ppm)), copper (10-25 ppm), iron (0.6-2.1 %), manganese (200-600 ppm), nickel (6-20 ppm), lead (8-20 ppm), and zinc (30-55 ppm).

ATMOSPHERIC DEPOSITION AND RUNOFF OF MERCURY AND TRACE METAL IN AN URBAN WATERSHED

Non-point and diffuse sources can be the most significant sources of pollutants in a watershed. Atmospheric deposition in its three forms (ambient, dry, and wet) has often been neglected and thus was not included in watershed approach for water resources management. Often regulatory frameworks for water resources protection have not taken into account atmospheric deposition because little or no data is available. The project undertaken is new and unique in its scope and approach to monitor and measure pollutants in atmospheric deposition and its impact on storm water quality within a river watershed. Specialized sampling equipment and ultra-clean analytical methodology were employed to quantify the concentrations or masses in ambient air, precipitation, and runoff for twelve trace metals. These metals include mercury (Hg), cadmium (Cd), antimony (Sb), aluminum (Al), arsenic (As), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn). Meteorological parameters including wind speed, wind direction, temperature, and relative humidity were also measured. This study represents the most complete set of atmospheric concentration and deposition data for trace metals and mercury in an urban watershed at this time. Additionally, this is the first time that mercury together with other trace elements in dry deposition and runoff has been measured in a study of this length. The results of this study provide both the critical information and valuable study approaches to monitor trace metal deposition in urban watersheds.

Wet deposition of trace metals to a remote site in Fiordland, New Zealand

Cd, Cu, Fe, Mn, Pb, Zn, Ca, Mg, Na, pH, and 210 Pb were determined in rainwater collected at Paradise, a remote site in Fiordland, New Zealand, to evaluate sources and fluxes of atmospheric trace metals in the NZ region of the South Pacific westerlies. Individual rain events were sampled using rigorous trace metal clean protocols during 1993–1995. Air-mass trajectories showed an Australian and Southern Ocean influence on most samples. Ca, Mg, and Na were highly correlated with each other, over 2–3 orders of magnitude, and had a sea-salt aerosol source. Most of the Fe was not soluble in 0.03 M nitric acid after 48 h, suggesting low bioavailability after deposition to the ocean, whereas most of the Zn was soluble. Mean trace metal concentrations were similar to those at other Southern Hemisphere sites; with the lower concentrations comparable with those in present-day Antarctic snow. Trace metal concentrations spanned two orders of magnitude, and were not obviously related to air-mass trajectories. The seawater contribution to rainwater trace metals was negligible. Cd, Cu, Pb, and Zn were enriched in rainwater relative to crustal material, and a significant anthropogenic contribution to these elements is tentatively suggested. Limited Pb isotope data link anthropogenic Pb with high Pb enrichment. Cd, Pb, Zn, and H + were correlated with each other, suggesting a common source. Fe and Mn were correlated, and had a predominantly crustal dust source. Cd and Pb were correlated with 210 Pb , implying that these metals were associated with submicrometre-sized aerosols.

The trace metal chemistry of atmospheric dry deposition samples collected at Cap Ferrat: a coastal site in the Western Mediterranean

A series of 10 dry deposition samples were collected on a surrogate plate over a period of 8 months at Cap Ferrat, a site on the Western Mediterranean coast, and analysed for Al, Fe, Mn, Ni, Co, Cr, Cu, Zn and Pb. Relatively few data sets for trace metal dry deposition are available in the literature, and considerable difficulties are inherent in the use of surrogate plates for the collection of dry deposition. However, the trace metal chemistry of the plate-collected dry deposition at the Cap Ferrat site generally mimics the trends predicted from theoretical metal deposition velocities. The dry deposition is dominated by the fall-out of larger-size particles and during the parent aerosol→dry deposition sequence there is a strong, particle size-mediated, fractionation of the crust-dominated, non-enriched elements (NEEs) from the anthropogenic-dominated, anomalously enriched elements (AEEs), with the latter being depleted in the dry deposition. As a result, although the AEEs in the dry deposition are still enriched relative to average crustal material, the dry deposition and the parent aerosols have different `chemical characters'. Further, the dry deposition has a more homogenous trace metal composition than the parent aerosol. The depletion of the AEEs in the dry deposition, relative to the parent aerosol, has important implications for sea water solubilisation. To assess this, a technique is outlined which allows the solubilities of Cu, Zn and Pb to be estimated on the basis of their EFcrust values in atmospheric particulates. The technique reveals that the solubilities of Cu, Zn and Pb from the dry deposition are less than those which would be predicted from data on the parent aerosol. A comparison between the dry and wet trace metal deposition fluxes at the Cap Ferrat site shows that the particulate fraction dominates the dry deposition of all the metals. However, in wet deposition Cu and Pb switch character and the soluble fraction becomes dominant.

Monitoring historical changes in soil and atmospheric trace metal levels by dendrochemical analysis

The use of dendrochemistry for monitoring historical changes in trace metal deposition and mobilisation of metals in soils is evaluated. In experimental studies, mobilisation of trace metals in surface soil following deliberate acidification was recorded in sugar maple (Acer saccharum) tree-rings with minimal lateral movement between rings. Furthermore, positive correlations between wood (3 year section 1993–95) and foliar chemistry (mean concentration 1993–95) were found for Cd and Zn, but not for Cu and Ni, showing that mobility up the tree bole differs between metals. Even so, substantial lateral movement of elements between rings occurs in some species. Stable Pb isotope ratios in tree-rings were used to show that sacred fir (Abies religeosa) is not a useful monitor of Pb deposition because Pb accumulates in the heartwood. Numerous sophisticated analytical techniques are now used in dendrochemical studies, including laser ablation sampling in conjunction with inductively coupled plasma mass spectrometry that enable the multi-element analysis of extremely small tree-rings with low detection limits. Clearly, not all tree species are suitable for dendrochemical studies, but if careful sampling strategies are used and suitable tree species are chosen, the chemical analysis of tree-rings can provide information concerning historical changes in soil and atmospheric trace metal levels unavailable from any other source.

Change in the dendrochemistry of sacred fir close to Mexico City over the past 100 years

The chemistry of the tree-rings of sacred fir ( Abies religiosa) growing in the high elevation forest park, Desierto de los Leones, close to Mexico City was measured in 5 year increments dating back to 1897. Surface soil beneath sampled trees had elevated concentrations of trace metals, especially Pb, Cd and Zn, compared with a reference site at San Pablo 45 km upwind of Mexico City. High metal concentrations were associated with low soil pH. Lead and Cd increased in tree-rings formed since the 1960s, reflecting the increase in urbanization and vehicle numbers in Mexico City. Small increases in Cu and Ni during this period appear to be a natural occurrence, as similar changes were found at San Pablo. Peaks in Cd and most obviously Pb, were found in rings formed in the period 1920–1940 corresponding to the heartwood–sapwood boundary, but were most apparent in trees growing in contaminated soils with low pH. It is suggested that Pb and Cd taken up by roots of sacred fir accumulate in the heartwood, whereas Pb and Cd entering through bark are transported radially to a much lesser extent and more accurately record changes in trace metal deposition.

Atmospheric deposition of trace metals at three sites near the great lakes

The concentrations of vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb) in precipitation and on airborne particles were measured at three Integrated Atmospheric Deposition Network (IADN) monitoring stations on Lakes Superior, Michigan and Erie during 1993 and 1994. These data were used to estimate annual wet and dry deposition fluxes at these sites. In most cases, both wet and dry deposition make an important contribution to the total atmospheric flux of trace metals. Total (wet + dry) annual loadings of Zn and Cr are higher at the Lake Erie site than at the Lake Michigan and Lake Superior sites. Atmospheric loadings of the other metals are similar at all three sites. Wet deposition of metals is more closely related to precipitation amount than to the concentration of metals in the precipitation. Dry deposition fluxes are controlled by the concentration of trace metals on large particles. Total particle mass concentrations are higher during the summer and fall at the Lake Erie site, however no seasonal trends in total particle mass at the other sites or trace metals at any of the sites were detected. The total atmospheric loadings calculated in this work are in agreement with other estimates of metals deposition to the Great Lakes.

An evaluation of the use of dendrochemical analyses in environmental monitoring

Dendrochemical techniques have been used to monitor historical changes in soil and atmospheric chemistry since the early 1970s. The development of dendrochemistry in environmental monitoring was prompted by early studies which reported that changes in Pb deposition along roadsides and in industrial areas were reflected by changes in the Pb content of tree rings. Early studies were inconclusive; some authors have stated that tree-ring chemistry is not a useful indicator of pollution episodes and that some tree species are clearly better spatial indicators of pollution than historical monitors. This is due to a number of complicating factors, including potential radial translocation of elements, radial tendencies in element concentration from pith to bark, and physiological differences between heartwood and sapwood. A more detailed understanding of element cycling in trees is needed, as at present, the application of dendrochemistry to historical environmental monitoring is strongly dependent on the choice of tree species and the elements to be studied. There is no general consensus as to which tree species are best suited for dendrochemical studies. There are many reports in which the analyses of tree-ring chemistry have been successfully used to reconstruct trace-metal deposition from a variety of sources, including automobiles, metal refineries, and coal burning. Changes in tree-ring chemistry in recent decades have coincided with hypothesized changes in soil chemistry believed to be a result of acidic deposition onto poorly buffered soils. Indications of changes in groundwater quality, volcanic eruptions, and even climate change have been reported to be preserved in the chemical composition of tree rings. An improvement in analytical techniques has allowed multielement analysis on whole wood samples, with very low detection limits and extremely high spatial resolution, enabling intra-annual changes in element composition of tree rings to be determined. The application of dendrochemistry in environmental monitoring is promising, and with a more detailed understanding of nutrient and metal cycling in trees, dendrochemical studies will continue to provide useful information on historical pollution loadings and changes in soil and atmospheric chemistry that is unobtainable from any other source.