Trace Elements in the Atmospheric Environment

Environmental significance of trace elements in the Athabasca Bituminous Sands: facts and misconceptions

The bituminous sands of Alberta, Canada, represent the second largest reserves of hydrocarbons on earth. Open pit bitumen mining and upgrading of the Athabasca Bituminous Sands (ABS), the largest of the deposits, began in 1967. Concerns about fugitive release of trace elements (TEs) to the environment began with studies of V, as this is the most abundant trace metal in bitumen. Recent studies, however, have extended to Ag, As, Be, Cd, Cr, Cu, Pb, Sb, and Tl, and this has led to considerable confusion about which TEs are relevant to ecosystem health. While V along with Ni, Mo, Se and Re are enriched in bitumen, Ag, As, Be, Cd, Cr, Cu, Pb, Sb and Tl are found almost exclusively in the mineral (i.e. sand) fraction of the ABS, with limited opportunity to become bioaccessible, much less bioavailable. Here, a summary is given of ten misunderstandings that have arisen regarding TEs in the environment of the ABS region. To help illustrate the significance of the misconceptions that have arisen regarding (a) air and (b) water resources, published and unpublished TE data obtained from the metal-free, ultraclean SWAMP lab is presented for: (a) snow, moss, and peat cores from bogs, and (b) the dissolved, particulate, and colloidal fractions of water from the Athabasca River (AR), as well as pristine groundwater. Natural enrichments of Ni in plants such as Rat Root (Acorus calamus) and pine (Pinus banksiana), Tl in fish (Percopsis omiscomaycus) and Cd in cranberries (Vaccinium oxycoccus), Labrador Tea (Rhododendron groenlandicum) and beaver (Castor canadensis), are also presented.

Exposure profiles of workers from indium tin oxide target manufacturing and recycling factories in Taiwan

Indium tin oxide exposure poses a potential health risk, but the exposure assessment in occupational setting remains incomplete and continues to be a significant challenge. To this end, we investigated the association of work type, airborne indium concentration, respirable fraction of total indium, and cumulative indium exposure index (CEI) with the levels of plasma indium (P-In) and urinary indium (U-In) among 302 indium tin oxide target manufacturing and recycling workers in Taiwan. We observed that recycling-crushing produced the highest concentrations of total indium (area: 2084.8 μg/m³; personal: 3494.5 μg/m³) and respirable indium (area: 533.4 μg/m³; personal: 742.0 μg/m³). Powdering produced the highest respirable fraction of total indium (area: 58.6%; personal: 81.5%), where the workers had the highest levels of P-In (geometric mean: 2.0 μg/L) and U-In (1.0 μg/g creatinine). After adjusting for the confounder, the CEIs of powdering (β_PR = 0.78; β_PR = 0.44), bonding (β_PT = 0.61; β_PT = 0.37), and processing workers (β_PT = 0.43; β_PT = 0.28) showed significant associations with P-In and U-In, validating its utility in monitoring the exposure. Also, the respirable fraction of total indium significantly contributed to the increased levels of P-In and U-In among workers. The varying levels of relationship noted between indium exposure and the levels of P-In and U-In among workers with different work types suggested that setting the exposure limits among different work types is warranted.

Rainwater characteristics and interaction with atmospheric particle matter transportation analyzed by remote sensing around Beijing

Air pollution in Beijing has attracted much more attentions, and multiple regulations have been enacted since 2013. Based on the close link between the atmospheric particle matter concentration and the deposited load in rainwater, 336 rainwater samplings with seven parameters (pH, NH₄⁺-N, NO₃^--N, P, S, Cu and Cd) at five-minute intervals in 2013 and 2014 were compared. The field monitoring and the temporal patterns analysis revealed a positive development of air quality. The lesser composition of coal in the energy consumption and the effective control of traffic emission were found. The average Aerosol Optical Depth (AOD) value around the sampling point during the 7 sampling rainfall events in 2014 was 2.855, which was higher than that in 2013 (1.807). It reflected the washing effect of rain on atmospheric particulates and highlighted the urban non-point source pollution effected by atmospheric deposition. AOD was demonstrated to perform well in reflecting regional air quality. A trajectory analysis conducted by HYSPLIT model in conjunction with the spatial distribution of AOD in the Beijing-Tian-Hebei (BTH) region depicted paths of air pollutants from long-range transport. The dominant trace was to the south of region. Cities around BTH were provided with different emission-reducing targets. Both Inner Mongolia and Henan province were suggested to control agricultural emissions. Shanxi, Shandong and cities around Bohai Bay should supervise the energy consuming industries. Furthermore, NO₃^--N was introduced to be an indicator of effect of the regional joint prevention and control in the future.

Origin and distribution of trace elements in high-elevation precipitation in southern China

INTRODUCTION

During a 2009 investigation of the transport and deposition of trace elements in southern China, 37 event-based precipitation samples were collected at an observatory on Mount Heng, China (1,269 m asl).

METHODS

Concentrations of trace elements were analyzed using inductively coupled plasma-mass spectrometry and the wet deposition fluxes were established. A combination of techniques including enrichment factor analysis, principal component analysis, and back trajectory models were used to identify pollutant sources.

RESULTS

Trace element concentrations at Mount Heng were among the highest with respect to measured values reported elsewhere. All elements were of non-marine origin. The elements Pb, As, Cu, Se, and Cd were anthropogenic, while Fe, Cr, V, Ba, Mn, and Ni were of mixed crustal/anthropogenic origin. The crustal and anthropogenic contributions of trace elements were 12.8 % (0.9 ~ 17.4 %) and 87.2 % (82.6 ~ 99.1 %), with the maximum crustal fraction being 17.4 % for Fe. Coal combustion, soil and road dust, metallurgical processes, and industrial activities contributed to the element composition.

CONCLUSIONS

Summit precipitation events were primarily distant in origin. Medium- to long-range transport of trace elements from the Yangtze River Delta and northern China played an important role in wet deposition at Mount Heng, while air masses from south or southeast of the station were generally low in trace element concentrations.

Trace element deposition and trends during a ten year period in Finland

The deposition of aluminium, arsenic, cadmium, chromium, copper, iron, lead, manganese, nickel, vanadium and zinc in bulk precipitation was examined at eight background stations in Finland during the last 10 years (1998-2007). The annual deposition was from the lowest values to the highest Cd<As<Cr<Ni<V<Cu and Pb<Mn<Zn<Al<Fe. Most of the elements had a south to north decreasing gradient mainly due to minor domestic emissions in the north, growing distance to the large European source areas and differences in the length of snow-cover period. Element enrichment factors divided the trace elements to the following categories: (1) slightly enriched Cr, Fe and Mn; (2) moderately enriched Cu, Ni and V; and (3) highly enriched As, Cd, Pb and Zn. Trend analysis of annual depositions showed that the established decreasing trend in As and Pb deposition continued during our study period while Cr, Cu and Fe depositions have lately increased. No statistically significant trends were detected for Cd, Mn, Ni, V and Zn during the studied years. Additionally, the measurement uncertainty of trace elements was evaluated for the whole measurement chain.

Studies of spatial and temporal distribution characteristics of TSP-bound trace metals in Seoul, Korea

In the present study, TSP-bound metal concentrations were measured from seven different urbanized locations in Seoul, Korea for the period from March 2001 through May 2002. Our measurement data were analyzed to explore the possible influences of spatial and temporal factors on metal distribution characteristics. To determine the importance of those aspects, the measured concentrations were compared between different metals and between different sites in terms of several criteria: (1) absolute concentrations and enrichment factor (EF) values; (2) coefficient of variation (CV) values of metal concentrations; (3) relative patterns of temporal variations; and (4) relative abundance of strong correlations. According to our analysis of metal distribution characteristics in the study area, the main results of our study can be summarized as follows: (1) a number of metals (e.g., Cd, Cu, and Pb) are highly enriched relative to the average crustal ratios (to Fe); (2) the behavior of Cu is found to vary irregularly, while Fe, Mn, and Pb are tightly coupled both spatially and temporally in the study area; (3) for most elements except Cu and Cd, seasonal variations are observed in a systematic manner; and (4) when compared against those observed in other parts of the world, our Cu and Cd concentrations observed in many locations of Seoul are notably high. The overall results of our study suggest that the distribution characteristics of metals can be regulated strongly by spatial and temporal factors and that such controls are distinguished very clearly between different metal types.

Measurements of particulate matter within the framework of the European Monitoring and Evaluation Programme (EMEP) I. First results

Particulate matter (PM) monitoring presents a new challenge to the transboundary air pollution strategies in Europe. Evidence for the role of long-range transport of particulate matter and its significant association with a wide range of adverse health effects has urged for the inclusion of particulate matter within the European Monitoring and Evaluation Programme (EMEP) framework. Here we review available data on PM physico-chemical characteristics within the EMEP framework. In addition we identify future research needs for the characterisation of the background PM in Europe that include detailed harmonised measurements of mass, size and chemical composition (mass closure) of the ambient aerosol.

Single particle and inorganic characterization of rainwater collected above the North Sea

Suspended matter and the dissolved fraction of rainwater collected above the North Sea were characterized using electron probe X-ray microanalysis (EPXMA), inductively coupled plasma-optical emission spectrometry (ICP-OES) and ion chromatography (IC), respectively. Suspended particulate matter was dominated by aluminosilicates and organic particles. Fifteen particle types describe the composition of the North Sea rainwater suspended matter. Factor analysis, particle size distributions and manual EPXMA measurements illustrated the complex genesis of different particle types: terrigenous; biogenic (both marine and continental); and anthropogenic. It was demonstrated that at the beginning of a shower of rain the coarse particles that are present in the air under the cloud are washed out, while during the second phase rainout particles, formed in the cloud, become more important due to the absence of new coarse particles under the cloud. Above the sea, the total amount of suspended matter (TSM) is much smaller and more variable than above the land and also the decrease in particle diameter is less visible. Approximately 10% of the studied particles contained trace heavy metals. The dissolved compounds in the North Sea rainwater were also variable in time and space. In general, over a short period of time, the concentrations of all dissolved compounds seem to decrease during a shower, but this decrease is much larger above land than above sea. The concentrations of dissolved trace metals present in rainwater above the southern North Sea has decreased over the last 15 years.

Volcanic and anthropogenic contribution to heavy metal content in lichens from Mt. Etna and Vulcano island (Sicily)

Major and trace element concentrations were determined in two lichen species (Parmelia conspersa and Xanthoria calcicola) from the island of Vulcano and all around Mt. Etna. In both areas, the average concentrations of Al, Ca, Mg, Fe, Na, K, P and Ti are substantially greater than those of other elements. Several elements (Br, Pb, Sb, Au, Zn, Cu) resulted enriched with respect to the local substrates. The Br and Pb enrichment factors turned out to be the highest among those calculated in both areas. Data indicate that mixing between volcanic and automotive-produced particles clearly explains the range of Pb/Br shown by lichen samples. Sb is also enriched, revealing a geogenic origin at Vulcano and a prevailing anthropic origin at Mt. Etna. Distribution maps of the enrichment factors show a generalized enrichment of Au and Zn near Mt. Etna, whereas Cu appears to be enriched prevalently in the NE-SE area. The highest levels of Au and Cu at Vulcano occur E-SE from the craters, following the prevailing wind direction.

Environmental variables in a holistic evaluation of land contaminated by historic mine wastes: a study of multi-element mine wastes in West Devon, England using arsenic as an element of potential concern to human health

Unusual and unexpected concentrations of a number of elements were identified in samples of house dust, that indicated the presence of mine wastes in an area where they were not expected. In pursuing this matter, several other very unusual observations and practices, involving highly contaminated mine wastes, were also identified. Here, using an available, but not a custom-made database, the matter is pursued. In England and Wales, the usual framework within which hazards are assessed, starts with an identification of those levels of exposure to elements which are considered to be safe and acceptable. At the other extreme, levels that are considered to be hazardous are identified together with procedures for dealing with them for different situations; for example, the manner in which contaminated land is to be used. The level at which an identification of sites and their use rests with the Local Authority, such as District Councils. Although new legislation is pending; at present for the non-occupationally exposed population there are no firm values to define which levels are acceptable and those that are not acceptable. One of the elements in the samples is arsenic and, because of its well-known toxicity, this element is selected to be of prime concern. However, simultaneous exposure to the general public is from a number of other elements, such as copper, lead, zinc, antimony, molybdenum, tin, selenium and mercury which are present in the mine wastes. The collective impairment to human health, if it should occur, is far too complex to evaluate, hence a need to focus attention upon arsenic which by any standard is present in some samples at very high concentrations, for example > 1000 mg/kg. Irrespective of any changes in permitted levels of exposure to the general public in the study area, together with those that are occupationally exposed, it is the past exposure that will give rise to the present patterns of morbidity and mortality. Because of a latent period between exposure and effects for the induction of cancers, of between 5 and 20 years, past exposures cannot be ignored. They need to be evaluated before changes are made in legislation. In England and Wales, concern to health is, in practice, invoked when there is clinical evidence of harm. With the exception of a few accidents in the study area of SW England, this is not identified, hence it is accepted, in practice, to conclude that no harm accrues following acute or chronic exposure to the mine wastes. There are reasons for questioning this, but if eventually supported, then the current very high costs for remediation of land may not be necessary and brown field sites can be used for a number of purposes. The primary concern is the lack of adequate scientific and clinical data, in relation to exposure to the wastes for the past 100 years or so. For many elements, compounds and substances, the general public is being made aware of potential risks to health but often the levels are extremely low. Using basic geochemical data for any area, it is possible to evaluate the expected background levels for elements. They should serve to identify levels that are acceptable, i.e. it is impractical or uneconomic to reduce them. Within the environment, simple tests are also available that can be used to rank risks to fauna and flora. There are also well-structured clinical evaluations of harm to humans available, which can also be ranked. All three need to be considered in the establishment of safe levels of exposure. It may not be practical to identify universal levels for exposure, rather each site, area or region needs to be considered separately in order to rank the potential risks. For the study area the exposures can be extremely high; compared with the general population, the number who are exposed is probably small. It is surprising that no effects upon human health have been noted.

A search for immunoreactive substance P and other neural peptides in the limb regenerate of the newt Notophthalmus viridescens

Immunochemical studies demonstrate that the undecapeptide substance P (SP) may be detected by radioimmunoassay in newt limb regenerates and that SP is localized in the blastemal epidermis by immunofluorescence and peroxidase-antiperoxidase staining. Immunoreactive SP is predominantly distributed at the periphery of epidermal cells, suggesting the presence of SP binding sites on the cell surface; the basal germinative layer of the epidermis and blastemal mesenchyme cells remain unreactive. The pattern of SP immunoreactivity in the blastema was compared with that of four other tachykinin-family peptides (eledoisin, kassinin, substance K, and neuromedin K) and with three non-tachykinin neural peptides (bombesin, neurotensin, and metenkephalin). With the exception of neurotensin, which showed weak staining in the basal layer but an absence in the peripheral layers of the epidermis, none of the peptides examined exhibited immunoreactivity in the blastema epidermis comparable to that of SP.

Regional distribution of substance P- and thyrotrophin-releasing hormone-like immunoreactivity and indoleamines in the rabbit spinal cord

The distribution of thyrotrophin-releasing hormone (TRH), substance P, and the indoleamines [5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA)] has been examined in selected regions of the thoracic and lumbar spinal cord of the rabbit using sensitive radioimmunoassays for the first two and HPLC with electrochemical detection for the indoleamines. The levels of TRH- and substance P-like immunoreactivity (TRH-I and SP-I, respectively) were greatest in the ventral and dorsal grey matter, respectively. The level of TRH-I in most thoracic regions was greater than that in equivalent lumbar regions, but the only segmental difference in SP-I was in the ventral grey matter, where the lumbar segment contained more immunoreactivity. 5-HT and 5-HIAA were more evenly distributed than either peptide and showed no segmental variation in levels in equivalent regions, but the ventral grey matter contained significantly higher levels of 5-HT and had a greater 5-HT/5-HIAA ratio than all other regions. The absolute levels and the overall distribution of SP-I, TRH-I, and indoleamines in the thoracolumbar cord of the rabbit was very similar to that previously reported in both rats and humans, and the possible functional role of the peptides and indoleamines in spinal neurones is discussed.

Substance P in primary afferent neurons of the female rat reproductive system

The amount of substance P-immunoreactivity (SP-I) was studied in the female rat reproductive organs (uterus, cervix, vagina and ovary) in the diestrous and estrous stages of the estrous cycle, after ovariectomy and on days 7, 14 and 19 of pregnancy. The concentration of SP-I (pmol X g-1 tissue) was generally highest in the vagina followed by cervix, uterus and ovary. SP-I concentrations in all reproductive organs were significantly higher following ovariectomy but significantly lower during pregnancy compared to concentrations from intact rats. There were no significant differences in the total content of SP-I per organ during the estrous cycle, after ovariectomy or during pregnancy (cervix, vagina). SP-I concentrations were markedly reduced in the reproductive organs of adult rats treated with capsaicin as neonates. This led to the conclusion that SP in reproductive organs is present in primary afferent fibers. The findings indicate that the number of SP-I containing primary afferent fibers in the female reproductive organs are stable elements neither increasing nor decreasing in response to changing hormonal levels or to the tissue growth and differentiation occurring during the estrous cycle or pregnancy.

Substance P and catecholaminergic expression in neurons of the hamster main olfactory bulb

A coordinated series of immunohistochemical and biochemical analyses have been conducted in the hamster to examine the dependence of substance P and tyrosine hydroxylase (TH) expression by second-order olfactory neurons, and the level of dopamine in the main olfactory bulb (MOB), on the integrity of carnosine- and olfactory marker protein (OMP)-containing primary afferent neurons. Substance P-like immunoreactivity (SPLI) is localized in external tufted cells and centrifugal afferents of the MOB; TH immunoreactivity has a wider distribution, in external tufted, middle tufted, periglomerular, and deep short-axon cells as well as in centrifugal afferents. To characterize the SPLI, this material was isolated by guanidine-HCl extraction and passage over a C18 SEP-PAK. The SPLI coelutes on HPLC with authentic substance P and, following oxidation, coelutes with substance P sulfoxide. It is sensitive to alpha-chymotrypsin and is resistant to trypsin. Thus, the SPLI in the MOB behaves as authentic substance P. Intranasal irrigation with 0.17 M ZnSO4 results in peripheral deafferentiation of the MOB for up to 8 months as evidenced by a persistent loss of OMP immunoreactivity and shrinkage of the olfactory nerve layer and glomeruli. By these criteria, the vomeronasal inputs to the accessory olfactory bulb are not destroyed and the spared vomeronasal receptor neurons do not innervate the vacated peripheral projection field in the MOB. The loss of peripheral inputs to the MOB is accompanied by marked and parallel reductions in the incidences of SPLI- and TH-positive second-order neurons despite an increase in the density of neuronal somata in the glomerular layer. Biochemical quantifications following peripheral deafferentation also demonstrate significant decreases of both substance P and dopamine, together with the expected decrease of carnosine. In contrast, the SPLI and the TH and serotoninlike immunoreactivities in centrifugal afferents as well as the TH immunoreactivity in deep interneurons do not appear to be reduced, and the MOB content of norepinephrine in centrifugal afferents is unaffected. These results collectively indicate that the loss of inputs from the primary olfactory receptor neurons can reduce the levels of at least two different, putatively neuroactive compounds (substance P and dopamine) in at least three classes of second-order neurons (external tufted, middle tufted, and periglomerular cells). The control of central neuron phenotype by the peripheral olfactory neurons thus appears to be a phenomenon of broad influence. It may play a role in processing chemosensory information as well as offering a system in which to study neuronal plasticit