Copper Smelter Emissions Research Articles

Long-term Dynamics of Small Mammal Communities in the Period of Reduction of Copper Smelter Emissions: 2. β-Diversity

Long-term Dynamics of Small Mammal Communities in the Period of Reduction of Copper Smelter Emissions: 2. β-Diversity

Long-term Dynamics of Small Mammal Communities in the Period of Reduction of Copper Smelter Emissions: 1. Composition, Abundance, and Diversity

The long-term dynamics of the composition, total abundance, and diversity (α- and γ-diversity) of small mammal (SM) communities is analyzed in the vicinity of a large copper smelter during the periods of high (1990–1997), reduced (1998–2009), and almost terminated emissions (2010–2019). It is shown that the response of SM communities to pollution has not fundamentally changed over 30 observation years. An increase in pollution caused a significant reduction in the total abundance and α-diversity of communities and their dominance index in each of the three periods; at the same time, the γ-diversity remained similar in the background (13 species) and polluted zones (12 species). The reduction of emissions had no significant influence on the SM communities in the background (conditionally clean) zone: the species structure fluctuated insignificantly, the dominance structure did not change, and the increase in the animal abundance by the end of observations (owing to forest voles but not insectivores) was due to successional changes in the vegetation. The reduction of emissions led to a succession of dominants near the smelter and the trends of changes in abundance in this area differed from those observed in the buffer and impact zones (increase and no change, respectively). The increase in the abundance of species of different trophic groups (phytophages, granivores, and zoophages) in the moderately polluted (buffer) zone can be considered a symptom of the initial stages of recovery due to the improvement of habitat quality. Positive shifts in the SM community from the highly polluted (impact) zone are less distinct, being expressed only as an increase in the proportion of shrews.

Vulnerability to Copper Smelter Emissions in Species of the Herb–Dwarf Shrub Layer: Role of Differences in the Type of Diaspore Dispersal

The type of diaspore dispersal may have a significant effect on the vulnerability of herbaceous plants to anthropogenic transformation of ecosystems. However, there is still no unified opinion on the relationship between the type of diaspore dispersal and the processes of extinction and colonization. Here, descriptions of vegetation performed in the zone of impact from the Middle Ural Copper Smelter in the periods of high and low emission levels (1995–1998 and 2014–2016, respectively) have been analyzed to test two hypotheses: (1) the type of diaspore dispersal has an effect on plant vulnerability, with the species whose diaspores are dispersed farther being less vulnerable to habitat transformation; and (2) irrespective of the type of dispersal, recolonization is less intense under high than under low pollution levels. It has been found that the species richness of all plant groups highly varies in space: it decreases sharply in the zone of heavy toxic loads, but localities with high species richness occur even under conditions of heavy pollution. With the increasing pollution level, the species diversity within plant groups on a mesoscale (hundreds of meters) decreases more strongly than that on a macroscale (kilometers). Species with different types of diaspore dispersal differ from each other both in sensitivity to pollution and in the capacity for recolonization after reduction of emissions, but the relationship between vulnerability and the distance of diaspore dispersal is ambiguous. High sensitivity to pollution and low recolonization capacity have been revealed in species characterized by either the lowest (autochores) or the highest dispersal distance (epi- and endozoochores), with anemochores being the least vulnerable. The diversity of most groups in the zone of heavy pollution has remained low over the past 20 years; some positive shifts have occurred in myrmecochores and typical anemochores, with the dynamics of the latter being independent of pollution level.

Assessment of elemental composition and properties of copper smelter-affected dust and its nano- and micron size fractions

A comprehensive approach has been developed to the assessment of composition and properties of atmospherically deposited dust in the area affected by a copper smelter. The approach is based on the analysis of initial dust samples, dynamic leaching of water soluble fractions in a rotating coiled column (RCC) followed by the determination of recovered elements and characterization of size, morphology and elemental composition of nano-, submicron, and micron par ticles of dust separated using field-flow fractionation in a RCC. Three separated size fractions of dust (<0.2, 0.2-2, and >2 μm) were characterized by static light scattering and scanning electron microscopy, whereupon the fractions were analyzed by ICP-AES and ICP-MS (after digestion). It has been evaluated that toxic elements, which are characteristics for copper smelter emissions (As, Cu, Zn), are accumulated in fraction >2 μm. At the same time, up to 2.4, 3.1, 8.2, 6.7 g/kg of As, Cu, Zn, Pb, correspondently, were found in nanoparticles (<0.2 μm). It has been also shown that some trace elements (Sn, Sb, Ag, Bi, and Tl) are accumulated in fraction <0.2, and their content in this fraction may be one order of magnitude higher than that in the fraction >2 μm, or the bulk sample. It may be assumed that Sn, Sb, Ag, Bi, Tl compounds are adsorbed onto the finest dust particles as compared to As, Cu, Zn compounds, which are directly emitted from the copper smelter as microparticles.

The Effect of a Copper Smelter Emissions on the Stock and Decomposition of Coarse Woody Debris in Spruce and Fir Woodlands

We have studied the share of coarse woody debris (CWD) reserves at different decay classes in the spruce and fir woodland within the impact area of aerial pollution from the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast). Control and impact areas slightly differ in total reserves and number of trunks of CWD (sum of standing and fallen dead wood). However, the number of CWD tends to grow in proximity to the plant. The mechanisms involved in CWD-reserve formation differ between impact and control sites. A larger number of relatively thin trunks prevail in CWD reserves of impact sites when compared to the lower number of thick trunks at control sites. The CWD share of 30% in the total number of dead and living trees did not differ across pollution loads. However, the share of CWD reserves in total stock is 1.9 times higher near the plant than at the control site. The share of logs at the initial stages of decomposition (first and second decay classes) is 3.2 times higher in terms of CWD number and 4.2 times higher in terms of CWD reserves than at the control sites. This points to the strong inhibition of CWD decomposition. The pattern of decay classes of all sizes of fallen trees significantly differs in volume across pollution zones.

Assessment of elemental composition and properties of copper smelter-affected dust and its nano- and micron size fractions.

A comprehensive approach has been developed to the assessment of composition and properties of atmospherically deposited dust in the area affected by a copper smelter. The approach is based on the analysis of initial dust samples, dynamic leaching of water soluble fractions in a rotating coiled column (RCC) followed by the determination of recovered elements and characterization of size, morphology and elemental composition of nano-, submicron, and micron particles of dust separated using field-flow fractionation in a RCC. Three separated size fractions of dust (<0.2, 0.2-2, and >2μm) were characterized by static light scattering and scanning electron microscopy, whereupon the fractions were analyzed by ICP-AES and ICP-MS (after digestion). It has been evaluated that toxic elements, which are characteristics for copper smelter emissions (As, Cu, Zn), are accumulated in fraction >2μm. At the same time, up to 2.4, 3.1, 8.2, 6.7g/kg of As, Cu, Zn, Pb, correspondently, were found in nanoparticles (<0.2μm). It has been also shown that some trace elements (Sn, Sb, Ag, Bi, and Tl) are accumulated in fraction <0.2, and their content in this fraction may be one order of magnitude higher than that in the fraction >2μm, or the bulk sample. It may be assumed that Sn, Sb, Ag, Bi, Tl compounds are adsorbed onto the finest dust particles as compared to As, Cu, Zn compounds, which are directly emitted from the copper smelter as microparticles.

Genetic variation and selfing rate in Lychnis flos-cuculi along an industrial pollution gradient.

We studied nine populations of a meadow mixed-mating plant Lychnis flos-cuculi growing in a gradient of copper smelter emissions. We hypothesize that metal tolerant populations in the polluted areas have experienced a loss of genetic variation and are more selfing than the populations from the unpolluted areas. One hundred and thirty-five parental plants and 1059 offspring were genotyped with six microsatellite markers. Selfing rates were assessed manually, with Rmes, Mltr and Colony2. Soil toxicity, population density and pollinators' activity were estimated in the studied areas. Populations from the heavily polluted area have experienced a strong founder effect. However, at present, they are characterized by high densities. A recent genetic explosion was registered for the population from the most polluted site, probably due to forest thinning under pollution effects. Selfing rates estimated with different approaches agreed well only for populations with high genetic variation; they comprised 0-0.23 and were similar between polluted and clean areas. Self-fertilization in L. flos-cuculi hardly represents a mechanism for the fixation of advantageous alleles and a barrier for gene flow from non-tolerant populations. The employment of different methods of selfing rate estimation in populations with low genetic variation appears to be necessary, though not a guarantee of reliable conclusions.

Interspecific differences in determinants of plant distribution in industrially polluted areas: Endogenous spatial autocorrelation vs. environmental parameters

Interspecific differences have been clearly shown in the contribution of endogenous spatial autocorrelation (caused by dispersal) to the spatial structure of undisturbed vegetation. However, this phenomenon has not been studied in industrially polluted areas, where heavy metals’ excess is traditionally considered to be the main driver of ecosystem processes. We compare the contributions of endogenous autocorrelation and environmental parameters to the distribution of herbaceous plants in open and forested sites heavily polluted with copper smelter emissions. Principal coordinates of neighbour matrices were used to create spatial predictors that were incorporated into beta regression models together with environmental predictors. Their importance for species’ spatial structure was assessed using multimodel inference and variation partitioning approach. Equisetum sylvaticum, Leucanthemum vulgare, Tussilago farfara, Carex rostrata, Scirpus sylvaticus and Deschampsia cespitosa responded strongly to soil toxicity, while Agrostis capillaris and Lychnis flos-cuculi, to microtopography and tree disposition. Endogenous autocorrelation was strongly pronounced in L. flos-cuculi distribution across all study sites and was substantial for A. capillaris in open areas. Despite the extreme level of soil toxicity, the importance of other environmental parameters and endogenous autocorrelation remarkably differed among species, resulting from interspecific differences in ecological preferences and dispersal mode.

Diversity and Spatial Structure of Soil Fungi and Arbuscular Mycorrhizal Fungi in Forest Litter Contaminated with Copper Smelter Emissions

The diversity and spatial structure of soil fungi (SF) and arbuscular mycorrhizal fungi (AMF) communities in the southern taiga forest litter were studied in sites with two contrasting contamination levels with copper smelter emissions. The operational taxonomic unit richness and evenness in the communities of both target groups decreased under contamination. The community structure of contaminated and control areas differed for SF, whereas they were similar for AMF. According to spatial structure analysis results on a scale of tens of meters, a gradual change of composition with distance was revealed for the SF community within 30-m intervals in the control sites. No spatial autocorrelation was found for AMF in the control sites. However, pronounced patchiness was characteristic of both SF and AMF communities within 10 m of contaminated sites. In the contaminated area, no specific spatial structure determinants of the studied communities was found among environmental factors such as water content, heavy metal concentrations in the forest litter, sample plot localization relative to canopy density, and herb vegetation diversity and abundance. However, in the control sites, AMF richness depended on herb abundance and litter chemistry.

СТРУКТУРА ОТПАДА ЕЛОВО-ПИХТОВЫХ ДРЕВОСТОЕВ В УСЛОВИЯХ ЗАГРЯЗНЕНИЯ ВЫБРОСАМИ СРЕДНЕУРАЛЬСКОГО МЕДЕПЛАВИЛЬНОГО ЗАВОДА

СТРУКТУРА ОТПАДА ЕЛОВО-ПИХТОВЫХ ДРЕВОСТОЕВ В УСЛОВИЯХ ЗАГРЯЗНЕНИЯ ВЫБРОСАМИ СРЕДНЕУРАЛЬСКОГО МЕДЕПЛАВИЛЬНОГО ЗАВОДА

The total content of nitrogen in leaves and wood of trees growing in the area affected by the Głogów Copper Smelter

Soils affected by industrial emissions of a copper smelter may contain high amounts of heavy metals. Heavy metal infiltration across the soil is a potential source of groundwater contamination. Simultaneously, many ions, especially Cu2+ and Pb2+, can be accumulated by plants growing within the emission range. The aim of this study was to determine the influence of high Cu and Pb soil contamination on the total nitrogen content in leaves and wood of trees growing in an area exposed to copper smelter emissions. Samples of leaves and wood of Populus robusta L. and Betula pendula L. as well as soil samples were taken from an area affected by industrial emissions, namely from the former sanitary zone of the Glogow Copper Smelter. The samples were collected in 2010. The particle size distribution, pH, organic carbon, total nitrogen and the total content of Cu and Pb in the soil samples were determined. In the plant samples (foliage and trunks), the total nitrogen was assayed. The results were analysed statistically. The following conclusions were drawn: the litter horizon of soils affected by industrial emissions contains high level of heavy metals (3450-5400 mg Cu kg -1 , 1020-1500 mg Pb kg -1 ), exceeding threshold values for industrial areas. Also the humic horizon is characterised by an increased Cu and Pb content: 174-1530 mg Cu kg-1 and 268-702 mg Pb kg-1. The leaves of the tested species contained more nitrogen than the wood, although the birch wood contained more nitrogen then the poplar. There was no difference in the nitrogen content of the annual tree rings of both species. Despite high levels of copper and lead in the tested soils, there was no effect of this factor on the nitrogen content of the leaves, bark and wood of the studied trees.

Long-term dynamic of forest vegetation after reduction of copper smelter emissions

The state of tree and ground vegetation layers in spruce-fir forests around the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast) has been repeatedly evaluated in 25 permanent sampling plots at 5- to 10-year intervals (1989–2013). The results have been used to characterize the dynamics of plant communities in the period of reduction of emissions from the smelter. Although the annual amount of emissions has decreased from 150–225 × 103 t in the 1980s to less than 5 × 103 t after 2010, the vegetation in the impact zone (1 and 2 km from the smelter) remains severely suppressed: the trees continue to die off, and the diversity of ground vegetation layer is very low. In zones with low and moderate levels of industrial pollution (30 and 4–7 km from the smelter), natural factors associated with windfall disturbance after the 1995 windstorm with snow have played a more important role in the dynamics of forest communities than the reduction of emissions itself.

Change in biogenic accumulative elementary pedogenic processes in zones with a different level of pollution by copper smelter emissions

It is shown that litter formation, humification, and the humus state of soils in zones at different distances from a smelter are determined by biotic and abiotic components of the ecological conditions of pedogenesis.

Mortality from Copper Smelter Emissions Circa 1967

Pope et al. (2007) found lowered monthly mortality rates during a 1967–1968 copper smelter strike, coincident with and attributed to widespread reduced airborne sulfate levels. The authors cited three “intervention” studies associating particulate emissions reductions with mortality reductions as supportive. Evidence below suggests that mortality reductions in the study by Pope et al. and “interventions” are likely linked to reductions in particulate matter (PM) types known to be harmful: high levels of biologically active metals and partially burned carbon. The first “intervention” study (Pope et al. 1992), examined PM–mortality associations over 4 years, encompassing closure of a Utah steel mill (sulfate not measured; sulfur dioxide levels were “low”). Mortality rates were 40% greater than expected when the mill was operating, suggesting toxicity of mill emissions. Strongest associations were with respiratory disease, then cardiovascular disease. Filter extracts when the mill was operating contained high levels of lead, copper, and zinc and were more toxic (Frampton et al. 1999). Mattson and Guidotti (1980) found women living in communities near copper smelters (1968–1975) in Arizona experienced highly elevated relative risks (RRs) for acute respiratory disease mortality: averaged RR for all six mining towns (40,000 combined population) was 5.61. Later, Small et al. (1981) found levels of arsenic, Cu, and Zn elevated by factors up to 100,000 in Arizona smelter plumes. Lead levels in plumes were comparable with those of other metals. Thus, Pb, Cu, and Zn levels were elevated when either the steel mill or copper smelters were operating, and acute mortality (especially respiratory) was elevated simultaneously. Mortality associations with blood Pb have recently been found at low levels of Pb (Menke et al. 2006). Blood Pb has a half-life of about 1 month, reflecting current exposure; associations may indicate both chronic and acute effects (Schober et al. 2006)—relevant information for copper smelter emissions. The second “intervention” study (Hedley et al. 2002) found mortality rate reductions following a mandated 1990 reduction of sulfur in residual oil and diesel fuels in Hong Kong. Later, Hedley et al. (2006) found that ambient vanadium and nickel were reduced up to 90%, concomitantly with reductions of sulfur in residual oil. Mortality or inflammatory associations with ambient residual oil emissions but not secondary sulfate were previously found (Grahame and Hidy 2004; Janssen et al. 2002; Maciejczyk and Chen 2005). The third “intervention” (Clancy et al. 2002) found that mortality rates declined after uncontrolled domestic burning of coal was banned in Dublin, Ireland. Wintertime black smoke levels declined from 80 μg/m3 before the ban to 20 μg/m3 afterward; sulfate was not measured. Given the toxicology of partly burned hydrocarbons, mortality reduction would be expected. The three “supporting” studies do not provide evidence that widespread secondary sulfate reductions were related to mortality reductions during the interventions. Rather, high levels of specific metals, or of black smoke, appear to have health relevance. Toxicology suggests secondary sulfates per se are unlikely to be harmful at ambient levels (Schlesinger and Cassee 2003). Resolving this inconsistency requires researching mechanisms by which secondary sulfate or precursors are necessary to create a toxic mixture at ambient levels; for example, how much do which metals increase in solubility due to such processes, and how much harm occurs that would not otherwise occur? Either soluble or insoluble metals common to steel mills and copper smelter emissions can be harmful at high doses (Ghio et al. 1999). Research suggestions are available (Grahame and Schlesinger (2007).

Mortality from Copper Smelter Emissions: Pope Responds

Grahame’s thoughtful and well-documented letter addresses one of the most important issues regarding our analysis of the mortality effects of a copper smelter strike in the U.S. Southwest (Pope et al. 2007). Grahame’s basic contentions are that changes in exposure to secondary sulfate alone were not sufficient to explain the observed mortality effects, and that the mortality effects were more likely due to changes in exposure to co-pollutants, such as biologically active metals and black smoke. My coauthors and I agree with Grahame regarding several points. As he argues in his letter and as we briefly discussed in our article, the copper smelter strike also resulted in changes in exposure to metals and other co-pollutants. There is certainly evidence that metals, black carbon, and other by-products of incomplete combustion and high temperature industrial processes contribute to the pollution’s toxicity—as part of the complex mixture of fine particles. We respectfully disagree in part with Grahame regarding the lack of evidence implicating secondary sulfate particles as contributing to adverse health effects. He asserts that the three “supporting” intervention studies “do not provide evidence that widespread secondary sulfate reductions were related to mortality reductions during the interventions.” However, in addition to changes in metals, black smoke, and other co-pollutants, one thing that all three intervention studies had in common was substantive changes in exposure to sulfate particles. In Utah Valley (Pope et al. 1992), the steel mill (largely from its coke ovens) was responsible for over 75% of the valley’s total sulfur oxide emissions. During winter-time temperature inversions, high concentrations of fine particulate matter with a relatively high proportion of sulfates occurred. The closure of the steel mill resulted in a disproportionately large drop in exposure to both metals, sulfates, and other mill-related pollutants. Mortality reductions in Hong Kong were also associated with reductions in sulfur oxide exposure (Hedley et al. 2002). In Dublin, although sulfates were not measured, the banning of bituminous coal certainly resulted in an abrupt reduction in particulate pollution—including sulfate particles (Clancy et al. 2002). In addition to the intervention studies discussed above, there is ample epidemiologic evidence that sulfate pollution, as part of complex mixtures, contributes to adverse health effects. For example, the Harvard Six-Cities Study (Dockery et al. 1993) and the American Cancer Society prospective cohort studies (Pope et al. 2002) of long-term air pollution exposure found both fine particulates and sulfate particles to be associated with mortality risk. A workshop of several research teams on source apportionment of particulate matter health effects found that the sulfate-related component of fine particles was most consistently associated with daily mortality (Thurston et al. 2005). The relative toxicity of sulfates per se and the additive or synergistic effects of related co-pollutants remains a matter of study and debate (Chen et al. 2006; Grahame and Schlesinger 2007). Nevertheless, epidemiologic studies of the adverse health effects of air pollution (Pope and Dockery 2006) have implicated fine particulate pollution from at least three general sources: coal combustion, high-temperature industrial processes, and traffic sources. Overall, the literature suggests that sulfates—as part of mixtures of fine particles that include metals, black carbon, and other by-products of coal combustion, high-temperature industrial processes, and vehicle emissions—can contribute to adverse health effects. We reaffirm our conclusion that the results of our analysis of the mortality effects of the copper smelter strike “contribute to the growing body of evidence that ambient sulfate particulate matter and related air pollutants are adversely associated with human health.”

Quantifying the Components of Biocomplexity Along Ecological Perturbation Gradients

The study of ecological perturbation gradients provides a unique opportunity to investigate the utility of various biocomplexity indices. The ability of four measures of biocomplexity (quadratic entropy, taxonomic entropy, total complexity and total diversity) and their components to quantify the nature and degree of perturbation in plant communities was assessed by how closely each measure reflected the trends in biocomplexity that are expected to occur along a gradient of decreasing perturbation. The measures were applied to two landscapes, located near Sudbury, Canada and Harjavalta, Finland, perturbed by nickel–copper smelter emissions. Taxonomic entropy was determined to be the most useful of the four measures as it has a clear information-theoretical meaning, the relative contributions of classical diversity and taxonomic information can be easily isolated, and its computation is straightforward relative to the other measures. Additionally, it is relatively insensitive to community evenness, thereby rendering it less sample-size dependant and a more appropriate measure to use for comparisons between studies as well as for conservation and restoration purposes.

Arsenate Adsorption Structures on Aluminum Oxide and Phyllosilicate Mineral Surfaces in Smelter-Impacted Soils

A clearer understanding of arsenic (As) retention and transport in forest soils impacted by copper smelter emissions may reduce risks to human health and provide insight into As behavior in the vadose zone. On Vashon-Maury Island in Puget Sound, As is predominantly associated with the fine (< 63 microm) fraction of surficial soils. X-ray diffraction of oriented samples from the < 2 microm size fraction indicate that clinochlore isthe dominant phyllosilicate. X-ray absorption spectroscopy (XAS) was employed to examine As oxidation state and local coordination environment in impacted soil samples. Arsenic is present as As(V) in tetrahedral coordination with oxygen, associated with aluminum (Al) octahedra in bidentate binuclear (bridging) structures with As-Al distances of 3.15 - 3.16 angstroms. Including multiple scattering (MS) paths derived from the arsenate tetrahedron in esperanzaite significantly improved the match between XAS fine structure (EXAFS) data and models generated from theoretical phase and amplitude functions. The data are interpreted to indicate arsenate adsorption onto poorly crystalline aluminum oxyhydroxides and/or the edges of clinochlore interlayer hydroxyl sheets with constrained geometries causing MS to be important This implies that As initially released from the smelter as particulate As(III) and As(V) oxides was oxidized, dissolved, and adsorbed onto soil minerals and colloids; no evidence for relic arsenic oxide was observed. Physical transport of arsenic oxide particles and As adsorbed on soil colloids may account for limited downward migration of As within the soil column. The oxidizing and mildly acidic pH conditions in the upper vadose zone promote stable sorption complexes; barring substantial changes in soil chemistry, As is not expected to experience significant mobilization.

Metal species distribution in top- and sub-soil in an area affected by copper smelter emissions

The major objective of this study was to investigate the chemical forms in which selected metals occur in soils polluted with metallurgical dusts as well as to estimate potential mobility and bioavailability of these metals. Six soil profiles situated at different distances from Cu smelters were chosen and soil samples were taken from top- and sub-surface layers. The soils differed in their textures but all of them showed high contents of sand fraction and were neutral or slightly alkaline in reaction, due to liming. Ale research involved the analysis of the total contents of 8 metals (Al, Fe, Mu, Zn, Cr, Ni, Cu and Pb) and their speciation according to the Zeien and Bruemmer method. Total concentrations of metals varied in the following ranges (mg/kg): Al, 1420–11,400; Fe, 1710–19,700; Mn, 55–470; Zn, 6.4–153; Cr, 2.15–16.9; Ni, 1.18–13.8; Cu, 7.4–1710; Pb, 11–460. The metal fractions determined were: mobile, exchangeable, occluded in MnO x , organically bound, occluded in amorphous and crystalline FeO x and residual. The metals' behaviour in soils depended both on the soil properties and the metals' origin. Typically lithogenic metals (Al, Fe, Cr, Ni) occured in the soils predominantly in stable fractions (bound to FeO x and silicates), whereas metals of anthropogenic origin (Cu, Pb) showed considerably higher percentages of mobile and exchangeable fractions, which together made up 17.0–59.7% of Cu and 2.5–38.8% of Pb. The highest contributions of those fractions occured in the top layers of sandy soils. Therefore, it is concluded that anthropogenic metals are likely to be leached from the polluted soils, especially the sandy ones.

Distribution of copper smelter emissions in Southeastern Arizona ? Using honey mesquite as a bioindicator

Honey mesquite (Prosopis juliflora), a representative species of the Sonoran Desert ecosystem, was studied as a possible bioindicator for industrial smelter pollution. Samples from soils, leaves and bark were collected along distance and elevation gradients from the largest operating copper smelter in Arizona and analyzed for element concentrations of Zn, Cu, Fe, Ti, Mn, Al, Mg, Cs, Sm, Ce, U, Th, Yb, As, La, Hf, Sb, Sc, V, In, W, Ba, Br, K, Na, Cl and Au. Depending on the sample type — soil, leaf or bark — between 5 and 15 elements were identified as smelter immissions. Two distinct covariate element groups formed in samples from the study site could be related to the chemistry of different smelting processes. A common atmospheric transport pattern was found to exist for the smelter emittants Cu, Sb and As over long distances. The identification and specification of smelter immissions in honey mesquite makes this tree a well-suited bioindicator for industrial smelter pollution.

A principal component analysis of sulfur concentrations in the western United States

Data from a 40 site network of air samplers in the western United States were used in a principal components analysis to obtain spatial patterns of the inter-site correlations of sulfur concentrations. After rotation of the initial eigenvectors, two large regions were identified which accounted for 33.1% of the variance in the data. Three other smaller regions were identified which also had significant variance. The first eigenvector included all sites in the southern part of the network and was attributed to copper smelter emissions in Arizona and New Mexico. The second eigenvector included sites in the northern great plains and was attributed to episodic incursions of sulfur from the east. The third, fourth and fifth eigenvectors were attributed to locally important conditions.