High Concentrations Of Trace Metals Research Articles

Trees as bioindicator of heavy metal pollution in three European cities

Concentrations of four heavy metals were determined in tree leaves and bark collected from polluted and non-polluted areas of three European cities (Salzburg, Belgrade and Thessaloniki) for a comparative study. Platanus orientalis L. and Pinus nigra Arn., widespread in urban northern and southern Europe, were tested for their suitability for air quality biomonitoring. Leaves and barks were collected uniformly of an initial quantity of about 30 g of each sample. Analysis was accomplished by electrothermal atomic absorption spectrometry after total digestion. Site-dependent variations were found with the highest concentration level measured in Belgrade, followed by Thessaloniki and Salzburg. A higher accumulation of heavy metals was found in bark compared to leaves. Pine tree bark, accumulating higher concentrations of trace metals compared to plane tree bark, shows a higher efficiency as bioindicator for urban pollution. Both indicator species are suitable for comparative studies on bioindication of urban air pollution.

Temporal and spatial distribution of trace metals in sediments from the northern Yellow Sea coast, China: implications for regional anthropogenic processes

Surface sediment samples from 17 sites in the Yantai coastal area, the northern Yellow Sea, China, combined with a sediment core were employed for geochemical and chronological analyses for the purpose of characterizing the temporal and spatial distribution of trace metals in sediments and their implications for anthropogenic processes. The results indicated that the spatial distribution of trace metals (Cr, Ni, Ti, Pb, As, Zn, Mn and Cu) in surface sediments was significantly contributed by the sewage discharges along the Yantai coast, and the coastal currents played a major role for transporting the pollutants to offshore. The temporal concentrations of trace metals in the sediment core based on the chronology determined by a combination of radionuclide Cs-137 and 210 Pb activity demonstrated that trace metal concentrations increased step-wisely over the last ca. 100 years, corresponding to the intensity of anthropogenic processes in the Yantai area. The high levels of Cu and As before the late 1970s indicated the agricultural emission from the application of pesticides. While, all the high-trace metal concentrations since the early 1980s could be seen as diagnostic indictors of increasing industrialization, urbanization and sewage discharge in the Yantai area. Although the potential ecological risk evaluation of trace metals in the coastal area suggests low-potential ecological risk at present, some trace metals, such as As and Pb need particular attention due to their slight contamination.

Assessment of groundwater contamination by toxic metals in Ifo, Southwestern Nigeria

A study was carried out to assess groundwater contamination by toxic metals in Ifo community of Ogun state, Nigeria. Twenty two wells were sampled in this regard and analyzed for pH, temperature, redox potential (RP), alkalinity, salinity, toxic metals such as cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) using standard procedures. High trace metal concentrations were observed in most of the well water samples. Results showed that 50 % of the wells recorded values greater than WHO standard for Fe (0.06-0.59 mg/L), 41 % have Cd (0.000-0.010 mg/L) level higher than WHO standard while 82 % recorded high Pb (0.00-0.23 mg/L) levels greater than WHO standard in drinking water. Zinc values of the well water samples were generally low. The high values of Cd and Pb in most of the groundwater samples is harmful to human health and calls for necessary cautions by the public before consuming the water. The study therefore, recommends proper purification methods that will remove the toxic metals and further minimize their nefarious ill-effects on humans. Keywords: Groundwater, trace metals, parameters, standard, contamination.

Sources, distribution and temporal variability of trace metals in the Thames Estuary

Water and intertidal sediment samples were collected from 28 stations along the Thames Estuary, from the tidal limit to the outer estuary. Surveys were conducted in 1997, 1999 and 2001 to assess spatial distributions and short-term variability. Highest concentrations of trace metals in water coincided with high turbidity in the mid-estuarine region, although the particle-associated fraction varied from 22% (As) to 95% (Pb). Theoretical dilution line (TDL) plots showed that dissolved metals were largely derived from a combination of diffuse (sediment desorption) and localised point sources (outfalls, industry). Dissolved Cu and Zn both exceeded environmental quality standard (EQS) levels during the survey period. The majority of sediment metals showed common distributional patterns, with increasing concentrations upstream. This increase was greatest for pollutant metals: Ag, Cd, Cu, Hg, Pb and Zn. Partial extraction of sediment metals with 1 M HCl showed that >50% of Ag, Cd, Cu, Mn, Pb and Zn were potentially bioavailable and that the proportion of bioavailable sediment metals also increased upstream. The majority of sediment metal concentrations exceeded Interim Sediment Quality Guideline threshold effects levels (TELs) over much of the estuary. Sediment concentrations of Cu, Hg, Pb and Zn also exceeded probable effects levels (PELs) at many estuarine sites. Despite improvements in recent years, the Thames Estuary remains chronically contaminated with a range of metals.

Evidence for a relationship between hydrocarbon microseepage and trace metal anomalies: an implication for petroleum exploration

The paper reports the role of hydrocarbon microseepage in surface alterations of trace metal concentrations. In this study trace metal alterations were mapped that appear to be associated with hydrocarbon microseepages in the oil/gas fields of Mehsana block, North Cambay basin, India. The ranges of adsorbed soil gas concentrations of Methane, Ethane, Propane, i-Butane and n-Butane are found to vary from 1–402 ppb, 1–135 ppb, 1–70 ppb, 1–9 ppb, 1–18 ppb respectively, suggesting the presence of hydrocarbons and microseepage associated with the study area. The carbon isotopic signature of methane ranged from −29.5 to −43.0‰ (PDB) and ethane from −19.1 to −20.9‰ (PDB), indicating a thermogenic source of hydrocarbons. The absence of any significant correlation of Total Organic Carbon (TOC) and Total Inorganic Carbon (TIC) (r = 0.1 and 0.5 respectively) content with hydrocarbons in soil samples demonstrates the catagenetic origin of the desorbed gases. The Trace metal concentrations varied in the following manner: Ni: 49–155 ppm, V: 67–158 ppm, Cu: 29–82 ppm, Zn: 64–327 ppm, Ba: 241–554 ppm and Sr: 118–892 ppm. These high concentrations of trace metals which are more than their respective average concentrations generally found in soils are indicative of hydrocarbon induced alterations in the area. The low Eh values observed in anomalous hydrocarbon bearing soil samples compared to non anomalous samples in the area, could be attributed to the reducing conditions created by the hydrocarbon seepage from subsurface and might have influenced the trace metal solubilities which is reflected in their increased concentrations. Trace metal anomalies are seen haloed to adsorbed soil gas anomalies (ΣC2+) indicating that the major generative depressions of oil and /or gas fields of Sobhasan / Linch in the study area promoted vertical migration of hydrocarbon microbubbles which in turn facilitated trace metal deposition in the surface soils. By using integrated method approach, the weak signal of oil and gas reservoirs could be amplified in the frontier areas and the uncertainity of the vertical correlation of surface anomalies could be reduced.

Iron-hydroxide, iron-sulfate and hydrous-silica coatings in acid-mine tailings facilities: A comparative study of their trace-element composition

Abstract Surface alteration-layers often coat minerals in acid-mine drainage systems and the characterization of their chemical composition is required to understand the uptake or release of potentially toxic elements. Samples with micrometer-thick rock coatings were collected from bedrock in contact with three acidic tailings ponds and a small lake, all located within the Copper Cliff mine tailings disposal area in Sudbury, Ontario, Canada. Distribution and concentration of trace-metals in the rock coatings were characterized with Laser-Ablation Inductively-Coupled Plasma Mass Spectroscopy and Micro X-ray Fluorescence Spectroscopy. The rock coatings are composed of goethite, ferrihydrite, schwertmannite, jarosite and amorphous silica. The latter phase is a product of the non-stoichiometric weathering of the underlying siliceous rock. Layers within the coatings are distinguished on the basis of their atomic Fe:Si ratios: FeO x coatings have Fe:Si > 4:1, Si–FeO x coatings have Fe:Si = 4:1 to 1:1 and SiO x coatings have Si > Fe. Iron-rich coatings (FeO x ) in contact with acidic tailings ponds (pH x in contact with lake water at near neutral pH have similar trace-metal concentrations than Si–FeO x and SiO x , most likely the result of higher adsorption rates of metals at near neutral pH conditions. High trace-metal concentrations in Si–FeO x and SiO x are explained by the presence of jarosite-group minerals, which formed within Si-rich alteration layers through mixing of leached alkaline cations and trace elements from the underlying rock and Fe 3+ -sulfate solutions from the pond. Calculated enrichment factors for trace metals and metalloids in the coatings (relative to the pond) indicate that the mobility for Pb, As, Cr and Cu in the upper part of tailings ponds is commonly lower than the mobility for Zn, Mn, Co and Ni. The environmental significance of these findings is discussed in terms of the attenuation of trace metals in the coatings and the widespread occurrences of silica gels and jarosite-group minerals.

Polycyclic aromatic hydrocarbons and trace metal contamination of coastal sediment and biota from Togo

The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from <4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combustion activities. The sediments were also analyzed for major elements and a total of 15 trace metals, which were found in elevated concentrations. The calculated enrichment factor (EF) values relative to the Earth's crust show that the contamination is extremely severe for Cd (EF = 191), severe for Cr (EF = 18) and U (EF = 17.8), moderately severe for Zr (EF = 8.8), for Ni (EF = 6.8), Sr (EF = 5.9) and Ba (EF = 5.4), and moderate for V (EF = 3.6) and Zn (EF = 3.4). Sediments sampled in areas affected by the dumping of phosphorite mine tailings showed particularly high concentrations of trace metals. Overall, concentrations of both PAHs and trace metals in sediment tend to increase from the coastline to the open sea (2 km offshore). This is attributable to the increasingly finer texture of coastal sediment found offshore, which has a terrigenous origin and appears loaded with various contaminants through adsorption processes. Such high loads of trace metals were also found in the biota (fish and mussels). The ratio of measured trace metal concentrations in biota to threshold limits set by the World Health Organization herein defined as relative health factor (RHF) was high. Average RHF values in fish were highest for Se (470), As (250), Ag (97), Ni (78), Mn (63), Fe (53), Pb (36), Cd (10), and Cr (7) while lowest for Cu (0.08) and Zn (0.03). Cd and Al did not bioaccumulate in the analyzed fish species. In mussels, the RHF values were highest for Fe (9,108), As (295), Pb (276), Se (273), Mn (186), Ni (71), Ag (70), Cd (14), and Cu (4).

Trace metal enrichments in Lake Tanganyika sediments: Controls on trace metal burial in lacustrine systems

We investigate the distributions of several key diagenetic reactants (C, S, Fe) and redox-sensitive trace metals (Mo, Cd, Re, U) in sediments from Lake Tanganyika, East Africa. This study includes modern sediments from a chemocline transect, which spans oxygenated shallow waters to sulfidic conditions at depth, as well as ancient sediments from a longer core (∼2 m) taken at ∼900 m water depth. Modern sediments from depths spanning ∼70–335 m are generally characterized by increasing enrichments of C, S, Mo, Cd, and U with increasing water depth but static Fe distributions. It appears that the sedimentary enrichments of these elements are, to varying degrees, influenced by a combination of organic carbon cycling and sulfur cycling. These modern lake characteristics contrast with a period of high total organic carbon (C org), total sulfur (S Tot), and trace metal concentrations observed in the 900 m core, a period which follows the most recent deglaciation (∼18–11 ky). This interval is followed abruptly by an interval (∼11–6 ky) that is characterized by lower C, S, U, and Mo. Consistent with other work we suspect that the low concentrations of S, Mo, and U may indicate a period of intense lake mixing, during which time the lake may have been less productive and less reducing as compared to the present. An alternative, but not mutually exclusive, hypothesis is that changes in the lake’s chemical inventory, driven by significant hydrological changes, could be influencing the distribution of sedimentary trace elements through time.

Cobalt Uptake and Resistance to Trace Metals in Comamonas testosteroni Isolated From a Heavy-Metal Contaminated Site in the Zambian Copperbelt

A biogeochemical study of a polluted wetland site in Kitwe, Zambia shows high concentration of trace metals (e.g., > 25 and ≈ 2 fold higher than the Eco-toxic threshold values of copper and cobalt, respectively) with many sequestered with the sediment organic phase. Depth profiles in surface sediments suggest trace metal cycling between porewater and solid phases, including that of cobalt. This study documents a bacterium displaying resistance to, and accumulation of cobalt, and that cobalt has a positive effect on growth. The isolate was enriched from the microbial community and identified using 16S rRNA gene sequence analysis as a strain of Comamonas testosteroni (designated C. testosteroni TDKW). Improved growth of C. testosteroni TDKW was seen with the addition of up to 200 μM cobalt (optimal growth ca. 100 μM), while concentrations above 4 mM completely inhibited growth. C. testosteroni TDKW also exhibited resistance to high concentrations of iron and manganese, but showed limited resistance to copper or nickel. Further analysis revealed cellular cobalt accumulation and the presence of heavy-metal resistance genes, tentatively suggesting that this organism could contribute to in situ biological cycling of cobalt in mineral contaminated aquatic systems.

The Origin and Fate of Arsenic in Coalbed Natural Gas–Produced Water Ponds

Coalbed natural gas (CBNG)-produced water contains small amounts of trace metals that can accumulate over time in produced water retention ponds. Within the Powder River Basin (PRB) of Wyoming, high concentrations of trace metals in pond water and their effect on shallow groundwater are potential concerns. A pond with a maximum As concentration of 146 microg L(-1) was studied in detail to determine the potential for groundwater pollution and to explain the cause for the high concentration of As. Infiltration characteristics, subsurface hydrology, our fall and pond water quality, isotope signatures, and trace metal balances were examined to assess the hydrology and geochemistry of the pond. The results indicated minimum or no infiltration of pond water and no measurable contamination of the shallow groundwater. The high As concentrations in the pond were determined to be the result of semi-continuous inputs of CBNG-produced water with low As concentrations (0.20-0.48 microg L(-1)), exasperated by low pond volumes during drought conditions. Because of reduced infiltration and high evaporation rates, As became concentrated over time. Reduced infiltration was most likely caused by the high sodium concentration and high sodium adsorption ratio of the CBNG-produced water, which disrupt soil structure. The findings for the pond and the techniques used may serve as a template for future impact assessments of other CBNG-produced water ponds and are relevant for the approximately 4000 ponds currently permitted in the PRB and for future ponds. Further studies are recommended in the use of playa landforms to store marginal-quality produced water.

Arsenic and trace metals in river water and sediments from the southeast portion of the Iron Quadrangle, Brazil

The Iron Quadrangle has been one of the most important gold production regions in Brazil since the end of the seventeenth century. There, arsenic occurs in close association with sulfide-rich auriferous rocks. The most abundant sulfide minerals are pyrite and arsenopyrite, yet trace metal sulfides occur in subordinate phases as well. Historical mining activities have been responsible for the release of As and trace metals to both aquatic and terrestrial environments close to mining sites in the region. Therefore, this study was aimed to evaluate the distribution and mobility of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn in streams in the southeast portion of the Iron Quadrangle between the municipalities of Ouro Preto and Mariana, the oldest Brazilian Au mining province. Total concentrations of some trace metals and arsenic in water were determined. The four-stage sequential extraction procedure proposed by the commission of the European Communities Bureau of Reference (BCR) was used to investigate the distribution of these elements in stream sediments. Arsenic concentration in water was > 10 μg L⁻¹ (maximum limit permitted by Brazilian environmental regulations for water destined for human consumption) at all sampling sites, varying between 36.7 and 68.3 μg L⁻¹. Sequential extraction in sediments showed high concentrations of As and trace metals associated with easily mobilized fractions.

Ecotoxicological impact of highway runoff using brown trout (Salmo trutta L.) as an indicator model

The ecotoxicological impact of highway runoff on brown trout (Salmo trutta L.) was studied in an in situ experiment consisting of four 24 h simulated runoff episodes. Fish were maintained in 5 tanks and exposed to highway runoff from a sedimentation pond close to E6 outside the city of Oslo, Norway. The tanks had the following contaminant loadings during the episodes: stream water (control), pond inlet, pond outlet, pond inlet + stream water and pond outlet + stream water. Opposite to road salt and compared to earlier findings, the first two episodes had rather low concentrations of trace metals, hydrocarbons and polycyclic aromatic hydrocarbons. A heavy rainfall before episode 3 increased the concentrations of all the contaminants except road salt which was diluted. In addition, lowered oxygen levels led to hypoxic conditions. Overall the fish exposed to highway runoff had, compared to the control fish, higher concentrations of trace metals in gills and liver, increased activity of the antioxidant defense system represented by superoxide dismutase, catalase and metallothionein, problems with the regulation of plasma Cl and Na, as well as increased levels of blood glucose and pCO(2). Finally, this seemed to affect the metabolism of the fish through reduced condition factor. The observed effects were likely caused by multiple stressors and not by a single contaminant. The sedimentation pond clearly reduced the toxicity of the highway runoff. But even in the least polluted exposure tank (pond outlet + stream water) signs of physiological disturbances were evident.

Concentration of trace metals in boreholes in the Ankobra Basin, Ghan

Analysis of trace metals in groundwater from the Ankobra basin revealed high levels of iron, manganese and aluminium. Approximately 40% of boreholes had total iron concentration exceeding 1000 mg l-1 (maximum WHO permissible limit). Aluminium concentration varied from 0.1 mg l-1 to 2510 mg l-1 with a median value of 10.0 mg l-1.Approximately 20% of the boreholes had aluminium concentration exceeding the WHO maximum acceptable limit (200 mg l-1) for drinking water. Manganese concentration was in the range 6–2510 mg l-1 with a median of 356 mg l-1. Roughly 25% of the boreholes had manganese concentration higher than 500 mg l-1, which is the WHO maximum acceptable limit for drinking water. The concentration of mercury was higher than 1.0 mg l-1 (WHO maximum acceptable limit) in 60% of the boreholes during the rainy season but below detection limit in the dry season, suggesting anthropogenic origin for mercury in the groundwater. Other trace metals that occurred, but in insignificant concentration in boreholes, include lead, arsenic, nickel and selenium. Most of the boreholes with high trace metal concentrations were located in and around the Bawdie-Bogoso-Prestea area.

Integrated sediment quality assessment in Paranaguá Estuarine System, Southern Brazil

Sediment quality from Paranaguá Estuarine System (PES), a highly important port and ecological zone, was evaluated by assessing three lines of evidence: (1) sediment physical–chemical characteristics; (2) sediment toxicity (elutriates, sediment–water interface, and whole sediment); and (3) benthic community structure. Results revealed a gradient of increasing degradation of sediments (i.e. higher concentrations of trace metals, higher toxicity, and impoverishment of benthic community structure) towards inner PES. Data integration by principal component analysis (PCA) showed positive correlation between some contaminants (mainly As, Cr, Ni, and Pb) and toxicity in samples collected from stations located in upper estuary and one station placed away from contamination sources. Benthic community structure seems to be affected by both pollution and natural fine characteristics of the sediments, which reinforces the importance of a weight-of-evidence approach to evaluate sediments of PES.

Impact of Redox Cycles on Manganese, Iron, Cobalt, and Lead in Nodules

Redox processes are responsible for Fe and Mn segregation as Fe–Mn oxide coatings or nodules. These nodules are also trace element scavengers in soils. Redox processes are of particular importance in seasonally saturated soil containing naturally high concentrations of trace metals. We investigated the dynamics of Fe–Mn nodules and two associated trace elements, Co and Pb, under controlled redox conditions in a column experiment, including five columns fed with mimicked topsoil solution that was elevated in Fe and Mn. The results show that the redox conditions reached 100 mV, which was sufficient to dissolve Mn oxides and release the associated Co, while Pb was readsorbed onto nodule surfaces. The amounts of Mn and Co released into the water were small compared with the quantities stored in the nodules (&lt;0.1% of the initial stock stored in the nodules). The redox conditions were insufficient, however, to allow Fe oxide dissolution. On the contrary, 70 to 90% of the Fe entering the column was fixed onto the nodules. In terms of an environmental threat, these results showed that Pb would not be released from soil during nodule dissolution, whereas Co, which is less toxic, would be released.

Mersin Körfezi`nden Örneklenen Yüzey Suyu ve Patella Türlerindeki (Patella caerulea, Patella rustica) Cr, Cd ve Pb Düzeylerinin Belirlenmesi

Mersin Bay is under the effects of pollution, resulted from urbanization, agriculture and industrial processes. Trace metals is an important source of this pollution. The aim of this study is to determine the levels of concentrations of Cd, Pb and Cr in two Patellla species and seawater collected from Mersin Bay. Sampling ot P. caerulea, P. rustica and surface water was carried out in Kazanli, Karaduvar, Mersin Port and Mezitli region which was mainly affected from pollution. From each species, 25 individuals were collected from each sampling point. P. rustica was not observed in Kazanli and Mersin Port. The shell indices of P.0 caerudea and P. rustica was calculated as mean 1.91 and 2.36, respectively. Cr concentrations in P. caerulea collected from Kazanli and Karaduvar was higher than other sampling points. Whilst the Mersin Port was characterized by higher Cd concantrations. Kazanli was characterized by high levels of Pb concentrations. Higher trace metal concentrations were found in P. rustica collected from Karaduvar compared to Mezitli although there was no significant difference between these sampling points. When the trace metal concentration of two species were compared, it was observed that P. rustica contaminated higher amount of Cd and Cr concentrations.

Evaluation of Mitigation Methods to Manage Contaminant Transfer in Urban Watersheds

Abstract Three case studies on trace metal contamination in urban stormwater are presented from the Greater Vancouver area of British Columbia. In the first case study, the spatial and temporal variability in trace metals in sediments were determined in the completely urbanized Brunette watershed. A natural lake in the middle of the watershed acts as a sediment detention system, and an analysis of the sediment core showed the historic accumulation of metal and selective organic contaminants in sediments since the early 1800s. Suspended sediments transported during storm events showed significantly higher concentrations of trace metals than bedload sediments, and the largest proportion of the geochemically active metals was found to be associated with the organic-sulphur-based fraction. Benthic organism survival tests showed mixed results with lower survival and growth in urban sediments than in control sediments from a forested watershed. In the second case study, significant correlations were obtained between percent impervious cover and trace metal concentrations in 28 subwatersheds with various degrees of urbanization. It is shown that imperviousness combined with traffic density can significantly improve the prediction of metal contamination in highly urbanized watersheds. In the third case study five urban stormwater detention systems were examined over one year to determine how effective these systems were in removing metal contamination. The results were highly variable depending on a wide range of physical conditions, land use activities, traffic volume, and detention system designs. The range of total metal detention was between −15 to +72% for copper (Cu), lead (Pb), and zinc (Zn), while iron (Fe) and manganese (Mn) retention was generally poor. Labile Zn was more effectively retained in four of the five ponds, and a significant relationship was found between percent imperviousness, traffic volume, and Zn concentrations in water, sediment, and labile form.

Baseline Concentrations and Spatial Distribution of Trace Metals in Surface Soils of Guangdong Province, China

A total of 260 surface soil samples were collected to investigate the spatial distribution of trace metals in Guangdong province, one of the fast developing regions in China. The results show that the upper baseline concentrations of Cu, Pb, Zn, Cd, Ni, Cr, and Hg were 28.7, 57.6, 77.8, 0.13, 23.5, 87.0, and 0.15 mg kg(-1), respectively. Regional parent materials and pedogenesis are the primary factors influencing the concentrations of trace metals, and various anthropogenic activities are the second most important factors. The spatial distribution of trace metals is correlated to the geological characters with high concentrations of trace metals always located in regional fault areas, basins, and the Pearl River Delta alluvial plain and to the low concentrations associated with the other areas in Guangdong province.

Essential and non-essential trace metals in scalp hair of men chronically exposed to volcanogenic metals in the Azores, Portugal

Volcanoes produce and release large amounts of toxicants, and the concentration of metals in hair can be used as a biomarker of exposure to trace metals. In order to investigate whether humans exposed to volcanic emissions demonstrate higher concentrations of essential and non-essential trace metals, scalp hair of men (3–89 years) living in two areas of the Azores, one exposed to volcanic emissions and the other not, was sampled, and their content in Cd, Cu, Pb, Rb, Se, and Zn was quantified by using High Resolution Inductively Coupled Plasma Mass Spectrometry. In average, men exposed to volcanic emissions presented higher concentrations of Cd (96.9 ppb), Cu (16.2 ppm), Pb (3417.6 ppb), Rb (216.3 ppb), and Zn (242.8 ppm), but not Se (469.6 ppb). Also, strong and significant correlations were found between Cd–Rb and Pb–Rb in the exposed men. In conclusion, humans living chronically exposed to volcanic emissions show high concentrations of essential and non-essential trace metals in scalp hair, and is suggested that this type of exposure may be as harmful as living close to industrial facilities.

Assessing urban stormwater toxicity: methodology evolution from point observations to longitudinal profiling

The quality of aquatic habitat in a stormwater management facility located in Toronto, Ontario, was assessed by examining ecotoxicological responses of benthic invertebrates exposed to sediment and water from this system. Besides residential stormwater, the facility receives highway runoff contaminated with trace metals, polycyclic aromatic hydrocarbons (PAHs), and road salt. The combined flow passes through two extended detention ponds (in series) and a vegetated outlet channel. Toxicity of surficial sediment collected from 14 longitudinally arrayed locations was assessed based on 10 acute and chronic endpoints from laboratory tests with four benthic organisms. Greatest overall toxicity was observed in sediment from sites in the upstream pond, where mortality to amphipods and mayflies reached up to 100%. Downstream pond sediment was less toxic on average than the upstream pond sediment, but not the outlet channel sediment where untreated stormwater discharges provided additional sources of contamination. Macroinvertebrate communities in sediment cores were depauperate and dominated by oligochaetes and chironomids, with minimum densities and diversity at the deeper central pond sites. While sediment toxicity was associated with high concentrations of trace metals and high-molecular weight PAHs, benthic community impoverishment appeared related to high water column salinity.