Characterization of airborne trace metal and trace organic species from coal gasification

Fugitive emissions from a slagging fixed-bed coal-gasification pilot plant were analyzed by flameless atomic absorption spectrophotometry, gas chromatography, and mass spectrometry for trace metal and trace organic species. Analysis of the size distributions of airborne particulate matter inside the plant showed an abundance of large metal-containing particles; outdoor distributions in the vicinity of the plant resembled the indoor distributions, suggesting the importance of the gasifier in influencing ambient air quality. This conclusion was further supported by identification of similar organic compounds inside and outside the plant. Trace element enrichment factors based on the earth's crustal composition were greater than those based on the composition of the lignite used in the gasifier, showing the importance of characterizing the proper source material when inverstigating chemical fraction during aerosol formation. Enrichments in the present study were much greater than those found in previous sampling during aborted start-up and cleaning procedures, where normal operating temperatures had not yet been reached. Both studies showed evidence of enrichment factors which decreased with increasing particle size. Although much of the airborne mass was associated with large particles having low respirability, the high concentrations of some metals indoors suggests that further assessment of potential occupational exposures is warranted.     

Heavy metal bioaccumulation in different tissues of two fish species with regards to their feeding habits and trophic levels

Heavy metals residues (i.e. Cu, Zn, Mn, and Pb) were determined in seven chosen tissues of two fish species (Esox lucius and Carassius auratus) from Anzali wetland. The impact of feeding habit on metal accumulations in different tissues as well as the respective contribution of water and food to matel uptake by fishes were considered. No tendency for bioamplification was observed for the metals along the wetland trophic levels. Generally, there was no statistically significant relationship between the metal content of the tissues and the fish length for both species. In all cases, except for lead, the mean amounts of the metals in the flesh of the species were higher than those in commercially important fishes from the Caspian sea. However, they were below the recommended levels for human consumption.     

Trace metal concentrations in tissues of two tinamou species in mining areas of Bolivia and their potential as environmental sentinels

Mining has a long history in the Bolivian Andes and has left many tailing piles, from which trace metals may reach surface waters, soils, and biota. The potential of tinamous (Birds: Tinamidae) as sentinels has never been tested before, although their biological and ecological characteristics mean they could well be appropriate bioindicators. We captured 13 and nine individuals of the Ornate Tinamou (Nothoprocta ornata) from two polluted sites (P1 and P2) and 10 and five from control unpolluted sites (NP1 and NP2) and used, for comparative purposes, four specimens bred in captivity. We also captured six specimens of Darwin’s Nothura (Nothura darwinii) from the polluted site, P2. We determined the concentration of As, Cd, Pb, and Sb in feathers, liver, and kidney and conducted histological analyses of liver and kidney. For the Ornate Tinamou, a site effect was found for all trace metals in all tissues, with the highest concentrations at polluted sites. At the P2 site, no differences between the two tinamou species were detected except in some cases where Darwin’s Nothura shows near-double concentrations. In some cases, mean and/or individual values of trace metal concentrations reached toxicity levels at the polluted sites. Thesaurismosis in proximal convoluted renal tubules, probably related to Cd exposure, was observed in 30% of the samples from the P1 site. Significant correlations were observed between all tissues for all trace metals and also for all trace metals in each tissue. Because the species studied are ubiquitous and relatively abundant, we recommend monitoring programs based on feather analysis.     

Characterization of landfill leachates and studies on heavy metal removal

This study covers a thorough characterisation of landfill leachates emerging from a sanitary landfill area. The landfill leachates were obtained in the acidic stage of landfill stabilisation. Their organic content was high as reflected by the high BOD5 (5 day biological oxygen demand) and COD (chemical oxygen demand) values. They were also highly polluted in terms of the parameters TKN (total Kjeldahl nitrogen), NH4-N, alkalinity, hardness and heavy metals. Nickel was present in these wastewaters at a significant concentration. With regard to the high heavy metal content of these wastewaters, several physicochemical removal alternatives for the heavy metals Cu, Pb, Zn, Ni, Cd, Cr, Mn and Fe were tested using coagulation, flocculation, precipitation, base addition and aeration. Additionally, COD removal and ammonia stripping were examined. Co-precipitation with either alum or iron salts did not usually lead to significantly higher heavy metal removal than lime alone. The major methods leading to an effective heavy metal removal were aeration and lime addition. Nickel and cadmium seemed to be strongly complexed and were not removed by any method. Also lead removal proved to be difficult. The results are also discussed in terms of compliance with standards.     

Water-soluble species and heavy metal contamination of the petroleum refinary area,Jordan

The levels of lead, cadmium, copper, zinc, aluminum, chromium, and iron in street dust, soil, and plants in the Jordanian petroleum refinery were determined using flame and graphite-furnace atomic absorption spectrophotometry. Major cations (Li+, Na+, NH4+, K+, Mg2+, and Ca2+) and anions (F-, Cl-, NO3-, SO4(2-), and Br-) were also determined using suppression mode ion chromatography. Generally, higher levels of the heavy metals studied were found in street dust samples than in soil samples. On the other hand, except Cl-, and Li+ ions, other anions and cations showed higher concentrations in soil than in street dust samples. For plant samples, unwashed samples showed higher levels of heavy metals than their washed counterparts, indicating that dust fall is a source of heavy metal contamination.     

Synergistic effects of metal nanoparticles and a phenolic uncoupler using microdroplet-based two-dimensional approach

A droplet-based microfluidic technique for testing multiple reagent concentrations is presented. We used this experimental approach to study combined effects of gold (AuNP) and silver nanoparticles (AgNP) with the phenolic uncoupler 2,4-dinitrophenol (DNP) with respect to the growth of Escherichia coli. In order to evaluate the toxicity of binary mixtures, we first encapsulated the E. coli cells and particle mixtures inside the microdroplets using PEEK (polyetherketone) modules. Two-dimensional concentration spaces with about 500 well separated droplets were addressed. We subsequently analyzed the cell growth, the viability and the autofluorescence intensity (metabolic activity) of the bacteria with a micro-flow-through fluorometer and photometer. Dose-dependent synergistic effects were found for the binary mixture of AgNPs and DNP, which indicated a stronger interaction in the mixture than it was expected from effect summation. For the binary mixture of DNP and AuNPs in non-toxic concentrations, we found only weak synergistic effects at low DNP concentrations. Furthermore, the non-toxic tested AuNPs causes effect summation in the binary mixture with the phenolic uncoupler. In general, we demonstrated the efficiency of a droplet-based microfluidic system for fast high-throughput screenings of binary and multiple mixtures. This work also confirmed the relevance of highly resolved droplet-based assays for the miniaturization of ecotoxicological aquatic test systems.     

Characterization of lead-resistant river isolate Enterococcus faecalis and assessment of its multiple metal and antibiotic resistance

Contamination of surface waters has a direct impact on the public health of entire communities. Microorganisms inhabiting contaminated surface waters have developed mechanisms of coping with a variety of toxic metals and drugs. Investigations were carried out to isolate and identify lead-resistant bacteria from the river K?z?l?rmak along the city of K?r?kkale, Turkey. Of the 33 lead-resistant isolates, one isolate with a minimal inhibitory concentration of 1,200 mg?L^?1 was isolated and identified as Enterococcus faecalis by using biochemical tests and 16S rRNA sequencing. Lead-resistant E. faecalis isolate was found out to be resistant to other heavy metals like aluminum, lithium, barium, chromium, iron, silver, tin, nickel, zinc, and strontium and to drugs like amikacin, aztreonam, and gentamicin. E. faecalis harbored four plasmids with the molecular sizes of 1.58, 3.06, 22.76, and 28.95 kb. Plasmid profile analyses of cured derivatives revealed that the lead resistance ability of E. faecalis was still existing despite the elimination of all the plasmids. Moreover, the antibiotic resistance pattern of the cured derivatives did not demonstrate any change from the parental strain. Our findings indicated that the lead resistance genes of E. faecalis were located on the chromosomal DNA rather than the plasmid.     

Detection and extraction of endosulfan by metal nanoparticles

One of the most common pesticides in the developing world, endosulfan, can be detected in ppm levels using gold nanoparticles. Endosulfan adsorbs on the nanoparticle surface and upon interaction for a long time, the nanoparticles precipitate from the solution. Interaction with silver is weak, yet adsorption occurs leading to removal of endosulfan from the solution. A multilayer assembly of gold nanoparticles prepared on a glass substrate shows excellent spectrophotometric response suggesting potential applications.     

Characterization of soil heavy metal contamination and potential health risk in metropolitan region of northern China

Soil in metropolitan region suffers great contamination risk due to the rapid urbanization especially in developing countries. Beijing and Tianjin, together with their surrounding regions, form a mega-metropolitan region in northern China. To assess the soil environmental quality, a total of 458 surface soil samples were collected from this area. Concentrations of Cr, Cu, Pb, Zn, As, Cd, and Hg were analyzed and compared to the Chinese environmental quality standards for soil. Multivariate analysis was carried out to identify the possible sources and Geographic Information Systems techniques were applied to visualize the spatial data. It was found that the primary inputs of As were due to pedogenic sources, whereas Hg was mainly of anthropogenic source. Other elements including Cr, Cu, Pb, Zn, and Cd were from both lithogenic and anthropogenic origins. Health risk assessment based on the maximum heavy metal concentration indicated that As derived from sewage irrigation area can result in carcinogenic lifetime risk due to ingestion and/or dermal contact of soil. The potential non-carcinogenic risk for children is significant for Pb and the cumulative effect of multiple metals is of concern for children in the vicinity of mining site. The results increased our knowledge for understanding natural and anthropogenic sources as well as health risk for metals in metropolitan soil.     

Heavy metal accumulation and ecosystem engineering by two common mine site-nesting ant species: implications for pollution-level assessment and bioremediation of coal mine soil

The present study focuses on the abundance, heavy metal content, and the impact of ecosystem engineering activities of two coal mine site-inhabiting ant species, Cataglyphis longipedem and Camponotus compressus. The abundance of Ct. longipedem increased while that of C. compressus decreased, with increasing soil pollution. Correspondence analysis reveals a close association between soil heavy metal concentrations and Ct. longipedem abundance, but this association is lacking in the case of C. compressus. Cataglyphis ants which occupy stress-characterized niches appear to be pre-adapted to tolerate heavy metal pollution. Higher concentrations of Zn and Mn in Ct. longipedem may contribute to the strengthening of the cuticular structures, necessary for nest excavation in the hard, arid soil and for single load carrying. C. compressus ants appear to be pollution sensitive. Their higher Fe content may be related to metal uptake via plant-derived liquids and species-specific regulatory mechanisms. The metal pollution index and biota-to-soil accumulation factors, calculated by using the ant body metal content of the two species, indicate an overall decrease of soil heavy metal concentrations with increase of the site age, which reflects the degree of pollution related to the mine site age. The concentrations of total and available heavy metals (Fe, Zn, Mn, Pb, and Cu) were significantly lower in the ant nest debris soil as compared to the reference soil. The results of the present study highlight the role of ants as bioindicators and in bioremediation of contaminated soil.     

New approach for habitat characterization based on species lists of aquatic and semiaquatic bugs

A new approach is proposed for the environmental impact assessment of fresh waters. New indices and the cenological values of aquatic and semiaquatic bug (Hemiptera) species have been obtained through multivariate analysis based on the species list of 157 localities in Hungary. The 45 species involved in this study can be characterized by their preference for habitat types on a linear scale ranging from small, shallow waters to large, deep waters. The habitats themselves can be characterized by the added cenological values of the species found.     

Characterization of metal aerosols in PM10 from urban, industrial, and Asian Dust sources

Metallic elements (As, Be, Ca, Cd, Co, Cr, Fe, K, Mn, Ni, Pb, Sb, Se, and Zn) in PM10 aerosols were determined at urban and industrial sites, which are affected by traffic and residential sources, metallurgical activity, and petrochemical and steel works. The effect of the long-range transported Asian Dust on the metal content of aerosols was also examined. At the urban sampling site, concentrations of As, Cd, Pb, Se, and Zn were assigned to road traffic and combustion sources, Ca and Fe to soil dust sources from long-range transported Asian Dusts, and Cr and Ni to metallurgical sources transported from the nearby industrial complex, based on Principal Component Analysis (PCA). Enhanced Cr and Ni concentrations at the metallurgical industrial site suggest that local emissions from metal-assembly facilities and manufacture of alloys contributed to elevated levels of those metals. We also observed that petrochemical activities contributed to increased levels of Sb and Zn. When Asian Dust events occurred, Ca, Fe, K, and Zn concentrations dramatically increased compared to values without the Asian Dust. Two different types of Asian Dust events were observed. For the Asian Dust event 1 (4/1/2007), the Fe and K concentrations were much higher by a factor of 2–3 than those for the Asian Dust event 2 (3/2/2008), while As, Mn, and Zn concentrations were significantly higher on the Asian Dust event 2. Backward trajectory analysis showed that for the Asian Dust event 2, the air mass had passed over the heavily industrialized zones in China during long-range transport to the current sampling site, suggesting that the As, Mn, and Zn may have originated from industrial sources.     

Determination of antimicrobial and heavy metal resistance profiles of some bacteria isolated from aquatic amphibian and reptile species

The aim of the present study was to determine the level of antibiotic resistance patterns and distribution of heavy metal resistance of bacterial isolates from aquatic animals (Lissotriton vulgaris, Pelophylax ridibundus, Emys orbicularis, Mauremys rivulata, and Natrix natrix) in Turkey (Kavak Delta). A total of 153 bacteria have been successfully isolated from cloaca and oral samples of the aquatic amphibians and reptilians which were found, namely, Aeromonas sp. (n?=?29), Plesiomonas sp. (n?=?7), Vibrio sp. (n?=?12), Citrobacter sp. (n?=?12), Enterobacter sp. (n?=?11), Escherichia sp. (n?=?22), Klebsiella sp. (n?=?22), Edwardsiella sp. (n?=?6), Hafnia sp. (n?=?1), Proteus sp. (n?=?19), Providencia sp. (n?=?8), and Pseudomonas sp. (n?=?4). In terms of antibiotic and heavy metal susceptibility testing, each isolate was tested against 12 antibiotics and 4 metals. There was a high incidence of resistance to cefoxitin (46.40 %), ampicillin (44.44 %), erythromycin (35.29 %), and a low incidence of resistance to gentamicin (6.53 %), kanamycin (8.49 %), chloramphenicol (9.15 %), and cefotaxime (10.45 %). The multiple antibiotic resistance index of each bacterial species indicated that bacteria from raised amphibians and reptiles have been exposed to tested antibiotics, with results ranging from 0 to 0.58. Most isolates showed tolerance to different concentrations of heavy metals, and minimal inhibition concentrations ranged from100 to >3,200 μg/mL. According to these results, a significant occurrence of bacteria in the internal organs of reptiles and amphibians, with a high incidence of resistance against antibiotics and heavy metals, may risk aquatic animals and the public health. These data appoint the importance of epidemiological surveillance and microbiological monitoring and reinforce the need to implement environment protection programs for amphibian and reptile species.     

Characterization of particulate matter and its related metal toxicity in an urban location in South West India

This study reports the quantification of the toxicity of particulate matter (PM)-bound metals and their possible associated risks to human health. For assessment of PM, 24-h samples of PM₁₀ and PM_2.5 were collected by Mini Vol-TAS sampler at an urban site of Pune. Samples were sequentially extracted with ultrapure water and concentrated HNO₃ and analyzed for “soluble” and “total” metals. Factor analysis identified the resuspension of road dust due to traffic, biomass burning, construction activities, and wind-blown dust as possible sources that played an important role for overall pollution throughout the year. Water-soluble proportion was found to be ≤20 % for Cr, Co, Fe, and Al; ≥50 % for Sr, Cd, Ca, and Zn; and a substantial proportion (～25–45 %) for Mn, Ba, K, Na, Ni, Mg, Cu, and Pb metals in PM₁₀. For PM_2.5, the water-soluble proportion was ≤20 % for Fe, Co, Ni, Cr, and Al, while Sr, K, and Cd were mostly soluble (>50 %) and Cu, Ba, Mn, Ca, Zn, Pb, Na, and Mg were substantially soluble (～25–45 %). In the present study, among the toxic metals, Cd and Pb show higher concentration in the soluble fraction and thus represent the higher bioavailability index and especially are harmful to the environment and exposed person. Risk calculations with a simple exposure assessment method showed that the cancer risks of the bioavailable fractions of Cr, Cd and Ni were greater than the standard goal.     

Water quality assessment by means of HFNI valvometry and high-frequency data modeling

The high-frequency measurements of valve activity in bivalves (e.g., valvometry) over a long period of time and in various environmental conditions allow a very accurate study of their behaviors as well as a global analysis of possible perturbations due to the environment. Valvometry uses the bivalve's ability to close its shell when exposed to a contaminant or other abnormal environmental conditions as an alarm to indicate possible perturbations in the environment. The modeling of such high-frequency serial valvometry data is statistically challenging, and here, a nonparametric approach based on kernel estimation is proposed. This method has the advantage of summarizing complex data into a simple density profile obtained from each animal at every 24-h period to ultimately make inference about time effect and external conditions on this profile. The statistical properties of the estimator are presented. Through an application to a sample of 16 oysters living in the Bay of Arcachon (France), we demonstrate that this method can be used to first estimate the normal biological rhythms of permanently immersed oysters and second to detect perturbations of these rhythms due to changes in their environment. We anticipate that this approach could have an important contribution to the survey of aquatic systems.     

An approach to partition the anthropogenic and natural components of heavy metal accumulations in roadside agricultural soil

This paper describes a new approach that allows us to partition the anthropogenic and natural contributions to heavy metal accumulations in roadside agricultural soils. This approach, combining trend analysis and multivariate statistical analysis, partitions total heavy metals into three components: anthropogenic, natural, and unexplained residual. The approach was applied in a case study in Yixing City, China, to determine the spatial distributions of heavy metal accumulations. The results show that anthropogenic components of Pb, Cu, Zn, and Cd account for 52.4%, 23.04%, 5.09%, and 10.9% of total content, respectively. Spatial distributions of anthropogenic components are characterized by decreasing accumulation with increasing distance from the road. Ranges of influence of traffic for Pb, Cu, and Cd are beyond 300 m, whereas the range of Zn is less than 200 m. The spatial distributions of the four elements?? natural components show relatively similar distribution patterns. Assessments of variable partition methods show that the predicted values of Pb, Cu, Zn, and Cd are consistent with their measured values. The anthropogenic components extracted from total contents of heavy metal will be useful for modeling heavy metal accumulations produced by human activities.