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Responses of terrestrial arthropods to air pollution: a meta-analysis
2010
Zvereva, Elena L. | Kozlov, Mikhail V.
Background, aim, and scope Arthropods, with over a million species described, are ubiquitous throughout different environments. Knowledge of their responses to human impact is crucial for understanding and predicting changes in ecosystem structure and functions. Our aim was to investigate the general patterns and to identify sources of variation in changes of the diversity, abundance and fitness of terrestrial arthropods (including Arachnida, Collembola and Insecta) in habitats affected by point polluters. Main features We found 134 suitable studies which were published between 1965 and 2007. These data came from impact zones of 74 polluters in 20 countries with the largest representation from Russia (28 polluters), Poland (12 polluters) and the USA (six polluters). The database allowed calculation of 448 effect sizes (i.e. relative differences between measurements taken from polluted and control sites) on the effects of various point polluters like non-ferrous industries, aluminium plants, cement, magnezite, fertilising and chemical plants, power plants, iron- and steel-producing factories. We used meta-analysis to search for general effects and to compare between polluter types and arthropod groups, and linear regression to describe the latitudinal gradient and to quantify relationships between pollution and arthropod responses. Results The overall effect of pollution on arthropod diversity did not differ from zero. However, species richness of soil arthropods (both living on the soil surface and within the soil) tended to decrease, and species richness of herbivores to increase, near point polluters. Abundance of terrestrial arthropods near point polluters decreased in general. This decrease resulted from strong adverse effects on soil arthropods, especially on decomposers and predators. Densities of herbivores increased, but a number of research biases that we discovered in published data may have led to overestimation of the latter effect. The dome-shaped density pattern along pollution gradients was discovered only in 5% of data sets. Among herbivores, only free-living defoliators and sap-feeders demonstrated higher densities in polluted sites; the effects of pollution on other guilds were not significant. Near the polluters, conifers suffered higher increase in damage from herbivores than deciduous woody plants and herbs. Overall effect of pollution on arthropod performance was negative; in particular, individuals from polluted sites were generally smaller than individuals from control sites. This negative effect weakened with increase in duration of the pollution impact, hinting evolution of pollution resistance in populations inhabiting polluted sites. Stepwise regression analysis demonstrated that pollution-induced changes in both the density and performance of arthropods depended on climate of the locality. Negative effects on soil fauna increased with increase in annual precipitation; positive effects on herbivore population density increased with increases in both mean July temperature and annual precipitation. Discussion We detected effects of research methodology on the outcome of published studies. Many of them suffer from research bias—the tendency to collect data on organisms or under conditions in which one has an expectation of detecting significant effects. Pseudoreplicated studies (one polluted site contrasted to one control site) frequently reported larger effects than replicated studies (several polluted sites contrasted with several control sites). These methodological flaws especially influenced herbivory studies; we conclude that increase in herbivory in both heavily and moderately polluted habitats is not as frequent as it was earlier suggested. In contrast, the decrease in abundance of predators is likely to be a widespread phenomenon. Thus, our analysis supports the hypothesis that pollution may favour herbivore populations by creating an enemy-free space. Consistent declines in abundance of soil arthropods in impact zones of different polluters suggest that this group can potentially be used in bioindication of pollution-induced changes in terrestrial ecosystems. Conclusions Main effects of pollution on arthropod communities (decreased abundance of decomposers and predators and increased herbivory) may have negative consequences for structure and services of entire ecosystems. Responses of arthropods to pollution depend on both temperature and precipitation in such a way that ecosystem-wide adverse effects are likely to increase under predicted climate change. Recommendations and perspectives Our analysis confirmed that local severe impacts of industrial enterprises on biota are well-suited to reveal the direction and magnitude of the biotic effects of aerial pollution, as well as to explore the sources of variation in responses of organisms and communities. Although we analysed the effects of point polluters, our conclusions can be applied to predict consequences of pollution impacts on regional and even global scales. We argue that possible interactions between pollution and climate should be accounted for in the analyses of global change impacts on biota.
اظهر المزيد [+] اقل [-]Application of preparative capillary gas chromatography (pcGC), automated structure generation and mutagenicity prediction to improve effect-directed analysis of genotoxicants in a contaminated groundwater
2010
Meinert, Cornelia | Schymanski, Emma | Küster, Eberhard | Kühne, Ralph | Schüürmann, Gerrit | Brack, Werner
Background, aim and scope The importance of groundwater for human life cannot be overemphasised. Besides fulfilling essential ecological functions, it is a major source of drinking water. However, in the industrial area of Bitterfeld, it is contaminated with a multitude of harmful chemicals, including genotoxicants. Therefore, recently developed methodologies including preparative capillary gas chromatography (pcGC), MOLGEN-MS structure generation and mutagenicity prediction were applied within effect-directed analysis (EDA) to reduce sample complexity and to identify candidate mutagens in the samples. A major focus was put on the added value of these tools compared to conventional EDA combining reversed-phase liquid chromatography (RP-LC) followed by GC/MS analysis and MS library search. Materials and methods We combined genotoxicity testing with umuC and RP-LC with pcGC fractionation to isolate genotoxic compounds from a contaminated groundwater sample. Spectral library information from the NIST05 database was combined with a computer-based structure generation tool called MOLGEN-MS for structure elucidation of unknowns. Finally, we applied a computer model for mutagenicity prediction (ChemProp) to identify candidate mutagens and genotoxicants. Results and discussion A total of 62 components were tentatively identified in genotoxic fractions. Ten of these components were predicted to be potentially mutagenic, whilst 2,4,6-trichlorophenol, 2,4-dichloro-6-methylphenol and 4-chlorobenzoic acid were confirmed as genotoxicants. Conclusions and perspectives The results suggest pcGC as a high-resolution fractionation tool and MOLGEN-MS to improve structure elucidation, whilst mutagenicity prediction failed in our study to predict identified genotoxicants. Genotoxicity, mutagenicity and carcinogenicity caused by chemicals are complex processes, and prediction from chemical structure still appears to be quite difficult. Progress in this field would significantly support EDA and risk assessment of environmental mixtures.
اظهر المزيد [+] اقل [-]Biochemical biomarkers in environmental studies—lessons learnt from enzymes catalase, glutathione S-transferase and cholinesterase in two crustacean species
2010
Jemec, Anita | Drobne, Damjana | Tišler, Tatjana | Sepčić, Kristina
Background, aim and scope For reliable environmental risk assessment of pollutants, knowledge on the effects at different levels of biological organisation is needed. During the early days of biomarker research in environmental studies approximately two decades ago, biochemical biomarkers were considered as the most promising tool for such purposes. Among these, three enzymes have often been studied: catalase (CAT), glutathione S-transferase (GST) and cholinesterase (ChE). However, despite their intensive research, their measurements in invertebrates have not been commonly applied in environmental risk assessment (ERA) or for regulatory purposes. Main features In the present review, we summarise our past experiences in biochemical biomarker research in two crustacean species: water flea Daphnia magna and terrestrial isopod Porcellio scaber. This is to orientate their use and to provide recommendations for the use of novel biomarkers in environmental studies, such as proteomic or genomic responses. Results and discussion We assessed the intrinsic properties of biochemical biomarkers CAT, GST and ChE in the D. magna and the isopod P. scaber. It was found that they are not in agreement with the expectations that were previously given for their use in environmental studies. To advance their use in environmental risk assessment, we suggest that based on their properties, their role should be more specifically defined. ERA includes several distinct steps, among them hazard identification, effect assessment and finally risk characterisation, each of which requires a different type of toxicity data. We recommend that the use of biochemical markers is most appropriate for hazard identification because this is a procedure whose purpose is to characterise the potential hazard of the substance in question and is more flexible in terms of using different tools. Furthermore, our results imply that biochemical markers are not always more sensitive than whole-organism responses, as was anticipated. Their sensitivity depends on the mode of action, duration of exposure and test species. Therefore, we suggest that combining both a battery of biomarkers from different levels of biological organisation and an array of biomarkers within a single level could identify hazard adequately. Conclusions The lesson learnt from biochemical biomarkers in environmental studies utilizing crustacean model species is that, for successful application of each group of biomarkers, their intrinsic properties are needed to be known before an (eco)toxicity study is designed. We suggest that a substantial body of experience obtained with biochemical biomarkers should be exploited to new emerging biomarkers in environmental studies in order to facilitate their application. Recommendations and perspectives The future of biomarkers lies in a combination of traditional biochemical and new-generation biomarkers. The latter are not only a potential replacement for existing biomarkers but will also provide new knowledge which might encourage renewed research and development of traditional biomarkers. For research purposes, complete ecotoxicity information should include contributions from molecular fingerprint of an organism, as well as whole organism, population and ecosystem responses. Still, the type of biomarkers used for routine purposes will depend on their reproducibility, their ease of use, robustness, affordability of the methodology and the type of chemicals, organisms and ecosystem of interest.
اظهر المزيد [+] اقل [-]Influence of temperature and origin of dissolved organic matter on the partitioning behavior of polycyclic aromatic hydrocarbons
2010
Haftka, Joris J. H | Govers, Harrie A. J | Parsons, John R
Background, aim, and scope The behavior of polycyclic aromatic hydrocarbons (PAHs) is affected by dissolved organic matter (DOM) present in pore water of soils and sediments. Since partitioning to DOM reduces the bioavailable or freely dissolved PAH concentration in pore water, it is important to assess the effect of environmental variables on the magnitude of dissolved organic matter to water partition coefficients (K DOC). The objective of this study was to apply passive samplers to measure freely dissolved PAHs allowing depletion from the aqueous phase. The method was applied to determine K DOC at different temperatures for a selection of PAHs with natural DOM of very different origin. Materials and methods Freely dissolved concentrations of (spiked) phenanthrene, anthracene, fluoranthene, pyrene, and benzo[e]pyrene were determined by exposing polydimethylsiloxane (PDMS) fibers to aqueous solutions containing DOM extracted from freshwater sediments from Finland and the Netherlands. The K DOC values were subsequently calculated at different temperatures (3.2, 20, and 36°C) by including temperature-dependent PDMS to water partition coefficients (K PDMS) in a mass balance. Furthermore, the effect of temperature on partitioning of PAHs to PDMS fibers or DOM was assessed by comparing the enthalpy of sorption to the excess enthalpy of dissolution of liquid PAHs. Results and discussion Partitioning to DOM resulted in a decrease of freely dissolved concentrations with increasing DOM concentrations and a large range in log K DOC values at 20°C for benzo[e]pyrene was observed (log K DOC = 4.93-6.60 L kg⁻¹ organic carbon). An increase of 10°C in temperature resulted in a decrease of K PDMS by 0.09 to 0.13 log units for phenanthrene to pyrene and a decrease of K DOC by 0.13 log units for pyrene. The calculated enthalpies of sorption were less exothermic than the (negative) excess enthalpies of dissolution as expected for non-specific interactions between PAHs and PDMS or DOM. Conclusions The bioavailability of PAHs in sedimentary pore waters can be accurately determined by application of PDMS fibers (without requiring negligible depletion) in the presence of natural DOM with different sorption affinity for PAHs. The observed natural variability in log K DOC values for different sediments shows that large differences can occur in freely dissolved PAH concentrations in pore water and properties of DOM should be taken into account in predicting the bioavailability of PAHs. Furthermore, the effect of temperature on the partitioning behavior of PAHs shows that interactions between PAHs and environmental sorbents are comparable to interactions between PAHs in their pure condensed liquid phase and calculated excess enthalpies can be safely used to directly correct partition coefficients for temperature. Recommendations and perspectives The application of PDMS fibers in measuring freely dissolved PAH concentrations can be used to study structural and thermodynamic aspects of PAH sorption to natural DOM as well as other environmental processes such as enhanced diffusion phenomena in pore water that are dependent on the amount (or concentration) of DOM, sorption affinity of DOM, and hydrophobicity of PAHs. These environmental factors will therefore give further insight into the site-specific exposure to freely dissolved PAH concentrations in soil and sedimentary pore water.
اظهر المزيد [+] اقل [-]Evaluation of surface water quality using an ecotoxicological approach: a case study of the Alqueva Reservoir (Portugal)
2010
Palma, Patricia | Alvarenga, Paula | Palma, Vera | Matos, Cláudia | Fernandes, Rosa Maria | Soares, Amadeu | Barbosa, Isabel Rita
Background, aim, and scope Freshwater reservoirs can be impacted by several hazardous substances through inputs from agricultural activity, sewage discharges, and groundwater leaching and runoff. The water quality assessment is very important for implementation of the monitoring and remediation programs to minimize the risk promoted by hazardous substances in aquatic ecosystems. Evaluation of the degree of contamination of aquatic environments must not take in account only its chemical characterization but it must be complemented with biological assays, which determine potential toxic effects and allows an integrated evaluation of its effects in populations and aquatic ecosystem communities. The application of this type of strategy has clear advantages allowing a general evaluation of the effects from all the water components, including those due to unknown substances and synergic, antagonistic, or additive effects. There are only a few studies that reported ecotoxicological acute end points, for the assessment of surface water quality, and the relationship among toxicity results and the anthropogenic pollution sources and the seasonal period. The aim of this study was to assess the ecotoxicological characterization of the surface water from Alqueva reservoir (South of Portugal) and to evaluate the influence of anthropogenic sources of pollution and their seasonal variation in its toxicity. The construction of Alqueva reservoir was recently finished (2002) and, to our knowledge, an ecotoxicological assessment of its surface water has not been performed. Because of that, no information is available on the possible impact of pollutants on the biota. The surface water toxicity was assessed using acute and chronic bioassays. The results are to be used for developing a monitoring program, including biological methods. Materials and methods Water samples were collected during 2006-2007, at each of the nine sampling sites selected in Alqueva reservoir. These sampling points allow an assessment at the upstream (Sra. Ajuda, Alcarrache, Álamos-Captação), at the middle (Alqueva-Montante, Alqueva-Mourão, Lucefecit), and at the downstream of the water line (Alqueva-Jusante; Ardila-confluência; Moinho das Barcas). The campaigns occurred in February, March, May, July, September, and November of 2006 and February, March, and May of 2007. The rainy season comprised November, February, and March, and the dry season included May, July, and September. A total of 81 samples were collected during the study period. The physical-chemical parameters were analyzed following standard and recommended methods of analysis (APHA et al. 1998). The pesticide analyses were performed using gas chromatography according to DIN EN ISO 6468 (1996). Surface water ecotoxicity was evaluated using the following bioassays: Vibrio fischeri luminescence inhibition, Thamnocephalus platyurus mortality, and Daphnia magna immobilization and reproduction assay. The Spearman rank correlation coefficients were used to evaluate the associations between the water sample physicochemical properties (from each sampling station in each season) and the acute and chronic toxicological effects, with a level of significance p < 0.05. Results In the acute toxicity study, the species that was found to be the most sensitive was T. platyurus. T. platyurus detected a higher number of toxic water samples during the dry season. Concerning the luminescent inhibition of V. fischeri, the results showed that this organism detected a great number of toxic water samples in rainy seasons. The water samples, which promoted higher toxic effects towards this species, were from the north and from the middle of the reservoir. The correlation analysis showed that V. fischeri luminescent inhibition (%) was positively correlated with total phosphorus, chlorpyrifos, iron, and arsenic. T. platyurus mortality (%) was positively correlated with the water pH, 5-day biochemical oxygen demand (BOD₅), chlorides, atrazine, simazine, terbuthylazine, and endosulfan sulfate contents. Although the surface waters did not promote acute toxicity to the crustacean D. magna, in the chronic exposure, a significant decrease in the number of juveniles per female was observed, mainly at the dry period. The number of juveniles per female, in the reproduction test of D. magna, was negatively correlated with pH, temperature, BOD₅, chloride, atrazine, simazine, terbuthylazine, and endosulfan sulfate. The water toxicity of the Alqueva water might be due principally to the intensive agriculture activities surrounding the reservoir and to the municipal wastewater discharges. Discussion The physicochemical parameters and the pesticide concentrations indicated that the water quality was worse in the north part of the reservoir system. These results are characteristic of the majority of reservoirs, once the construction of the dam promoted, by itself, the impounding of water flow and the increase of compound residence time. The toxicity tests corroborate with the chemical characterization. Acute toxicity of Alqueva water may be a result of the effect promoted by chlorpyrifos, endosulfan sulfate, phosphorus, and iron. Chronic toxicity may be a result of the effect of herbicides, arsenic, organic matter, endosulfan sulfate in mixture. Hence, the water toxicity of the Alqueva might be due principally to the intensive agriculture activities surrounding the reservoir and to the municipal wastewater discharges. Conclusions This study has shown that a large number of samples from different sites of the Alqueva reservoir contained potentially toxic contaminants. The sites with impaired water quality were those located at the north of the reservoir and in the surrounding areas of intensive agricultural activity. The results demonstrated that the use of a screening of acute and chronic toxicity tests with organisms from different trophic levels and with distinct sensibilities allowed the detections of several patterns of toxicity from spatial and temporal variability promoted by natural or anthropogenic sources. The chronic responses showed, especially in the dry season, that some of the species belonging to this aquatic ecosystem might be at risk. Recommendations and perspectives The V. fischeri and T. platyurus are two species that should be used in the acute bioassays for the ecotoxicological monitoring programs of this reservoir. It is recommended that other species, such as a productive organism (algae), be included in the next study, once the water reservoir had high levels of herbicides. Ecotoxicological assessment of surface water must integrate initial screening based on acute tests followed always by chronic bioassays. The results implicitly suggest that the implementation of processes of remediation by reducing pollutant input into the reservoir and by the implementation of water treatment processes is important and necessary.
اظهر المزيد [+] اقل [-]Isotope ratios of lead in Japanese women's hair of the twentieth century
2010
Matsumoto, Megumi | Yoshinaga, Jun
Introduction Isotope ratios of lead (²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb) in Japanese women's hair of the twentieth century were measured to evaluate lead contamination of human proximate environment of those days. Materials and Methods The historic hair samples (n = 40) were collected in 1980s by staffs of Department of Human Ecology, University of Tokyo, from Japanese women who cut their hair in 1910s to 1968 by themselves for hair piece or needle pad and who had stored it by the time of collection. Additional five contemporary hair samples (one from male and four from females) were also included. The hair samples were digested with HNO₃, diluted with water to Pb concentration of 10 µg/kg, and isotope ratios were measured by inductively coupled plasma mass spectrometry. Results and Discussion Isotope ratios as well as Pb concentration in the hair samples of the twentieth century varied to a considerable extent depending on the period of hair cut. The oldest hair samples (1910-1920s) had the highest concentration and the most distinct isotope ratios from those of Japanese domestic Pb indicating serious contamination of proximate environment of people of those days with Pb originated from mines in other regions of the world, probably through the usage of Pb-containing face powder. The concentration and isotope ratios of Pb decreased thereafter indicating less serious contamination of proximate environment of Japanese which, in turn, should have affected by environmental contamination of mid-twentieth century due to industrial activities and leaded gasoline. Contemporary Pb level was quite low (<1 mg/kg); however, isotope ratios were close to those in 1960s when hair concentration was assumed to be strongly affected by leaded gasoline.
اظهر المزيد [+] اقل [-]Modification of exopolysaccharide composition and production by three cyanobacterial isolates under salt stress
2010
Ozturk, Sahlan | Aslim, Belma
Background, aim, and scope Polysaccharides are renewable resources representing an important class of polymeric materials of biotechnological interest, offering a wide variety of potentially useful products to mankind. Exopolysaccharides (EPSs) of microbial origin with a novel functionality, reproducible physico-chemical properties, stable cost and supply, became a better alternative to polysaccharides of algal origin. EPSs are believed to protect bacterial cells from desiccation, heavy metals or other environmental stresses, including hostimmune responses, and to produce biofilms, thus enhancing the cells chances of colonising special ecological niches. One of the most important stress factor is salt stress for microorganisms. The present investigation is aimed to determine correlation between salt resistance and EPS production by three cyanobacterial isolates (Synechocystis sp. BASO444, Synechocystis sp. BASO507 and Synechocystis sp. BASO511). It is also aimed to investigate the effect of salt concentrations on EPS production by cyanobacteria and effect of salt on monosaccharide composition of EPS. Materials and methods Cyanobacterial isolates were identified by 16 S rRNA analysis. Its salt (NaCl) tolerance and association with exopolysaccharides (EPSs) production in three cyanobacterial isolates were investigated. Also, EPS was analysed by HPLC for monomer characterization. Results Increased EPS production was associated with NaCl tolerance. The most tolerant isolate, Synechocystis sp. BASO444, secreted the most EPS (500 mg/L). EPS production by Synechocystis sp. BASO444, Synechocystis sp. BASO507 and Synechocystis sp. BASO511 was investigated following exposure to 0.2 and 0.4 M NaCl. Also, flasks containing medium without NaCl were inoculated in the same manner to serve as controls. The monosaccharide compositions of EPS produced by the three isolates following exposure to 0.2 M NaCl were analysed by HPLC. Control EPS of BASO444 was composed of glucose (97%) and galacturonic acid (3%). The composition of BASO511 (control) was glucose (95%), xylose (4.80%), arabinose (0.13%), glucuronic acid (0.03%) and galacturonic acid (0.04%). However, the composition of BASO507 (control) was glucose (0.98%), xylose (98.00%), arabinose (1.00%), glucuronic acid (0.01%) and galacturonic acid (0.01%). In the presence of 0.2 M NaCl, EPS compositions and ratios of three cyanobacterial isolates changed. Discussion Although hyperproduction of EPS in response to starvation, antiviral activity, thickening agent and cosmetic industry for product formulations has been reported for cyanobacteria, the effect of NaCl on EPS production in cyanobacteria is not a popular area of study. There are no clear reports correlating EPS production and NaCl tolerance. The gap in the data about the effect of NaCl on cyanobacterial EPS production was filled by this investigation, and the results of our study have important implications in both the industrial and environmental arenas. Conclusions Our results indicate that 1) exposure to elevated concentrations of NaCl affects the composition of EPS produced by Synechocystis sp. BASO444, Synechocystis sp. BASO507 and Synechocystis sp. BASO511, and 2) there is a correlation between NaCl tolerance and EPS production in some cyanobacteria. Recommendations and perspectives Differences in the monosaccharide composition and ratios of EPS may promote NaCl tolerance in these microorganisms. As well, these alternative composition polysaccharides may be important for industrial applications.
اظهر المزيد [+] اقل [-]Interaction of nano-TiO₂ with lysozyme: insights into the enzyme toxicity of nanosized particles
2010
Xu, Zhen | Liu, Xi-Wei | Ma, Yinsheng | Gao, Hong-Wen
Background, aim, and scope Nanomaterials have been used increasingly in industrial production and daily life, but their human exposure may cause health risks. The interactions of nanomaterial with functional biomolecules are often applied as a precondition for its cytotoxicity and organ toxicity where various proteins have been investigated in the past years. In the present study, nano-TiO₂ was selected as the representative of nanomaterials and lysozyme as a representative for enzymes. By investigating their interaction by various instrumentations, the objective is to identify the action sites and types, estimate the effect on the enzyme structure and activity, and reveal the toxicity mechanism of nanomaterial. Materials and methods Laboratory-scale experiments were carried out to investigate the interactions of nano-TiO₂ with lysozyme. The interaction of nano-TiO₂ particles with lysozyme has been studied in the analogous physiological media in detail by UV spectrometry, fluorophotometry, circular dichroism (CD), scanning electron microscope, ζ-potential, and laser particle size. Results The interaction accorded with the Langmuir isothermal adsorption and the saturation number of lysozyme is determined to be 580 per nano-TiO₂ particle (60 nm of size) with 4.7 × 10⁶ M⁻¹ of the stability constant in the physiological media. The acidity and ion strength of the media obviously affected the binding of lysozyme. The warping and deformation of the lysozyme bridging were demonstrated by the conversion of its spatial structure from α-helix into a β-sheet, measured by CD. In the presence of nano-TiO₂, the bacteriolysis activity of lysozyme was subjected to an obvious inhibition. Discussion The two-step binding model of lysozyme was proposed, in which lysozyme was adsorbed on nano-TiO₂ particle surface by electrostatic interaction and then the hydrogen bond (N-H···O and O-H···O) formed between nano-TiO₂ particle and polar side groups of lysozyme. The adsorption of lysozyme obeyed the Langmuir isothermal model. The binding of lysozyme is dependent on the acidity and ion strength of the media. The bigger TiO₂ aggregate was formed in the presence of lysozyme where lysozyme may bridge between nano-TiO₂ particles. The coexistence of nano-TiO₂ particles resulted in the transition of lysozyme conformation from an α-helix into a β-sheet and a substantial inactivation of lysozyme. The β-sheet can induce the formation of amyloid fibrils, a process which plays a major role in pathology. Conclusions Lysozyme was adsorbed on the nano-TiO₂ particle surface via electrostatic attraction and hydrogen bonds, and they also bridged among global nano-TiO₂ particles to form the colloidal particles. As a reasonable deduction of this study, nano-TiO₂ might have some toxic impacts on biomolecules. Our data suggest that careful attention be paid to the interaction of protein and nanomaterials. This could contribute to nanomaterial toxicity assessment. Recommendations and perspectives Our results strongly suggest that nano-TiO₂ has an obvious impact on biomolecules. Our data suggest that more attention should be paid to the potential toxicity of nano-TiO₂ on biomolecules. Further research into the toxicity of nanosized particles needs to be carried out prior to their cell toxicity and tissue toxicity. These investigations might serve as the basis for determining the toxicity and application of nanomaterials.
اظهر المزيد [+] اقل [-]Recent trends of the emission characteristics from the road construction industry
2010
Chauhan, Sippy K | Sharma, Sangita | Shukla, Anuradha | Gangopadhyay, S
Bitumen is a black, thermoplastic, hydrocarbon material derived from the processing of crude oil. At ambient temperature, bitumen is solid and does not present any health/environmental risks. This is one of the main reasons that bitumen is widely used for road construction all over the world. But during manufacturing/modification according to its application, storage, transportation, and use of bitumen is heated giving off various hydrocarbons emissions. In recent years, there has been increasing interest in investigating the potential of bitumen emissions to cause health effects. This is mainly because of the reason that bitumen has small amount of poly-aromatic hydrocarbons, along with some other volatiles like benzene, toluene, etc., which are known to be carcinogenic in nature. Thus, assessment of the emission characteristics and health hazards of bitumen fumes may have far reaching industrial economic and public health implications. In this review, we will discuss about the emission characteristics from bitumen, asphalts, or road construction, which is mainly contributed by bitumen fumes. Sampling strategies and analytical methods employed are also described briefly.
اظهر المزيد [+] اقل [-]Elevated blood lead levels and cytogenetic markers in buccal epithelial cells of painters in India
2010
Khan, Mohd Imran | Aḥmad, Iqbāl | Mahdi, Abbas Ali | Akhtar, Mohd Javed | Islām, Najmul | Ashquin, Mohd | Venkatesh, Thuppil
Background, aim, and scope Lead, a major contaminant, is highly used in paint manufacturing due to its anticorrosive properties. Recent reports indicated high lead content among Indian paints used for commercial purposes. Painters are continuously exposed to these lead containing paints during painting of both commercial as well as residential buildings. Lead is well-known for its genotoxicty in occupational workers; however, in Indian painters the genotoxic effects of lead have not been reported to date. Therefore we aimed to study the genotoxic end points in painters due to their long-term exposure to these high lead-containing Indian paints. Materials and methods Study group selection was made after a questionnaire administration, which included questions about lifestyle and medical history to exclude exposure to the other potential sources of genotoxics. Blood and buccal cell samples were obtained from 30 male painters and from a similar number of age-matched controls of same location with no occupational exposure to lead. Blood lead levels (Pb-B) were measured in painters and controls. Micronucleus (MN) frequencies and nuclear changes, i.e., karyorrhexis, karyolysis, broken egg, and binucleated, were investigated in buccal epithelial cells. Results Painters had significantly (P < 0.01) greater lead levels in blood than the control group. MN frequencies and nuclear changes in buccal epithelial cells were also significantly (P < 0.01) elevated in painters as compared with control subjects. Regression analysis also revealed significant (P < 0.01) association of Pb-B with all the genotoxic endpoints in painters. Cytogenetic damage was significantly associated with Pb-B as no other co-founding factors (smoking, alcohols) showed significant difference between both groups. Discussion Lead is widely used in paints which may serve as potential source of exposure among painters due to their long-term engagement with paints. Our results clearly demonstrated genotoxicity among the exposed population as evident from increase micronucleus frequencies, frequent nuclear changes, and apoptosis. Many studies had previously related nuclear change events in buccal epithelial cells with the progression of different carcinomas. Furthermore in-depth investigations with larger sample size are needed to provide evidence to this effect. Conclusions Here, we report cytogenetic toxicity to the exposed population by the high lead containing paints from India for the first time. Frequent, high and unregulated use of lead in paints may cause genetic mutation and may accelerate cytogenetic damage which may further lead to different carcinomas in painters. These findings need to be considered and necessary steps should be taken to protect the occupational workers engaged with these high lead-containing paints. Recommendations The use of lead in paints is completely unregulated in India and routine surveillance of paints for lead content is still lacking. These paints are readily available in markets and are also used in other products (jewelry, miniblinds) which could be exported to other countries including United States and Europe. Serious consideration should be given to the inclusion of regulations and bans on the use of lead in paints. Moreover, attention should also be paid towards the use of various protective measures (face-masks, hand gloves, and separate clothes) by the workers as safe work practices during working periods.
اظهر المزيد [+] اقل [-]