Refine search
Results 1301-1310 of 1,546
Volatile organic compounds and bioaerosols in the vicinity of a municipal waste organic fraction treatment plant. Human health risks Full text
2012
Vilavert, Lolita | Nadal, Martí | Figueras, María J. | Domingo, José L.
PURPOSE: The aim of this study was to analyze air concentrations of chemical and microbiological pollutants in the vicinity of an organic waste treatment plant, Ecoparc-2, located in Montcada i Reixac (Catalonia, Spain), as well as to determine the seasonal trends. The human health risks due to the presence of those agents were also assessed. METHODS: Air samples were collected at different distances and wind directions from the Ecoparc-2 in two campaigns (winter and summer of 2010). The levels of 19 volatile organic compounds (VOCs) were analyzed by GC-MS or HPLC-UV. In turn, the airborne amount of total bacteria, gram-negative bacteria, and fungi (including Aspergillus fumigatus) was also determined. RESULTS: Mean VOC concentrations were found to be 32.4 and 15.7 μg/m3 in winter and summer, respectively. Fungi at 25°C presented the highest geometric mean (1,126 and 863 cfu/m3 in winter and summer, respectively), while the concentrations of fungi at 37°C and total bacteria were also important in the hot season (332 and 250 cfu/m3, respectively). These results are in agreement with data obtained from the scientific literature. Anyhow, no significant differences were observed between both campaigns including those related to distances and wind directions. The current pollutant levels in the surrounding environment were also various orders of magnitude lower than those recently observed inside the facility. CONCLUSIONS: The human exposure to VOCs near the Ecoparc-2 was estimated to be low. Furthermore, the current environmental concentrations of those chemical and microbiological agents were clearly below threshold values recommended by regulatory organizations.
Show more [+] Less [-]Oxidative transformation of carbamazepine by manganese oxides Full text
2012
He, Yan | Xu, Jian | Zhang, Yuan | Guo, Changsheng | Li, Lei | Wang, Yuqiu
This study presents oxidative transformation of carbamazepine by synthetic manganese oxide (δ-MnO2) as well as impact of variables including initial MnO2 loading, pH, coexisting metal ions, and humic acid (HA) on transformation. Manganese oxide (δ-MnO2) was synthesized and stored in the form of suspension. The oxidative reactions were conducted in 50 mL polyethylene (PE) centrifuge tubes with constant pH maintained by buffers. The kinetic experiment was carried out in the solution of pH 2.72 containing 5.0 mg/L of carbamazepine and 130.5 mg/L of MnO2. Effects of initial MnO2 loading (0–130.5 mg/L), pH (2.72–8.58) and 0.01 M of coexisting solutes (metal ions and HA) on carbamazepine oxidation were also determined. Reaction kinetics indicated that carbamazepine was rapidly degraded in the first 5 min, and approximately 95 % of carbamazepine was eliminated within 60 min. The reaction exhibited pronounced pH dependence and increased with decreasing pH values. The transformation of carbamazepine was also accelerated with increasing MnO2 loadings. Coexisting metal ions competed with carbamazepine for reactive sites leading to reduced carbamazepine removal, and the inhibitive capacity followed the order of Mn2+ > Fe3+ > Ca2+ ≈ Mg2+. Presence of HA in aqueous solution caused a significant reduction on the magnitude of carbamazepine transformation. This study indicated that carbamazepine can be effectively degraded by δ-MnO2, and transformation efficiency was strongly dependent on reaction conditions. It suggests that amendment of soil with MnO2 be a potential alternative to solve carbamazepine pollution.
Show more [+] Less [-]Daily, seasonal and monthly variations in ozone levels recorded at the Turia river basin in Valencia (Eastern Spain) Full text
2012
Castell-Balaguer, Nuria | Téllez, Laura | Mantilla, Enrique
INTRODUCTION: The Turia river basin, located in the east of the Iberian Peninsula, drains into the Mediterranean Sea near the city of Valencia (population, 814,208). The predominance of sea-breeze fluxes favours the inland transport of pollutants from the city up the basin where ozone concentrations exceeding the threshold for protection of human health are systematically recorded during the summer months. METHODS: This work analyses the variability in ozone levels by examining their spatial and temporal distribution in a Mediterranean river basin downwind from a city within the period 2005–2008. Orographic determinants and atmospheric fluxes induce strong variations in ozone measurements, even on relatively close locations. CONCLUSIONS: Results show a different behaviour of the monthly means and the daily cycles depending on the season of the year and the measuring environment, with summer/winter ratios ranging from 2.4 in cities to 1.6 inland, and mean values always higher in the interior of the basin. Daily cycles show significant summer/winter differences related to the predominant situations of anticyclonic stability in winter, which limit ventilation, and the predominant breeze circulations in summer. Results also show a “weekend effect” at urban and medium-distance stations. At the most inland station, the weekend/weekday behaviour differs according to the season of the year; weekend ozone levels are higher in spring, autumn and winter, and lower in summer, coinciding with the predominance of local wind cycles that favour air mass penetration inland from the coast.
Show more [+] Less [-]Enhancement of natural radioactivity in fertilized soil of Faisalabad, Pakistan Full text
2012
Ak̲h̲tar, Nasīm | Sabiha-Javied, | Tufail, M.
BACKGROUND, GOAL, AND SCOPE: Natural radioactivity in phosphate rock (PR) is transferred to phosphate fertilizer (PF) during the manufacturing process of the PF. The continuous addition of the PF to the cultivated soil accumulates the radionuclides in the land and increases the level of radioactivity in the soil. The purpose of the present study was to investigate the enhanced level of accumulated radioactivity due to the continuous addition of the PF in the farmlands of Nuclear Institute of Agriculture and Biology (NIAB) at Faisalabad in Pakistan. The selected study area consisted of the highly fertilized farmlands and an unfertilized barren land of the NIAB. INTRODUCTION: The understudy area is very fertile for the growth of various types of crops; therefore, four agricultural research institutes have been established at Faisalabad and NIAB is one of those. The NIAB has developed various research farmlands at different places in Pakistan. The crop yield has been increased by adding various fertilizers in the farmlands. The addition of the PF accompanied with the radionuclides enhances radioactivity in the fields. Human being is exposed directly or indirectly to this radiological hazard. A prolong exposure may become a cause of health risk. MATERIALS AND METHODS: The area of study consisted of three types of lands: the land under cultivation for the last 40 and 30 years called Site 1 and Site 2, respectively, and the barren land was called Site 3. A total of 75 soil samples were collected within the crop rooting zone (up to 25 cm deep) of the soil of the NIAB farms. The samples were dried, pulverized to powder, sealed in plastic containers, and stored to achieve equilibrium between 226Ra and 222Rn. Activity concentrations of the radionuclides 238U (226Ra), 232Th, and 40K in soil samples were determined by using a high resolution gamma ray spectrometry system, consisting of an high purity germanium detector coupled through a spectroscopy amplifier with a PC based MCA installed with Geni-2000 software. RESULTS: The measured activity concentration levels of 40K were 662 ± 15, 615 ± 17, and 458 ± 20 Bq kg−1, 226Ra were 48 ± 6, 43 ± 5, and 26 ± 4 Bq kg−1, and that of 232Th were 39 ± 5, 37 ± 5, 35 ± 5 Bq kg−1, respectively, in the soil of the Sites 1, 2, and 3. Gamma dose rate 1 m above the soil surface was 55, 51, and 40 nGy h−1 from Sites 1, 2, and 3, respectively. External dose rates in the rooms constructed of the bricks made of the soil from Sites 1, 2, and 3 were 161, 149, and 114 nGyh−1, respectively. DISCUSSIONS: Activity concentration values of 40K and 226Ra in the soil of Sites 1 and 2 were higher than that in the soil of Site 3. The relative rise of 40K was 43 % and 34 % and that of 226Ra was 85 % and 65 % respectively in these sites. Activity concentrations of 232Th in all these sites were in the background range. Gamma dose rate 1 m above soil surface of Sites 1 and 2 was 40 % and 30 % respectively higher than that from the soil of Site 3. The rise in activity of 40K and 226Ra and gamma dose from the Site 1 was greater than that from the Site 2. The least activity and dose were observed from the Site 3. Gamma dose in the dwellings made of fertilized soil bricks of Site 1 and Site 2 were respectively calculated to be 41 % and 32 % higher than that in the abodes made of unfertilized soil bricks of Site 3. CONCLUSIONS: Activity concentrations of 226Ra and 40K were observed to be enhanced in the fertilized farmlands of the NIAB. Outdoor and indoor gamma dose as radiological hazard were found to be increasing with the continuous addition of PF in the understudy farmlands. RECOMMENDATIONS: It is recommended that naturally occurring radioactive metal should be removed during the process of manufacturing of the PF from the PR. PROSPECTIVE: The rise in radioactivity in the farmlands due to the addition of the PF can be a source of direct or indirect exposure to radiation that may enhance cancer risk of the exposed individuals.
Show more [+] Less [-]Possible use of Serratia marcescens in toxic metal biosorption (removal) Full text
2012
Cristani, Mariateresa | Naccari, Clara | Nostro, Antonia | Pizzimenti, Alessia | Trombetta, Domenico | Pizzimenti, Francesco
BACKGROUND, AIM AND SCOPE: Metal pollution is a serious problem for environmental safety and programmes of monitoring and bioremediation are needed. Among the processes of bioremediation, the use of microbes to remove and degrade contaminants is considered a biotechnological approach to clean up polluted environments. AIM: The aim of this study was to evaluate the ability of Serratia marcescens in Pb, Cd and Cr removal and the potential use of these bacteria in toxic metal bioremediation from polluted environments. METHODS: A short-term study (120 min) was carried out to study the bacterial growth in the presence of sub-inhibitory concentrations of each metal analysed and the kinetics of metal biosorption in S. marcescens strain. In addition, metal influence on the biosynthesis of the red pigment ‘prodigiosina’ by S. marcescens was monitored. RESULTS: The results obtained in this study show metals biosorption by S. marcescens (range: 0.0133–0.213 μg/g for Pb; 0.097–0.1853 μg/g for Cd; and 0.105–0.176 μg/g for Cr) and confirm the possible use of this bacterium to realize bioremediation processes, especially for Pb removal, and as a bioindicator of metal pollution.
Show more [+] Less [-]Fine and ultrafine particles emitted from laser printers as indoor air contaminants in German offices Full text
2012
Tang, Tao | Hurraß, Julia | Gminski, Richard | Mersch-Sundermann, Volker
PURPOSE: Various publications indicate that the operation of laser printers and photocopiers may be associated with health effects due to the release of gaseous components and fine and ultrafine particles (UFP). However, only sparse studies are available that evaluate the possible exposure of office workers to printer emissions under real conditions. Therefore, the aim of our study was to assess the exposure of office workers to particulate matter released from laser printers and photocopiers. METHODS: Concentrations of fine particles and UFP were measured before, during, and after the operation of laser printing devices in 63 office rooms throughout Germany. Additionally, the particles were characterized by electron microscopy and energy-dispersive X-ray spectroscopy. RESULTS: A significant increase of fine particles and UFP was identified in ambient workplace air during and after the printing processes. Particle fractions between 0.23 and 20 μm emitted by the office machines significantly affect particle mass concentrations while printing 500 pages, i.e., during the printing process, PM0.23–20, PM2.5, and PM10 concentrations increased in 43 out of the evaluated 62 office rooms investigated. Additionally, a significant increase was observed in submicrometer particles, with median particle number concentrations of 6,503 particles/cm3 before and 18,060 particles/cm3 during the printing process. CONCLUSIONS: Our data indicate that laser printers and photocopiers could be a relevant source of fine particles and particularly UFP in office rooms.
Show more [+] Less [-]Genotoxicity potential of a new natural formicide Full text
2012
Cotelle, Sylvie | Testolin, Renan C. | Foltête, Anne-Sophie | Bossardi-Rissardi, Georgiana | Silveira, Rosilene A. | Radetski, Claudemir M.
BACKGROUND, AIM, AND SCOPE: Assessment of environmental impacts from pesticide utilization should include genotoxicity studies, where the possible effects of mutagenic/genotoxic substances on individuals are assessed. In this study, the genotoxicity profile of the new formicide Macex® was evaluated with two genotoxicity tests, namely, the micronucleus test with mouse bone marrow and Vicia faba, and a mutagenicity test using the Ames Salmonella assay. MATERIALS AND METHODS: The bacterial reverse mutation test (Salmonella typhimurium strains TA97, TA98, TA100, TA102, and TA1535), the Vicia root tip and mouse micronucleus tests were conducted according to published protocols. RESULTS: In the range of the formicide Macex® concentrations tested from 0.06 to 1.0 g L−1 (or mgkg−1 in the mouse test), no genotoxicity was observed in the prokaryotic or eukaryotic test organisms. However, at Macex® concentrations of 0.5 g L−1 and above a significant decrease in the mitotic index (P ≤ 0.05) in the V. faba was observed. Micronucleus formation was likewise increased in the test organism at concentrations starting at 2.0 g L−1. CONCLUSIONS: These data allow us to classify this natural formicide preparation as a product with no geno-environmental-impact when applied at recommended concentrations.
Show more [+] Less [-]New developments on emerging organic pollutants in the atmosphere Full text
2012
Balducci, Catia | Perilli, Mattia | Romagnoli, Paola | Cecinato, Angelo
BACKGROUND: The continuous progress in analytical techniques has improved the capability of detecting chemicals and recognizing new substances and extended the list of detectable contaminants widespread in all environmental compartments by human activities. Most concern is focused on water contamination by emerging compounds. By contrast, scarce attention is paid to the atmospheric sector, which in most cases represents the pathway of diffusion at local or global scale. Information concerning a list of organic pollutants is provided in this paper. METHODS: The volatile methyl tert-butyl ether and siloxanes are taken as examples of information insufficient with regard to the potential risk induced by diffusion in the atmosphere. Illicit drugs, whose presence in the air was ascertained although by far unexpected, are considered to stress the needs of investigating not solely the environmental compartments where toxic substances are suspected to display their major influence. Finally, the identification of two recognized emerging contaminants, i.e., tris(2-chloroisopropyl) phosphate and N,N-diethyl-m-toluamide, in aerosols originally run to characterize other target compounds is presented with the purpose of underlining the wide diffusion of the organic emerging contaminants in the environment.
Show more [+] Less [-]Modeling and optimization of reductive degradation of chloramphenicol in aqueous solution by zero-valent bimetallic nanoparticles Full text
2012
Singh, Kunwar P. | Singh, Arun K. | Gupta, Shikha | Rai, Premanjali
PURPOSE: The present study aims to investigate the individual and combined effects of temperature, pH, zero-valent bimetallic nanoparticles (ZVBMNPs) dose, and chloramphenicol (CP) concentration on the reductive degradation of CP using ZVBMNPs in aqueous medium. METHOD: Iron–silver ZVBMNPs were synthesized. Batch experimental data were generated using a four-factor statistical experimental design. CP reduction by ZVBMNPs was optimized using the response surface modeling (RSM) and artificial neural network-genetic algorithm (ANN-GA) approaches. The RSM and ANN methodologies were also compared for their predictive and generalization abilities using the same training and validation data set. Reductive by-products of CP were identified using liquid chromatography-mass spectrometry technique. RESULTS: The optimized process variables (RSM and ANN-GA approaches) yielded CP reduction capacity of 57.37 and 57.10 mg g−1, respectively, as compared to the experimental value of 54.0 mg g−1 with un-optimized variables. The ANN-GA and RSM methodologies yielded comparable results and helped to achieve a higher reduction (>6%) of CP by the ZVBMNPs as compared to the experimental value. The root mean squared error, relative standard error of prediction and correlation coefficient between the measured and model-predicted values of response variable were 1.34, 3.79, and 0.964 for RSM and 0.03, 0.07, and 0.999 for ANN models for the training and 1.39, 3.47, and 0.996 for RSM and 1.25, 3.11, and 0.990 for ANN models for the validation set. CONCLUSION: Predictive and generalization abilities of both the RSM and ANN models were comparable. The synthesized ZVBMNPs may be used for an efficient reductive removal of CP from the water.
Show more [+] Less [-]Speciation distribution and mass balance of copper and zinc in urban rain, sediments, and road runoff Full text
2012
Zuo, XiaoJun | Fu, Dafang | Li, He
Heavy metal pollution in road runoff had caused widespread concern since the last century. However, there are little references on metal speciation in multiple environmental media (e.g., rain, road sediments, and road runoff). Our research targeted the investigation of metal speciation in rain, road sediments, and runoff; the analysis of speciation variation and mass balance of metals among rain, road sediments, and runoff; the selection of main factors by principal component analysis (PCA); and the establishment of equation to evaluate the impact of rain and road sediments to metals in road runoff. Sequential extraction procedure contains five steps for the chemical fractionation of metals. Flame atomic absorption spectrometry (Shimadzu, AA-6800) was used to determine metal speciation concentration, as well as the total and dissolved fractions. The dissolved fractions for both Cu and Zn were dominant in rain. The speciation distribution of Zn was different from that of Cu in road sediments, while speciation distribution of Zn is similar to that of Cu in runoff. The bound to carbonates for both Cu and Zn in road sediments were prone to be dissolved by rain. The levels of Cu and Zn in runoff were not obviously influenced by rain, but significantly influenced by road sediments. The masses for both Cu and Zn among rain, road sediments, and road runoff approximately meet the mass balance equation for all rainfall patterns. Five principal factors were selected for metal regression equation based on PCA, including rainfall, average rainfall intensity, antecedent dry periods, total suspended particles, and temperature. The established regression equations could be used to predict the effect of road runoff on receiving environments.
Show more [+] Less [-]