Study on the excretive ratio of Toluene Diisocyanate in mice feces

To detect the excretion ratio of Toluene Diisocyanate （TDI） in mice feces by HPLC. The chromatogram column is C18-ODS, the mobile phase is Acetonitrile -H2O （45 ： 55）, the flow rate is 1mL/min. The detection wavelength is 254 nm, and the quantity is determined by outer mark method. The linear relationship of concentrations of TDI was shown well in the range of 1.2 mol/L-5.2 mol/L, and the recovery ratio was 96.48%, precision degree within the day was under 2.9% and in the day it was under 3.37%. This method was simple, convenient and viable. And the result showed that the excretive ratio of TDI in mice feces was distinctly increased with the dosage given by p.o, which proved that feces were the chief mode of archetypal excretion of TDI given by p.o.     

苯和甲苯在盐水溶液中活度系数及其盐效应的研究

采用紫外分光光度法测定了24.0℃时苯和甲苯在CH3COONa,(NH4)2SO4,MgSO4,Na2SO4和Na2CO3水溶液中的活度系数(f),它们的lgf-Cs关系符合Setschenow盐效应公式,计算了苯和甲苯在上述5种盐水溶液中的盐析系数。     

High urine hippuric acid level among police working close to traffic in an urban area,Thailand: a preliminary study

Toluene is of particular concern because recent research indicating that toluene exposure can result in several toxicities. Hence, toluene exposure is of particular concern because of ongoing exposure to thousands of workers in the industrial plants. Determination of the urine hippuric acid level is accepted as a helpful for monitoring risk groups of workers. Apart from the industrial workers, there are other occupations with high risk for toluene exposure. In this study, we study another at-risk occupation, the police. In this study, 45 urine samples were obtained from 45 Thai police working close to traffic in an urban area for determination for urine hippuric acid level. The average urine hippuric acid level was 0.70 ± 0.70 mg/gCr, respectively. This average is significant higher than that of the control non-exposed Thais (P < 0.05). Working in the air pollution in the urban area can be health hazard for the police. Exposure to the toluene from automobile exhaust can be an important occupational problem for these police.     

Assessment of natural attenuation of aromatic hydrocarbons in groundwater near a former manufactured-gas plant, South Carolina, USA

 Shallow, anaerobic groundwater near a former manufactured-gas plant (MGP) in Charleston, South Carolina, USA, contains mono- and polycyclic aromatic hydrocarbons (MAHs and PAHs, respectively). Between 1994 and 1997, a combination of field, laboratory, and numerical-flow and transport-model investigations were made to assess natural attenuation processes affecting MAH and PAH distributions. This assessment included determination of adsorption coefficients (K _ad ) and first-order biodegradation rate constants (K _bio ) using aquifer material from the MGP site and adjacent properties. Naphthalene adsorption (K _ad =1.35×10^–7 m³/mg) to aquifer sediments was higher than toluene adsorption (K _ad =9.34×10^–10 m³/mg), suggesting preferential toluene transport relative to naphthalene. However, toluene and benzene distributions measured in January 1994 were smaller than the naphthalene distribution. This scenario can be explained, in part, by the differences between biodegradation rates of the compounds. Aerobic first-order rate constants of ¹⁴C-toluene, ¹⁴C-benzene, and ¹⁴C-naphthalene degradation were similar (–0.84, –0.03, and 0.88 day^–1, respectively), but anaerobic rate constants were higher for toluene and benzene (–0.002 and –0.00014 day^–1, respectively) than for naphthalene (–0.000046 day^–1). Both areal and cross-sectional numerical simulations were used to test the hypothesis suggested by these rate differences that MAH compounds will be contained relative to PAHs. Predictive simulations indicated that the distributions of toluene and benzene reach steady-state conditions before groundwater flow lines discharge to an adjacent surface-water body, but do discharge low concentrations of naphthalene. Numerical predictions were "audited" by measuring concentrations of naphthalene, toluene, and benzene at the site in early 1997. Measured naphthalene and toluene concentrations were substantially reduced and the areal extent of contamination smaller than was both observed in January 1994 and predicted for 1997. Measured 1997 benzene concentrations and distribution were shown to be relatively unchanged from those measured in 1994, and similar to predictions for 1997. Received: 26 June 1997 · Accepted: 25 August 1997     

High spatial resolution monitoring of benzene and toluene in the Urban Area of Taranto (Italy)

Atmospheric concentrations of benzene and toluene were assessed during three different seasons in the city of Taranto, using Radiello® diffusive samplers, in order to detect the most critical areas and to point out the sources contributing to pollution (vehicular traffic or industrial activities). High spatial resolution maps were built using a grid of 30 meshes drawn on the urban area of the city. For each mesh a monitoring site as representative as possible was chosen. Besides, in order to describe the highest levels of pollutants to which people is exposed, other 10 sampling sites were detected near high vehicular traffic crossroads or in particular critical zones of the city. The measurements of the concentration of these pollutants were carried out with Radiello® diffusive samplers for thermal desorption. The analysis of the results and the comparison between the map of vehicular traffic flows and the map of the concentrations of benzene suggested that in urban area the main benzene source is the traffic and the most significant pollution phenomena happens in zones characterized by narrow roads. Moreover it was possible to observe that high concentrations of benzene found in the NE zone of Taranto could be assigned to the industrial activities. This hypothesis was confirmed considering the diagnostic ratio between the toluene and benzene concentrations.     

Characterization of Chlorinated Tire‐Derived Mesoporous Activated Carbon for Adsorptive Removal of Toluene

A series of chlorinated mesoporous activated carbons were derived from waste tires by pyrolysis, activation, and chlorination at different temperatures. The physical and chemical properties of the samples were studied by Brunauer–Emmett–Teller (BET) analysis, Fourier Transform IR Spectroscopy (FT‐IR), point of zero charge measurement, thermogravimetric analysis, and by testing their behavior as adsorbents for toluene removal. Our results showed that the tire‐derived activated carbon samples have highly mesoporous volumes and surface areas, and chlorination treatment has a slight effect on the pore structure. Lewis acidity of the sample increases after chlorination and the chlorine content increases from 0.24 to 2.32% with chlorination temperature increasing from 50 to 400°C. The higher the chlorine content, the more is the toluene adsorption. In comparison with the commercial carbon (F‐400), all the samples have significantly higher adsorption capacity for toluene due to the presence of mesopores, inductive effect of the partial positive chemisorbed chlorine and resonance effects of C? Cl structures. The mesopores probably render easier diffusion of toluene molecule to inner carbon matrix and the strong π–π interaction between toluene and C? Cl resonance structure in the carbon significantly affects the interplay bonding process thus enhances the toluene removal.     

Joint interpretation of geoelectrical and volatile organic compounds data: a case study in a hydrocarbons contaminated urban site

As a result of a gasoline spill in an urban area, Electrical Resistivity Tomography (ERT), Electromagnetic Profiling (EMP) and Volatile Organic Compounds (VOC) methods were used in order to define the contamination plume and to optimize the drilling and soil sampling activities. The VOC anomalies (recent contamination) indicated that a gas station located at the study site is an active contamination source. The mature contaminated zones defined by ERT and EMP methods corresponded with low resistivity anomalies due to degradation process of the hydrocarbons contaminants. The ERT, EMP and VOC results were integrated on a map, allowing the final configuration of contamination plumes and the optimization of drilling and soil/free-product sampling. Laboratory analyses of free-product samples suggest the existence of more than one contamination event in the site, with the presence of recent and degraded-hydrocarbon contaminants classified in the gasoline range. This study shows the advantages of joint application of ERT, EMP and VOC methods in sites with active contamination source, where the existence of recent and mature contaminants in subsoil is assumed.     

The effects of TDI on mice bone marrow cells

Objective： To test the effects of TDI on mice bone marrow cells. Methods： The effects of TDI were studied by laser scanning confocal microtechnique to investigate the form changing of the mice bone marrow cell and genotoxicity test-chromosomal aberration test and sister chromatic exchange （sce） test. Results： The 1/16 LC50 and 1/8 LC50 dosage of TDI had no significant effect on the fluorescence pixels of RNA/DNA by laser scanning confocal microtechnique to investigate the chromosoma laberration rate and the frequencies of sister chromatic exchange of the mice （P〉0.05）. But both 1/4 LC50 and 1/2 LC50 dosage had significant effect on the fluorescence pixels of RNA/DNA by laser scanning confocal microtechnique to investigate the chromosoma laberration rate and the frequencies of sister chromatic exchange of the mice （P〈0.01）. Conclusions： TDI has the genetic toxicity.