Benzene ; toxicity ; Epigenesis, Genetic ; Humans

Benzene is classified as Group 1 carcinogen by IARC. It has been found that benzene induces hematotoxicity even in low dose exposure. The identification of key events during benzene induced hematotoxicty leads to adjustment of occupational exposure limits of benzene. In this review, we focus on the exposure, metabolism, target organs, key epigenetic changes, toxicty effects and end points of low-dose chronic benzene exposure induced hematotoxicity and finally discuss the perspectives on the future study of this area.
Benzene ; toxicity ; Carcinogens ; toxicity ; Epigenesis, Genetic ; Humans ; Occupational Exposure

Benzene ; toxicity ; Gene Expression Profiling ; Oligonucleotide Array Sequence Analysis

Benzene ; toxicity ; Carcinogens ; toxicity ; Chromosome Aberrations ; Genetic Predisposition to Disease ; Humans ; Leukemia ; chemically induced ; genetics

Benzene ; toxicity ; Humans ; Male ; Middle Aged ; Occupational Exposure ; Thrombocytopenia ; chemically induced

Adult ; Benzene ; toxicity ; Female ; Humans ; Male ; Occupational Exposure ; T-Lymphocytes, Regulatory ; drug effects ; Young Adult

Amifostine ; pharmacology ; Animals ; Benzene ; toxicity ; Blood ; drug effects ; Blood Cell Count ; Male ; Mice ; Random Allocation

OBJECTIVETo measure the acute toxicity of halogenated benzenes to bacteria in natural waters and to study quantitative relationships between the structure and activity of chemicals.

METHODSThe concentration values causing 50% inhibition of bacteria growth (24h-IC50) were determined according to the bacterial growth inhibition test method. The energy of the lowest unoccupied molecular orbital and the net charge of carbon atom of 20 halogenated benzenes were calculated by the quantum chemical MOPAC program.

RESULTSThe log1/IC50 values ranged from 4.79 for 2,4-dinitrochlorobenzene to 3.65 for chlorobenzene. A quantitative structure-activity relationship model was derived from the toxicity and structural parameters: log1/IC50 = -0.531(E(LUMO)) + 1.693(Qc) + 0.163(logP) + 3.375. This equation was found to fit well (r2 = 0.860, s = 0.106), and the average percentage error was only 1.98%.

CONCLUSIONHalogenated benzenes and alkyl halogenated benzenes are non-polar narcotics, and have hydrophobicity-dependent toxicity. The halogenated phenols and anilines exhibit a higher toxic potency than their hydrophobicity, whereas 2,4-dinitrochlorobenzene is electrophile with the halogen acting as the leaving group.

Aliivibrio fischeri ; drug effects ; Benzene ; chemistry ; toxicity ; Halogens ; chemistry ; Quantitative Structure-Activity Relationship ; Rivers ; chemistry ; microbiology ; Toxicity Tests, Acute ; Water Pollutants, Chemical ; chemistry ; toxicity

Adult ; Benzene ; toxicity ; Bone Marrow ; drug effects ; pathology ; Bone Marrow Cells ; Humans ; Leukemia, Monocytic, Acute ; chemically induced ; pathology ; Male

OBJECTIVETo evaluate the benzene exposure level and cytopenia among the benzene exposed workers in Shanghai, China and to analyze the influential factors for the health of benzene-exposed workers.

METHODSA total of 3314 benzene-exposed workers, who were from 85 benzene-related enterprises selected by stratified random sampling based on enterprise sizes and industries, were included in the study. The time-weighted average (TWA) concentration of benzene in each workshop was measured by individual sampling and fixed point sampling, and the benzene exposure level in workshop was evaluated accordingly. The occupational health examination results and health status of benzene-exposed workers were collected.

RESULTSThe median of TW A concentrations of benzene was 0.3 mg/m3. The TWA concentrations measured at 7 ( 1.4%) of the 504 sampling points were above the safety limit. Of the 7 points, 3 were from large enterprises, 2 from medium enterprises, and 2 from small enterprises; 3 were from shipbuilding industry, 1 from chemical industry, and 3 from light industry. Of the 3314 benzene-exposed workers, 451 ( 13.6%) had cytopenia, including 339 males ( 339/2548, 13.3%) and 112 females ( 112/766, 14.6% ). There were significant differences in the incidence rates of leukopenia and neutropenia among the benzene-exposed workers of different sexes and ages (P<0.05); there were significant differences in the incidence rate of cytopenia among the benzene-exposed workers of different ages and working years ( P<0.05 ); there were significant differences in the incidence of neutropenia among the benzene exposed workers of different working years ( P<0.05).

CONCLUSIONMonitoring and intervention measures should be enhanced to protect the benzene-exposed workers in the large enterprises in shipbuilding industry and medium and private enterprises in chemical industry from occupational hazards.

Adolescent ; Adult ; Benzene ; toxicity ; China ; epidemiology ; Female ; Humans ; Male ; Middle Aged ; Occupational Exposure ; Pancytopenia ; chemically induced ; epidemiology ; Young Adult