2013  Vol. 30  No. 10

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Original Articles
Abstract:
[Objective] To explore the association between polymorphisms in nucleotide excision repair (NER) pathway genes and vinyl chloride (VC)-induced chromosomal damage in peripheral blood lymphocytes.

[Methods] Cytokinesis-block micronucleus (CBMN) assay was used to detect chromosomal damage in peripheral lymphocytes of 317 VC-exposed workers and 166 controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect 7 single nucleotide polymorphisms (SNPs) of 5 critical genes in NER pathways. The associations of these polymorphisms with chromosomal damage as well as the gene-exposure interaction were then analyzed.

[Results] The mean micronucleus frequency in the exposure group was (3.47& #177;2.65)‰, which was higher than that of the control workers[(2.51& #177;1.96)‰] (P<0.01). The SNPs of XPA Ala23Gly, XPC Ala499Val, XPC Lys939Gln, and XPF 5'-UTR T2063A were associated with the micronucleus (MN) frequency as an indicator of susceptibility (FR and 95%CI:1.20, 1.05-1.39; 1.17, 1.04-1.32; 1.23, 1.09-1.38; 0.75, 0.64-0.91, all P<0.01, respectively), and interacted with VC cumulated exposure doses. Moreover, the results of haplotype analysis showed higher MN frequencies in the workers carrying the PAT-CG/PAT-TG, PAT+TG/PAT+TG, PAT+CA/PAT+CA or PAT+TG/PAT+TA diplotype than the workers carrying the wild-type PAT-CA/PAT-CA (FR and 95%CI:2.45, 2.01-3.75; 1.08, 1.02-1.32; 1.35, 1.13-1.57; 1.57, 1.02-1.96, P<0.01 or P<0.05, respectively); while the workers with PAT-CA/PAT+CA had lowered risks of the studied damage (FR=0.25, 95%CI:0.12-0.57, P<0.01).

[Conclusion] VC can induce chromosomal damage even when the exposure level is lower than the national occupational health standard of China. The polymorphism of DNA repair genes in NER pathway may be associated with chromosomal damage induced by VC.

Abstract:
[Objective] To identify health risks to human beings caused by phthalates (PAEs) and di (2-ethyl hexyl) adipate (DEHA) in the source water and finished water in Hefei, China.

[Methods] Water samples were collected from the Western Chaohu Lake and two municipal waterworks A and B (including source water and finished water) of Hefei in level, wet, and dry periods. The PAEs and DEHA in water samples were determined by gas chromatography-mass spectrometry (GC/MS) combining solid-phase extraction technique, and a health risk assessment model recommended by US Environmental Protection Agency (EPA) was used to quantitatively evaluate carcinogenic risk and non-carcinogenic risk by the way of drinking.

[Results] Bis (2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), dimethyl phthalate (DMP), diethyl phthalate (DEP), and DEHA were detected in all collected samples and well within the limits of the National Standards for Drinking Water Quality (GB 5749-2006). Among them, DEHP and DBP were major pollutants, which took 60.22% and 21.43% respectively on average. No obvious differences were found in selected plasticizers across different water periods. The highest total contamination level was found in the wet period, followed by the dry period and the level period. The carcinogenic risk estimated from the water samples was 0.80& #215;10-6-2.72& #215;10-6, and the non-carcinogenic risk was 2.95& #215;10-3-1.04& #215;10-2. DEHP was the leading contributor to the calculated carcinogenic and noncarcinogenic risks, accounting for 99.0%-99.4% and 92.8%-93.8% of contributions, respectively.

[Conclusion] The source water and finished water in Hefei are polluted by PAEs and DEHA to various degrees of severity; however, the carcinogenic risk and the non-carcinogenic risk are at an acceptable level according to the US EPA's recommended limits.

Abstract:
[Objective] To measure and evaluate the eight-hour continuous equivalent A-weighted sound levels (LAeq.8 h), one-minute continuous equivalent A-weighted sound levels (LAeq.1 min), and continuous equivalent A-weighted sound levels over a work day (LAeq.T) of non-steady noise at work.

[Methods] LAeq.8 h was determined by personal noise dosimeter. LAeq.1 min was measured by environmental noise dosimeter. LAeq.T was calculated with LAeq.1 min. A Total of 239 workers exposed to non-steady noise in a pipeline manufacturing factory and a household appliance factory were investigated using LAeq.8 h. Workplace noise levels were measured using LAeq.1 min and LAeq.T.

[Results] The averages of LAeq.8 h in the two factories[(89.7& #177;3.8) dB(A) and (90.5& #177;5.7) dB(A)] were significantly higher than the averages of LAeq.T[(88.0& #177;2.4) dB(A) and (89.2& #177;3.6) dB(A) (P< 0.05 or P< 0.01)]. Sampling time errors of the values of LAeq.1 min were observed as compared with the values of LAeq.8 h. The differences between the mean values of LAeq.1 min and LAeq.8 h at most of the work locations were greater than 3 dB(A). The differences between the mean values of LAeq.T and LAeq.8 h at all work locations were less than 3.0 dB(A).

[Conclusion] LAeq.8 h is able to measure the non-steady noise level of workers. LAeq.T reflects actual noise levels of workers. LAeq.1 min may underestimate or overestimate noise levels.

Abstract:
[Objective] To explore the adverse effects of radon and its daughters on lymphocytes in thymus, spleen, peripheral blood (PB), bone marrow (BM), and provide experimental data for mechanistic investigation on radon-induced immune damage in rats.

[Methods] Fifteen male Wistar rats were divided to three groups with 5 rats in each group:1 control group and 2 exposure groups. The exposed rats were placed in a HD-3 multifunction ecological radon chamber at a cumulative radiation dose of 200 or 400 working level months (WLM). At the end of the exposure, the spleen and thymus of the rats were aseptically excised, and PB & BM were collected to obtain single cells. The total number and proportion of cells in BM and PB were counted. The level of reactive oxygen species (ROS), intracellular free calcium concentration, mitochondrial membrane potential (MMP), cell cycle, and the apoptosis in lymphocytes were also detected by fluorescence probe.

[Results] The 200 WLM radon exposure resulted in a statistically significant increase of lymphocytes in the PB in comparison with the control group[(6.84& #177;1.40)& #215;109/L vs. (3.34& #177;1.10)& #215;109/L, P< 0.01]; the same changes were found in the BM of the two exposure groups. The level of ROS of thymus lymphocytes in the 200 WLM group was significantly higher than that in the control group (P< 0.01). In the same group, the MMP of lymphocytes in BM and PB were significantly lower, and the intracellular Ca2+ concentration of lymphocytes of spleen and thymus were significantly higher than the corresponding indices of the controls (P< 0.01). The G0/G1 phase of thymocytes from the 200 WLM group was reduced and the S phase was prolonged; opposite results were observed in the splenocytes with baseline of the controls. The apoptotic rate of thymocytes in the 200 WLM group was (1.63& #177;0.46)%, significantly higher than that in the control group[(0.69& #177;0.64)%, P< 0.05]; but the same effect was not observed in the 400 WLM group.

[Conclusion] Radon and its daughters may cause toxic effects on immune cells and immune function of rats.

Abstract:
[Objective] To probe the DNA damages induced by a gasoline additive, methyl tert-butyl ether (MTBE), in occupational exposed population.

[Methods] Physical examination and questionnaire survey were conducted in 100 workers selected from 8 gas stations in South China. A 5 mL peripheral venous blood sample was collected from each worker. Serum and lymphocytes were separated. The content of serum MTBE was detected with gas chromatography-mass spectrometry (GC/MS). Peripheral blood lymphocyte DNA damage was analyzed by comet assay. The relationship between serum MTBE content and lymphocyte DNA damage was explored using Pearson correlation analysis.

[Results] All selected workers met the basic health requirements for gasoline station operators. The mean value of MTBE in the exposure group was (6.230& #177;2.369) μg/L, significantly higher than that in the control group, (5.164& #177;2.139) μg/L (P< 0.05). The mean value of Olive tail moment in the exposure group was (0.060& #177;0.045) μm, significantly higher than that in the control group, (0.039& #177;0.038) μm (P< 0.05). The results of Pearson correlation analysis showed a positive correlation between MTBE content and the degree of DNA damage (r=0.859, P< 0.05).

[Conclusion] There is a correlation between serum MTBE content and lymphocyte DNA damage.

Abstract:
[Objective] To investigate the level of chromium in the crops planted around leather industrial parks (LIPs), and to provide scientific data for the prevention and control of chromium pollution in food.

[Methods] Samples of crops planted in the vicinity of LIPs (36 samples) and in a control area (22 samples) were collected to determine the levels of chromium. The unqualified rate of chromium was calculated according to the Maximum Levels of Contaminants in Foods (GB 2762-2005). The degree of food pollution was evaluated using single factor pollution index.

[Results] The average levels of chromium in crops around the LIPs and in the control area were 0.74 mg/kg and 0.18 mg/kg respectively (P< 0.05). The unqualified rate of chromium in the crops samples from the LIPs was 16.66% which was significantly higher than that in the crops samples from the control area (0%) (P< 0.05). The single factor pollution indices for both wheat and corn were lower than 1.

[Conclusion] Some of the crops grown around the leather industrial parks are polluted by chromium, and it is possible to have adverse health effects on the exposed population.

Abstract:
[Objective] To investigate the smoking prevalence and tobacco-related knowledge, attitude, and practice (KAP) among college students, so as to provide scientific evidence to improve tobacco control in this population group.

[Methods] A questionnaire survey on KAP towards smoking and tobacco control was conducted among college students selected from 3 universities (1 medical college and 2 non-medical colleges).

[Results] A total of 2 500 college students were investigated and 2 472 questionnaires were valid (98.9% response rate). The smoking rate was 21.9% (542) for all the college students selected, in which 34.8% (506) were for males and 3.5% (36) were for females (P< 0.001). Smoking behavior was associated with the knowledge and attitudes about smoking and tobacco control (P< 0.05). The results of multivariate analysis showed that the risk factors of smoking behavior included male, in creasing age, non-medical students, township settlement, sophomore, poor awareness of tobacco hazards, tolerant of passive smoking, and positive attitude towards others smoking.

[Conclusion] The smoking behavior among the college students is related with the knowledge and attitude towards smoking and tobacco control.

Experiments
Abstract:
[Objective] To probe the antagonistic effect of alpha lipoic acid (α-LA) on the glutamate metabolism and transport disrupted by methylmercury.

[Methods] Twenty-four Wistar rats were randomly divided into 4 groups by weight (6 rats per group including 3 male and 3 female):a control group, a low-and a high-dose methylmercury groups, and an α-LA pretreatment group. The control and the methylmercury groups were treated by subcutaneous injection with 0.9% NaCl, and the pretreatment group was injected with 35 μmol/kg α-LA. Two hours later, the control group was peritoneally injected with 0.9% NaCl; the two methylmercury groups and the pretreatment group were peritoneally injected with 4, 12, and 12 μmol/kg CH3HgCl, respectively. The administration frequency of CH3HgCl was every 2 days for the α-LA pretreatment group, and every day (that was 5 times/week) for the two methylmercury groups. The administration protocol lasted for 4 weeks. Twenty-four hours after the last administration, the cerebral cortex was harvested to prepare 5% and 10% homogenates; the concentrations of Hg, Glu, Gln, as well as the activity of phosphate activated glutaminase (PAG), glutamine synthetase (GS), Na+-K+-ATPase, and Ca2+-ATPase were determined.

[Results] In comparison with the control group, the concentrations of mercury[(17.72& #177;1.36) μg/g tissue], Glu[(71.57& #177;10.87) μmol/g protein], and the PAG activity[(31.26& #177;4.38) μmol/(min& #183;g protein)] in the brain tissue of high-dose methylmercury treated rats were significantly increased (P< 0.01); the concentration of Gln[(0.15& #177;0.04) μmol/g protein] and the GS activity[(23.89& #177;3.60) U/g protein] were significantly decreased (P< 0.01); the activities of Na+-K+-ATPase[(4.03& #177;0.57) μmol/(h& #183;mg protein)] and Ca2+-ATPase[(2.21& #177;0.62) μmol/(h& #183;mg protein)] were significantly lowered (P< 0.01). The above-mentioned indicators' alterations were smaller in the α-LA treated group:the concentrations of Glu[(63.02& #177;3.33) μmol/g protein] and Gln[(0.20& #177;0.05) μmol/g protein]; activities of PAG[(26.03& #177;3.88) μmol/(min& #183;g protein)], GS[(34.05& #177;4.23) U/g protein], Na+-K+-ATPase[(5.52& #177;1.16) μmol/(h& #183;mg protein)],and Ca2+-ATPase[(3.27& #177;0.60) μmol/(h& #183;mg protein)]. The differences of the above indicators between the α-LA treated group and the high-dose methylmercury group showed statistical significance (P< 0.01 or P< 0.05).

[Conclusion] α-LA can serve as a protective agent against glutamate metabolism disrupted by methylmercury.

Abstract:
[Objective] To investigate the protective effects of α-lipoic acid (α-LA) on sucrose-induced liver oxidative damages in Goto-Kakizaki (GK) rats.

[Methods] Thirty-six eight-week-old male GK rats were randomly divided into 6 groups:1 negative control (no treatment), 1 positive control (30% sucrose solution), and 4 experimental (30% sucrose solution+daily α-LA supplementation of 25, 50, 75, or 100 mg/kg by gavage, respectively) groups. Nine weeks after the interference, changes in lipid peroxidation concentrations, antioxidases activity, and reactive oxygen species (ROS) levels in liver mitochondria were recorded.

[Results] The levels of malondialdehyde (MDA) and ROS increased significantly (P< 0.05), and the activities of superoxidase dismutase (SOD) and glutathione peroxidase (GSH-Px) in mitochondria of liver decreased remarkably in the positive control rats compared with those of the negative control rats (P< 0.05), which indicated that sucrose feeding obviously enhanced oxidative stress in the liver cells of GK rats. Compared with the positive control rats, the rats treated with 25 or 50 mg/kg α-LA showed significant declines in the levels of MDA and ROS and increases in the activities of GSH-Px and SOD in mitochondria of rat liver (P< 0.05), and the above antioxidative effects were superior to the similar indicators in the rats with 75 and 100 mg/kg α-LA interference.

[Conclusion] α-lipoic acid within a certain range of concentration may have a protective effect on the oxidative damage in liver cells of sucrose-induced GK rats.

Abstract:
[Objective] To evaluate changes in knowledge of occupational health among migrant workers in private enterprises in Cixi City before and after an intervention program, and to provide basis for developing health promotion strategies.

[Methods] Two hundred migrant workers from each of 2 private enterprises were selected by stratified random sampling strategy. An intervention on enterprise health policy, supportive environment, health education, and health services was implemented from November 2010 till December 2011. A questionnaire survey on awareness of occupational health was performed before and after the one-year intervention, including knowledge of occupational diseases, occupational hazards, occupational health protection, occupational health examination, and relevant laws and regulations.

[Results] The proportion of the migrant workers with correct understanding of occupational diseases rose from 70.25% before the intervention to 90.71% after the intervention (P< 0.05). The overall awareness rate of occupational health increased from 61.47% before the intervention to 86.38% after the intervention (P< 0.05). The occupational health awareness rate in migrant workers with junior high school education level increased from 49.41% to 85.93% (P< 0.05).

[Conclusion] Enterprises' policy of occupational health plays an important role in preventing the occupational hazards among migrant workers. Education and training are effective ways, such as a 10-minute class of occupational heath before regular safety meetings.

Investigations
Abstract:
[Objective] To investigate the levels and characteristics of occupational stress among offshore oil workers and analyze the main impact factors.

[Methods] A group of 134 offshore male oil workers (observation group) and 167 land-based male oil workers (control group) were enrolled by cluster sampling in September, 2012. A questionnaire survey was conducted among the workers with the Occupational Stress Inventory-Revised Edition (OSI-R).

[Results] The total scores of occupational stress and occupational stress reaction of the offshore oil workers were higher than those of the control group, and the score of personal resources was lower. The scores of occupational stress caused by physical environment and psychological stress reaction were 33.18 and 27.5, respectively, obviously higher than those of the control group. The offshore oil workers' occupational stress reaction was positively related to occupational stress and negatively related to personal resources. The main impact factors included role boundary, role insufficiency, physical environment, self-care, and education background.

[Conclusion] Offshore oil workers suffer from a high degree of occupational stress. Therefore, the impact factors of occupational stress should be considered in future health promotion.

Abstract:
[Objective] To investigate and analyze the occupational hazards in some small and micro enterprises in Yinzhou District, and to provide basis for occupational health service policy makings and all-round prevention & control of occupational hazards.

[Methods] According to the national work plan of general survey on occupational hazards, 2% small and micro enterprises in the Yinzhou District were randomly selected as study subjects to investigate the basic information, production technology, protective measures against occupational disease, and occupational hazards of the enterprises, as well as workers' exposure and occupational health surveillance.

[Results] The top three occupational hazards in the selected small and micro enterprises were noise, dust, and high temperature, accounting for 59.5%, 54.1%, and 18.9% of the total enterprises respectively. The qualified rates for industrial dust, physical factors, and chemical factors were 83.30%, 72.02%, and 76.90%, respectively.

[Conclusion] The small and micro enterprises have undervalued occupational hazards prevention. It is suggested to strengthen supervision of occupational hazards in small and micro-scale enterprises by improving engineering protection and personal protection measures.

Abstract:
[Objective] To know well about the current situation of occupational hazards in paint spraying workplace of wooden furniture factories and the efficiency of protection measures, so as to improve working conditions and protection levels.

[Methods] A field investigation was conducted to quantitatively and qualitatively analyze the ventilation and protection measures against harmful gases.

[Results] The unqualified rate of xylene concentration in the air of the selected workplace was 83%. Abnormal health examination indicators were reported for 8 workers, accounting for 10% of the total exposed workers. The wind speeds at 1 m distance in front of the exhaust hood and the side suction cover were 0.2-0.3 m/s and 0.3-0.4 m/s respectively, indicating poor protective effects.

[Conclusion] There are structural defects in the original ventilation protective devices of the paint spraying workshop. Improvement measures, such as overall confined laminar flow hood with a negative pressure airlock linking the outside, will enhance the protective effect for operators under the hood and also control pollution outside the hood.

Abstract:
[Objective] To explore the effects of ionizing radiation and other factors on hepatic function of radiation professionals.

[Methods] A total of 874 radiation professionals participating in the 2010-2011 annual physical examination of Guangxi were selected as the exposure group. Another 300 healthy individuals without exposure to radiation from the same physical examination were elected as the control group. Liver function indices of the two groups were detected. Single factor analysis and multi-factor analysis were adopted to analyze the data.

[Results] The differences in the abnormal rates of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), cholinesterase (CHE), total protein (TP), albumin (ALB), total bilirubin (TBIL), and direct bilirubin (DBIL) between the control group and the exposure group were of statistical significance (P< 0.05). The abnormal rates of DBIL, GGT, ALB in the radiation professionals of different service length were statistically different (P< 0.01). The levels of glutamyl transferase (GGT), ALT, AST, ALP, TBIL, and CHE for male radiation professionals were all higher than those for the female in the same group (P< 0.001). The level of DBIL in smokers was higher than in nonsmokers (P< 0.01). The DBIL level decreased with the increase of age (P< 0.01); in contrast, the CHE level increased with the increase of age (P< 0.01). The GGT level was positively correlated with radiation service length (r=0.109, P=0.001), and the TP level was negatively correlated with radiation service length (r=-0.128, P=0.000).

[Conclusion] Abnormal hepatic function is found in radiation professionals with high possibility, especially those with long-term radiation exposure history, and it is closely related to radiation service length. Smoking, gender, and age also have a certain effects on liver function.

Management and Supervision
Abstract:
As the development of Shanghai industry, a growing number of new materials and technologies are used, causing more complicated acute occupational poisonings. While the duties of the health authority has adjusted recently, there are new challenges to acute occupational poisoning emergency response. Problems like the lack of occupational hazards monitoring system and uneven distribution of emergency response resources are identified. This article discussed solutions for these problems, such as hazard-oriented monitoring work and integration of emergency response resources.
Experimental Technology
Abstract:
[Objective] Using mixed chemical modifiers to improve the determination of lead in blood and urine by graphite furnace atomic absorption spectrometry.

[Methods] Through comparing the effects of five chemical modifiers and optimizing the test condition of graphite furnace, lead in blood and urine were determined by directly diluting.

[Results] A mixture of 0.2% ammonium dihydrogen phosphate and 0.05% magnesium nitrate solution was used as chemical modifier for the blood samples containing lead. A mixture of 4% ammonium dihydrogen phosphate and 6% ascorbic acid solution was used as chemical modifier for the urine samples containing lead. The linear ranges of blood and urine lead determination respectively were 3-100 μg/L and 6.7-80 μg/L respectively. The detection limits were 0.9 μg/L and 2.0 μg/L respectively. The relative standard deviations (RSD) were less than 5%. The addition standard recovery rates were 92.1%-104.0%.

[Conclusion] Using mixed chemical modifier to facilitate lead determination in blood or urine is sensitive, accurate and of good reproducibility, low cost, and ease to popularize. This method is suitable for the detection of bulk samples.

Abstract:
[Objective] To establish a simple and rapid method for mercury ion detection.

[Methods] Variations of D660nm/D530nm before and after adding mercury ion were compared through the spectroscopy of colloidal gold and DNA system which was scanned with a spectrophotometer to determine the content of mercury ion.

[Results] The linear range of this method was 0.1-2.0 μg/L, the correlation coefficient (r) was 0.995, and the detection limit was 0.2 μg/kg.

[Conclusion] The method based on colloidal gold and DNA system is simple and rapid for mercury ion detection in food.

Reviews
Abstract:
Sports nutrition supplements are more and more accepted by the public in alleviating fatigue and enhancing athletic performance with appropriate usage. Varied sports supplements are developed to meet various requirements. This article reviewed recent advances in the effects of major sports supplements on athletic performance.
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