Research progress on content and detection methods of microplastics/nanoplastics in biological samples / 环境与职业医学

Plastic products are widely used in various fields, and the discarded plastics in the environment can be degraded into microplastics (MPs) or even nanoplastics (NPs), which significantly increases the risk of organism exposure. MPs/NPs have been found in aquatic organisms, birds of prey, and even humans. The detection of plastic particles in biological samples is more complicated than that in environmental samples. Biological samples are mainly composed of various organic substances such as proteins and lipids, which makes the pretreatment process particularly critical. Effective detection and accurate quantification of MPs/NPs are crucial to health risk assessment. In this paper, the exposure levels and composition of MPs/NPs in different tissues and organs of the human body, aquatic organisms, and birds of prey were reviewed. The digestion of biological samples (acids, bases, enzymes, and hydrogen peroxide digestion protocols) and MPs/NPs identification methods (spectroscopy and chromatography) were compared and their advantages and disadvantages were assessed, providing a methodological basis for plastic exposure risk assessment and pollution control.

Associations between urinary paraben levels and obesity of 10-year-old children / 环境与职业医学

Background Parabens, a widely used class of preservatives, are suspected to be potential obesogens as emerging endocrine disrupting chemicals with reproductive and developmental toxicity. Objective To analyze five urinary parabens (PBs) and estimate the associations of exposure to PBs with adiposity measures in 10-year-old school-age children. Methods A total of 471 school-age children aged 10 years from the Sheyang Mini Birth Cohort were enrolled in this study. A questionnaire survey was conducted to collect socio-demographic information, physical activity, and dietary intake. Weight, height, and waist circumference of children were measured, and age- and sex-adjusted body mass index (BMI-Z score) was calculated. Spot urine samples were collected during the follow-up visits. Urinary concentrations of five PBs including methyl-paraben (MeP), ethyl-paraben (EtP), propyl-paraben (PrP), butyl-paraben (BuP), and benzyl-paraben (BzP) were detected by gas chromatography-tandem mass spectrometry (GC-MS/MS). Generalized linear models (GLMs) and Bayesian kernel machine regression (BKMR) models were applied to estimate associations of individual/overall urinary PBs concentrations with BMI Z-score and waist circumference. Results The positive rates of selected five urinary PBs were in the range from 78.98% to 98.94%. The urinary PBs concentrations (geometric mean) were in the range of 0.31-5.43 μg·L−1. The children's BMI Z-score and waist circumference (mean ± standard deviation) were (0.56±1.40) and (67.62±10.07) cm respectively. The GLMs results showed that the urinary BzP concentration was negatively associated with waist circumference (b=−0.08, 95%CI: −0.14, −0.02; P=0.01). In sex-stratified analysis, the urinary concentration of BzP was negatively associated with BMI-Z score (b=−0.59, 95%CI: −0.88, −0.30; P<0.001) and waist circumference (b=−0.80, 95%CI: −1.23, −0.37; P<0.001) in boys, but not in girls. The BKMR results also found significant negative correlations of urinary BzP concentrations with BMI-Z score and waist circumference, which were consistent with the GLM results. Conclusion The selected 10-year-old children are extensively exposed to PBs in the study area. Furthermore, childhood PBs exposure may have potential impacts on childhood adiposity measures with sex-specific effects.

A modal study of the effect of adjusting density exposure steps on image quality and radiation dose in digital mammography / 中华放射学杂志

Objective:To investigate the effect of adjusting density exposure steps on image quality and radiation dose in digital mammography.Methods:Using the automatic exposure control (AEC) mode of the digital mammography machine, five different gland thicknesses of 4.3, 5.3, 6.3, 7.3, and 8.3 cm were simulated by attaching 0, 1, 2, 3, and 4 PMMA plexiglass plates under the RMI-156 modal body, and the density exposure steps were adjusted to -3, -2, -1, 0, 1, 2, 3, and 4 for each thickness. The target/filter combination, tube voltage, tube current, incident body surface dose (ESD), incident surface air kerma (ESAK), half-value layer (HVL) and the average glandular dose displayed by the device (displayed AGD) were recorded at each step and thickness, and the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), figure of merit (FOM) and the calculated average glandular dose (calculated AGD) were calculated. Then, the display effects of simulated fibers, simulated calcifications and simulated masses within the modal body were scored subjectively, and the changes in image quality and radiation dose at different steps were analyzed, and the relationships between ESD and ESAK, displayed AGD and calculated AGD, and displayed AGD/ESD and calculated AGD/ESAK were analyzed. A linear fit was used for the steps with SNR, CNR, and FOM, and an exponential function curve fit was used for the steps with mAs, ESAK, and calculated AGD. The differences between ESD and ESAK, displayed AGD and calculated AGD, and displayed AGD/ESD and calculated AGD/ESAK were analyzed by paired-samples t test. Results:The CNR and SNR of mammographic images rose and fell by about 8% with each increase or decrease of one step. The scores of image simulated fibers, simulated calcifications, and simulated masses showed an overall upward trend with increasing steps, but there were still cases where the scores decreased with increasing grades. FOM varied from 97% to 104% at each grade with little variability. ESD, ESAK, displayed AGD, and calculated AGD, which could measure radiation dose, showed an exponential trend of increasing function with increasing steps, with a variation of about 63% to 165%. There were statistically significant differences ( t=-9.61, P=0.001) between ESD (15.14±10.08) and ESAK (16.66±11.07). However, there were no statistically significant differences ( t=1.20, P=0.240) between displayed AGD and calculated AGD, which were 3.66±2.18 and 3.61±1.99, respectively. Conclusions:The adjustment of density exposure steps can make the image quality change linearly and the radiation dose change exponentially with increasing speed, and the mode and magnitude of the adjustment are appropriately stable with high application value.

Peripheral circulation and peripheral nerve injury in workers exposed to vibration at two different frequencies / 环境与职业医学

Background Hand-arm vibration disease is harmful to human body, but there are no effective diagnosis and treatment so far, and current occupational exposure limits underestimate the health damage caused by high-frequency vibration exposure. Objective To evaluate and compare the damage to workers' peripheral circulation and peripheral nerve caused by different frequencies of vibration operation. Methods Drilling workers (n=187) from a mining company in Shandong Province and golf club head grinding workers (n=228) from a sports equipment factory in Guangdong Province were selected as study subjects. Hand symptoms were investigated. SV106 vibration meter was used to measure the target operation-associated vibration frequency spectrum. The 8 h energy-equivalent frequency weighted acceleration, cumulative vibration exposure level (CVEL), and the working age related to causing white finger in 10% of an exposed group were calculated. Result The study subjects were all male. More grinding workers reported hand symptoms than the drilling workers, e.g. peripheral circulation injury (52.6% vs 19.3%), peripheral nerve injury (71.5% vs 23.0%), hand stiffness (64.0% vs 7.0%), and deformed fingers (69.7% vs 4.3%) (all P<0.001). The main vibration frequencies of grinding operation (500-800 Hz) were much higher than those of drilling operation (125~160 Hz). CVEL and working age of vibration exposure showed a linear rising relationship with the cumulative prevalence rate of peripheral circulation and peripheral never injury, the fitting lines all showed good fitting effects (R2=0.812-0.988), and the slope of the fitting line of the grinding workers was larger than that of the drilling workers. The working age of vibration exposure associated with 10% cumulative prevalence of white finger was shorter in the grinding workers than in the drilling workers (6.81 years vs 10.27 years). According to the ISO prediction formula, the working age of vibration exposure was associated with 10% white finger prevalence shorter in the drilling workers than in the grinding workers (3.12 years vs 8.23 years). Conclusion Both the vibration exposure level and the prevalence of hand symptoms are high in two groups of workers with different vibration frequencies, and vibration exposure at a higher frequency tends to have severer damage to workers' hands.

Occupational Health Risk Assessment of Benzene, Toluene, and Xylene in Shanghai / 生物医学与环境科学（英文）

Objective@#This study was designed to conduct a retrospective and systematic occupational health risk assessment (OHRA) of enterprises that used benzene, toluene, and xylene (BTX) in Shanghai, China.@*Methods@#All data for the study were obtained from 1,705 occupational health examination and evaluation reports from 2013 to 2017, and a semiquantitative model following Chinese OHRA guidelines (GBZ/T 298-2017) was applied for the assessment.@*Results@#The selected enterprises using BTX were mainly involved in manufacturing of products. Using the exposure level method, health risk levels associated with exposure to BTX were classified as medium, negligible, or low. However, the risk levels associated with benzene and toluene were significantly different according to job types, with gluers and inkers exhibiting greater health risks. For the same job type, the health risk levels assessed using the comprehensive index method were higher than those using the exposure level method.@*Conclusion@#Our OHRA reveals that workers who are exposed to BTX still face excessive health risk. Additionally, the risk level varied depending on job categories and exposure to specific chemicals. Therefore, additional control measures recommended by OHRA guidelines are essential to reduce worker exposure levels.

The exposure levels of phthalic acid esters in population: a review / 预防医学

@#Phthalic acid esters (PAEs) are commonly used plasticizers and solvents. Human body is exposed and absorbed mainly through diet, skin and air inhalation. The biological samples such as urine, blood, saliva, semen and breast milk generally contain PAEs and their metabolites, but the concentrations of PAEs metabolites vary in different samples. In the general population, the levels of PAEs are higher in children than in adults, and higher in women than in men; the levels of PAEs are higher in the occupational population than in the general population. In this paper, the research of PAEs related human biomonitoring in the general population and occupational population at home and abroad is reviewed, so as to provide the basis for reducing the exposure of PAEs and related health risk.

Pollution， human exposure and harmful effects of neonicotinoid pesticides / 上海预防医学

Neonicotinoid is a kind of neuroactive pesticide， and it has become the most widely used pesticide in the world. In recent years， neonicotinoid has been detected in the environment and food， suggesting that human can be exposed to this kind of pesticide through drinking water， ingestion and respiration， which poses potential health hazards to human. However， there is no comprehensive report on the pollution level of neonicotinoid pesticides in the environment and food and the impact on human health. In this paper， the pollution status， population exposure level and potential health risks of neonicotinoid pesticides in water， air and food were reviewed. We found that neonicotinoid residues are widespread in fruits and vegetables， of which imidacloprid has the highest detection rate. Except for a few samples with excessive neonicotinoid detection， the detection level in most samples did not exceed national food safety standards. A variety of neonicotinoid pesticides have been detected in the air， surface water， tap water and drinking water. External exposure studies in the population have shown that ingestion is the main route of exposure to neonicotinoid， and the external exposure level is much lower than its chronic reference dose. The internal exposure study mainly detected the concentration of neonicotinoid pesticides and their metabolites in urine. A variety of neonicotinoid pesticides and their metabolites are detected in urine， and the concentration range is ng/ml level. Internal exposure studies found that the detection rate of thiamethoxam and dinotefuran in urine is higher， and the detection rate of neonicotinoid in Asian countries is higher than that in European and American countries. Occupational exposure studies found that neonicotinoid exposure levels increased after pesticide spraying， and the exposure levels in rural areas where pesticides were commonly used were higher than those in neighboring urban areas. Animal experiments have found that neonicotinoid pesticides have reproductive toxicity， genetic toxicity， neurotoxicity， immunotoxicity， liver toxicity and nephrotoxicity to non-target organisms. Cell experiments suggest that neonicotinoid is an endocrine disruptor. The symptoms of acute exposure in humans are related to the exposure dose， route and physical condition of the exposed person， which ranges from mild symptoms （nausea， vomiting， headache and diarrhea） to death. Population epidemiological studies have shown that chronic exposure to neonicotinoid pesticides is associated with adverse health effects in humans such as neonatal tetralogy of Fallot， anencephaly， and adverse mental symptoms.

Association between Respirable Dust Exposure and Respiratory Health among Cement Workers

@#Introduction: Cement industry contributes to the major constituent of airborne dust in the atmosphere. This study aims to determine the level of respirable cement dust exposure associated with workers’ respiratory health. A cross-sectional study was carried out among 84 administration workers as the comparative group and 84 manufacturing workers as the exposed group. Method: A set of validated questionnaires was used to obtain some pertained background information as well as respiratory symptoms among the respondents. Personal Air Sampling Pump was used for assessing personal exposure towards cement dust in 8 hours. For lung function performance, a Spirometry test was carried out and Fractional Exhaled Nitric Oxide (FENO) test was conducted to assess airway inflammation. Results: The median for personal exposure level to respirable dust of manufacturing workers was 2.68 (5.90) mg/ m3 with range 0.351 to 10.60 mg/m3. The lung function abnormality among the manufacturing workers was FVC% (PR=3.82, 95% CI=1.52-9.58) and FEV1% (PR=5.16, 95% CI=1.65-16.10). Cough was reported to occur the most likely among the manufacturing workers (PR=2.40, 95% CI=1.12-5.15). After adjusting the smoking status, the prevalence of phlegm and cough were 35.7% and 29.8% respectively. 16.7% of manufacturing workers recorded a high level of FENO. The increasing exposure to respirable dust significantly reduces the FVC% of manufacturing workers (r=-0.36, p=0.05). Conclusion: The personal exposure to respirable cement dust increases the risk of lung impairment by highly developing respiratory health symptoms, reducing lung function level and increasing the higher level of airway inflammation among highly exposed workers.

Evaluation on occupational exposure to whole body vibration in workers of a hydroelectric power station / 中国职业医学

OBJECTIVE: To examine the level of occupational exposure to whole body vibration( WBV) in a hydroelectric power station,and evaluate its effects on workers' health. METHODS: A hydroelectric power station in Hangzhou City was chosen as study subject by using judgment sampling method. The level of WBV exposure to workers and high vibration level areas were measured,and the vibration frequency was analyzed. The comfort and allowing duration of occupational exposure in WBV exposed workers was evaluated. RESULTS: The median root-mean-square of accelerometer acceleration of WBV exposure in generator floor,turbines-floor,middle-floor,hydraulic floor of the hydroelectric power station were 0. 894,0. 995,1. 095 and 0. 904 m/s~2,respectively. The central frequency of WBV in this station was 1. 25 Hz. Among the 105 monitoring spots,8. 6% of WBV exposed workers of the spots did not perceive or feel uncomfortable,but 91. 4%of them felt uncomfortable or very uncomfortable. Only 12. 4% of the WBV exposed workers tolerated more than 8 hours of WBV occupational exposure. CONCLUSION: There is an occupational hazard of WBV in this hydroelectric power station.The low frequency vibration with central frequency below 1. 25 Hz is the key control point of the WBV of this hydroelectric power station.

Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries

OBJECTIVES: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. METHODS: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. RESULTS: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). CONCLUSION: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.

Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries

OBJECTIVES: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. METHODS: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. RESULTS: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). CONCLUSION: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.

Investigation and Analysis on the Disposal of Medical Waste in Village / 中华医院感染学杂志

OBJECTIVE To know the status of management knowledge and disposal process of medical waste in village.METHODS Questionnaire was conducted among crowds randomly selected from Huishi,taipin,Gangou and Hepan town in Huining country of GanSu province.RESULTS The understanding rate of management regulation of medical waste among crowd in these four town was 12.31%;The touching opportunity to medical waste was very high;When medical waste was manipulated,people of chooseing to bury accounted for 12.15%,choosing to throw 43.35%,choosing localized manipulate accounted for 4.43%;The phenomenon of throwing medical waste was very serious(85.77%).CONCLUSIONS The understanding rate of management regulation of medical waste are not high,wehereas the touching opportunity was very high in the village.At the same time,the phenomenon of throwing medical waste was very serious and correct manipulating rate are not high.So we should strengthen the education of correlated policy,formulate eligible manipulating method,improve and consummate scientific management system of the medical waste in village.

Exposure Level of Trichloroethylene in Stevens-Johnson Syndrome Due to Occupational Exposure: 3 Case Reports and a Review of Other Cases / 대한산업의학회지

BACKGROUND: Trichloroethylene (TCE) has been reported to be related to severe generalized exfoliative dermatitis frequently accompanied by toxic hepatitis. The measurements of environmental exposure were limited in the previous case reports and the reported exposure values were also diverse. We reviewed three cases of Stevens-Johnson syndrome associated with TCE. The work environment was measured by the Korea Occupational Safety and Health Agency (KOSHA) after the cases occurred. From the study results, we intended to clarify the relationship between TCE exposure level and Stevens- Johnson syndrome. CASE REPORT: Case 1. A 24-year-old Filipino female worker developed a skin rash 35 days after starting to use TCE for degreasing. The skin rash developed into a bullous eruption and the liver function findings were abnormal. She was diagnosed with Stevens-Johnson syndrome and toxic hepatitis. She died of hepatic failure 39 days after the onset of the first symptom. She had no previous history of taking medicine or viral infection. The work environment measured 22.0 to 32.3 ppm (personal exposure level) with TWA. Case 2. A 47-year-old Korean male worker developed a skin rash, 20 days after starting to use TCE for degreasing. The skin rash developed into a bullous eruption and the liver function findings were abnormal. He was diagnosed with Stevens-Johnson syndrome, toxic hepatitis and sepsis. He died of hepatic failure and sepsis 42 days after the onset of the first symptom. He had no previous history of taking medicine or viral infection. The work environment measured 30.1 ppm (personal exposure level) and 116.5~229.7 ppm (area exposure level close to the degreasing machine) with TWA. Case 3. A 22-yearold Vietnamese female worker developed a skin rash 30 days after starting to use TCE for degreasing. The skin rash developed into a bullous eruption and the liver function findings were abnormal. She was diagnosed with Stevens-Johnson syndrome and toxic hepatitis. Her symptoms improved and she was discharged 37 days after the onset of the first symptom. She had no previous history of taking medicine or viral infection. The work environment measured 107.2 ppm (personal exposure level) with TWA. DISCUSSION: These three case reports and the previously reported cases indicated that the majority of people susceptible to TCE develops Stevens-Johnson syndrome after high-level TCE exposure (above the TWA occupational exposure limit of 50 ppm). Therefore, work environmental survey and improvements to the TCE degreasing process are essential to prevent high exposure. Furthermore, considering the consistency of the latency period in symptoms and the possibility of sensitization in low-level exposure, we recommend that the first specific health examination also should be conducted 1 month after workers have commenced working.

Prevalence of Occupational Asthma and Exposure Level of Pharmaceutical Dust of Workers in a Pharmaceutical Company / 대한산업의학회지

OBJECTIVES: After the investigation of one worker with occupational asthma, we surveyed the prevalence of occupational asthma and the exposure level of pharmaceutical dust of 32 workers in a pharmaceutical company. METHODS: Thirty-two of the 90 employees participated in the survey which consisted of questionnaire, blood sampling, spirometry and skin prick tests with 8 common allergens as well as 9 antibiotics and 2 enzymes. Various indices of the working environment were also measured. Subjects who had a symptom suggestive of work-related asthma or positive skin prick test were further investigated by PC20 methacholine. Nine subjects who had a PC20 result of 16 mg/ml or less (n=7) or had work-related symptoms and positive skin prick test (n=2) were referred to undergo a specific bronchial provocation test to pharmaceutical dust in an academic allergic disease center. RESULTS: Eleven of 32 workers (34.4%) had a work-related symptom suggestive of occupational asthma. Ten (31.2%) showed positive skin prick test. 8 (25.0%) had a PC20 result of 16 mg/ml or less (indicative of significant bronchial hyperresponsiveness), and 5 (15.6%) had a positive result on the specific bronchial provocation test. Exposure levels of stuffing, input of raw materials and screening process were relatively high. CONCLUSIONS: This survey showed that pharmaceutical workers have an increased risk of occupational asthma. Although pharmaceutical factories maintain a relatively good working environment, careful control of respiratory tract exposures, especially during stuffing, input of raw materials and screening process, is important to prevent occupational asthma. Pharmaceutical workers need to undergo regular skin prick and methacholine bronchial provocation tests, as well as asthmatic symptom survey, to ensure the early detection and prevention of occupational asthma.

Acquried Dyschromatopsia in Women Workers in Shoe Manufacturing Who were Exposed to Organic Solvents / 대한산업의학회지

OBJECTIVES: This study was undertaken to investigate the relationship between color vision defects and occupational exposure to mixed organic solvents in women workers who were engaged in the shoe manufacturing industry. METHODS: A total of 173 women workers were involved in this study, 85 of whom were exposed to mixed organic solvents and were defined as the exposed group, and 88 workers comprised the non-exposed control group. The patients were questioned as to their drinking history, the year in which they were exposed and whether they had eye symptoms of blurred vision, eye fatigue, and eye irritation. The exposed workers in the shoe manufacturing factory were engaged in 3 work areas which were pasting, trimming, and cleaning. Their Color vision was assessed using the Hahn's double 15 hue test under standard illumination and their current and cumulative exposure levels were measured. RESULTS: The prevalence of color vision defect was 21.2% in the exposed group and 8.0% in the control group, and the blue-yellow defect was found to be 5.9 % in the exposed group. The logistic regression for the acquired dyschromatopsia and color confusion index showed that there were no variables that had significant relationships. Eye symptoms were more frequently developed in the exposed group. CONCLUSIONS: There is a possibility of developing color vision defects when workers are exposed to mixed organic solvents. However, the results of the color confusion index showed that there was no significant relationship to the cumulative exposure level, because of the low exposure level and high occupational turn over rate of the workers. Because the workers in the present study were exposed to low level solvents it will be necessary to study workers exposed to higher levels of organic solvents.

A Study on the Correlation between Categorization of the Individual Exposure Levels to Agent Orange and Serum Dioxin Levels Among the Korean Vietnam Veterans / 예방의학회지

OBJECTIVES: In an epidemiologic study on the health impact of Agent Orange exposure, the valid estimation of exposure level is the most important step. Based on recent studies, we examined the correlation between exposure levels categorized by personal exposure estimates and serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD, Dioxin), exploring the possibility of utilizing the exposure level as a surrogate for the estimate of exposure to agent orange. METHODS: During the study period (Jan 1996-Feb 1996), blood specimens of 745 subjects taken randomly among 1,329 persons and kept frozen, were analyzed for 2,3,7,8-TCDD and six other dioxin congeners. The serum dioxin and congeners were measured in 1998 by CDC ,adjusted for serum lipids. We categorized the total exposure scores into five groups based on Agent Orange exposure data collected by interview and military records. Pearson and Spearman's correlation coefficients & multiple regression analysis were used to identify the relationship of the exposure level categorized with serum concentration of 2,3,7,8-TCDD, and six other dioxin congeners. RESULTS: Dioxin and the other congeners, except 1,2,4,6,7,8-HpCDD, showed significant correlations to exposure categories (p<0.005); 2,3,7,8-TCDD and OCDD showed positive correlations, whereas the other congeners did negative. The values of 2,3,7,8-TCDD differed according to exposure category and proportionally increased from the low exposure group to the high, a dose-response relationship, even after other possible confounding variables were adjusted for. In multiple regression analysis, age(beta=0.033), dioxin(beta=0.433), 1,2,3,7,8-PeCDD(beta=0.998), 1,2,3,4,7,8-HxCDD(beta=0.773), 1,2,3,6,7,8-HxCDD(beta=0.255), 1,2,3,7,8,9-HxCDD(beta=3.468), 1,2,3,4,6,7,8-HpCDD(beta=0.109) were found to be significantly related to the total exposure score(p<0.005). CONCLUSION: This study demonstrated that the use of such categorizations as a surrogate measure of agent orange exposure in identifying exposure degrees in a health impact study is valid.

Effect of Aldehyde dehydrogenase2 (ALDH2) Genotypes in Urinary Hippuric Acid Excretion as a Biological Exposure Index of Toluene / 대한산업의학회지

We investigated toluene exposure level, urinary hippuric acid concentrations, subjective symptoms and genotype of ALDH2 DNA in 134 exposed workers and 53 nonexposed workers for evaluating the effect of ALDH2 polymorphism on toluene metabolism and urinary hippuric acid concentration as biological exposure indices (BEI) of toluene. The results were as follows; 1. The percentage of inactive genotype of ALDH2 in exposed workers was lower than that of exposed (P=0.081). 2. The percentages of exposed workers with inactive genotype did not have any significant difference by the increase of toluene exposure level or work duration. 3. The frequency of drinking, monthly and maximum amount of alcohol intake in workers with normal genotype were significantly higher than those with inactive genotype. 4. The urinary hippuric acid concentration of nonexposed workers ,with inactive genotype was significantly lower than that with normal genotype. Under 100 ppm of toluene, similar but statistically insignificant trends were found, while above that concentration of toluene, reverse but statistically insignificant trends were found. 5. The number of acute and chronic subjective symptoms were increased positively with the concentration of toluene in workers with normal genotype, but ho such trends were found in workers with inactive genotype. 6. The result of simple linear regression between toluene and urinary hippuric acid concentrations showed a very significant positive linear relation-ship. The mean hippuric acid concentration of nonoccupational exposure was 0.289+/-0.227 (0.062-0.516) g/l. Toluene exposure level unable to discriminate with nonoccupational exposure estimated from regression equation, it range from 7.29 to 9.87 ppm. Considering above all things, it was useful to estimate the exposure level of toluene by means of analysing urinary hippuric acid concentration in both genotype workers, but the biological exposure indices (BEI) of both genotypes were different from each other. The BEI of the total exposed workers was 2.76 g/ I, which was lower than current criteria 3.0g/ I (2.5 g/g Cr), and it also suggest that the BEI for the exposed workers in our country be lowered to the appropriate level after further study.

The Relationship between Noise Exposure Level in Worksite and Workers' Stress symptoms / 예방의학회지

Health services on industrial noisy environment have been provided only for noise-induced hearing loss management until now. But gradually, modern diseases and death have come to be related to stress and mental health deeply, therefore noise-induced mental disorder, like a stress became very important. In this point, the purpose of this study was to analyze the relationship between noise exposure level in worksite and workers' stress symptoms. This study included a survey of 786 manual workers selected from 89 worksites in 21 factories in Puchon. The results were as follows: 1. For demographic characteristics, most of the workers were males(80.8%), the 20~29 years old were 34.5% and those who graduated from high school were 65.3%. The workers whose monthly income ranged from 500,000 to 800,000 won were 37.5% and who have a religion were 47.9%. 2. For occupational characteristics, workers who had worked 1~5 years in the factories were 33.0%. Those who felt much for them workload were 43.9% and who worked more than 8 hours a day were 73.9 %. Those who were dissatisfied with their job and pay were 31.9% and 50.6%. The workers who responded ventilation condition of their worksites were bad were 51.9% and the dissatisfied with working environment of their wofksites were 45.9%. 3. Workers who were suffering from tinnitus were 53.3% and those who perceived hearing loss were 50.l%. Persons who reported they always wore earplugs at work were 35.4%. Those who felt earplugs bigger than their ears were 30.6% and those who experienced eardiseases caused by earplugs were 25.6%. 4. For the noise exposure level in worksite, workers who were exposed to 80-90dB were 30.3%, 90-100dB were 26.4% and 50~70dB were 19.2%. 5. workers' stress symptoms were significantly related to marital status and their monthly income p< 0.05). Workers who were single and had lower monthly income showed higher PSl (Psychiatric symptom Index) scores than those who were married and had higher monthly income. Higher PSl scores were also significantly related to l~2 days night-work per week, much for them workload, dissatisfaction with their job, and bad relationship with their bosses and coworkers. 6. Higher PSl scores were significantly related to severe tinnitus and perceived hearing loss p<0.001). Workers who felt the earplugs they use did not fit their ears showed significantly higher PSl scores(p<0.01). Workers who reported that they did not feel they need earplugs showed significantly higher PSl scores(p<0.05). Increased experience of eardisease caused by earplugs that did not fit were also significantly related to higher PSl scores(p<0.001). 7. The higher noise exposure level in worksite from 80dB was, the more severe stress symptoms including PSl subparts were reported; Anxiety, Anger, Depression, and cognitive disorder(p<0.001). 8. According to the results of stepwise multiple regression analysis, factors affecting workers' PSl scores were perceived hearing loss(R2=0.160), noise exposure level jn worksite(R2=0.110), relationship with coworkers, amount of workload, monthly income and relationship with bosses orderly and the total R2 of this 6 factors was 0.371. 9. The most significant factors that have impact on manual workers' stress symptoms were perceived hearing loss and noise exposure level in worksite, especially noise exposure level in the worksite was the most affective factor on the depression symptom.

Development of Methods to Estimate Exposure Levels to Vinyl Chloride Monomer and Multiphasic Screening Tests for Workers of Polyvinyl Chloride Manufacturing Factories / 대한산업의학회지

In order to develop questionnaire estimating vinyl chloride monomer(VCM) exposure levels, to reset selection criteria for detailed tests, to measure current VCM exposure levels, to evaluate the mutagenic effects of VCM exposures and to develop multiphasic screening method of PVC- or VCM-handling workers, VCM concentrations of work environments were measured and tentative self-administrative questionnaire, physical examination, sister chromatid exchange(SCE) test and some clinical chemical test were applied to 195 men who had been handling VCM or PVC(Exposed Group) and 37, in the same factories without exposure to VCM or in polyethylene- or polypropylene-related factories(Control Group). Mean VCM concentrations of work environments were 0.268+/-0.183 ppm under PVC synthesis processes, 0.160+/-0.200 ppm under VCM synthesis process, 0.076+/-0.111 ppm under PVC pipe producing processes, 0.090+/-0.108 ppm under PVC wall paper, sheet, or film producing processes, 0.071+/-0.051 ppm under PVC floor producing processes, 0.243+/-0.250 ppm under PVC sash producing processes, and 0.020+/-0.031 ppm under triming process. VCM levels of work environments under manual resin mixing processes (0.209+/-0.168 ppm)were higher than those of the others (0.209+/-0.168 ppm) (p-value0.05). SCE frequencies of the Exposed Group were significantly higher than those of Contorl Group(p-value<0.05) and those of test-abnormal persons were higher than those of test-normal persons. SCE frequencies linearly increased with not only current but also cumulative VCM exposure levels(p-value<0.05). These results suggest that adverse health effect may ensue from VCM exposure to as low as 1 ppm. But SCE frequencies had no statistically significant correlation with drinking amounts, smoking amoutns, or radiation dose equivalents. Questionnaire was revised by referring to these results and formula estimating cumulative VCM exposure levels based on occupational history in questionnaire were made. In addition, were presented methods evaluating work environments and multiphasic screening test for PVC workers.