Wantanee Phanprasit

Respiratory and skin effects of exposure to wood dust from the rubber tree Hevea brasiliensis

Objectives: Potential health effects related to wood dust from the rubber tree, which produces natural rubber latex, have not been previously investigated. The main aim of this study was to investigate the relations of rubber tree dust exposure to respiratory and skin symptoms, asthma and lung function. Methods: A cross-sectional study was conducted among 103 workers (response rate 89%) in a rubber tree furniture factory and 76 office workers (73%) in four factories in Thailand. All participants answered a questionnaire and performed spirometry. Inhalable dust levels were measured in different work areas. Results: Factory workers showed increased risk of wheezing, nasal symptoms and asthma compared to office workers. There was a dose-dependent increase in wheeze and skin symptoms in relation to dust level. Significantly increased risks of nasal symptoms (adj OR 3.67, 95% CI 1.45 to 9.28) and asthma (8.41, 1.06 to 66.60) were detected in the low exposure category. Workers exposed to ethyl cyanoacrylate glue had significantly increased risk of cough, breathlessness and nasal symptoms. There was dose-dependent reduction in spirometric lung function with wood dust level. Conclusions: This study provides new evidence that workers exposed to wood dust from the rubber tree experience increased risk of nasal symptoms, wheeze, asthma and skin symptoms and have reduced spirometric lung function. Exposure to cyanoacrylate is related to significantly increased respiratory symptoms. Results suggest that the furniture industry using rubber tree wood should implement appropriate exposure control measures to reduce wood dust exposure and cyanoacrylate glue exposure to protect their employees.

Respiratory effects of occupational exposures in a milk powder factory

Ingestion of milk powder is a known cause of allergies in children, but the risks to respiratory health from exposure to inhaled milk powder have not been studied previously. The aim of the present study was to assess the effects of occupational exposures in a milk powder factory on respiratory symptoms and lung function. A cross-sectional study was conducted on 167 milk powder factory workers (response rate 77%) and 76 office workers (73%) from four factories in Thailand. All participants answered a questionnaire and performed spirometry. Measurements of concentrations of dust were used to give additional information on exposures. Mean respirable dust concentrations in the factory were 0.02–2.18 mg·m−3. The risk of breathlessness and nasal symptoms were significantly increased in production and packing staff. The risk of skin symptoms was significantly increased in those adding vitamin mixture to milk powder. Factory workers showed significantly lower forced expiratory volume in one second measured as percentage of predicted value. The present study provides new evidence that workers exposed to milk powder by inhalation are at an increased risk of nasal symptoms, wheezing and breathlessness, and exhibit reduced spirometric lung function, even at relatively low air concentrations of milk dust.

Asbestos Exposure among Mitering Workers

The objectives are to compare the airborne asbestos concentrations resulted from mitering of abestos cement roof sheets by a high-speed motor and a hand saw, and to monitor whether other workers near the test sites are vulnerable to the fibers exceeding the occupational exposure limit. Four test cases were carried out and altogether 7 personal and 4 area air samples were collected. The NIOSH method 7400 was employed for the air samplings and analysis. Using the phase contrast microscopy, fiber counting was conducted under Rule A. The study showed that the fiber concentration medians for personal air samples gathered from the two tools were 4.11 fibers/cc (ranged: 1.33-12.41 fibers/cc) and 0.13 fibers/cc (ranged: 0.01-5.00 fibers/cc) respectively. The median for the area samples was 0.59 fibers/cc (ranged: 0.14-3.32 fibers/cc). Comparing each study case, the concentration level caused by the high-speed motor saw was more than twice that of the hand saw. According to the area samples, the workers nearby the test site are at risk from high exposure to asbestos.

51 Global warming and occupational heat and hot environment standard in thailand

Introduction The current occupational exposure to heat and hot environment standard of Thai law was issued in 2006. The wet bulb globe temperature (WBGT) index was defined for 3 workload levels without a work-rest regimen. To assess heat exposure according to the law, workload and WBGT is monitored for 2 hours during the hottest period of the day in summer. As has been predicted, global warming could significantly impact labour capacity and productivity in Southeast Asian countries. Thus, this study aimed to explore whether the occupational standard could protect outside workers focusing on construction workers in Thailand. Methods This cross-sectional study included 18 medium and small construction sites and involved 90 heat acclimatised construction workers. Most wore cotton long sleeve shirts and pants. Heart rate (HR) and Aural (tympanic) temperature of the participants were recorded continuously for 2 hours. Exposure data comprised relative humidity, wind velocity and WBGT, including dry bulb, wet bulb and globe temperatures, were monitored and the participants’ workloads were estimated, simultaneously with the collection of physiological and environmental data, i.e. March to June. In addition a questionnaire was used to collect data of the participants. Result WBGT ranged from 24.35–34.18°C, and 47 participants were exposed to WBGT exceeding the standard. Average air velocity and RH were 1.11 m/s and 35.77%, respectively. The range of average core body temperature and HR for 3 levels of workload were 36.60–39.4°C, 70–97 bpm, 36.62–39.58°C, 80–126 bpm and 37.04–40.08°C, 82–127 bpm respectively. Core body temperature of 29 of 47 participants exposed to heat above the standard exceeded 38°C, among these 11 had symptoms of heat related illness. In all, 18 participants were exposed to heat below the standard but their core body temperatures were higher than 38°C. Discussion The weather was hot and dry with occasional good air movement. However, 32% of construction workers worked in high risk conditions (WBGT above the standard). Furthermore, 18 (20%) participants worked in an environment below the standard but their body core temperatures exceeded 38°C. Thus, this group of workers was not protected by the standard.

Mercury health risk assessment among petrochemical workers in Rayong Province, Thailand

ABSTRACT Background: Mercury occurs naturally in environment; thus, retention of fossil fuels used as feedstock in petrochemical plants is commonly found. The purpose of this study was to assess mercury health risks among petrochemical workers. Methods: In all, 188 operators and 30 office workers were recruited from 3 petrochemical plants. A total of 83 and 56 air samples were collected during normal working days and turnaround (TA) periods, respectively. Three main meals over 5 consecutive days, drinking water and spot urine samples were collected. Demographics and lifestyle data were collected using questionnaires. USEPA guidelines for mercury health risks were applied. Results: The inhalation exposure during normal working days of the two groups was lower than 5% of the Threshold Limit Value (TLV), but during TA some operators’ exposure exceeded the TLV. The average urinary mercury concentrations of the two groups did not significantly differ. The mercury concentration in the water samples was undetected and did not differ in the food samples of the two groups. Sixty-six operators presented a hazard quotient, HQinh greater than 0.2, but none of office staff, and 98 of 218 participants had hazard index, HI >1. Conclusion: Unacceptable mercury health risk among the petrochemical worker mostly cause by mercury in cooked food.

0478 Inhalation and dermal exposure to toluene among printing workers in a plastic bag factory

Introduction The study was conducted in a plastic bag factory to explore the inhalation and dermal exposure to toluene of the printing workers who wore no PPE and the potential of a charcoal cloth pad (CCP) as a dermal sampler to assess the skin permeation of liquid toluene. Methods Twenty-seven stationary air samples were collected on the same 9 days with the urine and dermal samples from 11 printing workers. The CCPs were wrapped on each of the workers’ fingers. Air samples were collected and analysed according to NIOSH # 1501 and 65 post-shift urine samples were collected and analysed for toluene using GC-HS/FID. Multiple linear regression was employed to analyse the association of the variables. Result T three urine samples contained toluene exceeding the BEI of 30 mg/L. Toluene on the CCP (TolCCP) is a meaningful predictor for the UTol (p-value=0.027), with r and r2 of 0.441 and 0.195 respectively. The absorbed dose of toluene determined from TolCCP ranging in between 1.05–91.94 mg and counting for the maximum of 12.3% TLV. Discussion The mean of TWA was above the TLV while that of the UTol was well below the BEI. This indicated that the TWA concentrations could be overestimated due to the size of the room and good general ventilation. The dermal exposure was not significant if the workers wear respirators, but if not the dermal absorption could contribute to the overall uptake and may cause the exposure above the TLV.

Case study of occupational mercury exposure during decontamination of turnaround in refinery plant

Abstract Decontamination during turnaround (TA) can lead to high exposure to toxic chemicals among workers. The decontamination process in refinery plants usually comprises two types, i.e. steam and chemical decontamination. No matter the method used, concentrations of toxic chemicals must be measured using the direct reading instrument at the end of each decontamination cycle, which maybe repeated several times until the readings are in acceptable level. To evaluate mercury exposure of decontamination workers during decontamination procedure in comprehensive turnaround of a refinery plant. Thirty personal and 16 area air samples were collected using passive dosimeters and absorbent tubes, respectively, during 8 days of the decontamination in comprehensive turnaround. All samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Good practices and standard procedures for air sampling and analysis were performed. The TWA concentrations were calculated and compared between steam and chemical decontamination workers. All area samples were well below TLV (ND – 0.0016 mg/m3) while 5 of 14 samples collected at the steam team and 1 of 16 samples taken from the chemical team exceeded the TLV. The geometric mean (GSD) of TWA concentration of the steam team was 0.0057(10.4906) mg/m3, which is about twice as high as that of the chemical team, 0.0031(6.9422) mg/m3. The highest mercury concentration, 0.1037 mg/m3, was collected from a steam decontamination worker. According to the activities and observation, the steam team may have high exposure while reading the chemical concentrations at the end of the decontamination cycle.

Respiratory and skin health among glass microfiber production workers: a cross-sectional study

Objectives A few studies have investigated non-malignant respiratory effects of glass microfibers and these have provided inconsistent results. Our objective was to assess the effects of exposure to glass microfibers on respiratory and skin symptoms, asthma and lung function. Methods A cross-sectional study of 102 workers from a microfiber factory (response rate 100%) and 76 office workers (73%) from four factories in Thailand was conducted. They answered a questionnaire on respiratory health, occupational exposures, and lifestyle factors, and performed spirometry. Measurements of respirable dust were available from 2004 and 2005. Results Workers exposed to glass microfibers experienced increased risk of cough (adjusted OR 2.04), wheezing (adjOR 2.20), breathlessness (adjOR 4.46), nasal (adjOR 2.13) and skin symptoms (adjOR 3.89) and ever asthma (adjOR 3.51), the risks of breathlessness (95% CI 1.68 to 11.86) and skin symptoms (1.70 to –8.90) remaining statistically significant after adjustment for confounders. There was an exposure-response relation between the risk of breathlessness and skin symptoms and increasing level of microfiber exposure. Workers exposed to sensitising chemicals, including phenol-formaldehyde resin, experienced increased risk of cough (3.43, 1.20 to 9.87) and nasal symptoms (3.07, 1.05 to 9.00). Conclusions This study provides evidence that exposure to glass microfibers increases the risk of respiratory and skin symptoms, and has an exposure-response relation with breathlessness and skin symptoms. Exposure to sensitising chemicals increased the risk of cough and nasal symptoms. The results suggest that occupational exposure to glass microfibers is related to non-malignant adverse health effects, and that implementing exposure control measures in these industries could protect the health of employees.