Application of Geographic Information Systems (GIS) to Analyse and Detect the Risk of Chronic Diseases in the Elderly.

The prevalence of Non-Communicable Diseases (NCDs) in older people has been concerning in several ways. This study investigated the risks of health behaviour of elderly by applying the Geographic Information System (GIS) to analyse the risk of NCDs for the elderly in Thailand. METHODS: The survey investigated 1,006 elderly people in Chuen Chom District, Maha-Sarakham Province, Thailand. Kernel Density Estimation Surface was used for spatial analysis with 120 elderly by structured interviews concerning health behaviour to identify the risk of NCDs. RESULTS: It was found that in Lhao Dok Mai many elderly people had NCDs. The behaviour of the elderly creating risks of NCDs was drinking alcohol, smoking, lack of exercise, consuming excessive food, and stress. CONCLUSION: The risk areas for NCDs among the elderly were identified by GIS, therefore, local authorities should be supporting the elderly by using GIS to prevent any further severe cases of NCDs.

Paraquat exposure of backpack sprayers in agricultural area in Thailand.

Thai agriculturists heavily used paraquat in agricultural areas to control weed and grasses. This study determined paraquat exposure among backpack sprayers in Thailand and identified determinants of occupational exposure. Breathing zone air and dermal samples were collected from 57 backpack sprayers while spraying. Spot urine samples were collected on the day before spraying, end of spraying event and the next day after spraying. The subjects were interviewed about general demographics, agricultural activities, pesticide application and personal protective equipment used while applying paraquat. Paraquat concentrations in urine samples, air samples and dermal samples were determined by HPLC with a fluorescence detector. The median IQR of urinary paraquat concentrations on the day before spraying, end of spraying event, the next day after spraying were 2.51 (0.81-5.59), 8.23 (3.3-13.73) and 3.48 (1.03-8.19) µg/g creatinine, respectively. Concentrations of air samples and total dermal exposures were 5.15 (2.28-10.12) µg/m3and 92.66 (34.37-1647.46) µg/hr, respectively. Use of battery powered backpack sprayer and standing upwind effectively reduced inhalation exposures. Wearing a long sleeve shirt, long pants, boots, latex gloves and balaclava could reduce paraquat concentration on dermal exposure among backpack sprayers.

Evaluation of Dermal Exposure to the Herbicide Alachlor Among Vegetable Farmers in Thailand.

Vegetable farmers applying the herbicide alachlor may be highly exposed through dermal contact when spraying. Dermal patches were attached to 10 locations on the farmers' skin when they mixed and applied alachlor in vegetable farming areas in Thailand. Measurements were made on farmers using either a backpack sprayer with a 2 stroke gasoline motor and fan or a battery operated pump. Forty-seven vegetable farmers in Bungphra subdistrict of Thailand participated in this study. Both motorized and battery pump backpack sprayers wearing long-sleeve shirts had significantly lower alachlor concentrations on the dermal patches under their long-sleeve shirts compared to those who wore only short-sleeve shirts, regardless of the sprayer type. Moreover, sprayers wearing long pants had significantly lower alachlor concentrations on dermal patches placed under the pants on the lower legs than those wearing short pants, regardless of the sprayer type. The highest estimated alachlor exposures were found on the upper legs (median = 9.29 µg/h) for those using a 2 stroke engine/fan backpack sprayer and on the lower legs (2.87 µg/h) for those using the battery operated pump backpack sprayer. The estimated total body alachlor exposures of applicators using the 2 stroke engine/fan backpack sprayer (219.48 µg/h) were significantly higher than those using the battery operated pump backpack sprayer (15.50 µg/h). Using long-sleeve shirts as personal protection reduced alachlor exposures for the arms 97-99% and wearing long pants reduced alachlor exposure to the legs for 81-99%. Thus, training about the protection provided by clothing choices would be one step in improving the health and safety of Thai farmers.

Paraquat Exposure of Pregnant Women and Neonates in Agricultural Areas in Thailand.

This study aimed to assess paraquat concentrations in the urine of women at 28 weeks of pregnancy, delivery and 2 months postpartum and in the meconium of neonates. In all, 79 pregnant women were recruited from three hospitals located in agricultural areas in Thailand. The subjects were interviewed about personal characteristics, agricultural activities and pesticide use patterns. Paraquat was analyzed in urine and meconium using high performance liquid chromatography equipped with a fluorescence detector. The geometric mean (GSD) of urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum were 2.04 (4.22), 2.06 (5.04) and 2.42 (5.33) ng/mL, respectively. The urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum between agriculturist and non-agriculturist were not significantly different (p = 0.632, p = 0.915, p = 0.57 respectively). The geometric mean (GSD) of paraquat concentration in the meconium was 33.31 (4.59) ng/g. The factors predicting paraquat exposures among pregnant women and neonates included working outside, living near farmland, having family members who work on a farm, drinking well water and using herbicides or paraquat.

EXPOSURE TO EXTREMELY LOW FREQUENCY ELECTROMAGNETIC FIELDS DURING LESSONS IN SECONDARY SCHOOLS.

Schools are a significant location where children are exposed to electromagnetic fields (EMFs), which may cause adverse health effects. This cross-sectional study aimed to examine exposure levels to extremely low frequency magnetic fields (ELF-MFs) with a range of 5 Hz-32 kHz, and ELF-electric fields (ELF-EFs) with a range of 5 Hz-2 kHz in secondary schools in Bangkok, Thailand. This study was conducted in 60 classrooms from three schools during class hours. Spot measurements were taken with a Narda EFA 300 field analyzer to evaluate exposure levels. This study showed that ELF-EMF exposure levels are lower than ICNIRP guidelines, while 21.67% of classrooms had a magnetic field strength above 0.2 µT, and the main sources of ELF-EMFs were electrical equipment and electrical wiring. Future studies should measure ELF-EMF levels in other areas and evaluate the effects of long term exposure to ELF-EMFs on children's health.

Health effects of people living close to a petrochemical industrial estate in Thailand.

OBJECTIVE: An acute health effect of people living near the petrochemical industrial estate in Thailand was assessed using a panel study design. MATERIAL AND METHOD: The populations in communities near the petrochemical industrial estates were recruited. The daily air pollutant concentrations, daily percentage of respiratory and other health symptoms reported were collected for 63 days. The effect of air pollutants to reported symptoms of people were estimated by adjusted odds ratios and 95% confidence interval using binary logistic regression. RESULTS: The significant associations were found with the adjusted odds ratios of 38.01 for wheezing, 18.63 for shortness of breath, 4.30 for eye irritation and 3.58 for dizziness for total volatile organic compounds (Total VOCs). The adjusted odds ratio for carbon monoxide (CO2) was 7.71 for cough, 4.55 for eye irritation and 3.53 for weakness and the adjusted odds ratio for ozone (O3) was 1.02 for nose congestion, sore throat and 1.05 for phlegm. CONCLUSION: The results showed that the people living near petrochemical industrial estate had acute adverse health effects, shortness of breath, eye irritation, dizziness, cough, nose congestion, sore throat, phlegm and weakness from exposure to industrial air pollutants.

Health risk assessment of volatile organic compounds in a high risk group surrounding Map Ta Phut industrial estate, Rayong Province.

OBJECTIVE: The health risks of a high-risk group, surrounding Map Ta Phut industrial estate, Rayong, which may be exposed to VOCs through inhalation of contaminated air and dermal contact of contaminated water were assessed. MATERIAL AND METHOD: The health risk was assessed for 19 subjects categorized as children, adult and elderly from Ban plong and Nongfab communities following the US Environmental Protection Agency (EPA) method. The VOC concentrations in ambient air and ground water were monitored by Pollution Control Department (PCD), Ministry of Natural Resources and Environment to represent average VOC exposure of subjects. RESULTS: The lifetime cancer risk of VOCs exposure from inhalation and dermal contact with ground water were 1.32 x 10(-7)-5.21 x 10(6) for elderly 1.18 x 10(-7)-6.20 x 10(-6)for adult and 8.93 x 10(-7)-5.93 x 10(-6) for children. For non-cancer risk, the hazard index was 0.44 for elderly, 0.38-0.42 for adult and 0.55 for children. CONCLUSION: The lifetime cancer risk of the high-risk group living near Map Ta Phut industrial estate was in acceptable range for elderly, adult and children. For non-cancer risk, it is also acceptable.

Assessment of occupational exposure to malathion and bifenthrin in mosquito control sprayers through dermal contact.

OBJECTIVE: To assess occupational exposure of malathion and bifenthrin concentrations by dermal contact and urinary 3-(2-chloro-3, 3, 3-trifluoro-1-propenyl)-2, 2-dimethyl-cyclopropanecarboxylic (TFP) acid, health symptoms developed and the relationship between bifenthrin concentrations and TFP acid in urine of the mosquito control sprayers. MATERIAL AND METHOD: The aerosols of these two pesticides were collected using 100 cm2 cotton patches attached on the skin of upper legs of 54 volunteer of mosquito control sprayers. Their urine samples were also collected before and after application. RESULTS: These subjects exposed to average malathion and bifenthrin concentrations of 0.18 and 0.32 microg/cm2, respectively After application, the average concentration of urinary TFP acid in the sprayers was 39.22 +/- 0.77 mg/g creatinine ranging from 0.58 to 261.19 mg/g creatinine. A significant difference was found between urinary TFP acid levels before and after application (p < 0.001) but the bifenthrin concentrations through dermal contact and urinary TFP acid levels were not significantly correlated (p > 0.05). CONCLUSION: The mosquito control sprayers had dermal contact with smoke of malathion and bifenthrin and some sprayers developed health symptoms after exposure. They should use protective clothing made ofplastic, nylon or polyester to protect sprayers from skin contact.

Exposure to trinitrotoluene and health effects among workers in an artillery and ammunition plant.

OBJECTIVE: To determine urinary trinitrotoluene (TNT), 2-amino-4, 6-dinitrotoluene (2ADNT) and 4-amino-2, 6-dinitrotoluene (4ADNT) and health effects upon workers in an ammunition plant. MATERIAL AND METHOD: The urine samples from forty munition workers and forty office workers were monitored for TNT and its metabolites by gas chromatography-mass spectrometry. The workers were interviewed with a questionnaire. RESULTS: The median levels of TNT and its metabolites were 112.84 and ranged from non-detectable (ND) to 1,833.81 mg/L. Median levels for 2ADNT were 11.66, ranging from ND to 360.89 mg/L. Median levels for 4ADNT were 19.95 and ranged from ND to 314.28 mg/L. There were significant correlations between TNT and 2ADNT in urine (r = 0. 700, p-value < 0.001), as well as for TNT and 4ADNT (r = 0.783, p-value < 0.001). Exposed workers reported eye, nose and throat irritations, weakness and headaches with considerably higher frequency than non-exposed workers. CONCLUSION: TNT levels in urine were strongly associated with 4ADNT and 2ADNT levels. Workers exposed to TNT complained of nose, throat and eye irritation, along with overall weakness and headaches.

Exposure to particulate matter, CO2, CO, VOCs among bus drivers in Bangkok.

OBJECTIVE: To measure the exposure of particulate matter CO2, CO, VOCs among Bangkok Mass Transit Authority (BMTA) Bus Drivers. MATERIAL AND METHOD: The exposure of 60 bus drivers to PM2.5, PM10, VOCs, CO2, CO was monitored for full shifts on three routes of air-conditioned (A/C) and non-A/C buses. RESULTS: The average PM2.5 exposure concentrations among non-A/C bus drivers (323.81 mg/m3) were significantly higher than that of A/C bus drivers (206.46 mg/m3) (p-value = 0.016). The average benzene, toluene and xylene exposure concentrations were 429.15, 225.11, 127.60 mg/m for non-A/C bus drivers. The average CO2 levels in A/C buses were significantly higher than those in non-A/C buses (p-value < 0.001). The CO levels in non-A/C buses were significantly higher than those in A/C buses (p-value = 0.037). CONCLUSION: The bus drivers were exposed to high concentrations of air pollutants. The increase of ventilation and cleaning of buses will reduce the exposure of air pollutants.

Ethion exposure and biological monitoring in vegetable farmers.

OBJECTIVE: To modify the method of analysis of urinary diethyl phosphate (DEP) in order to determine the relationship between atmospheric ethion concentration and urinary DEP concentration. MATERIALS AND METHOD: A cross-sectional study was conducted by collecting atmospheric ethion in the breathing zone of 28 farmers following the NIOSH 5600 method. Urine samples were also collected to analyze urinary DEP concentrations by a modified method using a Gas Chromatography-Flame Photometric Detector (FPD). RESULTS: The average atmospheric ethion concentration in the breathing zone of farmers was 0.036 +/- 0.018 mg/m3. The average urinary DEP in pre-shift and post-shift was 0.030 +/- 0.06 and 0.851 +/- 1.80 mg/g of creatinine respectively. The average DEP during work shifts was 0.53 +/- 0.27, and ranged from 0.12 to 1.16 mg/g of creatinine. A high correlation coefficient (r = 0.645) was found between atmospheric ethion concentrations and urinary DEP concentrations at p < 0.001. CONCLUSION: The modified method provided a reliable result and the urinary DEP during work shifts was found to be a reliable biomarker of ethion exposure.

Development of an airborne lead analysis kit and its application.

We developed a method to analyze airborne lead concentrations in the field. It was a modification of the colorimetric method using the reaction between 4(2-pyridylazo)-resorcinol (PAR) and lead with cyanex302 in an acid medium to reduce interfering metals. The lead concentration was detected with a photometer made in Thailand. The developed method uses an impinger containing 1% nitric acid solution as an absorbing agent to collect airborne lead at a flow rate of less than or equal to one liter/minute. Cyanex302 solution in toluene was used to extract metals from the samples and 0.1M nitric acid was used to extract just lead. The lead solution was reacted in 0.5 ml of 0.03% PAR solution, with 1 ml ammonium chloride buffer; the absorption of this solution was measured by a photometer. The results show the limit of detection (LOD) was 0.01 mg/l. The limit of quantification (LOQ) was 0.03 mg/l. The percent recovery of the lead concentrations of 0.05 - 3.0 mg/l was 94.0 to 103.5%. The precision presented as %CV ranged from 0.65 to 10.27%. Lead concentration in a lead smelting factory detected by this method was not significantly different from that detected by the NIOSH method: 7,303 at a 95% confidence level.

Design and development of ultraviolet germicidal irradiation device for controlling airborne bacteria in the workplace.

OBJECTIVE: To design and develop an ultraviolet germicidal irradiation (UVGI) device for controlling airborne bacteria in the workplace of hospitals. MATERIAL AND METHOD: The constructed UVGI device was a chamber, consisting of a return air grille, an air supply grille, two 30-watt ultraviolet lamps and a cross flow fan inside the chamber. The efficiency of the UVGI device was tested at three different flow rates of 15.7, 31.6 and 46.1 m3/min, respectively by collecting bacteria samples before and after operating the device for 30, 60, 90 and 120 minutes. RESULTS: The efficiency of the UVGI device at flow rates of 15.7, 31.6 and 46.1 m3/min was 60.6, 92.8 and 80.8%, respectively and the bacteria concentration was reduced to less than 100 cfu/m3, except at the flow rate of 15.7 m3/min. The application of the UVGI device in the specimen-received room showed that the concentration of bacteria was reduced to less than 100 cfu/m3 after 180 minutes. CONCLUSION: The constructed UVGI device was effective to reduce airborne bacteria in workplace of hospital.

Assessment of nicotine inhalation exposure and urinary cotinine of tobacco processing workers.

OBJECTIVE: To study the composition of tobacco dust, atmospheric nicotine concentration, urinary cotinine excretion and the subjective symptoms of workers in dry tobacco leaf preparation. MATERIAL AND METHOD: The tobacco dust in air of the breathing zone of workers and the urine samples of these workers and a comparison group were collected and analyzed by GC/MS. The accuracy, precision and detection limit of the methods were determined. RESULTS: The tobacco dust contained nicotine and atrazine (a herbicide). The average atmospheric nicotine was 0.105 mg/m3 and urinary cotinine concentrations of post tobacco curing process workers was 3.084 microgram/ml. Moreover, there was a significant correlation between the atmospheric nicotine dust and urinary cotinine excretion (r = 0.987, p < 0.05). The health symptoms of headache, nausea, weakness, dizziness, and increased perspiration reported among workers had a significant relationship with the job characteristics of the post tobacco curing process workers, with a p-value < 0.05. CONCLUSION: Nicotine dust contained a herbicide called atrazine. Nicotine concentrations were highest in the post tobacco curing process where workers reported a lot of adverse symptoms. Urinary cotinine can be used as a biomarker of tobacco dusts' exposure in dry tobacco leave preparation areas.

Assessment of nicotine dermal contact and urinary cotinine of tobacco processing workers.

OBJECTIVE: To assess the dermal contact of nicotine dust, subjective symptoms and urinary cotinine of post curing tobacco workers. MATERIAL AND METHOD: Dermal hand wipes of residual nicotine dust samples, morning urine samples and subjective symptoms were collected from 30 workers. The hand-wipe samples and urine samples were analyzed for nicotine and cotinine by a GC/MS, respectively. RESULTS: The average amount of nicotine on the hands of workers was 0.24 microgram/cm2, while the average urinary cotinine concentration of workers was 3.08 microgram/ml. Moreover, there was a significant correlation between nicotine residue on hands and urinary cotinine excretion at r = 0.978, p < 0.05. There was also a significant relationship between the occupational related nicotine residue on hands and the number of subjective symptoms reported (p < 0.05). CONCLUSION: The nicotine residue on hands could be used as an indicator of occupational nicotine dust exposure which might affect the health of tobacco workers.

High performance liquid chromatography for determination of urinary metabolites of toluene, xylene and styrene and its application.

The purpose of this research was to determine mandelic, phenylglyoxylic, hippuric, o-, m- and p-methylhippuric acids, the six urinary metabolites of styrene, toluene and xylene by high performance liquid chromatography (HPLC). These metabolites were extracted in an acid medium, transferred into a basic solution and back extracted again using ethyl acetate, and the organic phase was evaporated to dryness under a compressed air flow at room temperature. The residue obtained was dissolved in 1 ml mobile phase solution of 0.01 M potassium orthophosphate in 0.3% acetic acid (adjusted to a pH of 2.5 with orthophosphoric acid):tetrahydrofuran:acetonitrile(87:5:8) and 100 microl was injected into a HPLC equipped with a 4.6 x 250 mm ODS3-C18 reversed phased column and ultraviolet (UV) detector at a wavelength of 254 nm. All metabolites were clearly separated within 21 minutes. The detection limits of the method were 1.1 ng/ml for PGA, 4.9 ng/ml for HA, 17.0 ng/ml for MA, 2.5 ng/ml for o-MHA, 1.7 ng/ml for p-MHA and 2.0 ng/ml for m-MHA. The percent recoveries of the six metabolites were 99.2-101.8% with percent coefficients of variation of less than 2%. The method was applied to the analysis of urine samples of twelve workers exposed to toluene, xylene and styrene in a paint factory. The 5-day post-shift urinary excretions of the six metabolites in these workers are presented. The metabolites were found at levels greater than the Biological Exposure Index (BEI) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).

Development of a sampling and analysis method for 4-vinyl-1-cyclohexene in air.

The purpose of this research was to develop an applicable sampling and analytical method to determine airborne 4-vinyl-1-cyclohexene concentrations which are usually found in the atmosphere of polybutadiene factories. A solid sorbent tube, containing two sections (100 mg in the front and 50 mg in the back) of activated coconut-shell charcoal was chosen for sampling 4-vinyl-1-cyclohexene vapor. The 4-vinyl-1-cyclohexene in the charcoal samples was desorbed with carbon disulfide and analyzed by gas chromatography equipped with a flame ionization detector. The suitable air flow rate, adsorption capacity, sample storage stability, desorption efficiency and reliability of the method for sampling and analysis of 4-vinyl-1-cyclohexene were evaluated. The method was applied to sampling and analysis of 4-vinyl-1-cyclohexene in the rubber industry. The results indicated a suitable air flow rate of 0.3 to 1.5 l/min. The adsorption capacity of 4-vinyl-1-cyclohexene on 100 mg of charcoal was 0.2134 mg. The 4-vinyl-1-cyclohexene adsorbed on the charcoal was stable for 7 d at room temperature or 21 d in a refrigerated condition. The average percent desorption efficiency of 4-vinyl-1-cyclohexene ranged from 90.45% to 97.04% with the loaded amount ranging from 0.412 to 8.250 microg using 1 ml carbon disulfide. The limit of detection of 4-vinyl-1-cyclohexene was 0.044 ng. The average percent recoveries (n=6) of 4-vinyl-1-cyclohexene adsorbed on charcoal ranging from 0.46 to 8.87 microg were 96.78-102.87% with relative standard deviations (RSDs) of 0.34-1.92%, respectively. The concentrations of 4-vinyl-1-cyclohexene ranged from 0.011 to 0.105 mg/m(3) in the working environment of a polybutadiene factory.