การประเมินการสัมผัสสารอินทรีย์ระเหย (เบนซีน โทลูอีน เอธิลเบนซีน และไซลีน) ของประชาชนในชุมชนแออัดในกรุงเทพมหานคร : กรณีศึกษาชุมชนแออัดคลองเตย = Exposure assessment on volatile organic compounds (Benzene toluene ethylbenzene and xylene) among Bangkok slum people : a case study Klong-Toey community / วิทยาลัยวิทยาศาสตร์สาธารณสุข จุฬาลงกรณ์มหาวิทยาลัย
This study has applied both qualitative (e.g. in-dept interviews) and quantitative methods (e.g.surveys and a passive air sampler) The passive air sampler and survey was undertaken to collect airborne samples in order to analyze the concentration of benzene, Toluene, Ethylbenzene and Xylene (BTEX), while urine samplings were used to measure the level of Trans, Trans-Muconic acid of people living in the slum of Klong Toei, Bangkok. The objectives of this study include; 1. To measure the concentration level and average daily dose (ADD) received of Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) of target populations in the slum of Klong Toei, Bangkok 2. To asses health conditions of target populations exposed by BTEX 3. To examine relationships between the concentration of BTEX exposure and health problems of target populations 4. To use the result of this study to advocate communities and the government in establishing public policy for BTEX prevention and controls According to the survey (n=500), 91.6% were exposed to the BTEX, Volatile Organic Compounds (VOCs), and vehicle emissions because their houses were located less than 500 meters from the street. Apart from these, the insecticide, mosquito repellent, hair spray, air freshener and other volatilized, lacquer and glue were minor sources of BTEX exposure The average age of subjects was 48 years old, approximately living in the community for 30 years. 79.4% were female, 37.6% were a housewife and unemployed, 15.7% was a merchant and 14.2% was a daily worker. The average family income was 10,400 Bahts a month. The duration of BTEX exposure was 24 hours per day (69.9%), 7 days per week (98.9%). (In addition, the major of populations stayed in the community 24 hours a day (69.9%) and 7 day a week (98.9%). In term of the participants’ occupation, one-fifth of the participants had jobs that risk to the VOCs exposure. In addition, the study found that more than half of the participants exposed to the VOCs via the second hand smokers (family member and neighboring smoking) Eighty six subjects, who worked over 8 hours on the weekday, were selected for the personal air sampling and the urine sampling in 3 seasons. As a result, the average Toluene concentration in personal was relatively high compared with Xylene in 3 seasons. Meanwhile, the Benzene concentration was higher than Ethylbenzene in the rainy and the winter season, but it reverted in the summer. It also found that the concentration of Benzene, Ethylbenzene and Xylene of subjects (100%) was less than 10 ppb in each season. Two-third received Toluene rather high (>10 ppb) in the winter. For the level of trans, trans-muconic acid; the results indicated that it was less than the risky level. However, it was higher the safety standard level in the rainy season.
The results indicated that the Toluence’s average was highest in every season, followed by the Xylene. The major reason was related to the regularity of fire accidents in communities, making people to rebuild and repaint their house. Moreover, most of subjects used cleaning products and burned incenses every Buddhist day without ventilations. Thus, the subjects were exposed to both direct (e.g.house painting, incense’s smoke inhalation, and contacting with cleaning products) and indirect ways (neighbor’s activities). In comparison with three seasons, it found that there was no statistical significant on Toluene and Ethylbenzene, but there was statistical significant on Benzene and Xylene. It showed lower average in the summer season than other seasons, which related to the evaporation because of high temperature. In addition, the biomarker of Benzene (trans, trans-muconic acid; ttma) might be interfered by other derivatives such as food preservative’s derivatives. There was no relationship between health problems and the concentration of BTEX exposure among subjects. However, people perceived and realized the health problems caused by VOCs exposure. It might be house painting, using mosquito spray and lighting joss sticks everyday in communities. According to In-depth interviews, two-third has not satisfied living in their community, but nowhere else to live. One-third responded that they were not risky to BTEX exposure. One-third also perceived that they have health problems, but they did not know the causes. It showed that people lack knowledge and awareness towards risks and dangers of the BTEX exposure. The study suggested that the cooperation among communities, the governmental and non-governmental organizations would play important roles in preventing and controlling the BTEX exposure. In particular, it is necessary to involve community leaders, health volunteers, women groups and youth groups in order to make the cooperation become more effective.
