| 英文摘要 |
This is a second year investigation for the project: “Health surveillance for Yunlin school children exposed to river dust from the Choshui River.”The major purposes of this project are as follows: (1) assessment of the exposure of elementary school children to river-dust, (2) determination of the urinary levels of metal and 8-oxodG in children, (3) conducting the cardiopulmonary function test in children, (4) assessments of quality of life among children and adult residents, (5) estimation of required clinic visits for selected diseases among children and adult residents, and (6) health education intervention.
Three sampling periods were executed in this project. One river-dust episode occurred during the first sampling period. During the river-dust episode, the concentrations of PM10 and metals in the outdoors of the classrooms, indoors of the classrooms, and indoors of homes were all significantly higher at the exposure sites (Lunbei Township and Erlun Township) than the levels at the control sites (Gukeng Township and Linnei Township). The daily exposure doses of PM10 aerosols and metals during the river-dust episode were significantly higher at the exposure sites than those at control sites. For the exposure sites, the concentrations of PM10 and metals outdoors of the classes, indoors of the classes, and indoors of homes were all significantly higher during the river-dust episode than those during the non river-dust episodes. Four elements (Ca, Al, Fe ＆ Mg) were identified as the major elements in the river dust of the Choshui River. The concentrations of these four elements in PM10 aerosols showed significant increases during the river-dust episode. However, it is worth noting that the concentrations of toxic metals (As, Ni, Cr ＆ Co) in PM10 aerosols also increased during the river-dust episode.
Potential metals exposure via the dust ingestion pathway was evaluated. The results showed that for 8-hr exposure school children in the exposed areas had higher exposure doses of As, Cr(VI), Cd and Ni than did school children in the non-exposed areas. Because of the lack of 8-hr Reference Exposure Levels (RELs) of these metals, we have compared the exposure doses of As, Cr(VI), Cd and Ni observed with their corresponding Chronic RELs. The results showed that the exposure doses of As, Cr(VI), Cd and Ni obtained for school children in the exposed areas were far lower 102 times than the chronic RELs.
Urinary metal analysis showed that school children in the exposed areas had significantly higher urinary metal concentrations than did school children in the non-exposed areas during the river-dust period. School children in the exposed areas also showed higher urinary metal concentrations during the river-dust period than during the non river-dust period. Similarly, urinary 8-oxodG analysis revealed that school children in the exposed areas had significantly higher urinary 8-oxodG concentrations during the river-dust period than during the non-river-dust period. It was further noticed that urinary concentrations of Fe, As, Ni, Cu and V involved in the induction of oxidative stress, were significantly higher during the river-dust period than during the non-river-dust period.
By merging two datasets in terms of the Taiwan National Health Insurance Research Database and the PM10 data derived from the Lunbei air-quality monitoring station located at Yunlin County, the 10-year data (2002-2011) showed that there are significant dose-response effects between PM10 levels and clinical visits concerning chronic obstructive pulmonary disease and other diseases of the upper respiratory tract among children, implying that river dust may influence physical health (especially pulmonary diseases). Nevertheless, individuals living in low river-dust exposure areas were not superior to those living in high exposure areas on the assessments of quality of life and mental health, indicating a limited effect of river dust on psychological well-being.
After the health education intervention, we found that students in the experimental group had significantly higher scores on knowledge (both in short-term and long-term studies) than did those in the control group. Moreover, the river dust protective equipment installed both in the classroom and outside the classroom may have a long-term protective effect on children's lung function. Furthermore, the risk of lung function abnormalities in the students in the classroom "without protective equipment" were significantly higher than those in the classroom "with high use of protective equipment" in high exposure areas (OR=2.47, P=0.012).
|