Maharachpong Nipa, Geater Alan, Chongsuvivatwong Virasakdi
Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand.
Environ Res. 2006 Jul;101(3):294-303. doi: 10.1016/j.envres.2005.12.012.
High blood lead levels have recently been documented in schoolchildren living in communities adjacent to boat-repair yards in southern Thailand. In this study, the spatial pattern of lead contamination of soil and household dust in an area surrounding several boat-repair yards is described, and household factors associated with elevated dust lead are identified. A cross-sectional spatial study was conducted in a coastal residential area within a distance of 2 km from three major boat-repair yards situated on the east coast of peninsular Thailand. Household dust specimens were collected from an undisturbed position in the residences of children, aged 4-14 years, sampled randomly from all children living in the study area. Soil specimens were obtained from the interstices of a square grid, 70 x 70 m2, superimposed on the area. Geographic coordinates of residence and soil sampling positions were recorded and semivariograms and kriging used to contour the spatial distribution of lead in dust and soil. Environmental lead levels were also modeled in terms of direction and minimum distance from a boat-repair yard and, for household dust lead content, in terms of household variables, including occupation of household members in boat-repair work, type of house construction, and general cleanliness. Household dust and soil lead content ranged from 10 to 3025 mg/kg and from 1 to 7700 mg/kg, respectively. The distribution of soil lead peaked at the location of the boat-repair yards, but outside the yards the distribution was generally below 400 mg/kg and irregular. About 24% of household dust lead specimens were equal to or above 400 mg/kg, but showed significant decrease with increasing distance from the boat-repair yards, at rates of between 7% and 14% per 100 m. In houses where a family member was a worker in one of the major boatyards and in houses where occasional repair of small boats was undertaken, household dust lead levels were significantly elevated, by 65% (95% CI: 18-130%) and 31% (95% CI: 5-63%), respectively. Siting of boat-repair yards at a distance from residential areas and measures to reduce the spread of lead-containing dust are recommended to alleviate the problem of elevated household dust lead levels.
最近有记录表明，泰国南部与修船厂相邻社区的学童血铅水平很高。在本研究中，描述了几个修船厂周边地区土壤和家庭灰尘中铅污染的空间格局，并确定了与灰尘铅含量升高相关的家庭因素。在泰国半岛东海岸距离三个主要修船厂2公里范围内的沿海居民区开展了一项横断面空间研究。从研究区域内所有4至14岁儿童居住地未受干扰的位置采集家庭灰尘样本。土壤样本取自叠加在该区域上的70×70平方米方形网格的空隙处。记录居住地和土壤采样位置的地理坐标，并使用半变异函数和克里金法绘制灰尘和土壤中铅的空间分布等值线图。还根据与修船厂的方向和最短距离对环境铅水平进行建模，对于家庭灰尘铅含量，则根据家庭变量进行建模，包括家庭成员从事修船工作的职业、房屋建筑类型和总体清洁程度。家庭灰尘和土壤中的铅含量分别为10至3025毫克/千克和1至7700毫克/千克。土壤铅的分布在修船厂所在地达到峰值，但在船厂外，分布一般低于400毫克/千克且不规则。约24%的家庭灰尘铅样本等于或高于400毫克/千克，但随着与修船厂距离的增加，铅含量显著下降，每100米下降率在7%至14%之间。在家庭成员为主要船厂工人之一的家庭以及偶尔进行小船修理的家庭中，家庭灰尘铅水平显著升高，分别升高了65%（95%置信区间：18-130%）和31%（95%置信区间：5-63%）。建议将修船厂选址在远离居民区的地方，并采取措施减少含铅灰尘的扩散，以缓解家庭灰尘铅水平升高的问题。
