Rogers C E, Tomita A V, Trowbridge P R, Gone J K, Chen J, Zeeb P, Hemond H F, Thilly W G, Olmez I, Durant J L
Center for Environmental Health Sciences, Massachusetts Institute of Technology,Cambridge, MA 02139, USA.
Environ Health Perspect. 1997 Oct;105(10):1090-7. doi: 10.1289/ehp.971051090.
We hypothesized that residents of Woburn, Massachusetts, had been exposed to as much as 70 microg/l of arsenic (As) and 240 microg/l of chromium (Cr) in drinking water from municipal supply wells G and H. To test this hypothesis, we measured the concentrations of As and Cr in 82 hair samples donated by 56 Woburn residents. Thirty-six samples were cut between 1964 and 1979, the period during which wells G and H were in operation. The remainder were cut either before 1964 (1938-1963; n = 26) or after 1979 (1982-1994; n = 20). Washed hair samples were analyzed by instrumental neutron activation. Exposure to the well water--measured as access--was estimated using well pumping records and a model of the Woburn water distribution system. Our results show that access to wells G and H water was not significantly correlated (95% confidence interval) with As and Cr concentrations measured in the hair of Woburn residents, but As concentrations have declined significantly over the last half century. Linear regression of As concentrations (micrograms per gram) upon year of hair cut and access to wells G and H water yielded a standard coefficient for year of -0. 0074 +/- 0.0017 (standard error; p = 2.5 -multiple- 10(-5)) and -0.12 +/- 0.10 (p = 0.22) for access. The r2 value for the model was 0.19. The geometric mean concentrations (geometric standard deviation) of As and Cr in the hair of residents who had access (i.e., relative access estimate >0) to wells G and H water (n = 27) were 0.14 (2.6) and 2.29 (1.8) microg/g, respectively; the geometric mean concentrations of As and Cr in all of the hair samples from residents who did not have access (1938-1994; n = 55) were 0.13 (3.0) and 2.19 (2.0) microg/g, respectively.
我们推测，马萨诸塞州沃本市的居民曾接触到来自市政供水井G和H的饮用水中高达70微克/升的砷（As）和240微克/升的铬（Cr）。为验证这一推测，我们测量了56位沃本市居民捐赠的82份头发样本中As和Cr的浓度。36份样本是在1964年至1979年期间剪下的，这期间水井G和H在运行。其余样本要么是在1964年之前（1938 - 1963年；n = 26）剪下的，要么是在1979年之后（1982 - 1994年；n = 20）剪下的。清洗后的头发样本通过仪器中子活化分析法进行分析。通过水井抽水记录和沃本市供水系统模型估算了对井水的接触情况（以接触程度衡量）。我们的结果表明，接触水井G和H的水与沃本市居民头发中测量的As和Cr浓度之间无显著相关性（95%置信区间），但在过去半个世纪里As浓度显著下降。根据头发剪下年份以及接触水井G和H的水情况对As浓度（微克/克）进行线性回归分析，得到年份的标准系数为 -0.0074 ± 0.0017（标准误差；p = 2.5×10⁻⁵），接触程度的标准系数为 -0.12 ± 0.10（p = 0.22）。该模型的r²值为0.19。接触水井G和H的水（即相对接触程度估计>0）的居民（n = 27）头发中As和Cr的几何平均浓度（几何标准差）分别为0.14（2.6）和2.29（1.8）微克/克；未接触（1938 - 1994年；n = 55）的居民所有头发样本中As和Cr的几何平均浓度分别为0.13（3.0）和2.19（2.0）微克/克。
