Kawai M
Br J Ind Med. 1976 Aug;33(3):187-92. doi: 10.1136/oem.33.3.187.
Sixty-six workers engaged in lead-glazing pottery with a presumed moderate exposure to lead were studied. The group comprised 20 men with long-term exposure to lead and positive laboratory signs of increased lead absorption (Group A); 22 with long-term exposure and negative laboratory signs (Group B); 11 with short-term exposure and positive laboratory signs (Group C); and 13 with short-term exposure and negative laboratory signs (Group D). In addition, 14 workers employed in casting the kelmet alloys with presumed heavy exposure to lead (Group E) and seven healthy individuals (Group F) were included. Urine samples from all the subjects were analysed to determine, first, the total lead using the ashing technique, and then the precipitable lead using the coprecipitation technique of Cholak, Hubbard, and Burkey (1948), but modified slightly by us. Thus, the non-precipitable lead fraction in urine was the difference between the two measurements and this was also expressed as a percentage of the total lead. The mean total lead and the mean proportion of non-precipitable lead were 0.62 mumol/l and 48.7%, 0.35 mumol/l and 44.9%, 0.40 mumol/l and 48.9%, 0.17 mumol/l and 24.6%, 1.43 mumol/l and 44.3%, 0.14 mumol/l and 18.8% for Groups A, B, C, D, E, and F respectively, showing that a large part of urinary lead was eliminated as precipitable lead in Groups D and F who had normal lead excretion, while about half was eliminated as non-precipitable lead in the other four groups who had excessive lead excretion. No essential difference in the proportion of non-precipitable lead among Groups A, B and C excluded the possibility that the proportion might be directly related to the period of exposure to lead and to the laboratory findings of excessive lead absorption. The mean proportion of non-precipitable lead for the physiological (up to 0.240 mumol/l), intermediate (0.241 to 0.721 mumol/l), and excessive (above 0.722 mumol/l) total lead levels was 26.7, 41.3, and 52.3% respectively, in the lead workers comprising Groups A, B, C, and E each showing increased lead excretion when grouped together. these data suggested that, when urinary lead is within the normal range, it is excreted largely as precipitable lead even in individuals exposed to lead, and that the principal conditions determining the excretion of non-precipitable lead would be the current or recent degree of lead absorption. The excretory mechanisms and the biological significance of the non-precipitable lead are also discussed.
对66名从事铅釉陶器制作、推测铅暴露程度为中度的工人进行了研究。该组包括20名长期接触铅且实验室检查显示铅吸收增加呈阳性的男性（A组）；22名长期接触铅但实验室检查呈阴性的工人（B组）；11名短期接触铅且实验室检查呈阳性的工人（C组）；以及13名短期接触铅且实验室检查呈阴性的工人（D组）。此外，纳入了14名从事凯尔米特合金铸造、推测铅暴露程度较高的工人（E组）和7名健康个体（F组）。分析了所有受试者的尿液样本，首先采用灰化技术测定总铅含量，然后采用Cholak、Hubbard和Burkey（1948年）的共沉淀技术，但我们对其进行了轻微修改来测定可沉淀铅含量。因此，尿液中不可沉淀铅部分是两次测量值之间的差值，并且这也表示为总铅的百分比。A、B、C、D、E和F组的平均总铅含量及不可沉淀铅的平均比例分别为0.62μmol/L和48.7%、0.35μmol/L和44.9%、0.40μmol/L和48.9%、0.17μmol/L和24.6%、1.43μmol/L和44.3%、0.14μmol/L和18.8%，这表明在铅排泄正常的D组和F组中，大部分尿铅以可沉淀铅的形式排出，而在其他四组铅排泄过量的组中，约一半以不可沉淀铅的形式排出。A、B和C组不可沉淀铅比例没有本质差异，排除了该比例可能与铅接触时间和铅吸收过量的实验室检查结果直接相关的可能性。在A、B、C和E组的铅作业工人中，生理水平（高达0.240μmol/L）、中间水平（0.241至0.721μmol/L）和过量水平（高于0.722μmol/L）的总铅含量下，不可沉淀铅的平均比例分别为26.7%、41.3%和52.3%，这几组工人合在一起时均显示铅排泄增加。这些数据表明，当尿铅在正常范围内时，即使是接触铅的个体，其尿铅也主要以可沉淀铅的形式排出，并且决定不可沉淀铅排泄的主要因素将是当前或近期的铅吸收程度。还讨论了不可沉淀铅的排泄机制及其生物学意义。
