Contribution of dermal absorption in occupational exposure to organic compounds

在化学化合物的职业暴露中，皮肤吸收和吸入都有助于化合物的侵入。为了预防暴露，重要的是要澄清哪种途径的贡献更大。本研究在接触毒死蜱（CP）、对叔丁基苯酚（PTBP）和4，4 '-亚甲基双（2-氯苯胺）（MBOCA）的工作场所进行了调查，并对它们的皮肤吸收进行了定量评价。本实验还对CP和PTBP在动物体内的代谢和尿排泄进行了研究.测定尿CP和PTBP排泄率。CP和PTBP均经腹腔注射给大鼠。80%以上的药物在注射后48 h内经尿液排出.本研究共进行了三次调查。第一次调查是对喷洒CP的白蚁控制操作员进行的。尿代谢物水平与操作者呼吸区附近空气中CP浓度无关，但与操作者上身CP接触量相关。CP的吸入几乎完全通过佩戴呼吸器来防止。结果表明，该作业场所CP对人体的侵入主要是通过皮肤吸收。第二次调查是在工人处理PTBP的工作场所进行的。从环境浓度、呼吸量、工作时间和呼吸机收集的PTBP量估计，尿中排出的PTBP量大于吸入量。这定量地表明PTBP的皮肤吸收的存在。第三次调查是对6名处理MBoca的工人进行的。虽然工人呼吸区附近空气中MBOCA水平分为二级，但尿代谢物水平分为三级。这定性地表明存在MBOCA的皮肤吸收。

In an occupational exposure to chemical compounds, both dermal absorption and inhalation contribute to invasion of the compounds. For prevention of the exposure, It is important to clarify which route contributes more highly. In the present study, we surveyed in work place where chlorpyrifos (CP), p-tert-butylphenol (PTBP) or 4,4'-methylenebis(2-chloroaniline) (MBOCA) was handled, and their dermal absorption was assessed quantitatively. We also studied on metabolism and urinary excretion of CP and PTBP in animal experiments.1. Urinary excretion rate-of CP and PTBP were studied. Both CP and PTBP were interaperitoneally injected to rats. More than 80% of them administered were excreted into urine within 48 h after the injection.2. There were three surveys in the present study. The first survey was performed for termite control operators who sprayed CP. The urinary metabolite levels were not correlated to CP concentration of air near the operators' breathing zone, but correlated to contact amounts of CP to their upper bodies. Inhalation of CP was almost completely prevented by the wearing of respirators. These results indicate that most of invasion of CP to bodies was accounted by the dermal absorption in this work place. The second survey was carried out in a work place where workers handled PTBP. Amounts of the urinary excretion of PTBP were more than the inhalation amounts estimated from their environmental levels, respiration volume, working time and the amounts of PTBP collected in respirators. This indicates the existence of dermal absorption of PTBP quantitatively. The third survey was done to six workers handling MBOCA. Although MBOCA levels in air near the workers' breathing zone were classified into two degrees, the urinary metabolite levels were divided into three degree. This indicates the existence of dermal absorption of MBOCA qualitatively.