Jones K, Cocker J, Dodd L J, Fraser I
Health & Safety Laboratory, Broad Lane, Sheffield S3 7HQ, UK.
Ann Occup Hyg. 2003 Mar;47(2):145-50. doi: 10.1093/annhyg/meg016.
We have previously reported that solvent vapours can be absorbed through the skin and that the extent varies markedly and depends on the chemical. For some chemicals, the extent of absorption is significant, e.g. for 1-methoxy-2-propanol dermal absorption accounts for up to 14% of the total absorbed dose after 8 h exposure at the OES. We have conducted a second study using 2-butoxyethanol to investigate the influence of temperature, humidity and clothing on the dermal absorption of vapours. As for the first study, the extent of dermal absorption was determined by biological monitoring to measure the resultant body burden of the chemical.
Four volunteers were exposed on nine occasions. For eight of these exposures they wore air-fed half-masks to supply clean air for the inhalation route. The 'baseline' conditions (one 'whole body' and one 'skin only' exposure) were 25 degrees C, 40% relative humidity with volunteers wearing shorts and T-shirt. For each subsequent exposure, a single parameter was changed: humidity (60%, 65%), temperature (20 degrees C, 30 degrees C) or clothing (minimal and overalls). Finally, a 'industrial scenario' was conducted where volunteers wore overalls over their shorts and T-shirts and environmental conditions reflected high temperature and high humidity (30 degrees C, 60%), such as might be encountered in a tank-cleaning operation or similar.
Results show that 'baseline' dermal absorption of 2-butoxyethanol vapour was, on average, 11% of the total absorbed dose. Higher temperature (30 degrees C, mean 14%, P = 0.03) and greater humidity (65% RH, mean 13%, P = 0.1) increased dermal absorption. The wearing of whole-body overalls did not attenuate absorption (mean 10%). By combining several factors together in the 'industrial scenario', dermal absorption of vapours was significantly increased with a mean of 39% of the total absorbed dose.
The work has shown that dermal absorption of vapours can be significant and that environmental conditions may affect the absorption. Some types of protective clothing may not be suitable to reduce absorption. The possibility of dermal absorption of vapours should be considered particularly for workers in high vapour concentration conditions where control of exposure relies on respiratory protection.
我们之前曾报道过，溶剂蒸汽可经皮肤吸收，且吸收程度差异显著，取决于化学物质本身。对于某些化学物质，吸收程度颇为可观，例如在职业接触限值（OES）下暴露8小时后，1 - 甲氧基 - 2 - 丙醇的皮肤吸收量占总吸收剂量的14%。我们开展了第二项研究，使用2 - 丁氧基乙醇来探究温度、湿度和衣物对蒸汽皮肤吸收的影响。与第一项研究相同，皮肤吸收程度通过生物监测来确定，以测量化学物质在体内的最终负荷量。
四名志愿者接受了九次暴露实验。其中八次暴露时，他们佩戴供气式半面罩，通过吸入途径提供清洁空气。“基线”条件（一次“全身”暴露和一次“仅皮肤”暴露）为25摄氏度、相对湿度40%，志愿者穿着短裤和T恤。在随后的每次暴露中，改变一个单一参数：湿度（60%、65%）、温度（20摄氏度、30摄氏度）或衣物（最少衣物和工作服）。最后，进行了一次“工业场景”实验，志愿者在短裤和T恤外面穿上工作服，环境条件模拟高温高湿（30摄氏度、60%），比如在罐体清洗作业或类似场景中可能遇到的情况。
结果显示，2 - 丁氧基乙醇蒸汽的“基线”皮肤吸收量平均占总吸收剂量的11%。较高温度（30摄氏度，平均14%，P = 0.03）和较大湿度（相对湿度65%，平均13%，P = 0.1）会增加皮肤吸收。穿着全身工作服并不会减弱吸收（平均10%）。在“工业场景”中综合多种因素后，蒸汽的皮肤吸收量显著增加，平均占总吸收剂量的39%。
该研究表明，蒸汽的皮肤吸收量可能颇为可观，且环境条件可能会影响吸收。某些类型的防护服可能并不适合减少吸收。对于处于高蒸汽浓度环境中的工人，尤其是在依靠呼吸防护来控制暴露的情况下，应特别考虑蒸汽经皮肤吸收的可能性。
