Chúng ta thường nói để đo tiếp xúc, đo nồng độ trong một môi trường thích hợp bề mặt cơ thể. Đối với đường hô hấp và tiêu hóa, điều này là tương đối đơn giản. Nhưng da hấp thụ liên quan đến da, cơ quan lớn nhất và kéo dài nhất của cơ thể. Làm thế nào là một trong những xác định bề mặt cơ thể thích hợp trong nhiều tình huống? Ví dụ, tắm vòi sen một số phần của cơ thể nhận được thường xuyên "hit" từ những giọt nước nhỏ, các phần khác của cơ thể có thể được liên. | 12 Dermal Exposure to VOCs while Bathing Showering or Swimming Lance A. Wallace . Environmental Protection Agency ret. Sydney M. Gordon Battelle Memorial Institute CONTENTS Parameters Affecting Dermal Indirect Measures of Dermal Showers and Baths. .292 Direct Measures of Dermal Absorption Using Continuous Breath Questions for Review .296 References .296 SYNOPSIS We often say to measure exposure measure the concentration in a medium next to the appropriate body surface. For inhalation and ingestion this is relatively straightforward. But dermal absorption involves the skin the body s largest and most extended organ. How is one to determine the appropriate body surface in many situations For example in showering some portions of the body are receiving occasional hits from small droplets of water other portions of the body may be constantly exposed as the water rivulets cascade downward still other parts . the hair and skull may be completely dry and unexposed. This chapter deals with how various exposure assessors have dealt with the problem of measuring dermal absorption. Although some efforts have been ingenious we will see that the problem remains unsolved. We begin with the history of how first indoor air and then the shower or bath were identified as providing major sources of exposure both inhalation and dermal to volatile organic compounds VOCs but most particularly chloroform. After a brief detour to investigate how chloroform gets into our water we review several models of exposure through the skin through contact with contaminated water. The central barrier to exposure is the stratum corneum SC which can be viewed as providing a resistance to molecular diffusion through the skin. Different chemicals have different diffusion rates based on their molecular characteristics. A crucial parameter is .
