Handbook of Solvents - George Wypych - ChemTech - Ventech!

20.4 Industrial solvents and kidney disease 1355
20.4 INDUSTRIAL SOLVENTS AND KIDNEY DISEASE
Nachman Brautbar
University of Southern California, School of Medicine,
Department of Medicine, Los Angeles, CA, USA
20.4.1 INTRODUCTION
Industrial solvents are used extensively in the industry, as well as modern living. The principle
class of components are the chlorinated and non-chlorinated hydrocarbons. The various
types of commonly used hydrocarbons are presented in Figure 20.4.1.
Figure 20.4.1. General classification of hydrocarbons based on general structure.[Adapted, by permission, from
A.T. Roy, Nephron, 58, 385, 1991.]
Solvents are absorbed into the human body through several routes including 1) inhalation
through the lungs, 2) absorption through the skin, 3) ingestion (in rare cases). The main
route of absorption is commonly pulmonary, the lung, and this depends on several factors
including the frequency of breathing, diffusion of solvent vapors across the alveolar membrane,
partial pressure of solvent vapor in inspired air and blood, and solubility of the solvent
in blood as the result of to air partition coefficient, and blood flow through the lungs. 1,2,3
Once in the circulation, 25% of the cardiac output which is about 1200 cc of blood per minute
passes through the kidneys. Therefore it is no surprise that with this amount of blood
passing through the kidney and carrying solvents (from either industrial inhalation, skin absorption,
and on rare occasions ingestion) the effects of solvents on the kidney has become
a practical clinical one.
Since inhaled hydrocarbons are readily absorbed into the blood stream and become
lipophilic and readily pass across the lipid membranes. In addition to reaching the kidney,
the solvents reach the brain (as does the most ancient solvent, alcohol) and enter the blood
brain barrier in high concentration.
Skin absorption is the second most important route for solvent entry into the body and
at times is much more significant than inhalation. The reason is that absorption of organic
solvent vapors by inhalation at the threshold limit value is insignificant and is less than 2%
of the amount absorbed via inhalation under the same exposure conditions. 3 In contrast, solvents
may be absorbed through the skin in significant amounts even at below the threshold
limit value. 3 Factors that effect the skin absorption of solvents include the composition of