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February 15, 1980

Contaminants in Clinical Reverse Osmosis Water Purification Systems

JAMA. 1980;243(7):649. doi:10.1001/jama.1980.03300330013010

To the Editor.—  Reverse osmosis (RO) membrane separation processes have been successfully used by industry for several years to generate high purity water for injectables. More recently, miniature RO plants have been designed to produce injectables and dialysate solutions for hemodialysis and peritoneal dialysis in health care facilities. Existing commercial systems based on asymmetric cellulose acetate membranes have good separation properties for a number of solutes.1 However, their behavior is such that certain compounds are not excluded; in fact, a few are transported preferentially and concentrated by the membrane.2,3 This is in contrast with widely held views in engineering circles that regard RO membranes as sieves that filter largeand medium-sized molecules without regard to their chemistry.Poorly separated compounds include many common municipal water impurities such as pesticides, natural products, and industrial contaminants, which are found in high concentrations in some localities at certain times of the year.