[A study of the literature on the concentrations of XXXX , lead, @entity3409 and @entity349 in body fluids and tissues to define normal values and detection of overload. 1. Description of analytical methods and @entity3494 ].

@entity1 @entity137 @entity349 @entity3409 @entity3494 @entity734
The present review covers 208 papers dealing with determination of the metals @entity3494 , @entity3409 , lead and @entity349 in @entity1 biologic material. A comprehensive data bank survey of the literature from January 1980 to April 1984 was conducted and supplemented by review of some earlier publications. As shown by comparison of the results from a number of papers, the various state-of-the-art methods for determining metal content in biologic materials (e.g., atomic absorption spectrophotometry, neutron activation analysis, and x-ray fluorescent analysis) appear to be equally sensitive and reliable. These detection methods are suited to determination of the above metals in the following media: @entity3494 in urine, hair; @entity3409 in blood, urine, hair, renal cortex; lead in blood, hair; @entity349 in blood, urine, hair. To permit better comparison of the results presented in various publications, agreement must be reached on use of uniform concentration units and participation in quality control programs. Safe levels of chronic biological exposure overlap with concentrations which cause health effects or measurable impairment of body function over a wide range. Individual sensitivity to biological exposure varies. In a number of studies, metal concentrations are measured in symptom-free @entity1 which cause symptoms in @entity1 examined in other studies. Due to differences in the sensitivity of detection of symptoms, the range of minimum levels of biological exposure considered to be associated with deleterious health effects (levels of critical exposure) is unacceptably broad. Minimum levels of critical exposure should protect against development of early symptoms of @entity137 . If the lowest published critical levels of biological exposure are taken as a cutoff, then a sizable portion of the @entity1 currently revealing metal exposure in any of the reported media exceeds such levels. Symptoms of detrimental effects should be detectable in such @entity1 and should be investigated. In establishing and evaluating current minimum levels of critical chronic metal exposure, there is a general need for a quantitative increase in determinations and for a qualitative increase in the sensitivity of detection of symptoms and other health effects--in order to avoid @entity734 on reports of acute @entity137 . When detected levels of a given metal are in a range held to be normal, exclusion of toxic effects and poisoning requires additional consideration of clinical findings.
