Hair-Pb longitudinal profiles and blood-Pb in the population of young Slovenian males

Abstract

Hair-Pb longitudinal profiles of 25 mm hair length were measured in a population of Slovenian men (aged 18–25 years) using “tape sandwich” solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS). From these data two parameters related to Pb exposure were deduced. Hair-Pb proximal (H-Pbprox.) denotes the Pb content of the proximal 3 mm hair segment, while Hair-Pb average (H-Pbaver.) denotes the average Pb content of a 25 mm hair length. The former were found to be on average at least a factor of 2 lower than the H-Pbaver. values that are normally reported in the literature for hairs of 20–50 mm length. Hair-Pb gradient (H-Pbgrad.) defined as the difference in Pb content between the distal (25 mm) and the proximal (3 mm) hair segments divided by the hair length was found to be highly correlated to the level of air Pb pollution ( R = 0.9931 ; P<0.001; n = 5 ), while association between H-Pbprox. and air-Pb was not significant ( R = 0.5765 ; P>0.05; n = 5 ). Simultaneously, lead in whole blood (B-Pb) was determined by ETAAS as another parameter of Pb exposure. The frequency distribution of log B-Pb values followed a symmetrical Gaussian shape with a median value of 35 μg Pb/L. Log H-Pbprox. frequency distribution, on the contrary, showed a Poissonian shape. Transformation of the data revealed the existence of four homogeneous groups of males with different median H-Pbprox. values (40, 86, 326 and 2500 ng/g). The major proportion of the Slovenian male population (∼70%) has H-Pbprox. contents between 60 and 600 ng/g. A weak but statistically significant association was found between logs H-Pbprox. and B-Pb ( R = 0.3957 ; P<0.05; n = 247 ) but when only those subjects were retained whose both parameters were determined with reasonable accuracy and were either above or below the predetermined value (B-Pb=50 μg/L; H-Pbprox.=450 ng/g), substantial improvement in the strength of correlation was observed ( R = 0.7049 ; P<0.01; n = 84 ). The poor strength of association between these parameters was attributed to the large variation in Pb intake and different kinetics of Pb appearance in hair and blood. This statement is consistent with reports dealing with the relationship between H-Pb and B-Pb found in the literature.