Objectives Bone lead level is a good indicator of cumulative exposure. Aim research paper was to characterize lead exposure and identify main predictors of bone lead in workers at a lithography press.

Methods The study population consisted of 90 active workers. Their bone lead levels were determined using the X - K fluorescent rays method. Measurements were in micrograms lead per gram mineral bone (μgPb/gmb) in patella (PbP), tibia (PbT), blood (PbB), air (PbA), and lead present on hands before (PbBe) and after washing (PbAf). Two multiple linear regression models were constructed for each bone, because colinearity.

Results Mean, standard deviation (SD), and [range] were as follows. Age: 45 years (13) [20, 75]; seniority at the lithography press: 10.6 years, (9.3) [1, 40]; seniority at both printing presses: 20 years (15.5) [1, 65]; PbB: 12.3 mg/dL + 5.2, [3.4, 30.3]; PbP: 43.3 μgPb/gmb + 28.5 [-4.82, 136.9], PbT: 25.9 μgPb/g + 18.8 [-20.1, 74.2]; PbA 0.54 (mg/m³). GM (geometric mean): PbBe: 848.1 mg/m² [27, 158 537] and PbAf 73 mg/m² [3, 1463]. The PbP and PbT models explain 44% and 55% of accumulated lead variability, respectively; their predictors were: PbB β = 1.24 (p = 0.020) and β = 0.93 (p = 0.003); the seniority total years sum at both presses, β = 0.76 (p<0.001) and β = 0.34 (p = 0.007); the exposure categories: medium β = -1.60 (p = 0.83) and β = 2.79 (p = 0.52); high, β = 12.5 (p = 0.16) and β = 16.9 (p = 0.004); and very high, β = 15.4 (p = .048) and β = 18.0 (p<0.001), respectively, using low exposure as a reference.

Conclusions Although air lead exposure was low, bone lead concentrations were high, similar to those found in workers with greater exposure. In both models the PbP and PbT accumulation is determined by the intensity of exposure (PbB) and the seniority sum years with lead exposure, as well as various exposure levels, according to the workplace, and working an additional shift at a similar press.