The association among metals and changes in their concentrations in the treatment of lead poisoning in lead-exposed workers

High-throughput metallomics studies on lead-exposed workers are rare, and the effects of lead exposure on other metals, as well as the loss of trace metals during such treatments, remain unclear.

We recruited 1091 lead-exposed and 75 lead-poisoned workers undergoing calcium disodium ethylenediaminetetraacetate (CaNa₂EDTA) treatment. Urine samples were analyzed for 33 metals/metalloids using inductively coupled plasma mass spectrometry (ICP-MS). In lead-poisoned workers, first morning urine was collected daily over a 15-day two-course of lead elimination treatment, plasma metals were also measured pre- and post-treatment.

In the high-lead group, urinary concentrations of 22 elements-including Fe, Zn, Mg, Ca, Cd, U, and Cu-were significantly higher than in the low-lead group. During the two CaNa₂EDTA treatment cycles, urinary concentrations of Zn, Fe, and Cd showed trends similar to those of Pb, whereas Rb showed an opposite trend; however, Cd exhibited a one-day lag effect relative to Pb. We estimated that during lead elimination therapy, additional losses of 5.11 μg/L·kg Fe, 11.71 μg/L·kg Pb, and 62.23 μg/L·kg Zn occurred per kilogram of body weight. Furthermore, plasma iron (Fe) and lead (Pb) levels decreased by 13.30% and 61.74%, respectively, following CaNa₂EDTA treatment.

Metal elements showed significant associations in lead-exposed workers, which may reflect either metabolic interactions or co-exposure in the occupational setting. Preliminary evidence suggests a potential link between CaNa₂EDTA treatment and increased excretion of iron (Fe) and zinc (Zn). Given this, clinicians may wish to be alert to the possibility of monitoring these elements.