Evolution of erythrocyte and urine lead concentrations after cutaneous exposure to mud packs embedded into micro-perforated polyethylene bags according to the protocol used in French medical spas

Abstract

Lead (Pb) is an environmental pollutant which may cause harmful effects on human health. It may be present within the mud-packs deposed on patient'skin for treating some rheumatologic conditions. We aimed to evaluate the diffusion of Pb from therapeutic mud-packs toward the human body in order to exclude safety concerns.We quantified Pb using inductively-coupled plasma mass spectrometry in blood (erythrocytes) and urine (raw concentration and divided by creatinine concentration) of 35 young healthy volunteers before and after the 21-day pelotherapy procedure from French medical spas (i.e hot micro-perforated polyethylene bags embedded-mud packs soaked in mineral water and deposed during 10 min on five cutaneous sites, in 5-day sequences during 3 consecutive weeks). We did not evidence a significant increase in their erythrocyte (p: 0.89) or urine (p: 0.96) concentrations when comparing pre- and post-treatment samples by the bilateral apparied Student test. These levels were markedly inferior to the recommended cut-off in all our participants taking into account the exclusion of individuals with extreme urinary creatinine values. From our sample including individuals with an optimal transcutaneous diffusion capacity (young persons with low subcutaneous fat mass) we conclude that there is no risk of Pb overexposure in patients receiving this type of pelotherapy regimen.