1. Unité de toxicologie industrielle et de médecine du travail, Faculté de médecine, Université catholique de Louvain, Clos Chapelle‐aux‐Champs 30, bte 30.54 B‐120 Bruxelles Belgique <bernardtoxi.ucl.ac.be> 2. Laboratoire universitaire de médecine du travail, Faculté de médecine, 1, place de Verdun, 59045 Lille cedex France 3. CERESTE, Laboratoire de toxicologie, Faculté de pharmacie, Avenue Oscar Lambert 1, 59037 Lille cedex France
Few studies have examined the long‐term effects of low‐grade environmental exposure to heavy metals on children‘s kidneys and nervous systems. The present survey focused on children living near two foundries in Northern France (Auby and Noyelles‐Godault, Nord Pas‐de‐Calais; n ∓ 200: 99 girls, 101 boys), in an area with high levels of heavy metal contamination in the soil (lead: 100‐1, 700 ppm, cadmium: 0.7‐233 ppm, zinc: 101‐22,257 ppm). It measured lead, cadmium, and mercury levels in their blood and urine, along with several renal biomarkers (albumin, beta 2‐microglobulin, retinol‐binding protein, brush border antigens, N‐acetyl‐beta‐D‐glucosaminidase (NAG), transferrin, and Clara cell secretory protein) and serum prolactin and urinary homovanillic acid, both peripheral dopaminergic markers recently implicated in the neurological effects of lead and mercury. The results were compared with those from children of similar age living in uncontaminated areas of the same district (200 controls: 101 girls, 99 boys). The impact of heavy metal exposure was studied by multiple regression analysis. Although lead and cadmium blood levels (Pb‐B, Cd‐B) were higher in boys and in the contaminated area, the relatively low geometric mean concentrations of heavy metals indicate low absorption from the environment (Pb‐B: 39.5 µg\L, range 4.6‐165 µg\L, Cd‐B: 0.51 µg\L, range 0.15‐1.91 µg\L, Hg‐U: 1.05 µg\g creatinine, range 0.03‐18.7 µg\g creatinine, n ∓ 200). No correlation was observed between heavy metal levels and either renal or dopaminergic markers. Weak positive correlations were nonetheless found between NAG and Cd‐B (n ∓ 230, r
2 ∓ 0.06, p ∓ 0.0002) after adjustment for creatinine and body mass index, and between HVA‐U and Pb‐B (n ∓ 121, r
2 ∓ 0.04, p ∓ 0.03) in the population of 121 children with Pb‐B greater than 50 µg\L. These weak associations, in the absence of any other positive correlations, indicate that chronic environmental exposure to heavy metals, sometimes present in high concentrations in soil around old foundries, leads to only moderate absorption in the bodies of children living in the contaminated area: renal and dopaminergic effects are minimal.