Blood metal(loid)s, haemoglobin and goitre in pregnant women from the mercury-exposed and non-exposed environment (Aidarken area vs Kara-Suu area; Kyrgyz Republic).

OBJECTIVES

Aidarken is a region with mercury production from cinnabar and, to a lesser extent, from mercury-antimony-fluorite and waste recycling. Recent smelting emissions of elemental Hg vapour are low; however, combined with past pollution legacies, anaemia and iodine deficiency, the health effects for vulnerable populations are still possible. The study aimed to evaluate metal(loid)s status in Aidarken pregnant women vs those from an Hg-noncontaminated region.

METHODS

90 pregnant women (3rd trimester) aged 19-39 years were recruited into the cross-sectional study: Aidarken (n = 55) and Hg-uncontaminated Kara-Suu (n = 35) region. The fasting blood samples were analysed for 22 metal(loid)s by ICP-MS and haemoglobin. The difference in metal(loid) levels between the groups (and within groups according to the presence of goitre) was estimated by multiple variable linear regression models.

RESULTS

Metal(loid) blood levels were within reference ranges. We estimated the statistical significance of between-group differences for several metal(loid)s. Essential S, P, Fe, Ca, Mg, Co and Se and non-essential Hg, U, As, Cs and Rb were higher in the exposed than in the control group. On the contrary, the essential Na and Cu, and nonessential Sr and Ba were lower in the exposed vs controls. Mean haemoglobin levels didn't differ between the groups, while the incidence of goitre was higher in the exposed group (34.6 % vs 11.4 %). In the exposed group, the presence of goitre was estimated as a possible predictor for higher levels of Hg, Rb, Mn, Fe and Se.

CONCLUSIONS

We found no critical Hg-related health concern for Aidarken pregnant women. The nutritional status of some essential metal(loid)s was even better in the exposed than in the control group. However, the results may indicate that long-term chronic exposure to moderate Hg levels could worsen thyroid health issues in a given environmental (iodine-deficient region) and lifestyle (suboptimal use of iodinated salt) conditions.