Comment on “Effect of Mercury Exposure on Renal Function and Hematological Parameters among Artisanal and Smallscale Gold Miners at Sekotong, West Lombok, Indonesia”

Correspondence is not peer reviewed. Opinions expressed are that of the author.

With great interest, we have read the article by Ekawanti and Krisnayanti1 entitled “Effect of Mercury Exposure on Renal Function and Hematological Parameters among Artisanal and Smallscale Gold Miners at Sekotong, West Lombok, Indonesia” that is published in the Journal of Health & Pollution Vol. 5, No. 9, 2015. Ekawanti and Krisnayanti investigated the effects of mercury exposure on renal function along with the hematological parameters of gold miners and the community as a first indication of mercury exposure symptoms. The authors assessed the correlations between mercury exposure and several health parameters such as urine protein level, hemoglobin, hematocrit, urine and hair mercury levels in two different mercury exposure groups, miners and non-miners. This investigation concluded that miners and non-miners showed significant differences in all health parameters except for hair mercury value, which showed no significant difference between the miners and non-miners. The general population is primarily exposed to methylmercury through their diet (particularly seafood) and mercury from dental amalgam.2 Mercury is widely believed to be a main global contaminant of aquatic food chains.3 Numerous studies show that ingestion of fish contaminated with methyl mercury may cause adverse health effects, particularly when this exposure occurs in utero.4 It is worth noting that besides consumption of sea foods, mercury released from dental amalgam fillings should also be taken into account in these studies. Furthermore, we have also shown that exposure to electromagnetic fields generated in magnetic resonance imaging or electromagnetic fields generated by common mobile phones significantly increase the mercury release from dental amalgam restorations.5,6 These findings have been further confirmed by some microleakage studies.7,8 Moreover, Kursun et al. demonstrated that exposure to X-rays, an ionizing component of the electromagnetic radiation spectrum, can increase the mercury release from amalgam fillings.9 These findings have recently been reviewed by Mortazavi and Mortazavi.10 Therefore, as Ekawanti and Krisnayanti did not evaluate the income level of the study participants and their nutritional status, confounding factors such as the frequency of fish/seafood consumption and other parameters which affect the amount of mercury release from amalgam restorations, including the number of amalgam fillings, the size of the fillings, and the composition of amalgam have possibly decreased the accuracy of their findings. Moreover, any other factors that cause load over the restorations such as the pattern of tooth brushing, chewing habits, and bruxism in both miners and non-miners may have possibly affected the findings of this study.