[Evaluation of the dose of mercury in exposed and control subjects]. / Valutazione delle dosi di mercurio negli esposti e nei controlli.

OBJECTIVES: The aim of this paper was to analyse the concentrations of HgU and HgB in three different groups: 122 workers exposed, 18 workers formerly exposed and 196 subjects not occupationally or environmentally exposed to mercury. METHODS: All the subjects filled out a questionnaire concerning personal data, lifestyle, occupational or non-occupational exposure to Hg and medical history. The amalgam fillings area was measured by a standardised method. RESULTS: Urinary mercury excretion was significantly greater in the group of the exposed workers respect to the group of subjects not occupationally exposed (Median value of 8.3 micrograms/g creatinine and the 5 degrees and 95 degrees percentile respectively of 2.66 e 23.50 micrograms/g creatinine against Median value of 1.2 micrograms/g creatinine and the 5 degrees and 95 degrees percentile respectively of 0.18 and 5.42 micrograms/g creatinine). U-Hg in formerly exposed workers were comparable to U-Hg in non-occupationally exposed subjects, with a median value of 1.6 micrograms/g creatinine. B-Hg values were similar in the three groups: the median value was 3.1 micrograms/l in the non-occupationally exposed, 4.0 micrograms/l in the exposed workers and 3.9 micrograms/l in the past exposed. These value were not significantly different. Among the considered variables (amalgam fillings, fish consumption, age, sex, alcohol intake, chewing-gum and smoking) dental amalgam and fish consumption were significantly related with the Hg urinary excretion and the B-Hg levels. This is particularly true considering the subjects altogether: for the exposed workers, indeed, the occupational exposure was the most relevant variable. CONCLUSIONS: The results of the present research confirmed that the U-Hg excretion in non-occupationally exposed subjects is influenced by amalgam dental fillings. Furthermore, in our study Hg urinary excretion was significantly related with fish consumption. This fact can be explained, according to several recent experimental human and animal trials, considering that methylmercury contained in fish is partially converted, through breakage of the carbon-Hg bond, into Hg inorganic forms, which accumulate in the kidney and have a urinary excretion pathway.

[Urinary and blood markers of internal mercury dose in workers from a chlorakali plant and in subjects not occupationally exposed: relation to dental amalgam and fish consumption]. / Indicatori urinari ed ematici di dose interna di mercurio in lavoratori di un impianto clorosoda e in soggetti non professionalmente esposti: relazione con gli amalgami dentali ed il consumo di pesce di mare.

OBJECTIVES: The aim of this paper was both to evaluate the internal dose of Hg in occupationally exposed workers (35 Chloralkali workers) compared to that of non occupationally exposed controls (40 workers of the same plant of Portotorres and 22 residents on the island of Carloforte, usual consumers of local fish, mostly tuna fish with relatively high Hg levels) and to assess the relevance of environmental and individual exposure factors linked to lifestyle, sea fish consumption and amalgam fillings. METHODS: All subjects filled out a questionnaire concerning the working history and lifestyle. The amalgam fillings area was measured by medical inspection using a standardised schedule attached to the questionnaire. Mercury in urine (HgU) was measured in all cases, while in a subgroup of our study total blood mercury (HgB) and its organic and inorganic component were also assessed. Furthermore, for 8 of the Carloforte group mercury in hair was also available. RESULTS: Values of urinary mercury excretion of the Chloralkali workers were significantly higher (median value of 15.4, range 4.8-35.0 micrograms/g creatinine, 94.3% of the cases having values > 5 micrograms/g creatinine) than those observed both among the reference group (median value of 1.9, range 0.4-5.6 micrograms/g creatinine, 12.5% of the cases having values a little greater than 5 micrograms/g creatinine) and among the residents in Carloforte (median value of 6.5, range 1.8-21.5 micrograms/g creatinine, 59.1% of the cases having values > 5 mcg/g creatinine). The HgU values observed in this group were in turn significantly higher than those of the non occupationally exposed workers living near Sassari (p = 0.03). Only in this last group were the HgU concentrations statistically significantly related to the extension of the amalgam fillings area (Pearson r = 0.53, p < 0.01). In the Carloforte group HgU was significantly related to the number of fish meal consumed per week (Pearson r = 0.48, p < 0.02). HgB (median value of 5.9, range 3.4-21.6 micrograms/l) as well as its inorganic component (median value of 2.4, range 1.8-4.6 micrograms/l) were significantly higher in the Chloralkali group compared to the other two groups. In all cases of the Carloforte group the ratio between the organic component and the total HgB was higher than 85%, while this ratio was significantly lower in the other two groups. The relationship between HgU and HgB was statistically significant, considering both total blood mercury and the inorganic and the organic components separately. A statistically significant relationship between the sea fish consumption per week and both total HgB (Pearson r = 0.82) and the organic component in this matrix (Pearson r = 0.84, p < 0.001) was observed among 16 non-occupationally exposed subjects. However, the significant relationship between organic blood mercury and sea fish consumption was almost entirely supported by the data observed in the Carloforte group. Total hair mercury levels analysed in 8 subjects of the Carloforte group were high (median value of 9.6, range 1.4-34.5 micrograms/g) and significantly related to sea fish consumption, and to both the individual Hg urinary excretion (Pearson r = 0.83) and to the organic component of blood mercury (Pearson r = 0.87). CONCLUSIONS: According to several experimental human and animal trials and to some recent studies on methylmercury toxicokinetic models, our results suggest that the organic compounds absorbed by usual sea fish consumption may be partially demethylated, increasing the inorganic Hg concentration in the kidney and consequently its urinary excretion, as was observed in the Carloforte group.

Results of dental amalgam removal and mercury detoxification using DMPS and neural therapy.

Sixty consecutive patients who had undergone replacement of dental amalgam fillings and a protocol of nutritional support and heavy metal detoxification using dimercapto-propanyl-sulfate and neural therapy were surveyed. A questionnaire was mailed to the patients and 42 responded, resulting in a response rate of 70%. The reasons for undergoing treatment were many, ranging from a patient's desire to avoid potential health problems in the future to treatment of serious current disease. Although medical diagnoses were made when possible before treatment, this survey studied only the patients' estimations of their most distressing symptoms and their evaluations of response to treatment. The most common complaints were problems with memory and/or concentration; muscle and/or joint pain; anxiety and insomnia; stomach, bowel, and bladder complaints; depression; food or chemical sensitivities; numbness or tingling; and eye symptoms, in descending order of frequency. The most distressing symptoms were headache and backache, fatigue, and memory and concentration problems. Headache and backache responded best to treatment, but all symptoms showed considerable improvement on average. Of the respondents, 78% reported that they were either satisfied or very satisfied with the results of treatment, and 9.5% reported that they were disappointed.

Dental amalgam mercury exposure in rats.

The aim of this study was to measure the distribution of mercury, in tissues of rats exposed to amalgam over a two months period. Possible interaction of mercury with copper and zinc in organs was also evaluated. Rats were either exposed to mercury from 4 dental amalgams, or fed the diet containing powdered amalgam during two months. Mercury was measured in the kidney, liver and brain, copper in kidney and brain and zinc in kidney. The results showed significantly higher concentrations of mercury in the kidneys and the brains of rats in both exposed groups compared to control. Even after two months of exposure to mercury brain mercury concentration in rats with amalgam fillings was 8 times higher than in the control and 2 times higher than in rats exposed to amalgam supplemented diet. The highest mercury concentration in the latter group was found in the kidneys and it was 5 times higher than in the control group. We found no significant differences between mercury levels in exposed and control rat's liver. Exposure to mercury from dental amalgams did not alter the concentrations of copper and zinc in the tissues. Histopathological analyses of rats tissues did not show any pathological changes. These results support previously proposed nose-brain transport of mercury released from dental amalgam fillings.

Mercury in human colostrum and early breast milk. Its dependence on dental amalgam and other factors.

The mercury concentration in 70 breast milk samples (Hg-M) from 46 mothers, collected within the first 7 days after delivery, was determined by cold vapour atomic absorption spectrometry. For comparison, 9 formula milk samples (reconstituted with Hg-free water) were investigated. The Hg-M in the human milk samples ranged from < 0.2 to 6.86 micrograms/L (median 0.37), in the formula milk samples from 0.4 to 2.5 micrograms/L (median 0.76). The Hg-M in the breast milk samples correlates positively with the number of maternal teeth with dental amalgam. The mean Hg-M of amalgam-free mothers was < 0.2 microgram/L, while milk from mothers with 1-4 amalgam fillings contained 0.57 microgram/L, with 5-7 fillings 0.50 microgram/L and with more than 7 fillings 2.11 micrograms/L. Hg-M correlated negatively to the day after delivery. Frequency of fish consumption tends to influence Hg-M positively, while the age of the mother shows no significant correlation. In the first 2 to 3 days after delivery some colostrum samples with Hg-M higher than in formula milk were found. Later on, the Hg-concentration in the breast milk was equal or even lower to that in formula milk. The higher Hg burden of infants' tissues from mothers with dental amalgam, as reported previously, must be explained (1) by a prenatal transfer of Hg from the mother's fillings through the placenta to the fetus, followed by a redistribution of this Hg in the body of the newborn, and (2) an additional burden via breast milk. Nevertheless, the comparison of Hg-M in breast and formula milk, the relatively moderate Hg burden in both kinds of milk, and the multiple manifest advantages of breast feeding speak against any limitation of nursing, even for mothers with a large number of dental amalgam fillings.