The ubiquitous use of dental amalgam for over 180 years has resulted in the exposure of millions of dental workers to mercury. Dental amalgam contains approximately 50% mercury. Dental workers, ...including dentists, dental assistants, and dental hygienists, have been shown to have increased levels of mercury and suffer more from health issues related to mercury exposure than the general public. Mercury is known to be absorbed via inhalation or through the skin. There are many routine dental procedures that require the removal of dental amalgam by using the dental high-speed drill, which we suspected generates an occupational mercury exposure that is not sufficiently recognized.
We showed that drilling dental amalgam generates particulate that volatilizes significant amounts of mercury vapor generally for more than an hour after removal. The levels of mercury vapor created by this procedure frequently exceed the safety thresholds of several jurisdictions and agencies.
A significant, underrecognized source of localized exposure to mercury vapor was identified in this study. The vapor was created by microgram levels of particulate generated from dental amalgam removal with a high-speed dental drill, even when all feasible engineering controls were used to reduce mercury exposure. This exposure may explain why dental workers incur health effects when safety thresholds are not breached. The dispersion patterns for the particulate are not known, so the use of effective skin barriers and inhalation protection are required during amalgam removal to protect the dental worker from this form of occupational mercury exposure. Standard methodologies for occupational mercury exposure assessment appear to be inadequate when assessing mercury exposure during amalgam removal.
The link between restless legs syndrome (RLS) and the number of amalgam fillings in older people was investigated. Restless legs syndrome decreases the quality of life and impairs normal functioning. ...Mercury (in amalgam) may be toxic to nerve cells and may account for the incidence of RLS.
The relationship between RLS and the presence of amalgam in the teeth of 104 people aged 60-97 years old was determined. By using 4 questions, together with the diagnostic criteria from the internationally used questionnaire produced by the International Restless Legs Syndrome Study Group (IRLSSG), authors assessed the extent of the symptoms and occurrence of RLS. Careful medical history and medical examination were used for ascertaining each subject's type of restorative materials (i.e., amalgam or other metal) and the number of such fillings.
Subjects who answered "yes" (indicating presence of RLS) to the 4 subsequent questions had a significantly higher number of amalgam dental fillings as compared to the subjects without RLS symptoms. Presence of other metal dental restorative materials and the number of amalgam dental fillings reported in the past had no significant influence on RLS symptomatology.
Authors conclude that while examining the correlates of the appearance of restless legs syndrome the use of amalgam in the dentition should be taken into account. Med Pr. 2019;70(1):9-16.
Amalgam that is used for dental fillings contains approximately 50% elemental mercury. During dental student training, amalgam is often removed by drilling without the use of water spray and suction, ...which are protective measures in preventing mercury aerosol. In this study we measured mercury vapor levels in ambient air during amalgam removal as is typically performed in dental training.
Mercury vapor levels in ambient air were measured in a dental school laboratory during removal of amalgam fillings from artificial teeth set into a dental jaw simulator. Mercury vapor was measured under three conditions (25 measurements each): with the simultaneous use of water spray and suction, with the use of suction only, and with the use of neither suction nor water spray. These three conditions are all used during dental student training. Results were compared to Alberta occupational exposure limits for mercury vapor in order to assess potential occupational risk to students. Analysis of variance testing was used to compare data obtained under the three conditions.
When water spray and suction were used, mercury vapor levels ranged from 4.0 to 19.0 μg/m3 (arithmetic mean = 8.0 μg/m3); when suction only was used, mercury vapor levels ranged from 14.0 to 999.0 (999.0 μg/m3 represents the high limit detection of the Jerome analyzer) (arithmetic mean = 141.0 μg/m3); when neither suction nor water was used, the vapor levels ranged from 34.0 to 796.0 μg/m3 (arithmetic mean = 214.0 μg/m3).
The Alberta Occupational Health and Safety threshold limit value for mercury vapor over an eight-hour time-weighted period is 25.0 μg/m3. The absolute ceiling for mercury vapor, not to be exceeded at any time, is 125.0 μg/m3. When both water spray and suction were used, mercury vapor levels were consistently below this threshold. When suction without water spray was used, mercury vapor levels exceeded the safety threshold 8% of the time. When neither water spray nor suction was used, 36% of the mercury vapor readings exceeded the absolute ceiling value. To maximize safety, dental schools should train students to remove amalgam only while using water spray and high volume suction. Alternatively, students should use appropriate occupational hygiene personal protective equipment during amalgam removals.
Among Amazonian communities, exposure to methylmercury is associated mainly with fish consumption that may affect fetal development in pregnant women. Therefore a temporal assessment was performed to ...assess the exposure of reproductive aged women to mercury who reside in the riparian communities of São Luís do Tapajós and Barreiras located in the Tapajós basin of the Brazilian Amazon from 1999 to 2012. The total mercury concentration in the 519 hair samples was assessed by cold vapor atomic absorption spectrometry. Data analysis showed that the average total mercury concentration decreased from 1.066 to 0.743 μg/g in those years. In 1999 the proportion of volunteers with mercury levels ≥10 μg/g was approximately 68 %. In general, exposure to mercury decreased among women of reproductive age, but the potential risks to reproduction and human health is still an issue as 22 % of the woman continued showing high mercury levels (≥10 μg/g) in 2012.
The aim of the present study was to evaluate mercury and selenium concentrations in hair samples of reproductive age women from riverside communities of the Tapajós River basin. We studied 19 ...pregnant and 21 non-pregnant women, 13 to 45 years old, living in the region for at least 2 years, and having a diet rich in fish. The analysis of Se and total Hg were performed in the Instituto de Pesquisas Energéticas e Nucleares (IPEN, São Paulo, Brazil) by using a Varian AA220-FS atomic absorption spectrometer with a flow injection system. There were no differences between the two groups — pregnant and non-pregnant — concerning age (23.80
±
6.92 and 26.60
±
9.60 years old, respectively) and residential time (20.21
±
8.30 and 22.20
±
10.90 years, respectively). The geometric means and ranges for total Hg concentration were similar (
p
>
0.05): 8.25 μg/g (1.51–19.43) in pregnant and 9.39 μg/g (5.25–21.00) in non-pregnant women, respectively. Total Hg concentrations were also similar in different gestational stages. However, there was a significant difference between the two groups (
p
<
0.05, Student
t test) in relation to Se concentration: 0.61 μg/g (0.40–2.33) in pregnant and 2.46 μg/g (0.92–5.74) in non-pregnant women, respectively. We concluded that Hg exposure levels in reproductive age women were only slightly higher than a provisional tolerable weekly intake of MeHg would provide, that Hg concentration in maternal hair samples was independent of gestational age, and that low Se concentration in pregnant women indicates high mineral consumption by fetal organism to satisfy their metabolic requirements raised during pregnancy, including as a protective mechanism for Hg cytotoxic effects.
The aim of the study was to evaluate left ventricular diastolic function in workers occupationally exposed to mercury vapour without clinical presentation of cardiac involvement. The studies included ...115 workers (92 men and 23 women) occupationally exposed to mercury vapour without clinical presentation of cardiac involvement (mean age: 47.83±8.29). Blood samples were taken to determine blood lipid profile, urine was collected to estimate mercury concentration (HgU) and echocardiographic examination was performed to evaluate diastolic function of the left ventricle. In the entire group of workers occupationally exposed to mercury vapour without clinical presentation of cardiac involvement, Spearman correlations analysis demonstrated the following significant linear relationships: between body mass index (BMI) and ratio of maximal early diastolic mitral flow velocity/early diastolic mitral annular velocity (E/E`) (r=0.32, p<0.05), between serum HDL concentration and E/E` (r=−0.22, p<0.05), between HgU and E/E` (r=0.35, p<0.05), between HgU and isovolumetric relaxation time (IVRT`) (r=0.41, p<0.05), between HgU and ratio of maximal early diastolic mitral flow velocity/maximal late diastolic mitral flow velocity (E/A) (r=−0.31, p<0.05) and between serum HDL concentration and E/A (r=0.43, p<0,05). In logistic regression analysis it as shown that independent factors of left ventricular diastolic dysfunction risk in the study group included a higher urine mercury concentration, a higher value of BMI and a lower serum HDL concentration (ORHgU=1.071, ORBMI=1.200, ORHDL=0.896, p<0.05). Summing up, occupational exposure to mercury vapour may be linked to impaired left ventricular diastolic function in workers without clinical presentation of cardiac involvement.
► Study aimed at evaluation of LVDD in workers occupationally exposed to Hg. ► There was significant linear relationships between HgU and E/E`. ► Independent risk factor of LVDD in study group included higher HgU. ► Independent risk factor of LVDD in study group included higher BMI and lower HDL. ► Occupational exposure to Hg may be linked to LVDD.
This work is aimed at the determination of the level of molecules of intercellular adhesion of sICAM-1 and sVCAM-1 in the persons exposed to mercury. All the examined persons (88 males of 31-62) were ...divided into three groups: the persons with the diagnosis of chronic mercury intoxication in the postponed postcontact period (1st group); the persons with the first revealed diagnosis (2nd group); the persons without professional disease working under harmful conditions for more than 5 years. Determination of the molecules was conducted using immune-enzymatic analysis method. The levels of sICAM-1 didn't differ in the 1st and 2nd groups and came to 466,2 and 430,2 ng/ml respectively, the level of sICAM-1 in the 3rd group was 219,1 ng/ml. The sVCAM-1 concentration was 337,8,126,8 and 327,4 ng/ml in the 1st, 2nd and 3rd group respectively. Increasing sVCAM-1 levels in the workers with long-term work period indicate the activation of endothelial vessel. Increased levels of sICAM-1 in patients with cardiovascular disease are related to the pathogenesis of cardiovascular disease or chronic mercury intoxication.
The aim of the study was to develop a sampling method aimed at individual sampling of mercury vapor and subsequent individual exposure assessment of the worker. Hopcalite available from ...Inowrocławskie Zakłady Chemiczne (in Poland) was found useful for mercury vapor sampling in active and passive individual samplers. However the sampling rate determined for passive sampler in steady-state laboratory chamber cannot be used under fluctuating conditions of mercury vapor concentration and air movement typical for field measurement. In order to check comparativeness of passive and active sampling methods, samples were taken in the same time and individual samplers fixed to worker's clothes were used. Mercury vapor concentration was measured at two chloralkali industries in Poland and the results were presented. Excessive exposure in both industries was confirmed by finding elevated mercury concentration in urine samples from the workers.
Study was conducted in a group of 32 persons engaged in liquid phase epitaxial growth of mercury cadmium telluride (MCT) layers for nearly 11 years. Airborne mercury concentrations in work ...environment have been exceeding the threshold limit value of 0.05mg/m3 recommended by ACGIH1). Hg concentration in workplace during peak working hours remained between 0.04-0.08mg/m3. Findings were compared with 32 unexposed referents. Mercury value was estimated 1.60±0.20 (mean±SD) in control, and in Phase I and II, 10.72±1.34ng Hg/ml and 8.08±1.15ng Hg/ml of blood respectively. Results indicate a fall in blood mercury level during the second phase of study. But the values did not return to normal even after a gap of 3 months. An individual who met with a mercury accident showed 226ng Hg/ml of blood which decreased to 25ng/ml after 3 months. It is inferred from the present study that Hg level has increased significantly in MCT workers during working period, and also in non-working period, the values were higher than controls.
Elemental mercury (Hg degrees) in urine samples from workers in thermometer manufacturing factories was determined. In a factory in which the mercury level in the ambient air averaged more than 0.1 ...mg Hg m-3, the Hg degree concentration in the workers' urine ranged between 0.05 and 1.7 micrograms Hg 1(-1) and constituted less than 1% of the inorganic mercury (In-Hg) in urine. Higher amounts of Hg degrees could be detected in urine on the day of the filling operation when thermometer blanks were filled with metallic mercury and on the following day when compared with other days. During this operation, the workers were exposed to mercury vapor levels with as much as 0.47-0.67 mg Hg m-3. Our findings suggest that Hg degrees appears in urine quite rapidly after the worker's exposure to unusually high mercury levels.
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