Placental metal concentrations and birth outcomes: The Environment and Childhood (INMA) project

Objective

To examine the association of placental levels of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), manganese (Mn), and chromium (Cr) with birth outcomes (birth weight, length, and head circumference, low birth weight [LBW], gestational age, preterm delivery, and small for gestational age [SGA]) in mother-child pairs from the Environment and Childhood (INMA) Project in Spain.

Reference measurements of mercury species in seafood using isotope dilution inductively coupled plasma mass spectrometry

Species-specific isotope dilution inductively coupled plasma mass spectrometry (SS ID ICP-MS) and high-performance liquid chromatography (HPLC) were used to obtain accurate and SI traceable results for methyl mercury in seafood samples such as clam, oyster and fish homogenate. The mass fractions of (62.3 ± 2.3) μg kg⁻¹, (5.44 ± 0.36) μg kg⁻¹ and (531 ± 19) μg kg⁻¹ were obtained for MeHg (as Hg) in IAEA-461, IAEA-470 and IAEA-476, respectively. Direct isotope dilution mass spectrometry was performed for total mercury content then the content of inorganic mercury in selected samples was obtained by calculation. It was found that the content of inorganic Hg in IAEA-461, IAEA-470, and IAEA-476 was as: 328 μg kg⁻¹, 16 μg kg⁻¹, and 62 μg kg⁻¹, respectively. Mathematical modelling of analytical procedure and evaluation of all parameters influencing final results were adequate for validation of measurement procedure, establishing traceability and estimating expanded uncertainty. Developed procedures were successfully applied in the characterization process of fish homogenate candidate reference material and in the calculation of assigned values in the frame of IAEA-476 inter-laboratory comparison study. Compatibility between obtained results and those derived from the certification campaign, organized by International Atomic Energy Agency on the same sample matrix (<2.6 % difference) further validated performed ID ICP-MS protocols.     

Acute exposure of mercury chloride stimulates the tissue regeneration program and reactive oxygen species production in the Drosophila midgut

We used Drosophila as an animal model to study the digestive tract in response to the exposure of inorganic mercury (HgCl₂). We found that after oral administration, mercury was mainly sequestered within the midgut. This resulted in increased cell death, which in turn stimulated the tissue regeneration program, including accelerated proliferation and differentiation of the intestinal stem cells (ISCs). We further demonstrated that these injuries correlate closely with the excessive production of the reactive oxygen species (ROS), as vitamin E, an antioxidant reagent, efficiently suppressed the HgCl₂-induced phenotypes of midgut and improved the viability. We propose that the Drosophila midgut could serve as a suitable model to study the treatment of acute hydrargyrism on the digestive systems.     

Organic and Inorganic Mercury in Biological Samples of Flouresecent Lamp Industries Workers and Health Risks

Objective The present study aims to investigate the concentrations of Hg and its aspects methyl mercury(Me-Hg) and inorganic mercury(I-Hg) in the biological samples(BSs) of fluorescent lamp industries workers(FLIWs).Methodology Different BSs including red blood cells(RBCs),plasma,urine,hair and nails were collected from the workers exposed to Hg and unexposed persons were selected as control group to measure both the T-Hg concentration as well as its species in different biological samples through quantitative analysis.Health data was collected through questionnaire survey.Results The mean concentrations of T-Hg(31.9 μg/L),Me-Hg(27.7 μg/L),and I-Hg(5.36 μg/L) in RBCs were found significantly(P 0.001) higher among the workers(n = 40) as compared to the control group(n = 40).Similarly the mean Hg concentrations in plasma,urine,hair and nails were also significantly higher among the workers than the control group.The statistical relation between Hg concentration and demographic characteristics observed that workers experience and fish consumption has increased the Hg concentration while age,weight and smoking found no significant effect on Hg concentration in the BSs.Conclusion The study observed that the workers were highly exposed to high concentration of Hg and they are at a high health risk.     

Interfacial properties of hypoxanthine adsorbed at the mercuryelectrolyte interface

The adsorption of hypoxanthine on a mercury electrode from sulfate solutions 0.2 and 0.5 M at pH 2.0 and 5.0 is studied. Differential capacity, zero charge potential and maximum surface tension measurements are used to establish the characteristics of the dilute layer. Condensed film formation is reported for first time, detected from differential capacity data at high hypoxanthine concentrations in solutions at pH 5.0. The data for the dilute layer conform to a Frumkin isotherm, contrary to previous findings about a Langmuir isotherm. The data are also analysed following the Nikitas approach and a value for the size ratio parameter close to one is obtained. The discussion in terms of Esin-Markov effect and electrosorption valency in comparison with other aromatic compounds allows some conclusions to be drawn about the orientation of the molecule, the role played by electrostatic and π-electron interactions and the effect of intermolecular interactions.     

The effects of amalgam restorations on plasma mercury levels and total antioxidant activity

Objective

This study evaluated the effects of amalgam restorations on plasma mercury levels and total antioxidant activities (TAA).

Design

The study was comprised of 48 subjects ranging in age from 20 to 32 years. Of these, 33 had dental amalgam restorations and 15 had no dental amalgam restorations. In those patients with amalgams, the total number of amalgam restorations and surfaces were counted, and the total and occlusal areas (mm²) of restorations were measured using a Counting Measurement Machine. Blood samples were collected from all participants. Plasma mercury levels were measured using an Atomic Absorption Spectrometer and Hydride System, and plasma TAA levels were measured using an Antioxidant Assay Kit. Statistical analysis was performed using the SPSS 10.01 software program. Data was evaluated by t test and correlation analysis.

Results

Plasma mercury (P-Hg) levels were found to be significantly higher in subjects with amalgam restorations when compared to subjects without amalgams (p < 0.01); the differences in P-TAA levels between subjects with and without amalgams were not found to be statistically significant (p > 0.05). No significant correlations were found between P-Hg concentrations and P-TAA levels (p > 0.05). Significant positive correlations were found between P-Hg concentrations and the number of amalgam restorations (p < 0.01), number of amalgam surfaces (p < 0.05), total amalgam surface area (p < 0.05) and amalgam occlusal surface area (p < 0.01). However, no significant correlations were found between these parameters and P-TAA (p > 0.05).

Conclusions

The results of our study showed that dental amalgams are a major source of plasma mercury; however, amalgam restorations were not found to have a significant effect on plasma-total antioxidant activities.     

Biomonitoring of mercury and persistent organic pollutants in Michigan urban anglers and association with fish consumption

The 32-mile Detroit River and surrounding tributaries have been designated as a Great Lakes Area of Concern due to pollution from decades of municipal and industrial discharges, sewer overflows and urban development. Key pollutants in fish samples from the Detroit River include mercury, polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), dioxins and furans. A biomonitoring study was conducted to assess exposures to these persistent toxic substances in Detroit urban shoreline anglers who may be at high exposure risk due to consumption of locally caught fish. Using a modified venue-based sampling approach, 287 adult shoreline anglers along the Detroit River were recruited and participated in the program. Study participants provided blood and urine specimens and completed a questionnaire following informed consent. We examined percentile estimates for total blood mercury, PCBs, DDE, and dioxin-like total toxic equivalency (TEQ) concentrations among study participants. Multiple linear regression was used to identify important predictors of contaminant concentrations. Participants consumed a median of 64 Detroit River caught fish meals in the past year. The Detroit urban anglers’ median total blood mercury concentrations was 3.2 times higher than that for the general adult U.S. population. PCB concentrations among the Detroit anglers aged 18–39 years were higher than the U.S. population of the same race/ethnicity. Elevated levels of DDE and total TEQ concentrations were not observed in the cohort. Eating more locally caught fish was associated with higher total blood mercury and serum PCB concentrations. The biomonitoring data served to inform public health officials and help guide environmental public health actions to reduce harmful exposures.     

Hair mercury concentrations and in vitro fertilization (IVF) outcomes among women from a fertility clinic

Total hair mercury (Hg) was measured among 205 women undergoing in vitro fertilization (IVF) treatment and the association with prospectively collected IVF outcomes (229 IVF cycles) was evaluated. Hair Hg levels (median = 0.62 ppm, range: 0.03–5.66 ppm) correlated with fish intake (r = 0.59), and exceeded the recommended EPA reference of 1 ppm in 33% of women. Generalized linear mixed models with random intercepts accounting for within-woman correlations across treatment cycles were used to evaluate the association of hair Hg with IVF outcomes adjusted for age, body mass index, race, smoking status, infertility diagnosis, and protocol type. Hair Hg levels were not related to ovarian stimulation outcomes (peak estradiol levels, total and mature oocyte yields) or to fertilization rate, embryo quality, clinical pregnancy rate or live birth rate.     

慢性汞中毒致神经系统损害的临床观察

目的 分析慢性汞中毒对患者神经系统损害的表现,以提高对慢性汞中毒的临床认识.方法 总结分析2006--2010年首都医科大学宣武医院神经内科收治的8例慢性汞中毒患者的临床资料.结果 慢性汞中毒造成的神经系统损害包括周围神经病变以及感觉异常(6/8例)、思维缓慢及精神异常(3/8例)、肢体无力萎缩(3/8例)、震颤(4/8例)、睡眠障碍(3/8例)等.结论 慢性汞中毒可以有各种各样的神经系统损害的表现,在临床工作中要注意鉴别.尽早诊治会减少患者痛苦.     

Oral exposure to cadmium and mercury alone and in combination causes damage to the lung tissue of Sprague-Dawley rats

Environmental presence and human exposure to heavy metals in air and cigarette smoke has led to a worldwide increase in respiratory disease. The effects of oral exposure to heavy metals in liver and kidney structure and function have been widely investigated and the respiratory system as a target is often overlooked. The aim of the study was to investigate the possible structural changes in the lung tissue of Sprague-Dawley rats after oral exposure for 28 days to cadmium (Cd) and mercury (Hg), alone and in combination at 1000 times the World Health Organization’s limit for each metal in drinking water. Following exposure, the general morphology of the bronchiole and lungs as well as collagen and elastin distribution was evaluated using histological techniques and transmission electron microscopy. In the lungs, structural changes to the alveoli included collapsed alveolar spaces, presence of inflammatory cells and thickening of the alveolar walls. In addition, exposure to Cd and Hg caused degeneration of the alveolar structures resulting in confluent alveoli. Changes in bronchiole morphology included an increase in smooth muscle mass with luminal epithelium degeneration, detachment and aggregation. Prominent bronchiole-associated lymphoid tissue was present in the group exposed to Cd and Hg. Ultrastructural examination confirmed the presence of fibrosis where in the Cd exposed group, collagen fibrils arrangement was dense, while in the Hg exposed group, additional prominent elastin was present. This study identified the lungs as target of heavy metals toxicity following oral exposure resulting in cellular damage, inflammation and fibrosis and increased risk of respiratory disease where Hg showed the greatest fibrotic effect, which was further, aggravated in combination with Cd.