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The environmental cycling of mercury (Hg) can be affected by natural and anthropogenic perturbations. Of particular concern is how these disruptions increase mobilization of Hg from sites and alter the formation of monomethylmercury (MeHg), a bioaccumulative form of Hg for humans and wildlife. The scientific community has made significant advances in recent years in understanding the processes contributing to the risk of MeHg in the environment. The objective of this paper is to synthesize the scientific understanding of how Hg cycling in the aquatic environment is influenced by landscape perturbations at the local scale, perturbations that include watershed loadings, deforestation, reservoir and wetland creation, rice production, urbanization, mining and industrial point source pollution, and remediation. We focus on the major challenges associated with each type of alteration, as well as management opportunities that could lessen both MeHg levels in biota and exposure to humans. For example, our understanding of approximate response times to changes in Hg inputs from various sources or landscape alterations could lead to policies that prioritize the avoidance of certain activities in the most vulnerable systems and sequestration of Hg in deep soil and sediment pools. The remediation of Hg pollution from historical mining and other industries is shifting towards in situ technologies that could be less disruptive and less costly than conventional approaches. Contemporary artisanal gold mining has well-documented impacts with respect to Hg; however, significant social and political challenges remain in implementing effective policies to minimize Hg use. Much remains to be learned as we strive towards the meaningful application of our understanding for stakeholders, including communities living near Hg-polluted sites, environmental policy makers, and scientists and engineers tasked with developing watershed management solutions. Site-specific assessments of MeHg exposure risk will require new methods to predict the impacts of anthropogenic perturbations and an understanding of the complexity of Hg cycling at the local scale.

Background:
In the present study, the antimicrobial properties of a new ozonized olive oil (O-zone gel) against oral and periodontal pathogens will be evaluated and compared with that of common CHX-based agents.

Material and Methods:
O-zone gel was compared with two agents based on chlorhexidine digluconate (CHX): Corsodyl Dental Gel and Plak Gel. A. actinomycetemcomitans, P. intermedia and S. mutans, were selected and the antibacterial capability of the compounds was tested by using direct contact agar diffusion test (DCT) and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) evaluations. Differences between specific means were analyzed by a one-way analysis of variance (ANOVA). Group means were compared using a one-way ANOVA and Tukey’s test (P<0.05).

Results:
O-zone gel reported inhibition zones which correspond to 33% and 43% of that achieved by the CHX agents. No inhibition of bacterial growth (MIC) on the Gram-positive strain by using O-zone gel was found and no antimicrobial effect (MBC) was observed by using O-zone gel on both Gram-negative and -positive strains.

Conclusions:
The new ozonated oil was a relatively moderate antiseptic. Gram-negative bacteria proved to be more sensitive to ozonized olive oil than Gram-positive ones. The ozonized olive oil demonstrated a lower antibacterial activity if compared to the CHX-based agents tested.

Mercury is a well-known toxic element that is found in various forms in nature. Recently, dental amalgams have been recognized as a new source of mercury. This study was carried out under in vitro condition; the amount of mercury released from teeth restored with amalgams in the presence of Wi-Fi router radiation (non-ionizing radiation) and X-ray (ionizing radiation) using a protocol similar to Computed Tomography of Para-nasal Sinuses (CT) were analyzed separately, and in combination on the samples. For this reason, 50 human premolars were restored with a certain type of commercial amalgams. The samples were divided into five groups; control, only-CT, CT+Wi-Fi, Wi-Fi+CT and only-Wi-Fi groups, and mercury measurement were investigated at 24 and 48 hours after exposure to radiation by cold-vapor atomic absorption system. The results showed a significant difference between subgroups 24 and 48 h (p-values = 0.001 and 0.008). However, over time a significant difference was only found in CT+Wi-Fi group (p-value = 0.043). In addition, in comparison with the control group, only the subgroup that was exposed to Wi-Fi waves showed a significant difference after 24 hours (p = 0.033). In line with some of the previous studies, our findings showed that electromagnetic waves are involved in mercury release process, and warnings about the consequences of electromagnetic waves on mercury release and subtitling it with a new compound in restorative dentistry should be taken into consideration.

Abstract
OBJECTIVES:
The aim was to gain knowledge regarding the risk of perinatal death related to exposure to dental amalgam fillings in the mother.

DESIGN:
Population-based observational cohort study.

SETTING:
The Norwegian Mother and Child Cohort Study, a Norwegian birth cohort of children born in 1999-2008 conducted by the Norwegian Institute of Public Health.

PARTICIPANTS:
72,038 pregnant women with data on the number of teeth filled with dental amalgam.

MAIN OUTCOME MEASURES:
Data on perinatal death (stillbirth ≥ 22 weeks plus early neonatal death 0-7 days after birth) were obtained from the Medical Birth Registry of Norway.

RESULTS:
The absolute risk of perinatal death ranged from 0.20% in women with no amalgam-filled teeth to 0.67% in women with 13 or more teeth filled with amalgam. Analyses including the number of teeth filled with amalgam as a continuous variable indicated an increased risk of perinatal death by increasing number of teeth filled with dental amalgam (crude OR 1.065, 95% CI 1.034 to 1.098, p<0.001). After adjustment for potential confounders (mothers’ age, education, body mass index, parity, smoking during pregnancy, alcohol consumption during pregnancy) included as categorical variables, there was still an increased risk for perinatal death associated with increasing number of teeth filled with amalgam (ORadj 1.041, 95% CI 1.008 to 1.076, p = 0.015). By an increased exposure from 0 to 16 teeth filled with amalgam, the model predicted an almost doubled odds ratio (ORadj 1.915, 95% CI 1.12 to 3.28). In groups with 1 to 12 teeth filled with amalgam the adjusted odds ratios were slightly, but not significantly, increased. The group with the highest exposure (participants with 13 or more teeth filled with amalgam) had an adjusted OR of 2.34 (95% CI 1.27 to 4.32; p = 0.007).

CONCLUSION:
The current findings suggest that the risk of perinatal death could increase in a dose-dependent way based on the mother’s number of teeth filled with dental amalgam. However, we cannot exclude that the relatively modest odds ratios could be a result of residual confounding. Additional studies on the relationship between exposure to dental amalgam fillings during pregnancy and perinatal death are warranted.