A benchmark concentration analysis for manganese in drinking water and IQ deficits in children.

Background: Manganese is an essential nutrient, but in excess, can be a potent neurotoxicant. We previously reported findings from two cross-sectional studies on children, showing that higher concentrations of manganese in drinking water were associated with deficits in IQ scores. Despite the common occurrence of this neurotoxic metal, its concentration in drinking water is rarely regulated.

Radium geochemical monitoring in well waters at regional and local scales: an environmental impact indicator-based approach.

To assess radium (Ra) as a potential indicator of impact in well waters, we investigated its behavior under natural conditions using a case study approach. Ra geochemistry was investigated in 67 private wells of southeastern New Brunswick, Canada, a region targeted for potential shale gas exploitation. Objectives were to i) establish Ra baseline in groundwater; ii) characterize Ra spatial distribution and temporal variability; iii) characterize Ra partitioning between dissolved phase and particulate forms in well waters; and iv) understand the mechanisms controlling Ra mobility under natural environmental settings.

Assessment of saliva, hair and toenails as biomarkers of low level exposure to manganese from drinking water in children.

We evaluated hair, toenails, and saliva (whole and supernatant) as biomarkers of exposure to manganese (Mn) in 274 school age children (6-13 years) consuming well water in southeastern New Brunswick, Canada. Mn concentrations in tap water ranged from <0.03 to 1046μgL (geometric mean 5.

Exposure to low environmental concentrations of manganese, lead, and cadmium alters the serotonin system of blue mussels.

Serotonin plays a crucial role in mussel survival and reproduction. Although the serotonin system can be affected by metals, the effects of environmental concentrations of metals such as manganese (Mn), lead (Pd), and cadmium (Cd) have never been studied in blue mussels. The present study aimed to determine the effects of exposure to Mn, Pb, or Cd on serotonin levels, monoamine oxidase (MAO) activity, and serotonin transporter (SERT) levels in the blue mussel Mytilus edulis.

Low level exposure to manganese from drinking water and cognition in school-age children.

Background: Manganese (Mn) is an element found in the environment and certain geographic areas have elevated concentrations in soil and water du to natural conditions or anthropic activities. A growing body of data suggests that exposure to manganese in drinking water could be neurotoxic.

Objective: Firstly, we aimed to examine the association between exposure to manganese from drinking water and cognition in children consuming well water.

Quantification of Ra at environmental relevant levels in natural waters by ICP-MS: Optimization, validation and limitations of an extraction and preconcentration approach.

Radium (Ra) at environmental relevant levels in natural waters was determined by ICP-MS after an off-line pre-concentration procedure. The latter consisted of Ra selective elution from potential interfering elements (i.e.

Sex determination in blue mussels: Which method to choose?

Sexing methods of blue mussels are mostly based on the presence or absence of gametes, and do not take into account reproductive cycle stages. Exposure effects can be affected by the sex of mussels, thus the aim of this study is to determine an efficient sex determination protocol taking into account the reproductive cycle stage. Eight mussel sexing methods were compared.

Fish and seafood availability in markets in the Baie des Chaleurs region, New Brunswick, Canada: a heavy metal contamination baseline study.

The consumption of halieutic products has many health benefits. However, their contaminants loads need to be addressed to better understand the risk from consuming these products. The aquatic biota from the Baie des Chaleurs in New Brunswick is contaminated by cadmium, zinc and lead.

Spatial and temporal distribution of heavy metal concentrations in mussels (Mytilus edulis) from the Baie des Chaleurs, New Brunswick, Canada.

Previous studies on heavy metal contamination of the Baie des Chaleurs focus only on industrial centers and overlooked the ecosystem as a whole. To fill this gap, the objective of this study is to establish a baseline of the spatio-temporal distribution of heavy metals in mussels from the Baie des Chaleurs based on the ecosystem approach. Our results show, for the first time, a cadmium contamination in mussels across the south coast of the Baie des Chaleurs and not only in industrial centers.

Characterization of bacterial and fungal communities in composted biosolids over a 2 year period using denaturing gradient gel electrophoresis.

Composting is a microbial process that converts organic waste into a nutrient-rich end product used in horticultural and agricultural applications. The diversity and long-term succession of microorganisms found in composted biosolids has been less characterized than other composts. In this study, bacterial and fungal communities found in composted biosolids aging from 1 to 24 months were studied using denaturing gradient gel electrophoresis (DGGE) and sequencing.

Quantification of Salmonella spp. in composted biosolids using a TaqMan qPCR assay.

Composting is increasingly used to transform biosolids, obtained following wastewater treatment, into a more stable organic product that can be released in the environment. The process must however be closely monitored to assure that the end product meets the regulations set by environmental agencies with regards to the amount of pathogenic microorganisms present. In this study, a TaqMan qPCR approach targeting the invA gene was developed to monitor the presence of Salmonella spp.

Influence of intensive fishing on the partitioning of mercury and methylmercury in three lakes of Northern Québec.

It has been demonstrated that intensive fishing, i.e., removing more than 25% of the fish biomass, can reduce mercury levels in predator fish in a lake.