Abstract-Ebullition, the release of gas from anaerobic decomposition in sediments, was recorded in a mercury-contaminated depositional zone (Zone 1) of the St. Lawrence River Area of Concern in Cornwall, Ontario, Canada. The aim of the present study was to test if this disturbance affected the bioavailability of total mercury (THg) and methylmercury (MeHg) in surficial sediments to a benthic invertebrate (Echinogammarus ischnus). Ebullition rates ranged from <1 to 2,800 ml/m 2 daily, with methane gas comprising 29 to 84% of the total. No direct effects of ebullition were found on either abiotic (sediment or pore water THg or MeHg concentrations) or biotic (amphipod THg or MeHg concentrations) variables measured. Instead, amphipod MeHg concentrations were best predicted by pore water THg and MeHg concentrations, organic matter of surficial sediments, and water depth and location. Trend surface analyses demonstrated that a shallow, southwestern part of Zone 1 was most contaminated with pore water mercury, which decreased in a gradient toward the northeast. Further study is needed to determine if the amount of sediment resuspended by ebullition affects the spatial distribution of mercury. Environ. Toxicol. Chem. 2013;32:857-865. # 2013 SETAC

A novel method for treating type II odontoid fractures is presented. The use of a sintered titanium odontoid prosthetic could eliminate long healing times associated with external fixation methods, and the neurological deficits associated with non-union events in odontoid fracture treatment. Finite element experiments provide early indications that the axis vertebral body could accommodate a titanium odontoid prosthetic. Strain of 3.5 % and stresses of up to 10.5 MPa on the reamed opening of the axis vertebral body are considered as the local maximums. Conventional and emerging implant fixation and non-fouling techniques are also discussed.

A single camera system for measuring ebullition from freshwater gassy sediments is presented. The employment of relatively inexpensive video equipment along with laboratory-based analysis techniques were evaluated for use in quantifying ebullition from freshwater gassy sediments in the St. Lawrence River near Cornwall, ON.