Evaluating the performance of diffusive gradients in thin films for predicting Ni sediment toxicity.

Diffusive gradients in thin films (DGTs) rapidly measure labile fractions of metal and are promoted as an assessment tool for bioavailability. Using macroinvertebrate community composition as a response, this study compared the predictive ability of DGT-measured Ni with acid volatile sulfide (AVS) and organic carbon (OC) corrected Ni [(SEM(Ni)-AVS)/f(OC)] and total Ni concentrations. In two experiments, sediments were amended with Ni and placed within either a streamside mesocosm or deployed in situ.

A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 1: System description and proof of concept.

In situ-based testing using aquatic organisms has been widely reported, but is often limited in scope and practical usefulness in making decisions on ecological risk and remediation. To provide this capability, an integrated deployment system, the Sediment Ecotoxicity Assessment (SEA) Ring was developed, which incorporates rapid in situ hydrological, chemical, bioaccumulation, and toxicological Lines-of-Evidence (LoE) for assessing sediment and overlying water contamination. The SEA Ring system allows for diver-assisted, or diverless, deployment of multiple species of ecologically relevant and indigenous organisms in three different exposures (overlying water, sediment-water interface, and bulk sediment) for periods ranging from two days to three weeks, in a range of water systems.

A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 2: Integrated application to a shallow estuary.

A comprehensive, weight-of-evidence based ecological risk assessment approach integrating laboratory and in situ bioaccumulation and toxicity testing, passive sampler devices, hydrological characterization tools, continuous water quality sensing, and multi-phase chemical analyses was evaluated. The test site used to demonstrate the approach was a shallow estuarine wetland where groundwater seepage and elevated organic and inorganic contaminants were of potential concern. Although groundwater was discharging into the surficial sediments, little to no chemical contamination was associated with the infiltrating groundwater.

Effects of suspended solids and dissolved organic carbon on nickel toxicity.

Nickel (Ni) is a common and potentially toxic heavy metal in many fluvial ecosystems. We examined the potentially competitive and complementary roles of suspended sediment and a dissolved organic ligand, humate, in affecting the partitioning and toxicity of Ni to a model organism, Daphnia magna, in both batch and stream-recirculating flume (SRF) tests. Sediments included a fine-grained deposit, montmorillonite, and kaolinite.

Orbital myositis after upper respiratory tract infection.

Two cases of isolated unilateral extraocular muscle myositis after antecedent upper respiratory tract infections are reported. Pain, inflammation over the involved muscle, restricted motility, and an enlarged muscle on computerized axial tomography scan are the findings. This is differentiated from conjunctival inflammatory disease and neurologic disorders.