Toxicity of Weathered Sediment-Bound Dilbit to Early Life Stages of Zebrafish (Danio rerio).

Due to high viscosity, bitumen extracted from the Alberta oil sands is diluted with natural gas condensates to form diluted bitumen (dilbit) to facilitate transport through pipelines. Dilbit that is spilled into or near a waterbody is subject to environmental weathering processes such as evaporation and interaction with sediments. This is the first study that assessed the toxicity of weathered sediment-bound dilbit (WSD) to fish early life stages. Exposure of zebrafish (Danio rerio) embryos to water-soluble fractions (WSFs) or water-accommodated fractions (WAFs) of WSD from 30 min to 120 h postfertilization resulted in pericardial edema, yolk sac edema, and incidences of uninflated swim bladder. The presence of oil-mineral aggregates (OMAs) in the WAFs greatly increased toxicity, despite all fractions having similar concentrations of dissolved polycyclic aromatic hydrocarbons (PAHs). There were greater cyp1a mRNA abundances in larvae exposed to WAFs, suggesting that there were differences in bioavailability of PAHs between fractions. However, there was little evidence that embryotoxicity was caused by oxidative stress. Results suggest that evaporation and sediment interaction do not completely attenuate toxicity of dilbit to zebrafish early life stages, and OMAs in exposures exacerbate toxicity.

Child Sexual Abuse Documentation in Primary Care Settings.

Primary care providers (PCPs) can play an important role in the continuity of care for children who experience sexual abuse (SA). We performed a retrospective, chart-based study of children 3 to 17 years old with SA history. Primary care medical records were reviewed for 2 years after a subspecialty SA evaluation. Descriptive statistics and logistic regression were used to assess factors associated with documentation of SA history and mental health management by the PCP. Of 131 included patients, 43% had PCP documentation of their SA history, which was associated with care from resident providers (P < .01). There was greater mental health management and mental health referrals by PCPs for the group with documentation compared with the group without documentation (52% vs 23%, P < .001). Overall, child SA history was poorly documented in primary care settings. Identifying mechanisms to improve communication about a child's SA history with PCPs is important for the child's ongoing care.

Effects of weathered sediment-bound dilbit on freshwater amphipods (Hyalella azteca).

Bitumen mined in the oil sands region of Northern Alberta, Canada, is diluted with natural gas condensates to form dilbit, which is transported through pipelines. Sections of these pipelines come close to freshwater ecosystems. If dilbit is spilled into or near an aquatic environment, environmental weathering processes, such as evaporation and sediment interaction, influence the fate and toxicity of dilbit to aquatic organisms. To date, most studies of the effects of dilbit on the health of aquatic organisms have not considered weathering processes. Thus, the goal of this study was to assess the toxicity of weathered sediment-bound dilbit (WSD) to an aquatic organism. Adult freshwater amphipods (Hyalella azteca) were exposed directly to WSD or the water-soluble fraction (WSF) of WSD. Direct exposure to WSD resulted in oil-mineral aggregates adhering to the appendages and gas exchange structures of amphipods, causing acute lethality. After a 10-min exposure to WSD, amphipods consumed half as much oxygen and their appendage movement was impaired. Exposure to the WSF, which contained a total PAH concentration of 1.08 µg/L, did not result in acute lethality, or significantly affect respiration, activity or acetylcholinesterase activity. Results of the present study indicate that physical interaction with oil-mineral aggregates after a spill of dilbit is a threat to benthic invertebrates, whereas the WSF does not cause acute adverse effects. As the transport of dilbit through pipelines increases in North America, studies must incorporate environmental weathering processes when determining the effects of dilbit on aquatic organisms.