Selenium and mercury in freshwater fish muscle tissue and otoliths: a comparative analysis.

Evaluating potential ecological and human health risks of exposure to bioaccumulative trace elements is typically implemented using analysis of tissue samples. Increasingly, the microchemistry of fish calcified structures is used to elucidate the lifetime exposure to trace elements. In the present study, we measured total mercury (THg), methylmercury (MeHg), and selenium (Se) in muscle tissue and otolith samples from 12 species of fish collected at reference sites and locations influenced by power plant wastewater. Muscle tissue concentrations of Se were sensitive to recent wastewater exposure magnitude, stream type, trophic level, and species (p < 0.001). For Hg, concentrations in muscle tissue and otoliths were affected only by trophic level and species. Levels of THg and Se in muscle tissue and otolith samples were positively correlated for those species with a robust sample size. Some individual fish from 3 species (channel catfish, hybrid striped bass, and freshwater drum) showed significantly increasing or decreasing lifetime concentrations of either THg or Se in otolith samples. Multiple regression analysis indicated that for bluegill muscle tissue Se concentrations could be best explained utilizing water concentrations of selenium, sulfate, and molybdenum (r2 = 0.87; p < 0.001). Because of the increased cost and specialized sample processing requirements of analyzing trace elements in otolith structures, it may be prudent to limit these analyses to those species where insights into temporal trends are sought or where evidence indicates that fish move into or out of contaminated water bodies. Environ Toxicol Chem 2019;38:1467-1475. © 2019 SETAC.

Microchemical analysis of selenium in otoliths of two West Virginia fishes captured near mountaintop removal coal mining operations.

Otoliths, calcified inner ear structures, were collected from creek chubs (Semotilus atromaculatus) and green sunfish (Lepomis cyanellus) living in mountaintop mining-impacted and reference streams and analyzed for selenium (Se) content using laser ablation-inductively coupled mass spectrometry. Significant differences in otolith Se were found between the 2 fish species. Results from the present study suggest that a retrospective reconstruction of Se concentrations in muscle can be derived from Se concentrations in otoliths in creek chub but not green sunfish, exemplifying the importance of species differences when determining partitioning of Se among specific tissues. Green sunfish otoliths from all sites contained background (<1 µg/g) or low (1-4 µg/g) average concentrations of whole-otolith Se. In contrast, creek chub otoliths from the historically mined site contained much higher (≥5 µg/g) concentrations of Se than for the same species in the unmined site or for the green sunfish. These data suggest that body burdens of Se in fish can vary considerably over time and that both the timing of sampling and species choice could heavily influence Se assessments.

Being a seasoned nurse in active practice.

AIM: The purpose of this qualitative study was to discover what rewards and inspires seasoned nurses to continue to practice in acute care after the normal age of nurse retirement, and to identify best practices in retention. BACKGROUND: An aging population and an aging nursing workforce are twin issues that bring urgency to this issue. Seasoned nurses have much to contribute to the workforce, but very few studies have examined strategies to retain them. METHODS: A grounded theory approach was used in two phases to explore the meaning of being a seasoned nurse. In phase 1, 13 nurses over the age of 62 years were queried about the meaning of being a seasoned nurse actively engaged in acute care nursing. The second phase included 12 nurses in active practice anticipating retirement (aged 55-62 years). Semi-structured interviews were conducted, audiotaped, transcribed and analysed. RESULTS: A concept map with four major themes emerged from the data. The themes were identified as (1) pre-existing attitudes and experiences, (2) retention factors, (3) important needs, and (4) unique contributions. CONCLUSIONS: Seasoned nurses enjoy, and engage in, nursing and derive benefits from continued practice. Further research is needed to determine the relative importance of the factors identified as important to nurses as they anticipate, and experience, retirement. IMPLICATION FOR NURSE MANAGERS: An understanding of these factors can be used to aid nursing leaders to retain seasoned nurses in practice beyond retirement age.

Exposure histories derived from selenium in otoliths of three cold-water fish species captured downstream from coal mining activity.

Establishing exposure to contaminants within a given environment is often difficult for fish species with large home ranges. Chemical analyses of muscle or visceral tissue are useful indicators of recent exposure, but depuration, metabolic transformation, and tissue redistributions can alter temporal resolution. Otoliths are metabolically stable and thus provide complete chemical records within their calcified tissues that, when coupled to the annular structure, can provide temporal resolution for exposure to trace metals. Otoliths from bull trout, cutthroat trout, and mountain whitefish from an area rich in seleniferous soils and with active coal mining activity were analyzed for selenium to determine any history of exposure to elevated levels of selenium. Selenium concentrations in otolith primordia tended to be low, indicating that these fish emerged in low selenium areas. Later life stages showed peaks of high Se concentrations, suggesting that individuals moved into areas of increased selenium later in life. Individuals captured from the same area had a wide variety of selenium exposure profiles, indicating that these fish do not move en masse into and out of high-selenium areas. Year-to-year variability of selenium exposure patterns within an otolith suggests inconsistent utilization of high- and low-selenium areas by the individual. The inconsistent exposure profiles for these fish, in addition to their home range of tens of kilometres, indicate that soft tissue concentrations, while useful indicators of recent exposure, cannot be relied upon to provide a life history recording of exposure.

Pilot testing an educational intervention to improve communication with patients with dementia.

Approximately one quarter of all hospitalized patients over age 75 years have a secondary diagnosis of dementia. A unique hospital-wide program to encourage appropriate communication techniques with patients who have dementia was provided to all departments of a hospital. Evaluation indicated improvement in some communication techniques. Additional education is needed to disperse the information to as many staff as possible and to sustain the change.

Laser ablation inductively coupled plasma mass spectrometric analyses of base metals in arctic char (Salvelinus alpinus) otoliths collected from a flooded base metal mine.

Otoliths from arctic char recovered from the water body formed from an abandoned open-pit nickel-copper mine contain a trace element record related to the geology of the immediate watershed, past mining activity in the area, and the fish's diet. Laser ablation inductively coupled plasma mass spectrometric analyses across the annular structure of the otoliths detected trace amounts of nickel, copper, and chromium believed to be related to the metal-bearing, mafic-ultramafic minerals in the pit. Oscillatory strontium, barium, and zinc profiles may reflect changing water temperature, diet, or fish metabolism. Lead was detected in very low concentrations and may be related to anthropogenic influence. This closed lake system provides a unique opportunity to study an introduced exotic species in a setting where neither migration nor recruitment have been possible. The fish have successfully occupied the lake and continue to breed despite the influence of the surrounding rocks and local contamination. The chemical record retained within otoliths provides a method of monitoring trace elements affecting fish on a yearly basis and may be regarded as a useful assessment tool for examining the exposure of wild organisms to trace elements.

The special needs of the hospitalized patient with dementia.

As the population ages, the number of patients with dementia will increase rapidly. Nurses caring for patients with dementia will need knowledge of interventions for communicating; managing agitation, nutrition, hygiene, and pain; providing spiritual care; and determining decision-making capacity.

Determining exposure history of northern pike and walleye to tailings effluence using trace metal uptake in otoliths.

Determining the effects of mining activity on fish populations is complicated by the uncertainty of fish residency in an affected area. Otoliths are considered to be metabolically inert and can contain complete chemical records of environments in which individuals have lived. When coupled with the annular structure, otoliths provide temporal information to the history of exposure to pollutants. In this preliminary study, northern pike and walleye otoliths collected from two lakes adjacent to base metal mine tailings at Lynn Lake, Manitoba, Canada, were analyzed using laser ablation inductively coupled plasma mass spectrometry to determine background levels of trace metals. The presence of overlapping Zn, Cu, and Pb peaks above background levels in some otoliths is interpreted as a record of elevated levels in the environment. These otoliths provided a record of the history of fish movement into and out of the affected area.

Value of multislice CT scan in redo cardiac surgery with previous Lita graft.

Redo cardiac surgery is commonly performed in the current era. We describe a clinical scenario in a patient with a patent left internal thoracic artery to left anterior descending artery graft, requiring replacement of ascending aortic aneurysm with previous coronary artery bypass operation complicated by mediastinitis. A pre-operative 64 slice computed tomographic scan helped us plan and perform replacement of ascending aorta safely.

Alkali element uptake in otoliths: a link between the environment and otolith microchemistry.

Otoliths taken from fish in the vicinity of rare element pegmatites in eastern Manitoba, Canada, were analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and found to contain lithium, sodium, rubidium, cesium, and strontium at levels ranging from a few ppm to a few 10s of ppm. In some otoliths, the concentrations varied in correspondence to the annular structure of the otoliths, suggesting a periodicity to their incorporation. This is the first reported detection and resolution of periodic signals of Rb and Cs in otoliths. The correspondence between the elements in the otoliths and surrounding rocks suggests there can be a strong link between the microchemistry of a fish's otoliths and its environment particularly where there are distinctive rock types. These elements may serve as natural markers in certain environments and may be used to characterize and monitor lacustrine environments over a period of time.

Development of an evidence-based protocol for reduction of indwelling urinary catheter usage.

Studies indicate 40% of indwelling urinary catheters are unnecessary in hospitalized patients (Gardam, Amihod, Orenstein, Consolacion, & Miller, 1998; Gokula, Hickner, & Smith, 2004). The results of a protocol developed to limit catheter use are described.