How does climate variability affect water quality dynamics in Canada's oil sands region?

In Canada's oil sands region, classic boreal hydrology (i.e., winter low flow followed by peaks during spring freshet and then summer flow recession) combined with erosion of both natural and anthropogenically-exposed bitumen results in seasonal and inter-annual variability in stream water chemistry. Using data collected from all seasons over three years (2012-2015), we investigated the mechanisms driving spatial and temporal change in the concentration of 26 water quality parameters for six rivers draining Canada's oil sands region. Mantel tests showed a strong spatial aggregation of climatic drivers (average daily precipitation, accumulated precipitation, snow water equivalent) associated with west versus east discharge patterns. Wavelet analysis highlighted unique watershed attributes, in particular the importance of developed area in lowering responsiveness to seasonal precipitation. Concentrations of most chemical parameters (20 of 23) showed distinct temporal patterns that were correlated with seasonal changes in hydrology which, in turn, were related to changes in weather. Comparison of concentrations observed in this study with those reported in the scientific literature for the same watersheds showed 81% of comparisons differed significantly. This was likely due to the short duration of previous field campaigns and thus the sampling of a very narrow window of the annual streamflow regime.

Effects of oil sands process water mixtures on the mayfly Hexagenia and field-collected aquatic macroinvertebrate communities

Extraction of Canada's oil sands has created 1 billion m³ of tailings, which are stored in on-site tailings ponds. Due to limited storage capacity, the planned release of tailings into the surrounding environment may be required. This represents an environmental management challenge, as the tailings contain contaminants that are known toxins to aquatic communities. Of particular concern are naphthenic acids and their metallic counterparts, as they are the principal toxic components of tailings, are relatively soluble, and are persistent in aquatic environments. This study examines the acute toxicity of environmentally relevant 10:1 mixtures of two process water components: naphthenic acid and sodium naphthenate. We assess the effects of these simplified oil sands process water (OSPW) mixtures under planned and unplanned tailings release scenarios, using traditional and cutting-edge bioindicators for aquatic invertebrate taxa. We found that safe concentrations for mayflies and other aquatic macroinvertebrates were less than 1 mg/l, as no mayfly taxa survived repeated exposure to this dose in either the 48-h or 72-h acute toxicity test. In the 72-h test, no mayflies survived treatment levels greater than 0.5 mg sodium naphthenate/l. In the mesocosm study, even a 90% dilution of the OSPW mixture was not sufficient to protect sensitive macroinvertebrate communities. The results of this study highlight the potential environmental damage that will occur if OSPW is not carefully managed. This information will aid with the development of a management plan for oil sands tailings ponds, which will provide insight into the potential for process water release into the surrounding environment while conserving unique ecosystems downstream of development in the oil sands region.

Got Milk? How Freedoms Evolved From Dairying Climates

The roots and routes of cultural evolution are still a mystery. Here, we aim to lift a corner of that veil by illuminating the deep origins of encultured freedoms, which evolved through centuries-long processes of learning to pursue and transmit values and practices oriented toward autonomous individual choice. Analyzing a multitude of data sources, we unravel for 108 Old World countries a sequence of cultural evolution reaching from (a) ancient climates suitable for dairy farming to (b) lactose tolerance at the eve of the colonial era to (c) resources that empowered people in the early industrial era to (d) encultured freedoms today. Historically, lactose tolerance peaks under two contrasting conditions: cold winters and cool summers with steady rain versus hot summers and warm winters with extensive dry periods (Study 1). However, only the cold/wet variant of these two conditions links lactose tolerance at the eve of the colonial era to empowering resources in early industrial times, and to encultured freedoms today (Study 2). We interpret these findings as a form of gene-culture coevolution within a novel thermo-hydraulic theory of freedoms.

Episodic acidification of 5 rivers in Canada's oil sands during snowmelt: A 25-year record

Episodic acidification during snowmelt is a natural phenomenon that can be intensified by acidic deposition from heavy industry. In Canada's oil sands region, acid deposition is estimated to be as much as 5% of the Canadian total and large tracks of northeastern Alberta are considered acid-sensitive because of extensive peatland habitats with poorly weathered soils. To identify the frequency, duration and severity of acidification episodes during snowmelt (the predominant hydrological period for delivery of priority pollutants from atmospheric oil sands emissions to surface waters), a 25-year record (1989 to 2014) of automated water quality data (pH, temperature, conductivity) was assembled for 3 rivers along with a shorter record (2012-2014) for another 2 rivers. Acidic episodes (pH<7, ANC<0) were recorded during 39% of all 83 snowmelt events. The severity (duration x magnitude) of episodic acidification increased exponentially over the study period (r²=0.56, P<0.01) and was strongly correlated (P<0.01) with increasing maximum air temperature and weakly correlated with regional land development (P=0.06). Concentrations of aluminum and 11 priority pollutants (Sb, As, Be, Cd, Cr, Cu, Pb, Se, Ag, Tl and Zn) were greatest (P<0.01) during low (<6.5) pH episodes, particularly when coincident with high discharge, such that aluminum and copper concentrations were at times high enough to pose a risk to juvenile rainbow trout (Oncorhynchus mykiss). Although low pH (pH<6.5) was observed during only 8% of 32 acidification episodes, when present, low pH typically lasted 10days. Episodic surface water acidification during snowmelt, and its potential effects on aquatic biota, is therefore an important consideration in the design of long-term monitoring of these typically alkaline (pH=7.72±0.05) rivers.

Emancipating Sexuality: Breakthroughs into a Bulwark of Tradition

This article presents evidence for a rising emancipatory spirit, across generations and around the world, in a life domain in which religion hitherto blocked emancipatory gains: sexual freedoms. We propose an explanation of rising emancipative values that integrates several approaches into a single idea-the utility ladder of freedoms. Specifically, we suggest that objectively improving living conditions-from rising life expectancies to broader education-transform the nature of life from a source of threats into a source of opportunities. As life begins to hold more promise for increasing population segments, societies climb the utility ladder of freedoms: practicing and respecting universal freedoms becomes increasingly vital to take advantage of rising life opportunities. This trend has begun to spill over into a life domain in which religious norms have until recently been able to resist emancipatory gains: sexual freedoms. We present (1) crossnational, (2) longitudinal, (3) generational and (4) multilevel evidence on an unprecedentedly broad basis in support of this theory.

The allure of the waterpipe: a narrative review of factors affecting the epidemic rise in waterpipe smoking among young persons globally

Objective

The objective of this narrative review is to highlight the determinants of the epidemic rise in waterpipe tobacco smoking (WTS) among youth globally. The Ecological Model of Health Promotion (EMHP) was the guiding framework for the review.

Data sources

The following electronic databases were searched: Cochrane library, MEDLINE, EMBASE, PsycINFO, Web of Science and CINAHL Plus with Full Text. Search terms included waterpipe and its many variant terms.

Study selection

Articles were included if they were published between 1990 and 2014, were in English, were available in full text and included the age group 10–29 years.

Data extraction

Articles which analysed determinants of WTS at any of the levels of the EMHP were retained regardless of methodological rigour: 131 articles are included. Articles were coded in a standard template that abstracted methods as well as results.

Data synthesis

The review found that methodologies used to assess determinants of WTS among youth were often conventional and lacked rigor: 3/4 of the studies were cross-sectional surveys and most enrolled non-representative samples. Within the framework, the review identified determinants of WTS at the intrapersonal, interpersonal, organisational, community and policy levels.

Conclusions

The review suggests potential interventions to control WTS among youth, with emphasis on creative utilisation of social media, and tobacco control policies that include the specificities of WTS. The review further suggests the need for rigorous qualitative work to better contextualise determinants, and prospective observational and experimental studies that track and manipulate them to assess their viability as intervention targets.

Structural and functional responses of benthic invertebrates to imidacloprid in outdoor stream mesocosms

Structural and functional responses of a benthic macroinvertebrate assemblage to pulses of the insecticide imidacloprid were assessed in outdoor stream mesocosms. Imidacloprid pulses reduced invertebrate abundance and community diversity in imidacloprid-dosed streams compared to control streams. These results correlated well with effects of imidacloprid on leaf litter decomposition and feeding rates of Pteronarcys comstocki, a stonefly, in artificial streams. Reductions in oxygen consumption of stoneflies exposed to imidacloprid were also observed in laboratory experiments. Our findings suggest that leaf litter degradation and single species responses can be sensitive ecotoxicological endpoints that can be used as early warning indicators and biomonitoring tools for pesticide contamination. The data generated illustrates the value of mesocosm experiments in environmental assessment and how the consideration of functional and structural endpoints of natural communities together with in situ single species bioassays can improve the evaluation and prediction of pesticide effects on stream ecosystems.

Disposition of foscarnet during peritoneal dialysis

OBJECTIVE

To report the disposition of foscarnet in a patient undergoing peritoneal dialysis.

CASE SUMMARY

A 34-year-old man with AIDS received foscarnet for the treatment of esophageal cytomegalovirus. We characterized the clearance of foscarnet in this patient during continuous cyclic peritoneal dialysis (CCPD) and continuous ambulatory peritoneal dialysis (CAPD).

DISCUSSION

The foscarnet half-lives during CCPD and CAPD were 41.4 and 45.8 hours, respectively. These values are significantly greater than the half-life of 4.5 hours observed in patients with normal renal function and about half that reported in anuric patients undergoing hemodialysis during the interdialytic period. The CCPD and CAPD clearances of foscarnet were 5.8 and 4.5 mL/min, respectively; the CAPD clearances of creatinine and urea nitrogen were 4.1 and 6.0 mL/min, respectively. The patient's estimated total body clearance values of foscarnet during CCPD and CAPD were 9.8 and 8.8 mL/min, respectively. Thus, CCPD and CAPD augmented the patient's residual clearance of foscarnet by 145% and 105%, respectively.

CONCLUSIONS

Since incremental increases in residual clearance of 30% or more generally will result in clinically significant changes in a drug's serum concentration, foscarnet dosage needs to be individualized for patients receiving peritoneal dialysis.

The effect of renal insufficiency and hemodialysis on the pharmacokinetics of nalmefene

The disposition of nalmefene, an opioid antagonist intended for the reversal of opioid-induced respiratory depression, and its primary metabolite nalmefene glucuronide, were characterized in adult volunteers with normal renal function and in patients with end-stage renal disease (ESRD). The effect of hemodialysis on the elimination of nalmefene and nalmefene glucuronide also was assessed. Participants with normal renal function received a single intravenous dose of 2 mg, and patients with ESRD received two separate doses of 1 mg nalmefene hydrochloride. Terminal elimination half-life (t1/2) of both nalmefene and nalmefene glucuronide was prolonged in patients with ESRD compared with that in participants with normal renal function. The steady-state volume of distribution (Vdss) of nalmefene was significantly higher and total body clearance lower in patients with ESRD than in participants with normal renal function. Hemodialysis clearance of nalmefene was approximately 3.3% of total body clearance. Although the hemodialysis clearance of nalmefene glucuronide was 179.3 +/- 24.1 mL/min and its t1/2 was significantly reduced during dialysis to 5.2 +/- 2.3 hours, a dramatic rebound of nalmefene glucuronide concentrations of 75.7% was observed 7.7 +/- 5.4 hours after the end of hemodialysis. Thus, hemodialysis does not result in clinically significant alterations in the disposition of nalmefene or its primary metabolite, nalmefene glucuronide. These data suggest that there is no pharmacokinetic basis for modification of the initial dosage, but maintenance doses, if needed, should be administered less frequently due to the prolonged elimination of the active moiety, nalmefene.

Medication knowledge and compliance among patients receiving long-term dialysis

The extent to which patients receiving longterm dialysis understood and complied with their drug therapy regimens was studied. Patients undergoing long-term hemodialysis or continuous ambulatory peritoneal dialysis (CAPD) in a university-affiliated outpatient dialysis center were surveyed to determine their knowledge about and compliance with prescribed regimens for antihypertensives, phosphate binders, and calcitriol. They were asked to list their prescribed medications and state the medications' indications, the frequency with which they missed doses, and the actions they took after missing a dose. The patients were also asked where they obtained their medications and who their primary source of drug information was. Seventy-two patients (51 receiving hemodialysis and 21 receiving CAPD) were surveyed. Although 80% of the patients could recall the three target medications, only 39% of the hemodialysis patients and 57% of CAPD patients could recall all of their medications. Significantly more patients knew the indication for their antihypertensive medication and calcitriol than for their phosphate binder. The hemodialysis and CAPD patients reported they missed an average of 13.0 and 4.7 phosphate binder doses, 2.6 and 5.6 antihypertensive doses, and 6.7 and 7.0 calcitriol doses, respectively, per month. Despite the fact that 70% of the patients received their medications from a community pharmacy, less than 15% identified the pharmacist as their primary source of drug information. Patients receiving long-term hemodialysis or CAPD were more knowledgeable about and compliant with their antihypertensive and calcitriol regimens than their phosphate binder regimens.

Accumulation and pepsin solubility of collagens in the bowel of patients with Crohn's disease

The collagen content of resected strictured intestine, with and without fistulas, from patients with Crohn's disease has been compared with that in macroscopically normal intestine removed from the same patients and from others without inflammatory bowel disease. Collagen content per unit wet or dry weight of tissue was significantly increased in all grossly diseased tissue whether fistulated or not. Although there was a significant increase in collagen types I, III, and V in diseased tissue, the relative proportions of major collagen types extracted by limited pepsin digestion were similar for both Crohn's and non-Crohn's intestine (type I, 65 to 70 percent; type III, 25 to 30 percent; type IV, 2 to 3 percent; and type V, 2.5 to 3 percent). CNBr digestion of pepsin insoluble material showed a similar relative abundance of types I and III, indicating no major change in collagen type distribution between older (insoluble) and more newly synthesized collagen. There was no evidence of the presence of type I trimer collagen. Type VI collagen, although not quantitated, was observed in 70 percent of intestinal specimens. The proportion of total collagen solubilized by pepsin treatment was significantly greater in both grossly diseased and macroscopically normal Crohn's bowel compared with non-inflammatory bowel disease bowel. These findings suggest that there are disturbances of collagen metabolism in Crohn's intestine, which account for the stricturing process and which may predate gross pathologic changes.