Adaptive Water Resource Planning in the South Saskatchewan River Basin: Use of Scenarios of Hydroclimatic Variability and Extremes

The South Saskatchewan River Basin is one of Canada's most threatened watersheds, with water supplies in most subbasins over‐allocated. In 2013, stakeholders representing irrigation districts, the environment, and municipalities collaborated with researchers and consultants to explore opportunities to improve the resiliency of the management of the Oldman and South Saskatchewan River subbasins. Streamflow scenarios for 2025‐2054 were constructed by the novel approach of regressing historical river flows against indices of large‐scale ocean‐atmosphere climate oscillations to derive statistical streamflow models, which were then run using projected climate indices from global climate models. The impacts of some of the most extreme scenarios were simulated using the hydrologic mass‐balance model Operational Analysis and Simulation of Integrated Systems (OASIS). Based on stakeholder observations, the project participants proposed and evaluated potential risk management and adaption strategies, e.g., modifying existing infrastructure, building new infrastructure, changing operations to supplement environmental flows, reducing demand, and sharing supply. The OASIS model was applied interactively at live modeling sessions with stakeholders to explore practical adaptation strategies. Our results, which serve as recommendations for policy makers, showed that forecast‐based rationing together with new expanded storage could dramatically reduce water shortages.     

Remobilization of trace elements by forest fire in Patagonia,Chile

Temporal changes in the amounts of trace elements (As, Co, Cu, Mn, Ni, Pb, and Zn) and their correlations with temporal changes in charcoal abundance in age-dated sediments collected from Lake Thompson in Patagonia, Chile, attest to the substantial pyrogenic remobilization of contaminants that occurred in Patagonia during the mid-1900s. This remobilization was concurrent with the extensive slash and burn period in the region during that period. The changes in concentrations of Co, Cu, and Ni in relation to charcoal abundance in the lacustrine sediments over time were small compared to those of As, Mn, Pb, and Zn. However, the relatively low enrichment factors of all those trace elements, normalized to Fe, indicate that they were predominantly derived from local, natural sources impacted by fires rather than industrial sources. The primarily local source of Pb in the sediments was corroborated by the temporal consistency of its isotopic ratios (²⁰⁶Pb/²⁰⁷Pb:²⁰⁸Pb/²⁰⁶Pb), which were similar to previously reported values for natural lead in Central and Southern Chile. However, the pyrogenic remobilization of both natural and industrial trace elements by forest fires in Chile and elsewhere is expected to rise as a consequence of climate change, which is projected to increase both the frequency and intensity of forest fires on a global scale.     

Biodegradability and Mechanical Properties of Poly(vinyl alcohol)-Based Blend Plastics Prepared Through Extrusion Method

Plastic blend materials consisting of poly(vinyl alcohol), glycerol and xanthan or gellan were prepared through laboratory extrusion. Their base mechanical properties were compared with the properties of poly(vinyl alcohol) foil and their biodegradability in soil, compost and both activated and anaerobic sludge were assessed. In samples with lower polysaccharide content (10–21 %w/w) the tensile strength of 15–20 MPa was found; the elongation at break of all blends was relatively close to the parameter of poly(vinyl alcohol) foil. The biodegradability levels of the blends tested corresponded to the content of natural components, and the mineralization of the samples with the highest carbohydrate proportion (42 %) reached 50–78 %, depending on the type of the environment. Complete biodegradation of all samples occurred in activated sludge.     

Variation patterns in individual fish responses to chemical stress among estuaries, seasons and genders: the case of the European flounder (Platichthys flesus) in the Bay of Biscay

The objective was to describe and model variation patterns in individual fish responses to contaminants among estuaries, season and gender. Two hundred twenty-seven adult European flounders were collected in two seasons (winter and summer) in four estuaries along the Bay of Biscay (South West France), focusing on a pristine system (the Ster), vs. three estuaries displaying contrasted levels of contaminants (the Vilaine, Loire and Gironde). Twenty-three variables were measured by fish, considering the load of contaminants (liver metals, liver and muscle persistent organic pollutants, muscle polycyclic aromatic hydrocarbons); the gene expression (Cyt C oxydase, ATPase, BHMT, Cyt P450 1A1, ferritin); the blood genotoxicity (Comet test); and liver histology (foci of cellular alteration–tumour, steatosis, inflammation, abnormal glycogen storage). Canonical redundancy analysis (RDA) was used to model these variables using gender, season and estuary of origin as explanatory variables. The results underlined the homogeneity of fish responses within the pristine site (Ster) and more important seasonal variability within the three contaminated systems. The complete model RDA was significant and explained 35 % of total variance. Estuary and season respectively explained 30 and 5 % of the total independent variation components, whilst gender was not a significant factor. The first axis of the RDA explains nearly 27 % of the total variance and mostly represents a gradient of contamination. The links between the load of contaminants, the expression of several genes and the biomarkers were analysed considering different levels of chemical stress and a possible multi-stress, particularly in the Vilaine estuary.     

Occurrence and levels of organochlorine compounds in human breast milk in Bangladesh

In low-income countries, the use of some organochlorine pesticides is still common in order to increase food production. Monitoring the chemical exposure is an important step in risk-reducing strategies. This is the first study to report concentrations of organochlorines in breast milk of women from Bangladesh where farming is the main income source.Organochlorines such as p,p′-DDT, o,p′-DDT, p,p′-DDE, p,p′-DDD (i.e., ∑DDT), HCB, α-, β- and γ-HCH, trans-chlordane, cis-chlordane, oxy-chlordane, trans-nonachlor, cis-nonachlor, mirex and polychlorinated biphenyls (CB 28, 52, 99, 101, 105, 114, 118, 123, 128, 138, 141, 149, 153, 156, 157, 163, 167, 170, 180, 183, 187, 189, 194) were analyzed in breast milk collected in 2002 from 72 first-time mothers (median age 20 years) living in the rural area Matlab, Bangladesh.While the concentrations of PCBs and many of the pesticides were low, the concentrations of p,p′-DDT and its metabolite p,p′-DDE were high (median 349 and 1645 ng g⁻¹ lipid, respectively) in comparison to other countries. The median value of ∑DDT was 2123 ng g⁻¹ lipid. The estimated daily exposure to p,p′-DDT, p,p′-DDE and ∑DDTs was 10, 30 and 42 μg kg⁻¹ body weight, respectively, in 3 months old infants. The p,p′-DDE/p,p′-DDT ratio ranged from 1 to 23, where 58% of the mothers had a ratio below 5 indicating recent or ongoing DDT exposure.This study reports infant exposure and maternal body burden of organochlorines through breast milk. Although the findings give no reason to limit breast-feeding, it is essential to identify the main exposure sources and find means to decrease the exposure.     

Hexavalent chromium reduction kinetics in rodent stomach contents

Reduction of hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) in the stomach prior to absorption is a well-recognized detoxification process thought to limit the toxicity of ingested Cr(VI). However, administration of high concentrations of Cr(VI) in drinking water cause mouse small intestinal tumors, and quantitative measures of Cr(VI) reduction rate and capacity for rodent stomach contents are needed for interspecies extrapolation using physiologically-based toxicokinetic (PBTK) models. Ex vivo studies using stomach contents of rats and mice were conducted to quantify Cr(VI) reduction rate and capacity for loading rates (1-400 mg Cr(VI) L⁻¹ stomach contents) in the range of recent bioassays. Cr(VI) reduction was measured with speciated isotope dilution mass spectrometry to quantify dynamic Cr(VI) and Cr(III) concentrations in stomach contents at select time points over 1 h. Cr(VI) reduction followed mixed second-order kinetics, dependent upon concentrations of both Cr(VI) and the native reducing agents. Approximately 16 mg Cr(VI)-equivalents of reducing capacity per L of fed stomach contents (containing gastric secretions, saliva, water and food) was found for both species. The second-order rate constants were 0.2 and 0.3 L mg⁻¹ h⁻¹ for mice and rats, respectively. These findings support that, at the doses that caused cancer in the mouse small intestine (?20 mg Cr(VI) L⁻¹ in drinking water), the reducing capacity of stomach contents was likely exceeded. Thus, for extrapolation of target tissue dose in risk assessment, PBTK models are necessary to account for competing kinetic rates including second order capacity-limited reduction of Cr(VI) to Cr(III).     

Unintentional strangulation deaths from the "choking game" among youths aged 6-19 years - United States, 1995-2007

The "choking game" is defined as self-strangulation or strangulation by another person with the hands or a noose to achieve a brief euphoric state caused by cerebral hypoxia. Participants in this activity typically are youths (Andrew & Fallon, 2007). Serious neurologic injury or death can result from engaging in this activity. Recent news media reports have described numerous deaths among youths attributed to the choking game. Because no traditional public health dataset collects data on this practice, CDC used news media reports to estimate the incidence of deaths from the choking game. This report describes the results of that analysis, which identified 82 probable choking-game deaths among youths aged 6-19 years during 1995-2007. Seventy-one (86.6%) of the decedents were male, and the mean age was 13.3 years. Parents, educators, and health-care providers should become familiar with warning signs that youths are playing the choking game (Urkin & Merrick, 2006). Impact of industry: By learning about the risk factors for and warning signs of the choking game, parents, educators, and health-care providers may be able to identify youth at risk for playing the game and prevent future deaths.     

Water quality and restoration in a coastal subdivision stormwater pond

Stormwater ponds are commonly used in residential and commercial areas to control flooding. The accumulation of urban contaminants in stormwater ponds can lead to a number of water quality problems including high nutrient, chemical contaminant, and bacterial levels. This study examined the interaction between land use and coastal pond water quality in a South Carolina residential subdivision pond. Eutrophic levels of chlorophyll and phosphorus were present in all seasons. Harmful cyanobacterial blooms were prevalent during the summer months. Microcystin toxin and fecal coliform bacteria levels were measured that exceeded health and safety standards. Low concentrations of herbicides (atrazine and 2,4-D) were also detected during summer months. Drainage from the stormwater pond may transport contaminants into the adjacent tidal creek and estuary. A survey of residents within the pond's watershed indicated poor pet waste management and frequent use of fertilizers and pesticides as possible contamination sources. Educational and outreach activities were provided to community members to create an awareness of the water quality conditions in the pond. Pond management strategies were then recommended, and selected mitigation actions were implemented. Water quality problems identified in this study have been observed in other coastal stormwater ponds of varying size and salinity, leading this project to serve as a potential model for coastal stormwater pond management.     

Seeing (and doing) conservation through cultural lenses

In this paper, we first discuss various vantage points gained through the authors’ experience of approaching conservation through a “cultural lens.” We then draw out more general concerns that many anthropologists hold with respect to conservation, summarizing and commenting on the work of the Conservation and Community Working Group within the Anthropology and Environment Section of the American Anthropological Association. Here we focus on both critiques and contributions the discipline of anthropology makes with regard to conservation, and show how anthropologists are moving beyond conservation critiques to engage actively with conservation practice and policy. We conclude with reflections on the possibilities for enhancing transdisciplinary dialogue and practice through reflexive questioning, the adoption of disciplinary humility, and the realization that “cross-border” collaboration among conservation scholars and practitioners can strengthen the political will necessary to stem the growing commoditization and ensuing degradation of the earth’s ecosystems.     

Virulence profiles of vancomycin-resistant enterococci isolated from surface and ground water utilized by humans in the North West Province,South Africa: a public health perspective

Environmental Science and Pollution Research - Vancomycin-resistant enterococci (VRE) have been responsible for numerous outbreaks of serious infections in humans worldwide. Enterococcus faecium...