Sustainability of water transfer projects: A systematic review.

Inter-basin water transfer projects (IBTs) have significantly increased in number in recent decades due to the unremitting need to solve the problem of global water imbalance. However, given the complex challenges inherent in implementing and maintaining IBTs, there is a need to characterize the multi-faceted aspects of sustainability (or unsustainability) that result from these megaprojects. Through a systematic review of the literature, we sought to identify and characterize the positive and negative impacts that most often influence the sustainability of IBTs, focusing on impacts within the environmental, social, and economic pillars of sustainability. Based on an eligibility criterion, the systematic review selected 68 documents out of an initial total of 1567 for information quality analysis and content evaluation. The qualitative coding of the documents allowed us to characterize the landscape of impacts that result from IBTs across the three pillars of sustainability. The study findings revealed that the most frequently coded positive impacts related to the environmental pillar of sustainability, while the most frequently coded negative impacts related to both social and environmental pillars. In addition, the most frequently coded positive impact overall related to the economic benefits generated by the IBTs. Through a critical analysis of the study findings, we provide an assessment of future IBTs with a focus on the UN sustainable development goals.

Is waist-to-height ratio a better predictor of hypertension and type 2 diabetes than body mass index and waist circumference in the Chilean population?

OBJECTIVE: The aim of this study was to identify which anthropometric measurement (body mass index [BMI], waist circumference [WC], or waist-to-height ratio [WHtR]) is a better predictor of type 2 diabetes and hypertension in the Chilean population. METHODS: The study included 13 044 participants (59.7% women) from the Chilean National Health Surveys conducted in 2003, 2009-2010, and 2016-2017. BMI, WC, and WHtR were the anthropometric measurements evaluated. Hypertension was defined as systolic blood pressure ≥140 mm Hg and diastolic blood pressure ≥90 mm Hg or on medication for hypertension. Diabetes was defined as fasting glucose ≥7 mmol/L or on medication for diabetes. The receiver operating characteristics (ROC) curve and the area under curve (AUC) were computed to derive the specificity and sensitivity using a bootstrapping approach. RESULTS: Compared with BMI and WC, WHtR was the anthropometric measurement with the highest AUC curve in both sexes for hypertension (AUC for women: 0.70; 95% confidence interval [CI], 0.67-0.73; AUC for men: 0.71; 95% CI, 0.69-0.74) and diabetes (AUC for women: 0.71; 95% CI, 0.66-0.77; AUC for men: 0.71; 95% CI, 0.67-0.76). The sex-specific cutoff points of WHtR to predict hypertension were 0.59 and 0.55 for women and men, respectively. Those used to predict diabetes were 0.60 and 0.58 for women and men, respectively. CONCLUSION: WHtR was a better predictor of hypertension and diabetes than BMI and WC in Chile. The definition of cutoff points specific for the Chilean population could be implemented in future screening programs aiming to identify high-risk individuals.

Optimal cut-off points for waist circumference in the definition of metabolic syndrome in Chile.

OBJECTIVE: To identify sex-specific cut-off points for waist circumference (WC) in the definition of metabolic syndrome (MetS) for the Chilean adult population. DESIGN: MetS was defined as the presence of at least two out of four of the following criteria: TAG ≥1·7 mmol/l; HDL-cholesterol: <1·3 mmol/l in women and <1·0 mmol/l in men; systolic blood pressure ≥130 mmHg and/or diastolic blood pressure ≥85 mmHg; and fasting glucose ≥ 5·6 mmol/l or current treatment for diabetes. The receiver operating characteristics curve and the AUC were computed to derive the specificity and sensitivity using bootstrapping (10 000 iterations restricted to have at least between 40 and 60 % of the original population). The optimal cut-off point for the Chilean population was computed by sex. SETTING: A representative sample of the Chilean population aged ≥15 years. PARTICIPANTS: 8182 participants (60 % women) from the three available Chilean National Health Surveys conducted in 2003, 2009-2010 and 2016-2017. RESULTS: WC had a good predictive ability for MetS (AUC for men 0·74 (95 % CI 0·72, 0·76); AUC for women 0·71 (95 % CI 0·68, 0·73)). The optimal cut-off points for WC, in the definition of MetS, were 92·3 cm (95 % CI 90·5, 94·4) and 87·6 cm (95 % CI 85·8, 92·1) for men and women, respectively. CONCLUSIONS: The mentioned cut-off points should be used for WC in the definition of MetS in Chile. As a result, the current recommendation (WHO/International Diabetes Federation) for WC, in the identification of MetS, is not supported by these findings in a representative sample of the Chilean adult population.

The economic value of imports of combustible waste in systems with high shares of district heating and variable renewable energy.

This study analyses the socio-economic value of trade of combustible waste, taking Denmark as an example for importing countries with large district heating networks and already high shares of variable renewable energy. An integrated systems analysis framework allowed to assess under which circumstances import of wastes leads to less expensive waste management and energy, accounting for increasing ambitions for a circular economy and renewable energy. The dynamics of both systems are captured through two optimization models, which are solved simultaneously. OptiFlow optimizes Danish waste management and transport, and Balmorel, the Northern European energy system. Results show that waste import to cover the existing Danish incineration overcapacity during wintertime has definite economic value. Conversely, summertime import can have negative value unless a gate fee is received, with the exception of imports of waste with high calorific content (>16.2 GJ/t). In some cases, mothballing of up to 14% of the existing incineration plants is a cost-efficient alternative to decrease the level of over-capacity. In the longer term, results show a socio-economic value of importing waste, being mainly sensitive to assumptions regarding biomass prices and wind power cost, as the technologies would compete with incineration plants. The present methodology can be applied to other countries where waste-to-energy participates in district heating, and where variable renewable electricity and constraints on biomass resources are becoming important. A pan-regional approach regarding waste management planning to maximize the value from combustible waste might be desired, along with a coherent taxation to avoid competition based on tax differences.

The climate footprint of imports of combustible waste in systems with high shares of district heating and variable renewable energy.

This work addressed the role of waste-to-energy (WtE) within the growing paradigm of the circular economy (CE), by combining long-term co-optimization of waste management and energy systems, to determine possible economic and climate impact consequences of future WtE capacity utilization. Co-optimization was realized by integration of a network optimization model for the waste sector, OptiFlow, with the partial equilibrium energy systems model Balmorel. The modelling framework allows to determine the effects of waste-derived energy production within energy systems, including induced and avoided energy (production and long-term investments). The article documents the application of this framework to an analysis of waste trade for WtE between European countries in the base year 2014 and prospectively until 2035, taking Denmark as example for an importing country. Results indicating present and long-term economic benefits for waste trade, under socio-economic conditions, were documented in a concurrent publication. Here, a broader consequential LCA approach was employed to appraise climate change impact potential in a variety of foreground and background conditions. We find that in 2014, trade of residual combustible waste was mostly beneficial from a climate perspective, as the Danish energy system still relies partly on fossil fuels. Towards 2035, climate advantages are uncertain and dependent on avoidance of higher impact waste management (i.e. sanitary landfilling), the differences in the energy carbon-intensity of importing and exporting countries, impact of global biomass supply, and the type and quantity of traded waste. In general, benefits from waste-derived energy production will be offset by direct combustion emissions as background systems decarbonize. Waste transport played only a minor role in the outcome. The study showcases integration of ESA in waste LCA to better account for affected (often referred as marginal) energy production.