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With a Multi-Regional Input-Output analysis, this study for the first time quantifies China's final electricity demands' life-cycle impacts on water quality using the indicator Grey Water Footprint (GWF). China's Grey Water Footprint for Final Power Demands (GWFP) amounts to 37.54 billion m³ in 2010, which is the highest in the north, east and central regions. Regarding the upstream sectoral contributions on a national scale, Coal Mining and Dressing, whose GWF is decided mainly by Chemical Oxygen Demand (COD) and petroleum, and Agriculture sector, whose GWF is decided by total nitrogen discharged, contribute the largest shares of 32.40% and 23.24%, respectively. 22.28 billion m³ of GWFP is transferred across provincial boundaries as virtual grey water embodied in electricity transmissions and trades of the power sector's upstream supplies. Electric power demands in coastal provinces induce water pollution in inland provinces. For example, 1.38, 1.07 and 1.06 billion m³ of GWF in Shanxi, Inner Mongolia, and Henan, respectively, are generated to fulfill final power demands in Shandong, Jilin and Shandong. Findings in this study are significant in helping policymakers recognize and mitigate final power demands' life-cycle adverse impacts on water quality. Moreover, insights of the inter-provincial virtual grey water transfers induced by power demands enable further discussions on burden sharing and compensation in terms of power demand management and water pollution controls. [ABSTRACT FROM AUTHOR]

Grey water footprint (GWF) accounting has previously been conducted at the global level using a bottom-up approach but lacking detailed industrial information. Here we applied a multi-region input-output approach based on the World Input-Output Database (WIOD) to quantify global GWF of 40 countries/regions with 35 economic sectors. The GWF from both the production perspective (GWFP), and the consumption perspective (GWFC) are quantified. The results show that the global GWFP/GWFC was 1507.9 km3 in 2009. Except for the "Agriculture, Hunting, Forestry and Fishing" sector, the industrial sectors with the largest GWFC were "Food, Beverages and Tobacco", "Construction", "Chemicals and Chemical Products", and "Textiles and Textile Products". The BRIC countries (Brazil, Russia, India, China) had a larger GWFP than their GWFC, which accounted for over half of global GWFP (53.6%), and their GWFP was mainly generated from the production of domestic final demand. In contrast, the OECD29 and EU27 groups of countries i.e. the country groups consisting mainly of economically advanced nations, had larger GWFC than their GWFP. Overall, the OECD29 and EU27 outsourced 134.8 km3 and 64.4 km3 of their grey water respectively, mostly to large newly advanced economies such as the BRIC group of countries, which, in turn, were collectively outsourcing 112 km3 of grey water. Quantitative approaches are thus suggested for development, aimed at shared responsibility for water pollutant discharge among poor exporters and wealthy consumers. • Global Grey Water Footprint (GWF) was quantified from production and consumption perspectives. • Multi-region input-output approach was applied to account for GWF of 40 countries/regions. • Global GWF was 1507.9 km3 in 2009. • BRIC countries accounted for 53.6% of the global GWF from production perspective. • OECD29 and EU27 outsourced 134.8 and 64.4 km3 of their grey water, respectively. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Both water depletion and pollution by coal-fired power generation are quantified. • Petroleum pollutant determines the life cycle grey water footprint. • Water pollution mostly occurs in the fuel supply sector. • The grey water footprint was reduced by 49% from 2002 to 2012. Abstract In the present study, both water depletion and degradation in the life cycle of power generation at coal-fired power plants in China are quantified using a mixed-unit input-output model. National life cycle Withdrawal, Blue and Grey water footprint (WF) of thermal power production in China are estimated to be 35.46, 2.14 and 17.67 m3 per MWh of electricity produced, respectively. Those three types of life cycle WFs experienced significant reductions from 2002 to 2012 due to improved technologies such as water saving and wastewater treatment. Although Chemical Oxygen Demand (COD) pollutant had the largest discharge amount in the life cycle process of electricity generation, petroleum pollutant that was mostly discharged from coal production determined the Grey WF because of its lower permissible concentration. The spatial distribution of scarce WFs, incorporating regional water stresses, is also studied at the provincial level to identify the impacts of thermal power generation on regional water scarcities. Scarce water consumption was concentrated in northern China while scarce water was predominantly withdrawn in eastern China. [ABSTRACT FROM AUTHOR]

Eutrophication is a global challenge, which is exemplified by the tremendous efforts but little results in restoring the sixth largest and also one of the most eutrophic freshwater lakes in China, Lake Dianchi. Considering large parametric uncertainties in water quality modeling, the traditionally used deterministic water quality model is expanded to a probabilistic model to explore the Lake Dianchi's potential responses to different levels of pollutant load reductions. The results show that, given the long pollution history and severe pollution state in Lake Dianchi, a minimum pollution load reduction by half (base year 2003) is required to maintain the water quality state as it is now in 40 years. At least a 60% nutrient load reduction is required to generate any likelihood of water quality improvement, however, the system stabilizes quickly after about 10 years, which may explain why tremendous investments have generated little results. 80% of nutrient load reduction for 40 years has 95% probability of meeting the TN target but only a below 50% (45%) probability in meeting the TP target, and even less to meet water quality target for Chla. The feasibility of ever reaching the Chinese drinking water standards for total phosphorous and total nitrogen is questionable. • An uncertainty-based probabilistic model explores potential policy responses in Lake Dianchi. • 50% pollutant reduction is required to maintain the water quality state as it is now in 40 years. • At least 60% pollutant load reduction is required to achieve water quality improvement. • System stabilizes with 60% pollutant reduction in about 10 years. • 80% pollutant load reduction from land-based sources may still fail to meet target for Chla. [ABSTRACT FROM AUTHOR]