City level water withdrawal and scarcity accounts of China.

In the context of China's freshwater crisis high-resolution data are critical for sustainable water management and economic growth. Yet there is a dearth of data on water withdrawal and scarcity regardless of whether total or subsector amount, for prefectural cities. In administrative and territorial scope, we accounted for water withdrawal of all 63 economic-socio-environmental sectors for all 343 prefectural cities in China, based on a general framework and 2015 data. Spatial and economic-sector resolution is improved compared with previous studies by partitioning general sectors into industrial and agricultural sub-sectors. Construction of these datasets was based on selection of 16 driving forces. We connected a size indicator with corresponding water-withdrawal efficiency. We further accounted for total blue-water withdrawal and quantitative water scarcity status. Then we compared different scopes and methods of official accounts and statistics from various water datasets. These disaggregated and complete data could be used in input-output models for municipal design and governmental planning to help gain in-depth insights into subsector water-saving priorities from local economic activities.

Nasal filter reveal exposure risks of inhalable particulates and heavy metals in urban women.

Urban populations, especially women, are vunerable to exposure to airborne pollution, particularly inhalable particulates (PM10). Thus, more accurate measurement of PM10 levels and evaluating their health effects is critical for guiding policy to improve human health. Previous studies obtained personal PM10 with time-weighted average by air filter-based sampling (AFS), which ignores individual differences and behavioral patterns. Here, we used nasal filters instead of AFS to obtain actual inhaled PM10 under short-term exposure for urban dwelling women during a severe haze event in Beijing in 2016. The levels of six heavy metals such as As, Cd, Ni, Cr, Pb, and Co in PM10 were investigated, and carcinogenic and non-carcinogenic risks evaluated based on an adjusted US EPA health risk assessment model. The health endpoints for urban dwelling women were further assessed through an exposure-reponse model. We found that the hourly inhaled dose of PM10 obtained through the nasal filter was about 2.5-17.6 times that obtained by AFS, which also resulted in 4.41-11.30 times more morbidity than estimated by AFS (p < 0.05). Proximity to traffic emissions resulted in greater exposure to particulate matter (>18.8 µg/kg·h) and heavy metals (>2.2 ng/kg·h), and these populations are therefore at greatest risk of developing non-cancer (HI = 4.16) and cancer (Rt = 7.8 × 10-3) related morbities.

Unveiling the potential for artificial upwelling in algae derived carbon sink and nutrient mitigation.

Mariculture algae may present a crucial part of ocean-based solutions for climate change, with the ability to sequester carbon and remove nutrients. However, the expansion of mariculture algae faces multiple challenges. Here, we measure the changes in algae derived carbon sinks and nitrogen (N) and phosphorus (P) removal between 2010 and 2020 in Shandong Province, China. We further identify the key driving factors, namely area, algal species proportion, and yield, that influence the changes. The results show that algae derived carbon sinks and nutrient removal growth rates in Shandong Province have slowed significantly since 2014, mainly due to area limitations, laver-oriented species change, and unstable yields. Artificial upwelling (AU) has the potential to enhance the yield and subsequently offset the loss of carbon sinks and nutrient removal caused by negative driving factors. Scenario analysis indicates that a complete deployment of AU by 2030 will offset up to a 44.52 % decrease in the mariculture algae area, or a 72.57 % increase in the laver share of the algal species combination compared to 2020. Similar conclusions are reached regarding the role of AU in N and P removal. This study also identifies ancillary challenges such as low energy efficiency and high costs faced by applying AU.

Revealing Trade Potential for Reversing Regional Freshwater Boundary Exceedance.

Applying the planetary boundary for the freshwater framework at the regional level is important in supporting local water management but is subject to substantial uncertainty. Previous estimates have not fully investigated the potential of trade in mitigating regional freshwater boundary (RFB) exceedance. Here, we estimate RFB based on the average results of 15 different hydrological models to reduce uncertainty. We then propose a framework to divide the RFB exceedance/maintenance into contributions from both consumption and trade and further identify trade contribution into six types. We applied the framework to China's provinces, which are characterized by intensive interprovincial trade and a significant mismatch in water resource supply and demand. We found that the current trade pattern limits the role of trade to mitigate RFB exceedance. For the importing provinces exceeding RFBs, 78% of their imported goods and services came from other RFB exceeding provinces. Scenario analysis showed that relying on increased imports alone, even to its greatest extent, will not reverse RFB exceedance in most importing provinces. Increased imports, however, will have an aggregate effect on the trade partners, leading to the exceedance of the national freshwater boundary. We also found that promoting export of goods and services from non-RFB exceeding provinces and reducing their water intensity will help address the imbalance both locally and, in the aggregate, nationally.

Unveiling the dynamic of water-electricity conflict within and beyond megacity boundary.

Electricity demand in megacities may exert substantial stress on water resources, which is often expressed through the water scarcity footprint for electricity consumption (WSFE). Conversely, water scarcity may constrain electricity production, leading to increased vulnerability for megacities electricity production. The WSFE and the water related vulnerability of electricity production reflect two aspects of water-electricity conflict. This varies over time by both the amount and location of electricity production. However, no studies have conducted time-series analysis to evaluate the trends of these two indicators, both in terms of severity and spatial characteristics. Our study focused on evaluating trends in water-electricity conflict both within and beyond megacity administrative boundaries. China's four provincial-level megacities, i.e. Beijing, Tianjin, Shanghai and Chongqing, were chosen as case studies. The results show that water related vulnerability of electricity production in Tianjin, Beijing, Shanghai and Chongqing was diverse and can be classified as extreme, severe, moderate and minor, respectively. Between 2006 and 2016, the WSFE of Tianjin experienced an increasing trend, and its water related vulnerability of electricity production remained at the highest level. Beijing's WSFE has decreased, but its water related vulnerability of electricity production has increased. These differing trends highlight the need for joint reductions to both WSFE and water related vulnerability of electricity production in mitigating water-electricity conflict.

Physical and virtual water transfers for regional water stress alleviation in China.

Water can be redistributed through, in physical terms, water transfer projects and virtually, embodied water for the production of traded products. Here, we explore whether such water redistributions can help mitigate water stress in China. This study, for the first time to our knowledge, both compiles a full inventory for physical water transfers at a provincial level and maps virtual water flows between Chinese provinces in 2007 and 2030. Our results show that, at the national level, physical water flows because of the major water transfer projects amounted to 4.5% of national water supply, whereas virtual water flows accounted for 35% (varies between 11% and 65% at the provincial level) in 2007. Furthermore, our analysis shows that both physical and virtual water flows do not play a major role in mitigating water stress in the water-receiving regions but exacerbate water stress for the water-exporting regions of China. Future water stress in the main water-exporting provinces is likely to increase further based on our analysis of the historical trajectory of the major governing socioeconomic and technical factors and the full implementation of policy initiatives relating to water use and economic development. Improving water use efficiency is key to mitigating water stress, but the efficiency gains will be largely offset by the water demand increase caused by continued economic development. We conclude that much greater attention needs to be paid to water demand management rather than the current focus on supply-oriented management.

Lifting China's water spell.

China is a country with significant but unevenly distributed water resources. The water stressed North stays in contrast to the water abundant and polluted South defining China's current water environment. In this paper we use the latest available data sets and adopt structural decomposition analysis for the years 1992 to 2007 to investigate the driving forces behind the emerging water crisis in China. We employ four water indicators in China, that is, freshwater consumption, discharge of COD (chemical oxygen demand) in effluent water, cumulative COD and dilution water requirements for cumulative pollution, to investigate the driving forces behind the emerging crisis. The paper finds water intensity improvements can effectively offset annual freshwater consumption and COD discharge driven by per capita GDP growth, but that it had failed to eliminate cumulative pollution in water bodies. Between 1992 and 2007, 225 million tones of COD accumulated in Chinese water bodies, which would require 3.2-8.5 trillion m(3) freshwater, depending on the water quality of the recipient water bodies to dilute pollution to a minimum reusable standard. Cumulative water pollution is a key driver to pollution induced water scarcity across China. In addition, urban household consumption, export of goods and services, and infrastructure investment are the main factors contributing to accumulated water pollution since 2000.

Comparison between disintegrated and fermented sewage sludge for production of a carbon source suitable for biological nutrient removal.

There is a need to investigate processes that enable sludge re-use while enhancing sewage treatment efficiency. Mechanically disintegrated thickened surplus activated sludge (SAS) and fermented primary sludge were compared for their capacity to produce a carbon source suitable for BNR by completing nutrient removal predictive tests. Mechanically disintegration of SAS using a deflaker enhanced volatile fatty acids (VFAs) content from 92 to 374 mg l(-1) (4.1-fold increase). In comparison, primary sludge fermentation increased the VFAs content from 3.5 g l(-1) to a final concentration of 8.7 g l(-1) (2.5-fold increase). The carbon source obtained from disintegration and fermentation treatments improved phosphate (PO(4)-P) release and denitrification by up to 0.04 mg NO(3)-Ng(-1)VSS min(-1) and 0.031 mg PO(4)-Pg(-1)VSS min(-1), respectively, in comparison to acetate (0.023 mg NO(3)-Ng(-1)VSS min(-1)and 0.010 mg PO(4)-Pg(-1)VSS min(-1)). Overall, both types of sludge were suitable for BNR but disintegrated SAS displayed lower carbon to nutrient ratios of 8 for SCOD:PO(4)-P and 9 for SCOD:NO(3)-N. On the other hand, SAS increased the concentration of PO(4)-P in the settled sewage by a further 0.97 g PO(4)-P kg(-1)SCOD indicating its potential negative impact towards nutrient recycling in the BNR process.

Remediation of a chlorinated aromatic hydrocarbon in water by photoelectrocatalysis.

Photoelectrocatalysis driven by visible light offers a new and potentially powerful technology for the remediation of water contaminated by organo-xenobiotics. In this study, the performance of a visible light-driven photoelectrocatalytic (PEC) batch reactor, applying a tungsten trioxide (WO(3)) photoelectrode, to degrade the model pollutant 2,4-dichlorophenol (2,4-DCP) was monitored both by toxicological assessment (biosensing) and chemical analysis. The bacterial biosensor used to assess the presence of toxicity of the parent molecule and its breakdown products was a multicopy plasmid lux-marked E. coli HB101 pUCD607. The bacterial biosensor traced the removal of 2,4-DCP, and in some case, its toxicity response suggests the identification of transient toxic intermediates. The loss of the parent molecule, 2,4-DCP determined by HPLC, corresponded to the recorded photocurrents. Photoelectrocatalysis offers considerable potential for the remediation of chlorinated hydrocarbons, and that the biosensor based toxicity results identified likely compatibility of this technology with conventional, biological wastewater treatment.

Alkali Metal Bis(o-anisyl)phosphides: Characterization of MP(C(6)H(4)OMe-o)(2) (M = Li, Na) and Crystal Structure of a Sodium Secondary Organophosphide.

Lithium bis(o-anisyl)phosphide (1)may be prepared by reaction of n-BuLi with bis(o-anisyl)phosphine in THF or toluene; sodium bis(o-anisyl)phosphide (2) is prepared by reaction of sodium with tris(o-anisyl)phosphine in liquid ammonia/THF; both compounds are isolated as unsolvated solids. 1 decomposes quantitatively in THF to give tetrakis(o-anisyl)diphosphine (4); 2 decomposes in THF to give a mixture containing 4 and bis(o-anisyl)phosphine. Addition of diglyme to 2 gives [Na{&mgr;-P(C(6)H(4)OMe-o)(2)}(MeO(CH(2)CH(2)O)(2)Me)](2) (2a), which has been characterized by single-crystal X-ray diffraction. Each Na atom in 2a is 6-coordinate, being bonded to two P atoms, three diglyme O atoms, and one O atom from an o-anisyl group. Crystal data: monoclinic, P2(1)/n, a = 14.549(4) Å, b = 18.555(6) Å, c = 15.846(4) Å, beta = 91.07(2) degrees, Z = 4, final R = 0.041, R(w) = 0.053.