Environmental Economics and Policy： Two Way Learning between China and the Rest of the World

Environmental degradation poses perhaps the greatest challenge to present day China as it continues to improve the living standard and general welfare of its citizens. According to a recent Pew Research Center survey （Pew Research Center, 2013）, air pollution and water pollution are among the top five public concems in China, coming after inflation, inequality and corruption. Water pollution is also among the top five issues for which the public concern has increased the most during the past five years, coming after food safety, medicine and manufactured goods, and old age insurance. Yet, despite public concerns and increased abatement expenditures, major pollution levels have been increasing rather than decreasing. For many days during 2013, large parts of eastern China have suffered from blanketing thick smog caused by PM2.5 pollution, with airports and freeways shut down and schools closed.

Biochar amendment changed soil-bound fractions of silver nanoparticles and ions but not their uptake by radish at an environmentally-relevant concentration

Plant uptake of silver nanoparticles(Ag NPs)and ions(Ag^(+))largely depends on their exchangeable and soil-bound fractions in soils,which may be influenced by biochar amendment.This study investigated the effects of biochar amendment(0.1%and 1.0%)on soil sorption of Ag NPs and Ag^(+),their soil-bound fractions,and their uptake and translocation by radish grown in a loamy sand soil spiked with 1 mg/kg Ag NPs or Ag^(+).Sorption of Ag^(+)to the soils was much greater than that of Ag NPs,mainly because negatively charged soil particles would attract Ag^(+),but repel negatively charged Ag NPs.Biochar amend-ment at 1.0%(by weight)significantly decreased the reducible fraction of Ag^(+)in the soils with and without radish plants and increased the oxidisable fraction of Ag NPs in the soils with radish plants.Biochar amendment had no significant effect on Ag uptake by radish plants(p>0.05),probably due to low exchangeable Ag fractions in all experimental treatments.In this short-term experiment(35 days),the addition of 1 mg/kg Ag NPs or Ag^(+)did not substantially elevate the level of Ag in radish roots(0.05±0.02-1.06±0.98 mg/kg)and shoots(0.01±0.00-0.03±0.01 mg/kg),compared to the blank control(p>0.05).Radish uptake of Ag NPs and Ag^(+)at the environmentally-relevant concentration was low with root concentration factors between 0.03±0.03 to 0.29±0.21 and root-to-shoot translocation factors between 0.08±0.10 to 0.89±1.21,which may partially explain the non-significant effect of biochar amendment on Ag uptake.

An integrated approach to understanding the linkages between ecosystem services and human well-being

In order to use science to manage human-nature interactions,we need much more nuanced,and when possible,quantitative,analyses of the interplay among ecosystem services(ES),human well-being(HWB),and drivers of both ecosystem structure and function,as well as HWB.Despite a growing interest and extensive efforts in ES research in the past decade,systematic and quantitative work on the linkages between ES and HWB is rare in existing literature,largely due to the lack of use of quantitative indicators and integrated models.Here,we integrated indicators of human dependence on ES,of HWB,and of direct and indirect drivers of both using data from household surveys carried out atWolong Nature Reserve,China.We examined how human dependence on ES and HWB might be affected by direct drivers,such as a natural disaster,and how human dependence on ES and direct and indirect drivers might affect HWB.Our results show that the direct driver(i.e.,Wenchuan Earthquake)significantly affected both households’dependence on ES and their well-being.Such impacts differed across various dimensions of ES and well-being as indicated by subindices.Those disadvantaged households with lower access to multiple forms of capital,more property damages,or larger revenue reductions also experienced greater losses in HWB.Diversifying human dependence on ES helps to mitigate disaster impacts on HWB.Our findings offer strong empirical evidence that the construction of quantitative indicators for ES and HWB,especially integrated models using them,is a viable approach for advancing the understanding of linkages between ES and HWB.

The Value of Clean Air in China： Evidence from Beijing and Shanghai

We estimate the willingness to pay （WTP） of Beijing and Shanghai residents for improving the air quality of the two cities from their levels prior to the 2008 Beijing Olympic Games to the level achieved during the Olympics. The data are obtained from a contingent valuation study conducted through face-to-face interviews in June 2008 in Beijing and Shanghai prior to the Beijing Olympics, during which time there was intensive debate about Beijing＇s air quality. Residents in both cities are willing to pay more when they are more exposed to air pollution, when their disposable income increases, and when they have stronger beliefs that public opinion plays an important role in government policy making. Beijing residents are willing to pay more than Shanghai residents, due possibly to Beijing＇s poorer air quality. Overall, aggregate WTP for air quality improvement accounts for about 0.53% of the 2008 GDP in Beijing and 0.22% of the 2008 GDP in Shanghai.

Exposure to trace levels of metals and fluoroquinolones increases inflammation and tumorigenesis risk of zebrafish embryos

Exposure to trace-level heavy metals and antibiotics may elicit metabolic disorder,alter protein expression,and then induce pathological changes in zebrafish embryos,despite negligible physiological and developmental toxicity.This study investigated the single and combined developmental toxicity of fluoroquinolones(enrofloxacin[ENR]and ciprofloxacin[CIP])(
0.5 mM)and heavy metals(Cu and Cd)(
0.5 mM)to zebrafish embryos,and molecular responses of zebrafish larvae upon exposure to the single pollutant(0.2 mM)or a binary metal-fluoroquinolone mixture(0.2 mM).In all single and mixture exposure groups,no developmental toxicity was observed,but oxidative stress,inflammation,and lipid depletion were found in zebrafish embryos,which was more severe in the mixture exposure groups than in the single exposure groups,probably due to increased metal bioaccumulation in the presence of ENR or CIP.Metabolomics analysis revealed the up-regulation of amino acids and down-regulation of fatty acids,corresponding to an active response to oxidative stress and the occurrence of inflammation.The up-regulation of antioxidase and immune proteins revealed by proteomics analysis further confirmed the occurrence of oxidative stress and inflammation.Furthermore,the KEGG pathway enrichment analysis showed a significant disturbance of pathways related to immunity and tumor,indicating the potential risk of tumorigenesis in zebrafish larvae.The findings provide molecular-level insights into the adverse effects of heavy metals and antibiotics(especially in chemical mixtures)on zebrafish embryos,and highlight the potential ecotoxicological risks of trace-level heavy metals and antibiotics in the environment.

Depth Distributions of Belowground Production, Biomass and Decomposition in Restored Tallgrass Prairie

Grasslands store large stocks of soil organic carbon(SOC) in the subsoil, but our knowledge of belowground processes becomes less robust with depth. Vertically explicit SOC models typically assume that the depth distribution of belowground production follows the depth distribution of belowground biomass, but this assumption has not been tested. In addition to the effects of soil temperature and moisture on decomposition, some vertically explicit SOC models implement an intrinsic decrease in belowground decomposition with depth, yet this effect has rarely been observed empirically. We simultaneously measured the depth distributions of belowground biomass, production, and litter decomposition to assess whether belowground biomass depth distributions were suitable predictors of belowground production and whether belowground decomposition decreased with soil profile depth. We found that live and total(live +dead) belowground biomass was distributed relatively more shallowly than total belowground production, and thus total belowground biomass was a biased predictor of the vertical distribution of belowground production. The depth distribution of live roots < 2 mm in diameter was found to be the best predictor of total belowground production depth distribution. Using an intact decay core method,we found that belowground litter decomposition decreased by 49% from 0–10 to 30–40 cm depth, and model-simulated effects of soil temperature and moisture accounted for only 9% of the observed decrease with depth. Vertically explicit SOC models can be improved with more accurate empirical belowground production depth distribution estimates, but depth-specific decomposition rates currently implemented in SOC models are necessary to explain observed decreases in belowground litter decay with depth.