Journal of Environmental Sciences Index （ No. 1 - No. 6）

OrganiccarbonstockintopsoilofJiangsuProvince,China,andtherecenttrendofcarbonsequestrationPANGen xing,LILian qing,ZHANGQi,WANGXu kui,SUNXing bin,XUXiao boandJIANGDing an(1)………………………………………………InvestigationofnaturalVOCemittedfromtropicalvegetationsinChinaWANGZhi hui,BAIYu hua,LIUZhao rong,WANGXue song,LIQing junandL.F.Klinger(8)……………………………………………………………PhytoremediationforphenanthreneandpyrenecontaminatedsoilsGAOYan zhengandZHULi zh…     

Journal of Environmental Sciences Index （No. 1- No. 12）

Review Development of analytical methods for Polyeyclie aromatic hydrocarbons(PAHs)in air伙〕rne Particulates:A review LIULi一hin，LIUY自11，LIN Jin一而ng，TANG Ning，HAYAKAW人Kazulchi and MAEDA Tsuneaki··························     

Stability of soil organic carbon changes in successive rotations of Chinese fir （Cunninghamia lanceolata （Lamb.） Hook） plantations

The importance of soil organic carbon (SOC) under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass. We investigated the e ects of successive rotations of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations on the stability of SOC and its availability to microbes by adopting the two-step hydrolysis with H2SO4 and density fractionation. The results showed that successive rotations of Chinese fir decreased the quantity of total SOC, recalcitrant fraction, and carbohydrates in Labile Pool I (LP I), and microbial properties evidently, especially at 0–10 cm horizon. However, cellulose included in Labile Pool II (LP II) and the cellulose/total carbohydrates ratio increased in successive rotations of Chinese fir. The noncellulose of carbohydrates included in LP I maybe highly available to soil microbial biomass. Hence the availability of SOC to microbial biomass declined over the successive rotations. Although there was no significant change in recalcitrance of SOC over the successive rotations of Chinese fir, the percentage of heavy fraction to total SOC increased, suggesting that the degree of physical protection for SOC increased and SOC became more stable over the successive rotations. The degradation of SOC quality in successive rotation soils may be attributed to worse environmental conditions resulted from disturbance that related to “slash and burn” site preparation. Being highly correlated with soil microbial properties, the cellulose/total carbohydrates ratio as an e ective indicator of changes in availability of SOC to microbial biomass brought by management practices in forest soils.     

Arsenic uptake, accumulation and phytofiltration by duckweed （Spirodela polyrhiza L.）

This study investigates arsenic (As) accumulation and tolerance of duckweed Spirodela polyrhiza L: and its potential for As phytofiltration. S. polyrhiza was able to survive in high concentration of As(V) solution: The EC50 values ( SE) based on the external As(V) were (181.66 20.12) mol/L. It accumulated (999 95) mg As/kg dw when exposed in 320 mol/L As(V) solution for one week, and was able to take up appropriately 400 mg As/kg dw in tissues without a significant biomass loss. The EC50 values (the e ective concentration of As(V) in the nutrient solution that caused a 50% inhibition on biomass production) was (866 68) mg/kg dw for the tissues, indicating that S. polyrhiza had a high capability of As accumulation and tolerance. The uptake kinetic parameters Vmax was (55.33 2.24) nmol/(g dw min) and Km was (0.144 0.011) mmol/L. Within 72 hr, S. polyrhiza decreased As concentration in the solution from 190 to 113 ng/mL with a removal rate of 41%. The study suggested that this floating aquatic plant has some potential for As phytofiltration in contaminated water bodies or paddy soils.     

Introduction to the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences （http：//www.rcees.ac.cn）

Research Center for Eco-Environmental Sciences （RCEES）, Chinese Academy of Sciences （CAS）, formerly Institute of Environmental Chemistry, Chinese Academy of Sciences, was founded in 1975. In 1986, it was amalgamated with Research Center of Ecology, CAS, and was renamed as Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Since 1996, RCEES was under the jurisdiction of both Chinese Academy of Sciences and State Environmental Protection Administration.