[Objective]The changes of cadmium content,soil available cadmium,phosphorus form and enzyme activity in various parts of rapeseed under phosphorus application conditions were investiga-ted.[Method]A pot-culture experiment was carried out to study the effect of different phosphorus(P)ad-dition on cadmium uptake of rapes,soil phosphorus and cadmium conversion and soil enzyme activity.In the experiment,P concentrations were 5.0,75.0,150.0 mg/kg that was made using KH2PO4,and Cd concentrations were 0.3,3.0,5.0 mg/kg.[Result]The results were as follows:Exogenous phosphorus increased biomass and cadmium accumulation of rape.When the cadmium content in the soil is 3.0 and 5.0 mg,adding 150.0 mg phosphorus to soil,the highest biomass of rapeseed plants is 2.68 and 2.03 g,respectively;the highest accumulation of cadmium was 164.00 and 165.62 μg/pot,respectively.For soil pH,available cadmium content,and phosphorus form content,when the cadmium content in the soil was 3.0 and 5.0 mg,and the phosphorus application amount increased from 5.0 to 150.0 mg,the soil pH decreased by 0.11 and 0.06 units,respectively;the content of soil mineral phosphorus(Ligand-P)de-creased by 10.2％and 10.3％,respectively.The content of soil bioavailable phosphorus(Bioavailable-P)increased by 48.7％and 35.9％,respectively.The soil available cadmium content(DTPA-Cd)decreased by 7.5％and 15.2％,respectively.This indicates that the increase in phosphorus addition reduces soil pH,promotes the release of soil mineral phosphorus,increases the content of soil Bioavailable-P,and re-duces the content of DTPA-Cd.In addition,the enzyme activities of NAG,UE increased with the addition of phosphorus supplemental level,while the activities of ACP,ALP decreased.The results showed that ex-ogenous phosphorus effectively alleviated the demand for phosphorus in the rapes rhizosphere and indirectly promoted the nitrogen cycle.[Conclusion]In conclusion,exogenous phosphorus application can optimize the rhizosphere environment of rapeseed by increasing the content of active phosphorus in soil,reducing the content of available cadmium in soil and promoting the soil nitrogen cycle,thus promoting the growth of rapes and thus increasing the accumulation of cadmium in rapes.

In this paper, a novel adsorbent of magnetic mesoporous carbon microspheres (MCS) are prepared by template methods and using nano-Fe3O4 particles as magnetic cores, and the adsorption capacity and mechanism are studied in detail. The results show that MCS exhibits high performance for removing malachite green (MG), the highest adsorption capacity can reach about 468.5 mg g(-1). Furthermore, the Langmuir adsorption isotherm model and the quasi-second-order kinetic model can explain the experimental phenomena very well. And the high adsorption capacity of MCS is mainly attributed to its unique mesoporous structure by increasing the specific surface area and providing sufficient active sites. In addition, after magnetic separation and recovery, MCS can be regenerated with ethanol. And MCS maintains a high adsorption rate of 84.5 % after 5 cycles of MG adsorption and desorption. This composite material with high adsorption efficiency and rapid magnetic separation is a promising recyclable adsorbent for the actual wastewater treatment and purification process.

The water quality plays an important role for residents living in Xiangjiang valley, Hunan province, southern China. In this study, the contingent valuation method (CVM) was used to estimate the value for improving water quality of Xiangjiang for residents who live in in Chang-Zhu-Tan city cluster including Changsha, Zhuzhou and Xiangtan of Xiangjiang valley. Based on pre-interviewed, 220 questionnaires per city were carried out in Chang-Zhu-Tan city cluster between March and August 2010. Among 660 questionnaires, the 623 questionnaires accounting for 94.3% were effectively. About 99.3% respondents thought that Xiangjiang was becoming worse and it was necessary to improve water quality of Xiangjiang for their health, while 0.7% took it easy. About 70.1% residents wanted to support government to take active measures to improve water quality, while, 29.9% refuse to pay due to sex, age, income, education, and occupation of residents in the interview. According to ranges of willingness to pay (WTP) for residents from CNY 2.0 to 50.0 Yuan (from US$ 0.3 to 7.46), the average WTP was calculated CNY 17.18 Yuan (US$ 2.56) per month per household, and the total economic value was CNY 0.848 billion Yuan (US$ 0.127 billion) for Chang-Zhu-Tan city cluster. Residents were willing to contribute a portion of their incomes to improve the quality of drinking water. Among all factors, there were significant relationships between income and sex and WTP (p<0.05), while the relationships between WTP and the education, age, and occupation of resident’ s are no-significant.