Arsenic uptake and transport of Pteris vittata L.as influenced by phosphate and inorganic arsenic species under sand culture

In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in As-hyperaccumulator,uptake and transport of arsenate(As(V))and arsenite(As(III))were studied using Pteris vittata L.under sandculture.Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P.vittata.The reduction in As accumulation was greater in old fronds than in young fronds,and relatively weak in root and rhizome.Moderateincreases,from 0.05 to 0.3 mmol/L,in phosphate reduced uptake of As(III)more than As(V),while the reverse was observed at highconcentrations of phosphate(1.0 mmol/L).Phosphate apparently reduced As transport and the proportion of As accumulated in frondsof P.vittata when As was supplied as As(V).It may in part be due to competition between phosphorus and As(V)during transport.Incontrast,phosphate had a much smaller effect on As transport when the As was supplied as As(III).Therefore,the results from presentexperiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P.vittata,especially inthe fronds,when exposed to As(V);but the suppression of phosphate to As transport may be insignificant when P.vittata exposed toAs(III)under sand culture conditions.The finding will help to understand the interaction of P and As during their uptake process in P.vittata.     

Uptake of copper ion by activated sludge and its bacterial community variation analyzed by 16S rDNA

The effect and uptake of copper ion on SBR(sequence batch reactor)biological treatment system was studied.special nutrient and powder activated carbon(PAC)additive were tested as uptake stimulation technique.Results showed that copper ion had higher effect on unacclimated activated sludge system than on acelimated one.The special nutrient adding could enhance the uptake of copper significantly,while PAC adding could improve the sludge settling and decrease the turbidity of effluent.The variation of bacterial community analyzed by 16S rDNA method showed the acclimation of copper could increase copper resistance species,and excess accumulation could cause some species diminish.It was confirmed that acclimation could improve the resistance and uptake ability of microorganism to heavy metal.     

A novel multistage anoxic/aerobic process with sludge regeneration zone (R-MAO) for advanced nitrogen removal from domestic sewage

To achieve advanced nitrogen removal from actual municipal sewage, a novel multistage anoxic/aerobic process with sludge regeneration zone (R-MAO) was developed. The reactor was used to treat actual domestic sewage and the nitrogen removal capacity of the sludge regeneration zone (R zone) was investigated during the long-term operation. The best performance was obtained at the R zone's Oxidation-Reduction Potential (ORP) of -50±30 mV and hydraulic residence times (HRT) of 1.2 hr. The average effluent COD, TN, NH₄⁺-N and NO₃⁻-N of the R-MAO process were 18.0±2.3, 7.5±0.6, 1.0±0.5 and 4.6±0.4 mg/L, respectively, with the corresponding removal efficiency of COD, TN and NH₄⁺-N were 92.9%±1.0%, 84.1%±1.5% and 97.5%±1.1%. Compared to the sole MAO system, the TN removal efficiency of the R-MAO increased by 10.1%. Besides, under the optimal conditions, the contribution of the R zone in the R-MAO that removal COD, TN, NH₄⁺-N and NO₃⁻-N were 0.36, 0.15, 0.032 and 0.82 g/day. High-throughput sequencing results showed that uncultured_bacterium_f_Burkholderiaceae (5.20%), OLB8 (1.04%) and Ottowia (1.03%) played an important role in denitrification in the R zone. This study provided effective guidance for the design and operation of the R-MAO process in domestic sewage treatment.     

东北三江平原土壤氧化CH4研究

三江平原土壤不同深度氧化大气浓度CH4和高浓度CH4的速率具有明显的垂直差异 .2个非淹水土壤整个剖面都具有氧化大气浓度CH4的潜力 ,以表层土的速率为最大 .非淹水的耕作土壤残留的有机质层仍保留了较强的氧化大气浓度CH4潜力 ,氧化CH4速率是耕作层的 2 0倍 .淹水土壤的大部分层次不具有氧化大气浓度CH4的潜力 .所有供试土壤均能消耗高浓度CH4,泥炭含量较高的土壤层次比矿质层氧化高浓度CH4的速率高     

金鱼(Carassius auratus L.)对水中游离态铅的吸收积累及鳃分泌粘液的自身保护作用

研究了金鱼（ Ｃａｒａｓｓｉｕｓａｕｒａｔｕｓ Ｌ．） 在铅暴露实验中的铅吸收过程及鱼鳃分泌物的自身保护作用、水相Ｐｂ２＋ 的鳃吸收机理以及分泌粘液对铅的络合作用．结果表明，金鱼因铅暴露导致粘液分泌量增加．结合到鳃上的铅与水相Ｐｂ２＋ 活度关系可用Ｌａｎｇｍｕｉｒ 吸附等温式表述．据此估算的最大结合量为０－９４２４ ｍ ｍｏｌ／ｋｇ（干重） ．非常接近１ 的Ｈｉｌｌ 常数（１－０１２）说明金鱼鳃上仅有一种类型的Ｐｂ２＋ 结合位点．平均每尾金鱼鳃上Ｐｂ２＋ 的结合位点数达１－６２ ×１０－ ５ ｍ ｍｏｌ，结合的条件稳定常数（ｌｏｇ ＫＰｂ鳃） 为４－８ ．血液铅含量与鳃铅含量间呈显著线性关系．金鱼吸收Ｐｂ２＋ 的主要过程为：Ｐｂ２＋ 结合到鳃上，其后被动扩散或载体转运穿过鳃上皮，进入血液循环．     

Low intensity ultrasound stimulates biological activity of aerobic activated sludge

This work aims to explore a procedure to improve biological wastewater treatment efficiency using low intensity ultrasound. The aerobic activated sludge from a municipal wastewater treatment plant was used as the experimental material. Oxygen uptake rate (OUR) of the activated sludge (AS) was determined to indicate the changes of AS activity stimulated by ultrasound at 35 kHz for 0–40 min with ultrasonic intensities of 0–1.2 W/cm². The highest OUR was observed at the ultrasonic intensity of 0.3 W/cm² and an irradiation period of 10 min; more than 15% increase was achieved immediately after sonication. More significantly, the AS activity stimulated by ultrasound could last 24 h after sonication, and the AS activity achieved its peak value within 8 h after sonication, or nearly 100% higher than the initial level after sonication. Therefore, to improve the wastewater treatment efficiency of bioreactors, ultrasound with an intensity of 0.3 W/cm² could be employed to irradiate a part of the AS in the bioreactor for 10 min every 8 h. Translated from Environmental Science, 2005, 26(4): 124–128 [译自: 环境科学]     

假单胞菌摄磷和释磷条件的研究

考察了碳、硫等物质对废水生物脱磷优势菌假单胞菌磷代谢的影响．结果表明，缺磷环境导致假单胞菌产生过量摄磷现象；假单胞菌无论是经过无碳厌氧、无碳好氧还是无硫厌氧、无硫好氧培养后，转接到富磷培养基内好氧培养时，都产生过量摄磷现象．随着在富磷培养基内的好氧培养时间延长，细菌的摄磷量下降．     

Prenatal diagnosis of zellweger's syndrome by chorionic villus sampling-and a caveat

At 7·5 weeks gestation, two small chorionic villous biopsies were obtained from a woman at risk for Zellweger's cerebro-hepato-renal syndrome, and were separately established in culture. After 3 weeks, dihydroxyacetone phosphate acyltransferase (DHAP-AT) activity was measured in both cultures. The enzyme was markedly deficient in one cell strain and this was subsequently shown to have a male karyotype. However, the second culture had normal enzyme activity and a female karyotype. The pregnancy was terminated at 11·5 weeks gestation, and follow-up studies on fetal tissues confirmed a male fetus with markedly deficient DHAP-AT activity.     

大型磷酸－磷铵企业环境风险的防范

运用工程分析，物料衡算，综合判断等方法对大型磷酸－磷铵企业的重点污染风险因子进行筛选只别，根据磷石膏库暴雨满溢时氟化物对地表水环境的污染影响，含氟废气（事故）排放对大气环境及农作物的污染影响，氨贮罐泄漏及燃爆对大气环境及健康影响的风险评价结果，重点研究了磷酸－磷铵企业环境风险的防范措施。针对广西鹿化肥公司及国内同类厂的一般情况，提出了保证库周排洪导流沟渠通畅，建设备用磷石膏库等防止暴雨满溢污染地染地表水，改造磷酸尾气洗涤吸收系统防止含氟废气（事故）排放，加强氨系统的安全管理以杜绝氨泄漏等防范措施。     

用磷酸铀酰氢（HUP）消除空气中的氚

在常温常压条件下 ,用 4 -7伏的直流电场作用于不同尺寸的磷酸铀酰氢 (HUP)消氚电极 ,在静态和动态情况下 ,考查了它们的消氚特性。对于含 ( 0 51 -1 8 61 )× 1 0 8Bq氚 ,( 30 0 0 -1 2 0 0 0 )× 1 0 - 6 水分的 2 2升空气 ,消氚效率超过 95% ,用液体闪烁计数法 ,测定了消氚后磷酸铀酰氢中氚 ,其中的含量与被试验含氚空气中的氚相一致。