Adsorption and precipitation of tetracycline with struvite.

The interaction of tetracycline with struvite during adsorption and precipitation processes was investigated. Tetracycline removal by adsorption was affected by solution pH, contact time, and struvite concentration. The lowest tetracycline removal (8.4%) was observed at pH 7.7, the dissociation constant (pKa2) of tetracycline. Because of the electrostatic repulsion, the amount of tetracycline adsorbed on the surface was low. The small amount of adsorption was the result of surface complexation between tetracycline ions and metal ions. Calcium (Ca2+) ions in the adsorbent enhanced the binding of tetracycline. Freundlich (KF: 0.04, n: 1.49) and Redlich-Peterson (KR: 0.08, alphaR: 0.98, betaR: 0.49) models best defined the equilibrium data. In the case of struvite precipitation, approximately 22% of tetracycline was removed as a result of binding to struvite alongside struvite formation.     

Air pollution and health: correlation or causality? The case of the relationship between exposure to particles and cardiopulmonary mortality

Many epidemiologic studies have observed, in different contexts, a slight short-term relationship between particles in air and cardiopulmonary mortality, even when air quality standards were respected. The causality of this relationship is important to public health because of the number of people exposed. Our aim was to make a critical assessment of the arguments used in 15 reviews of published studies. We explain the importance of distinguishing validity from causality, and we systematically analyze the various criteria of judgment within the context of ecologic time studies. Our conclusion is that the observed relationship is valid and that most of the causality criteria are respected. It is hoped that the level of exposure of populations to these particles be reduced. In Europe, acting at the root of the problem, in particular on diesel emissions, will also enable the reduction of levels of other pollutants that can have an impact on health. In the United States, the situation is more complicated, as particles are mainly secondary. It is also essential to continue with research to become better acquainted with the determinants of personal global exposures and to better understand the toxic role of the various physicochemical factors of the particles.     

Fixed-bed study for lanthanide (La, Eu, Yb) ions removal from aqueous solutions by immobilized Pseudomonas aeruginosa: experimental data and modelization

A fixed-bed study was carried out by using cells of Pseudomonas aeruginosa immobilized in polyacrylamide gel as a biosorbent for the removal of lanthanide (La, Eu, Yb) ions from aqueous solutions. The effects of superficial liquid velocity based on empty column, particle size, influent concentration and bed depth on the lanthanum breakthrough curves were investigated. Immobilized biomass effectively removed lanthanum from a 6 mM solution with a maximum adsorption capacity of 342 micromolg(-1) (+/-10%) corresponding closely to that observed in earlier batch studies with free bacterial cells. The Bohart and Adams sorption model was employed to determine characteristic parameters useful for process design. Results indicated that the immobilized cells of P. aeruginosa enable removal of lanthanum, europium and ytterbium ions from aqueous effluents with significant and similar maximum adsorption capacities. Experiments with a mixed cation solution showed that the sequence of preferential biosorption was Eu3+ > or = Yb3+ > La3+. Around 96+/-4% of the bound lanthanum was desorbed from the column and concentrated by eluting with a 0.1 M EDTA solution. The feasibility of regenerating and reusing the biomass through three adsorption/desorption cycles was suggested. Neural networks were used to model breakthrough curves performed in the dynamic process. The ability of this statistical tool to predict the breakthrough times was discussed.     

慢性氟暴露致小鼠海马损伤及L-型钙拮抗剂的干预作用

探讨了慢性氟暴露致小鼠海马损伤及L-型钙通道拮抗剂的干预作用.将140只初断乳ICR雄性小鼠随机分为7组：对照组（C组）、高氟组（HF组,饮用30 mg·L^-1 NaF溶液）、低氟组（LF组,饮用5 mg·L^-1 NaF溶液）、高/低氟+L-型钙通道激动剂组（FPL64176）（HF/LF+FPL）、高/低氟+L-型钙通道拮抗剂组（Nifedipine）（HF/LF+NIF）.染氟6个月,染氟结束前1周,HF/LF+FPL和HF/LF+NIF组分别每天腹腔注射激动剂或拮抗剂（5 mg·kg^-1·d^-1）.用TUNEL法检测小鼠海马CA₁区细胞凋亡水平,用Western Blot法检测细胞膜L-型钙通道Cav1.2、Ca²⁺信号通路分子和下游凋亡调节相关分子蛋白表达水平等.结果表明,与对照组比,HF/LF组小鼠海马组织抗氧化能力显著降低（p<0.05或p<0.01）,细胞凋亡水平极显著上升（p<0.01）,Cav1.2与Bcl-2蛋白表达水平显著下降（p<0.05或p<0.01）,Ca²⁺信号转导通路CaM、CaMKII和促凋亡Bax、Bax/Bcl-2蛋白表达水平显著上升（p<0.05或p<0.01）.注射FPL64176的小鼠海马细胞和上述分子指标的损伤加剧,而注射NIF对海马细胞和上述分子蛋白表达有一定的逆转作用.提示L-型钙离子通道介导了氟暴露致小鼠海马损伤,氟暴露致海马细胞膜L-型钙离子通道Cav1.2蛋白、细胞内Ca²⁺信号转导通路分子和下游凋亡调节相关蛋白表达异常是其分子机制之一,而L-型钙通道拮抗剂NIF可能是一种新型有效的抗氟药物.     

电解强化人工湿地处理低碳氮比污水的效能及机制

针对人工湿地对低碳氮污水处理效果差这一问题,本研究构建了电解强化潮汐流人工湿地系统,通过对比电解强化前后湿地系统脱氮除磷的效果,从微生物群落结构及污染物电化学去除机制等角度揭示电解潮汐流人工湿地强化脱氮脱磷的机制.研究结果表明：电解潮汐流人工湿地对废水中NH₄⁺-N、TN和TP的去除率（分别为88.30%、82.10%和87.74%）均高于未强化的湿地系统.纯电解过程对氨氮的去除没有影响,但是对硝态氮具有还原作用.相比于未强化的湿地系统,电解潮汐流人工湿地阳极附近基质中含有更多的铁氧键、磷氧键、羟基聚合铁等含磷沉淀物,细菌群落结构更为丰富多样,异养反硝化细菌和基于氢气的自养反硝化细菌（Rhodoblastus）丰度都较高,从而实现氮磷的高效同步去除.     

长江经济带生态环境保护的若干战略问题

长江经济带发展是国家区域协调发展的重大战略之一,要保护长江生态环境,走生态优先、绿色发展之路.当前,长江经济带经济增速放缓,产业结构持续优化,城镇化处于快速发展阶段后期;主要污染物排放强度下降,水环境质量改善,但水生态状况堪忧,生态环境质量持续稳定改善进入攻坚期.通过对社会经济和生态环境形势的研判,阐述了长江经济带生态环境保护的战略需求和目标,并提出了四项战略.结果表明:①长江经济带生态环境保护的战略需求从单一要素、单一指标、部分区域转向水生态环境的系统保护和综合修复.②生态环境保护的战略目标由水环境质量改善转向水生态环境安全提升,未来将逐步转向生态环境健康改善.③空间管控战略需要整合多项区域规划,研究构建流域与区域协同、水陆统筹、山海一体的统一的长江经济带生态环境空间单元划分体系.④产业绿色发展战略的核心是在影响水生态环境安全的相关产业领域加强防控.⑤科技创新战略要突出科技平台的作用,推进数据、人才、技术、成果的汇集和创新,实现生态环境保护由投资驱动向科技创新驱动转型.⑥现代治理能力提升战略要求长江经济带建成生态文明先行示范带,率先完善生态文明制度体系,构建生态环境治理体系和提升生态环境治理能力.研究显示,把握长江经济带生态环境保护的战略需求和目标,推行空间管控、产业绿色发展、科技创新和现代治理能力提升战略,能更加有效地支撑长江经济带和长江三角洲一体化的发展.      

Survival of Nucella lapillus in a tributyltin-polluted area in west Brittany: a further example of a male genital defect (Dumpton syndrome) favouring survival

A male genital defect was reported in a Nucella lapillus (L.) population at Dumpton Gap (England). This defect was termed Dumpton syndrome (DS) and appears to be a genetic feature. Its main characteristic is the absence of penis (aphally) in males and in females. In 1992, such a phenomenon was discovered in populations in the vicinity of Brest (Brittany, France). DS-affected females exhibit fewer tributyltin-induced imposex characteristics than expected in normal individuals. The percentage of female sterilization is thus lower, favouring population survival. In consequence, the DS is considered to be a pollution-resistance feature. Comparison with the Dumpton population revealed similarities and differences in the DS characteristics. It is thus hypothesized that the DS observed at the two locations is due to two different biological mechanisms. Indeed, aphallic males with a split prostate were observed but no underdevelopment of their vas deferens and testis was noted in the present study. In this gonochoristic gastropod species, the most DS-affected males in Brest possess an ovotestis and it is thus hypothesized that feminity is remnant in N. lapillus. Incidence of abnormality is ten times higher in females than in males. This suggested that a sex-difference operates in the Brest phenomenon.     

Government plans and farmers intentions: a study on forest land use planning in Vietnam

In 1998, the Vietnamese National Assembly approved a Five Million Hectare Reforestation Program, (5MHRP) 1998-2010. It would increase forest cover by some 45%, use barren hills, produce wood, and generate socioeconomic development. It would, however, also put demands on Vietnamese planning. Experiences from a former development project and two case studies from a commune and village are used as a basis for analyzing the planning system. The study describes the objectives and strategies of government and farmers in one commune and one village and analyzes how planning data influence scenarios on future development. Official planning data do not reflect reality but are derived through negotiations. In the commune and village studied, it would be difficult for the 5MHRP to materialize, as most of the forest land, officially not yet used, is actually used for food production. The approach and method used by the study offers alternatives to current planning practices.