低温低浊微污染水源水预氧化处理工艺设计

选用预氧化处理工艺以提高混凝絮凝效果,减少停留时间从而实现在小型设备中较高的处理量;占地面积小且速度快的气浮池代替了普通的沉淀池,并在混凝沉淀处理药剂和消毒处理药剂上选择了在低温条件下效果好的.     

Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism

Understanding the degradation behavior of azo dyes in photocatalytic wastewater treatment is of fundamental and practical importance for their application in textile-processing and other coloration industries. In this study, quantum chemistry, as density functional theory, was used to elucidate different degradation pathways of azo pyridone dyes in a hydroxyl radical (HO^?)-initiated photocatalytic system. A series of substituted azo pyridone dyes were synthesized by changing the substituent group in the para position of the benzene moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The effect of dye molecular structure on the photocatalytic degradation reaction mechanism was analyzed and quantification of substituent effects on the thermodynamic and kinetics parameters was performed. Potential energy surface analysis revealed the most susceptible reaction site for the HO^? attack. The calculated reaction barriers are found to be strongly affected by the nature of substituent group with a good correlation using Hammett σ_p constants and experimentally determined reaction rates. The stability of pre-reaction complexes and transition state complexes were analyzed applying the distortion-interaction model. The increased stability of the transition state complexes with the distancing from the substituent group has been established.     

Environmental chemical study on the marsh of Fatimid cemetery at Aswan City,Egypt

ＩｎｔｒｏｄｕｃｔｉｏｎＡｓｗａｎｇｏｖｅｒｎｏｒａｔｅ ,Ｅｇｙｐｔ ,ｉｓｆａｍｏｕｓｆｏｒｂｙｍｏｎｕｍｅｎｔｓ (Ａｎｃｉｅｎｔ,ＣｏｐｔｉｃａｎｄＩｓｌａｍｉｃ) .Ｔｈｅｆｏｕｎｄａｔｉｏｎａｒｅｏｆｔｈｅｆｉｒｓｔｉｍｐｏｒｔａｎｃｅａｎｄｃａｒｅｓｈｏｕｌｄｂｅｔａｋｅｎｔｏｓｅｅｔｈａｔｔｈｅｙａｒｅｃｏｎｓｏｌｉｄａｔｅｄａｎｄｐｒｏｔｅｃｔｅｄａｓｆｏｒａｓｐｏｓｓｉｂｌｅｆｒｏｍｔｈｅｉｎｆｉｌｔｒａｔｉｏｎｏｆｗａｔｅｒ.Ｗａｔｅｒｉｓａｍａｊｏｒｃａｕｓｅｏｆｄａｍａｇｅ ,ｎｏ…     

四川省环境科学学会环境医学专委会学术交流会在攀枝花召开

四川省环境科学学会环境医学专委会与省环境诱变剂学会和卫生毒理专委会于 2 0 0 0年 11月 2 8日至 12月 1日在攀枝花市园林宾馆联合召开了学术交流会。参加这次学术交流会有来自四川省和重庆市大专院校、省各级卫生防疫站、省环保科研院等单位的代表 70多人。共收到论文 87篇 ,论文包括饮用水卫生、公共场所卫生监督、环境卫生调查与检测、环境毒理和卫生毒理等部分。与会代表进行了认真地学术交流 ,并结合环境医学的科研和实际工作中的问题进行了深入讨论。会上还有 8位专家作了综述报告和专题讲座。这次学术交流会内容丰富广泛 ,讨论气氛…     

Modeling the e ects of constructed wetland on nonpoint source pollution control and reservoir water quality improvement

This article describes the integrated modeling approach for planning the size and the operation of constructed wetlands for maximizing retention of nonpoint source pollutant loads and reservoir water-quality improvement at a catchment scale. The experimental field-scale wetland systems (four sets, 0.88 ha each) have been in operation since 2002, where water depth was maintained at 30–50 cm and hydraulic loading rate was at 6.3–18.8 cm/day. The wetland system was found to be adequate for treating polluted stream water with stable removal e ciency even during the winter. The integrated modeling system (modified-BASINS) was applied to the Seokmoon estuarine reservoir watershed and calibrated with monitoring data from constructed wetland, stream, and reservoir. The calibrated integrated modeling system estimated that constructing wetlands on 0.5% (about 114 ha) of the watershed area at the mouth of reservoir could reduce 11.61% and 13.49% of total external nitrogen and phosphorus loads, respectively. It also might improve the nitrogen and phosphorus concentration of the reservoir by 9.69% and 16.48%, respectively. The study suggested that about 0.1%–1.0% of the watershed area should be allocated for constructed wetland to meet specified water-quality standards for the estuarine reservoir at the polder area where land use planning is relatively less complicated.     

元古宙海水的稳定同位素组成发生过大的变化了吗?

古元古代罗克内斯特组(1.93～1.89Ga)的海相碳酸盐相对于较年轻且形成于类似沉积环境的新元古代海相碳酸盐大量亏损δ~(18)O(约8‰)。广海海相组分的同位素数据叠加了两种同位素趋势。第一种趋势包括早期潮坪沉积物的稳定化作用,以及富δ~(18)O蒸发孔隙流体可能发生的回流型白云岩化作用。对于在同位素成分上δ~(18)O值较低的第二种趋势,它是广海海相与大气降水(混合带)接触或在埋藏的较高温度条件下白云岩化作用期间形成的,由此导致了块状孔隙吸留胶结物的沉淀。 最富集同位素的鲕粒均为保存最好的标准海相组分,因而可能表明海水的δ~(18)O值在1.9Ga时约为-9.75‰±1.0‰(SMOW)。为了解释所推论的海水δ~(18)O值在1.9～1.0Ga期间存在8‰的正向漂移,海水的这一组成要求在高温下海水与玄武岩之间存在氧同位素交换平衡以及低温风化作用有过较大的变化。很可能亏损的δ~(18)O值表明在1.9Ga时表层海水具有大约30～35°C的较高温度。其重碳同位素δ~(13)C值为+1.75‰,比先前根据全岩数据所报道的新元古代海水更富集δ~(13)C。     

某些太古界岩石的金含量及其与后生含金石英脉矿床的可能关系

<正> 引言 太古界花岗岩-绿岩地体中的金矿化每年可提供大约200t金。现在世界金年产量大约为1300t。 太古界金矿床包括块状硫化物、古砂矿和条带状铁建造,其中最重要的一类是与石英脉伴生的后生矿化。 在空间上与太古界绿岩有密切关系的含金石英脉,已知在世界范围内都有产出。例如南非的巴伯顿山地、西澳大利亚卡尔古利矿区的戈尔登迈尔以及加拿大苏必利尔构造省的阿比蒂比绿岩带。 直至约25年前,人们乐于用来解释金矿脉     

Nitrogen cycling of atmosphere-plant-soft system in the typical Calamagrostis angustifolia wetland in the Sanjiang Plain,Northeast China

The nitrogen(N)distribution and cycling of atmosphere-plant-soil system in the typical meadow Calamagrostis angustifolia wetland (TMCW)and marsh meadow Calamagrostis angustifolia wetland(MMCW)in the Sanjiang plain were studied by a compartment model.The results showed that the N wet deposition amount was 0.757 gN/(m~2.a),and total inorganic N(TIN)was the main body (0.640 gN/(m~2.a)).The ammonia volatilization amounts of TMCW and MMCW soils in growing season were 0.635 and 0.687 gN/m~2, and the denitrification gaseous lost amounts were 0.617 and 0.405 gN/m~2,respectively.In plant subsystem,the N was mainly stored in root and litter.Soil organic N was the main N storage of the two plant-soil systems and the proportions of it were 93.98% and 92.16%, respectively.The calculation results of N turnovers among compartments of TMCW and MMCW showed that the uptake amounts of root were 23.02 and 28.18 gN/(m~2.a)and the values of aboveground were 11.31 and 6.08 gN/(m~2.a),the re-translocation amounts from aboveground to root were 5.96 and 2.70 gN/(m~2.a),the translocation amounts from aboveground living body to litter were 5.35 and 3.38 gN/(m~2.a),the translocation amounts from litter to soil were larger than 1.55 and 3.01 gN/(m~2.a),the translocation amounts from root to soil were 14.90 and 13.17 gN/(m~2.a),and the soil(0-15 cm)N net mineralization amounts were 1.94 and 0.55 gN/(m~2.a), respectively.The study of N balance indicated that the two plant-soil systems might be situated in the status of lacking N,and the status might induce the degradation of C.angustifolia wetland.     

Dietary exposure to di-isobutyl phthalate increases urinary 5-methyl-2′-deoxycytidine level and affects reproductive function in adult male mice

Phthalates are a large family of ubiquitous environmental pollutants suspected of being endocrine disruptors. Epidemiological studies have associated phthalate metabolites with decreased reproductive parameters and linked phthalate exposure with the level of urinary 5-methyl-2′-deoxycytidine(5mdC, a product of methylated DNA). In this study, adult male mice were exposed to 450 mg di-isobutyl phthalate(DiBP)/(kg·day) via dietary exposure for 28 days. Mono-isobutyl phthalate(Mi BP, the urinary metabolite) and reproductive function parameters were determined. The levels of 5mdC and 5-hydroxymethyl-2′-deoxycytidine(5hmdC) were measured in urine to evaluate if their contents were also altered by DiBP exposure in this animal model. Results showed that DiBP exposure led to a significant increase in the urinary 5mdC level and significant decreases in sperm concentration and motility in the epididymis, accompanied with reduced testosterone levels and downregulation of the P450 cholesterol side-chain cleavage enzyme(P450scc) gene in the mice testes. Our findings indicated that exposure to DiBP increased the urinary 5mdC levels,which supported our recent epidemiological study about the associations of urinary 5mdC with phthalate exposure in the male human population. In addition, DiBP exposure impaired male reproductive function, possibly by disturbing testosterone levels; P450scc might be a major steroidogenic enzyme targeted by DiBP or other phthalates.     

三峡库区回水区营养盐和叶绿素a的时空变化及其相互关系

为探讨三峡水库调度运行背景下,库区回水区营养盐和叶绿素a时空变化及其相互关系,于2013年5月~2014年5月在三峡库区北岸最大、也是库区水华频发的支流——澎溪河的回水区高阳平湖进行了定点和高频监测.结果表明水体热分层是高阳平湖水华发生的诱导因素.高阳平湖水体热分层发生于春季(3月初),消亡于夏末(9月中旬),冬季没有分层.2014年春季,随着水体分层的发生和发展,表层叶绿素a在69 d内从14.92μg·L-1骤增至183.73μg·L-1,并暴发水华,之后叶绿素a随着混合层深度增加而下降.水体没有分层时,表、中和底层营养盐浓度相近;水体分层之后,各层磷浓度有了明显差异,表层和底层总磷浓度相差(0.18±0.04)mg·L-1.高水位期(9月至次年4月),高阳平湖硝氮和溶解性磷高于低水位期(5~8月)的含量,分别占总氮、总磷浓度的71.4%~95.4%和42.7%~94.4%,是总氮和总磷的主要组成部分,干流倒灌输入的硝氮和溶解性磷是其主要来源.