生活垃圾焚烧底灰对亚甲基蓝的吸附性能研究∗

垃圾焚烧底灰(MSWI底灰)是垃圾焚烧的副产品之一,将MSWI底灰应用于透水路基,不仅能满足透水路基强度和渗透性需求,还能吸附雨水径流中的有机污染物。以苏州七子山垃圾焚烧厂MSWI底灰为原料,通过吸附试验及扫描电子显微镜(SEM),对其作为透水路基材料的吸附性能及机理进行了研究。结果表明,MSWI底灰的微观结构为球状结构,具有较大比表面积,粒径小于7.6 mm的底灰比表面积约为10 m2/g。可溶盐的溶解也能够增加吸附点位,从而促进有机物的吸附。动力学模型和等温吸附模型揭示了吸附为单分子层吸附,吸附能够在200min内达到平衡。由于可溶盐的溶解,表面具有一定的非均匀性,非均匀系数为0.75。根据Langmuir等温吸附模型计算,其对亚甲基蓝的最大吸附量约为5.44 mg/g。     

Lobar holoprosencephaly: prenatal MR diagnosis with postnatal MR correlation

Holoprosencephaly is a congenital anomaly characterized by lack of cleavage of the prosencephalon. Although, relatively rare, it is the most common anomaly that involves both the brain and the face. Prenatal diagnosis of this anomaly using ultrasonography, particularly of the less severe forms, is difficult. Magnetic resonance imaging has recently become an important complement to US in prenatal diagnosis of CNS anomalies. We herein report a patient in whom, at 23 weeks of gestation, US suggested agenesis of the corpus callosum and in whom, at 24 weeks of gestation, MRI correctly diagnosed lobar holoprosencephaly, which was confirmed by a postnatal MRI at 3 weeks of age. Copyright © 2005 John Wiley & Sons, Ltd.     

Nonredundancy in the dispersal network of a generalist tropical forest tree

Plant species with generalized dispersal mutualisms are considered to be robust to local frugivore extinctions because of redundancy between dispersal agents. However, real redundancy can only occur if frugivores have similar foraging and ranging patterns and if fruit is a limiting resource. We evaluated the quantitative and qualitative contributions of seed dispersers for an endochorus mast-fruiting species, Prunus javanica (Rosaceae) in Khao Yai National Park, Thailand, to evaluate the potential redundancy of dispersers. Data were collected from tree watches, seed/fruit traps, and seed transects under and away from fruiting trees, feeding and seed deposition by gibbons (Hylobates lar), and evaluations of seed and first-year seedling survival. We identified three clusters of dispersers within the network. Most (>80%) frugivore species observed were small birds and squirrels that were not functional dispersers, dropping most seeds under or very near the tree crown, where seedling survival was ultimately nil. Monkeys (Macaca leonina) were low-quality, short-range dispersers, but they dispersed large numbers of seeds and were responsible for 67% of surviving first-year seedlings. Gibbons and Oriental Pied Hornbills (Anthracoceros albirostris) handled few fruits, but they provided the highest quality service by carrying most seeds away from the canopy to medium and long distances, respectively. Although there was overlap in the deposition patterns of the functional dispersers, they displayed complementary, rather than redundant, roles in seed dispersal. Satiation of all functional dispersers further limited their capacity to "replace" one another. Redundancy must be evaluated at the community level because each type of disperser may shift to different species in the non-masting years of P. javanica. Our results underscore the need for research on broader spatial and temporal scales, which combines studies of dispersal and plant recruitment, to better understand mechanisms that maintain network stability.     

Transfer of nutrients and labile metals from the continent to the sea by a small Mediterranean river

The contribution of small watersheds to coastal pollution in Mediterranean areas is still poorly known, and presents great variations along an hydrological year. This work deals with the characterization and quantification of Al, Fe, Zn, Cu, Pb, Si, NO(3)(-) and organic carbon transported from the continent to the sea by a small coastal river in the French Mediterranean area. Transported species were characterized both during rainy and dry periods. During non-rainy periods (base-flow), waters showed a low content of contaminants, whereas during heavy rain events, following dry periods, some metals and organic carbon reached concentrations that could affect biological populations. These contaminants were mainly found in the particulate fraction, originating from the runoff of surface waters, which represents the main process of pollution in urban areas.     

USE OF A PREDICTIVE MODEL IN EVALUATING WATER CONSUMPTION CONSERVATION1

ABSTRACT: The effectiveness of water conservation policies on reduction of water consumption was evaluated by use of a multiple regression predictive model. Data were obtained from eight Iowa communities, with regard to water consumption and water conservation policies adopted during the drought of 1977. The proposed model, which takes precipitation, temperature, month effects, and uniqueness of communities into account, is considered superior to the use of simple percent changes in evaluating the significance of reduction in water consumption due to conservation efforts. Among the variety of policies reviewed, mandatory policies with per capita restrictions were found to be most effective. However, voluntary conservation policies also resulted in significant reduction in some communities located in close proximity to other communities with severer water shortages. High credibility of local governments as to water shortage information was singled out as the most important factor in successful conservation by water resource policymakers of these communities. Use of the proposed predictive model for water consumption was demonstrated. Recommendations regarding future water conservation were made.     

节能型虹吸式滗水器的设计与应用

详细介绍了虹吸式滗水器的构成、特点及工作原理,结合理论和实践经验给出了虹吸式滗水器的设计、计算方法及关键设计参数,提出了常规使用方法,整套设备的设计全面而简单明了。     

无定型纳米TiO2吸附去除饮用水中的低浓度As(Ⅲ)

研究了纳米无定型TiO2颗粒对饮用水中低浓度的三价砷As(Ⅲ)吸附行为。纳米TiO2颗粒吸附剂的BET表面积为205 m2/g,计算的BJH吸附平均孔径为4.02 nm(4 V/A)。对起始As(Ⅲ)浓度为150μg/L的模拟含砷水,经过5h的吸附处理后残余浓度不足4μg/L,As(Ⅲ)去除率达到97%。反应起始阶段吸附速率较快,84%的As(Ⅲ)能够在20min内去除。As(Ⅲ)吸附动力学较好地符合拟二级动力学模式。最佳As(Ⅲ)吸附pH为9.3,低于此值,随酸性增加吸附速率有所降低;而高于此值的强碱性pH对吸附有强烈抑制作用。在平衡浓度较低的情形下(10～220μg/L),Lang-muir,Freundlich和Dubinin-Radushkevich(D-R)吸附等温式均可较好拟合吸附行为,但中性和弱碱性条件下更符合Fre-undlich吸附等温式;平衡浓度大于220μg/L,吸附容量随平衡浓度增加而迅速增加,最大吸附容量在低浓度下达到4.79 mg/g。     

Heavy metal pollution and forest health in the Ukrainian Carpathians

The Ukrainian Carpathians are characterized by high air pollution caused by emissions from numerous industries. We have been monitoring the state of forests in this region since 1989. The highest levels of tree defoliation (>30%) are found close to industrial emission sources and in the upper mountain forests of the Ivano-Frankivsk and Chernivtsi regions. This is caused by a combination of strong anthropogenic influences (pollution, illegal uses, recreation) as well as poor site and climatic conditions. In the Ivano-Frankivsk region, Cd and Mo accumulate in forest soils; Cr, Mo and Zn soil concentrations are higher than their limit levels; and Pb concentrations exceed toxic levels close to industrial areas (10% of the region territory). Local background levels of heavy metals are greatly exceeded in snow close to industrial regions. Analysis of correlation matrices shows that the chemical elements Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn occur at pollution levels in natural ecosystems in the Ukrainian Carpathians. Maximum concentrations of toxic elements occur in the oak forest zone; the most industrially developed area of the region. Toxic heavy metals in the Ukrainian Carpathians forests enter with precipitation and dustfall, then become fixed in soil and accumulate in leaves, needles of vascular plants and mosses. Concentrations of these metals decrease with altitude: highest in the oak forests, less in beech, and lowest in the spruce forest zones. However, some chemical elements have the highest concentrations in spruce forests; V in needles, As in snow, and Ba and Al in soils.     

Gas-liquid chromatograms of sesquiterpenes as finger prints for soft-coral identification

A possible additional means for aiding in the identification of soft corals based on their sesquiterpene composition, as determined by gas-liquid chromatography (GLC), is discussed. The use of this method for several species of Sinularia and Sarcophyton is illustrated. Several sesquiterpenes were identified, some of them for the first time from marine origin. Preliminary tests indicate that the sesquiterpene composition in the tested soft corals remained quite constant during different seasons of the year. It is suggested that such finger prints are produced by the corals themselves and not by the zooxanthellae, and that they are species-specific.     

Annual average radon concentrations in California residences.

A study was conducted to determine the annual average radon concentrations in California residences, to determine the approximate fraction of the California population regularly exposed to radon concentrations of 4 pCi/l or greater, and to the extent possible, to identify regions of differing risk for high radon concentrations within the state. Annual average indoor radon concentrations were measured with passive (alpha track) samplers sent by mail and deployed by home occupants, who also completed questionnaires on building and occupant characteristics. For the 310 residences surveyed, concentrations ranged from 0.10 to 16 pCi/l, with a geometric mean of whole-house (bedroom and living room) average concentrations of 0.85 pCi/l and a geometric standard deviation of 1.91. A total of 88,000 California residences (0.8 percent) were estimated to have radon concentrations exceeding 4 pCi/l. When the state was divided into six zones based on geology, significant differences in geometric mean radon concentrations were found between several of the zones. Zones with high geometric means were the Sierra Nevada mountains, the valleys east of the Sierra Nevada, the central valley (especially the southern portion), and Ventura and Santa Barbara Counties. Zones with low geometric means included most coastal counties and the portion of the state from Los Angeles and San Bernardino Counties south.