Fluorescent Chemosensors Based on Spiroring-Opening of Xanthenes and Related Derivatives Xiaoqiang Chen, Tuhin Pradhan, Fang Wang, Jong Seung Kim,* and Juyoung Yoon* Departments of Chemistry and Nano Science and of Bioinspired Science (WCU), Ewha Womans University, Seoul 120-750, Korea State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China Department of Chemistry, Korea University, Seoul 136-701, Korea

Fluorescent chemosensors based on spiroring-opening of xanthenes and related derivatives.

Bioavailability, accumulation and effects of heavy metals in sediments with special reference to United Kingdom estuaries: a review

Organotin compounds are ubiquitous contaminants in the environment. The high biological activity of some compounds toward aquatic organisms lead to deleterious impacts in aquatic ecosystems. Here, the aquatic ecotoxicology of organotins is reviewed based on a multidisciplinary approach involving environmental chemical, toxicological, and ecological aspects. Basic results were obtained both with field and laboratory studies, and some of the most important recent results and conclusions are critically reviewed. The contamination of and fate in aquatic systems is reported and linked with effects at different levels of biological organization. Major emphasis is placed on the development of a concept of ecotoxicology that encompasses not only effect assessment alone, but also integrates environmental chemistry with aquatic toxicology. Thereby, the influence of speciation for bioavailability, basic modes of toxic action, and aquatic toxicity are discussed. This case study on organotins allows to a certain extent generalizations to ecotoxicology in general.

Ecotoxicology of organotin compounds.

Existing field data indicate that soot may significantly affect the environmental speciation of polycyclic aromatic hydrocarbons (PAHs). To expand hydrophobic partition models to include soot partitioning, we need to quantify fsc, the soot fraction of the solid matrix, and Ksc, the soot-carbon-normalized partition coefficient. To this end, we have developed a method that allows quantification of soot carbon in dilute and complex sedimentary matrices. Non-soot organic carbon is removed by thermal oxidation, and inorganic carbonates are removed by acidification, fol lowed by CHN elemental analysis of the residual soot carbon. The selectivity of the soot carbon method was confirmed in tests with matrices of known compostion. The soot quantification technique was applied to two sets of natural sediments, both previously analyzed for PAHs. The input histories of PAHs and soot recorded in a lacustrine sediment core followed the same general trends, and we thus infer a coupling between the two. Our measures of f...

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Quantification of the dilute sedimentary soot phase : Implications for PAH speciation and bioavailability

Sonochemical engineering is a field involving the application of sonic and ultrasonic waves to chemical processing. Sonochemistry enhances or promotes chemical reactions and mass transfer. It offers the potential for shorter reaction cycles, cheaper reagents, and less extreme physical conditions, leading to less expensive and perhaps smaller plants. The amount of things that can be accomplished with sonochemistry is, at this stage, only limited by the minds of those working in this exciting field. Existing literature on sonochemical reacting systems is chemistry-intensive, and applications of this novel means of reaction in environmental remediation and pollution prevention seem almost unlimited. For example, environmental sonochemistry is a rapidly growing area that deals with the destruction of organics in aqueous solutions. However, some theoretical and engineering aspects are not fully understood. This paper reviews the field comprehensively by combining the existing knowledge from chemistry with insi...

Sonochemistry: Environmental Science and Engineering Applications

Determination of tin(IV) and organotin compounds in natural waters, coastal sediments and macro algae by atomic absorption spectrometry

Automobile catalytic converters apparently release significant quantities of platinum and palladium to the roadside environment. Dust samples collected from broad-leaved plants contained as high as 0.7 ppm of platinum and 2.5 times less palladium. Rains may wash this concentrate into local water systems or the ocean. 8 references, 1 table.

Platinum and palladium in roadside dust.

A study was conducted to determine the relationships between metal and mineral contents of the Lake Michigan sediments and fluxes of charcoal, whose morphologies and surface characteristics are indicative of different combustion processes. Sediments deposited during 1930-1968 showed increasing concentrations of chromium, nickel, iron, aluminum, zinc, cobalt, lead, cadamium, and copper. After 1968, these concentrations decreased slightly. A similar profile was found for total charcoal concentration.

Impact of fossil fuel combustion on the sediments of Lake Michigan.

241Pu and241Am in sediments from coastal basins off California and Mexico

The U.S. Environmental Protection Agency (EPA) has been examining the potential of combining sonication with available measurement technologies for monitoring chlorinated hydrocarbons in water. The chloride ion (Cl - ) concentration, conductivity, and pH were measured before and after sonication. Cl - could be detected in aqueous solutions of 3-80 ppm carbon tetrachloride (CCl 4 ), chloroform (CHCl 3 ), and trichloroethylene (TCE) after 1 min of sonication. The increases of Cl - were accompanied by increases in conductivity and decreases in pH. The conductivity changes were higher than expected based on measured Cl - . Ion chromatography of solutions before and after sonication showed that formate ion (HCOO - ) was also formed. Other ions may have formed as well, but the concentrations were too low to allow their detection relative to HCOO - and Cl - . The results achieved serve as proof-of-principle and form a base of information which can be used to develop ultrasound monitoring methods for these compounds. Aromatic and polyaromatic chloro compounds represented by chlorobenzene (Ph-Cl) and polychlorobiphenyls (PCBs), respectively, did not release Cl - upon sonication as readily as did CCl 4 , CHCl 3 , and TCE. The PCB solutions gave no measurable changes in either Cl - , conductivity, or pH under the conditions of the experiments described

Vernon F. Hodge

Papers

Determination of tin(IV) and organotin compounds in natural waters, coastal sediments and macro algae by atomic absorption spectrometry

Platinum and palladium in roadside dust.

Impact of fossil fuel combustion on the sediments of Lake Michigan.

241Pu and241Am in sediments from coastal basins off California and Mexico

Use of sonochemistry in monitoring chlorinated hydrocarbons in water.