A field study of triclosan loss rates in river water (Cibolo Creek, TX)

Triclosan (TCS) is an anti-microbial agent used in down-the-drain consumer products. Following sewage treatment some of the triclosan will enter receiving waters. This study was designed to determine the die-away rate of triclosan released into a river as part of the sewage treatment plant effluent matrix. The study was conducted in Cibolo Creek, a moderate sized stream (discharge approximately 0.1 m(3)s(-1)) located in South Central Texas. Triclosan was analyzed from samples collected upstream of the sewage treatment plant, the sewage treatment plant effluent, and the river downstream from the effluent discharge. The first-order loss rate of parent triclosan from the water column was calculated from measured data (0.06 h(-1)) and this rate corresponded to a 76% reduction in triclosan over an 8 km river reach below the discharge. Mathematical modeling indicated that sorption and settling accounted for approximately 19% of total triclosan loss over 8 km. When removing sorption and settling, the remaining amount of triclosan had an estimated first-order loss rate of 0.25 h(-1). This loss rate was presumably due to other processes such as biodegradation and photolysis. These data show that loss of parent triclosan from the water column is rapid. Additional data are needed to fully document loss mechanisms.     

Quecksilbergasfeinreinigung mittels metall- und salzpartikelbelegter Tr?germaterialien (G/S-Reaktor) ?kotoxizit?t von Quecksilber und seiner Verbindungen

Zusammenfassung  Bei einer genauen Kenntnis der vorliegenden Quecksilberverbindungen und ihrem Verhalten im Rauchgaspfad thermischer Anlagen k?nnen durch entsprechende technische Ma?nahmen die Abscheideeffizienzen in trockenen, quasitrockenen und nassen Rauchgasreinigungsanlagen erheblich gesteigert werden, so da? der derzeit gesetzlich vorgeschriebene Emissionsgrenzwert von 50 μg/m³ [i.N.tr.] eingehalten und unterschritten wird. Die in den letzten Jahren unternommenen Aktivit?ten und Fortschritte bei der Reduzierung des Quecksilberaussto?es von thermischen Anlagen werden zusammenfassend dargestellt. Am Beispiel von tr?gerimmobilisierten metall- und/oder metallsalzpartikelbelegten Tr?germaterialien (G/S-Reaktoren) wird die selektive Entfernung des Quecksilbers bzw. dessen Verbindungen experimentell und theoretisch im Rauchgaspfad verdeutlicht. Aus der selektiven Abtrennung von Quecksilber und seinen Verbindungen in der Gasphase resultieren auch entsprechende ?kologische und ?konomische Vorteile, die den allgemein erkennbaren Trend der artspezifischen Abtrennung von Schadstoffen mit einer m?glichen Rückführung des Wertstoffes Quecksilber in den Wirtschaftskreislauf unterstützen.      

Canopy leaching of nutrients and metals in a mountain spruce forest

Precipitation and throughfall fluxes of major ions, nutrients (C, N, P), and metals (Al, Fe, Mn), and the chemical composition of litter fall and living plant tissue in Norway spruce stands (the Bohemian Forest; Czech Republic), were used to evaluate how microbial processes and decay of plant tissue in canopies influence canopy leaching (CL) of elements. Proton exchange for Mg²⁺, Ca²⁺, and K⁺ in decaying biomass and co-transport of Ca²⁺ and K⁺ out of plant cells with organic acid anions were the most likely processes contributing to CL of base cations. The CL of total P and N (and also NO₃^?) was minor. Important proportions of the N and P mineral forms were transformed to organic forms by microbial processes (primary and bacterial production), with the respective CL of ?13.9 and 16.4 mmol m^?2 yr^?1 for NH₄⁺ and organic N, and ?0.33 and 0.22 mmol m^?2 yr^?1 for dissolved reactive P (DRP) and organic P. Most of particulate P and N in throughfall (～90%) originated from microbial DRP and NH₄⁺ transformations, but particulate C mostly came from the fragmentation of plant tissue (58%). Among metals, CL was not observed for Al, was small for Fe (0.3 mmol m^?2 yr^?1), and greatest for Mn (0.9 mmol m^?2 yr^?1) due to leaching from decaying tissue by acidic precipitation.