Fate of Fluorescent Whitening Agents in the River Glatt

Abstract

With the use of computer simulation (AQUASIM), the dynamic behavior of the two fluorescent whitening agents (FWAs) that are currently used in laundry detergents in Switzerland (DSBP, a distyrylbiphenyl, and DAS 1, a diaminostilbene) has been evaluated quantitatively for the River Glatt, a small highly polluted stream in Switzerland. The one-dimensional simulation was based on independently determined photolysis and sorption rate constants, and measured FWA concentrations at the beginning of the studied river section and in two major tributaries (effluents of sewage treatment plants). Concentrations of FWAs were 0.4-1.2 µg/L in river water and 2.9-5.7 µg/L in sewage, respectively, with very little diurnal variation. Direct photolysis and partitioning between aqueous phase and sediment and macrophytes were identified as the most important processes affecting the fate of DSBP and DAS 1 in the river. Simulation of FWA concentrations with photolysis as the only process yielded concentration traces with minima during daytime and maxima at night, which contradicted the observed uniform concentrations. By taking sediment/water exchange into account, good agreement between measured and modeled FWA concentrations was achieved. The observed removal of FWAs during transport (12 h residence time) was 31% and 12% for DSBP and DAS 1, respectively, corresponding to halflives of 0.9 and 2.7 d, respectively, under cloudless summer skies.

Photochemical, microbial and metal complexation behavior of fluorescent dissolved organic matter in the aquatic environments

“…It has been demonstrated that photoirradiation reduces the fluorescence intensity by decomposing fulvic and humic acids (Moran et al, 2000;Wu et al, 2005), tryptophan-like component (Moran et al, 2000;Mostofa et al, 2007b), and FWAs or household detergents (Poiger et al, 1999;Mostofa et al, 2005aMostofa et al, , 2010 in natural waters. On the other hand, microbial degradation has been observed to either enhance or decrease the fluorescence intensity in natural waters.…”

Developing Methods to Predict Chemical Fate and Effect Endpoints for Use Within REACH

“…A well studied example, where direct phototransformation in surface waters is a relevant environmental removal process, are fluorescent whitening agents, a class of high production volume chemicals widely used in laundry detergents and paper and cloth manufacturing [24][25][26][27]. A limited number of QSARs concerning very specific photoreactions, such as the photohydrolysis of aromatic halides [28], have been derived to date.…”

Distribution and fluxes of fluorescent whitening agents discharged from domestic wastewater into small rivers with seasonal changes of flow rates

“…Their widespread and massive usage and their persistent nature allow FWAs to be ubiquitously detected in wastewaters and in natural rivers, lakes, and oceans. For example, FWA concentrations are at a level of a few micrograms per liter (µg l −1 ) in sewage effl uent (Poiger et al 1998) and rivers Poiger et al 1999;Hayashi et al 2002;Hayakawa et al 2005) and at 0.1 µg l −1 in inland bays (Hayashi et al 2002) and lakes Yamaji et al, in preparation). Detergent surfactant, i.e., linear alkylbenzenesulfonate, is so biodegradable that it is not detected widely in natural waters as are FWAs.…”

“…Early studies of FWAs in Switzerland provided basic information on their distribution and behavior in rivers and lakes Poiger et al 1999). FWA concentrations in Swiss rivers were dependent on the discharge from sewage treatment plants that serviced a large population in the catchments, and from chemical plants manufacturing FWA in Switzerland for commercial export.…”

“…Concentrations of FWAs in small-scale rivers are not signifi cant in Switzerland because the nation's sewage treatment system covers 96% of its population (OECD 2004). As for the behavior of FWAs in rivers, Poiger et al (1999) estimated seasonal elimination of FWA in the River Glatt using a computer simulation model. They found that the simulated FWA levels controlled by sunlight photolysis were similar to the levels observed in the river.…”