Dynamic Behavior of Fluorescent Whitening Agents in Greifensee:  Field Measurements Combined with Mathematical Modeling of Sedimentation and Photolysis

Abstract

The dynamic behavior of the two fluorescent whitening agents (FWAs) that are currently used in laundry detergents in Switzerland (DAS 1, a diaminostilbene, and DSBP, a distyrylbiphenyl) has been evaluated quantitatively during 1 year for Greifensee, a small lake in Switzerland, by using a one-box model and simulation software (MASAS) for modeling organic pollutants in lakes. Both the onebox model and the one-dimensional simulation were based on (i) independently evaluated processes affecting the fate of FWAs and (ii) measured FWA concentrations in the lake. The relevant processes were derived from literature data and from measurements in the lake and in its tributaries. Besides loading from tributaries, only photodegradation (responsible for 53% and 81% of the elimination of DAS 1 and DSBP, respectively), sorption/ sedimentation (20% and 9%), and flushing (27% and 10%) were found to be relevant for FWAs in Greifensee. In particular, no evidence was found for other degradation processes such as biodegradation or hydrolysis. During 1 year, concentration depth profiles were measured above the deepest point of the lake in intervals of 4 weeks. The measured FWA concentrations were between 50 and 120 ng L -1 (DAS 1) and between 10 and 110 ng L -1 (DSBP), with maximum values in the thermocline during summer. Evidence was found that these maximum values originated from subsurface loading occurring in summer at levels of 4-8 m depth. This study is one of the first field validations for photochemical degradation rates measured in the laboratory. FIGURE 1. Structures of the FWAs included in this study. DAS 1, 4,4′-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]stilbene-2,2′disulfonate; DSBP, 4,4′-bis(2-sulfostyryl)biphenyl.

Occurrence of microplastics in the coastal marine environment: First observation on sediment of China

“…For another hand, it have been found that FWAs are widely distributed in sediment (Managaki and Takada, 2005). While Stoll et al (1998) had ever set a mathematical modeling to analyze the dynamic behavior of FWAs, including photodegradation, sorption/sediment and flushing. All these indicates natural organic matter adsorbed FWAs may be misunderstood as microplastics.…”

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.…”

Field Measurement of Fluorescent Dissolved Organic Material as a Means of Early Detection of Leachate Plumes

“…This decrease in fluorescence was considered a good indication of the presence of a mixture of FWAs within the water samples (Baker 2002). Sewage disposal is also typically high in FWAs, and numerous studies have utilised these characteristics to trace sewage impact in rivers and lakes (Close et al 1989;Stoll et al 1998;Mostofa et al 2010;Yamaji et al 2010), and the presence of FWAs in sewage is expected to be similar to FWAs which may be present in landfill leachate. The fate of FWAs in groundwater has not been documented in detail.…”