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Environmental fate & pathways

Endpoint summary

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Additional information

No monitoring data or specific field studies are available for Leucophor 1111X, nevertheless many data are existing and have been developed for analogous substances Stilbene Fluorescent Whitening Agents.

The analogous substance 04, is a monoconstituent morpholino derivative. It is produced in higher quantities and almost exclusively used in the detergency field, where the environmental exposure and impact is at the highest levels because of the dispersive domestic use.

The monitoring and field studies results of the analogous substance 04 can therefore be assumed as conservative representative for the substance under investigation.

Isomerization of analogous 04 in sewage was found to be very fast. A simple model was used to simulate the partitioning of the substance under the influence of sunlight. ln solutions with low particle content, the ratio is dominated by the photochemically favoured (Z)-isomer. With increasing particle content, the more strongly adsorbing (E)-isomer is favoured and becomes the dominant species. Very good agreement between model calculation and field data is obtained for primary and secondary effluent. Primary sludge is settled before isomerization can take place.

From field data the following conclusions concerning the behaviour and fate of analogous 04 in a mechanical sewage treatment plant can be drawn:

(I) elimination of test substance from wastewater occurs during both mechanical and biological treatment.

(II) overall removal rate of 98 % was observed.

(III) elimination is due to adsorption to primary and activated sewage sludge and the observed elimination, rate is consistent with the individual sorption behaviour of the test item as investigated in laboratory experiments.

(IV) no evidence for biodegradation of substance was found during the (aerobic) biological treatment of wastewater with activated sludge and during anaerobic-mesophilic digestion of raw sewage sludge.

(V) the substance removed during wastewater treatment is thus quantitatively recovered in anaerobically digested, sewage sludge.

Leucophor 1111X is a Stilbene Fluorescent Whitening Agent (SFWA), 4,4’-bis(1,3,5-triazinyl-2-yl)amino)stilbene-2,2’-disulfonic acid (DAS) derivative. Substances belonging to this class are very soluble in water and they are characterized by a negative log kow. Based on the chemical structure and its functionalisation, the SFWAs are expected to be able to interact with the soil substrates chemically, however, it cannot be established the strength of this interaction; adjusting the salt content and pH conditions, SWAs can be efficiently removed in the STP plants. The distribution of a chemical between soil and aqueous phases is a complex process depending on a number of different factors: the chemical nature of the substance, the characteristics of the soil and climatic factors such as rainfall, temperature, sunlight and wind. The available information suggests that Stilbene Fluorescent Whitening Agents have not an univocal adsorption/desorption behaviour describable by a range of values: they are expected to be more or less mobile depending on the soil type and conditions.

Assuming biodegradation processes are not significant, the only elimination processes are removal and photodegradation.

The analogous 04 shows seems to be able to interact with the organic substrate and this capability lead to a high extent of elimination in the sewage treatment plants, due to adsorption onto the sewage sludge. From this point of view, environment conditions, i.e. pH, temperature, particle's surface, play a crucial role.

Monitoring data about the STPs efficacy are available and the results on the investigation about the efficacy of the STPs confirm that the substance can be removed in appreciable percentage.