Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The estimated half-life (DT-50) of the substance in air is 25.6 days.

The substance is hydrolytically stable in water at ambient pH values (pH 7) and pH 9. It is unstable at pH 4 and 50°C and 60°C with DT-50 values of 27.0 ± 2.6 s and 21.3 ± 1.8 days. At 70°C, the estimated DT-50 is 9.6 ± 3.5 days.

The substance will not be degraded by direct photolysis in water, since it does not absorb light at wavelengths≥ 290 nm.

The substance is not readily biodegradable.

The substance has an estimated log Koc of 0.51. This indicates that the substance is not or not significantly binding to soil, sediments, sludge or other matrices susceptible for binding, with which the substance will come into contact. The lack of (significant) adsorption indicates that the substance is highly mobile, e.g., by run-off from all kinds of solid surfaces and by leaching through the ground, if reached.

The Henry’s Law constant of CAS 127-52-6, the main constituent of “CAS 127-52-6 trihydrate” is 0.791 Pa m3/mole, which corresponds to 7.81 x 10-6 (i.e., 0.00000781) atm m3/mole or 3.19 x 10-4 (unitless). Hence, CAS 127-52-6 is considered slightly volatile from water at ambient temperature. Since the water solubility of CAS 127 -52 -6 is very high, it is unlikely that CAS 127 -52 -6 co-evaporates with water under evaporation conditions.

Though the substance is hydrolytically stable in water at ambient pH, it is unstable under application conditions, depending on the concentration of the application solution. The substance is applied as disinfectant in order to eliminate harmful matters. During application under disinfection conditions, 0.01 g/L aqueous solutions are decomposition/dechlorinated completely to its dechlorinated form benzenesulfonamide (BSA) within 5 hours. 90% decomposition/dechlorination is reached within 30 minutes. Taking into account that the worst case application concentration is 50 g/L and assuming a realistic worst case dilution factor of at least 500 into waster waters (which are typically loaded highly with bacteria and organic waste) it is obvious that no test material will reach the STP nor the aquatic environment. Complete dechlorination was confirmed by treatment of surfaces with 50 g/L, as < 0.025 ppm chlorine was detected 10 cm above the treated surfaces, under worst case ventilation conditions.