Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Studies for terrestrial toxicity have been waived based on the following argumentation:

Xylanase has a very low Henry’s law constant (<10-4) and a low octanol-water partition coefficient (<0). Therefore, exposure to agricultural soil via sludge application as well as via aerial deposition is very low. Exposure to soil may occur if waste water is discharged off via septic tank. According to the EUSES calculations, less than 0.01% of enzymes entering a sewage treatment plant (STP) will bind to sludge. As enzymes are degradable at both aerobic and anaerobic conditions, a high rate of inactivation and degradation of xylanase in soil is expected. Assuming a degradation rate in soil at the same level as degradation rate in surface water, i.e. a half life of 5 hours, calculations show that the risk characterization ratio (RCR) for soil is 25% below the RCR for the surface water. Thus xylanase applied to agricultural soils via sludge application do not present a risk to the soil compartment due to sludge application. Enzymes may potentially leach into the soil, if waste water is discharged to a septic tank. The chemical safety assessment based on the equilibrium partitioning method shows that xylanase does not exhibit a risk to soil living organisms in such situation.