Mannanase, endo-1,4-β-

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

55.5 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

555 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

5.55 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

65 000 µg/L

Assessment factor:

1

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

no exposure of sediment expected

Sediment (marine water)

Hazard assessment conclusion:

no exposure of sediment expected

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

6.64 µg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The aquatic toxicity data were obtained from short term toxicity studies in species representing three trophic levels (i.e. algae, crustacean and fish).

Fish: Under the conditions of the test, Mannanase, batch PPE6432 was not found to be acutely toxic to rainbow trout (Oncorhynchus mykiss). Consequently, the 96-hour LC50 value for mannanase could not be calculated and must be > 105.8 mg enzyme concentrate dry matter/L (equivalent to 55.5 mg active enzyme protein/L). The "no-observed effect concentration" was the highest concentration 105.8 mg enzyme concentrate dry matter/L.

Daphnia: Under the conditions of the test, Mannanase, batch PPE6432 was not found to be acutely toxic to Daphnia magna at a nominal concentration of 105.8 mg enzyme concentrate dry matter/L, equivalent to 55.5 mg active enzyme protein (aep)/L. The 'No observed effect concentration' was the highest concentration 105.8 mg enzyme concentrate dry matter/L.

Algae: Under the conditions of the test, the 72h EC50 value of Mannanase, batch PPE6432 to R. subcapitata growth rate could not be determined and must be >105.8 mg enzyme concentrate dry matter/L (equivalent to 55.5 mg aep/L), based on nominal concentrations. The No Observed Effect Concentration (NOEC) for both growth rate and area under the growth curve was calculated as 26.5 mg enzyme concentrate dry matter/L (equivalent to 13.9 active enzyme protein).

Inhibition control carried out with non-proteolytic enzymesin the test of ready biodegradability showed no inhibition of the activated sludge inoculum at an enzyme concentration above the expected levels in inlet to sewage treatment plants (STPs). Monitoring of enzymes in the inlet to municipal STPs (in Denmark) resulted in concentrations of less than 2 µg active enzyme protein (aep)/L which are below the initial concentration used in tests for ready biodegradability, where no inhibitory effects were observed. It is concluded that a study on activated sludge respiration inhibition does not need to be conducted. Therefore, the test enzyme is not considered to be toxic to microorganisms.

The EC50 for Mannanase was > 105.8 mg enzyme concentrate dry matter/L, equivalent to 55.5 mg active enzyme protein (aep)/L was used for PNEC derivation and the assessment factors 1000 and 10000 were applied for fresh and marine water, respectively.

The PNEC value for STP is based on actual measurements of enzyme concentration in STP connected to manufacturing site. Up to 65000 µg aep/L were detected in STP connected to manufacturing site and since there was no negative impact observed, this concentration is the estimated PNEC value for STP.

PNEC values for sediment exposure have not been derived because the enzyme is readily biodegradable, highly water soluble and has a very low potential for adsorption to sediments. Exposure of the sediment to toxicologically significant concentrations of the enzyme is thus not expected.

As no soil ecotoxicity data are available for the test enzyme, the PNEC for soil is based on the PNEC for surface water using the equilibrium partitioning method. PNEC soil was estimated to 6.64 µg active enzyme protein/kg soil ww.

The enzyme is not expected to cause any significant secondary poisoning as it is ready biodegradable and has no bioaccumulation potential. Furthermore, as the test enzyme is a protein it is expected to be degraded in the gastrointestinal tract. Thus, PNEC oral is not relevant.

Conclusion on classification

The EC50 for Mannanase was > 105.8 mg enzyme concentrate dry matter/L, equivalent to 55.5 mg active enzyme protein (aep)/L. The concentration tested in active enzyme protein is not high enough for classification.