Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.45 µg/L
Assessment factor:
1 000
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
4.5 µg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.045 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

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Chymotrypsin was tested for aquatic toxicity in invertebrates and algae:

Invertebrates:

- Chymotrypsin, batch PPA23785 was tested with Daphnia magna for 48 hours at a nominal concentrations up to 100 mg TOS/L. The EC50 value was calculated to be 2.8 mg aep/L.

Algae:

-Chymotrypsin, batch PPA23785 was tested for algal growth inhibition at a nominal concentrations up to 100 mg TOS/L. The ErC50 (72h) value was calculated to be mg 2.4 mg TOS/L equivalent to 0.45 mg aep/L.

Inhibition control carried out with non-proteolytic enzymes in 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 chymotrypsin was 0.45 mg active enzyme protein/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.

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

Based on the results for acute aquatic toxicity testing chymotrypsin is clasasified as acute toxic to aquatic organisms.