lysophospholipaseIUBMB 3.1.1.5

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

18 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

180 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

1.8 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:

2.8 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). The short-term toxicity of lysophospholipase to fish and crustacean was not conducted, however, an enzyme (IUB 3.1.1.3) from the same class was used for read-across.

Cutinase was tested on rainbow trout and the 96 hour LC50 value was > 68.3 mg active enzyme protein (aep)/L and the no observed effect concentration 11.2 mg aep/L. Cutinase was also tested on invertebrate Daphnia magna and no immobilization was seen in concentrations up to 37.4 mg aep/L, as well as on blue green algae and did not inhibit the growth in concentration up to 41.3 mg aep/L. Lipolase was tested on blue green algae and the no observed effect concentration was 7.4 mg aep/L. The 72h EbC50 is 17.6 mg aep/L and the ErC50 is 18 mg aep/L. Given the similarity between the enzymes, it is expected that lysophospholipase will have similar short-term toxicity values to fish, invertebrates and algae. Inhibition control carried out 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 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, lysophospholipase is not considered to be toxic to microorganisms.

The lowest EC50 value was extrapolated from a read-across from an enzyme from the same class, lipase, and it was calculated to be 18 mg active enzyme protein/L in a test with algae. This value 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 active enzyme protein 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 lysophospholipase 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 test substance is thus not expected.

As no soil ecotoxicity data are available for lysophospholipase, the PNEC for soil is based on the PNEC for surface water using the equilibrium partitioning method. PNEC soil was estimated to 2.5 µg active enzyme protein/kg soil ww.

Lysophospholipase is not expected to cause any significant secondary poisoning as it is ready biodegradable and has no bioaccumulation potential. Furthermore, as lysophospholipase 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 aquatic toxicity studies and the ready biodegradation of the enzyme, lysophospholipase is not classified.