(3-chloropropyl)triethoxysilane

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

2 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

2 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.2 mg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

200 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

92 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.92 mg/kg sediment dw

Assessment factor:

10

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

17.5 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Additional information

Short-term ecotoxicity data for three trophic levels are available for(3-chloropropyl)triethoxysilane. The relevant values are:

Fish:LC50 (96 h): 80 mg/l; NOEC: 58 mg/l

Daphnia: EC50 (48 h): 21.2 mg/l; NOEC: 2.15 mg/l (Mitterer, K.-E. 2002)

Daphnia: EC50 (48 h): 140 mg/l; NOEC: 100 mg/l (Hüls 1993)

Algae: EC50 (72 h): >819 mg/l; NOEC 237 mg/l

In addition, a 21-day NOEC value of ≥100 mg/L has been determined for the effects of(3-chloropropyl)triethoxysilaneon mortality and reproduction of Daphnia magna when expressed in terms of nominal concentrations. The result has been reinterpreted by the reviewer in terms of the mean measured concentration of the test substance to give a NOEC of ≥66 mg/L.

The PNEC is based on taking the NOECs derived in the algal test and long-term test with invertebrates into account and applying an assessment factor of 50. It is noted that the NOEC derived in the long-term invertebrate test is higher than the EC50 values derived in the short-term invertebrate and fish tests. The long-term invertebrate result has however been used as the basis for setting the PNEC for the following reasons:

·         Both invertebrate tests are assigned reliability 1 but the test design used in the long-term test is more robust in terms of the numbers organisms that are exposed in each treatment.

·         The apparent discrepancy in the relationship between the two results can be explained to a large degree by the shallow nature of the dose-response relationships in both tests which means that there is scope for overlap of the EC50 and NOEC values when other sources of variability in the test results are taken into account.

·         There is no significant difference in the susceptibility of fish and invertebrates indicated in the short-term tests; therefore, there is no reason to expect that a long-term fish test would give a lower NOEC than the long-term invertebrate study.

Therefore, PNECaquatic is≥100/50 =≥2 mg/l.

Conclusion on classification

It is proposed that the substance should not classified in the EU based on LC50 or EC50 values from short term tests on fish, Daphnia and algae of 80, 21.2 or 140 mg/l (two different studies), and >819 mg/l, respectively, and a 21-day NOEC of ≥100 mg/l (nominal concentration) for Daphnia magna (effects of the test substance on mortality and reproduction). The substance has a log K_owof 3.13 and is not biodegradable.