Benzaldehyde, 2-hydroxy-5-nonyl-, oxime, branched

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 217 (Soil Microorganisms: Carbon Transformation Test)

Deviations:

yes

Remarks:

Test temperature (25 °C) is slightly higher as recommended by OECD guideline (20 ° C +/- 2 °C). Test duration (40d) is longer than recommended by OECD guideline (28d). these deviations are not thought to compromise the test results.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 and 1000 mg/kg
- Sampling method: On removal from the incubator, the replicates were mixed thorougly and half the quantity was freeze-dried. After freeze-drying three sampßles of each treatment were analysed.

Vehicle:

yes

Details on preparation and application of test substrate:

AMENDMENT OF SOIL
- Type of organic substrate: Reconstituted soil was used comprising a mixture of mature sewage sludge compost (1/3 d.m.) and sandstone (2/3 d.m.). The compost made from a mixture of digested sludge and sawdust was provided by the Sieg-Roche (Canton de Vaud, Switzerland) pilot plant after 9 months of maturation (Hubert 1985) and was mixed with a Permian sandstone without calcium carbonate from the Vosges massif (France).

APPLICATION OF TEST SUBSTANCE TO SOIL
- Method: Test substance was dissolved in ethanol at 0.4 mL/g spiked compost. The dissolved substances were mixed with part of the compost (4g d.m.) nd the ethanol was left to evaporate. The spiked compost was then mixed thoroughly in an incubation cell with the rest of the 60g sample (16g d.m. compost + 40g d.m. sandstone).

VEHICLE:
- Chemical name of vehicle: Ethanol
- Evaporation of vehicle before use: Yes

Test organisms (inoculum):

other: aged mixture of sewage sludge compost and sandstone

Total exposure duration:

40 d

Test temperature:

25 °C

Moisture:

60% water-holding capacity

Details on test conditions:

TEST SYSTEM
- Test container (type, material, size): Incubation cell in a multipurpose assembly incubator ( with intermittent aeration)
- No. of replicates per concentration: 1 (triplicates were mixed on removal from test cells)
- No. of replicates per vehicle control: 1 (triplicates were mixed on removal from test cells)
- Other: Incubated in darkness.

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographical reference of sampling site (latitude, longitude): Reconstituted soil was used comprising a mixture of mature sewage sludge compost (1/3 d.m.) and sandstone (2/3 d.m.). The compost made from a mixture of digested sludge and sawdust was provided by the Sieg-Roche (Canton de Vaud, Switzerland) pilot plant after 9 months of maturation and was mixed with a Permian sandstone without calcium carbonate from the Vosges massif (France).
- Soil texture of the sandstone
- % sand: 75%
- % silt: 12%
- % clay: 13%
- pH (in water): 6.80 (mixed soil)
- C:N ratio: 20 (mixed soil)
Total P: 1% (mixed soil)
- Maximum water holding capacity (in % dry weight): 51% WHC of mixed soil and adjusted to 60% WHC for the test
- Cation exchange capacity (mmol/kg): 22.1 meq/100g of the mixed soil

EFFECT PARAMETERS MEASURED: Respiration (CO2 evolution) was recorded daily throughout the test period of 40 days. The cells were flushed periodically with a stream of CO2-free air to remove accumulated CO2 and restore the O2 content, the effluent air being bubbled in 15 mL 0.1 N NaOH. The absorbed CO2 was determined by a conductivity method.

VEHICLE CONTROL PERFORMED: yes

Nominal and measured concentrations:

Nominal: 100 and 1000 ppm

Reference substance (positive control):

no

Key result

Duration:

40 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

respiration rate

Details on results:

Respiration started at the same rate (37 µg C/g organic C per h) in control and treatments. The rates then decreased progressively, indicating depletion of easily mineralizable C and N. CO2 evolution did not differ significantly between the 100 ppm samples and the controls. In contrast, in 1000 ppm samples, CO2 evolution was significantly depressed by the 4th day (F< 0.05). Respiration was depressed by an average o f 64% compared with controls between the 5th and the 40th days.

Validity criteria fulfilled:

yes

Conclusions:

In a long-term toxicity test performed similar to OECD guideline 217, a 40d-NOEC value of 100 mg/kg dw was measured for inhibition of microbial respiration of a mixture of sewage sludge compost and sandstone.

Executive summary:

In a long-term toxicity test performed similar to OECD guideline 217, soil microbes were incubated with 100 and 1000 ppm branched 4-nonylphenol (NP) over an exposure time of 40 days. An aged mixture of sewage sludge compost and sandstone was used as inoculum. Respiration (CO2 evolution) was recorded daily throughout the test period. Respiration started at the same rate (37 µg C/g organic C per h) in control and treatments. The rates then decreased progressively, indicating depletion of easily mineralizable C and N. CO2 evolution did not differ significantly between the 100 ppm samples and the controls. In contrast, in 1000 ppm samples, CO2 evolution was significantly depressed by the 4th day. Thus, the 40d-NOEC value is determined to be 100 mg/kg dw.

Reference 2

Endpoint:

toxicity to soil microorganisms

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Analogue justification attached (chapter 13).

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

40 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

respiration rate

Description of key information

NOEC (40d) = 100 mg/kg (nominal) for respiration inhibition of mixture of sewage sludge compost and sandstone (read across)

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

100 mg/kg soil dw

Additional information

Since no study assessing the toxicity of Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (CAS 174333-80-3) to soil microorganisms is available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across to Phenol, 4-nonyl-,branched was conducted, which is a secondary component and structurally similar to the main component of the substance. The only structural difference between the source substance and the target substance is the lack of an aldoxime group at the phenol ring of the molecule.

The read across is justified due to the following reasons:

1) The similarity of structure and functional groups and accordingly similar physico-chemical properties result in similar environmental behavior and fate.

2) Based on a profound ecotoxicological data set available for Phenol, 4-nonyl-,branched it can be concluded that Phenol, 4-nonyl-,branched exhibit an equal to higher aquatic toxicity compared to Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (see table below). Therefore, using data from Phenol, 4-nonyl-,branched to assess the intrinsic hazard of Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched is considered to be a very conservative approach (worst case scenario).

Substance	Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched	Phenol, 4-nonyl, branched^*
CAS number	174333-80-3	84852-15-3
Structure	see attachment (chapter 6.3)	see attachment (chapter 6.3)
Molecular formula	C16O2NH25	C15H24O
Molecular weight	~ 263 g/mole	~ 220.35 g/mole
PC parameter
Water solubility	0.4 mg/L (EU method A.6)	5.7 mg/L (ASTM E 1148-02)
Partition coefficient	5.5 (EU method A.8)	5.4 (OECD 117)
Vapour pressure	0.37 Pa at 20 °C (OECD 104)	~1 Pa at 20 °C (ASTM-D 2879)
Environmental fate
Biodegradability	0 % in 28 days (OECD 302c)	non-adapted inoculum: 0 % in 28 days (OECD 301B)   adapted inoculum: 48.2-62 % in 28 days (OECD 301B)
Adsorption [log KOC]	3.7 (OECD 121)	4.35 - 5.69 (EPA OTS 796.2750)
Hydrolysis	not relevant
Ecotoxicology
Short-term toxicity to fish [96h-LC50]	1.1 mg/L (EU method C.1)	0.05 – 0.22 mg/L (different methods)
Long-term toxicity to aquatic invertebrates [NOEC]	0.005 mg/L (OECD 210)	0.006 mg/L (ASTM E 1241-05)
Short-term toxicity to aquatic invertebrates [48h-EC50]	2.7 mg/L (EU method C.2)	0.08 – 0.14 mg/L (different methods)
Long-term toxicity to aquatic invertebrates [21d-NOEC]	0.189 mg/L (OECD 211)	0.024 - 0.116 mg/L (different methods)
Short-term toxicity to algae [72h-EC50]	36.3 mg/L (OECD 201)	0.33 - 1.3 mg/L (different methods)
Long-term toxicity to algae [72h-NOEC/EC10]	14.9 mg/L (OECD 201)	0.5 mg/L (Algal growth inhibition test according to UBA 1984)
Toxicity to microorganisms [EC50]	200.4 mg/L (OECD 209)	950 mg/L (OECD 209)

* Data were taken from Phenol, 4-nonyl-,branched (CAS 84852-15-3) dossier published on the ECHA data base

 

In a long-term toxicity test performed similar to OECD guideline 217, soil microbes were incubated with 100 and 1000 ppm branched 4-nonylphenol (NP) over an exposure time of 40 days (Trocme et al. 1988). An aged mixture of sewage sludge compost and sandstone was used as inoculum. Respiration (CO2 evolution) was recorded daily throughout the test period. Respiration started at the same rate (37 µg C/g organic C per h) in control and treatments. The rates then decreased progressively, indicating depletion of easily mineralizable C and N. CO2 evolution did not differ significantly between the 100 ppm samples and the controls. In contrast, in 1000 ppm samples, CO2 evolution was significantly depressed by the 4th day. Thus, the 40d-NOEC value is determined to be 100 mg/kg dw. Based on the reasons given above this value is considered to be sufficiently conservative to be used for the hazard assessment of Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (CAS 174333-80-3).