Amines, C12-18-alkyldimethyl

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial plants: short-term (with study design considered suitable for long-term assessment)

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

For details on endpoint-specific justification, please see read-across justification document (category approach) in the linked category of dimethylalkylamines.

Analytical monitoring:

no

Vehicle:

yes

Species:

other: Gramineae

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Avena sativa (oat)2, Flämingstern

Species:

other: Brassicaceae

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Brassica napus (rape)2, Petronova

Species:

other: Leguminosae

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Trifolium pratense (red clover)1, Viola

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

other: Natural soil: Certified LUFA soil No. 2.3 (batch-no. Sp2.35000)

Limit test:

no

Total exposure duration:

21 d

Post exposure observation period:

No

Test temperature:

20±10

pH:

6.5±0.2

Moisture:

See "Any other information on materials and methods inc. tables"!

Nominal and measured concentrations:

Nominal concentrations:
Conc. (mg/kg dry weight soil) : 10, 32, 100, 320, 1000
No analytical determination preformed!

Reference substance (positive control):

yes

Remarks:

8 replicates applied with 28.6 g lyophilised sewage sludge and 160 g quarts sand

Key result

Species:

Brassica napus

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

11.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

other: RA from C12-14-DMA; value converted based on MW

Basis for effect:

other: Shoot height

Remarks on result:

other: Orig. value source: 10 mg/kg dw

Details on results:

See tables below!

Results with reference substance (positive control):

No reference substance

Reported statistics and error estimates:

NOEC of biomass/ emerged seedlings:
The NOEC was determined for inhibition of shoot height, inhibition of fresh weight and the rate of emergence. Dead plants were measured, weighed and observed and included in the statistical analysis if possible.
One way analysis of variance (ANOVA) and DUNNETT'S test was carried out for the determination of statistically significant differences compared to control replicates. When running a one way analysis of variance a normality test and an equal variance test were done first. P-values for both normality and equal variance test are 0.05. The a-value for ANOVA (acceptable probability of incorrectly concluding that there is a difference) is a = 0.05.

EC-values and confidence ranges of growth:
Calculation was carried out via probit analysis. Probit values according to WEBER (1986). Calculation of the confidence intervals for EC 50 were carried out using standard procedures according to BREITIG & TÜMPLING (1982).

BREITIG & TÜMPLING (1982): Methoden der Wasseruntersuchungen Bd.11., VEB GUSTAV FISCHER VERLAG, Jena.
WEBER, E., Grundrifl der biologischen Statistik. 9. Auflage (1986).

shoot height

Species	NOEC* (mg/kg DW)	EC25 (mg/kg DW)	p= 95% (mg/kg DW)	EC50(mg/kg DW)	p=95% (mg/kg DW)
oat	320	526	360-769	>1000	823- >1000
rape	10	52	38-71	120	88-165
red clover	32	114	101-130	159	141-180

fresh weight

Species	NOEC* (mg/kg DW)	EC25 (mg/kg DW)	p= 95% (mg/kg DW)	EC50(mg/kg DW)	p=95% (mg/kg DW)
oat	100	473	408-548	700	604-811
rape	100	53	40-70	127	96-169
red clover	32	129	112-149	188	164-217

seed emergence

Species	NOEC* (mg/kg DW)	EC25 (mg/kg DW)	p= 95% (mg/kg DW)	EC50(mg/kg DW)	p=95% (mg/kg DW)
oat	320	671	555-812	>1000	-
rape	320	402	338-478	586	493-697
red clover	320	101	77-133	237	180-313

- not determinable

* the highest tested concentration of the test item at which no statiscally significant effect is observed

Phytotoxic effect: decrease in lenght
Species	NOEC* (mg/kg DW)	EC25 (mg/kg DW)	p= 95% (mg/kg DW)	EC50(mg/kg DW)	p=95% (mg/kg DW)
oat	320	>1000	-	>1000	-
rape	100	233	214-254	281	258-306
red clover	n.o	n.o	-	n.o	-

Phytotoxic effect: deformation
Species	NOEC* (mg/kg DW)	EC25 (mg/kg DW)	p= 95% (mg/kg DW)	EC50(mg/kg DW)	p=95% (mg/kg DW)
oat	320	>1000	-	>1000	-
rape	n.o	n.o	-	n.o	-
red clover	n.o	n.o	-	n.o	-

Phytotoxic effect: chlorosis
Species	NOEC* (mg/kg DW)	EC25 (mg/kg DW)	p= 95% (mg/kg DW)	EC50(mg/kg DW)	p=95% (mg/kg DW)
oat	n.o	n.o	-	n.o	-
rape	100	275	164-460	844	504- >1000
red clover	n.o	n.o	-	n.o	-

n.o: not observed (effects < 10% were not considered)

- not determinable

* The higutest tested dose of the test item at which no statistically significant effect is observed

Validity criteria fulfilled:

no

Remarks:

For red clover less than 70% seedling ermgence for control (55%). This criterion was not yet established in the draft guideline version.

Executive summary:

The study used as source investigated the effects of C12-14-DMA towards terr. plants in a Seedling Emergence and Seedling Growth test (OECD 208). The study results of the source substance were considered applicable to the target substance. Justification and applicability of the read-across approach (category approach) is outlined in the read-across report in the linked category of dimethylalkylamines.

Description of key information

In a reliable study (reliability category 2) on C12-14 DMA assessing toxicity in regard to seedling emergence, phytotoxic effects, shoot height and shoot fresh weight for three plant species, the most sensitive endpoint was shoot height for rape: NOEC (21 d) = 0.045 mmol/kg soil dry weight.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:

8.41 mg/kg soil dw

Additional information

Toxicity of C12-14 DMA in regard to seedling emergence, phytotoxic effects, shoot height and shoot fresh weight of terrestrial plants was assessed in a reliable (category 2) seedling emergence test over a period of 21 days (OECD 208, compliant to GLP) at nominal concentrations of 10 -32 -100 -320 -1000 mg/kg soil dry weight (DW). Tested plant species were the monocotyledon oats (Gramineae) and the two dicotyledons rape (Brassicaceae) and red clover (Leguminosae). Validity criteria of the OECD-guideline were met, except for control seedling emergence of red clover (<70%; reason for RL 2 – no other restrictions regarding reliability). The following NOECs (21 d) were determined:

Shoot height: oat 320 mg/kg DW; rape 10 mg/kg DW; red clover 32 mg/kg DW

Fresh weight: oat 100 mg/kg DW; rape 100 mg/kg DW; red clover 32 mg/kg DW.

Phytotoxic effects: oat (decrease in length) 320 mg/kg DW; rape (decrease in length) 100 mg/kg DW; rape (chlorosis) 100 mg/kg DW

Thus, the lowest NOEC (21 d) of 0.045 mmol/kg soil dry weight (10 mg C12-14-DMA)/kg dry weight was determined for shoot height of rape, and this NOEC will be the decisive value for PNECsoil derivation for DMA category members due to plants being more sensitive to DMA than soil microorganisms or terrestrial macroorganisms.
However, molar concentrations cannot be used for environmental hazard and risk assessment. Therefore, in a conservative way the molecular weight of C10-DMA is used to transform the molar into mass-based concentration:
Key value for terrestrial plant toxicity of DMA category members: NOEC (21 d; Brassica napus; shoot height) = 8.41 mg/kg soil dry weight.