diuron (ISO); 3-(3,4-dichlorophenyl)-1,1-dimethylurea

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Mar 1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Diuron

EC Number:

206-354-4

EC Name:

Diuron

Cas Number:

330-54-1

Molecular formula:

C9H10Cl2N2O

IUPAC Name:

3-(3,4-dichlorophenyl)-1,1-dimethylurea

Details on test material:

- Physical state: solid
- Analytical purity: 98.8%
- Lot/batch No.: 232114080
- Stability under test conditions: yes

Method

Target gene:

not applicable

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

S9-mix (induced with Aroclor 1254) from rats

Test concentrations with justification for top dose:

0, 125, 250, 500, 1000, 2000 µg/plate per strain

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Cyclophosphamide, Trypaflavine and 2-Aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- no Preincubation period
- Exposure duration: 48 h at 37 °C

NUMBER OF CELLS EVALUATED:
minimal culture density: approx. 0.1 x 10 to the power 7 CFU/mL;
approx. maximum: 4 x 10 to the power of 9 CFU/mL

DETERMINATION OF CYTOTOXICITY
performed between 0 to 12500 µg/plate

OTHER: 4 plates per strain and dose, both with and without metabolic activation; same number of vehicle controls;

Evaluation criteria:

A reproducible, dose-related increase in the mutant counts of at least one strain is considered positive , and about double the negative control should be reached

Statistics:

The ANOVA model was used for calculations

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

For strains TA 98, 1535 and 1537 cytotoxicity was observed at 500 µg/plate and above with and without metabolic activation. For strain TA 100 cytotoxicity was revealed at 2500 µg/plate and above with and without metabolic activation

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
The two highest dose levels (1000 and 2000 µg/plate) were toxic as evidenced by thinning bacterial lawn and/or reduced revertant count

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Results of cytotoxicity testing (mean of 4 countings)

	Without S9-mix				With S9-mix
µg/plate	TA100	TA1535	TA98	TA1537	TA100	TA1535	TA98	TA1537
0	100	28	18	6	135	17	33	6
20	100	35	20	5	127	8	35	8
100	80	29	19	4	107	15	29	7
500	62	B	B	B	123	12	24	5
2500	B	B	B	0	37	B	B	B
12500	P	P	P	P	P	P	P	P
2-AA 3 µg	138	20	40	12	1284	344	669	92
Endoxan 145 µg	n.p.	32	n.p.	n.p.	n.p.	458	n.p.	n.p.
Endoxan 290 µg	96	n.p.	n.p.	n.p.	621	n.p.	n.p.	n.p.
Trypaflav. 50 µg	n.p.	n.p.	87	64	n.p.	n.p.	2895	971

B - background growth

P - precipitation

n.p. - not performed

Table 2: Results of mutagenicity testing (mean of 4 countings)

Strain TA 1535
µg / Plate	Mutants / Plate		Bact./ml
	- S 9	+ S 9	Exp. +8
0	30±4	14±2	42.2
125	33±5	11±4	41.4
250	20±2	13±3	34.9
500	b**	9±3	38.3
1000	0±0	5±2	6.0 **
2000	0±0	b	0.9 **
Endoxan, 145µg	31±7	205±9	40.7
2-AA, 3 µg	31±6	231±28	37.8
Strain TA 100
0	110±11	132±13		35.4
125	103±15	106±9		28.6
250	90±10	132±11		9.3**
500	41±6	91±21		7.2**
1000	b	70±17		0.9 **
2000	b	25 p±8		0.3 **
Endoxan, 290µg	130±11	398±36		37.4
2-AA, 3 µg	133±18	1017±166		35.2
Strain TA 1537
0	8±3	9±1	32.7
125	3±1	9±3	30.7
250	b	7±1	18.6**
500	3±3	4±2	2.5**
1000	0±0	2±2	0.1 **
2000	0±0	3 p±2	< 0.1 **
T.flavin, 50µg	54±14	336±33	28.3
2-AA, 3 µg	11±3	74±5	34.4
Strain TA 98
0	27±5	26±6	34.8
125	17±3	31±2	31.8
250	9±5	31±7	9.1**
500	b	24±6	2.3**
1000	0±0	25±6	0.2**
2000	0±0	9 p±5	0.2**
T.flavin, 50µg	51±15	816±51	31.4
2-AA, 3µg	43±7	316±50	40.7

**- background

b - bactericidal effect

p - precipitation

The two highest dose levels (1000 and 2000 µg/plate) were toxic as evidenced by thinning bacterial lawn and/or reduced revertant count. Diuron did not increase the number of revertant colonies at any exposure level, with or without activation .No dose-related increase in mutant colonies was observed. The sensitivity of the test system was evidenced by concurrent positive controls.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Executive summary:

A reliable genetic toxicity in vitro study was performed according to Ames (1975).Diuron was applied in concentrations of 0, 125, 250, 500, 1000, and 2000 µg/plate. Diuron was not mutagenic in the four tested Salmonella strains up to toxic concentrations both in the presence and absence of a rat metabolic activation system under the conditions employed. (Herbold 1984)