Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01046-0013-0000-7
Chemical Name:	1,2-Dichlorobenzene (o-dichlorobenzene)
CASRN:	95-50-1
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	881718
Study Result:	Positive

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Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 1 Experiment Call: Inconclusive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	104	90	72	23	29
			124r	105	96	26
			95	103	87	30
			93	107	91	33
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	2	100	89	63	21	23
			91	74	62	23
			88	75	63	24
		3	87	78	62	24	22
			93	94	62	22
			107	88	59	18
		4	77	81	69	30	25
			84	75	69	27
			95	75	52	18
		5	111	95	79	24	27
			108	91	101	31
			122r	87	83	23
		6	115	78	78	23
			124r	100	93	25
			152r	123	94	21
		8	99	77	93	31	27
			91	71	72	27
			99	71	73	25
Positive Control	Methyl Methane Sulfonate	5	74	73	351	158	146*
Positive Control			91	80	367	134	146*

Nonactivation Trial: 2 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	104	104	43	14	19
			109	107	70	21
			96	89	73	25
			104	100	53	17
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	2.5	87	84	60	23	22
			69	88	48	23
			74	83	44	20
		5	67	68	44	22	21
			78	77	47	20
			94	102	59	21
		7.5	84	79	61	24	20
			91	85	55	20
			97	85	50	17
		10	118	88	66	19	20
			117	111	61	17
			91	89	68	25
		15	123r	113	71	19
			164r	126	55	11
			118	108	60	17
		20	129r	94	94	24
			105	72	47	15
			123r	102	74	20
Positive Control	Methyl Methane Sulfonate	5	58	43	409	234	218*
			86	65	485	188
			65	41	451	232

Nonactivation Trial: 3 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	82	101	60	24	24
			97#	130	57	20
			73#	69	64	29
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	2.5	86	66	35	14	18
			77	88	54	23	18
		5	67	66	39	19	19
			73	80	40	18	19
		10	65	59	42	21	19
			89	66	45	17	19
		20	80#	73	51	21	21
			84	63	36	14
			64	78	53	27
		30	74#	31	58	26	20
			61	30	33	18
			87	33	44	17
Positive Control	Methyl Methane Sulfonate	5	84	97	531	210	205*
Positive Control			82#	88	489	199	205*

Nonactivation Trial: 4 Experiment Call:
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	89	92	107	40	46
			107	100	145	45
			93	90	142	51
			79	118	112	47
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	20	102	98	107	35	41
			93	74	125	45
			94	85	120	42
		30	75	72	88	39	38
			85	90	90	35
			91#	70	107	39
		40	113	75	205	61	53
			115	174	140	41
			93	69	159	57
		50	107	57	143	45
			132r	70	161	41
			137r	78	179	43
		60	110	66	155	47	43
			100	57	148	49
			114	78	114	33
		80					84*
			76	39	198	87
			87	19	209	80
		100


Positive Control	Methyl Methane Sulfonate	5	77	63	581	250	233*
			69	55	393	190
			75	82	582	258

Nonactivation Trial: 5 Experiment Call:
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	78#	92	62	27	29
			91	84	80	29
			91	94	91	33
			99	130	82	28
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	30	89	62	98	37	40
			86	58	89	34
			79	68	118	50
		40	84	78	71	28	24
			83	67	59	24
			113	54	70	21
		50	68	45	70	34	33
			61	42	59	32
			91	62	89	33
		60	73	38	93	43	31
			67	44	59	29
			91	44	57	21
		80	113	18	80	24	27
			88	66	90	34
			119	36	79	22
		100	85	6	140	55	40
			94	10	97	34
			91	6	81	30
Positive Control	Methyl Methane Sulfonate	5	74	41	376	169	195*
			75#	50	514	228
			66	40	373	188

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	62	87	98	53	63
			62	112	148	80
			70	138	102	49
			75	64	156	69
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	5	60	78	186	103	127*
			44	75	170	129
			17	25	75	149
		10	39	55	200	170	166*
			33	38	179	182
			46	75	204	147
		20	45	30	302	222	420*
			15	15	288	647
			39	29	453	391
		30	38#	17	358	315	213*
			34	22	229	223
			48	38	146	101
		40	53	18	468	293	346*
			34	10	410	398	346*
		60	38	11	391	343	379*
			42	14	477	380
			31	13	381	414
Positive Control	3-Methylcholanthrene	2.5					335*
			52	45	634	406
			63	46	499	263

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	82	100	160	65	67
			87	104	179	68
			87	104	146	56
			86	92	200	77
Test Chemical	1,2-Dichlorobenzene (o-dichlorobenzene)	5	65	76	290	149	159*
			64	102	364	189
			79	64	326	138
		10	71	62	333	157	171*
			64	57	378	196
			78	72	373	159
		20	78	43	573	244	249*
			67	45	534	267
			80	50	565	237
		30	50	8	745	497	404*
			63	24	680	363
			53	23	564	354
		40	39	13	616	533	501*
			47	15	658	468	501*
		60


Positive Control	3-Methylcholanthrene	2.5	62	48	682	366	305*
			41#	55	385	314
			57	62	404	236

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination