Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01820-0013-0000-7
Chemical Name:	Calcium chromate
CASRN:	13765-19-0
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	186899
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: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	30r	53	60	67	61
			60	101	122	68
			19r	34	12	21
			72	99	116	53
Test Chemical	Calcium chromate	1.25	84	98	181	72	63
			80	120	130	55	63
		2.5	65	89	163	83	83
			88	73	216	82	83
		5	62	57	290	155	156*
			61	45	284	156	156*
		10	38	25	380	335	351*
			36	17	399	368	351*
		20
			15	3	185	407
		40

Positive Control	Ethyl Methane Sulfonate	200	85	78	547	216	208*
Positive Control			72	73	433	201	208*

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	61	92	49	27	30
			71	102	79	37
			63	97	52	28
			73	109	58	27
Test Chemical	Calcium chromate	1.25	70	84	156	74	70*
			64	61	128	66	70*
		2.5	50	53	144	96	95*
			58	55	163	94	95*
		5	33	13	222	222	183*
			43	22	184	144	183*
		10

Positive Control	Ethyl Methane Sulfonate	250	77	86	269	116	116*
Positive Control			59	56	205	115	116*

Nonactivation Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	90	107	161	60	71
			83	103	204	82
			69	90	153	74
			83	100	171	69
Test Chemical	Calcium chromate	1.25	64	98	213	112	120*
			64	76	248	129	120*
		2.5	81	102	308	126	148*
			70	70	352	169	148*
		5	59	49	436	248	258*
			55	48	441	269	258*
		10	43	14	803	630	654*
			34	15	692	678	654*
		20

Positive Control	Ethyl Methane Sulfonate	250	76	76	725	317	316*
Positive Control			58	69	546	316	316*

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	58	79	158	91	78
			59	99	172	97
			91	106	145	53
			86#	116	184.5	72
Test Chemical	Calcium chromate	2.5	68#	106	201	99	78
			96#	126	162	56	78
		5	80	97	267	112	97
			89	105	217	82	97
		10	65	78	383	196	160*
			84	86	313	125	160*
		20	52	41	578	368	331*
			69	46	610	293	331*
		40	24	4	760	1070	1043*
			18#	4	553.5	1016	1043*
Positive Control	3-Methylcholanthrene	2.5	64	125	166	87	67
Positive Control			95	136	135	47	67

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	68#	120	165	81	95
			66	101	131	66
			54	77	192	119
			66	103	225	113
Test Chemical	Calcium chromate	1.25	93	93	298	107	105
			84	96	259	103	105
		2.5	68#	83	297	146	166*
			68	80	380	186	166*
		5	59	54	761	430	387*
			53	41	543	344	387*
		10	27	4	778	960	1000*
			29	7	894	1040	1000*
		20

Positive Control	3-Methylcholanthrene	2.5	31	9	550	585	561*
Positive Control			30#	7	477	536	561*

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