Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01820-0015-0000-9
Chemical Name:	Calcium chromate
CASRN:	13765-19-0
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	G74975
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	Dimethyl Sulfoxide	0	96	116	106	37	42
Vehicle Control			79	84	112	47	42
Test Chemical	Calcium chromate	0.16	88	78	189	72	81*
			56	58	152	90	81*
		0.31	80	69	147	62	70*
			90	78	213	79	70*
		0.63	69	51	238	114	120*
			72	57	272	126	120*
		1.25	54	27	340	211
		2.5	52	17	405	258
		5	23	5	425	612	638*
			23	5	449	665	638*
Positive Control	Ethyl Methane Sulfonate	500	39	24	690	590	557*
Positive Control			47	33	738	523	557*

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	84	89	130	51	48
Vehicle Control			75	111	98	44	48
Test Chemical	Calcium chromate	0.16	47	68	81	57	62
			73	112	146	67	62
		0.31	52	83	107	69	71
			50	61	110	73	71
		0.63	42	51	164	129	112*
			48	49	134	94	112*
		1.25	41	33	181	148	172*
			34	31	201	196	172*
		2.5	32	17	259	267	247*
			28	14	188	228	247*
		5	22	9	250	385	501*
			13	4	244	618	501*
Positive Control	Ethyl Methane Sulfonate	500	11	8	560	1723	1204*
Positive Control			28	19	576	686	1204*

Non-Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	65	87	299	155	115
Vehicle Control			65	113	145	75	115
Test Chemical	Calcium chromate	8.4	67	126	247	123	128
			58	96	228	132	128
		12	49	70	277	188
		17.2	62	81	419	227	191*
			53	75	247	154	191*
		24.5	60	77	350	193	249*
			42	49	386	304	249*
		35	29	17	297	347	349*
			35	23	369	351	349*
		50

Positive Control	3-Methylcholanthrene	5	44	53	408	308	308*
	3-Methylcholanthrene	100	3r	2	98	1307
			7r	5	105	525

Non-Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	86	98	140	54	56
Vehicle Control			84	102	147	58	56
Test Chemical	Calcium chromate	1.56	83	110	142	57	63
			79	107	163	69	63
		3.13	86	100	187	73	74
			89	112	203	76	74
		6.25	73	92	190	86	88
			83	116	226	91	88
		12.5	62	77	389	210	187*
			77	72	378	164	187*
		25	49	38	501	344	341*
			46	39	465	337	341*
		50	15	5	445	989
Positive Control	3-Methylcholanthrene	7	45	44	401	297	254*
Positive Control			68	47	433	211	254*

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	93	113	100	36	44
Vehicle Control			95	87	151	53	44
Test Chemical	Calcium chromate	5.9	79	67	219	92	94*
			58	56	166	96	94*
		8.4	69	65	259	126	129*
			86	72	341	132	129*
		12	76	65	344	150	146*
			72	57	302	141	146*
		17.2	71	51	384	179	183*
			58	38	326	187	183*
		24.5	57	34	447	261	279*
			44	24	392	297	279*
		35	27	7	373	455	451*
			31	11	420	447	451*
		50

Positive Control	3-Methylcholanthrene	5	75	76	414	184	197*
			69	69	434	211	197*
	3-Methylcholanthrene	100	6r	3	103	624
			9r	6	129	487

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	104	111	110	35	39
Vehicle Control			83	89	104	42	39
Test Chemical	Calcium chromate	8.4	87	80	216	83	73*
			74	62	140	63	73*
		12	70	51	219	104	103*
			69	44	213	102	103*
		17.2	57	37	223	130	128*
			57	34	215	126	128*
		24.5	44	20	197	149	141*
			41	19	161	133	141*
		35	19	3	111	200
		50

Positive Control	3-Methylcholanthrene	6	26	15	230	301	321*
Positive Control			25	14	252	341	321*

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