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Study Information
Study Attribute Value
CEBS Accession Number: 002-02063-0012-0000-6
Chemical Name: Dimethyl methylphosphonate
CASRN: 756-79-6
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 369588
Study Result: Positive


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.
uL/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 79 114 91 39 43
    72 100 82 38
    56 88 85 51
    63 98 86 45
Test Chemical Dimethyl methylphosphonate 
 0.25      
 82 128 67 27 36
    68 112 68 34
    36 80 52 48
  
 0.5       
 64 98 92 48 49
    67 87 105 52
    60 78 86 48
  
1         
 48 52 99 69 58
    88 79 129 49
    58 96 98 56
  
1.5       
 93 81 199 71 76*
    60# 51 122 68
    58 51 152 87
  
3         
 75 73 188 83 83*
    86 90 192 75
    63 65 175 92
  
5         
 73 70 240 110 90*
    89 80 199 74
    74 57 190 85
Positive Control Methyl Methane Sulfonate 
5         
 58 58 590 336 387*
    71 30 640 303
    35 22 546 522

Nonactivation Trial: 2 Experiment Call: Positive
  Conc.
uL/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 103 132 53 17 23
    72 86 70 32
    86 90 58 23
    82 93 54 22
Test Chemical Dimethyl methylphosphonate 
 0.25      
 61# 70 112 61 40*
    83 95 76 31
    85# 84 75 30
  
 0.5       
 79 76 97 41 49*
    39 59 59 50
    57# 86 94 55
  
1         
 56 62 101 61 50*
    62# 83 74 40
  
2         
 62# 72 95 51 53*
    63# 61 109 58
    75# 69 111 50
  
3         
 70# 73 142 68 63*
    51 51 79 51
    62 63 129 69
  
5         
 80 53 210 87 77*
    93 44 186 67
Positive Control Methyl Methane Sulfonate 
5         
 64 53 288 151 145*
    70# 54 299 142
    84 44 359 143

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