Toxicities of phenols to Tetrahymena pyriformis^a.

Compound	−log IGC50 (mmol L−1)	Compound	−log IGC50 (mmol L−1)
Phenol	−0.431	2-Isopropylphenol	0.803
*p-Cresol	−0.192	*3-Chloro-4-fluorophenol	0.842
m-Cresol	−0.062	4-Iodophenol	0.854
2,5-Dimethylphenol	0.009	4-tert-Butylphenol	0.913
3-Fluorophenol	0.017	2,3,7-Trimethylphenol	0.93
3,5-Dimethylphenol	0.113	2,4-Dichlorophenol	1.036
*2,3-XYLENOL	0.122	*2-Phenylphenol	1.094
3,4-Dimethylphenol	0.122	3-Iodophenol	1.118
2,4-Dimethylphenol	0.128	2,5-Dichlorophenol	1.128
2-Ethylphenol	0.176	4-Chloro- 3,5-dimethylphenol	1.203
2-Fluorophenol	0.248	2-(tert-Butyl)-4,6-dimethylphenol	1.245
*2-Chlorophenol	0.277	*2,3-Dichlorophenol	1.271
3-Ethylphenol	0.299	4-Bromo-6-chloro-2-methylphenol	1.277
2,6-Dichlorophenol	0.396	4-Bromo-2,6-dimethylphenol	1.278
3,4,5-Trimethylphenol	0.418	2-tert-Butyl-4-methylphenol	1.297
4-Fluorophenol	0.473	2,4-Dibromophenol	1.403
*4-Isopropylphenol	0.473	*3,5-Dichlorophenol	1.562
2-Bromophenol	0.504	2,4,6-Trichlorophenol	1.695
4-Chlorophenol	0.545	4-Bromo-2,6-dichlorophenol	1.779
3-Isopropylphenol	0.609	2,6-Di-tert-Butyl-4-methylphenol	1.788
2-Chloro- 5-methylphenol	0.64	4-Chloro-2-isopropyl-5-methylphenol	1.862
*4-Bromophenol	0.681	*2,4,6-Tribromophenol	2.05
4-Chloro-2-methylphenol	0.7	2,4,5-Trichlorophenol	2.1
3-tert-Butylphenol	0.73	2,6-Diphenylphenol	2.113
4-Chloro-3-methylphenol	0.795	2,4-Dibromo-6-phenylphenol	2.207

^a−log IGC₅₀: half-maximal growth inhibitory concentration. *A test set sample.