Table 2.

Mutagenicity of extract from PM samples collected at six ceramic factories (A–F)

Treatment	Revertant colony of TA 100 per plate (n=6)
	A	B	C	D	E	F
DMSO (negative control)	14±3	32±4	32±2	33±3	33±4	23±3
AF-2 (positive control)	232±13	392±10	392±11	263±9	263±10	212±12
PM extract 10 μg	18±6	43±8	33±7	32±4	29±6	21±5
PM extract 100 μg	23±4	42±10	35±6	39±7	31±3	14±4
PM extract 350 μg	14±5	33±9	30±5	18±8	22±5	39±3

AF-2: 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide