Frequency of eating fish and seafood	n	Med (SD)
Frequency of eating fish and seafood	n	Hair, mkg/g	umbilical blood, mkg/l	Urine, mkg/l
12 times in a week	21	0.30 (0.15)	1.18 (0.75)	0.43 (0.47)
12 times in a week		t = 3.11, p < 0.01	t = 2.69, p < 0.01	t = 3.18, p < 0.01
2 - 3 times a month	64	0.19 (0.13)	0.79 (0.54)	0.25 (0.20)
Less often	34	0.15(0.13)	0.71 (0.7)	0.25 (0.17)