Individual exposures to drinking water trihalomethanes, low birth weight and small for gestational age risk: a prospective Kaunas cohort study

Table 1 THM levels (μg/L) by sampling site, water supply zone, year and season of sampling

Tap water sampling	TTHMs^cMean (SD^d)	CHCl₃Mean (SD)	CHBr₂Cl Mean (SD)	CHBrCl₂Mean (SD)
Sampling sites
All sites	9.8 (12.4)	7.8 (10.2)	0.3 (0.5)	1.7 (2.2)
Low THM level^a	1.3 (1.2)	0.9 (1.0)	0.1 (0.2)	0.3 (0.5)
High THM level^b	21.9 (10.9)	17.7 (9.0)	0.5 (0.6)	3.6 (2.1)
Year of sampling
2007 all sites	10.3 (13.5)	8.7 (12.0)	0 (0 ^e)	1.5 (1.6)
Low THM level^a	0.9 (1.3)	0.39 (1.0)	0 (0)	0.6 (0.5)
High THM level^b	24.2 (11.0)	21.3 (9.6)	0 (0)	2.9 (1.7)
2008 all sites	6.2 (10.2)	4.4 (7.5)	0.3 (0.5)	1.5 (2.4)
Low THM level^a	1.5 (1.1)	0.9 (0.6)	0.2 (0.3)	0.5 (0.5)
High THM level^b	12.7 (13.5)	9.3 (9.8)	0.6 (0.6)	2.8 (3.3)
2009 all sites	11.8 (12.8)	9.5 (10.0)	0.4 (0.5)	1.9 (2.3)
Low THM level^a	1.3 (1.1)	1.3 (1.0)	0.1 (0.2)	0.1 (0.2)
High THM level^b	26.5 (2.9)	21.0 (2.3)	0.9 (0.4)	4.6 (0.5)
Season of sampling
Spring all sites	8.5 (12.1)	6.8 (9.7)	0.3 (0.4)	1.4 (2.1)
Low THM level^a	1.4 (1.3)	1.2 (1.1)	0.1 (0.3)	0.2 (0.4)
High THM level^b	18.3 (13.6)	14.7 (10.9)	0.5 (0.5)	3.1 (2.3)
Summer all sites	9.9 (12.7)	8.3 (11.3)	0 (0)	1.6 (1.7)
Low THM level^a	1.0 (1.4)	0.4 (1.0)	0 (0)	0.7 (0.5)
High THM level^b	24.1 (8.3)	21.0 (7.0)	0 (0)	3.1 (2.0)
Autumn all sites	11.1 (13.4)	8.8 (11.1)	0.2 (0.5)	2.0 (2.4)
Low THM level^a	1.2 (1.1)	0.8 (0.9)	0 (0)	0.4 (0.5)
High THM level^b	24.8 (9.7)	20.1 (8.6)	0.6 (0.6)	4.2 (2.4)
Winter all sites	10.9 (12.1)	8.4 (9.3)	0.5 (0.6)	1.9 (9.3)
Low THM level^a	1.1 (1.0)	0.9 (0.6)	0.1 (0.3)	0.1 (0.3)
High THM level^b	24.5 (1.4)	18.9 (1.2)	1.1 (0.1)	4.5 (0.2)

ISSN: 1476-069X