. Author manuscript; available in PMC: 2015 Jan 7.

Published in final edited form as: Environ Sci Technol. 2013 Dec 16;48(1):157–164. doi: 10.1021/es403863m

Table 2.

Distribution of concentration ratios between repeat samples (Round 2/Round 1)^a for major PCBs, N=201 pairs

PCBs	Min	25^th	Med	75^th	Max	% <1
PCB-28	0.02	0.45	0.77	1.1	110	66
PCB-52	0.04	0.52	0.74	1.2	36	68
PCB-101	0.05	0.43	0.77	1.3	16	63
PCB-105	0.03	0.44	0.77	1.5	20	61
PCB-118	0.02	0.43	0.79	1.3	19	60
PCB-138	0.02	0.24	0.44	0.8	6.2	80
PCB-153	0.05	0.41	0.79	1.5	8.8	58
PCB-180	0.005	0.39	0.84	1.1	18	56

Min = minimum; Med = median; Max = maximum; 25^th = 25^th percentile; 75^th = 75^th percentile; % < 1 = Percent of homes with a ratio less than one

Concentration ratio between repeat samples < 1 indicates decrease in PCB concentrations between sampling rounds