Table 3.

Comparison of background element levels in blank filter paper vs. adjacent filter paper.

Element	Median lot W-031	Median lot W-041	Median lot W-051	Median adjacent paper	Median ratio adjacent paper/lot W-031	Median ratio adjacent paper /lot W-041	Median ratio adjacent paper /lot W-051
Al1	3.01	0.61	0.75	1.62	0.54	2.65	2.16
Ba1	0.44	0.36	0.09	0.46	1.05	1.27	5.14
Ca1	220.28	212.48	136.82	181.54	0.82	0.85	1.33
Cd2	4.66	3.90	0.63	9.20	1.97	2.36	14.70
Ce2	6.06	4.83	0.57	9.50	1.57	1.97	16.53
Co2	47.81	35.30	53.12	3.50	0.07	0.10	0.07
Cr2	8.75	8.84	7.34	14.10	1.61	1.59	1.92
Cs2	0.10	0.05	0.07	0.90	8.65	16.43	12.29
Cu1	0.40	0.12	0.09	0.28	0.72	2.39	3.16
Fe1	2.49	2.45	1.39	4.29	1.72	1.75	3.10
K1	2.06	3.20	7.35	948.04	459.11	296.51	129.06
Li2	1.85	2.62	6.00	3.40	1.83	1.30	0.57
Mg1	31.87	40.95	43.37	30.63	0.96	0.75	0.71
Mn1	1.02	0.67	0.16	0.90	0.88	1.34	5.75
Mo2	1.75	0.74	5.28	23.30	13.32	31.67	4.41
Na	58.30	72.31	94.20	646.28	11.09	8.94	6.86
Ni2	26.07	17.79	15.16	58.70	2.25	3.30	3.87
P1	9.60	11.94	1.32	34.52	3.60	2.89	26.23
P22	24.24	15.61	5.47	40.10	1.65	2.57	7.33
R22	2.89	3.09	7.27	1010.90	349.84	327.20	139.03
S1	8.57	11.36	19.07	25.45	2.97	2.24	1.33
S22	0.11	−0.04	0.21	3.40	30.35	−90.31	16.29
Sr1	0.39	0.35	0.21	0.35	0.91	1.00	1.67
Ti2	37.23	15.66	18.84	32.40	0.87	2.07	1.72
Tl2	−0.01	0.04	0.04	0.04	−7.97	1.00	0.99
U2	0.28	0.19	0.12	0.20	0.72	1.05	1.66
V2	2.27	2.80	3.42	3.70	1.63	1.32	1.08
Zn1	0.51	0.43	0.18	1.77	3.49	4.09	10.02

¹Concentration in ng/mg paper extracted

²Concentration of element in pg/mg paper extracted)