TABLE 1.

Geochemical parameters measured in the trench water

Parameter	Value at sampling day (date)a					Maximum background concnb
	0 (23 April)	4 (27 April)	6 (29 April)	21 (14 May)	47 (9 June)
Field parameters
pH	6.3	6.22	6.35	6.5	6.6	NA
Eh (mV)c	247	177	192	117	147	NA
DO (mg/liter)	0.5	0.6	0.6	0.6	0.5	NA
TDSh (g/liter)	0.115	0.12	0.118	0.156	0.185	NA
Temp (°C)	20.9	19.5	19.8	18.2	19.2	NA
Water level (m)d	−0.89	−1.26	−1.36	−1.55	−1.64	NA
Radiochemistry (activity in Bq/liter)e
241Am (UF)f	15.68 ± 0.38	22.85 ± 0.58	22.09 ± 0.55	25.4 ± 0.64	27.8 ± 1.49	NA
241Am (F)g	7.17 ± 0.19	11.24 ± 0.48	12.15 ± 0.22	21.56 ± 0.59	24.71 ± 1.3	NA
239+240Pu (UF)f	30.44 ± 0.9	40.53 ± 1.22	41.71 ± 1.29	43.66 ± 1.27	45.6 ± 2.43	NA
239+240Pu (F)g	6.46 ± 0.21	16.28 ± 0.51	17.73 ± 0.56	35.11 ± 0.99	26.93 ± 2.36	NA
Chemistry
DOC (mg/liter)	4.07	4.15	5.30	5.91	6.77	0.04
Fe(II) (mM)	0.34	0.39	0.45	0.75	0.92	<0.01
Fe (mM)	0.42	0.45	0.46	0.80	0.99	<0.01
Na (mM)	0.73	0.70	0.70	0.79	0.85	<0.01
SiO2 (mM)	0.36	0.37	0.37	0.44	0.52	<0.01
Cl− (mM)	0.51	0.51	0.51	0.54	0.54	0.01
Mg (mM)	0.08	0.08	0.08	0.11	0.12	<0.01
Ca (μM)	33.43	30.69	34.18	41.42	50.40	0.25
K (μM)	31.71	32.48	32.74	31.97	32.23	0.31
Mn (μM)	1.80	1.86	1.64	2.00	2.55	<0.02
P (μM)	4.20	4.20	5.17	7.10	9.69	<1.6
S (μM)	62.36	62.36	59.25	28.06	6.24	<3.11
F− (μM)	2.63	2.11	2.11	3.16	4.21	<0.53
Br− (μM)	2.63	2.50	2.50	3.25	4.01	<0.13
I− (μM)	4.96	4.81	5.12	7.88	11.03	<0.22
NO3− (μM)	0.24	0.24	0.55	0.00	0.00	<0.01

^aDay count from the first day with no precipitation after the rainfall event. All dates are for the year 2015.

^bHighest concentrations measured on multiple blanks (n > 5) processed in parallel with trench samples. NA, not applicable.

^cCorrected values against standard hydrogen electrode.

^dDepth below ground surface.

^ePlus or minus 1 standard deviation.

^fFiltered through 0.45-μm filter (soluble/colloidal).

^gUnfiltered (total).

^hTDS, total dissolved solids.