Distribution of U and REE on colloids in granitic groundwater and quality-controlled sampling at the Mizunami underground research laboratory

Progress in Earth and Planetary Science

Table 1 Average chemical concentration of major elements in the MIU groundwaters

Location	Depth (mbgl)	Packer interval (mabh)	Sampling term	pH	Temperature (°C)	Eh (vs. SHE)	Na ⁺	K ⁺	Ca ²⁺	Mg ²⁺	TC	TIC	TOC	Alkalinity	SO ₄ ²⁻	F ⁻	Cl ⁻	NO ₃ ⁻	Br ⁻	NH ₄ ⁺	PO ₄ ³⁻	Si	B
Location	Depth (mbgl)	Packer interval (mabh)	Sampling term	pH	Temperature (°C)	(mV)	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[meq/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]	[mg/L]
07MI07	200	38.7 to 47.2	2010.4.21 to 2012.12.10	8.76 ± 0.15	15.8 ± 5.7	−180 ± 30	82 ± 4	0.4 ± 0.1	12 ± 1	<0.1	14 ± 1	14 ± 1	0.6 ± 0.1	1.2 ± 0.1	13 ± 1	8.9 ± 0.3	77 ± 10	<0.05	0.16 ± 0.05	0.15 ± 0.05	<0.5	6.8 ± 0.1	1.1 ± 0.1
09MI20	300	34.8 to 57.8	2010.4.27 to 2012.12.4	8.44 ± 0.12	19.7 ± 3.9	−110 ± 20	110 ± 7	0.7 ± 0.1	16 ± 3	0.9 ± 0.1	15 ± 1	15 ± 1	0.6 ± 0.1	1.2 ± 0.1	10 ± 1	8.8 ± 0.3	130 ± 20	<0.05	0.23 ± 0.06	0.12 ± 0.04	<0.5	6.7 ± 0.2	1.3 ± 0.1
10MI26	400	37.9 to 49.6	2011.1.15 to 2012.12.5	8.40 ± 0.10	24.1 ± 2.9	−210 ± 30	120 ± 5	0.8 ± 0.1	17 ± 2	0.8 ± 0.1	14 ± 1	13 ± 1	0.6 ± 0.2	1.1 ± 0.1	7 ± 1	8.6 ± 0.3	160 ± 20	<0.05	0.29 ± 0.04	0.12 ± 0.04	<0.5	6.8 ± 0.2	1.5 ± 0.1
ASP-198	300	-	2010.4.2 to 2012.12.18	8.66	22.9	−71	130 ± 7	0.7 ± 0.1	36 ± 4	<0.1	5.1 ± 0.4	4.8 ± 0.4	<0.5	0.41 ± 0.03	0.9 ± 0.2	8.7 ± 0.4	240 ± 20	<0.05	0.48 ± 0.05	0.21 ± 0.03	<0.5	6.8 ± 0.2	1.4 ± 0.1
ASP-199	300	-	2010.4.2 to 2012.12.18	7.99	22.3	−110	130 ± 7	0.7 ± 0.1	37 ± 3	<0.1	5.5 ± 0.5	5.2 ± 0.5	0.8 ± 0.2	0.43 ± 0.03	0.7 ± 0.2	8.7 ± 0.4	240 ± 20	<0.05	0.49 ± 0.06	0.2	<0.5	6.6 ± 0.2	1.4 ± 0.1

On-site measurements of pH, temperature, and Eh for the seepage groundwater were single-point measurements. Groundwater samples were collected from the 07MI07, 09MI20, and 10MI26 boreholes, and from the A-SP-198 and the A-SP-199 water conducting fractures in excavation walls. mabh, meters along borehole (from collar).