Three monitor wells on public state land between Phelps Dodge Sierrita tailings dam and
Monitor Well No. MH-11
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8/14/03 |
5.2 ± 1.1 |
14.0 |
ND |
ND |
734 ± 79.4 |
4.0 ± 0.9 |
ND |
1.1 ± 0.5 |
0.0062 |
12/02/03 |
8.0 ± 1.3 |
24.5 ± 7.8 |
0.9 ± 0.4 |
ND |
673 ± 48.1 |
3.1 ± 0.9 |
ND |
2.1 ± 0.7 |
0.0067 |
3/16/04 |
5.8 ± 1.3 |
12.7 ± 7.0 |
ND |
ND |
618 ± 56.4 |
3.2 ± 0.7 |
ND |
2.1 ± 0.6 |
0.0059 |
Monitor Well No. MH-12
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12/02/03 |
5.3 ± 1.6 |
19.7 ± 4.7 |
0.5 ± 0.4 |
ND |
535 ± 45.9 |
2.7 ± 0.9 |
0.2 ± 0.2 |
0.9 ± 0.5 |
0.0045 |
3/15/04 |
4.9 ± 1.8 |
24.4 ± 4.2 |
0.5 ± 0.3 |
ND |
2.9 ± 0.7 |
ND |
ND |
1.0 ± 0.4 |
0.0042 |
Monitor Well No. MH-13
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8/14/03 |
10.8 ± 1.6 |
23.7 ± 2.6 |
ND |
ND |
ND |
6.4 ± 1.1 |
0.4 ± 0.3 |
2.4 ± 0.7 |
0.0099 |
12/02/03 |
13.0 ± 2.5 |
37.5 ± 7.8 |
0.5 ± 0.3 |
ND |
ND |
8.0 ± 1.2 |
0.3 ± 0.2 |
2.6 ± 0.7 |
0.0098 |
3/11/04 |
9.5 ± 3.1 |
13.3 ± 7.0 |
ND |
ND |
ND |
6.8 ± 1.2 |
ND |
2.8 ± 0.8 |
0.0082 |
MCLG** |
0 |
0 |
Ra-226+ 228 = 0 |
None |
None |
None |
None |
0 |
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MCL*** |
15 pCi/l |
4 mrem/yr |
Ra-226+ -228 = 5 |
None |
None |
None |
None |
0.03 mg/l |
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* No standard set for Radon even though it is on the World Health Organization's list for lung cancer.
** Maximum Contaminant Level Goal, 40 C.F.R. § 141.55.
***Maximum Contaminant Levels, 40 C.F.R. § 141.66(b) [for Ra-226+-228]; (c) [for gross alpha activity]; (d) [for beta particle and [photon radioactivity];
and (e) [for uranium].
Comments: From this data, particularly the Radon readings, one can see that there is some impact of the seepage from the tailings pond slurry. However, to draw any conclusions, we have to get an ambient level of the components in the aquifer. We are attempting to acquire that data.