2018-04-10_REVISION - M1977493 - Laserfiche WebLink

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Eagle Park Reservoir Company April 10, 2018 Page 2 of 3 LRE'S COMMENTS LRE has reviewed the rationale for discontinuing the above parameters from groundwater and surface water monitoring and has the following two comments: 1. LRE supports the proposal to discontinue all of the above parameters with the exception o arsenic mercury, and silver— See Comment 2 below from both groundwater and surface water quarterly sampling. However, LRE recommends that the full suite of original groundwater and surface water parameters be sampled at least once annually, preferably in the early spring. Conducting annual sampling for the full suite of original groundwater and surface water parameters (the expanded baseline monitoring list of analytes) is needed periodically to allow Climax, EPRC, and the regulatory agencies to identify any water quality changes that may not be detected with quarterly analyses that are limited to the indicator parameters. Periodic sampling and analysis for the expanded baseline monitoring parameters would also provide the data needed to verify the relationships between the indicator parameters and the additional parameters in the baseline monitoring list and the ongoing validity of the indicator parameter list. Additionally, it is important to note that the "Data Analysis" in TR -27, Section 6.3 applies to all parameters, not just to the indicator parameters/Numeric Protection Levels (NPLs), and annual sampling of the full suite of parameters would further support periodic trend analyses for these additional parameters. 2. The following parameters should be retained on the quarterly indicator parameter lists for both the groundwater and surface water sampling, as the surface water standards are very low, and the parameters have not been analyzed at Detection Limits (DLs) that are low enough to establish ambient conditions as needed to support the data analysis (TR -27, Section 6.3). Arsenic is of particular concern because ambient concentrations in Eagle Park Reservoir and the East Fork of the Eagle River exceed the applicable surface water standard of 0.02 µg/L (water + fish). As such these parameters should be retained in the quarterly sampling for both groundwater and surface water, and the detection limit should be decreased for these parameters so that ambient conditions can be established and ground water concentrations can be compared to conditions in adjacent surface water bodies and to the applicable surface water standards. Table 1. Comparison of Climax Detection Limits to Readily Available Laboratory Detection Limits and Adjacent Surface and *Assumes hardness of 100 mg/L when applicable "Regulation 41 LRE understands laboratory Us for arsenic are higher than the currently applicable standards. However, laboratory analysis methods for arsenic have improved with time, and it should also be noted that the standards for arsenic have become more stringent over time. Furthermore, the Water Quality Control Division is currently in the process of reviewing the water + fish standard LeonardRice ENGINEE�S.IN[ Ground MS Parameter Groundwater Surface Water Readily Available Surface WQS Ground WQS DL L DL (ug/L) DL tq/L) (ug/L)* (ug/L)** Arsenic 0.2 (dissolved) 0.2 (tot. rec.) 0.07 0.02 10 Mercury 0.2 (dissolved) 0.2 (tot.) 0.05 0.01 2 Silver (Dis) 10 10 0.01 0.08 SO *Assumes hardness of 100 mg/L when applicable "Regulation 41 LRE understands laboratory Us for arsenic are higher than the currently applicable standards. However, laboratory analysis methods for arsenic have improved with time, and it should also be noted that the standards for arsenic have become more stringent over time. Furthermore, the Water Quality Control Division is currently in the process of reviewing the water + fish standard LeonardRice ENGINEE�S.IN[