Chloride. Details on the QA/QC procedures for chloride sample collection and analysis are provided in the Chloride Sample Collection SOP. A summary of these procedures are provided below for collection of a laboratory sample for chloride analysis. Section 8.1.1 provides as summary of QA/QC procedures for measuring chloride with the chloride sensor.
Chloride. Chloride is measured at all sites with active xxxxx. Chloride can be measured by either (1) collecting a chloride sample for analysis at the independent contracted laboratory, Edge, or (2) field measurement using a chloride sensor on the YSI ProPlus. A chloride sample is collected as outlined in the Chloride Sample Collection SOP. The bottle is labeled with the site identifier and other information as detailed in the SOP, and transported to the independent contracted laboratory. Chain of custody forms are used to document sample information, analyses requested, and release of the samples to laboratory staff. A chloride sensor can be attached to the YSI ProPlus to allow for measurement of chloride in a groundwater sample in the field (see Section 7.5.3 and the YSI ProPlus SOP for details). Note that the measurement of chloride using the sensor is a nonstandard method, and that implications on data use are associated with the selection of this chloride measurement option. If data are to be used for regulatory actions, chloride measurement by laboratory analysis is required, as data generated by use of the chloride sensor are less precise and should be used as an estimate of chloride concentration. High chloride measurements obtained by the sensor are used as indicators of potential chloride contamination and trigger the collection of water samples for laboratory chloride analysis. In general, laboratory analysis of chloride is preferred over chloride measurement using the sensor. However, both options are provided within the Ground Water Project to allow for flexibility. Laboratory analysis of chloride in water samples is required annually or three times annually, depending on the site, as part of the Settlement Compliance Project. Laboratory chloride sample collection as part of the Settlement Compliance Project and the Ground Water Project are combined (i.e., when chloride sample collection is required as part of the Settlement Compliance Project during a given month, duplicate chloride samples are not collected as part of the Ground Water Project during that same month). All chloride results are analyzed as part of the Ground Water Project.
Chloride. High temperature causes the desiccation of the bentonite block and induces the precipitation of salts at the interface (chlorides and carbonates mainly). Salt precipitation may play a relevant role in the performance of the carbon steel canister in the repository. Chloride precipitates are well-known for being hygroscopic. This fact could lead to the formation of very concentrated brines on the surface of the canister, what could favour localized corrosion. The most relevant transport processes occurring in the cell may be deduced from the behaviour of chloride. The Cl- distribution is closely related to the water advection, with the formation of saline fronts moving towards the heat focus. Chloride is easily dissolved when less saline water enters the column and is transported as the hydration front moves to the unsaturated areas, as previously Xxxxxx et al. . The advance of Cl- depends on the duration of the experiment. In the FB1 (174 days) experiment, the maximum chloride content was localized in the intermediate zone. As the hydration front advanced, as in FB2 (480 days), chloride was concentrated at the heating zone and the interface (hottest zone). According to the chemical analysis made on FB3 (1593 days), still unsaturated, Cl- concentration is also higher at the interface. Data obtained from the chemical analysis indicate that advection prevails over diffusion as mechanism for salt movement (Figure 7). Bentonite block mmol Cl/100g dry bentonite 12 6 months 15 months 10 54 months Fe powder 6 4 2 0 10 20 30 40 50 60 70 80 Distance from hydration (mm) 90 100 Figure 7. Distribution of soluble chloride found in the three medium- cell tests dismantled. The increase of salinity in the hottest parts of bentonite is possibly caused by the formation of small convection cells generated due to the thermal gradient. At the iron/bentonite interface, water absorbed in bentonite evaporates and moves towards the coldest areas, where it condensates. Liquid water moves again towards the heater. During this movement, the most soluble minerals are dissolved. The hydration front transports salts and saline fronts are generated along the bentonite block. The mobility of these fronts depends on each element. Xxxxxx et al.  however, proposed that the driving force for salt transport would be the increase of salt concentration on the mesopore “external” water with respect to the “surface-influenced” (anion exclusion) micropore water. The preservation of primitive ...
Chloride. Prior to use for field measurements, the YSI ProPlus must be calibrated for chloride using a two- point calibration. A 10.00 mg/L chloride standard is used first for the calibration, followed by the 1,000 mg/L chloride standard. The 10.00 mg/L chloride standard is prepared from the 1,000 mg/L chloride standard following the instructions below:
Chloride. Maintenance activities for the chloride sensor include cleaning and reconditioning. The instructions in this section should be supplemented by detailed information in the YSI ProPlus User’s Manual.
Chloride. Concentrations of chloride in the influent AMD drainage were relatively consistent with values averaging 14 mg/L Cl- during the course of the experiment. 3000 Dissolved Chloride (mg/L Cl-) 2500 2000 1500 1000 500 0 Influent Reactor 1 (LS) Reactor 2 (10:90) Reactor 3 (30:70) Reactor 4 (50:50) Reactor 5 (70:30) Reactor 6 (90:10) Sampling Date Figure 25 Measured chloride concentrations (mg/L Cl-) of the AMD influent and the effluent of each reactor (R1-R6) for each sampling event. 40 Dissolved Chloride (mg/L Cl-) 35 30 Influent Reactor 1 (LS) 25 Reactor 2 (10:90) 20 Reactor 3 (30:70) 15 Reactor 4 (50:50) Reactor 5 (70:30) 10 Reactor 6 (90:10) 5 0 Sampling Date Figure 26 Expanded view of the measured chloride concentrations (mg/L Cl-) of the AMD influent and effluent of each reactor (R1-R6) for each sampling event. Aside from a few spikes in chloride concentrations, the limestone reactor exhibited similar values with respect to the AMD influent (Figure 25). Still, due to the high concentrations of these documented peaks in chloride the limestone only reactor (R1) average 37mg/L chloride over the course of the experiment. Chloride concentrations within the bioreactors (R2-R6) can be separated in three events high concentration, medium concentrations and concentrations near influent AMD. During the first two months average chloride concentrations ranged from 730-1675 mg/L Cl- with maximum values over 2500 mg/L Cl-. Subsequent declines in chloride values occurred during the following four months (November 2012- February 2012) and average concentrations ranged between 42-90 mg/L Cl-. Lastly, during the final six months of the experiment chloride values measured in the samples taken for the effluent of each bioreactor (R2-R6) fell below the average AMD influent values with average concentrations ranging from 9.4-11.5mg/L Cl- (Figure 26).
Chloride. The YSI ProPlus can be equipped with a chloride sensor. The chloride sensor method is not an approved method; therefore, chloride measurements obtained using the YSI ProPlus chloride sensor should be considered approximate. The chloride sensor is sensitive to high ionic strength solutions, such as pH buffers and saltwater. The chloride sensor can only be used in freshwater, and the sensor must be covered during pH sensor calibration and accuracy checks. The QA/QC activities for the chloride sensor include calibration prior to each use and pre-, mid-, and post-run accuracy checks. If the chloride sensor does not meet its acclimation/stabilization criterion during use due to reasons other than natural variability or the chloride sensor is reporting inaccurate readings, corrective actions must be taken and documented per the Water Database User Guide and QMP prior to additional measurements. Periodic chloride sensor maintenance activities include sensor cleaning and reconditioning.