TITLE: Water sample collection and processing
AUTHORS: isis.scott

[DESCRIPTION]
This protocol includes the guidelines for water sample collection and processing (CEAP samples)

[STEPS]
SECTION: SCOPE
1. This standard operating procedure (SOP) describes the procedure for the collection and processing of water samples in the Snake River Basin. Water samples are collected often for assessing water quality in the irrigation return flows to the Snake River. The samples are analyzed for pH, electrical conductivity (EC), total suspended solids (TSS), total Kjeldahl nitrogen (N), FIA-analyzed nitrate, ammonia and chloride, and digested for ICP analysis of Al, Ca, Fe, K, Mg, Na, P, S, and Zn. 
SECTION: Preparing for sample collection
2. Labelling bottles:
SECTION: Preparing for sample collection
3. Pipette 150 µL  of 1 Molarity (M)  or 6.2 mg/mL boric acid solution into centrifuge tubes 

SECTION: Preparing for sample collection
2.1. Label 2-L bottles and 60-mL bottles with sample location and sample number
SECTION: Preparing for sample collection
2.2. Label 15-mL centrifuge tubes with the sample location, sample number ,date and initials. 
SECTION: Preparing for sample collection
4. Petri dishes and filter membranes: 
 

 


 


SECTION: Sample collection
0.27. Place 2-L bottle in the sample rod. Submerge bottle into stream and filling it twice and discarding the water to rinse bottle. Collect sample by lowering bottle through the entire depth of stream. 
SECTION: Preparing for sample collection
4.1. Lay out petri dishes and add one membrane filter to each dish. Place then



 in the oven at 60 °C    
SECTION: Preparing for sample collection
4.2. 
Place petri dishes in the desiccator. Apply vacuum until it stops hissing, and disconnect vacuum tubing. Turn the valve to maintain vacuum. Keep the dishes in the desiccator for 60 min . 

SECTION: Preparing for sample collection
4.3. Weigh petri dishes + filter. Record weights in the worksheet. 
SECTION: Sample processing: filtering for FIA analysis
5. Sample filtering will depend on the number of sampling locations to be visited. If samples are collecting in one location only (e.g., water quality ponds), samples are to be filtered on site. If more sampling locations are to be visited (e.g. CEAP samples), all 2-L samples are brought into the lab and filtering will occur on the day or day after of collection. Unfiltered samples need to be stored in walk-in cooler if not filtered on the same day of collection. The steps for filtering are described below: 
SECTION: Sample processing: filtering for FIA analysis
5.1. Transfer a 15-mL aliquot of water sample from the 2-L bottle using a syringe. 

SECTION: Sample processing: filtering for FIA analysis
5.2. Attach a 0.45 µm syringe filter and filter the water into a 15-mL centrifuge tube containing boric acid.
SECTION: Sample processing: filtering for FIA analysis
5.3. Filtered samples are to be stored in the refrigerator in Room 119 until analysis. 
SECTION: Sample processing: pH end EC measurements
7. When 2-L water samples are at room temperature, measure pH and EC using the pH and EC meters in the Annex. 
SECTION: Sample processing: pH end EC measurements
7.1. pH and EC meters must be calibrated before measuring. For EC, use 84 and 1413 µS/cm calibrators. For pH, use the 7 and 10 calibrators.  
0.27. 
SECTION: Sample processing: unfiltered samples
6. Transfer a 50-mL aliquot of water sample from the 2-L bottle to the 50-mL bottles and store them in the refrigerator in Room 119 until TKN analysis. This step can also be conducted during the TSS analysis, if preferred. 
SECTION: Sample processing: TSS  analysis
8. Place blank 0.45 µm membrane filters on each of the cylinder attachments on the filtration manifold using tweezers. Cover with the plastic cylinders. 
SECTION: Sample processing: TSS  analysis
8.2. Collect a 150 mL aliquot using the turkey baster into the volumetric flask and transfer it to the vacuum cylinder. The final amount of water that is filtered for TSS determination will depend on the amount of sediment in the sample. I there's little sediment, the volume filtered should be increased (i.e., if the volume added of water sample is filtered in less than ~2 minutes, add another 150 mL of sample to cylinder). For high-sediment samples, the volume to be filtered will need to be reduced to 50 mL  or 100 mL . 

SECTION: Sample processing: TSS  analysis
8.1. Place water sample on stirrer and stir until vortex is formed and the sediment is in suspension. 
SECTION: Sample processing: TSS  analysis
8.4. Apply vacuum to manifold by opening the valves for the cylinders being used.
SECTION: Sample processing: TSS  analysis
8.3. Rinse the graduated cylinder with DI water and add that volume to the vacuum cylinder to account for the residual sediment. 
SECTION: Sample processing: TSS  analysis
8.5. Once sample filtering is complete, remove the cylinders, and place the membrane filters back onto the Petri dishes using the tweezers. 
SECTION: Sample processing: TSS  analysis
8.6. Rinse cylinders, turkey baster, magnetic stirrer, and volumetric flask before moving to the next sample.