Endothall – Drinking Water

Laboratory Fee Schedule
Procedure #:  EZZ0070A

Synonym(s): Endothall in Water
Requisition Form G-22
Test Description Endothall, EPA method 548.1
Pre-Approval Needed N/A
Supplemental Information Required N/A
Supplemental Form(s) N/A
Performed on Specimens from (sources) Environmental
Sample/Specimen Type for Testing Drinking Water
Minimum Volume/Size Required Amber glass bottle with Teflon (PTFE) cap liner; 1 quart (1 L)
Storage/Preservation Prior to Shipping
  • Add 80 mg of sodium thiosulfate to the empty container (to dechlorinate)
  • Open the tap and allow the system to flush until the water temperature stabilizes, at least 5 minutes. Turn flow down to a smooth, pencil thin stream.
  • Remove cap from the bottle, tilt, and place under stream.
  • Fill the container with sample water. Shake vigorously for one minute until the sodium thiosulfate is completely dissolved.
  • Iced (4°C)
  • Store samples away from light or heat.
Transport Medium N/A
Specimen Labeling
  • Label each bottle with a water proof marker. 
  • Pre-printing labels is acceptable.   
  • Sample identification must match submission form.
Shipping and Specimen Handling Requirements
  • Ship according to Dangerous Goods Regulations, IATA, and/or CFR 49.
  • Ship on ice (4°C).
Method EPA 548.1
Turn-around Time Samples must be extracted by the lab within 7 days of collection.
  • Sampling equipment must be free of plastic tubing, gaskets or other parts that may leach interfering analytes into the sample.
  • The major potential interferences in this ion-exchange procedure are other naturally occurring ions in water sources, namely, dissolved calcium, magnesium and sulfate.
  • Matrix interferences may be caused by contaminants that are coextracted from the sample. Matrix interferences will vary considerably from source to source, depending on the nature of the matrix being sampled.  The most probable matrix interferences are other organic acids or phenols retained by the column.
Common Causes for Rejection Insufficient quantity, unacceptable specimen type or source, improper shipping conditions, expired media or collection container, discrepancies between specimen label and submission form and/or incomplete or missing submission form, chlorine present in the sample.  
Additional Information Contact the laboratory at (512) 776-7587 for currently supported analyte list.