Packing water samples

[ebutler24]

Good  morning:

Tomorrow I am traveling from Amarillo, TX to  San Diego, CA for the purpose of collecting water samples for a project. Instead of shipping them overnight through USPS I thought it might be more cost-effective to take them with me on my return flight to Amarillo. I have placed water samples in my check-in luggage before. However, in this instance I need keep them cold (near 4 degrees C) in order to ensure that what we observe in the water is the same as when it was collected. I understand that I can use dry ice to keep the samples cool (no more than 5.5 lbs) but I am not 100% sure what type of cooler I need to use. I know I cannot use a polystyrene (aka styrofoam) type cooler but what other options would I have?  Can I simply just use a typical plastic cooler used for outdoor recreation?

Thanks.

[rtbarron · Accepted solution]

Plastic coolers are fine.

Here's what I found on the Southwest website:

Refrigerants: Shipments packed in wet ice will not be accepted unless the ice is contained in sealed polyethylene bags (Ziploc® bags). Frozen gels or dry ice/carbon dioxide are the preferred refrigerants. Dry ice/carbon dioxide may be used as a refrigerant for perishables under the following limitations:

• Dry ice/carbon dioxide may not weigh more than 5.5 pounds in checked or carryon baggage.
• The package must be designed to permit the release of carbon dioxide gas to prevent buildup of pressure.
• The outside of the container must be marked "dry ice" or "carbon dioxide solid." The net weight of the dry ice and the contents of the package must also be shown. A Southwest Airlines Dry Ice Label (WN-659) may be used to meet these marking requirements.
  
  
  

[ebutler24]

Thank you.