Groundwater Arsenic Collection Containers and Preservation for ICP-MS Analysis

I am working on my master's of water resources science research in hydrogeology and will be collecting samples from wells (agricultural, livestock, and residential) to analyze for TOTAL arsenic.   I have conducted a thorough review of the literature and consulted two of the lab managers I will be working with, but I still do not have a clear answer to the proper collection procedures.  I will initially be screening the samples with a quick test kit and a colorimeter, then collect samples (60ml should be sufficient) to use for analysis in ICP-MS.   My question is, is HDPE or polypropylene used to collect the samples?  Since I will only be preserving the samples for less than a week, does it matter which one I use?  Additionally, multiple methods refer to solely nitric acid as a rinse and preservation (ph