A flow of contaminated liquid phase water migrates toward the freeze front and {HEAD ~ a concentration} of {TAIL ~ impurities} is established in front of the advancing freeze front 
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A flow of contaminated liquid phase water migrates toward the freeze front and { HEAD ~ a concentration } of { TAIL ~ impurities } is established in front of the advancing freeze front
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH