What might indicate the presence of contamination in ice beyond visible signs?

The presence of contamination in ice can be indicated by measured conductivity. Ice is a crystalline solid and should ideally have low conductivity. However, if impurities or contaminants are present, they can affect the conductivity due to the dissolved ions from salts, chemicals, or biological pollutants. A higher than expected conductivity reading suggests the presence of contaminants, even if there are no visible signs of pollution.

Odor analysis is typically less effective in identifying contamination in ice since any odors may be minimized or masked by the cold temperatures, making it difficult to detect anything unusual.

Temperature stability is also not a reliable indicator of contamination. It could provide information about the thermal properties of the ice but does not provide direct evidence of contamination.

Discoloration in the geometric center may suggest some degree of contamination but does not have the same quantitative importance that measured conductivity does in determining contamination levels. Conductivity provides a more precise means of assessing the quality of ice and the likelihood of contaminants being present.