Parah 8:7-8

Parah 8:7

Whatever makes trumah unfit renders liquid unclean in the first degree; the liquid can then convey one degree of impurity to food and render trumah unfit in one degree; the exception is a t’vul yom. We see that the impurity renders the liquid unclean but it doesn’t render the food unclean; rather, the liquid renders the food unclean.

Parah 8:8

All seas are like a mikvah as per Genesis 1:10, “The gathering of the waters He called seas.” (“The gathering of waters” is “mikvei mayim” in Hebrew.) This is the opinion of Rabbi Meir. Rabbi Yehuda says that only the Great Sea (the ocean and/or the Mediterranean Sea) is like a mikvah; the verse says “seas” (in the plural) because there are many kinds of sea water in it. Rabbi Yosi says that all seas render clean through their flowing water but they aren't suitable for a zav, a metzora and for preparing the water of the red heifer.