Two more cases of mixtures that include a forbidden item are discussed on today’s daf (=page).
1. Rav Nahman quoted Rabbah bar Avuha in the name of Rav as teaching that in a case of a signet ring of avodah zarah(=idol worship) that was mixed with others so that the entire collection was forbidden, if a single ring falls into the Yam ha-Gadol we will assume that it was the forbidden ring that fell, and all of the others are permitted.
2. Resh Lakish teaches that if a barrel of terumah – tithes, permitted only to a kohen – were mixed with other barrels so that none could be eaten, except by a kohen, should one of them fall into Yam ha-Melah, then we will assume that it was the barrel of terumah that fell, and all of the others are permitted.
In the first case, Rashi explains that the signet ring was decorated with an idol, and the mixture is forbidden becauseavodah zarah cannot become nullified. Tosafot suggest that it is the unique importance of the ring that creates the situation that keeps it from becoming nullified. The Yam ha-Gadol referred to in this case is the Mediterranean Sea, as it is called in Sefer Yehoshua (1:4). This name separates the Mediterranean from other bodies of water in Israel, like the Kinneret and the Dead Sea.
Yam ha-Melah mentioned in the second case is, in fact the Dead Sea, which is also referred to in Talmudic texts as The Sea of Sedom. It is common for the Gemara to suggest that a forbidden object be thrown into Yam ha-Melah since there are no fish and therefore no fisherman who might chance across the object and take it for personal use. It is also possible that the high salt and mineral content of the Dead Sea were seen by the Sages as elements that would ruin anything thrown into it.
After bringing these two cases, the Gemara explains why both of these cases are needed since we would not be able to derive one situation from another.