Litvinenko was the first known polonium victim, which could help explain why it would've been missed in the investigation of Arafat's death. Investigators also might have missed it because it didn't happen. Pro-peace blogger Richard Silverstein has more details and a considerable amount of speculation about Israel's possible role here. At the New York Times, Isabel Kershner describes Arafat's mixed legacy and the current situation for Palestinians, whose reaction to definitive news that Arafat had been murdered is anybody's guess:
Revered by many as the revolutionary founding father of Palestinian nationalism, he was also reviled, particularly by many Israelis, who considered him a terrorist. He was among three recipients of the Nobel Peace Prize in 1994 for his role in accepting the Oslo accords, a blueprint for peace with Israel, but nearly 20 years later his promises of a Palestinian state remain unfulfilled. Corruption was also rampant under his leadership.
“We have moved from at least having the impression under Yasir Arafat that our national aspirations could be fulfilled to survival mode,” said Zakaria al-Qaq, a political scientist at Al Quds University in East Jerusalem. Nowadays, Mr. Qaq said, Palestinians are concerned about whether or not their salaries will come in, referring to a worsening financial crisis that has caused the Palestinian Authority to delay payment of June salaries to its employees