1. Key facts Though the exact number of snake bites is unknown, an estimated 5.4 million people are bitten each year with up to 2.7 million envenomings. Around 81 000 to 138 000 people die each year because of snake bites, and around three times as many amputations and other permanent disabilities...
  2. 水是生命的根本。地球上的淡水有限,而且其质量受到持续的威胁。保持淡水的质量对饮用水的供应、食品生产和娱乐用水十分重要。传染病因子、有毒化学品和放射性危害可影响水的质量。