化学污染是另一个日益艰巨的挑战，自1950年以来，大约有140,000种化合物被发明出来，其中受过安全性或毒性测试的寥寥无几。
Chemical pollution is another growing challenge, with an estimated 140,000 new compounds having been invented since 1950, far too few of which have been tested for safety or toxicity.