polycladin

例句：

1. 1.Polychlorinated biphenyls (PCBs) are highly toxic and have been banned in many countries.
   多氯联苯
2. 2.The PCBs were used in the manufacturing of electrical equipment, but they are now considered hazardous waste.
   PCBs曾被用于制造电气设备，但现在被认为是危险废物。
3. 3. The removal of PCBs from the environment is a major challenge for environmental scientists.
   从环境中去除PCBs是环境科学家面临的重大挑战。