Novel organic substances are not easily degraded because organisms lack previous exposure and have thus not evolved specific detoxification and excretion mechanisms, as there has been no selection pressure from them.
新型有机物质不容易降解，因为微生物缺乏以前接触，并因此没有演化出特定的解毒和排泄机制，出现了没有从它们那里来的选择压力。