Anchor: monitoring performance over time.
Entailed: Watching and recording performance over time.
Contradiction: They don't monitor performance, do they?
Contradiction: The people are inside drinking beer.
Contradiction: The period starting in June 2000 and lasting through May 2001 consists of 51 weeks. 
Contradiction: Pesticides and PCBs can be up to 100  ng/L.
Contradiction: A woman sits at a microphone.