alternate explainations

based on information that i had from quarterly tests from the CT DEP (now DEEP), i had postulated that a significant rain after an exteneded low rain period might give false negative results for pesticides.
There were logical reasons for this, particularly if the contamination was coming from a "deep" source.
Samples taken 2 weeks ago, during the 5 day period after heavy rains that i was concerned with, gave several samples with both dieldren and chlordane. 
One would have been sufficient to disprove the theory.
Before this i only had one sample that fit the criteria. 
What is most sad about this is that it now sheds a bad light on HOW the samples were collected.
The DEP had made errors previously (and corrected them) and i was hoping this was not the case, but it appears it probably is the case and that error in sample handling might cause more issues than rain.