Can bladder pumps become contaminated in wells and then influence sample concentrations?

We have to think about the nature of anything that we dedicate in the sampling system and that includes the well casing itself. Any material that’s not native to the formation has the potential to swerve some contaminants and then potentially desorb. However, any materials that we place into the groundwater, such as the well casing, the pump material, the tubing or otherwise, will swerve until they reach an equilibrium concentration with the contaminants that are present in the water. From there, desorption will generally occur at a fairly low rate unless there is a steep concentration gradient change. In other words, things would have to move from a high concentration to a very low one very rapidly in order to see any desorption and there would have to be significant residence time. Since the water moving through the pump usually takes just a matter of seconds to go from the pump intake to the surface, sorption is really not a concern whatsoever. So, the answer to your question is no, we are not concerned at all about sorption in the pump or other materials affecting the samples.