CAN IMPROPER SAMPLING TECHNIQUES CAUSE WET FAILURES?
It is very important that sampling equipment is cleaned appropriately, in order to insure that samples are representative of the effluent and no confounding factors are present (i.e. to remove any possible contamination). If the facility sampler or a portable sampler is used, the tubing should be replaced with new tubing, including the pump head tubing. If this is not possible, all tubing should be cleaned and rinsed according to Section 1 of the Methods Manual. Artifactual toxicity may occur when sampling equipment is not cleaned regularly. Microorganisms can colonize surfaces that are in contact with the effluent. Some of these microbes can produce endotoxins that are toxic to the test organisms. Before sampling, you should replace all of the tubing and clean any parts that contact the sample. It is also important that a representative sample be obtained under “normal” operating conditions unless there is a specific reason to collect a sample during an atypical situation. Collection