text: POCIS can be deployed in a wide range of aquatic environments including stagnant pools, rivers, springs, estuarine systems, and wastewater streams. However, there has been little research into the use of POCIS in strictly marine environments. Prior to deployment of a POCIS device, it is essential to select a study site that will maximize the effectiveness of the sampler. Selecting an area that is shaded will help prevent light sensitive chemicals from being degrading. The site should also allow the sampler to be submerged in the water without being buried in the sediment. It is ideal to place the sampler in moving water in order to increase sampling rates, however, areas with an extremely turbulent water flow should be avoided as to prevent damage to the POCIS device. Passive samplers are very vulnerable to vandalism and it is therefore important to secure the sampler in areas that are not easily visible and that are away from areas frequently used by people.
  POCIS samplers can be deployed for a period of time ranging from weeks to months. The shortest deployment lengths are typically 7 days but average 2–3 months. It is important to have a long enough deployment period to allow for adequate detection of contaminants at ambient environmental concentrations. Often, the two different types of POCIS devices will be deployed together in order to provide the greatest understanding of contamination. It is also important to deploy enough POCIS devices to ensure a large enough sample of contaminant is recovered for chemical analysis. An estimate or the number of samplers needed at a given site can be determined by the following equation.
  ::::R x t x n x C x P x E > MQL x V 
  ::where
  ::*C is the predicted environmental concentration of the contaminant 
  ::*t is the deployment time in days 
  ::*R is sampling rate in liters of water extracted by the passive sampler per day(L/day) 
  ::*P is the overall method recovery for the analyte (expressed as a factor of one; ::therefore 0.9 is used for 90 percent recovery), 
  ::*n is the number of passive samplers combined into a single sample, 
  ::*E is the fraction of the total sample extract which is injected into the ::instrument for quantification
  ::*MQL is the method quantification limit
  ::*V is the volume of standard injection (commonly 1 μL).