[2] The POCIS sampler mimics the respiratory exposure of organisms living in the aquatic environment and can provide an understanding of bioavailable contaminants present in the system.
[4] The initial type of passive sampler developed for aquatic monitoring purposes was the semipermeable membrane device (SPMD).
[5] In the late 1990s research was underway to develop a new passive sampler in order to monitor HpOCs with a log Kow value of less than 3.
It gathered more support in the early 2000s as concern increased regarding the effects of pharmaceutical and personal care products in surface waters.
The USGS Columbia Environmental Research Center (CERC) is a self-proclaimed international leader in the field of passive sampling.
An international workshop and symposium on passive sampling was held by the USGS in 2013 to connect developers, policy makers and end users in order to discuss ways of monitoring environmental pollution.
[6] The POCIS device was developed and patented by Jimmie D. Petty, James N. Huckins, and David A. Alvarez, of the Columbia Environmental Research Center.
[1] Integrative passive samplers are an effective way to monitor the concentration of organic contaminants in aquatic systems over time.
Each disk consists of a solid sorbent sandwiched between two polyethersoulfone (PES) microporous membranes which are then compressed between two stainless steel rings which expose a sampling area.
Stainless steel rings, or other rigid inert material, are essential to prevent sorbent loss as the PES membranes are not able to be heat sealed.
This canister is usually made of stainless steel or PVC and works to deflect debris that may displace the POCIS array during its deployment.
The sampling rate of POCIS can vary with changes in the water flow, turbulence, temperature, and the buildup of solids on the sampler’s surface.
During the integrative phase of uptake, a passive sampling device accumulates residues linearly relative to time, assuming constant exposure concentrations.
[5] In order to estimate the ambient water concentration of contaminants sampled by a POCIS device, there must be available calibration data applicable for in situ conditions regarding the target compound.
[3] POCIS can be deployed in a wide range of aquatic environments including stagnant pools, rivers, springs, estuarine systems, and wastewater streams.
[5] Applicable classes of contaminants measured by POCIS are pharmaceuticals, household and industrial products, hormones, herbicides, and polar pesticides (Table 1).
A general POCIS design contains a sorbent that is used to collect pesticides, natural as well as synthetic hormones, and wastewater related chemicals.
It can also be argued that the use of POCIS is a more relevant from an ecotoxicological perspective as the use of a passive sampler mimics the uptake of compounds by organisms.
Another strength in using bioassays to test environmental samples is that they can provide an integrative measure of the toxic potential of a group of chemical compounds, rather than a single contaminant.
Contaminants applicable to the use of an SPMD include, but are not limited to, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, dioxins, and furans.
[3] The SPMD consist of a thin-walled, nonporous, polyethylene membrane tube that is filled with high molecular weight lipid.
[3] The POCIS sampler already serves as a versatile, economical, and robust tool for monitoring studies and observing trends in both space and time.