Passive sampling is a valuable technique for monitoring
concentration levels of hydrophobic persistent organic pollutants (POPs) in the
marine environment. Simple
polymers like silicones or low-density polyethylene are often used for
this purpose. These polymers accumulate POPs when exposed to water, and the
accumulated amounts are used to measure freely dissolved POP concentrations.
Passive sampling is an alternative to biota-based water
quality monitoring (e.g. using mussels or fish), which often suffers from
confounding factors (e.g. trophic level, lipid content, season, age, gender,
and food availability). These factors play no role in passive sampling. A
successful application of passive sampling requires accurate knowledge of the
polymer-water partition coefficients of the monitored POPs.
TIMES issue, no. 61, provides guidance for the measurement of
polymer-water partition coefficients. Considerations for quality assurance and
quality control measures are outlined. Guidance is also given for the
determination of polymer-polymer partition coefficients, which can be used to
harmonize monitoring data that are obtained with different sampler materials.
The guidelines will be useful for determining polymer-water
and polymer-polymer partition coefficients in the best possible way. They can
also be used to evaluate the quality of literature values of these partition
coefficients. This will further strengthen the scientific basis of passive
sampling-based monitoring of POPs in water.