From Trophic Magnification Factors to Multimedia Activity Ratios: Chemometers as Versatile Tools to Study the Fate of Hydrophobic Organic Compounds in Aquatic Ecosystems

We applied passive equilibrium sampling using silicone-based
chemometers
to nine biota species, sediment, and water in a multimedia aquatic
ecosystem. They allowed for direct comparison of the concentration
of regulated and emerging hydrophobic organic compounds in the silicone
across species as well as the comparison of biota with sediments and
water. We derived chemometer-based trophic magnification factors (TMFs)
of diverse compounds that agreed with the traditionally derived TMFs.
Our exploratory work in water demonstrated that equilibrium with newly
designed chemometers can be achieved in few days for compounds with
a log KOW up to 6. We calculated activity
ratios, dividing the concentrations in the silicone equilibrated with
biota by those equilibrated with the abiotic exposure media (sediments
and water), assessing the thermodynamics of bioaccumulation and the
equilibrium state between the ecosystem compartments. They confirmed
that the biota were below equilibrium partitioning relative to sediments
and water, as other studies have described. Silicone-based chemometers
open up new opportunities and applicability in multimedia aquatic
ecosystems for studies that rely on equilibrium partitioning of the
in-situ mixtures of chemicals, such as multimedia
assessments or application of effect-based methods.