2 research outputs found
Using Linoleic Acid Embedded Cellulose Acetate Membranes to in Situ Monitor Polycyclic Aromatic Hydrocarbons in Lakes and Predict Their Bioavailability to Submerged Macrophytes
To
date no passive sampler has been used to predict bioavailability
of contaminants to macrophytes. Here a novel passive sampler, linoleic
acid embedded cellulose acetate membrane (LAECAM), was developed and
used to in situ measure the freely dissolved concentrations of ten
polycyclic aromatic hydrocarbons in the sediment porewaters and the
water columns of two lakes in both winter and summer and predict their
bioavailability to the shoots of resident submerged macrophytes (Potamogeton malainus, Myriophyllum
spicata, Najas minor All., and Vallisneria natans (Lour.) Hara). PAH sampling by LAECAMs could reach equilibrium within 21 days.
The influence of temperature on LAECAM-water partition coefficients
was 0.0008–0.0116 log units/°C. The method of LAECAM was
comparable with the active sampling methods of liquid–liquid
extraction combined with <i>f</i><sub>DOC</sub> adjustment,
centrifugation/solid-phase extraction (SPE), and filtration/SPE but
had several advantages. After lipid normalization, concentrations
of the PAHs in LAECAMs were not significantly different from those
in the macrophytes. In contrast, concentrations of the PAHs in the
triolein containing passive sampler (TECAM) deployed simultaneously
with LAECAM were much higher. The results suggest that linoleic acid
is more suitable than triolein as the model lipid for passive samplers
to predict bioavailability of PAHs to submerged macrophytes
Triolein Embedded Cellulose Acetate Membrane as a Tool to Evaluate Sequestration of PAHs in Lake Sediment Core at Large Temporal Scale
Although numerous studies have addressed sequestration
of hydrophobic
organic compounds (HOCs) in laboratory, little attention has been
paid to its evaluation method in field at large temporal scale. A
biomimetic tool, triolein embedded cellulose acetate membrane (TECAM),
was therefore tested to evaluate sequestration of six PAHs with various
hydrophobicity in a well-dated sediment core sampled from Nanyi Lake,
China. Properties of sediment organic matter (OM) varying with aging
time dominated the sequestration of PAHs in the sediment core. TECAM-sediment
accumulation factors (MSAFs) of the PAHs declined with aging time,
and significantly correlated with the corresponding biota-sediment
accumulation factors (BSAFs) for gastropod (<i>Bellamya aeruginosa</i>) simultaneously incubated in the same sediment slices. Sequestration
rates of the PAHs in the sediment core evaluated by TECAM were much
lower than those obtained from laboratory study. The relationship
between relative availability for TECAM (MSAF<sub>t</sub>/MSAF<sub>0</sub>) and aging time followed the first order exponential decay
model. MSAF<sub>t</sub>/MSAF<sub>0</sub> was well-related to the minor
changes of the properties of OM varying with aging time. Compared
with chemical extraction, sequestration reflected by TECAM was much
closer to that by <i>B. aeruginosa</i>. In contrast to <i>B. aeruginosa</i>, TECAM could avoid metabolism and the influences
from feeding and other behaviors of organisms, and it is much easier
to deploy and ready in laboratory. Hence TECAM provides an effective
and convenient way to study sequestration of PAHs and probably other
HOCs in field at large temporal scale