RESULTS AND DISCUSSION
The method developed uses a binary solvent mixture of ethanol and water
to separate POM from MP debris. Results and the underlying chemistry of
this method are discussed below. A representative selection of the MPs
isolated from POM in wrack line debris at sites in Lavaca Bay is shown
in Figure 1. White blocky particles overwhelmingly dominated the samples
collected. These atypical materials are released at this size and shape
from a nearby industrial facility that produces pre-production plastics.
However, note that there are also small plastics that typically dominate
estuarine systems without an irresponsible industrial polluter. When
viewed at 40x magnification, these typical materials have multiple
colors, shapes, and sizes (Figure 1B1-4).
Isolated microplastics were quantified by mass rather than count due to
their small size. MP constituted 2.62-21.3% (14.8 ± 7.1) of the POM
sample mass and 0.04-0.42% w/v (0.2 ±
9.5) for the surface water. Peninsula Park (PL) had the highest
concentrations of microplastics in both the beach POM and surface water
at 196.6 ± 15.7 mg g-1 and 3.3 ± 1.0 mg
L-1 respectively (Figure 2A). Six-mile (SM) beach had
the lowest MP concentrations at 60.1 ± 29.6 mg g-1 and
0.7 ± 0.3 mg L-1 in the POM and surface water,
respectively.