2 research outputs found
Occurrence and Spatial Distribution of Microplastics in River Shore Sediments of the Rhine-Main Area in Germany
Plastic
debris is one of the most significant organic pollutants
in the aquatic environment. Because of properties such as buoyancy
and extreme durability, synthetic polymers are present in rivers,
lakes, and oceans and accumulate in sediments all over the world.
However, freshwater sediments have attracted less attention than the
investigation of sediments in marine ecosystems. For this reason,
river shore sediments of the rivers Rhine and Main in the Rhine-Main
area in Germany were analyzed. The sample locations comprised shore
sediment of a large European river (Rhine) and a river characterized
by industrial influence (Main) in areas with varying population sizes
as well as sites in proximity to nature reserves. All sediments analyzed
contained microplastic particles (<5 mm) with mass fractions of
up to 1 g kg<sup>–1</sup> or 4000 particles kg<sup>–1</sup>. Analysis of the plastics by infrared spectroscopy showed a large
abundance of polyethylene, polypropylene, and polystyrene, which covered
more than 75% of all polymer types identified in the sediment. Short
distance transport of plastic particles from the tributary to the
main stream could be confirmed by the identification of pellets, which
were separated from shore sediment samples of both rivers. This systematic
study shows the emerging pollution of inland river sediments with
microplastics and, as a consequence thereof, underlines the importance
of rivers as vectors of transport of microplastics into the ocean
Simulating Effluent Organic Matter Competition in Micropollutant Adsorption onto Activated Carbon Using a Surrogate Competitor
Adsorption onto activated carbon
is a promising option for removing
organic micropollutants (OMPs) from wastewater treatment plant (WWTP)
effluents. The heterogeneity of activated carbons and adsorption competition
between OMPs and adsorbable compounds of the effluent organic matter
(EfOM) complicate the prediction of OMP removals. Thus, reliable and
simple test systems are desirable. For this study, batch experiments
with powdered activated carbon (PAC) were carried out to examine methyl
orange (MO) as a selected surrogate competitor to simulate EfOM adsorption
competition. MO solutions were spiked with carbamazepine (CBZ) as
an indicator substance for well-adsorbing OMPs. On the basis of CBZ
adsorption isotherms in WWTP effluents, MO concentrations for batch
test solutions with identical adsorption competition toward CBZ were
calculated. The calculations were performed according to an empirical
model of CBZ adsorption in the presence of MO, since predictions employing
the ideal adsorbed solution theory (IAST) proved to be inaccurate.
Comparative batch tests with five different PACs were conducted with
WWTP effluent and respective MO batch test solutions. Except for one
PAC, the achieved CBZ removals were very similar in WWTP effluent
and the test solution. Additionally, a universal correlation between
MO and CBZ removals was found for four PACs