Elemental Analyzer/Isotope Ratio Mass Spectrometry (EA/IRMS) as a Tool to Characterize Plastic Polymers in a Marine Environment

In the last 60 years, plastic has become a widely used material due to its versatility and wide range of applications. This characteristic, together with its persistence, makes plastic waste a growing environmental problem, particularly in the marine ecosystems. The production of plant-derived biodegradable plastic polymers is assuming increasing importance. Here, we report the results of a first preliminary characterization of carbon stable isotopes (δ13C) of different plastic polymers (petroleum- and plant-derived) and a first experimental study aimed to determine carbon isotopic shift due to polymer degradation in an aquatic environment. The results showed that the δ13C values determined in different packaging for food uses reflect the plant origin for “BIO” materials and the petroleum-derived source for plastic materials. Considering degradation, δ13C values of both bio bags and HDPE bags showed a gradual decrease toward less negative values when kept immersed in seawater, recording a δ13C variation (Δδ13C) of 1.15 and 1.78‰, respectively. With respect to other analytical methods, the characterization of the plastic polymer composition by isotope ratio mass spectrometry is advantageous due to low cost and rapidity of analysis, small amount of sample required, high sensitivity, and the possibility of analyzing colored samples

Vibrations of H 8 Si 8 O 12 , D 8 Si 8 O 12 , and H 10 Si 10 O 15 As Determined by INS, IR, and Raman Experiments †

A detailed study of the vibrational structure of the silasesquioxanes H 8 Si 8 Based on the msd's, the lowest internal torsional frequency was estimated to be 41 ( 7 cm -1

Aquatic Angiosperm Transplantation: A Tool for Environmental Management and Restoring in Transitional Water Systems

Since the 1960s, the Venice Lagoon has suffered a sharp aquatic plant constriction due to eutrophication, pollution, and clam fishing. Those anthropogenic impacts began to decline during the 2010s, and since then the ecological status of the lagoon has improved, but in many choked areas no plant recolonization has been recorded due to the lack of seeds. The project funded by the European Union (LIFE12 NAT/IT/000331-SeResto) allowed to recolonize one of these areas, which is situated in the northern lagoon, by widespread transplantation of small sods and individual rhizomes. In-field activities were supported by fishermen, hunters, and sport associations; the interested surface measured approximately 36.6 km2. In the 35 stations of the chosen area, 24,261 rhizomes were transplanted during the first year, accounting for 693 rhizomes per station. About 37% of them took root in 31 stations forming several patches that joined together to form extensive meadows. Plant rooting was successful where the waters were clear and the trophic status low. But, near the outflows of freshwater rich in nutrients and suspended particulate matter, the action failed. Results demonstrate the effectiveness of small, widespread interventions and the importance of engaging the population in the recovery of the environment, which makes the action economically cheap and replicable in other similar environments

Transport of Electronic Excitation Energy in Dye-Loaded Zeolite L

Zeolite L is an aluminosilicate with one-dimensional channels, having an opening diameter of 7.1 Å. This allows the incorporation of different, electronically non-interacting dye molecules to build an artificial photonic antenna system. The conditions within the channels are such that the dye molecules cannot glide past each other. Hence, a consecutive incorporation leads to crystals with different compartments, where the density of one kind of dye is dominant. The photophysical processes taking place on such dye-loaded zeolite L antenna systems can be studied either on single micrometer or submicrometer sized crystals, on crystals dispersed in a solvent, orcoated as thin layers on a support. The energy transfer process that occurs is of the Förster-type and its transfer rate can be tuned, e.g. by first incorporating the acceptor dyes, in a second step consecutively incorporating different amounts of spacer molecules and then in a third step adding the donor dyes. By selectively exciting the donor, energy transfer to the unexcited acceptor as a function of the amount of spacer molecules can be observed. To make a quantitative analysis, one has to take into consideration the situation at the phase boundaries of the particular compartments. This has been done by modeling the distribution of the dye molecules and empty sites within a zeolite crystal by means of a Monte Carlo simulation