Occurrence of polycyclic aromatic hydrocarbons, microplastics and biofilms in Alqueva surface water at touristic spots.

Freshwater pollution is a huge concern. A study aiming to evaluate physico-chemical characteristics, microbiota, occurrence of two groups of persistent environmental pollutants with similar chemical properties (polycyclic aromatic hydrocarbons- PAHs and microplastics - MPs) in Alqueva's surface water was performed during 2021. Water samples were collected at three spots related to touristic activities (two beaches and one marina) during the Winter, Spring, Summer and Autumn seasons. In addition, the presence of biofilms on plastic and natural materials (stone, wood/ vegetal materials) were assessed and compared. Water quality based on physicochemical parameters was acceptable with a low eutrophication level. PAHs concentration levels were lower than the standard limits established for surface waters by international organizations. However, carcinogenic compounds were detected in two sampling locations, which can pose a problem for aquatic ecosystems. PAHs profiles showed significant differences when comparing the dry seasons with the rainy seasons, with a higher number of different compounds detected in Spring. Low molecular weigh compounds, usually associated with the atmospheric deposition and petroleum contamination, were more prevalent. MPs were detected in all samples except one during the Winter season. The polymers detected were poly(methyl-2-methylpropenoate), polystyrene, polyethylene terephthalate, polyamide, polypropylene, styrene butadiene, polyvinyl chloride and low /high density polyethylene with the last being the most frequent. Biofilms were more often detected on plastics than on natural materials. In addition, biofilms detected on plastics were more complex with higher microbial diversity (e.g., bacteria, fungi/yeast and phytoplancton organisms) and richer in extrapolymeric material. Based on morphological analysis a good agreement between microbiota and microorganism present in the biofilms was found. Among microbiota were identified microorganisms previously linked to plastic and PAHs detoxification suggesting the need for further studies to evaluate the viability of using biofilms as part of a green bioremediation strategy to mitigate water pollution.

Microplastics in the crustaceans Nephrops norvegicus and Aristeus antennatus: Flagship species for deep-sea environments?

Ingestion of microplastics (MPs) has been documented in several marine organisms, but their occurrence in deep-sea species remains almost unknown. In this study, MPs were investigated in two economically and ecologically key crustaceans of the Mediterranean Sea, the Norwegian lobster Nephrops norvegicus and the shrimp Aristeus antennatus. Both the species were collected from 14 sites around Sardinia Island, at depths comprised between 270 and 660 m. A total of 89 and 63 stomachs were analysed for N. norvegicus and A. antennatus respectively, and more than 2000 MPs-like particles were extracted and sorted for identification and characterization by µFT-IR. In N. norvegicus, 83% of the specimens contained MPs, with an average abundance of 5.5 ±â€¯0.8 MPs individual-1, while A. antennatus showed a lower frequency of ingestion (67%) and a lower mean number of MPs (1.66 ±â€¯0.1 MPs individual-1). Composition and size of particles differed significantly between the two species. The non-selective feeding strategy of N. norvegicus could explain the 3-5 folds higher numbers of MPs in its stomach, which were mostly composed of films and fragments derived by polyethylene and polypropylene single-use plastic items. Contrarily, most MPs in the stomachs of A. antennatus were polyester filaments. The MPs abundance observed in N. norvegicus is among the highest detected in Mediterranean species considering both fish and invertebrates species, and provides novel insights on MPs bioavailability in deep-sea habitats. The overall results suggest that both N. norvegicus and A. antennatus, easily available in common fishery markets, could be valuable bioindicators and flagship species for plastic contamination in the deep-sea.

Stability of commercial parenteral lipid emulsions repacking to polypropylene syringes.

To accommodate small fluid volumes, repackaging of intravenous lipid emulsions is frequently performed in hospitals providing parenteral nutrition to neonates and smaller pediatric patients. The physical stability of lipid commercial parenteral emulsions repacked and stored in polypropylene syringe up to 30 days at room temperature, refrigerator and 40°C was determined to establish options for extended storage. Lipid emulsions in the manufacturers' original containers were used as references. Commercial lipid emulsions (20% of oil phase), ClinOleic, Intralipid, Smoflipid, Omegaven and Lipofindin LCT/MCT were repackaged under aseptic conditions in polypropylene syringes and stored at 4°C, 25°C and 40°C without light protection. Samples were assayed periodically over 30 days using validated, stability-indicating methods. Lipid emulsions in the manufacturers' containers stored in the same conditions were as references. Analysis of variance showed differences in the physical parameters due to temperature (p<0.05) and study day (p<0.05) but not the type of the emulsion (p = 0.98). The parenteral lipid emulsions in polypropylene syringe exhibited identical (except Z-avarage at 40°C, t = 30 days) to original containers time-dependent behavior taking into account the mean globule size, pH, and zeta potential measurements. Size of oily droplets of all test conditions remained below the United States Pharmacopeia limits. The results allow safe repacking of commercial lipid emulsion in a syringe, which is a necessary condition for supplying parenteral nutrition using the two-in-one method for newborns. However, longer storage than 12 h of repacked emulsion needs microbiological studies.

Migration of polyolefin oligomeric saturated hydrocarbons (POSH) into food.

POSH are polyolefin oligomeric saturated hydrocarbons, such as oligomers from polyethylene or polypropylene. POSH that have migrated into foods are easily mistaken for mineral oil-saturated hydrocarbons (MOSH). In fact, both POSH and MOSH largely consist of highly isomerised branched and possibly cyclic hydrocarbons, both forming humps of unresolved components in gas chromatography. Chromatograms are reported to show typical elution patterns of POSH and help analysts distinguishing POSH from MOSH as far as possible. Since the structures of the POSH are not fundamentally different from those of the MOSH, it would be prudent to apply the evaluation of the MOSH. However, the migration is frequently beyond that for which safety has been demonstrated. This is shown for a few examples, particularly for powdered formula for babies.

Potable water recovery from As, U, and F contaminated ground waters by direct contact membrane distillation process.

In this study, the feasibility of the direct contact membrane distillation (DCMD) process to recover arsenic, uranium and fluoride contaminated saline ground waters was investigated. Two types of membranes (polypropylene, PP; and polytetrafluoroethylene, PTFE) were tested to compare the permeate production rates and contaminant removal efficiencies. Several experiments were conducted to study the effect of salts, arsenic, fluoride and uranium concentrations (synthetic brackish water with salts: 1000-10,000 ppm; arsenic and uranium: 10-400 ppb; fluoride: 1-30 ppm) on the desalination efficiency. The effect of process variables such as feed flow rate, feed temperature and pore size was studied. The experimental results proved that the DCMD process is able to achieve over 99% rejection of the salts, arsenic, fluoride and uranium contaminants and produced a high quality permeate suitable for many beneficial uses. The ability to utilize the low grade heat sources makes the DCMD process a viable option to recover potable water from a variety of impaired ground waters.

Co-pyrolysis of polypropylene waste with Brazilian heavy oil.

To evaluate the chemical recycling of plastic residues, co-pyrolysis of polypropylene (PP) waste with Brazilian crude oil was evaluated varying the temperature (400°C to 500°C) and the amount of PP fed to the reactor. The co-pyrolysis of plastic waste in an inert atmosphere provided around 80% of oil pyrolytic, and of these, half represent the fraction of diesel oil. This study can be used as a reference in chemical recycling of plastics, specially associated with plastics co-pyrolysis.

Biocomposites from abaca strands and polypropylene. Part I: Evaluation of the tensile properties.

In this paper, abaca strands were used as reinforcement of polypropylene matrix and their tensile mechanical properties were studied. It was found relevant increments on the tensile properties of the abaca strand-PP composites despite the lack of good adhesion at fiber-matrix interface. Afterwards, it was stated the influence of using maleated polypropylene (MAPP) as compatibilizer to promote the interaction between abaca strands and polypropylene. The intrinsic mechanical properties of the reinforcement were evaluated and used for modeling both the tensile strength and elastic modulus of the composites. For these cases, the compatibility factor for the ultimate tensile strength was deduced from the modified rule of mixtures. Additionally, the experimental fiber orientation coefficient was measured, allowing determining the interfacial shear strengths of the composites and the critical fiber length of the abaca strand reinforcement. The mechanical improvement was compared to that obtained for fiberglass-reinforced PP composites and evaluated under an economical and technical point of view.

Polymer additive migration to foods--a direct comparison of experimental data and values calculated from migration models for polypropylene.

To reduce the amount of compliance testing for food contact polymers the use of migration modelling is under discussion and being evaluated by an EU Commission funded project (Evaluation of Migration Models No. SMT4-CT98-7513). The work reported in this paper was exclusively funded by industry to provide data for the independent evaluation of a diffusion based model using eight different samples of polypropylene (PP) covering the range of polymers specification and five commonly used plastics additives. One hundred and fifty experimental migration data have been obtained in triplicate and used to evaluate a Fickian-based migration model in the prediction of specific migration of five additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods, with test conditions of 2h at 121 degrees C, 2h at 70 degrees C and 10 days at 40 degrees C, representing short term exposures at high temperatures and room temperature storage. Predicted migration values were calculated using the Piringer 'Migratest Lite' model by entering the measured initial concentration of additive in the polymers(Cp.0) in to the equations together with known variables such as additive molecular weight, temperature and exposure time. Where necessary the data generated in this study have been used to update the model. The results indicate the Piringer migration model, using the 'exact' calculations of the Migratest Lite program, predicted migration values into olive oil close to, or in excess of, the experimental results for > 97% of the migration values generated in this study. For all measurements, the predicted migration from the Migratest Lite program was greater than 70% of the observed value. This study has identified the possibility, that random co-polymers of propylene and ethylene give higher migration than other grades of polypropylenes and could be treated as a separate case. However, further work on more samples of random co-polymers is required to confirm this finding.