Occurrence of microplastics (MPs) in the environments have been frequently reported. However, studies on the quantification methods for MPs are still needed. Plastics are polymers of different degrees of polymerization. In this study, alkali assisted thermal hydrolysis was applied to depolymerize two plastics containing ester groups, polycarbonate (PC) and polyethylene terephthalate (PET), in pentanol or butanol system. By determining the concentrations of the depolymerized building block compounds, i.e. bisphenol A (BPA) and para-phthalic acid (PTA), the amounts of PC and PET MPs in the environmental samples were quantified. Recoveries of 87.2-97.1% were obtained for the PC and PET plastics particles spiked in the landfill sludge. The method was successfully applied to determine the occurrence of PC and PET MPs in the samples of sludge, marine sediments, indoor dust, digestive residues in mussel and clam, as well as in sea salt and rock salt. High concentrations of 246 and 430 mg/kg were determined for PC and PET type MP in an indoor dust, respectively. In addition, 63.7 mg/kg of PC and 127 mg/kg of PET were detected in the digestive residues of a clam.
Heavy metals and microplastics have been considered as threats to the marine environment and the interactions between these two pollutants are poorly understood. This study investigates the interactions between metals adsorbed in pellets collected randomly from 19 beaches along the coast of São Paulo State in southeastern Brazil, comparing these levels with those in virgin pellets. The samples were analyzed for Al, Cr, Cu, Fe, Mn, Sn, Ti and Zn by inductively coupled plasma optical emission spectroscopy (ICP-OES). The polymers were solubilized via acid digestion. The highest levels occurred with Fe (227.78 mg kg− 1 – Itaguaré) and Al (45.27 mg kg− 1 – Guaraú) in the same areas, which are closer to the Port of Santos. The metal adsorption on pellets collected is greater than that on virgin pellets. In this context, pellets can be considered to be a carrier for the transport of metals in the environment, even in small quantities.
M.C. Vedolin, C.Y.S. Teophilo, A. Turra, R.C.L. Figueira, Marine Pollution Bulletin, Available online 13 October 2017, In Press
Pacific Ocean trawl samples, stomach contents of laboratory-raised fish as well as fish from the subtropical gyres were analyzed by Raman micro-spectroscopy (RMS) to identify polymer residues and any detectable persistent organic pollutants (POP). The goal was to access specific molecular information at the individual particle level in order to identify polymer debris in the natural environment. The identification process was aided by a laboratory generated automated fluorescence removal algorithm. Pacific Ocean trawl samples of plastic debris associated with fish collection sites were analyzed to determine the types of polymers commonly present. Subsequently, stomach contents of fish from these locations were analyzed for ingested polymer debris. Extraction of polymer debris from fish stomach using KOH versus ultrapure water were evaluated to determine the optimal method of extraction. Pulsed ultrasonic extraction in ultrapure water was determined to be the method of choice for extraction with minimal chemical intrusion. The Pacific Ocean trawl samples yielded primarily polyethylene (PE) and polypropylene (PP) particles >1 mm, PE being the most prevalent type. Additional microplastic residues (1 mm – 10 μm) extracted by filtration, included a polystyrene (PS) particle in addition to PE and PP. Flame retardant, deca-BDE was tentatively identified on some of the PP trawl particles. Polymer residues were also extracted from the stomachs of Atlantic and Pacific Ocean fish. Two types of polymer related debris were identified in the Atlantic Ocean fish: (1) polymer fragments and (2) fragments with combined polymer and fatty acid signatures. In terms of polymer fragments, only PE and PP were detected in the fish stomachs from both locations. A variety of particles were extracted from oceanic fish as potential plastic pieces based on optical examination. However, subsequent RMS examination identified them as various non-plastic fragments, highlighting the importance of chemical analysis in distinguishing between polymer and non-polymer residues.
Sutapa Ghosal, Michael Chen, Jeff Wagner, Zhong-Min Wang, Stephen Wall, Environmental Pollution, Available online 13 October 2017, In Press
Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as “additives”) contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times.
John N. Hahladakis, Costas A. Velis, Roland Weber, Eleni Iacovidou, Phil Purnell, Journal of Hazardous Materials, Volume 344, 15 February 2018, Pages 179-199
We examined whether bacterial assemblages inhabiting the synthetic polymer polyamide are selectively modified during their passage through the gut of Mytilus edulis in comparison to the biopolymer chitin with focus on potential pathogens. Specifically, we asked whether bacterial biofilms remained stable over a prolonged period of time and whether polyamide could thus serve as a vector for potential pathogenic bacteria. Bacterial diversity and identity were analysed by 16S rRNA gene fingerprints and sequencing of abundant bands. The experiments revealed that egested particles were rapidly colonised by bacteria from the environment, but the taxonomic composition of the biofilms on polyamide and chitin did not differ. No potential pathogens could be detected exclusively on polyamide. However, after 7 days of incubation of the biofilms in seawater, the species richness of the polyamide assemblage was lower than that of the chitin assemblage, with yet unknown impacts on the functioning of the biofilm community.
Katharina Kesy, Alexander Hentzsch, Franziska Klaeger, Sonja Oberbeckmann, Stephanie Mothes, & Matthias Labrenz, Marine Pollution Bulletin, Available online 12 August 2017, In Press, Corrected Proof
Microplastics are widespread in aquatic environments and can be ingested by a wide range of organisms. They can also be transferred along food webs. Estuaries and other tidal wetlands may be particularly prone to this type of pollution due to their particular hydrological characteristics and sewage input, but few studies have compared wetlands with different anthropogenic pressure. Furthermore, there is no information on microplastic transfer to secondary intertidal consumers such as shorebirds.
We analysed intertidal sediments, macroinvertebrates and shorebirds, from three important wetlands along the Eastern Atlantic (Tejo estuary, Portugal; Banc d’Arguin, Mauritania and Bijagós archipelago, Guinea-Bissau), in order to evaluate the prevalence and transfer of microplastics along the intertidal food web. We further investigated variables that could explain the distribution of microplastics within the intertidal areas of the Tejo estuary.
Microfibers were recorded in a large proportion of sediment samples (91%), macroinvertebrates (60%) and shorebird faeces (49%). μ-FTIR analysis indicated only 52% of these microfibers were composed of synthetic polymers (i.e. plastics). Microfiber concentrations were generally higher in the Tejo and lower in the Bijagós, with intermediate values for Banc d’Arguin, thus following a latitudinal gradient. Heavier anthropogenic pressure in the Tejo explains this pattern, but the relatively high concentrations in a pristine site like the Banc d’Arguin demonstrate the spread of pollution in the oceans. Similar microfiber concentrations in faeces of shorebirds with different foraging behaviour and similar composition of fibres collected from invertebrate and faeces suggest shorebirds mainly ingest microfibers through their prey, confirming microfiber transfer along intertidal food webs.
Within the Tejo estuary, concentration of microfibers in the sediment and bivalves were positively related with the percentage of fine sediments and with the population size of the closest township, suggesting that hydrodynamics and local domestic sewage are the main factors influencing the distribution of microfibers.
Pedro M. Lourenço, Catarina Serra-Gonçalves, Joana Lia Ferreira, Teresa Catry, polJose P. Granadeiro, Environmental Pollution, Volume 231, Part 1, December 2017, Pages 123-133
Eight sandy beaches along the coastline of Qatar and four sea surface stations on the eastern coast, adjacent to Doha Bay, were surveyed between December 2014 and March 2015. Microplastics, mainly low density polyethylene and polypropylene, were found in all samples of sediments and seawater. Blue fibers, ranging between 1 and 5 mm, were the dominant type of particle present. Abundances on the sea surface varied between 4.38 × 104 and 1.46 × 106 particles·km− 2, with the highest values being consistently found 10 km offshore, suggesting the presence of a convergence zone. No significant temporal variability was detected for sea surface samples. The concentration of microplastics in intertidal sediments varied between 36 and 228 particles m− 2, with no significant differences among the 8 beaches examined. These results show the pervasiveness of microplastic pollution in coastal environments of the Arabian Gulf. Potential local sources and sinks for microplastics are discussed.
Oyebamiji Abib Abayomi, P. Range, M. A. Al-Ghouti and al., Marine Pollution Bulletin, Volume 124, Issue 1, 15 November 2017, Pages 181-188