Recycled electronic plastic and marine litter

Characterization of pyroplastics from the North Atlantic

This work describes for the first time the presence of pyroplastics in the Canary Islands (Spain). A total of 300 pyroplastics, identified between 2021 and 2024 in three beaches of the island of Tenerife, present mainly grey and dark colors, a mean weight of 6.8 ± 13.4 g and mean dimensions of 34.2 ± 17.0 mm (X), 24.5 ± 12.2 mm (Y) and 14.4 ± 6.4 (Z). A wide variety of encapsulated and semi-encapsulated materials were also found in the pyroplastics matrix, such as rocks, wood, charcoal and unmelted plastic inclusions. Fourier-transform infrared spectroscopy analysis revealed that polyethylene and polypropylene were the main types of plastic found, 61.3 % and 33.6 %, respectively. However, an important number of pyroplastics composed of more than one polymer were also found, coexisting even mixtures of polyester and polyethylene or polyethylene and styrene-ethylene-butylene-styrene in the same matrix. X-ray fluorescence spectroscopy analysis revealed the presence of a wide range of elements, being remarkable the high concentration of some heavy metals such as Pb and Cr, registering mean concentration values of 205.3 ± 6.3 mg·kg-1 and 51.1 ± 8.9 mg·kg-1, respectively. A good correlation was also found for these two metals in a total of 22 pyroplastics, which could be indicative of the presence of PbCrO4 as additive, widely used in the plastic industry for its bright yellow color, but currently regulated and restricted due to its harmful effects on human and environment health. Also noteworthy is the large variety of remains of marine organisms identified attached to the surface of the pyroplastics, such as algae, bryozoans, arthropods and molluscs, among others, which could indicate that these formations may act as a transport vector for such marine organisms.

Assessing Microplastics and Nanoparticles in the Surface Seawater of Venice Lagoon-Part I: Methodology of Research

Microplastics (MPs) and nanoplastics (NPs) both represent significant concerns in environmental sciences. This paper aims to develop a convenient and efficient methodology for the detection and measurement of MPs and nanoparticles from surface seawater and to apply it to the water samples collected from the UNESCO site of Venice and its lagoon, more precisely in the Venice-Lido Port Inlet, Grand Canal under Rialto Bridge, and Saint Marc basin. In this study, MPs were analyzed through optical microscopy for their relative abundance and characterized based on their color, shape, and size classes, while the concentration and the mean of nanoparticles were estimated via the Nanoparticle Tracking Analysis technique. Bulk seawater sampling, combined with filtration through a cascade of stainless-steel sieves and subsequent digestion, facilitates the detection of MPs of relatively small sizes (size classes distribution: >1 mm, 1000-250 μm, 250-125 μm, 125-90 μm, and 90-32 μm), similar to the size of MPs ingested by marine invertebrates and fishes. A protocol for minimizing interference from non-plastic nanoparticles through evaporation, digestion, and filtration processes was proposed to enrich the sample for NPs. The findings contribute to the understanding of the extent and characteristics of MPs and nanoparticle pollution in the Venice Lagoon seawater, highlighting the potential environmental risks associated with these pollutants and the need for coordinated approaches to mitigate them. This article is based on scientific research carried out within the framework of the H2020 In-No-Plastic-Innovative approaches towards prevention, removal and reuse of marine plastic litter project (G.A. ID no. 101000612).

Metal(oid)s in plastic debris, with distinct features, from Spanish Mediterranean beaches with different anthropogenic pressure: Are these particles potential monitors for metal pollution?

Metal(oid)s concentrations have been quantified in plastic pieces collected from four beaches located in the Mediterranean coast of Spain with different characteristics (i.e. anthropogenic pressure, zone). Metal(oid)s content was also related to selected plastic criteria (i.e. color, degradation status, polymer). The selected elements were quantified with mean concentrations in the sampled plastics with the following order: Fe > Mg > Zn > Mn > Pb > Sr > As > Cu > Cr > Ni > Cd > Co. Moreover, black, brown, PUR, PS, and coastal line plastics concentrated the higher metal(oid)s levels. Local of sampling (influence of mining exploitation) and severe degradation were key factors for uptake of metal(oid)s from water by plastics as modification of surfaces strengths their adsorption capacity. Determined high levels of Fe, Pb and Zn in plastics reflected the pollution degree of the marine areas. Therefore, this study is a contribution for the potential use of plastics as pollution monitors.

Metal leaching from plastics in the marine environment: An ignored role of biofilm

A large quantity of metal compounds in plastics are released into the marine environment every year. However, our understanding of the extent and mechanism by which polymer-bound metals leach into seawater is still limited. In this study, a comprehensive survey was conducted to measure the metal concentrations in commonly used plastics and evaluate the effects of environmental factors (temperature, radiation, and salinity) and the physiochemical properties (surface roughness, specific surface area, hydrophobicity, and crystallinity) of the plastics on their metal leaching into seawater. In particular, we observed the metal loss from six plastics submerged in coastal seawater for eight months and studied the role of biofilm in controlling the leaching of Sb, Sn, Pb, Ba, and Cr. Our results indicate that increased temperature enhanced the release of these metals, while exposure to ultraviolet radiation significantly increased the leaching of Sn from polylactide (PLA). High salinity facilitated the leaching of Sn from PLA and Pb from polyvinylchloride ball, however inhibited the leaching of Ba from PE wrap. The leaching rate was primarily determined by the inherent property of crystallinity. Metal loss from the plastics in the field was apparent during the first three weeks, but then was hindered by the development of biofilm. Our study provides the mechanisms underlying metal leaching from physical, chemical, and biological perspectives, which is useful for understanding the environmental risk of the plastic-containing metals.

PBDEs in the marine environment: Sources, pathways and the role of microplastics

Brominated flame retardants (BFRs) are an important group of additives in plastics that increase resistance to ignition and slow down the rate of burning. Because of concerns about their environmental and human health impacts, however, some of the most widely employed BFRs, including hexabromocyclododecane (HBCD) and commercial mixtures of penta-, octa- and deca- (poly)bromodiphenyl ethers (PBDEs), have been restricted or phased out. In this review, the oceanic sources and pathways of PBDEs, the most widely used BFRs, are evaluated and quantified, with particular focus on emissions due to migration from plastics into the atmosphere versus emissions associated with the input of retarded or contaminated plastics themselves. Calculations based on available measurements of PBDEs in the environment suggest that 3.5 and 135 tonnes of PBDEs are annually deposited in the ocean when scavenged by aerosols and through air-water gas exchange, respectively, with rivers contributing a further ∼40 tonnes. Calculations based on PBDE migration from plastic products in use or awaiting or undergoing disposal yield similar net inputs to the ocean but indicate a relatively rapid decline over the next two decades in association with the reduction in the production and recycling of these chemicals. Estimates associated with the input of PBDEs to the ocean when "bound" to marine plastics and microplastics range from about 360 to 950 tonnes per year based on the annual production of plastics and PBDEs over the past decade, and from about 20 to 50 tonnes per annum based on the abundance and distribution of PBDEs in marine plastic litter. Because of the persistence and pervasiveness of plastics in the ocean and diffusion coefficients for PBDEs on the order of 10^-20 to 10^-27 m² s^-1, microplastics are likely to act as a long-term source of these chemicals though gradual migration. Locally, however, and more important from an ecotoxicological perspective, PBDE migration may be significantly enhanced when physically and chemically weathered microplastics are exposed to the oily digestive fluids conditions of fish and seabirds.

Analytical and reclamation technologies for identification and recycling of precious materials from waste computer and mobile phones

Waste electrical and electronic equipment (WEEE) is one of the world's fastest-growing class of waste. WEEE contain a large amount of precious materials that have aroused the interest to develop new recycling technologies. Hence, effective recycling strategies are extremely necessary to promote the proper handling of these materials as well as for environmentally sound recovery of secondary raw resource. This paper reviews important existing methods and emerging technologies in WEEE management, with special emphasis in characterization, extraction and reclamation of precious materials from waste computer and mobile phones. Traditional pyrometallurgical and hydrometallurgical technologies still play a central role in the recovery of metals. More recently, emerging greener recycling technologies using microorganisms (i.e. biometallurgical), plasma arc fusion method and pretreatments (i.e. ultrasound and mechanochemical technologies) combined with other recycling methods (e.g. hydrometallurgical), and using less toxic solvents such as ionic liquids (ILs) and deep eutectic solvents (DESs) have also been attempted to recycle metals from computer and mobile phone scrap. The role of analytical method development, especially using spectroanalytical methods for chemical inspection and e-waste sorting process at industrial applications is also discussed. This confirmed that most direct sampling techniques such as laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XFR) have several advantages over traditional sorting methods including rapid analytical response, without use of chemical reagents or waste generation, and greater reclamation of precious and critical materials in the WEEE stream.

Hazardous metal additives in plastics and their environmental impacts

Historically, many additives and catalysts used in plastics were based on compounds of toxic metals (and metalloids), like arsenic, cadmium, chromium(VI), and lead. Despite subsequent restrictions, hazardous additives remain in plastics in societal circulation because of the pervasiveness of many products and the more general contamination of recycled goods. However, little is understood about their presence and impacts in the environment, with most studies focusing on the role of plastics in acquiring metals from their surroundings through, for example, adsorption. Accordingly, this paper provides a review of the uses of hazardous, metal-based additives in plastics, the relevant European regulations that have been introduced to restrict or prohibit usage in various sectors, and the likely environmental impacts of hazardous additives once plastics are lost in nature. Examination of the literature reveals widespread occurrence of hazardous metals in environmental plastics, with impacts ranging from contamination of the waste stream to increasing the density and settling rates of material in aquatic systems. A potential concern from an ecotoxicological perspective is the diffusion of metals from the matrix of micro- and nanoplastics under certain physico-chemical conditions, and especially favorable here are the acidic environments encountered in the digestive tract of many animals (birds, fish, mammals) that inadvertently consume plastics. For instance, in vitro studies have shown that the mobilization of Cd and Pb from historical microplastics can greatly exceed concentrations deemed to be safe according to migration limits specified by the current European Toy Safety Directive (17 mg kg^-1 and 23 mg kg^-1, respectively). When compared with concentrations of metals typically adsorbed to plastics from the environment, the risks from pervasive, historical additives are far more significant.

Leaching and extraction of additives from plastic pollution to inform environmental risk: A multidisciplinary review of analytical approaches

Plastic pollution is prevalent worldwide and has been highlighted as an issue of global concern due to its harmful impacts on wildlife. The extent and mechanism by which plastic pollution effects organisms is poorly understood, especially for microplastics. One proposed mechanism by which plastics may exert a harmful effect is through the leaching of additives. To determine the risk to wildlife, the chemical identity and exposure to additives must be established. However, there are few reports with disparate experimental approaches. In contrast, a breadth of knowledge on additive release from plastics is held within the food, pharmaceutical and medical, construction, and waste management industries. This includes standardised methods to perform migration, extraction, and leaching studies. This review provides an overview of the approaches and methods used to characterise additives and their leaching behaviour from plastic pollution. The limitations of these methods are highlighted and compared with industry standardised approaches. Furthermore, an overview of the analytical strategies for the identification and quantification of additives is presented. This work provides a basis for refining current leaching approaches and analytical methods with a view towards understanding the risk of plastic pollution.

PAH and POP Presence in Plastic Waste and Recyclates: State of the Art

The presence of different pollutants in recycled plastics is reviewed in this article. The desirable circular economy of plastics should be linked to the availability of clean recycled plastics with a non-significant and small to nil amount of substances of concern. Different researchers found polycyclic aromatic hydrocarbons (PAHs) and Persistent Organic Pollutants (POPs), such as brominated flame retardants (BFRs), pesticides, dioxins and furans (PCDD/Fs and PBDD/Fs) in plastic recyclates. This represents an added difficulty to the effective recycling process of plastics that reduces the demand for energy and materials, in addition to posing a great environmental danger since they represent a vector of accumulation of the contaminants that will finally appear in the most unexpected products. Life Cycle Analysis of the plastic wastes recycling process indicates a great saving of energy, water and CO2 emissions.

Mobilisation kinetics of Br, Cd, Cr, Hg, Pb and Sb in microplastics exposed to simulated, dietary-adapted digestive conditions of seabirds

Samples of beached plastics and historical and contemporary consumer plastics containing hazardous elements derived from reaction residues or functional additives have been micronised and subject to extraction conditions representative of the digestive environment of seabirds. Mobilisation of Br, Cd, Cr, Hg, Pb and Sb into NaCl solution, an avian physiologically-based extraction test (PBET) and a dietary-adapted PBET (DA-PBET) incorporating fish oil as part of the avian diet was monitored by ICP-MS over a 168-h period. Kinetic data were subsequently fitted using pseudo-first-order and parabolic diffusion models in order to derive rate constants for the release of hazardous elements during avian digestion of microplastics. Rate constants were variable and dependent on the nature and origin of plastic, type of residue or additive, extractant solution employed and model applied. Resulting estimates of bioaccessibility, defined as the equilibrium or maximum concentration of an element mobilised over the time course relative to its total concentration, were variable but considerable in many cases. Specifically, maximum values of about 65% of Cd and 100% of Pb were observed in consumer polycarbonate-acrylonitrile butadiene styrene exposed to the avian PBET and beached polyurethane exposed to the DA-PBET, respectively. The potential health risks of hazardous elements in microplastics are addressed and criteria for classification based on the European Toy Safety Directive migration (mobilisation) limits are proposed.

Mobilisation of antimony from microplastics added to coastal sediment

Antimony (Sb) widely occurs in plastics as a pigment and reaction residue and through the use and recycling of electronic material enriched in Sb as a flame retardant synergist. In this study, clean estuarine sediment has been contaminated by different microplastics prepared from pre-characterised samples of different types of plastic (including a rubber) containing a range of Sb concentrations (256-47,600 μg g^-1). Sediment-plastic mixtures in a mass ratio of 100:1 were subject to 6-h extractions in seawater and in seawater solutions of a protein (bovine serum albumin; BSA) and a surfactant (taurocholic acid; TA) that mimic the digestive conditions of coastal deposit-feeding invertebrates. Most time-courses for Sb mobilisation could be defined by a second-order diffusion equation, with rate constants ranging from 44.6 to 0.0216 (μg g^-1)^-1 min^-1. Bioaccessibilities, defined as maximum extractable concentrations throughout each time course relative to total Sb content, ranged from <0.01% for a polycarbonate impregnated with Sb as a synergist exposed to all solutions, to >1% for acrylonitrile butadiene styrene containing a Sb-based colour pigment exposed to solutions of BSA and TA and recycled industrial polyethylene exposed to BSA solution. The potential for Sb to bioaccumulate or elicit a toxic effect is unknown but it is predicted that communities of deposit-feeders could mobilise significant quantities of Sb in sediment contaminated by microplastics through bioturbation and digestion.

The influence of additives on the fate of plastics in the marine environment, exemplified with barium sulphate

With an inherent density marginally below that of seawater, polyolefins (polyethylene-polypropylene) are predicted to float or undergo beaching in the marine environment. Polyolefins commonly observed on the seabed, therefore, require additional considerations that are usually based around increasing density through fouling or packaging into sinking faecal matter. Here, however, we propose that the presence of additives is of least equal significance to the behaviour of such plastics in marine systems. We compared barium, present largely as the filler, BaSO₄ (density = 4.5 g cm^-3), in consumer and beached plastics and established that the metal was more abundant and occurred at higher concentrations in the former samples, consistent with the environmental fractionation of plastics based on additive content. Significantly, the Ba content of polyolefins required to confer a density above seawater is about 13,000 mg kg^-1, a value that was exceeded in many consumer plastics but never observed in beached samples.

Pb(II) uptake onto nylon microplastics: Interaction mechanism and adsorption performance

Both heavy metals and microplastic pollutants are ubiquitous in the aquatic environment. The uptake of lead(II) ions from aqueous solutions onto aged nylon microplastics was investigated as a function of pH, contact time, temperature, supporting electrolyte concentration and fulvic acid concentration in batch studies. The effect of surface properties on the adsorption behavior of lead(II) was investigated with scanning electron microscope equipped with the energy dispersive X-ray spectroscope (SEM-EDAX), Fourier transform-infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and differential scanning calorimetric (DSC). The adsorption kinetics conformed to the pseudo-second order equation, Elovich equation and intraparticle diffusion model well. The experimental data of the adsorption process was fitted to the Langmuir and Freundlich adsorption isotherms and the parameters were estimated. The lead(II) uptake on aged nylon microplastics was spontaneous and endothermic in nature. The lead(II) adsorption was significantly dependent on the sodium chloride concentrations, initial solution pH and fulvic acid concentrations. Results of this study highlight the importance of surface carboxyl function group of aged nylon microplastics in controlling lead(II) adsorption.