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Evaluation of chemicals leached from PET and recycled PET containers into beverages
Reviews on Environmental Health
Abstract
The use of recycled polyethylene terephthalate (rPET) containers, a recent shift in the beverage industry, poses new potential human health concerns including contamination from the original container; use of additives, detergents, and catalysts during recycling; and improper recycling practices. The purpose of this analysis was to evaluate available data regarding: (1) chemicals leached from PET and rPET in bottle form; (2) concentration of these chemicals; and (3) trends between rPET percent and concentration of chemicals leached. This analysis identified 211 scientific articles related to recycled plastic and leachables. Three articles met the inclusion criteria: (1) plastic was in bottle form; (2) plastic was made of PET or rPET; and (3) the study analyzed both PET and rPET using the same methods. This evaluation demonstrated that only nine compounds – benzene, styrene, acetaldehyde, 2-methyl-1,3-dioxolane, furan, bisphenol A (BPA), 2-buta-none, acetone, and limonene – have been studied. Notably, the leachable concentration of benzene, styrene, and BPA increased as the percent of recycled content increased from 0 to 100%. However, 2-methyl-1,3-dioxolane and furan implied a reverse trend, where the leachable concentration decreased as the percent of recycled content increased from 0 to 100%. The concentrations of 2-butanone, acetone, and limonene did not follow any suggested trend. Evidently, recycling PET can lead to changes in the leachables profile. This analysis further identified key areas of research, including testing a variety of liquid types, that need to be addressed to adequately conduct a human health risk assessment.
... Recently, Bezeraj et al. published a comprehensive review that addresses the challenges faced by the mechanical PET recycling industry and emphasizes the importance of quantifying the multi-scale characteristics of the synthesis and recycling of this material [13]. Additionally, other reviews and research articles on the safety of recycled PET for food contact have also been published, with a broader focus [14][15][16][17][18][19]. However, our review aims to specifically focus on the Brazilian market for recycled PET packaging intended for food and beverage contact. ...
Polyethylene terephthalate (PET) is widely used in the food and beverage packaging sector due to its chemical and mechanical properties. Although PET is a fossil-based polymer, its recyclability significantly contributes to reducing the environmental impacts caused by excessive plastic consumption. However, the growing demand for post-consumer recycled PET (PET-PCR) food packaging has raised concerns about the efficiency of decontamination processes involved in recycling this material. This review initially addresses PET synthesis processes, highlighting injection stretch blow molding as the predominant technique for packaging production. It then discusses reverse logistics as a strategy to promote sustainability through the recovery of post-consumer packaging, such as plastic bottles. This review examines mechanical and chemical recycling methods used in PET-PCR production, food safety requirements including positive lists of permitted substances, contaminant migration limits, non-intentionally added substances (NIASs), and updated criteria for the National Health Surveillance Agency (ANVISA) of food-grade PET-PCR resins. Finally, the review explores future prospects for using PET-PCR in the food and beverage packaging sector, assessing its environmental impacts and potential technological advancements to enhance its sustainability and safety.
... For example, Benyathiar et al. (Benyathiar et al., 2022b) reported the fate after use of PET bottles in USA and EU, Gerassimidou et al. (Gerassimidou et al., 2022a) focused only at EU level, Zhang et al. examined the fate of PET in China and Aslani et al. (Aslani et al., 2021a) in Iran. The majority of the data that was published on PET after use is focused on how PET additives affect the environment after their release or mismanagement (Filella, 2020;Hahladakis et al., 2023;Steimel et al., 2024). ...
... These concerns about migration of hazardous chemicals and their impacts on human health are especially relevant for plastic food contact materials (FCMs) made from recycled plastics (Geueke et al., 2018;Cook et al., 2023) because unknown and/or hazardous chemicals can accumulate in recycled material and then migrate into foodstuffs, leading to chronic human exposure, as has been shown in the case of beverage bottles made from polyethylene terephthalate (PET) plastics (Gerassimidou et al., 2022;Steimel et al., 2022;Tsochatzis et al., 2022). Illicit plastic recycling, where non-food grade plastics containing hazardous brominated flame retardants are used to make FCMs, is prevalent, as data from the European, U.S. and Korean markets reveal (Samsonek and Puype, 2013;Rani et al., 2014;Turner, 2018;Paseiro-Cerrato et al., 2021). ...
In the battle against plastic pollution many efforts are being undertaken to reduce, reuse, and recycle plastics. If tackled in the right way, these efforts have the potential to contribute to reducing plastic waste and plastic’s spread in the environment. However, reusing and recycling plastics can also lead to unintended negative impacts, because hazardous chemicals, like endocrine disrupters and carcinogens, can be released during reuse and accumulate during recycling. In this way, plastic reuse and recycling become vectors for spreading chemicals of concern. This is especially concerning when plastics are reused for food packaging, or when food packaging is made with recycled plastics. Therefore, it is of utmost importance that care is taken to avoid hazardous chemicals in plastic food contact materials, and to ensure that plastic packaging that is reused or made with recycled content is safe for human health and the environment. The data presented in this review are obtained from the Database on Migrating and Extractable Food Contact Chemicals (FCCmigex), which is based on over 700 scientific publications on plastic food contact materials. We provide systematic evidence for migrating and extractable food contact chemicals (FCCs) in plastic polymers that are typically reused, such as polyamide (PA), melamine resin (MelRes), polycarbonate (PC), and polypropylene (PP), or that contain recycled content, such as polyethylene terephthalate (PET). 1332 entries in the FCCmigex database refer to the detection of 509 FCCs in repeat-use food contact materials made of plastic. 853 FCCs are found in recycled PET, of which 57.6% have been detected only once. Here, we compile information on the origin, function, and hazards of FCCs that have been frequently detected, such as melamine, 2,4-di-tert-butylphenol, 2,6-di-tert-butylbenzoquinone, caprolactam and PA oligomers, and highlight key knowledge gaps that are relevant for the assessment of chemical safety.
This study examines the presence of bisphenol A (BPA), S (BPS), F (BPF), and M (BPM) in various recycled plastics readily available on the market (LDPE, HDPE, PET, and PP), in light of European Food Safety Authority (EFSA) limits. Twenty samples of different origin are analyzed, cleaning treatments are applied, and the migration potential of these bisphenols into food is studied. BPM is absent in all samples, but a post-consumer recycled LDPE sample reveals high bisphenol concentrations, raising concerns, reaching 8540 ng/g, 370 ng/g, and 29 ng/g of BPA, BPS, and BPF, respectively. Migration tests show substantial migration of these contaminants into food simulants. Using a cleaning treatment with polyethylene glycol (PEG 400) reduces BPA in LDPE, HDPE, PP, and PET samples by 95%, 99%, 97% and 28%, respectively, highlighting the importance of cleaning treatments across various polymers in plastic recycling. These findings not only protect food safety but addressing environmental challenges associated with plastic recycling.
With the European Green Deal, the importance of recycled products and materials has increased. Specifically, for PET bottles, a high content of recycled material (rPET) is demanded by the industry and consumers. This study was carried out in a lab environment replicating real-life industrial processes, to investigate the possible impacts on rPET quality over eleven recycling loops, aiming to use high amounts of rPET repetitively. A cycle included extrusion, solid state polycondensation (SSP), a second extrusion to simulate bottle production, hot wash and a drying step. 75% rPET and 25% virgin PET were extruded in eleven cycles to simulate a recycling and production process. Samples underwent chemical, physical and biological analysis. The quality of the rPET material was not adversely affected. Parameters such as coloring, intrinsic viscosity, concentration of critical chemicals and presence of mutagenic contaminants could be positively assessed. The quality of the produced material was likely influenced by the input material’s high standard. A closed loop PET bottle recycling process using an rPET content of up to 75% was possible when following the proposed process, indicating that this level of recycled content can be maintained indefinitely without compromising quality.
PET beverage bottles have been recycled and safely reprocessed into new food contact packaging applications for over two decades. During recollection of post-consumer PET beverage bottles, PET containers from non-food products are inevitably co-collected and thereby enter the PET recycling feed stream. To explore the impact of this mixing on the safety-in-use of recycled PET (rPET) bottles, we determined the concentrations of post-consumer substances in PET containers used for a range of non-food product applications taken from the market. Based on the chemical nature and amounts of these post-consumer substances, we evaluated their potential carry-over into beverages filled in rPET bottles starting from different fractions of non-food PET in the recollection systems and taking worst-case cleaning efficiencies of super-clean recycling processes into account. On the basis of the Threshold of Toxicological Concern (TTC) concept and Cramer classification tools, we present a risk assessment for potential exposure of the consumer to the identified contaminants as well as unidentified, potentially genotoxic substances in beverages. As a result, a fraction of 5% non-food PET in the recycling feed stream, which is very likely to occur in the usual recollection systems, does not pose any risk to the consumer. Our data show that fractions of up to 20%, which may sporadically be contained in certain, local recollection systems, would also not raise a safety concern.
Polyethylene terephthalate (PET) bottles were produced from three types of recycled PET (rPET) with four levels of recycled content. The migration of substances from these bottles to water was studied. Several migrated substances were detected. The migrated amounts of acetaldehyde and ethylene glycol complied with the limits given in the food contact material (FCM) legislation. Migration of 2‐methyl‐1,3‐dioxolane was below the limit of 10 μg·L−1, which is conventionally applied for non‐intentionally added substances (NIAS) not classified as ‘carcinogenic’, ‘mutagenic’ or ‘toxic to reproduction’ (CMR). Limonene, acetone, butanone and furan were also detected as migrants, of which limonene is a natural fragrant, and the other three are probably residues from solvents used to clean and protect the mould at the small‐scale production facility. Finally, benzene and styrene were also found as migrants from rPET. These migrants appear to originate from heat‐induced reactions within the PET matrix, which involve contaminants. The formation of benzene in rPET is attributed to polyvinylchloride as contaminant. The migrated amounts of benzene from the PET bottles with recycled content to the water simulant are relatively small (0.03–0.44 μg·L−1) after 10 days at 40°C. Consequently, the margin of exposure is 3.105–8.106. Hence, the level of concern for the public health is low, and the migrated amount represents a low priority for risk management. The FCM legislation demands a risk assessment for migrating NIAS. Depending on the underlying data and exposure scenario, different threshold limits in the food can be derived which can still be considered as safe. Non‐intentionally added substances are formed in different amounts in different types of recycled PET and they migrate from PET bottles with recycled content to the contained product.
The majority of post-consumer plastic waste is not recycled. Impediments to the recycling of commodity polymers include separation, impurities and degradation of the macromolecular structures, all of which can negatively affect the properties of recycled materials. An attractive alternative is to transform polymers back into monomers and purify them for repolymerization — a form of chemical recycling we term chemical recycling to monomer (CRM). Material recycled in this way exhibits no loss in properties, creating an ideal, circular polymer economy. This Review presents our vision for realizing a circular polymer economy based on CRM. We examine the energetics of polymerization and other challenges in developing practical and scalable CRM processes. We briefly review attempts to achieve CRM with commodity polymers, including through polyolefin thermolysis and nylon 6 ring-closing depolymerization, and closely examine the recent flourishing of CRM with new-to-the-world polymers. The benefits of heterocycle ring-opening polymerization are discussed in terms of synthetic control and kinetically accessible polymer-backbone functionality. Common chemical and structural characteristics of CRM-compatible ring-opening-polymerization monomers are identified, and the properties, benefits and liabilities of these recyclable polymers are discussed. We conclude with our perspective on the ideals and opportunities for the field.
In the article was presented the results of analysis of the nonconformities which occur during the production of PET bottles in the selected company from Poland. The analysis included six process unit operations of forming PET bottles. The aim of the analysis is to present specific corrective and improvement actions based on the results obtained. The article presents a short description of the process of shaping PET bottles for six selected operations. The block diagram of the PET bottle shaping process is presented. Quality management tools were used for quantitative and qualitative analysis. The use of the Pareto-Lorenz diagram allowed for quantitative an approach to the quality problems of PET bottles. The Ishikawa diagram was used to identify potential causes of the most frequent problem. Corrective actions were proposed to improve the quality of PET bottles tested. The research problem has been solved. As a critical element requiring improvement, the competences of employees and the process of operating machines and devices were indicated.
The extreme durability of polyethylene terephthalate (PET) debris has rendered it a long-term
environmental burden. At the same time, current recycling efforts still lack sustainability. Two
recently discovered bacterial enzymes that specifically degrade PET represent a promising
solution. First, Ideonella sakaiensis PETase, a structurally well-characterized consensus
α/β-hydrolase fold enzyme, converts PET to mono-(2-hydroxyethyl) terephthalate (MHET).
MHETase, the second key enzyme, hydrolyzes MHET to the PET educts terephthalate and
ethylene glycol. Here, we report the crystal structures of active ligand-free MHETase and
MHETase bound to a nonhydrolyzable MHET analog. MHETase, which is reminiscent of
feruloyl esterases, possesses a classic α/β-hydrolase domain and a lid domain conferring
substrate specificity. In the light of structure-based mapping of the active site, activity assays,
mutagenesis studies and a first structure-guided alteration of substrate specificity towards
bis-(2-hydroxyethyl) terephthalate (BHET) reported here, we anticipate MHETase to be a
valuable resource to further advance enzymatic plastic degradation.
Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised their demand 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 determining the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in the 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 recyclate. 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.
This review presents a comprehensive description of the current pathways for recycling of polymers, via both mechanical and chemical recycling. The principles of these recycling pathways are framed against current-day industrial reality, by discussing predominant industrial technologies, design strategies and recycling examples of specific waste streams. Starting with an overview on types of solid plastic waste (SPW) and their origins, the manuscript continues with a discussion on the different valorisation options for SPW. The section on mechanical recycling contains an overview of current sorting technologies, specific challenges for mechanical recycling such as thermo-mechanical or lifetime degradation and the immiscibility of polymer blends. It also includes some industrial examples such as polyethylene terephthalate (PET) recycling, and SPW from post-consumer packaging, end-of-life vehicles or electr(on)ic devices. A separate section is dedicated to the relationship between design and recycling, emphasizing the role of concepts such as Design from Recycling. The section on chemical recycling collects a state-of-the-art on techniques such as chemolysis, pyrolysis, fluid catalytic cracking, hydrogen techniques and gasification. Additionally, this review discusses the main challenges (and some potential remedies) to these recycling strategies and ground them in the relevant polymer science, thus providing an academic angle as well as an applied one.
The aim of this study was to determine the level of phthalate migration from plastic containers to soft drinks and mineral water and to identify a possible relationship between the amount and type of phthalate migration, type of preservative used, and the pH of the sample. The analysis included 45 samples of products packed in containers made from polyethylene terephthalate. The samples were divided into 5 groups: group 1 (N=9), soft drinks preserved with orthophosphoric acid; group 2 (N=14), soft drinks preserved with Na-benzoate; group 3 (N=5), soft drinks preserved with K-sorbate; group 4 (N=8), soft drinks preserved with a combination of Na-benzoate and K-sorbate; and group 5 (N=9), mineral water without preservatives. The samples were analyzed by the method of gas chromatography, with a detection limit of 0.005 mu g/L. The mean pool phthalate level and mean pH value were 91.67 mu g/L and 2.82 +/- 0.30 in group 1; 116.93 mu g/L and 2.75 +/- 0.32 in group 2; 819.40 mu g/L and 2.88 +/- 0.15 in group 3; 542.63 mu g/L and 2.82 +/- 0.54 in group 4; and 20.22 mu g/L and 5.82 +/- 1.26 in group 5, respectively The highest rate of migration to soft drinks was recorded for dimethyl phthalate, ranging from 53.51 to 92.73 %, whereas dibutyl phthalate and diethylhexyl phthalate showed highest rate of migration to the mineral water (56.04 and 43.42 %, respectively). The highest level of phthalate migration from plastic containers to soft drinks was found in the products preserved with K-sorbate. The rate of phthalate migration appears to be influenced also by the drink pH, i.e. the lower the pH value, the greater the phthalate migration. Dimethyl phthalate showed highest migration to preserved drinks as an acidic medium, which might stimulate modification in the composition of plastic containers according to the type and composition of the product. Additional studies in a greater number of samples are needed. Although the phthalate levels measured in these samples pose no risk for human health, it should be borne in mind that the accumulation of small individual amounts taken with time may increase the lifelong phthalate exposure and eventually threaten the exposed person's life.
The recycling of post-consumer PET (POSTC-PET) as a technology is a cross-disciplinary practice with many fields of science involved. These include polymer chemistry and physics, process engineering and manufacturing engineering. This paper presents a concise background of the current state of knowledge with respect to POSTC-PET recycling covering the disciplines mentioned above. In the first section of this paper, a brief background is presented about virgin PET synthesis, thermal transitions, processing and applications. The second section covers the PET recycling process with a focus on contamination and ways to increase the molecular weight of recycled PET (R-PET). It serves as an introduction to Section 3 where the chain extension process is described in detail. In Section 3, the current understanding of chain extenders, chain extension experimentation variables and equipment is reviewed. Reactive extrusion process is described in Section 4 with a special focus on system stability under chain extension conditions. Section 5 covers the effect of chain extension on R-PET thermal transitions and crystallinity. Section 6 presents the injection stretch blow moulding (ISBM) process as a possible application for R-PET with a focus on preform and bottle moulding. The last section gives a description of FT-IR technology to detect bottles’ orientation and conformation changes.
Recent reports suggest that endocrine disruptors may leach into the contents of bottles made from polyethylene terephthalate (PET). PET is the main ingredient in most clear plastic containers used for beverages and condiments worldwide and has previously been generally assumed not to be a source of endocrine disruptors.
I begin by considering evidence that bottles made from PET may leach various phthalates that have been putatively identified as endocrine disruptors. I also consider evidence that leaching of antimony from PET containers may lead to endocrine-disrupting effects.
The contents of the PET bottle, and the temperature at which it is stored, both appear to influence the rate and magnitude of leaching. Endocrine disruptors other than phthalates, specifically antimony, may also contribute to the endocrine-disrupting effect of water from PET containers.
More research is needed in order to clarify the mechanisms whereby beverages and condiments in PET containers may be contaminated by endocrine-disrupting chemicals.
This article explains the history, from 1600 BC to 2008, of materials that are today termed 'plastics'. It includes production volumes and current consumption patterns of five main commodity plastics: polypropylene, polyethylene, polyvinyl chloride, polystyrene and polyethylene terephthalate. The use of additives to modify the properties of these plastics and any associated safety, in use, issues for the resulting polymeric materials are described. A comparison is made with the thermal and barrier properties of other materials to demonstrate the versatility of plastics. Societal benefits for health, safety, energy saving and material conservation are described, and the particular advantages of plastics in society are outlined. Concerns relating to littering and trends in recycling of plastics are also described. Finally, we give predictions for some of the potential applications of plastic over the next 20 years.
Polyethylene terephthalate (PET) is the third most widely diffused polymer exploited in the packaging industry, monopolizing the bottles market for beverages, and covering almost the 16% of the European plastic consumption in the packaging industry. Even if PET primarily derived from fossil sources and remains not-biodegradable in the environment, novel advancements in the field pointed out the possibility of producing PET in a more sustainable way (e.g., from biomasses) or the possibility of biodegrade this polyester through the enzymatic action of specific genetically-modified/isolated bacteria/enzymes. By considering also the high recyclability of PET, and the possibility of potentially indefinitely re-use this material, one can assume that the future of PET is still to be written. Therefore, all aspects involving the industrial production (with traditional and sustainable chemical routes), intrinsic physicochemical/thermal/mechanical properties, undesired degradation phenomena, chemical/mechanical recycling processes, and processability of PET are here critically discussed. A particular emphasis has been dedicated to the role of PET in the packaging industry. The main achievements in the PET processing for food packaging are presented, analyzing advantages and disadvantages of each technology. This document aims at providing a useful instrument that collects past, present, and future of the PET: a well-consolidated material that has been able to renew itself over time.
The recycling network of post-consumer plastic packaging waste (PCPPW) was studied for the Netherlands in 2017 with material flow analysis (MFA) and data reconciliation techniques. In comparison to the previous MFA of the PCPPW recycling network in 2014, the predominant change is the expansion of the collection portfolio from only plastic packages to plastic packages, beverage cartons and metal objects. The analysis shows that the amounts of recycled plastics products (as main washed milled goods) increased from 75 to 103 Gg net and the average polymeric purity of the recycled products remained nearly constant. Furthermore, the rise in the amounts of recycled products was accompanied with a rise in the total amount of rejected materials at cross docking facilities and sorting residues at the sorting facilities. This total amount grew from 19 Gg in 2014 to 70 Gg gross in 2017 and is over-proportional to the rise in recycled products. Hence, there is a clear trade-off between the growth in recycled plastics produced and the growth in rejects and residues. Additionally, since the polymeric purity of the recycled plastics did not significantly improve during the last years, most of the recycled plastics from PCPPW are still only suited for open-loop recycling. Although this recycling system for PCPPW is relatively advanced in Europe, it cannot be considered circular, since the net recycling yield is only 26 ± 2% and the average polymeric purity of the recycled plastics is 90 ± 7%.
This article presents fabric phase sorptive extraction (FPSE) as a simple and effective pre-concentration method for the enrichment of acrylate compounds in different food simulants and subsequent analysis of the extracts by ultra-high-performance liquid chromatography with mass spectrometric detection (UPLC-MS). Acrylate compounds come from acrylic adhesives used commonly for sticking the paper labels on polyethylene terephthalate (PET) bottles and therefore, they may exist in recycled polyethylene terephthalate (rPET). Four acrylates were studied: ethylene glycol dimethacrylate (EGDM), pentaerythritol triacrylate (PETA), triethylene glycol diacrylate (TEGDA) and trimethylolpropane triacrylate (TMPTA). Five different types of FPSE media coated with different sol-gel sorbents were studied and finally sol-gel polyethylene glycol- polypropylene glycol-polyethylene glycol triblock copolymer (PEG-PPG-PEG) coated FPSE media was chosen for its satisfactory results. The optimal conditions affecting the extraction efficiency of compounds were determined in three different food simulants. Statistical evaluation of this method reveals good linearity and precision. Under the optimized conditions, the method provided limits of detection of the compounds in the range of (0.1-1.9 ng g-1, 0.1-1.2 ng g-1, 0.2-2.3 ng g-1) in EtOH 10%, HAc 3% and EtOH 20% and the enrichment factor values (EFs) after applying N2 were in the range of 11.1-25.0, 13.8-26.3, 8.3-21.9, in simulants A, B and C respectively. The optimized method was applied successfully to analyze thirteen types of recycled PET samples. Acrylates were found in some of the samples at ng g-1 levels.
The global consumption of plastic continues to increase, and plastic recycling is highlighted as crucial for saving fossil resources and closing material loops. Plastic can be made from different polymers and contains a variety of substances, added intentionally to enhance the plastic's properties (metals added as fillers, colourants, etc.). Moreover, plastic can be contaminated during use and subsequent waste management. Consequently, if substances and contaminants are not removed during recycling, potentially problematic substances might be recycled with the targeted polymers, hence the need for quantitative data about the nature and presence of these substances in plastic. Samples of selected polymers (PET, PE, PP, PS) were collected from different origins; plastic household waste, flakes/pellets of reprocessed plastic from households and industry, and virgin plastic. Fifteen selected metals (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sb, Ti, Zn) were quantified and the statistical analysis showed that both the polymer and origin influenced the metal concentration. Sb and Zn were potentially related to the production stage of PET and PS, respectively. Household plastic samples (waste and reprocessed) were found to contain significantly higher Al, Pb, Ti and Zn concentrations when compared to virgin samples. Only the concentration of Mn was reduced during washing, suggesting that parts of it was present as physical contamination. While most of the metals were below legal limit values, elevated concentrations in reprocessed plastic from households, aligned with increasing recycling rates, may lead to higher metal concentrations in the future.
Bisphenol A (BPA) is widely recognized being an endocrine disrupter and it is employed in many food packaging applications. Although it is not intended to take part in the manufacture of polyethylene terephthalate (PET) food grade, the presence of BPA in recycled PET should not be neglected. To satisfy the increasing need to ensure “BPA-free” articles, a liquid chromatography-tandem mass spectrometry method was developed. The crucial step in the sample preparation was the total dissolution/reprecipitation of the polymer. The repeatability of the method (RSD%, n = 6) was lower than 7.6%, while HorRat values ranged between 0.3 and 0.5. Limits of detection and quantitation were 1.0 and 3.3 ng g⁻¹, respectively. Recovery ranged from 89 to 107%. The method was applied to 23 samples of virgin and recycled pellets, preforms and bottles. Migration tests were also carried out. Results shown significantly higher levels of BPA in recycled PET.
The endocrine disruptors bisphenol A (BPA) and benzophenone (BFN) could be important ingredients in thermochromic printing inks in significant amounts. Due to patent protection and use of the inks, manufacturers are not obliged to state their precise chemical composition. These substances in increasingly used thermochromic printing inks present a hazard for human health and environment in the case of inappropriate application and waste disposal. In this work we enabled identification of the inks that contain these hazardous substances by developing a new method for the analysis of BPA and BFN in thermochromic printing inks. The method is based on the reversed-phase liquid chromatography (LC) with UV detection at 226 and 254 nm. Ultrasound-assisted sample extraction in methanol was proven to be the most suitable and effective among several other solvents. The method was completely validated with satisfactory results. The specificity of the method was proven by the additional LC–tandem mass spectrometry analysis. A representative group of 15 ink samples from various manufacturers, curing and printing modes was analyzed. BPA was found in three samples with mass fractions of about 2% while BFN was found in two samples with mass fractions of 0.34 and 0.66%.
During storage, acetaldehyde migration from polyethylene terephthalate (PET) bottles can affect the quality of mineral water even in the low µg L(-1) range negatively, as it features a fruity or plastic-like off-flavour. For a sensitive and fast analysis of acetaldehyde in mineral water, a new analysis method by the use of 2,4-dinitrophenylhydrazine (DNPH) derivatisation followed by HPLC-electrospray tandem mass spectrometry (ESI-MS/MS) was developed. Acetaldehyde was directly derivatised in the mineral water sample avoiding extraction and/or pre-concentration steps and then analysed by reversed-phase HPLC-ESI-MS/MS using the multiple reaction monitoring mode (MRM). Along with method development, the optimum molar excess of DNPH in contrast to acetaldehyde was studied for the mineral water matrix, because no specific and robust data was yet available for this critical parameter. Best results were obtained by using a calibration via the derivatisation reaction. Without any analyte enrichment or extraction, a LOD of 0.5 µg L(-1) and a LOQ of 1.9 µg L(-1) were achieved. Using the developed method, mineral water samples packed in PET bottles from Germany were analysed and the correlation between the acetaldehyde concentration and other characteristics of the samples were evaluated illustrating the applicability of the method. Besides a relationship between the bottle size and CO2 content of the mineral water and the acetaldehyde migration, a correlation with acetaldehyde migration and the material composition of the bottle, e.g. recycled PET, was noted. Investigating the light influence on the acetaldehyde migration with a newly developed, reproducible light exposure setup, a significant increase of the acetaldehyde concentration in carbonated mineral water samples was observed.
Polyethylene terephthalate food-product containers made with post-consumer materials have been found contaminated with heavy metals due to the recycling and sorting process. The increased use of recycled plastic flake from international suppliers, and subsequent commingling with electronic waste, has been suspected as the source of the increased levels of heavy metal contamination. In this study, nickel, chromium, cadmium, antimony, and lead were quantified in post-consumer polyethylene terephthalate extruded sheet and thermoformed samples, using inductively coupled plasma-atomic emission spectrometry. Recycled polyethylene terephthalate samples were digested using trace-metal grade hydrochloric, perchloric, and nitric acids. Samples were analyzed per ASTM E1613-04, standard test method for determination of lead by inductively coupled plasma atomic emission spectrometry, flame atomic absorption spectrometry, or graphite furnace atomic absorption spectrometry techniques. Two hundred samples were tested of which 29 were found to be contaminated with heavy metals. Chromium and cadmium were found in all 29 sample replicates. Nickel was found in 96.4% of the sample replicates and when it was found, the concentration averaged 11.59 ppm. Lead was found in 90.4% of the sample replicates and the average concentration was 0.15 ppm. Antimony was found in 97.6% of the sample replicates and concentrations were higher in rigid recycled polyethylene terephthalate containers compared to films. It was noted that the total contamination in all 29 samples was well below the threshold level set for the incidental presence of heavy metals in packaging materials as set forth in California’s Toxics in Packaging Prevention Act of 2006. The percentage of each heavy metal that would actually leach from the plastics to contaminate food products during normal processing, packaging, marketing, and consumer use was not determined in this study.
ABSTRACT The development of a scheme for the safety evaluation of mechanical recycling processes for PET is described. The starting point is the adoption of a threshold of toxicological concern such that migration from the recycled PET should not give rise to a dietary exposure exceeding 0.0025 μg/kg bw/day, the exposure threshold value for chemicals with structural alerts raising concern for potential genotoxicity, below which the risk to human health would be negligible. It is practically impossible to test each and every batch of incoming recovered PET and every production batch of recycled PET for all of the different chemical contaminants that could theoretically arise. Consequently, the principle of the safety evaluation is to measure the cleaning efficiency of a recycling process by using a challenge test with surrogate contaminants. This cleaning efficiency is then applied to reduce a reference contamination level for post consumer PET, conservatively set at 3 mg/kg PET for a contaminant resulting from possible misuse by consumers. The resulting residual concentration of each contaminant in recycled PET is used in conservative migration models to calculate migration levels which are then used along with food consumption data to give estimates of potential dietary exposure. The default scenario, when the recycled PET is intended for general use, is that of an infant weighing 5 kg and consuming every day powdered infant formula reconstituted with 0.75 L of water coming from water bottles manufactured with 100% recycled PET. According to this scenario, it can be derived that the highest concentration of a substance in water that would ensure that the dietary exposure of 0.0025 µg/kg bw/day is not exceeded, is 0.017 μg/kg food. The maximum residual content that would comply with this migration limit depends on molecular weight and is in the range 0.09-0.32 mg/kg PET for the typical surrogate contaminants.
Thermal degradation of plastic wastes offers the possibility of recovering energy and useful chemicals. Polyethylene and polypropylene pyrolysis have been discussed already in previous works (E. Ranzi, M. Dente, T. Faravelli, G. Bozzano, S. Fabini, R. Nava, V. Cozzani, L. Tognotti, J. Anal. Appl. Pyrol., 40–41 (1997) 305–319 and T. Faravelli, G. Bozzano, C. Scassa, M. Perego, S. Fabini, E. Ranzi, M. Dente, J. Anal. Appl. Pyrol., 52 (1999) 87–103). This paper aims to develop a detailed kinetic model of polystyrene thermal degradation. The predictions of overall rates of degradation and volatile product distribution are compared with experimental results obtained by different authors at different pressure and temperature conditions. In order to reduce the computing times required by the numerical integration of the kinetic model, a flexible lumping procedure has also been introduced.
Polyethylene terephthalate (PET) has become the most favourable packaging material world-wide for beverages. The reason for this development is the excellent material properties of the PET material, especially its unbreakability and the very low weight of the bottles compared to glass bottles of the same filling volume. Nowadays, PET bottles are used for softdrinks, mineral water, energy drinks, ice teas as well as for more sensitive beverages like beer, wine and juices. For a long time, however, a bottle-to-bottle recycling of post-consumer PET packaging materials was not possible, because of the lack of knowledge about contamination of packaging polymers during first use or recollection. In addition, the decontamination efficiencies of recycling processes were in most cases unknown. During the last 20 years, PET recollection as well as recycling processes made a huge progress. Today, sophisticated decontamination processes, so-called super-clean recycling processes, are available for PET, which are able to decontaminate post-consumer contaminants to concentration levels of virgin PET materials. In the 1991, the first food contact approval of post-consumer PET in direct food contact applications has been given for post-consumer recycled PET in the USA. Now, 20 years after the first food approval of a PET super-clean recycling process, this article gives an overview over the world-wide progress of the bottle-to-bottle recycling of PET beverage bottles, e.g. the recollection amount of post-consumer PET bottles and the super-clean recycling technologies.
Attempts were made to minimize the amounts of acetaldehyde (AA) and formaldehyde (FA) generated during the processing of PET bottle preforms. Various radical scavengers and chain end capping compounds were added to heated PET samples, and p-aminobenzoic, 3,5-dihydroxybenzoic and 4-hydroxybenzoic acids appeared to be the most efficient stabilizers under static laboratory conditions. They were less active under actual processing. Nevertheless the same trends were observed.
Global environmental management is a critically important issue for the business development towards the 21st century. The focus of effort of recovery and recycling of both industrial material of pre-consumer solid waste and post-consumer solid waste has become more important in recent years. As a case study, the current problem of recycling of PET bottles business in Japan is reviewed. In order to maximize productivity of global environment, the closed system of recycling materials should be re-evaluated and established as new social and industrial systems.Global environmental productivity is defined as the ratio of total output to total consumption of materials and energy. Concepts such as ‘Seaborg’s Closed System’ and ‘Reverse Factories’ should be considered if environmental productivity is to be maximized. To encourage a large market for recovered material, a growing buy recycled movement has emerged. The environmental soundness of products can be enhanced through Total Quality Management (TQM). The environmental recycle laws enacted in 1997–99 in Japan is reviewed to produce plastic packages, which contain post-consumer recycled materials with the required price, performance and quality.© 1999 Society of Chemical Industry
The degradation of poly(ethylene terephthalate) (PET) (as substrate for audio-visual materials, amorphous sheet and bottles) has been studied by both accelerated thermal and photo-ageing methods. The degradation has been considered from the opposing viewpoints of environmental acceleration of degradation and prolongment of archival lifetime. In the former case, samples of both polyester sheet and bottles have been aged in contact with dry and wet soils in dark and light conditions at different temperatures to emulate environmental breakdown. In the latter case, non-processed 35 mm cinematographic film has been aged at various relative humidities and temperatures in contact with film containers (metal can) to emulate archival storage conditions. Results of both accelerated ageing studies indicate that breakdown of PET motion picture film is negligible at 60°C and relatively unaffected by variations in humidity of the surrounding environment, over the time period studied (300 days), due to its high crystallinity (55%). At 70 and 80°C the motion picture film exhibits signs of crosslinking rather than degradation due to the high crystallinity and emulsion inhibiting the diffusion of oxygen into the polymer. The presence of iron from the container has an accelerating effect on the degradation rate of motion picture film material but only at temperatures above 90°C. In contrast, normal amorphous polyester sheet and orientated bottles degrade due to their much lower crystallinity (1 and 30%, respectively) and at higher temperatures (70–90°C) breakdown, as characterized by viscosity and chain scission measurements, is indicative of significant polymer deterioration. Breakdown is enhanced by increasing temperature, increasing relative humidity and UV irradiation. The polyester bottles are more stable than sheet due to a greater degree of orientation in the former case and hence higher degree of crystallinity. Both soil (in the case of amorphous PET sheet and bottles) and metal storage can (in the case of cinematograph film) have a significant effect on stability. At temperatures above the glass transition, i.e. 80°C, differences in rates of degradation up to 45% relative humidity are not significant. Videotapes of various archival histories have also been studied using high resolution light microscopy. White crystalline deposits and surface conglomerates are observed with increasing age and these appear to be consistent with artificial ageing experiments.
A declaration of conformity according to European regulation No. 10/2011 is required to ensure the safety of plastic materials in contact with foodstuffs. This regulation established a positive list of substances that are authorized for use in plastic materials. Some compounds are subject to restrictions and/or specifications according to their toxicological data. Despite this, the analysis of PET reveals some non-intentionally added substances (NIAS) produced by authorized initial reactants and additives. Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures in bottled water have been suggested as the source of these toxicological effects. Furthermore, sample preparation techniques, such as solid-phase extraction (SPE), to extract estrogen-like compounds in bottled water are controversial. It has been suggested that inappropriate extraction methods and sample treatment may result in false-negative or positive responses when testing water extracts in bioassays. There is therefore a need to combine chemical analysis with bioassays to carry out hazard assessments. Formaldehyde, acetaldehyde and antimony are clearly related to migration from PET into water. However, several studies have shown other theoretically unexpected substances in bottled water. The origin of these compounds has not been clearly established (PET container, cap-sealing resins, background contamination, water processing steps, NIAS, recycled PET, etc.). Here, we surveyed toxicological studies on PET-bottled water and chemical compounds that may be present therein. Our literature review shows that contradictory results for PET-bottled water have been reported, and differences can be explained by the wide variety of analytical methods, bioassays and exposure conditions employed.
Microbial-, and chemical-based burden of disease associated with lack of access to safe water continues to primarily impact developing countries. Cost-effective health risk-mitigating measures, such as of solar disinfection applied to microbial-contaminated water stored in plastic bottles have been increasingly tested in developing countries adversely impacted by epidemic water-borne diseases. Public health concerns associated with chemical leaching from water packaging materials led us to investigate the magnitude and variability of antimony (Sb) and bromine (Br) leaching from reused plastic containers (polyethylene terephthalate, PET; and polycarbonate, PC) subject to UV and/or temperature-driven disinfection. The overall objective of this study was to determine the main and interactive effects of temperature, UV exposure duration, and frequency of bottle reuse on the extent of leaching of Sb and Br from plastic bottles into water. Regardless of UV exposure duration, frequency of reuse (up to 27 times) was the major factor that linearly increased Sb leaching from PET bottles at all temperatures tested (13-47 °C). Leached Sb concentrations (∼360 ng L(-1)) from the highly reused (27 times) PET bottles (minimal Sb leaching from PC bottles, <15 ng L(-1)) did not pose a serious risk to human health according to current daily Sb acceptable intake estimates. Leached Br concentrations from both PET and PC containers (up to ∼15 μg L(-1)) did not pose a consumer health risk either, however, no acceptable daily dose estimates exist for oral ingestion of organo-brominated, or other plasticizers/additives compounds if they were to be found in bottled water at much lower concentrations. Additional research on potential leaching of organic chemicals from water packaging materials is deemed necessary under relevant environmental conditions.
Furan is formed during commercial or domestic thermal treatment of food. The initial surveys of furan concentrations in heat-treated foods, published by European and US authorities, revealed the presence of relatively high furan levels in coffee, sauces, and soups. Importantly, furan is consistently found in commercial ready-to-eat baby foods. Furan induces hepatocellular tumors in rats and mice and bile duct tumors in rats with a high incidence. Epidemiological studies are not available. It is assumed that cis-2-butene-1,4-dial, the reactive metabolite of furan, is the causative agent leading to toxicity and carcinogenicity. Based on this data, furan is classified as a possible human carcinogen. The initial exposure estimates revealed a relatively small margin (~2,000) between human exposure and those furan doses, which induce liver tumors in experimental animals. As this may give rise for concern, in this review, the currently available toxicological and mechanistic data of furan are summarized and discussed with regard to its applicability in assessing the risk of furan in human diet.
Studies were undertaken to determine the composition of five different types of post-consumer polyethylene terephthalate (PET) feedstreams to ascertain the relative amounts of food containers and non-food containers. Deposit post-consumer PET feedstreams contained approximately 100% food containers, whereas curbside feedstreams contained from 0.04 to 6% non-food containers. Analysis of the PET containers from the different type feedstreams after the containers were subjected to a commercial PET wash system and after processing with a proprietary decontamination technology was accomplished to determine the levels of compounds in the post-consumer PET after the various stages of processing. Comprehensive thermal desorption/GC/MS, purge and trap GC/MS purge and trap GC quantitation, PET dissolution and extraction GC analysis and PET dissolution HPLC analysis established the types and concentrations of compounds that absorb in the PET from the various types of postconsumer feedstreams. A total of 121 compounds were identified in the five different feedstreams. The concentration of absorbed compounds remaining in the deposit material and the non-food applications material after the commercial wash was 28 and 39mgkg(-1) respectively. Analysis of the feedstreams after subjecting the material to a proprietary decontamination process demonstrated the ability of removing all the absorbed compounds to a level below the level of the threshold of regulation. The safety of sourcing of post-consumer PET from food use applications verses non-food use applications of PET has been established.
Typical contamination and the frequency of misuse of poly(ethylene terephthalate) (PET) bottles are crucial parameters in the risk assessment of post-consumer recycled (PCR) PET intended for bottle-to-bottle recycling for direct food contact applications. Owing to the fact that misuse of PET bottles is a rare event, sustainable knowledge about the average concentration of hazardous compounds in PCR PET is accessible only by the screening of large numbers of samples. In order to establish average levels of contaminants in PET source materials for recycling, PET flakes from commercial washing plants (689 samples), reprocessed pellets (38) and super-clean pellets (217) were collected from 12 European countries between 1997 and 2001. Analysis of these materials by headspace gas chromatography revealed average and maximum levels in PCR PET of 18.6 and 86.0 mg kg-1 for acetaldehyde and 2.9 and 20 mg kg-1 for limonene, respectively. Acetaldehyde and limonene are typical compounds derived from PET itself and from prior PET bottle contents (flavouring components), respectively. Maximum levels in PCR PET of real contaminants such as misuse chemicals like solvents ranged from 1.4 to 2.7 mg kg-1, and statistically were shown to result from 0.03 to 0.04% of recollected PET bottles that had been misused. Based on a principal component analysis of the experimental data, the impact of the recollecting system and the European Union Member State where the post-consumer PET bottles had been collected on the nature and extent of adventitious contaminants was not significant. Under consideration of the cleaning efficiency of super-clean processes as well as migration from the bottle wall into food, it can be concluded that the consumer will be exposed at maximum to levels < 50 ng total misuse chemicals day-1. Therefore, PCR PET materials and articles produced by modern superclean technologies can be considered to be safe in direct food applications in the same way as virgin food-grade PET.
The possibility of using recycled polyethylene terephthalate as a food contact material is being seriously considered, but the potential migration of nonvolatile compounds from it must be assessed to ensure that it is safe to do so. In the study presented here, four samples of recycled PET were each exposed to three food simulants under the harsh extraction conditions stipulated by European legislation regarding migration tests. The nonvolatile compounds that migrated from them were determined by ultra performance liquid chromatography-mass spectrometry using three different cone voltages, and both positive and negative ionization modes. A total of 36 chemical compounds were detected, some of which were identified, including common additives such as N,N'-di-beta-naphthyl-p-phenylenediamine (antioxidant) and 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol (light stabilizer) as well as degradation compounds such as ethylene terephthalate dimers and trimers. In addition, specific migration values of three common components of polyethylene terephthalate (diethylene glycol, terephthalic acid, and isophthalic acid) were determined and found to occur at levels of <1 mg/kg-much lower than the specific migration limits stipulated by European legislation.
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