Polycyclic Aromatic Hydrocarbons (PAHs) and Hopanes in Plastic Resin Pellets as Markers of Oil Pollution via International Pellet Watch Monitoring

Aging affects the mechanical interaction between microplastics and lipid bilayers

Plastic pellets, the pre-production form of many plastic products, undergo oxidation and photodegradation upon exposure to oxygen and sunlight, resulting in visible color changes. This study examines the impact of environmental aging on the mechanical interactions between pellet-derived microplastics and lipid bilayers, a critical component of biological membranes. Polyethylene pellets were collected from La Pineda beach near Tarragona, Spain, and categorized by chemical composition and yellowing index, an indicator of aging. The hydrophilicity of these pellets was assessed using contact angle measurements. Microplastics were produced by grinding and filtering these pellets and subsequently dispersed around a free-standing lipid bilayer within a 3D microfluidic chip to investigate their interactions. Our results reveal that aged microplastics exhibit a significantly increased adhesive interaction with lipid bilayers, leading to greater bilayer stretching. Theoretical modeling indicates a linear relationship between the adhesive interaction and the contact angle of the pellets, reflecting their hydrophilicity. These findings emphasize the increased mechanical impact of aged microplastics on biological membranes, which raises concerns about their potential toxicological effects on living organisms. This study highlights the importance of understanding the interactions between environmentally aged microplastics and biological systems to assess their risks, as these may differ significantly from pristine microplastics often studied under laboratory conditions.

Organic pollutants adsorbed on microplastics: Potential indicators for source appointment of microplastics

Pollution by microplastics (MPs) has caused potential threats to the environment. Understanding the sources of MPs in the environment can help control their emissions and reduce environmental risks. Source apportionment of MPs has been conducted according to the characteristics of MPs themselves (such as types of polymers and morphological characteristics). However, the specificity and resolution of the appointments of sources need to be improved. Organic pollutants adsorbed on MPs can be used as a novel and reliable indicator to identify the source of MPs in the environment. In the present work, the analytical methods of MPs and organic pollutants adsorbed on MPs were critically reviewed, and the occurrence of organic pollutants and factors influencing their adsorption on MPs were discussed. Furthermore, the potential applications of organic pollutants adsorbed on MPs as indicators for determining the sources of MPs were highlighted. The study would help recognize the sources of MPs, which will support efforts aimed at reducing their emissions and further pollution of the ecosystem.

Floating plastics as integrative samplers of organic contaminants of legacy and emerging concern from Western Mediterranean coastal areas

This study investigates the role of floating plastics as integrative samplers of organic contaminants. To this end, plastics items were collected in two Western Mediterranean coastal areas: the Mar Menor lagoon, and the last transect of Ebro river. Floating plastics were identified and characterized by attenuated total reflection Fourier-transform infrared spectrometry. Then, organic contaminants were extracted from plastic items by ultrasonic extraction with methanol, and the concentrations of 168 regulated and emerging contaminants were analysed. These compounds were analysed by stir bar sorptive extraction coupled to gas chromatography-mass spectrometry (GC-MS), except for bisphenol analogues, which were analysed with a ultraperformance liquid chromatography pump coupled to a triple quadrupole mass spectrometer (UHPLC-MS/MS), and pharmaceutical compounds, determined by UPLC coupled to hybrid triple quadrupole-linear ion trap mass spectrometer (UPLC-MS/MS). All the contaminants groups considered were detected in the samples, being particularly relevant the contribution of plastic additives. The most frequently detected contaminants were UV-filters, PAHs, pharmaceuticals and synthetic musks. Apart from plasticizers, the individual contaminants octocrylene, homosalate, galaxolide, salycilic acid and ketoprofen were frequently detected in plastics items. The results pointed out to urban and touristic activities as the main sources of pollution in the coastal areas investigated. The utility of floating plastics as integrative samplers for the detection of organic contaminants in aquatic ecosystems has been demonstrated.

(Micro)Plastics Are Toxic Pollutants

Plastics, including microplastics, have generally been regarded as harmful to organisms because of their physical characteristics. There has recently been a call to understand and regard them as persistent, bioaccumulative, and toxic. This review elaborates on the reasons that microplastics in particular should be considered as "toxic pollutants". This view is supported by research demonstrating that they contain toxic chemicals within their structure and also adsorb additional chemicals, including polychlorinated biphenyls (PCBs), pesticides, metals, and polycyclic aromatic hydrocarbons (PAHs), from the environment. Furthermore, these chemicals can be released into tissues of animals that consume microplastics and can be responsible for the harmful effects observed on biological processes such as development, physiology, gene expression, and behavior. Leachates, weathering, and biofilm play important roles in the interactions between microplastics and biota. Global policy efforts by the United Nations Environmental Assembly via the international legally binding treaty to address global plastic pollution should consider the designation of harmful plastics (e.g., microplastics) with associated hazardous chemicals as toxic pollutants.

Hydrophobic organic contaminants affiliated with polymer-specific microplastics in urban river tributaries and estuaries

Exposure to microplastics (MPs) and hydrophobic organic contaminants (HOCs) combined at high concentrations may induce adverse effects to aquatic organisms in laboratory-scale studies. To determine environmentally relevant concentrations of HOCs in MPs, it is essential to understand the occurrence of MP-affiliated HOCs in the aquatic environment. Here we report the occurrences of HOCs affiliated with polymer-specific floating MPs from 12 tributaries and three estuaries in the Pearl River Delta, South China. Target HOCs include nine synthetic musks (SMs), 14 ultraviolet adsorbents (UVAs), 15 polycyclic aromatic hydrocarbons (PAHs), eight polybrominated diphenyl ethers (PBDEs), and 14 polychlorinated biphenyls (PCBs). Average concentrations of MP-affiliated ∑9SM, ∑14UVA, ∑15PAH, ∑8PBDE, and ∑14PCB were 1790, 5550, 1090, 412, and 107 ng g-1, respectively. The average concentrations of HOCs affiliated with MPs of different polymer types were 9790, 7220, 72,500, and 55,800 ng g-1 for polyethylene (PE), polypropylene, polystyrene, and other MPs, respectively. As the concentration of PE was the highest among all MPs at the average concentration of 0.77 mg m-3, the monthly outflow of PE-affiliated HOCs accounted for the largest proportion (46 %) in the outflow of MP-affiliated HOCs (2.8 g) to the coastal ocean via three estuaries. These results suggest that HOCs were highly concentrated in MPs and varied among different chemicals and polymer types. Due to the differences of polymer characteristics and half-life of affiliated chemicals, future toxicology studies concerning exposure to these combined pollutants may need to specify polymer types and their affiliated chemicals.

Fire and Oil Led to Complex Mixtures of PAHs on Burnt and Unburnt Plastic during the M/V X-Press Pearl Disaster

In May 2021, the M/V X-Press Pearl container ship burned for 2 weeks, leading to the largest maritime spill of resin pellets (nurdles). The disaster was exacerbated by the leakage of other cargo and the ship's underway fuel. This disaster affords the unique opportunity to study a time-stamped, geolocated release of plastic under real-world conditions. Field samples collected from beaches in Sri Lanka nearest to the ship comprised nurdles exposed to heat and combustion, burnt plastic pieces (pyroplastic), and oil-plastic agglomerates (petroplastic). An unresolved question is whether the 1600+ tons of spilled and recovered plastic should be considered hazardous waste. Due to the known formation and toxicity of combustion-derived polycyclic aromatic hydrocarbons (PAHs), we measured 20 parent and 21 alkylated PAHs associated with several types of spilled plastic. The maximum PAH content of the sampled pyroplastic had the greatest amount of PAHs recorded for marine plastic debris (199,000 ng/g). In contrast, the sampled unburnt white nurdles had two orders of magnitude less PAH content. The PAH composition varied between the types of spilled plastic and presented features typical of and conflicting with petrogenic and pyrogenic sources. Nevertheless, specific markers and compositional changes for burning plastics were identified, revealing that the fire was the main source of PAHs. Eight months after the spill, the PAH contents of sampled stray nurdles and pyroplastic were reduced by more than 50%. Due to their PAH content exceeding levels allowable for plastic consumer goods, classifying burnt plastic as hazardous waste may be warranted. Following a largely successful cleanup, we recommend that the Sri Lankans re-evaluate the identification, handling, and disposal of the plastic debris collected from beaches and the potential exposure of responders and the public to PAHs from handling it. The maritime disaster underscores pyroplastic as a type of plastic pollution that has yet to be fully explored, despite the pervasiveness of intentional and unintentional burning of plastic globally.

The Minderoo-Monaco Commission on Plastics and Human Health

Background

Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted.

Goals

The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives.

Report Structure

This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations.

Plastics

Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked.

Plastic Life Cycle

The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic.

Environmental Findings

Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being.

Human Health Findings

Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life.

Economic Findings

Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation.

Social Justice Findings

The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs.

Conclusions

It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals.

Recommendations

To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs.

Summary

This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.

Elucidating the negatively influential and potentially toxic mechanism of single and combined micro-sized polyethylene and petroleum to Chlorella vulgaris at the cellular and molecular levels

Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.

GO/TiO2-Related Nanocomposites as Photocatalysts for Pollutant Removal in Wastewater Treatment

Water pollution has been a prevalent issue globally for some time. Some pollutants are released into the water system without treatment, making the water not suitable for consumption. This problem may lead to more grave problems in the future including the destruction of the ecosystem along with the organisms inhabiting it, and illness and diseases endangering human health. Conventional methods have been implemented to remove hazardous pollutants such as dyes, heavy metals, and oil but are incapable of doing so due to economic restraints and the inability to degrade the pollutants, leading to secondary pollution. Photocatalysis is a more recently applied concept and is proven to be able to completely remove and degrade pollutants into simpler organic compounds. Titanium dioxide (TiO₂) is a fine example of a photocatalyst owing to its cost-effectiveness and superb efficiency. However, issues such as the high recombination rate of photogenerated electrons along with positive holes while being only limited to UV irradiation need to be addressed. Carbonaceous materials such as graphene oxide (GO) can overcome such issues by reducing the recombination rate and providing a platform for adsorption accompanied by photocatalytic degradation of TiO₂. The history and development of the synthesis of GO will be discussed, followed by the methods used for GO/TiO₂ synthesis. The hybrid of GO/TiO₂ as a photocatalyst has received some attention in the application of wastewater treatment due to its efficiency and it being environmentally benign. This review paper thereby aims to identify the origins of different pollutants followed by the sickness they may potentially inflict. Recent findings, including that GO/TiO₂-related nanocomposites can remove pollutants from the water system, and on the photodegradation mechanism for pollutants including aromatic dyes, heavy metal and crude oil, will be briefly discussed in this review. Moreover, several crucial factors that affect the performance of photocatalysis in pollutant removal will be discussed as well. Therefore, this paper presents a critical review of recent achievements in the use of GO/TiO₂-related nanocomposites and photocatalysis for removing various pollutants in wastewater treatment.

Derivatives of Plastics as Potential Carcinogenic Factors: The Current State of Knowledge

Simple Summary

Nowadays, micro- and nanoplastic particles can be found almost everywhere, being especially harmful for humans. Their absorption, primarily via inhalation and digestive routes, might lead to a particularly dangerous accumulation of those substances within the human body. Due to the alarming increase in contamination worldwide and excessive production of plastics and synthetic materials, there is an urgent need to investigate the effects of those substances on human health. So far, it has been observed that nano- and microplastics might be extremely harmful, leading to serious health conditions, such as cancers of various human body systems.

Abstract

Micro- and nanoplatics have been already reported to be potential carcinogenic/mutagenic substances that might cause DNA damage, leading to carcinogenesis. Thus, the effects of micro- and nanoplastics exposure on human health are currently being investigated extensively to establish clear relationships between those substances and health consequences. So far, it has been observed that there exists a definite correlation between exposure to micro- and nanoplastic particles and the onset of several cancers. Therefore, we have conducted research using PubMed, Web of Science, and Scopus databases, searching for all the research papers devoted to cancers that could be potentially related to the subject of exposure to nano- and microplastics. Ultimately, in this paper, we have discussed several cancers, including hepatocellular carcinoma, pancreatic cancer, pancreatic ductal adenocarcinoma, biliary tract cancer, and some endocrine-related cancers.

Divergent Forms of Pyroplastic: Lessons Learned from the M/V X-Press Pearl Ship Fire

In late May 2021, the M/V X-Press Pearl container ship caught fire while anchored 18 km off the coast of Colombo, Sri Lanka and spilled upward of 70 billion pieces of plastic or "nurdles" (∼1680 tons), littering the country's coastline. Exposure to combustion, heat, chemicals, and petroleum products led to an apparent continuum of changes from no obvious effects to pieces consistent with previous reports of melted and burned plastic (pyroplastic) found on beaches. At the middle of this continuum, nurdles were discolored but appeared to retain their prefire morphology, resembling nurdles that had been weathered in the environment. We performed a detailed investigation of the physical and surface properties of discolored nurdles collected on a beach 5 days after the ship caught fire and within 24 h of their arrival onshore. The color was the most striking trait of the plastic: white for nurdles with minimal alteration from the accident, orange for nurdles containing antioxidant degradation products formed by exposure to heat, and gray for partially combusted nurdles. Our color analyses indicate that this fraction of the plastic released from the ship was not a continuum but instead diverged into distinct groups. Fire left the gray nurdles scorched, with entrained particles and pools of melted plastic, and covered in soot, representing partial pyroplastics, a new subtype of pyroplastic. Cross sections showed that the heat- and fire-induced changes were superficial, leaving the surfaces more hydrophilic but the interior relatively untouched. These results provide timely and actionable information to responders to reevaluate cleanup end points, monitor the recurrence of these spilled nurdles, gauge short- and long-term effects of the spilled nurdles to the local ecosystem, and manage the recovery of the spill. These findings underscore partially combusted plastic (pyroplastic) as a type of plastic pollution that has yet to be fully explored despite the frequency at which plastic is burned globally.

Widespread microplastic pollution in mangrove soils of Todos os Santos Bay, northern Brazil

Microplastics have been studied in sediments from coastal and aquatic environments, but contamination of mangrove soils is still relatively unknown in most mangroves around the world. In this study, the presence of microplastics was investigated in six mangrove soils around the Todos Santos Bay (TSB), the largest and most important navigable bay on the Brazilian coast. Samples were collected at three depths (surface, 10 cm, and 30 cm) at three different distances from the lower tidal area. Ten grams of soil were sieved in a 150 μm mesh and centrifuged with ZnCl₂ solution (density of 1.5 kg dm^-3) for the extraction of microplastics. The microplastics were quantified, measured, and described using a systematic photographic method and the ImageJ program. Microplastics were abundant in all samples, with a mean of 10,782 ± 7,671 items kg^-1 (max.: 31,087 items kg^-1, only one sample <2,000 items kg^-1), higher than any other value reported worldwide. The abundances varied among the six mangroves studied, with a predominance of fibers and mean size of 196 μm. Even remote mangroves were highly polluted, reflecting a large dispersion of the pollutants. The abundance did not differ significantly between soil depths, evidencing a continuous input and burial of microplastics in the soil up to 30 cm. The investigation of the source of microplastics and their presence in water and biota is urgent in this Brazilian region, and these results emphasize the need for global actions to protect coastal ecosystems.

Interactions of microplastics and main pollutants and environmental behavior in soils

Microplastics (MPs) are emerging global contaminants, attracting more and more attention because of their difficulty in degradation, extensive and persistent pollution. In freshwater environment, especially in the ocean, they have become a global, public and even political research hotspot. However, the distribution, fate and ecological hazards of MPs in agricultural land and other soils have not been explored fully. Although the occurrence of MPs in different habitats has been reviewed at home and abroad, little attention has been paid to its environmental behavior, ecotoxicology and interaction with biological and chemical pollutants in soil. This review summaries the research progress on the source, accumulation, degradation and migration of MPs in soil, the potential risks of ecological environment and food chain. In order to provide theoretical basis and practical suggestions for related research and regulatory countermeasures, the detection and treatment methods and mechanism of microplastics in soil need to be further explored.

Biomarker responses in zebrafish (Danio rerio) following long-term exposure to microplastic-associated chlorpyrifos and benzo(k)fluoranthene

Continuously increasing plastic production causes a constant accumulation of microplastic particles (MPs) in the aquatic environment, especially in industrialized and urbanized areas with elevated wastewater discharges. This coincides with the release of persistent organic pollutants (polycyclic aromatic hydrocarbons (PAHs), pesticides) entering limnic ecosystems. Although the assessment of potential effects of environmental pollutants sorbed to MPs under chronic exposure scenarios seems vital, data on potential hazards and risk by combined exposure to pollutants and microplastics for aquatic vertebrates is still limited. Therefore, zebrafish (Danio rerio) were exposed over 21 days to the organophosphate insecticide chlorpyrifos (CPF; 10 and 100 ng/L) and the PAH benzo(k)fluoranthene (BkF; 0.78 and 50 µg/L) either dissolved directly in water or sorbed to different MPs (irregular polystyrene, spherical polymethyl methacrylate; ≤ 100 µm), where CPF was sorbed to polystyrene MPs and BkF was sorbed to polymethyl methacrylate MPs. Contaminant sorption to MPs and leaching were documented using GC-EI-MS; potential accumulation was studied in cryosections of the gastrointestinal tract. Enzymatic biomarkers and biotransformation were measured in liver and brain. Overall, exposure to non-contaminated MPs did not induce any adverse effects. Results of fluorescence tracking, CYP1A modulation by BkF as well as changes in acetylcholinesterase activity (AChE) by CPF were less pronounced when contaminants were sorbed to MPs, indicating reduced bioavailability of pollutants. Overall, following exposure to waterborne BkF, only minor amounts of parent BkF and biotransformation products were detected in zebrafish liver. Even high loads of MPs and sorbed contaminants did not induce adverse effects in zebrafish; thus, the potential threat of MPs as vectors for contaminant transfer in limnic ecosystems can be considered limited.

Sorption behaviors of petroleum on micro-sized polyethylene aging for different time in seawater

Microplastics (MPs; <5 mm) and oil pollution have been receiving global attention. To date, the adsorption mechanism of petroleum by MPs is largely unknown. This study investigated the adsorption of petroleum on micro-sized polyethylene (mPE) undergoing aging (days 0, 15, 30, 90 and 180). The petroleum adsorption capacity of mPE was further assessed at varying pH (2, 5, 7.32, 10 and 12), temperature (4, 15, 25, 45 and 65 °C) and in presence of coexisting pollutants (Cu, bisphenol A (BPA) and petroleum). The results indicated that the adsorption capacity of mPE increased with the prolonged aging time and smaller-sized particles, while the adsorption capacity of the 550 and 165 μm mPE undergoing aging increased by 12.7%-50.9% and 22.1%-63.9%, respectively. The adsorption kinetics and isotherm model of mPE on petroleum were well fitted by pseudo-second order, intraparticle diffusion, Freundlich and Langmuir models, showing the sorption behavior was controlled by the diffusion of pores, liquid film diffusion, and surface adsorption. The petroleum adsorption capacity of mPE was predominant affected by surface roughness, specific surface area, hydrophobicity, oxidation functional groups, adsorption sites, hydrogen bonds, while zeta potential and crystallinity may not be the crucial factors. Likewise, temperature and pH may influence the characteristics of petroleum, and further result in a decreasing adsorption capacity of mPE to petroleum. The highest adsorption capacity of mPE to petroleum was reached at pH 7.32 and 25 °C. The coexisting Cu, BPA and petroleum competed for adsorption sites on the surface of mPE. These findings could fundamentally provide new insights for environmental risk assessment of MPs, particularly for the specific location like harbor which is commonly rich in MPs and petroleum simultaneously.

Development and Characterization of Films for Food Application Incorporating Porphyran Extracted from Porphyra dioica

Non-biodegradable plastic is one of the biggest environmental problems of our lifetime and, considering the present societal needs, it will get worse. Consequently, there is an urgent need to develop sustainable and renewable alternatives to plastic, such as plastic-like materials obtained from biodegradable polymers, namely sulfated polysaccharides, considered one of the most viable alternatives. There is also a need to obtain these materials in an environmentally and economically sustainable way. The hereby developed process of obtaining film-forming solutions from semi-refined porphyran (PorphSR) uses a green solvent (hot water) with a high extraction yield of semi-refined porphyran (26.66 ± 0.27%) in a reproducible way and with low levels of contaminants. The obtained semi-refined porphyran showed good antioxidant potential in all tests performed: HPSA (Δ0.066 ± 0.002), DPPH (2.23 ± 0.78%), FRAP (0.420 ± 0.014 eq. ascorbic acid µg mg−1 of extract) and ABTS (20.46 ± 0.90%). After being cast into films, the most notable antioxidant properties were those of the semi-refined porphyran in the DPPH, FRAP and ABTS assays and of the pectin, (PorphSR_PcT and PorphSR_PcT_Gly) in the HPSA assay. Morphologically, the films showed relatively homogeneous and low roughness surfaces. It is concluded that the described method to obtain semi-refined porphyran is feasible and reproducible, and that the developed films, mainly PorfP2_PcT_Gly, proved to be a potential candidate for non-biodegradable plastic substitutes.

Contamination knows no borders: Toxic organic compounds pollute plastics in the biodiversity hotspot of Revillagigedo Archipelago National Park, Mexico

Plastic pollution is ubiquitous and not even remote protected islands are safe from it. Floating debris can adsorb toxic compounds that concentrate on their surface, being available to the animals that ingest them. For this reason, a baseline study of plastic pollution was conducted in the remote Revillagigedo Archipelago, in the Mexican Pacific Ocean. In 47 manta net samples an average of 4.8 plastics/1000m² was found, 73% of the pieces being <5 mm. Polyethylene and polypropylene were the most common polymers found. The chemical analysis of organic pollutants revealed that organochlorine pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls are adsorbed on the plastics collected in the area. Filter feeding megafauna such as humpback whales, manta rays and whale sharks could ingest contaminated micro and macroplastics. Plastics were found also on the beach, where they are available to the ingestion by terrestrial animals, including endemic species endangered to extinction.

Environmental threats induced heavy ecological burdens on the coastal zone of the Bohai Sea, China

The environment of the Bohai Sea is under enormous pressure because of rapid economic and urban development associated with increased population inhabiting the coastal zone. Environmental threats to the coastal ecosystem were analyzed using 2006-2017 statistical/monitoring data from the State Oceanic Administration, China. The results showed that harmful algal blooms occurred a total of 104 times during the period of 2006-2017, for a cumulative area of more than 21,275 km². The main environmental threats came from offshore oil and gas production in the form of hydrocarbon pollution during extraction, as well as from urban wastewater and sewage. Oil pollution, mainly generated from spills, offshore oil platforms and large number of vessels/ports, was found to cause very severe negative impacts on the environment. Another threat is from excessive groundwater exploitation which has resulted in seawater intrusion and soil salinization occurrence in more than 90% of coastal areas around the Bohai Sea. The maximum distance of intrusion by seawater and soil salinization was more than 40 and 32 km inland, respectively. Contamination by terrestrial pollutants was identified as another threat affecting the environment quality of the Bohai Sea. Approximately 840,000 t of pollutants were carried into the sea by major rivers annually for 2010-2017. The standard discharge rate of terrestrial-source sewage outlets did not exceed 50%; however, only 13.12% of sea areas adjacent to sewage outlets (rivers) met the environmental quality requirements for functional marine areas. The results also showed the frequency of storm surges in the Bohai Sea which was 8.83 times per year and the resulting annual direct economic losses reached (RMB) 1.77 billion for 2006-2017. The results highlight the urgent need to implement an ecological management strategy to reduce the heavy ecological burdens in the coastal zone of the Bohai Sea.

Monitoring of polycyclic aromatic hydrocarbons, hopanes, and polychlorinated biphenyls in the Persian Gulf in plastic resin pellets

Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and hopanes were analyzed in plastic resin pellets collected from 19 locations along the Persian Gulf coastline. PCBs were high at locations near industrial areas, where their concentrations (sum of 13 congeners, 54-624 ng/g-pellet) were higher than those in rural coastal towns, which were close to global background levels (<10 ng/g-pellet). PAH concentrations (sum of 27 PAH species) varied from 273 to 15,786 ng/g-pellet and were highest in industrial cities (Bushehr and Bandar Abbas), with a petrogenic signature at most locations, possibly due to the petroleum-based industries, refineries, and tankers. These levels were placed in the extremely polluted category on a global basis. The distribution of hopanes was relatively homogeneous, and their range of concentrations was 8048-59,778 ng/g-pellet. This range had a positive correlation with PAH concentrations. The PAH and hopane results emphasize the ubiquity of petroleum pollution in the Persian Gulf.

Microplastics in African ecosystems: Current knowledge, abundance, associated contaminants, techniques, and research needs

Despite Africa ranking top in mismanaged plastic waste, there is insufficient data on the extent of microplastics and its interaction with other contaminants in its ecosystems. Microplastics pollution has been documented globally, however, specific data from the continent is crucial for accurate risk assessment and to drive policies. We critically reviewed 56 articles from 1987 to 2020 and provide an overview of the current knowledge of the abundance and distribution of microplastics and associated contaminants in African aquatic systems and organisms. Most of the studies were carried out in the marine environment and there is currently no available data on the abundance of microplastic pollution in the African terrestrial environment. We show that across all studies, 5-100% of all sampled aquatic organisms contained microplastics. Concerning high levels of microplastics were reported in fish from Egypt compared to other parts of Africa and the world. Across all persistent organic pollutants sampled in microplastics, hopanes and phthalates were present at high concentrations while sodium and zinc were high relative to other trace metals reported. The most frequently occurring plastics were polyethylene followed by polypropylene and polystyrene. We found that most of the studies relied on visual inspection (52%) > FTIR (38%) > Raman spectroscopy (5%) > Scanning electron microscopy (3%) > Differential scanning calorimetry (2%) for identifying microplastics. Major gaps in sampling and identification techniques which may have overestimated or underestimated the current levels were identified. We discuss other research priorities and recommend solutions to address these issues associated with microplastic pollution in Africa.

Plastics Are an Insignificant Carrier of Riverine Organic Pollutants to the Coastal Oceans

Global rivers act as a dominant transport pathway for land-based plastic debris to the marine environment. Organic pollutants (OPs) affiliated with riverine plastics can also enter the global oceans, but their amounts remain unknown. Microplastic (MP) samples were collected in a one-year sampling event from the surface water of the eight main riverine outlets in the Pearl River Delta (PRD), China, and analyzed for OPs affiliated with MPs, including 16 polycyclic aromatic hydrocarbons (PAHs), eight polybrominated diphenyl ethers (PBDEs), and 14 polychlorinated biphenyls (PCBs). The mean concentrations of MP-affiliated ∑₁₆PAH, ∑₈PBDE, and ∑₁₄PCB were 2010 (range: 25-40,100), 412 (range: 0.84-14,800), and 67.7 (range: 1.86-456) ng g^-1, respectively. Based on these and previous results, the annual riverine outflows of MP-affiliated OPs were 148, 83, and 8.03 g for ∑₁₆PAH, ∑₈PBDE, and ∑₁₄PCB, respectively. Assuming that plastic debris of different sizes contained the same concentrations of the target pollutants as MPs, the mean riverine outflows of plastic-bound ∑₁₆PAH, ∑₈PBDE, and ∑₁₄PCB were 6.75, 3.77, and 0.37 kg year^-1, respectively, which were insignificant compared with the riverine outflows of OPs through riverine water discharge (up to hundred tons per year). Apparently, plastics are an insignificant carrier of riverine OPs to the coastal oceans.

Microplastics in the environment: Interactions with microbes and chemical contaminants

Microplastics (MPs) are contaminants of emerging concern that have gained considerable attention during the last few decades due to their adverse impact on living organisms and the environment. Recent studies have shown their ubiquitous presence in the environment including the atmosphere, soil, and water. Though several reviews have focused on the occurrence of microplastics in different habitats, little attention has been paid to their interaction with biological and chemical pollutants in the environment. This review therefore presents the state of knowledge on the interaction of MPs with chemicals and microbes in different environments. The distribution of MPs, the association of toxic chemicals with MPs, microbial association with MPs and the microbial-induced fate of MPs in the environment are discussed. The biodegradation and bioaccumulation of MPs by and in microbes and its potential impact on the food chain are also reviewed. The mechanisms driving these interactions and how these, in turn, affect living organisms however are not yet fully understood and require further attention.

Microplastic-associated trophic transfer of benzo(k)fluoranthene in a limnic food web: Effects in two freshwater invertebrates (Daphnia magna, Chironomus riparius) and zebrafish (Danio rerio)

The continuously growing plastic production and incomplete recycling processes open manifold entry routes for microplastic particles (MPs) into the environment. Since knowledge on trophic transfer of contaminants sorbed to MPs is still insufficient for freshwater systems, the transfer of the model pollutant benzo(k)fluoranthene (BkF) sorbed to polymethyl methacrylate (PMMA) particles in a limnic food web was investigated: Two freshwater invertebrates (Daphnia magna and Chironomus riparius larvae) were selected and either left untreated, exposed to pristine PMMA, PMMA-associated BkF, or exposed to dissolved BkF (BkF_aq). As second-level consumers, zebrafish (Danio rerio) were fed twice daily with pre-treated invertebrates over two days. Induction of hepatic cytochrome P450 by BkF was determined as 7-ethoxy-O-resorufin deethylase (EROD) activity. Both invertebrate species readily ingested PMMA particles, tracked via fluorescence microscopy and accumulated BkF_aq, measured via GC-MS. Fluorescence signals in gastrointestinal tracts of zebrafish were quantified with confocal laser scanning microscopy (CLSM). The fluorescence signal in gastrointestinal tracts of zebrafish was not altered, whereas, EROD activity was significantly induced when zebrafish were fed with Chironomus riparius, pre-exposed to BkF_aq. Trophic exposure scenarios with BkF sorbed to PMMA did not result in any alterations of investigated endpoints in both invertebrate species and zebrafish compared to controls. Given that BkF amounts were in the low ng-range, as detected by GC-MS, the transport of MP-sorbed BkF to zebrafish was less effective than direct exposure to waterborne BkF_aq, and the potential threat of trophic transfer of substances such as BkF in limnic food webs may have been overestimated.

Sorption behaviors of crude oil on polyethylene microplastics in seawater and digestive tract under simulated real-world conditions

The role of plastic as a vector for bioaccumulation of hydrophobic organic pollutants has been widely studied. However, the interactions between microplastics (MPs) and crude oil, and the transfer kinetics of sorbed oil from ingested MPs into aquatic biota are largely unknown. In this study, interactions between MPs and crude oil in seawater and digestive tract mimic of aquatic biota have been examined. To mimic the living, transportation and cooking conditions of aquatic organisms, sorption and desorption behaviors were investigated under room temperature-bath (25 °C), ice-bath (0∼4 °C) and boiling water-bath (95∼100 °C), and pH was set as 4 and 7 for the simulated gut fluid. The results showed that sorption capacity of polyethylene (PE) MPs for crude oil in seawater was higher than that in intestinal tract, indicating more oil residue in aqueous phase of gut fluid in the present of organic particles. The sorption kinetics models were well fitted to the pseudo-order model, and isotherms models were well fitted to the Freundlich model. In addition, the results demonstrated that temperature played a significant effect on crude oil viscosity, and the sorption capacity under different temperatures was in the order of 25 °C > 95∼100 °C > 0∼4 °C, indicating that more oil was remained in aqueous phase at boiling water-bath and ice-bath. The increment of pH enhances the sorption capacities of PE MPs. Moreover, the desorption experiment has supplemented the current findings from the sorption experiments.

Organic pollutants in sedimentary microplastics from eastern Guangdong: Spatial distribution and source identification

Microplastics have a strong affinity for potentially toxic organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). Since 2005, the International Pellet Watch used plastic pellets to monitor hydrophobic organic contaminants in marine environments. We examined the spatial distribution and sources of 16 PAHs and eight OCPs on microplastics (pellets, fragments, and foam) collected from eastern Guangdong beaches with the goal of evaluating the feasibility of exclusively using pellets in global monitoring of hydrophobic organic contaminants. The ∑PAH and ∑OCP concentrations ranged from 11.2 to 7710 ng g^-1 and 2.2-1970 ng g^-1, respectively. Although inter-site and regional differences were insignificant in fragments and foam, regional differences were observed in ∑OCP concentrations on pellets samples collected at the estuary mouth and the distributary (p < 0.05). No regional difference in ∑PAH concentration on microplastics was observed, except between fragments from the remote beach and those from the distributary (p = 0.015) and the estuary mouth (p = 0.015). The compositional profiles of PAHs revealed that PAHs with 2-4 rings were more dominant than those with >4 rings. Considering low molecular weight PAHs are less hydrophobic and more toxic; the results suggest low molecular weight PAHs may pose a significant risk to marine organisms. This study shows that the International Pellet Watch could offer critical data on source and transport of microplastic-associated OCPs but may overlook critical vehicles of PAHs in coastal environments such as foam.

Biomonitoring of aromatic hydrocarbons in clam Meretrix meretrix from an emerging urbanization area, and implications for human health

Pollution with total petroleum hydrocarbons (TPHs) is a global concern and particularly in coastal environments. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the most toxic components of TPHs and they can also be derived from other sources. Fangcheng Port is considered as a representative emerging coastal city in China, but the status, sources, and hazards to organisms and humans with respect to contamination with PAHs and TPHs are unknown in the coastal regions of this area. Therefore, in this study, we cloned cytochrome P450 family genes (CYP1A1, CYP3A, and CYP4) and heat shock protein 70 gene (HSP70) in the clam Meretrix meretrix as well as optimizing the method for measuring the 7-ethoxyresorufin O-deethylase activity. These molecular indicators and four specific physiological indexes were found to be appropriate biomarkers for indicating the harmful effects of PAHs and TPHs on clams after exposure to the crude oil water-soluble fraction. In field monitoring surveys, we found that the 2- and 3-ring PAHs were dominant in the clams whereas the 4- to 6-ring PAHs were dominant in the sediments at each site. The PAH levels (3.63-12.77 ng/g wet weight) in wild clams were lower, whereas the TPH levels (13.25-70.50 μg/g wet weight) were higher compared with those determined previous in China and elsewhere. The concentrations of PAHs and TPHs in the sediments (19.20-4215.76 ng/g and 3.65-866.40 μg/g dry weight) were moderate compared with those in other global regions. Diagnostic ratio analysis demonstrated that the PAHs were derived mainly from pyrogenic sources. The TPHs may have come primarily from industrial effluents, land and maritime transportation, or fishing activities. The Integrated Biomarker Response version 2 indexes indicated that the clams collected from site S5 exhibited the most harmful effects due to contamination by PAHs and TPHs. Human health risk assessments demonstrated that the risks due to PAHs and TPHs following the consumption of clams can be considered acceptable. Our results suggest that continuous monitoring of contamination by PAHs and TPHs is recommended in this emerging coastal city as well as assessing their human health risks.

PAHs Accumulations in Plant Leaves Around Coal-Fired Power Plant and Identification of their Potential Use as Bioindicators

The purpose of this study was to investigate polycyclic aromatic hydrocarbons (PAHs) accumulation in leaves of different plant species growing in the neighborhood of coal-fired power plant (CPP) and to identify potential bioindicators for PAHs pollution monitoring. The study was performed in 8 sites in the surrounding areas of CPP. PAHs concentrations in leaves of 21 plant species growing within 1 km of CPP ranged from 0.043 to 4.52 µg g^-1. A higher mean concentration of PAHs was found in leaves of perennial herbs and shrubs compared with annual herbs and trees. Herbaceous plants had the highest concentrations of 5-6 rings PAHs, and 4-ring PAHs mainly existed in shrubs. For 2- to 3-rings PAHs, there was no significant difference among herbaceous plants trees and shrubs. Then, four representative plants were further chosen for investigating the effect of CPP on the spatial distribution patterns of PAH compounds. No distinct difference in the level of 2- to 3-rings PAHs was observed on Broussonetia kaempferi Sieb, whereas 4 rings, 5-6 rings, and Σ₁₆PAHs had regional statistical differences. PAHs in Kalimeris indica (L.) Sch.-Bip had significant regional statistical differences. With the change of distance, the concentration of PAHs showed a significant decrease. Taraxacum mongolicum tended to capture the largest amount of both total PAHs and 5- to 6-ring PAHs, especially to BaP. These results could improve scientific evidence for the screening of bioindicators, in particular, T. mongolicum could be a priority.

Indicators of Marine Pollution in the North Pacific Ocean

The complex nature of ocean pollution underscores the utility in identifying and characterizing a limited number of "indicators" that enables scientists and managers to track trends over space and time. This paper introduces a special issue on indicators of marine pollution in the North Pacific Ocean and builds on a scientific session that was held at the North Pacific Marine Science Organization. The special issue highlights studies using a variety of indicators to provide insight into the identification of legacy and emerging contaminants, the ranking of priority pollutants from various sources, and the effects of contaminants on ecosystem health in the North Pacific Ocean. Examples include the use of mussels to illustrate spatial and temporal trends of a number of contaminants following the 2011 tsunami in Japan, the use of molecular marker (linear alkylbenzenes, hopanes, and polycyclic aromatic hydrocarbons) profiles to identify pollution sources, and the use of plastic resin pellets to illustrate spatial trends of petroleum pollution around the world. Stable isotopes were used to strengthen the utility of the Glaucous-winged gull (Larus glaucescens) as an indicator of marine pollution. Examples also demonstrate the development and application of biomarker approaches, including gene transcripts, oxidative stress, estradiol, hatchability, and respiration and swimming behavior abnormalities, as a function of exposure to polychlorinated biphenyls, sulfur-diesel, Pinghu crude oil, galaxolide and antifouling biocides. We provide a brief review of indicators of marine pollution, identify research gaps, and summarize key findings from the articles published within the issue. This special issue represents the first compilation of research pertaining to marine pollution indicators in the North Pacific Ocean and provides guidance to inform mitigation and monitoring efforts of contaminants in the region.