Plastic and Human Health: A Micro Issue? Wright, Stephanie L; Kelly, Frank J
Environmental science & technology,
06/2017, Letnik:
51, Številka:
12
Journal Article
Recenzirano
Microplastics are a pollutant of environmental concern. Their presence in food destined for human consumption and in air samples has been reported. Thus, microplastic exposure via diet or inhalation ...could occur, the human health effects of which are unknown. The current review article draws upon cross-disciplinary scientific literature to discuss and evaluate the potential human health impacts of microplastics and outlines urgent areas for future research. Key literature up to September 2016 relating to accumulation, particle toxicity, and chemical and microbial contaminants was critically examined. Although microplastics and human health is an emerging field, complementary existing fields indicate potential particle, chemical and microbial hazards. If inhaled or ingested, microplastics may accumulate and exert localized particle toxicity by inducing or enhancing an immune response. Chemical toxicity could occur due to the localized leaching of component monomers, endogenous additives, and adsorbed environmental pollutants. Chronic exposure is anticipated to be of greater concern due to the accumulative effect that could occur. This is expected to be dose-dependent, and a robust evidence-base of exposure levels is currently lacking. Although there is potential for microplastics to impact human health, assessing current exposure levels and burdens is key. This information will guide future research into the potential mechanisms of toxicity and hence therein possible health effects.
Particulate matter (PM) is a complex, heterogeneous mixture that changes in time and space. It encompasses many different chemical components and physical characteristics, many of which have been ...cited as potential contributors to toxicity. Each component has multiple sources, and each source generates multiple components. Identifying and quantifying the influences of specific components or source-related mixtures on measures of health-related impacts, especially when particles interact with other co-pollutants, therefore represents one of the most challenging areas of environmental health research. Current knowledge does not allow precise quantification or definitive ranking of the health effects of PM emissions from different sources or of individual PM components and indeed, associations may be the result of multiple components acting on different physiological mechanisms. Some results do suggest a degree of differential toxicity, namely more consistent associations with traffic-related PM emissions, fine and ultrafine particles, specific metals and elemental carbon and a range of serious health effects, including increased morbidity and mortality from cardiovascular and respiratory conditions. A carefully targeted programme of contemporary toxicological and epidemiological research, incorporating more refined approaches (e.g. greater speciation data, more refined modelling techniques, accurate exposure assessment and better definition of individual susceptibility) and optimal collaboration amongst multidisciplinary teams, is now needed to advance our understanding of the relative toxicity of particles from various sources, especially the components and reactions products of traffic. This will facilitate targeted abatement policies, more effective pollution control measures and ultimately, a reduction in the burden of disease attributable to ambient PM pollution.
► Identifying toxic component(s) of particulate matter is a major challenge. ► Evidence suggesting differential toxicity of components and sources are discussed. ► Targeted and contemporary studies are needed to further understand relative toxicity of particles. ► Goals of refined research are abatement policies, pollution control measures and improved health.
Despite past improvements in air quality, very large parts of the population in urban areas breathe air that does not meet European standards let alone the health-based World Health Organisation Air ...Quality Guidelines. Over the last 10 years, there has been a substantial increase in findings that particulate matter (PM) air pollution is not only exerting a greater impact on established health endpoints, but is also associated with a broader number of disease outcomes. Data strongly suggest that effects have no threshold within the studied range of ambient concentrations, can occur at levels close to PM₂.₅ background concentrations and that they follow a mostly linear concentration–response function. Having firmly established this significant public health problem, there has been an enormous effort to identify what it is in ambient PM that affects health and to understand the underlying biological basis of toxicity by identifying mechanistic pathways—information that in turn will inform policy makers how best to legislate for cleaner air. Another intervention in moving towards a healthier environment depends upon the achieving the right public attitude and behaviour by the use of optimal air pollution monitoring, forecasting and reporting that exploits increasingly sophisticated information systems. Improving air quality is a considerable but not an intractable challenge. Translating the correct scientific evidence into bold, realistic and effective policies undisputedly has the potential to reduce air pollution so that it no longer poses a damaging and costly toll on public health.
Biomedical research is a significant contributor to the global carbon footprint. Practices are available that could make a difference; however, there are significant obstacles ahead, including a lack ...of specialist expertise in sustainable research practices.
While the distribution and effects of microplastics (MPs) have been extensively studied in aquatic systems, there exits little information on their occurrence in the terrestrial environment and their ...potential impacts on human health. In the present study, street dust and suspended dust were collected from the city and county of Asaluyeh, Iran. Samples were characterized by various microscopic techniques (fluorescence, polarized light, SEM) in order to quantify and classify MPs and microrubbers (MRs) in the urban and industrial environments that are potentially ingestible or inhalable by humans. In < 5-mm street dust retrieved from 15 sites, there were an average of 900 MPs and 250 MRs per 15 g of sample, with MPs exhibiting a range of colours and sizes (<100 to >1000 μm). Most street dust samples were dominated by spherical and film-like particles and MRs largely made up of different sizes of black fragments and fibrous particulates. Airborne dust collected daily over an eight-day period at two locations revealed the ubiquity of fibrous MPs of sizes ranging from about 2 μm to 100 μm and an abundance of about 1 per m−3. These samples contained small MR fragments whose precise characteristics were more difficult to define. Based on the median concentrations in street dust, estimates of acute exposure through ingestion are about 5 and 15 MP d−1 and 2 and 7 MR d−1 for construction workers and young children, respectively. Quantities of inhalable particulates were more difficult to define but the potential toxicity of MPs and MRs taken in by this route was evaluated from assays performed using particulates isolated from street dusts in the presence of an artificial lung fluid. Both types of particle exhibited oxidative potential, with MPs displaying consumptions of different antioxidants that were comparable with corresponding values for a reference urban particulate dust but lower than those for London ambient particulate matter. Thus, MPs and MRs contribute towards the health impacts of urban and industrial dusts but their precise roles remain unclear and warrant further study.
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•900 MPs and 250 MRs of varying size and shape were present in 15 g street dust.•MPs in air were fibrous but MRs were more difficult to characterise.•Acute exposure estimates via ingestion are 15 MP d−1 and 7 MR d−1 for children.•MPs and MRs exhibit oxidative potential that contributes to the toxicity of urban dust.
Microplastics have been increasingly documented in freshwater ecosystems in recent years, and growing concerns have been raised about their potential environmental health risks. To assess the current ...state of knowledge, with a focus on the UK, a literature review of existing freshwater microplastics studies was conducted. Sampling and analytical methodologies currently used to detect, characterise and quantify microplastics were assessed and microplastic types, sources, occurrence, transport and fate, and microplastic-biota interactions in the UK’s freshwater environments were examined. Just 32% of published microplastics studies in the UK have focused on freshwater environments. These papers cover microplastic contamination of sediments, water and biota via a range of methods, rendering comparisons difficult. However, secondary microplastics are the most common type, and there are point (e.g. effluent) and diffuse (non-point, e.g. sludge) sources. Microplastic transport over a range of spatial scales and with different residence times will be influenced by particle characteristics, external forces (e.g. flow regimes), physical site characteristics (e.g. bottom topography), the degree of biofouling, and anthropogenic activity (e.g. dam release), however, there is a lack of data on this. It is predicted that impacts on biota will mirror that of the marine environment. There are many important gaps in current knowledge; field data on the transport of microplastics from diffuse sources are less available, especially in England. We provide recommendations for future research to further our understanding of microplastics in the environment and their impacts on freshwater biota in the UK.
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•Microplastics have been found in UK freshwater environments.•Secondary microplastics are the predominant type in surface waters and sediments.•Fibers and fragments are predominantly ingested by biota.•Existing information is fragmented, incomplete and biased.•Recommendations for future microplastics research in UK freshwaters are proposed.
Freshwater microplastics is an emerging issue which requires synergized research efforts. With a focus on the UK, this review confirms that secondary is the most common but unregulated type and that some key freshwater bodies are unstudied.
•52 studies investigating mechanisms behind impacts of desert dust on health are reviewed.•Desert dust may be a risk factor for inflammatory and allergic lung diseases.•Adhered chemicals, biological ...and mineralogical components are candidate activators.•Desert dust surface reactions may enhance toxicity of aerosols in urban environments.
Desertification and climate change indicate a future expansion of the global area of dry land and an increase in the risk of drought. Humans may therefore be at an ever-increasing risk of frequent exposure to, and resultant adverse health effects of desert sand dust. This review appraises a total of 52 experimental studies that have sought to identify mechanisms and intermediate endpoints underlying epidemiological evidence of an impact of desert dust on cardiovascular and respiratory health. Toxicological studies, in main using doses that reflect or at least approach real world exposures during a dust event, have demonstrated that virgin sand dust particles and dust storm particles sampled at remote locations away from the source induce inflammatory lung injury and aggravate allergen-induced nasal and pulmonary eosinophilia. Effects are orchestrated by cytokines, chemokines and antigen-specific immunoglobulin potentially via toll-like receptor/myeloid differentiation factor signaling pathways. Findings suggest that in addition to involvement of adhered chemical and biological pollutants, mineralogical components may also be implicated in the pathogenesis of human respiratory disorders during a dust event. Whilst comparisons with urban particulate matter less than 2.5 μm in diameter (PM2.5) suggest that allergic inflammatory responses are greater for microbial element-rich dust- PM2.5, aerosols generated during dust events appear to have a lower oxidative potential compared to combustion-generated PM2.5 sampled during non-dust periods. In vitro findings suggest that the significant amounts of suspended desert dust during storm periods may provide a platform to intermix with chemicals on its surfaces, thereby increasing the bioreactivity of PM2.5 during dust storm episodes, and that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere, enhancing toxicity of aerosols in urban environments. In summary, the experimental research on desert dust on respiratory endpoints go some way in clarifying the mechanistic effects of atmospheric desert dust on the upper and lower human respiratory system. In doing so, they provide support for biological plausibility of epidemiological associations between this particulate air pollutant and events including exacerbation of asthma, hospitalization for respiratory infections and seasonal allergic rhinitis.
Transport solutions for cleaner air Kelly, Frank J.; Zhu, Tong
Science (American Association for the Advancement of Science),
05/2016, Letnik:
352, Številka:
6288
Journal Article
Recenzirano
Odprti dostop
In cities across the globe, road transport remains an important source of air pollutants that are linked with acute and chronic health effects. Decreasing vehicle emissions—while maintaining or ...increasing commuter journeys—remains a major challenge for city administrators. In London, congestion-charging and a citywide low-emission zone failed to bring nitrogen dioxide concentrations under control. n Beijing, controls on the purchase and use of cars have not decreased transport emissions to a sufficient extent. As cities continue to grow, not even zero-emission vehicles are the solution. Moving increasingly large numbers of people efficiently around a city can only be achieved by expanding mass transit systems.
This study examines for the first time the characteristics and human exposure of microplastics (MPs) in settled indoor dust in schools. An average of 195 MPs·g−1 of dust were detected in settled ...indoor composite dust samples from 28 schools in Shiraz. White-transparent microfibres with lengths 500–1000 μm were the most abundant type of MP found among the samples examined. Polyethylene terephthalate and polypropylene MPs were dominant across all types of MP found including microfibres. MPs had generally smooth morphology with sharp or regular edges which could have been released to the environment as primary MPs. Among all sampling sites, higher concentrations of MPs were found in the south and centre of the city. These were areas affected by high population density, high traffic load and high presence of industrial units and workshops. Principal Component Analysis (PCA) showed a positive strong correlation between sampling sites and MP physical characteristics. The PCA plots revealed that MP sheets and fragments were prevalent in sites in the North of Shiraz, whereas microfibres were mainly associated with sites in the South. The levels of MPs in the South of Shiraz were greater than in the rest of the country and the wind direction and topography were found to be important factors affecting the MP distribution observed. Compared to other population groups, elementary school students had relatively high exposure risk to MPs. This study reveals that microfibres are widespread in Shiraz’ schools and pose a high exposure risk to MPs for young students.
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•PET and PP MPs of 500 μm to 1000 μm were dominant in settled school dust.•Higher abundance of microfibres in the South of Shiraz compared to the North.•Higher MP concentration in South Shiraz is in line with wind corridors in the city.•There was greater exposure risk to MP fibres than other MPs in Shiraz schools.
The American Thoracic Society has previously published statements on what constitutes an adverse effect on health of air pollution in 1985 and 2000. We set out to update and broaden these past ...statements that focused primarily on effects on the respiratory system. Since then, many studies have documented effects of air pollution on other organ systems, such as on the cardiovascular and central nervous systems. In addition, many new biomarkers of effects have been developed and applied in air pollution studies.This current report seeks to integrate the latest science into a general framework for interpreting the adversity of the human health effects of air pollution. Rather than trying to provide a catalogue of what is and what is not an adverse effect of air pollution, we propose a set of considerations that can be applied in forming judgments of the adversity of not only currently documented, but also emerging and future effects of air pollution on human health. These considerations are illustrated by the inclusion of examples for different types of health effects of air pollution.
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