Microplastics are ubiquitous across ecosystems, yet the exposure risk to humans is unresolved. Focusing on the American diet, we evaluated the number of microplastic particles in commonly consumed ...

Human Consumption of Microplastics

The accumulation of mismanaged plastic waste (MPW) in the environment is a global growing concern. Knowing with precision where litter is generated is important to target priority areas for the implementation of mitigation policies. In this study, using country-level data on waste management combined with high-resolution distributions and long-term projections of population and the gross domestic product (GDP), we present projections of global MPW generation at ~1 km resolution from now to 2060. We estimated between 60 and 99 million metric tonnes (Mt) of MPW were produced globally in 2015. In a business-as-usual scenario, this figure could triple to 155–265 Mt y−1 by 2060. The future MPW load will continue to be disproportionately high in African and Asian continents even in the future years. However, we show that this growth in plastic waste can be reduced if developing economies significantly invest in waste management infrastructures as their GDP grows in the future and if efforts are made internationally to reduce the fraction of plastic in municipal solid waste. Using our projections, we also demonstrate that the majority of MPW (91%) are transported via watersheds larger than 100 km2 suggesting that rivers are major pathways for plastic litter to the ocean.

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Future scenarios of global plastic waste generation and disposal

Marine microplastic debris: An emerging issue for food security, food safety and human health.

The ubiquity of microplastics in aquatic and terrestrial environments and related ecological impacts have gained global attention. Microplastics have been detected in table salt, drinking water, and air, posing inevitable human exposure risk. However, rigorous analytical methods for detection and characterization of microplastics remain scarce. Knowledge about the potential adverse effects on human health via dietary and respiratory exposures is also limited. To address these issues, we reviewed 46 publications concerning abundances, potential sources, and analytical methods of microplastics in table salt, drinking water, and air. We also summarized probable translocation and accumulation pathways of microplastics within human body. Human body burdens of microplastics through table salt, drinking water, and inhalation were estimated to be (0-7.3)×104, (0-4.7)×103, and (0-3.0)×107 items per person per year, respectively. The intake of microplastics via inhalation, especially via indoor air, was much higher than those via other exposure routes. Moreover, microplastics in the air impose threats to both respiratory and digestive systems through breathing and ingestion. Given the lifetime inevitable exposure to microplastics, we urgently call for a better understanding of the potential hazards of microplastics to human health.

https://findresearcher.sdu.dk:8443/ws/files/168676998/A_Review_of_Microplastics_in_Table_salt_Drinking_Water_and_Air.pdf

A Review of Microplastics in Table Salt, Drinking Water, and Air: Direct Human Exposure

Microplastics in different tissues of fish and prawn from the Musa Estuary, Persian Gulf

Rising demand for minerals and metals, including for use in the technology sector, has led to a resurgence of interest in exploration of mineral resources located on the seabed. Such resources, whether seafloor massive (polymetallic) sulfides around hydrothermal vents, cobalt-rich crusts on the flanks of seamounts or fields of manganese (polymetallic) nodules on the abyssal plains, cannot be considered in isolation of the distinctive, in some cases unique, assemblages of marine species associated with the same habitats and structures. In addition to mineral deposits, there is interest in extracting methane from gas hydrates on continental slopes and rises. Many of the regions identified for future seabed mining are already recognised as vulnerable marine ecosystems. Since its inception in 1982, the International Seabed Authority (ISA), charged with regulating human activities on the deep-sea floor beyond the continental shelf, has issued 27 contracts for mineral exploration, encompassing a combined area of more than 1.4 million km2, and continues to develop rules for commercial mining. At the same time, some seabed mining operations are already taking place within continental shelf areas of nation states, generally at relatively shallow depths, and with others at advanced stages of planning. The first commercial enterprise, expected to target mineral-rich sulfides in deeper waters, at depths between 1,500 and 2,000 metres on the continental shelf of Papua New Guinea, is scheduled to begin early in 2019. In this review, we explore three broad aspects relating to the exploration and exploitation of seabed mineral resources: (1) the current state of development of such activities in areas both within and beyond national jurisdictions, (2) possible environmental impacts both close to and more distant from mining activities and (3) the uncertainties and gaps in scientific knowledge and understanding which render baseline and impact assessments particularly difficult for the deep sea. We also consider whether there are alternative approaches to the management of existing mineral reserves and resources, which may reduce incentives for seabed mining.

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An Overview of Seabed Mining Including the Current State of Development, Environmental Impacts, and Knowledge Gaps

The ingestion of microplastic fragments, spheres, and fibers by marine mollusks, crustaceans, and fish, including a number of commercially important species, appears to be a widespread and pervasive phenomenon. Evidence is also growing for direct impacts of microplastic ingestion on physiology, reproductive success and survival of exposed marine organisms, and transfer through food webs, although the ecological implications are not yet known. Concerns also remain over the capacity for microplastics to act as vectors for harmful chemical pollutants, including plastic additives and persistent organic pollutants, although their contribution must be evaluated alongside other known sources. The potential for humans, as top predators, to consume microplastics as contaminants in seafood is very real, and its implications for health need to be considered. An urgent need also exists to extend the geographical scope of studies of microplastic contamination in seafood species to currently underrepresented areas, and to finalize and adopt standardized methods and quality-assurance protocols for the isolation, identification, and quantification of microplastic contaminants from biological tissues. Such developments would enable more robust investigation of spatial and temporal trends, thereby contributing further evidence as a sound basis for regulatory controls. Despite the existence of considerable uncertainties and unknowns, there is already a compelling case for urgent actions to identify, control, and, where possible, eliminate key sources of both primary and secondary microplastics before they reach the marine environment. Integr Environ Assess Manag 2017;13:516-521. © 2017 SETAC.

Microplastics as contaminants in commercially important seafood species.

-Commercial seabed mining seems imminent, highlighting the urgent need for coherent, effective policy to safeguard the marine environment. -Reconciling seabed mining with the United Nations Sustainable Development Goals will be difficult because minerals extraction will have irreversible consequences that could lead to the loss of habitats, species and ecosystems services. -A dialogue needs to take place around social, cultural, environmental and economic costs and benefits. -Governance of human interactions with the seabed is fragmented and lacks transparency, with a heavy focus on facilitating exploitation rather than ensuring protection. -With high uncertainties and high stakes, we present a critical review of proposed policy options for the regulation of seabed mining activities, recommend actions to improve seabed governance and outline the alternatives to mining fragile deep-sea ecosystems.

Seabed Mining and Approaches to Governance of the Deep Seabed

The extraction of minerals from the seabed of the deep oceans is of increasing interest to investors, mining companies and some coastal states. To date, no commercial-scale deep seabed mining has taken place but there is considerable pressure for minerals mining to become an economic reality, including to supply the projected demand for metals to support a global transition to renewable energy. At the same time, the full environmental impacts of deep seabed mining are difficult to predict but are expected to be highly damaging, both within, and perhaps well beyond, the areas mined. Here, we reflect on the considerable uncertainties that exist in relation to deep seabed mining. In particular, we provide a perspective on: 1) arguments that deep seabed mining is needed to supply minerals for the green energy revolution, using the electric vehicle battery industry as an illustration; 2) risks to biodiversity, ecosystem function and related ecosystem services; and 3) the lack of equitable benefit sharing to the global community now and for future generations. We explore the justification for a global moratorium on deep seabed mining to ensure protection of marine ecosystems, the need to focus on baseline research, and how improved governance of targeted marine regions could be key to the preservation and conservation of the ocean biome.

/pdf/challenging-the-need-for-deep-seabed-mining-from-the-3ouxqrx35x.pdf

Challenging the Need for Deep Seabed Mining From the Perspective of Metal Demand, Biodiversity, Ecosystems Services, and Benefit Sharing

Deep seabed mining operations, if permitted, could present significant risks to ocean ecosystems. Disturbance on any scale is likely to be long lasting and irreversible. Scant research to date has examined the impact that deep sea minerals extraction would have on cetaceans. The Clarion-Clipperton Zone (CCZ) is of particular interest to mining companies aiming to exploit polymetallic nodules. The CCZ, with an average depth of 5,500 m and an area of approximately 11,650,000 km2, is a habitat for cetaceans including baleen (mysticetes) and toothed whales (odontocetes). Of particular concern is anthropogenic noise. If permitted, commercial-scale mining is expected to operate 24-hours a day, at varying depths. The sounds produced from mining operations, including from remotely operated vehicles on the seafloor, overlap with the frequencies at which cetaceans communicate, which can cause auditory masking and behavior change in marine mammals. Cetaceans are already facing numerous stressors, including climate change, and many species are still recovering from centuries of exploitation. We argue the need for urgent research to assess more fully the potential impact of deep seabed mining on cetaceans.

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Kathryn A. Miller

Papers

An Overview of Seabed Mining Including the Current State of Development, Environmental Impacts, and Knowledge Gaps

Microplastics as contaminants in commercially important seafood species.

Seabed Mining and Approaches to Governance of the Deep Seabed

Challenging the Need for Deep Seabed Mining From the Perspective of Metal Demand, Biodiversity, Ecosystems Services, and Benefit Sharing

Urgent assessment needed to evaluate potential impacts on cetaceans from deep seabed mining