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 foods in relation to their recommended daily intake. The potential for microplastic inhalation and how the source of drinking water may affect microplastic consumption were also explored. Our analysis used 402 data points from 26 studies, which represents over 3600 processed samples. Evaluating approximately 15% of Americans’ caloric intake, we estimate that annual microplastics consumption ranges from 39000 to 52000 particles depending on age and sex. These estimates increase to 74000 and 121000 when inhalation is considered. Additionally, individuals who meet their recommended water intake through only bottled sources may be ingesting an additional 90000 microplastics annually, compared to 4000 microplastics for those who consume only tap water. These estimates are subject to large amounts of variation; however, given methodological and data limitations, these values are likely underestimates.

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Microplastics (MPs) contamination in marine environments is of increasing concern, as plastic particles are globally ubiquitous across ecosystems. A large variety of aquatic taxa ingest MPs, but the extent to which animals accumulate and transfer MPs through food webs is largely unknown. In this study, we quantified MP uptake in bivalves, crabs, echinoderms, and fish feeding at different trophic levels at three sites on southern Vancouver Island. We paired stable-isotope food web analysis with MP concentrations in digestive tracts across all trophic levels and in fish livers. We then used Bayesian generalized linear mixed models to explore whether bioaccumulation and biomagnification were occurring. Our results showed that MPs (100-5000 μm along their longest dimension) are not biomagnifying in marine coastal food webs, with no correlation between the digestive tract or fish liver MP concentrations and trophic position of the various species. Ecological traits did, however, affect microplastic accumulation in digestive tracts, with suspension feeder and smaller-bodied planktivorous fish ingesting more MPs by body weight. Trophic transfer occurred between prey and predator for rockfish, but higher concentrations in full stomachs compared with empty ones suggested rapid excretion of ingested MPs. Collectively, our findings suggested the movement of MP through marine food webs is facilitated by species-specific mechanisms, with contamination susceptibility a function of species biology, not trophic position. Furthermore, the statistical methods we employ, including machine learning for classifying unknown particles and a probabilistic way to account for background contamination, are universally applicable to the study of microplastics. Our findings advance understanding of how MPs enter and move through aquatic food webs, suggesting that lower-trophic-level animals are more at risk of ingesting >100-μm MPs, relative to higher-trophic-level animals. Our work also highlights the need to advance the study of <100-μm

Metrics & MoreArticle RecommendationsWe discovered an error in Table 1. The error influenced only adult male and female total annual microplastic intake. Total annual microplastic intake estimates for male and female children were not influenced by this error. Daily consumption and inhalation, annual consumption and inhalation, and total daily intake estimates for adults and children were not affected. This error was attributed to alcohol intake being included as the recommended alcohol consumption value (adult males 0.71 L/day and adult females 0.35 L/day) when calculating total annual intake, as opposed to the per capita alcohol consumption value (adult males 0.04 L/day and adult females 0.01 L/day) that was included in the rest of the analysis, Figure 1 and 2, and supplemental tables. The total annual intake of microplastics for adult males and females is 113 743 and 94 283, respectively. We had previously reported 121 664, and 98 305 for adult males and females, respectively. A revised version of Table 1 and corrected statements are below. None of the conclusions discussed in the manuscript are affected by the correction. We apologize for any inconvenience caused. Please find the correct concentrations stated below:• Abstract: These estimates increase to 74 000 and 113 000 when inhalation is considered. • Page 7071: The combination of ingestion and inhalation of MPs yields total annual exposure estimates of approximately 81 000, 113 000, 74 000, and 94 000 for male children, male adults, female children, and female adults, respectively (Table 1).• Page 7072: Our findings indicate that American adults and children consuming the recommended or average amounts of the items that have been analyzed for MPs to date are exposed to between 74 000 and 113 000 MPs per year.

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Little is known about the effect of the COVID-19 pandemic on recreational fisheries compliance. Starting in 2015, we monitored recreational fishing activity in Rockfish Conservation Areas (RCAs) with trail cameras overlooking RCAs around Galiano Island, Canada. We also carried out in-person surveys with recreational fishers at marinas and docks to assess recreational fisher compliance with RCAs. Questions included asking fishers whether they had accidentally or intentionally fished inside RCAs with prohibited techniques in the past two years. The number of suspected or confirmed angling incidents that we observed on the trail cameras declined steadily from 2015 to 2019, and then increased significantly during the pandemic to the highest levels seen during our eight years of data collection. The number of fishers who admitted to intentionally or accidentally fishing in RCAs in the past two years with prohibited gears did not change during the pandemic, although there was an apparent but not statistically significant increase in the number of respondents who personally knew someone who intentionally fished in RCAs. Our study corroborates other research that showed a response of pandemic lockdowns on illegal activities. High non-compliance highlights the ongoing need for education, outreach, and increased enforcement.

Spatial subsidies are associated with pronounced ecosystem responses, as nutrients cross ecological boundaries and cascade through food webs. While the importance of subsidies is known, the role of shellfish, specifically molluscs, as a marine subsidy has not been formally described. Focusing primarily on the Pacific coast of North America, we identify vectors that transport shellfish-derived nutrients into coastal terrestrial environments, including birds, mammals, and over 13 000 yr of marine resource use by people. Evidence from recipient ecosystems suggests shellfish drastically influence soil chemistry, forest productivity and the diversity of primary producers at the regional and landscape level. Responses in higher trophic levels have not yet been investigated, but given documented responses in lower trophic levels, this may be due to a lack of examination. To determine if the processes we describe within the northeast Pacific are pertinent to coastal environments worldwide, we also explore shellfish subsidies globally, with a specific focus on temperate and tropical islands. As shellfish are not as spatially or temporally constrained as other subsidies, our examination suggests our findings are applicable to many other geographical regions along the marine-terrestrial interface. Marine subsidiesMarine subsidies occur when nutrients are transferred from marine to terrestrial ecosystems, anywhere along the 594 000 km of global coastline (Hammond 1990). These subsidies can take the form of seabird guano (Sánchez-Piñero and Polis 2000), marine mammal carcasses (Polis and Hurd 1996), spawning fishes (Fox et al. 2015, Reimchen 2018 or macroalgae deposition (Spiller et al. 2010). While all of these subsidies play important roles in shaping terrestrial productivity, their effect sizes vary over space and time. For example, relatively brief, intense pulses of marine nutrients are deposited in riparian forests during annual Pacific salmon Oncorhynchus spp. autumn spawning (Gende et al.