Environmental risk of microplastics in a Mexican coastal lagoon ecosystem: Anthropogenic inputs and its possible human food risk

Synergistic effects of microplastic and lead trigger physiological and biochemical impairment in a mangrove crab

Microplastics (MP) are vectors for other environmental contaminants, such as metals, being a considerable problem, especially in the aquatic ecosystem. To investigate the combined effects of MP (high density polyethylene) with lead (Pb), we exposed the mangrove fiddler crab Minuca vocator to Pb (50 mg L-1), and MP (25 mg L-1) alone and in mixture, for 5 days. We aimed to determine Pb and MP bioaccumulation, as well as physiological (oxygen consumption and hemolymph osmolality) and biochemical (superoxide dismutase, catalase, glutathione peroxidase, and lipid peroxidation) traits effects. Co-exposure of MP and Pb significantly increased the bioaccumulation of Pb, but reduced MP tissue accumulation. Regarding the physiological traits, increasing osmolality and oxygen consumption rates compared to the control were observed, particularly in the combined Pb and MP exposure. As to biochemical traits, the combination of Pb and MP induced the most significant responses in the enzymatic profile antioxidant enzyme activity. The catalase (CAT), glutathione peroxidase (GPx), and dismutase superoxide (SOD) decreased compared to individual exposure effects; the combination of MP and Pb had a synergistic effect on promoting lipid peroxidation (LPO). The co-exposure of MP and Pb acted synergistically when compared to the effects of the isolated compounds. Due to the increasing MP contamination in mangroves, more severe physiological and biochemical effects can be expected on mangrove crabs exposed to metal contamination.

First Record of Microplastic Contamination in the Non-Native Dark False Mussel Mytilopsis leucophaeata (Bivalvia: Dreissenidae) in a Coastal Urban Lagoon

Microplastic contamination is a global concern due to its conspicuous presence in aquatic ecosystems and its toxic nature to environmental and human health. False mussels are among the most notable fresh- and brackish water invaders. The invasive Mytilopsis leucophaeata in Rodrigo de Freitas Lagoon-RFL (Rio de Janeiro, Brazil) is the most abundant macrofaunal invertebrate, widely established and distributed throughout the lagoon. This study aimed to assess microplastic contamination in this invasive filter feeder and evaluate its potential use as a bioindicator. Agglomerates (~100 mussels) were manually collected using a stainless-steel spatula in ten sampling areas distributed throughout the whole lagoon and kept frozen. In the laboratory, 60 individuals were sorted by area for soft-tissue digestion. Each pool of 10 soft-tissue mussels (n = 6 by area) was wet-weighted and then placed in a 150-mL decontaminated glass beaker with 50 mL of 10% KOH. Samples were heated (40 °C) for 48 h, and digested samples were filtered in glass-fiber membranes. Microplastics were found in all samples of mussels (n = 60) from RFL; the particles were mostly lower than 100 µm with a mean concentration (±SD) of 35.96 ± 47.64 MPs g wet-weight-1. Microplastics were distinguished in seven shapes with different occurrences in samples (%): fiber (43.3%); fragment (34.3%); film (16.3%); sponge/foam (4.9%); pellet (0.57%), rope/filaments (0.17%); and undefined (0.4%). Thirteen colors of microplastics were found, but transparent (54.94%), black (10.77%), and white (9.36%) were the most common. Mytilopsis leucophaeata were useful to assess microplastic contamination in RFL and might be preferentially used in other invaded brackish systems instead of native and often threatened bivalves. Our results confirm the effective application of bivalves as an indicator of coastal microplastic pollution.

Micro(nano)plastics in commercial foods: A review of their characterization and potential hazards to human health

Micro (nano)plastics (MNPs) are pollutants of worldwide concern for their ubiquitous environmental presence and associated impacts. The higher consumption of MNPs contaminated commercial food can cause potential adverse human health effects. This review highlights the evidence of MNPs in commercial food items and summarizes different sampling, extraction, and digestion techniques for the isolation of MNPs, such as oxidizing digestion, enzymatic digestion, alkaline digestion and acidic digestion. Various methods for the characterization and quantification of microplastics (MPs) are also compared, including μ-Raman spectroscopy, μ-Fourier transform infrared spectroscopy (FTIR), thermal analysis and Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Finally, we share our concerns about the risks of MNPs to human health through the consumption of commercial seafood. The knowledge of the potential human health impacts at a subcellular or molecular level of consuming mariculture products contaminated with MNPs is still limited. Moreover, MNPs are somewhat limited, hard to measure, and still contentious. Due to the nutritional significance of fish consumption, the risk of exposure to MNPs and the associated health effects are of the utmost importance.

Microplastics and heavy metals in shrimp Litopenaeus vannamei from the SAMARE lagoon, Gulf of California: Is it a case of combined MPs-Zn pollution in gills?

Microplastic (MPs) pollution studies in the coastal environment are increasing, as observed in the growing number of documents published yearly. However, studies regarding the combined effect of MPs and heavy metal (HMs) pollution are scarce, particularly in marine biota. Microplastics and HMs were investigated in the exoskeleton (EX), gills (GI), gastrointestinal tract (GT), and muscle (MU) of the shrimp Litopenaeus vannamei from the Santa María-La Reforma (SAMARE) lagoon, Mexico. Results showed that shrimp ingest mainly MPs of the fiber type (74.7%) and fragments (22.7%). The most frequent MP colors in the four tissues were transparent (61.4%-72.2%) and blue (3.2-36.4%) fibers. Microplastic abundance in the four tissues was 5.5 ± 0.5 MPs per individual. The predominant polymers found in most tissues were cotton and synthetic polyethylene-terephthalate (PET). Heavy metals exhibited wide variability depending on the tissue and metal; the highest Cu concentration in the GI was 138 ± 16 μg/g, while the highest Cd value was 0.40 ± 0.11 μg/g, Ni was 17.0 ± 8.3 μg/g, and Zn was 120 ± 18 μg/g in the GT. The relationship between MPs and HMs was significant and positive (p < 0.05) between MPs and Zn in the GI. This reveals a possible MPs-Zn interaction due to cotton and PET reactivity or is related to polymer manufacture. This study implies that an essential part of the world fisheries is a potential route for MPs and HMs. The problem is exacerbated due to the consumption of whole shrimp tissues consumed by humans. Considering Mexican shrimp consumption, and MPs in this study, the estimated intake was 594 MPs/capita/year. Future research requires MP monitoring in coastal lagoons that support wildlife and important fisheries and assess their effects combined with HMs.

The impact of microplastics on bivalve mollusks: A bibliometric and scientific review

Bivalves are important members of the ecosystem and their populations are declining globally, making them a concern for their role in ecosystem services and the fishing industry. Bivalves are excellent bioindicators of MPs pollution due to their widespread distribution, filtering capabilities, and close association with human health. Microplastics (MPs) have direct and indirect impacts on bivalves, affecting their physiology, habitat structure, food sources, and persistence of organic pollutants. This review provides an extensive overview of the impact of MPs on bivalves, covering various aspects such as their economic significance, ecological roles, and importance in biomonitoring environmental quality. The article presents the current state of knowledge on the sources and pathways of MPs in aquatic environments and their effects on bivalves. The mechanisms underlying the effects of MPs on bivalves, including ingestion, filtration activity, feeding inhibition, accumulation, bioaccumulation, and reproduction, are also discussed. Additionally, a bibliometric analysis of research on MPs in bivalves is presented, highlighting the number of papers, geographical distribution, and keyword clusters relating to MPs. Finally, the review emphasizes the importance of ongoing research and the development of mitigation strategies to reduce the negative effects of MPs pollution on bivalves and their habitats in oceans and coastal waters.