RESUMO
Increasing plastic contamination poses a serious threat to marine organisms. Microplastics (MPs) ingestion can represent a risk for the organism itself and for the ultimate consumer. Through the analysis of the gastrointestinal tract, coupled with stable isotope analysis on the muscle tissue, this study provides insights into the relationship between MPs pollution and ecology in two commercial marine species caught in the Central Tyrrhenian Sea: Aristaeomorpha foliacea and Parapenaeus longirostris. Stable isotope analysis was conducted to determine the trophic position and the trophic niche width. The gastrointestinal tracts were processed, and the resultant MPs were analysed under FT-IR spectroscopy to estimate the occurrence, abundance, and typology of the ingested MPs. The trophic level of the species was similar (P. longirostris TP = 3 ± 0.10 and A. foliacea TP = 3.1 ± 0.08), with an important trophic niche overlap, where 38% and 52% of P. longirostris and A. foliacea has ingested MPs, respectively. Though species-level differences may not be evident regarding MP's abundance per individual, a high degree of dissimilarity was noted in the typologies of ingested particles. This research provides valuable insights into how MPs enter marine trophic webs, stressing that isotopic niche analysis should be combined with other methods to explain in detail the differences in MPs ingestion.
RESUMO
Microplastic pollution is one of the greatest environmental concerns for contemporary times and the future. In the last years, the number of publications about microplastic contamination has increased rapidly and the list is daily updated. However, the lack of standard analytical approaches might generate data inconsistencies, reducing the comparability among different studies. The present study investigates the potential of two image processing tools (namely the shapeR package for R and ImageJ 1.52v) in providing an accurate characterization of the shape of microplastics using a restricted set of shape descriptors. To ascertain that the selected tools can measure small shape differences, we perform an experiment to verify the detection of pre-post variations in the shape of different microplastic types (i.e., nylon [NY], polyethylene [PE], polyethylene terephthalate [PET], polypropylene [PP], polystyrene [PS], and polyvinylchloride [PVC]) treated with mildly corrosive chemicals (i.e., 10% KOH at 60 °C, 30% H2O2 at 50 °C, and 15% H2O2 + 5% HNO3 at 40 °C; incubation time ≈ 12 h). Analysis of surface area variations returns results about the vulnerability of plastic polymers to digestive solutions that are aligned with most of the acquired knowledge. The largest decrease in surface area occurs for KOH-treated PET particles, while NY results in the most susceptible polymer to the 30% H2O2 treatment, followed by PVC and PS. PE and PP are the most resistant polymers to all the used treatments. The adopted methods to characterize microplastics seem reliable tools for detecting small differences in the shape and size of these particles. Then, the analytic perspectives that can be developed using such widely accessible and low-cost equipment are discussed.
Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos/análise , Peróxido de Hidrogênio/análise , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Polipropilenos/análise , Poliestirenos/análise , Polímeros , Polietileno/análise , Nylons , PolietilenotereftalatosRESUMO
A comprehensive understanding of the concentration of microplastics (MPs) in seawaters is essential to implement monitoring programs and understand the impacts on ecosystems, as required by the European legislation to protect the marine environment. In this context, the purpose of this study is to investigate the composition, quantity, and spatial distribution of microplastics from coastal to offshore areas in three Italian seawaters. In addition, the distribution of microplastics between surface and subsurface water layers was analyzed in order to better understand the dynamics of MPs in the upper layers of the water column. A total number of 6069 MPs (mean total concentration of 0.029 microplastics · m-2) were found to be heterogeneous in type, shape, and color. In general, MPs concentrations decrease with coastal distance, except when environmental forcings are predominant (such as sea currents). Moreover, the amount of surface MPs was almost four times that of subsurface microplastics, which consisted mostly of fibers. In light of these results, it becomes clear how critical it is to plan remediation actions and programs to minimize microplastic accumulations in the sea.
Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos , Ecossistema , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Água do Mar , Água , ItáliaRESUMO
This study provides a pilot investigation of the relationship between microplastic ingestion and the trophic ecology of three pelagic fish species (Engraulis encrasicolus, Scomber scombrus, and Trachurus trachurus) from Anzio coast, Tyrrhenian Sea (Western Mediterranean). Stable isotope analysis has been performed to determine the trophic position and the isotopic niche of the three species. Then, data on the occurrence, abundance, and diversity of ingested microplastics have been analyzed considering the observed foraging patterns. The detected differences in the estimated trophic position (E. encrasicolus = 3.08 ± 0.18; S. scombrus = 3.57 ± 0.21; T. trachurus = 4.07 ± 0.21), together with the absence of overlap in the isotopic niches confirm that the three examined species cover different ecological roles within the coastal-pelagic food web. Results from the analysis of ingested microplastics show that the trophic position has no remarkable effects on the incidence of microplastic ingestion, with no significant differences detected in terms of both frequency of occurrence and number of ingested microplastics per individual. However, differences among species emerge when considering the diversity of ingested microplastic types in terms of shape, size, color, and polymer composition. Species at higher trophic levels have shown to ingest a greater diversity of microplastics, including a significant increase in the size of the ingested particles (median surface area: 0.011 mm2 in E. encrasicolus; 0.021 mm2 in S. scombrus; 0.036 mm2 in T. trachurus). The ingestion of larger microplastics might be due to the larger gape sizes but also to active selection mechanisms, likely stimulated by the similarity of these particles to natural or potential prey of both S. scombrus and T. trachurus. Overall, this study suggests that microplastic ingestion can be affected by the different trophic position of fish species, providing new insights about the impact of microplastic contamination on the pelagic community.
Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Plásticos/análise , Cadeia Alimentar , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Peixes , Isótopos/análise , Mar MediterrâneoRESUMO
The development of monitoring programs based on bioindicators is crucial for assessing the impact of microplastic ingestion on marine organisms. This study presents results from an Italian pilot action aimed at investigating the suitability of a monitoring strategy based on a multispecies approach. The benthic-feeder Mullus barbatus, the demersal species Merluccius merluccius, and the pelagic-feeder species of the genus Scomber were used to assess the environmental contamination by microplastics in three different marine areas, namely Ancona (Adriatic Sea), Anzio (Tyrrhenian Sea), and Oristano (Western Sardinia). Microplastic ingestion frequencies were higher in samples from Anzio (26.7 %) and Ancona (25.0 %) than Oristano (14.4 %), suggesting a relationship between microplastic bioavailability and the proximity to urban settlements and river flows. Furthermore, microplastic ingestion was affected by the feeding habits of the examined species. The detected differences reinforce the hypothesis that a multispecies approach is needed to evaluate microplastic ingestion by marine animals.
Assuntos
Perciformes , Poluentes Químicos da Água , Animais , Microplásticos , Plásticos , Biomarcadores Ambientais , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Peixes , Ingestão de AlimentosRESUMO
The ingestion of plastic is becoming a major concern for various species and particularly for marine turtles across the globe. The loggerhead sea turtle (Caretta caretta) was recently chosen by the European Commission as a bio-indicator for plastic pollution within the Mediterranean basin. We further investigated which items this key species is more prone to ingest, following the standardised Marine Strategy Framework Directive protocols. Moreover, we integrated to this protocol the Fourier Transform Infrared Spectroscopy, which allowed us to determine the polymer type of each item. We analysed samples from 226 sea turtles from 2008 to 2017 in two areas of the western Mediterranean sub-region (sensu MSFD). In the Lazio area we found a frequency of occurrence of plastic ingestion of 78.33%, while in Sardinia 41.79%. The analysis of the litter categories, among all individuals, highlights a prevalence of user-sheet (Use-She; 69.13%) and user-fragment plastics (Use-Fra; 20.84%). In addition, the polymer analysis showed a dominance of polyethylene (65.98%) and polypropylene (26.23%). As a result, by looking at other works that have investigated polymer types and items sources, we are able to infer that 77.25% of the objects ingested by the C. caretta individuals are attributable to disposable daily-life objects managed in an improper way. Therefore, C. caretta apart from being an efficient bio-indicator for plastic pollution, highlighting spatial and temporal concentration differences, it could also be used to verify the effectiveness of the Single-use Plastic Directive (EU 2019/904).
Assuntos
Tartarugas , Poluentes da Água , Animais , Feminino , Conteúdo Gastrointestinal/química , Mar Mediterrâneo , Plásticos , Polímeros , Prevalência , Poluentes da Água/análiseRESUMO
Sea turtles are considered as bio-indicators for monitoring the efficiency of restoration measures to reduce marine litter impacts on health. However, the lack of extended and standardised empirical data has prevented the accurate analysis of the factors influencing litter ingestion and the relationships with individual health. Historic data collected from 1988 and standard data collected from 2016 were harmonised to enable such analyses on necropsied loggerhead turtles (Caretta caretta) in eight Mediterranean and North-East Atlantic countries. Litter was found in 69.24 % of the 1121 individuals, mostly single-use and fishing-related plastics. Spatial location, sex and life history stage explained a minor part of litter ingestion. While no relationships with health could be detected, indicating that all individuals can be integrated as bio-indicators, the mechanistic models published in literature suggest that the high proportion of plastics in the digestive contents (38.77 % per individual) could have long-term repercussions on population dynamics.
Assuntos
Tartarugas , Animais , Plásticos , Autopsia , Europa (Continente) , Ingestão de AlimentosRESUMO
The following protocol is intended to respond to the requirements set by the European Union's Marine Strategy Framework Directives (MSFD) for the D10C3 Criteria reported in the Commission Decision (EU), related to the amount of litter ingested by marine animals. Standardized methodologies for extracting litter items ingested from dead sea turtles along with guidelines on data analysis are provided. The protocol starts with the collection of dead sea turtles and classification of samples according to the decomposition status. Turtle necropsy must be performed in authorized centers and the protocol described here explains the best procedure for gastrointestinal (GI) tract isolation. The three parts of the GI (esophagus, stomach, intestine) should be separated, opened lengthways and contents filtered using a 1 mm mesh sieve. The article describes the classification and quantification of ingested litter, classifying GI contents into seven different categories of marine litter and two categories of natural remains. The quantity of ingested litter should be reported as total dry mass (weight in grams, with two decimal places) and abundance (number of items). The protocol proposes two possible scenarios to achieve the Good Environmental Status (GES). First: "There should be less than X% of sea turtles having Y g or more plastic in the GI in samples of 50-100 dead turtles from each sub-region", where Y is the average weight of plastic ingested and X% is the percentage of sea turtles with more weight (in grams) of plastic than Y. The second one, which considers the food remain versus plastic as a proxy of individual health, is: "There should be less than X% of sea turtles having more weight of plastic (in grams) than food remains in the GI in samples of 50-100 dead turtles from each sub-region".