Do Freshwater Fish Eat Microplastics? A Review with A Focus on Effects on Fish Health and Predictive Traits of MPs Ingestion

Abstract

Microplastics (MPs) have received increasing attention in the last decade and are now considered among the most concerning emerging pollutants in natural environments. Here, the current knowledge on microplastic ingestion by wild freshwater fish is reviewed with a focus on the identification of possible factors leading to the ingestion of MPs and the consequences on fish health. Within the literature, 257 species of freshwater fishes from 32 countries have been documented to ingest MPs. MPs ingestion was found to increase with rising level of urbanization, although a direct correlation with MPs concentration in the surrounding water has not been identified. MPs ingestion was detected in all the published articles, with MPs presence in more than 50% of the specimens analyzed in one study out of two. Together with the digestive tract, MPs were also found in the gills, and there is evidence that MPs can translocate to different tissues of the organism. Strong evidence, therefore, exists that MPs may represent a serious risk for ecosystems, and are a direct danger for human health. Moreover, toxicological effects have also been highlighted in wild catches, demonstrating the importance of this problem and suggesting the need for laboratory experiments more representative of the environmental situation.

Evidence of microplastics in water and commercial fish from a high-altitude mountain lake (Lake Titicaca)

“…We observed that 3% of the fish evaluated in our study had ingested microplastics. This low occurrence of plastic particles was much lower than other freshwater fish species reported ( Galafassi et al, 2021 ). Furthermore, the relationship between microplastic ingestion, species, trophic guild, and fishing areas was not evident.…”

“…Specifically, our result may be consistent with the hypothesis that the amount of plastics ingested by omnivorous fish is associated with their wider food web ( Mizraji et al, 2017 ). It has frequently been suggested that fish living in freshwater environments near urbanized regions have a higher risk of microplastic ingestion, and a direct relationship with the level of urbanization has been observed ( Silva-Cavalcanti et al, 2017 ; Souza, Corrêa & Smith, 2020 ; Galafassi et al, 2021 ). However, several studies present evidence that higher environmental concentrations of microplastics do not necessarily translate into higher ingestion by aquatic biota ( McNeish et al, 2018 ; Talley, Venuti & Whelan, 2020 ; Sembiring et al, 2020 ).…”

“…, carelessness of the assessor or the quality of the microscopy) ( Hidalgo-Ruz et al, 2012 ). To date, there is no information on microplastic pollution in Bolivia or Lake Titicaca ( Castañeta et al, 2020 ; Galafassi et al, 2021 ). Therefore, despite its methodological limitations, our study provides evidence of the pollution of microplastics in Lake Titicaca’s habitat and fishery resources.…”

“…Microplastic pollution is well-studied in the marine environment, while research on plastic pollution in freshwater environments is still limited ( Mani et al, 2016 ; Blettler et al, 2017 ; Blettler et al, 2018 ; Dusaucy et al, 2021 ). The majority of plastic pollution studies in freshwaters were carried out in Europe and North America, leaving research to do in Asia and Latin America, where progress has been made in recent years ( Blettler et al, 2018 ; Alfonso, Arias & Piccolo, 2020 ; Galafassi et al, 2021 ).…”

Freshwater Fish Siberian Dace Ingest Microplastics in the Remote Yenisei Tributary

“…Studies showed that freshwater fish, along with marine organisms, tend to ingest submerged MPs. According to Galafassi et al [ 17 ], more than 250 species of freshwater fish have been documented to ingest MPs. Plastic microparticle ingestion has been detected in 32 countries, with presence in the digestive tract in more than 50% of the specimens analyzed in one study out of two.…”