Microplastics as a vector for the transport of the bacterial fish pathogen species Aeromonas salmonicida

Microplastics is widespread in the marine environment where it can cause numerous negative effects. It can provide space for the growth of organisms and serves as a vector for the long distance transfer of marine microorganisms. In this study, we examined the sea surface concentrations of microplastics in the North Adriatic and characterized bacterial communities living on the microplastics. DNA from microplastics particles was isolated by three different methods, followed by PCR amplification of 16S rDNA, clone libraries preparation and phylogenetic analysis. 28 bacterial species were identified on the microplastics particles including Aeromonas spp. and hydrocarbon-degrading bacterial species. Based on the 16S rDNA sequences the pathogenic fish bacteria Aeromonas salmonicida was identified for the first time on microplastics. Because A. salmonicida is responsible for illnesses in fish, it is crucial to get answers if and how microplastics pollution is responsible for spreading of diseases.

Manca Kovač Viršek, Marija Nika Lovšin, Špela Koren, Andrej Kržan, Monika Peterlin, Marine Pollution Bulletin, Available online 7 September 2017, In Press

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Microplastics in livers of European anchovies (Engraulis encrasicolus, L.)

Microplastics (MPs) are thought to be ingested by a wide range of marine organisms before being excreted. However, several studies in marine organisms from different taxa have shown that MPs and nanoplastics could be translocated in other organs. In this study, we investigated the presence of MPs in the livers of commercial zooplanktivorous fishes collected in the field. The study focuses mainly on the European anchovy Engraulis encrasicolus but concerns also the European pilchard Sardina pilchardus and the Atlantic herring Clupea harengus. Two complementary methodologies were used to attest the occurrence of MPs in the hepatic tissue and to exclude contamination. 1) MPs were isolated by degradation of the hepatic tissue. 2) Cryosections were made on the livers and observed in polarized light microscopy. Both methods separately revealed that MPs, mainly polyethylene (PE), were translocated into the livers of the three clupeid species. In anchovy, 80 per cent of livers contained relatively large MPs that ranged from 124 μm to 438 μm, showing a high level of contamination. Two translocation pathways are hypothesized: (i) large particles found in the liver resulted from the agglomeration of smaller pieces, and/or (ii) they simply pass through the intestinal barrier. Further studies are however required to understand the exact process.

France Collard, Bernard Gilbert, Philippe Compere, Gauthier Eppe, Krishna Das,
Thierry Jauniaux, Eric Parmentier, Environmental Pollution,
Volume 229, October 2017, Pages 1000-1005

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Microplastic ingestion by Mullus surmuletus Linnaeus, 1758 fish and its potential for causing oxidative stress

A total of 417 striped red mullet, Mullus surmuletus, were analyzed to study microplastic ingestion and livers of fish were assessed to study effects of microplastics. Nearly one third (27.30%) of the individuals were quantified to ingest microplastics although there was no evidence of oxidative stress or cellular damage in the liver of fish which had ingested microplastics. A small increase in the activity of glutathione S-transferase (GST) of M. surmuletus was detected which could be suggesting an induction of the detoxification systems but these findings should be tested in laboratory conditions under a controlled diet and known concentration of microplastics. Fish from trammel fisheries, operating closer to land and targeting larger individuals, showed higher mean ingestion values than fish from trawling fisheries, and were related to body size, as microplastics ingested increased with total fish length. Consequently, ingestion values of microplastics were not related to sampling distance from land giving further evidence of the ubiquity of microplastics in the marine environment. Finally, Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that the vast majority of microplastics were filament type and polyethylene terephthalate (PET) was the main identified component.

C. Alomar, A Sureda, X. Capo and al., Environmental Research, Volume 159, November 2017, Pages 135-142

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Microplastics are polluting Lake Winnebago’s fish

A new study is raising concerns about the safety of eating fish from Lake Winnebago.

The research reveals tiny pieces of plastic are skirting the wastewater treatment process to end up in the lake, where they can soak up toxins and are likely being consumed by fish.

Experts say there’s a potential danger that those toxins could be passed on to people who consume fish from the lake.

“It’s definitely a concern,” said Kelly Reyer, outreach coordinator for the Fox-Wolf Watershed Alliance. “It can go through the food chain and potentially harm the ecosystem as well as public health because of people consuming the fish.”

Plastic microbeads had previously been found in the Great Lakes, prompting state legislation to phase out products that contain them, but experts didn’t know whether they were in Lake Winnebago or other inland waters. (…) (usatoday.com, 10/07/2017)

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Polybrominated diphenyl ethers in plastic products, indoor dust, sediment and fish from informal e-waste recycling sites in Vietnam: a comprehensive assessment of contamination, accumulation pattern, emissions, and human exposure

Residue concentrations of polybrominated diphenyl ethers (PBDEs) in different kinds of samples including consumer products, indoor dust, sediment and fish collected from two e-waste recycling sites, and some industrial, urban and suburban areas in Vietnam were determined to provide a comprehensive assessment of the contamination levels, accumulation pattern, emission potential and human exposure through dust ingestion and fish consumption. There was a large variation of PBDE levels in plastic parts of obsolete electronic equipment (from 1730 to 97,300 ng/g), which is a common result observed in consumer plastic products reported elsewhere. PBDE levels in indoor dust samples collected from e-waste recycling sites ranged from 250 to 8740 ng/g, which were markedly higher than those in industrial areas and household offices. Emission rate of PBDEs from plastic parts of disposed electronic equipment to dust was estimated to be in a range from 3.4 × 10−7 to 1.2 × 10−5 (year−1) for total PBDEs and from 2.9 × 10−7 to 7.2 × 10−6 (year−1) for BDE-209. Some fish species collected from ponds in e-waste recycling villages contained elevated levels of PBDEs, especially BDE-209, which were markedly higher than those in fish previously reported. Overall, levels and patterns of PBDE accumulation in different kinds of samples suggest significant emission from e-waste sites and that these areas are potential sources of PBDE contamination. Intakes of PBDEs via fish consumption were generally higher than those estimated through dust ingestion. Intake of BDE-99 and BDE-209 through dust ingestion contributes a large proportion due to higher concentrations in dust and fish. Body weight normalized daily intake through dust ingestion estimated for the e-waste recycling sites (0.10–3.46 ng/day/kg body wt.) were in a high range as compared to those reported in other countries. Our results highlight the potential releases of PBDEs from informal recycling activities and the high degree of human exposure and suggest the need for continuous investigations on environmental pollution and toxic impacts of e-waste-related hazardous chemicals.

Hoang Quoc Anh, Vu Duc Nam, Tran Manh Tri, Nguyen Manh Ha, Nguyen Thuy Ngoc, Pham Thi Ngoc Mai, Duong Hong Anh, Nguyen Hung Minh, Nguyen Anh Tuan, Tu Binh Minh, Environmental Geochemistry and Health, August 2017, Volume 39, Issue 4, pp 935–954

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Foraging preferences influence microplastic ingestion by six marine fish species from the Texas Gulf Coast

This study evaluated the influence of foraging preferences on microplastic ingestion by six marine fish species from the Texas Gulf Coast. A total of 1381 fish were analyzed and 42.4% contained ingested microplastic, inclusive of fiber (86.4%), microbead (12.9% %), and fragment (< 1.0%) forms. Despite a substantial overlap in diet, ordination of ingested prey items clustered samples into distinctive species groupings, reflective of the foraging gradient among species. Orthopristis chrysoptera displayed the lowest overall frequency of microplastic ingestion and the most distinctive ordination grouping, indicating their selective invertebrate foraging preferences. Cluster analysis of O. chrysoptera most closely classified microplastic with the ingestion of benthic invertebrates, whereas the ingestion of microplastic by all other species most closely classified with the ingestion of vegetation and shrimp. O. chrysoptera, as selective invertebrate foragers, are less likely to ingest microplastics than species exhibiting generalist foraging preferences and methods of prey capture.

Colleen A. Peters, Peyton A. Thomas, Kaitlyn B. Rieper, Susan P. Bratton, Marine Pollution Bulletin, Available online 11 July 2017, In Press

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Effects of dietary polyvinylchloride microparticles on general health, immune status and expression of several genes related to stress in gilthead seabream (Sparus aurata L.)

It is a long-recognized fact that marine plastic debris contaminates the oceans and seas of the entire world. Even though their effects on the aquatic biota are not well documented or understood. The effects of dietary polyvinylchloride microparticles (PVC-MPs) on the general health, immune status and some stress markers were studied using gilthead seabream (Sparus aurata) as a model of marine fish. Thirty specimens were randomly placed in three running sea water aquaria and fish in each aquarium received an experimental diet containing 0 (control), 100 or 500 mg kg−1 of PVC-MPs for 30 days. Metabolic parameters in serum indicated that the dietary intake of PVC-MPs negatively affected several vital organs. Humoral immune parameters were determined in serum and skin mucus. Cellular immune parameters were determined in head-kidney leucocytes. Concomitantly, the expression of different genes related to stress was studied in head-kidney and liver. Regarding head-kidney gene expression, prdx5 was significantly decreased by PVC-MPs intake for 15 and 30 days, respect to the values found in control fish. On the other hand, the expression of prdx1 and prdx3 were significantly increased by the PVC-MPs intake during 15 and 30 days, compared with the values found in control fish. Furthermore, the expression of hsp90 and ucp1 genes decreased and increased, respectively, in the liver of fish fed 500 mg kg−1 of PVC-MPs for 30 days. Although ingestion of PVC-MPs provoked few significant effects (mostly increases) in the main immune activities of gilthead seabream compared with the values found in control fish, PVC-MPs are recognized by the fish as stressors. Continued exposure of fish to high concentrations of PVC-MPs could have a negative impact on fish physiology due to the chronic stress produced.

Cristóbal Espinosa, Alberto Cuesta, María Ángeles Esteban, Fish & Shellfish Immunology, Vol. 68, Sept. 2017

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