Like in the oceans, the bulk of the pollution in rivers and lakes is not in the form of plastic bottles and other large pieces, but tiny pieces called microplastics that would be hard to spot. “Three quarters of what we take out of the Great Lakes are less than a millimeter in size,” she says. “It’s basically the size of a period of a sentence.” These plastics are concerning to scientists because they are being ingested by a variety of aquatic organisms. (…) (pbs.org, 11/05/2017)
Microplastics are an emerging contaminant of concern in aquatic ecosystems. To better understand microplastic contamination in North American surface waters, we report for the first time densities of microplastics in Lake Winnipeg, the 11th largest freshwater body in the world. Samples taken 2014 to 2016 revealed similar or significantly greater microplastic densities in Lake Winnipeg compared with those reported in the Laurentian Great Lakes. Plastics in the lake were largely of secondary origin, overwhelmingly identified as fibres. We detected significantly greater densities of microplastics in the north basin compared to the south basin of the lake in 2014, but not in 2015 or 2016. Mean lake-wide densities across all years were comparable and not statistically different. Scanning electron microscopy with energy dispersive X-ray spectroscopy indicated that 23% of isolated particles on average were not plastic. While the ecological impact of microplastics on aquatic ecosystems is still largely unknown, our study contributes to the growing evidence that microplastic contamination is widespread even around sparsely-populated freshwater ecosystems, and provides a baseline for future study and risk assessments.
Philip J. Anderson, Sarah Warrack, Victoria Langen and al., Environmental Pollution, Volume 225, June 2017, Pages 223–231
We present the first study of microplastics in the sediments of Vembanad Lake, a Ramsar site in India. Microplastics are emerging pollutants of increasing environmental concern with a particle size of <5 mm, which originate from successive degradation of larger plastic debris or are manufactured as small granules and used in many applications. The impact of microplastics pollution on the environment and biota is not well known. Vast data exist in the literature on marine microplastics while reports on freshwater ecosystems are scarce. In this context, to examine the occurrence of microplastic particles (MPs) in the Vembanad Lake, samples were collected from ten sites and processed for microplastic extraction through density separation. Identification of the polymer components of MPs was done using micro Raman spectroscopy. MPs were recovered from all sediment samples, indicating their extensive distribution in the lake. The abundance of MPs recorded from the sediment samples is in the range of 96–496 particles m−2 with a mean abundance of 252.80 ± 25.76 particles m−2. Low density polyethylene has been identified as the dominant type of polymer component of the MPs. As clams and fishes are the major source of protein to the local population, the presence of MPs in the lake becomes critically important, posing a severe threat of contaminating the food web of this lake. This study, being the first report from India on MPs in lake sediments, provide impetus for further research on the distribution and impact of this emerging pollutant on the biota of many aquatic systems spread across India.
Plastic intake by marine vertebrates has been widely reported, but information about its presence in continental waterfowl is scarce. Here we analyzed faeces of waterbirds species (European coot, Fulica atra, mallard, Anas platyrhynchos and shelduck, Tadorna tadorna) for plastic debris in five wetlands in Central Spain. We collected 89 faeces of shelduck distributed in four lakes, 43.8% of them presented plastic remnants. Sixty percent of 10 faeces of European coot and 45% of 40 faeces of mallard contained plastic debris. Plastic debris found was of two types, threads and fragments, and were identified as remnants of plastic objects used in agricultural fields surrounding the lakes. Differences in prevalence of plastic in faeces, number of plastic pieces per excrement and size of the plastic pieces were not statistically significant between waterfowl species. Thus, our results suggest that plastic may also be frequently ingested by waterfowl in continental waters, at least in our study area. Future studies should address this potential problem for waterbird conservation in other wetlands to evaluate the real impact of this pollutant on waterbirds living in inland water.
J.A. Gil-Delgado, D. Guijarro, R.U. Gosálvez, G.M. López-Iborra, A. Ponz, A. Velasco, Environmental Pollution, Volume 220, Part A, January 2017, Pages 732–736
A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to sediment cores from three small isolated lakes (Plastic Lake, Lake 442, Lake Tettegouche) and Lake Ontario in the Great Lakes Region. Recoveries of the target compounds using the optimized acetonitrile/sodium hydroxide extraction ranged from 73% to 120%. The greatest concentrations of per- and polyfluorinated alkyl substances (PFASs) were recorded in sediment from Lake Ontario (ΣPFASs 13.1 ng/g), where perfluorooctane sulfonic acid (PFOS) contributed over 80% of the total. Concentrations in Lake Ontario were approximately 1–2 orders of magnitude greater than the more remote lakes subject to primarily atmospheric inputs. Whilst the PFAS contribution in Lake Ontario was dominated by PFOS, the more remote lakes contained sediment with higher proportions of PFCAs. Trace amounts of emerging PFASs (diPAPs and PFPiAs) were found in very recent surface Lake Ontario and remote lake sediments.
Rui Guo, David Megson, Anne L. Myers, Paul A. Helm, Chris Marvin, Patrick Crozier, Scott Mabury, Satyendra P. Bhavsar, Gregg Tomy, Matt Simcik, Brian McCarry, Eric J. Reine, Chemosphere, Volume 164, December 2016, Pages 535–546
In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 106–6.8 × 106 items/km2 in plankton net samples, 3.4–25.8 items/L in surface water, 11.0–234.6 items/kg dw in sediments and 0.2–12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100–1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake.
Lei Su, Yingang Xue, Lingyun Li, Dongqi Yang, Prabhu Kolandhasamy, Daoji Li, Huahong Shi, Environmental Pollution, Volume 216, September 2016, Pages 711–719
It is estimated in the United States that 8 trillion microbeads enter our waterways daily. Microplastics are typically discharged into local watersheds through wastewater treatment plant effluent and marine debris, with as much as 1600 synthetic fibers emanating from washing a single piece of clothing. In this project, we assessed microplastic load within Dreissena polymorpha (zebra mussels), Gammarus fasciatus (amphipods), fish, and Phalacrocorax auritus (double-crested cormorants) digestive tracts. Specimens were processed using KOH bath, followed by wet peroxide oxidation digests. Bioaccumulated microplastics were characterized based on type (e.g., fragment, pellet/bead, fiber, film, foam) and size. Results suggest that the majority of microplastics combined for all organisms investigated were fibers (67%), fragments (19%), films (10%), and pellets/beads (4%). No microplastics were observed in zebra mussels. Amphipods contained fibers (50%), fragments (25%), and films (25%). Species-specific trends were observed among fish, specifically Osmerus mordax (rainbow smelt), Cottus cognatus (slimy sculpin), and Micropterus salmoides (large-mouth bass) are primarily consuming fibers. Bluegill sunfish (Lepomis macrochirus) and rainbow smelt were the only species to consume pellets/beads (40%) and films (16%), respectively. Double-crested cormorants contained primarily fibers (78%), as well as films (19%), with minor contributions of pellets/beads and foam. Spatial distribution of microplastic load was greater in rainbow smelt at the most northern and southern sampling sites on Lake Champlain. In freshwater systems, microplastics absorb chemical pollutants and release plasticizers (e.g., carcinogens, neurotoxins, endocrine disruptors) into tissues, with the potential for fitness consequences in wildlife and humans.
Chad Hammer, Hope VanBrocklin, 05/01/2016