Plastic pollution in freshwater ecosystems: macro-, meso-, and microplastic debris in a floodplain lake

Plastic pollution is considered an important environmental problem by the United Nations Environment Programme, and it is identified, alongside climate change, as an emerging issue that might affect biological diversity and human health. However, despite research efforts investigating plastics in oceans, relatively little studies have focused on freshwater systems. The aim of this study was to estimate the spatial distribution, types, and characteristics of macro-, meso-, and microplastic fragments in shoreline sediments of a freshwater lake. Food wrappers (mainly polypropylene and polystyrene), bags (high- and low-density polyethylene), bottles (polyethylene terephthalate), and disposable Styrofoam food containers (expanded polystyrene) were the dominant macroplastics recorded in this study. Contrary to other studies, herein macroplastic item surveys would not serve as surrogates for microplastic items. This is disadvantageous since macroplastic surveys are relatively easier to conduct. Otherwise, an average of 25 mesoplastics (mainly expanded polystyrene) and 704 microplastic particles (diverse resins) were recorded per square meter in sandy sediments. Comparisons with other studies from freshwater and marine beaches indicated similar relevance of plastic contamination, demonstrating for the first time that plastic pollution is a serious problem in the Paraná floodplain lakes. This study is also valuable from a social/educational point of view, since plastic waste has been ignored in the Paraná catchment as a pollutant problem, and therefore, the outcome of the current study is a relevant contribution for decision makers.

Martin C. M. Blettler, Maria Alicia Ulla, Ana Pia Rabuffetti, Nicolás Garello, Environmental Monitoring and Assessment, , 189:581,

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Variation in plastic abundance at different lake beach zones – A case study

Image 2Plastic particles in marine and freshwater environments span from macroscopic to microscopic size classes. Each may have a different impact on individuals, populations and ecosystems, but still the wide variety of methods used in beach sediment sampling inhibit comparisons among studies and therefore hampers a risk assessment. A large portion of the uncertainties is due to differing sampling strategies.

By quantifying the alongshore distribution of macro- and microplastic particles within five beaches of Lake Garda, we aim to shed light on the accumulation behavior of microplastic particles at an exemplary lake which might give indications for potential sampling zones. The identification of plastic at the single particle level with a spatial resolution down to 1 μm was performed by Raman microspectroscopy. Given the time consuming approach we reduced the number of samples in the field but increased the spatial area where a single sample was taken, by utilizing a transect approach in combination with sediment cores (5 cm depth).

The study revealed that, in comparison to the water line and the high-water line, the drift line of all five beaches always contained plastic particles. Since the drift line accumulate particulate matter on a relatively distinct zone, it will enable a comparable sampling of microplastic particles. The applied sampling approach provided a representative method for quantifying microplastic down to 1 μm on a shore consisting of pebbles and sand. Hence, as first step towards a harmonization of beach sediment sampling we suggest to perform sampling at the drift line, although further methodological improvements are still necessary.

Hannes K. Imhof, Alexandra C.Wiesheu, Philipp M. Anger and al., Science of The Total Environment, Volumes 613–614, 1 February 2018, Pages 530-537

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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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Microplastics in the sediments of a UK urban lake

While studies on microplastics in the marine environment show their wide-distribution, persistence and contamination of biota, the freshwater environment remains comparatively neglected. Where studies on freshwaters have been undertaken these have been on riverine systems or very large lakes. We present data on the distribution of microplastic particles in the sediments of Edgbaston Pool, a shallow eutrophic lake in central Birmingham, UK. These data provide, to our knowledge, the first assessment of microplastic concentrations in the sediments of either a small or an urban lake and the first for any lake in the UK. Maximum concentrations reached 25–30 particles per 100 g dried sediment (equivalent to low hundreds kg−1) and hence are comparable with reported river sediment studies. Fibres and films were the most common types of microplastic observed. Spatial distributions appear to be due to similar factors to other lake studies (i.e. location of inflow; prevailing wind directions; propensity for biofouling; distribution of macroplastic debris) and add to the growing burden of evidence for microplastic ubiquity in all environments.

Rebecca Vaughan, Simon D. Turner, Neil L. Rose, Environmental Pollution, Volume 229, October 2017, Pages 10–18

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Freshwater’s macro microplastic problem

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)

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Microplastic contamination in Lake Winnipeg, Canada

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

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Microplastic pollution in Vembanad Lake, Kerala, India: The first report of microplastics in lake and estuarine sediments in India

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.

S. Sruthy, E.V. Ramasamy, Environmental Pollution, Volume 222, March 2017, Pages 315–322