Persistent organic pollutants in fat of three species of Pacific pelagic longline caught sea turtles: Accumulation in relation to ingested plastic marine debris

Image 2In addition to eating contaminated prey, sea turtles may be exposed to persistent organic pollutants (POPs) from ingesting plastic debris that has absorbed these chemicals. Given the limited knowledge about POPs in pelagic sea turtles and how plastic ingestion influences POP exposure, our objectives were to: 1) provide baseline contaminant levels of three species of pelagic Pacific sea turtles; and 2) assess trends of contaminant levels in relation to species, sex, length, body condition and capture location. In addition, we hypothesized that if ingesting plastic is a significant source of POP exposure, then the amount of ingested plastic may be correlated to POP concentrations accumulated in fat. To address our objectives we compared POP concentrations in fat samples to previously described amounts of ingested plastic from the same turtles. Fat samples from 25 Pacific pelagic sea turtles [2 loggerhead (Caretta caretta), 6 green (Chelonia mydas) and 17 olive ridley (Lepidochelys olivacea) turtles] were analyzed for 81 polychlorinated biphenyls (PCBs), 20 organochlorine pesticides, and 35 brominated flame-retardants. The olive ridley and loggerhead turtles had higher ΣDDTs (dichlorodiphenyltrichloroethane and metabolites) than ΣPCBs, at a ratio similar to biota measured in the South China Sea and southern California. Green turtles had a ratio close to 1:1. These pelagic turtles had lower POP levels than previously reported in nearshore turtles. POP concentrations were unrelated to the amounts of ingested plastic in olive ridleys, suggesting that their exposure to POPs is mainly through prey. In green turtles, concentrations of ΣPCBs were positively correlated with the number of plastic pieces ingested, but these findings were confounded by covariance with body condition index (BCI). Green turtles with a higher BCI had eaten more plastic and also had higher POPs. Taken together, our findings suggest that sea turtles accumulate most POPs through their prey rather than marine debris.

Katharine E. Clukey, Christopher A. Lepczyk, George H. Balazs and al., Science of The Total Environment, Volumes 610–611, 1 January 2018, Pages 402-411

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Anthropogenic microlitter in the Baltic Sea water column

Microlitter (0.5–5 mm) concentrations in water column (depth range from 0 to 217.5 m) of the main Baltic Proper basins are reported. In total, 95 water samples collected in 6 research cruises in 2015–2016 in the Bornholm, Gdansk, and Gotland basins were analysed. Water from 10- and 30-litre Niskin bathometers was filtered through the 174 μm filters, and the filtrate was examined under optical microscope (40 ×). The bulk mean concentration was 0.40 ± 0.58 items per litre, with fibres making 77% of them. Other types of particles are the paint flakes (19%) and fragments (4%); no microbeads or pellets. The highest concentrations are found in the near-bottom samples from the coastal zone (2.2–2.7 items per litre max) and from near-surface waters (0.5 m) in the Bornholm basin (5 samples, 1.6–2.5 items per litre). Distribution of particles over depths, types, and geographical regions is presented.

A. Bagaev, L. Khatmullina, I. Chubarenko, Marine Pollution Bulletin, Available online 26 October 2017, In Press

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No increase in marine microplastic concentration over the last three decades – A case study from the Baltic Sea

Microplastic is considered a potential threat to marine life as it is ingested by a wide variety of species. Most studies on microplastic ingestion are short-term investigations and little is currently known about how this potential threat has developed over the last decades where global plastic production has increased exponentially. Here we present the first long-term study on microplastic in the marine environment, covering three decades from 1987 to 2015, based on a unique sample set originally collected and conserved for food web studies. We investigated the microplastic concentration in plankton samples and in digestive tracts of two economically and ecologically important planktivorous forage fish species, Atlantic herring (Clupea harengus) and European sprat (Sprattus sprattus), in the Baltic Sea, an ecosystem which is under high anthropogenic pressure and has undergone considerable changes over the past decades. Surprisingly, neither the concentration of microplastic in the plankton samples nor in the digestive tracts changed significantly over the investigated time period. Average microplastic concentration in the plankton samples was 0.21 ± 0.15 particles m− 3. Of 814 fish examined, 20% contained plastic particles, of which 95% were characterized as microplastic (< 5 mm) and of these 93% were fibres. There were no significant differences in the plastic content between species, locations, or time of day the fish were caught. However, fish size and microplastic in the digestive tracts were positively correlated, and the fish contained more plastic during summer than during spring, which may be explained by increased food uptake with size and seasonal differences in feeding activity. This study highlights that even though microplastic has been present in the Baltic environment and the digestive tracts of fishes for decades, the levels have not changed in this period. This underscores the need for greater understanding of how plastic is cycled through marine ecosystems. The stability of plastic concentration and contamination over time observed here indicates that the type and level of microplastic pollution may be more closely correlated to specific human activities in a region than to global plastic production and utilization as such.

Sabrina Beer, Anders Garm, Bastian Huwer, Jan Dierking, Torkel Gissel Nielsen, Science of The Total Environment, Available online 19 October 2017, In Press

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Export of plastic debris by rivers into the sea

Abstract ImageA substantial fraction of marine plastic debris originates from land-based sources and rivers potentially act as a major transport pathway for all sizes of plastic debris. We analyzed a global compilation of data on plastic debris in the water column across a wide range of river sizes. Plastic debris loads, both microplastic (particles <5 mm) and macroplastic (particles >5 mm) are positively related to the mismanaged plastic waste (MMPW) generated in the river catchments. This relationship is nonlinear where large rivers with  population-rich catchments delivering a disproportionately higher fraction of MMPW into the sea. The 10 top-ranked rivers transport 88–95% of the global load into the sea. Using MMPW as a predictor we calculate the global plastic debris inputs form rivers into the sea to range between 0.41 and 4 × 106 t/y. Due to the limited amount of data high uncertainties were expected and ultimately confirmed. The empirical analysis to quantify plastic loads in rivers can be extended easily by additional potential predictors other than MMPW, for example, hydrological conditions.

Christian Schmidt, Tobias Krauth, and Stephan Wagner, Environ. Sci. Technol., Article ASAP, October 11, 2017

Is it possible to implement a complex adaptive systems approach for marine systems? The experience of Italy and the Adriatic Sea

Highlights

• This paper evaluates the implementation of the MSFD in the Adriatic Sea.
• The MSFD is the first policy for marine complex adaptive systems in the EU.
• Ecological and jurisdictional boundaries overlap and cross-border cooperation is low.
• Integrative assessments of marine systems may be impossible to achieve.
• Relative isolation of theoretical approaches and management practices.

Emanuele Bigagli, Ocean & Coastal Management, Volume 149, 15 November 2017, Pages 81–95

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Export of microplastics from land to sea. A modelling approach

Quantifying the transport of plastic debris from river to sea is crucial for assessing the risks of plastic debris to human health and the environment. We present a global modelling approach to analyse the composition and quantity of point-source microplastic fluxes from European rivers to the sea. The model accounts for different types and sources of microplastics entering river systems via point sources. We combine information on these sources with information on sewage management and plastic retention during river transport for the largest European rivers. Sources of microplastics include personal care products, laundry, household dust and tyre and road wear particles (TRWP). Most of the modelled microplastics exported by rivers to seas are synthetic polymers from TRWP (42%) and plastic-based textiles abraded during laundry (29%). Smaller sources are synthetic polymers and plastic fibres in household dust (19%) and microbeads in personal care products (10%). Microplastic export differs largely among European rivers, as a result of differences in socio-economic development and technological status of sewage treatment facilities. About two-thirds of the microplastics modelled in this study flow into the Mediterranean and Black Sea. This can be explained by the relatively low microplastic removal efficiency of sewage treatment plants in the river basins draining into these two seas. Sewage treatment is generally more efficient in river basins draining into the North Sea, the Baltic Sea and the Atlantic Ocean. We use our model to explore future trends up to the year 2050. Our scenarios indicate that in the future river export of microplastics may increase in some river basins, but decrease in others. Remarkably, for many basins we calculate a reduction in river export of microplastics from point-sources, mainly due to an anticipated improvement in sewage treatment.

Max Siegfried, Albert A. Koelmans, Ellen Besseling, Carolien Kroeze, Water Research, Volume 127, 15 December 2017, Pages 249-257

Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief

Researcher and media alarms have caused plastic debris to be perceived as a major threat to humans and animals. However, although the waste of plastic in the environment is clearly undesirable for aesthetic and economic reasons, the actual environmental risks of different plastics and their associated chemicals remain largely unknown. Here we show how a systematic assessment of adverse outcome pathways based on ecologically relevant metrics for exposure and effect can bring risk assessment within reach. Results of such an assessment will help to respond to the current public worry in a balanced way and allow policy makers to take measures for scientifically sound reasons.

Albert A. Koelmans, Ellen Besseling, Edwin Foekema and al., Environ. Sci. Technol., Volume 51, Issue 20, Page 11513-11519, October 17, 2017

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