Microscopic plastic items (microplastics) are ubiquitously present in aquatic ecosystems. With decreasing size their availability and potential to accumulate throughout food webs increase. However, ...little is known on the uptake of microplastics by freshwater invertebrates. To address this, we exposed species with different feeding strategies to 1, 10 and 90 µm fluorescent polystyrene spheres (3-3 000 particles mL
). Additionally, we investigated how developmental stages and a co-exposure to natural particles (e.g., food) modulate microplastic ingestion. All species ingested microplastics in a concentration-dependent manner with Daphnia magna consuming up to 6 180 particles h
, followed by Chironomus riparius (226 particles h
), Physella acuta (118 particles h
), Gammarus pulex (10 particles h
) and Lumbriculus variegatus (8 particles h
). D. magna did not ingest 90 µm microplastics whereas the other species preferred larger microplastics over 1 µm in size. In C. riparius and D. magna, size preference depended on the life stage with larger specimens ingesting more and larger microplastics. The presence of natural particles generally reduced the microplastics uptake. Our results demonstrate that freshwater invertebrates have the capacity to ingest microplastics. However, the quantity of uptake depends on their feeding type and morphology as well as on the availability of microplastics.
The accumulation of plastic litter in natural environments is a global issue. Concerns over potential negative impacts on the economy, wildlife, and human health provide strong incentives for ...improving the sustainable use of plastics. Despite the many voices raised on the issue, we lack a consensus on how to define and categorize plastic debris. This is evident for microplastics, where inconsistent size classes are used and where the materials to be included are under debate. While this is inherent in an emerging research field, an ambiguous terminology results in confusion and miscommunication that may compromise progress in research and mitigation measures. Therefore, we need to be explicit on what exactly we consider plastic debris. Thus, we critically discuss the advantages and disadvantages of a unified terminology, propose a definition and categorization framework, and highlight areas of uncertainty. Going beyond size classes, our framework includes physicochemical properties (polymer composition, solid state, solubility) as defining criteria and size, shape, color, and origin as classifiers for categorization. Acknowledging the rapid evolution of our knowledge on plastic pollution, our framework will promote consensus building within the scientific and regulatory community based on a solid scientific foundation.
Background
While the use of plastic materials has generated huge societal benefits, the ‘plastic age’ comes with downsides: One issue of emerging concern is the accumulation of plastics in the ...aquatic environment. Here, so-called microplastics (MP), fragments smaller than 5 mm, are of special concern because they can be ingested throughout the food web more readily than larger particles. Focusing on freshwater MP, we briefly review the state of the science to identify gaps of knowledge and deduce research needs.
State of the science
Environmental scientists started investigating marine (micro)plastics in the early 2000s. Today, a wealth of studies demonstrates that MP have ubiquitously permeated the marine ecosystem, including the polar regions and the deep sea. MP ingestion has been documented for an increasing number of marine species. However, to date, only few studies investigate their biological effects.
The majority of marine plastics are considered to originate from land-based sources, including surface waters. Although they may be important transport pathways of MP, data from freshwater ecosystems is scarce. So far, only few studies provide evidence for the presence of MP in rivers and lakes. Data on MP uptake by freshwater invertebrates and fish is very limited.
Knowledge gaps
While the research on marine MP is more advanced, there are immense gaps of knowledge regarding freshwater MP. Data on their abundance is fragmentary for large and absent for small surface waters. Likewise, relevant sources and the environmental fate remain to be investigated. Data on the biological effects of MP in freshwater species is completely lacking. The accumulation of other freshwater contaminants on MP is of special interest because ingestion might increase the chemical exposure. Again, data is unavailable on this important issue.
Conclusions
MP represent freshwater contaminants of emerging concern. However, to assess the environmental risk associated with MP, comprehensive data on their abundance, fate, sources, and biological effects in freshwater ecosystems are needed. Establishing such data critically depends on a collaborative effort by environmental scientists from diverse disciplines (chemistry, hydrology, ecotoxicology, etc.) and, unsurprisingly, on the allocation of sufficient public funding.
Global ocean warming results in an increase of infectious diseases including an elevated emergence of
Vibrio
spp. in Northern Europe. The European Centre for Disease Prevention and Control reported ...annual periods of high to very high risks of infection with
Vibrio
spp. during summer months along the North Sea and Baltic Sea coasts. Based on those facts, the risk of
Vibrio
infections associated with recreational bathing in European coastal waters increases. To obtain an overview of the seasonal and spatial distribution of potentially human pathogenic
Vibrio
spp. at German coasts, this study monitored
V. cholerae
,
V. parahaemolyticus
, and
V. vulnificus
at seven recreational bathing areas from 2017 to 2018, including the heat wave event in summer 2018. The study shows that all three
Vibrio
species occurred in water and sediment samples at all sampling sites. Temperature was shown to be the main driving factor of
Vibrio
abundance, whereas
Vibrio
community composition was mainly modulated by salinity. A species-specific rapid increase was observed at water temperatures above 10°C, reaching the highest detection numbers during the heat wave event with abundances of 4.5 log10 CFU+1/100 ml of seawater and 6.5 log10 CFU+1/100 g of sediment. Due to salinity, the dominant
Vibrio
species found in North Sea samples was
V. parahaemolyticus
, whereas
V. vulnificus
was predominantly detected in Baltic Sea samples. Most detections of
V. cholerae
were associated with estuarine samples from both seas.
Vibrio
spp. concentrations in sediments were up to three log higher compared to water samples, indicating that sediments are an important habitat for
Vibrio
spp. to persist in the environment. Antibiotic resistances were found against beta-lactam antibiotics (ampicillin 31%, cefazolin 36%, and oxacillin and penicillin 100%) and trimethoprim-sulfamethoxazole (45%). Moreover, isolates harboring pathogenicity-associated genes such as
trh
for
V. parahaemolyticus
as well as
vcg
,
cap
/
wcv
, and the 16S rRNA-type B variant for
V. vulnificus
were detected. All sampled
V. cholerae
isolates were identified as non-toxigenic non-O1/non-O139 serotypes. To sum up, increasing water temperatures at German North Sea and Baltic Sea coasts provoke elevated
Vibrio
numbers and encourage human recreational water activities, resulting in increased exposure rates. Owing to a moderate Baltic Sea salinity, the risk of
V. vulnificus
infections is of particular concern.
BackgroundExtreme weather events represent one of the most tangible impacts of anthropogenic climate change. They have increased in number and severity and a further increase is expected. This is ...accompanied by direct and indirect negative consequences for human health.MethodsFlooding events, storms and droughts are analysed here for Germany from a systemic perspective on the basis of a comprehensive literature review. Cascading risks beyond the initial event are also taken into account in order to depict downstream consequences.ResultsIn addition to the immediate health burdens caused by extreme weather events such as injuries, long-term consequences such as stress-related mental disorders occur. These stresses particularly affect certain vulnerable groups, e.g. older persons, children, pregnant women or first responders.ConclusionsA look at the cascading risks described in the international literature allows us to develop precautionary measures for adaptation to the consequences of climate change. Many adaptation measures protect against different risks at the same time. In addition to planning measures, these include, above all, increasing the population's ability to protect itself through knowledge and strengthening of social networks.
Over the past decade, microscopic plastic debris, known as microplastics, emerged as a contaminant of concern in marine and freshwater ecosystems. Although regularly detected in aquatic environments, ...the toxicity of those synthetic particles is not well understood. To address this, we investigated whether the exposure to microplastics adversely affects the amphipod Gammarus pulex, a key freshwater invertebrate.
Juvenile (6–9 mm) and adult (12–17 mm) individuals were exposed to irregular, fluorescent polyethylene terephthalate fragments (PET, 10–150 μm; 0.8–4,000 particles mL−1) for 24 h. Results show that body burden after 24 h depends on the dose and age of G. pulex with juveniles ingesting more microplastics than adults. After chronic exposure over 48 d, microplastics did not significantly affect survival, development (molting), metabolism (glycogen, lipid storage) and feeding activity of G. pulex.
This demonstrates that even high concentrations of PET particles did not negatively interfere with the analyzed endpoints. These results contradict previous research on marine crustaceans. Differences may result from variations in the exposure regimes (e.g., duration, particle concentrations), plastic characteristics (e.g., type, size, shape, additives) as well as the species-specific morphological, physiological and behavioral traits. As a detritivorous shredder G. pulex is adapted to feed on non-digestible materials and might, therefore, be less sensitive towards exposure to synthetic particles. Accordingly, we argue that the autecology needs to be taken into account and that research should focus on identifying traits that render species susceptible to microplastic exposure.
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•The freshwater amphipod Gammarus pulex readily ingested irregular PET microplastics (10–150 μm).•After 24 h exposure G. pulex contained predominantly particles <53 μm.•The body burden after 24 h depended on the dose and the age of G. pulex with a higher microplastic abundance in juveniles.•PET microplastic exposure over 48 d did not affect survival, feeding activity, energy reserves and molting of G. pulex.
We investigated the microplastics uptake and chronic toxicity of PET microplastics in Gammarus pulex. Despite high particle uptake, no effects on survival, molting, energy metabolism and feeding activity were observed.
Microplastics are emerging pollutants in aquatic and terrestrial environments. In the last years, several case studies and reviews have been published about microplastics in freshwater and marine ...environments. However, no standardized methods are available for sampling and sample preparation. Based on literature research, this review presents different techniques and methods for sampling as well as the preparation of microplastic samples from water, sediment and biota of freshwater and marine environments. Several methods are used for sampling and sample preparation (e.g., organic digestion and density separation) which influence the interpretation of results and hamper their comparability. The results clearly show that the basis for the interpretation of the results of microplastic monitoring is the consistency of a sampling strategy. Until standardization and harmonization both for sampling and sample preparation is implemented, further research about processing of samples and analysis techniques is necessary.
•Comparison of different sampling methods for water, sediment and biota.•Sample preparation with organic digestion and density separation.•Standardization and harmonization of sampling and sample preparation methods is needed.
Numerous studies on microplastics (MPs; Ø < 5 mm) in the aquatic environment have been published, but knowledge about the occurrence and ecological risks of MPs is limited. This is in part because ...current data on the distribution of MPs are comparable only to a limited extent, due to the many different methods of investigation. In addition, sample preparation is often difficult such that standard procedures are lacking. The aim of this work was to simplify the preparation of different kinds of MP samples. Our method makes use of the electrostatic behavior of plastic particles to facilitate their separation from sample matter, with up to 99% of the original sample mass removed without any loss of MPs. To determine the efficacy of this approach, four different materials (quartz sand, freshwater suspended particulate matter, freshwater sediment, and beach sand) were spiked with MPs (size: 0.063–5 mm from the seven most common types of plastics, one bioplastic type, polyethylene fibers, and tire wear. A modified electrostatic metal/plastic separator was used to reduce the sample mass and concentrate the plastics based on their physical separation. The recovery achieved with this method was as high as nearly 100% for each type of material. The method was then tested on plastic particles of different shapes and types isolated from the Rhine River. These were successfully electroseparated from the four materials, which demonstrated the utility of this method. Its advantages include the simplified handling and preparation of different field samples as well as a much shorter processing time, because after the last separation step there is hardly any biological material remaining in the sample fraction.
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•Simplified handling and preparation of different field samples in microplastic (MP) research.•Less harmful and less costly solvents are needed for MP separation.•The electrostatic method is not limited by particles densities, shape, fouling or age.•High biomass proportions have no influence on separation success.•Recovery reflects the high quality of this novel process.
Aquatic ecosystems are globally contaminated with microplastics (MP). However, comparative data on MP levels in freshwater systems is still scarce. Therefore, the aim of this study is to quantify MP ...abundance in water and sediment of the German river Elbe using visual, spectroscopic (Fourier-transform infrared spectroscopy) and thermo analytical (pyrolysis gas chromatography mass spectrometry) methods. Samples from eleven German sites along the German part of the Elbe were collected, both in the water and sediment phase, in order to better understand MP sinks and transport mechanisms. MP concentrations differed between the water and sediment phase. Sediment concentrations (mean: 3,350,000 particles m−3, 125–5000 μm MP) were in average 600,000-fold higher than water concentrations (mean: 5.57 particles m−3, 150–5000 μm MP). The abundance varied between the sampling sites: In sediments, the abundance decreased in the course of the river while in water samples no such clear trend was observed. This may be explained by a barrage retaining sediments and limiting tidal influence in the upstream parts of the river. Particle shape differed site-specifically with one site having exceptionally high quantities of spheres, most probably due to industrial emissions of PS-DVB resin beads. Suspended MP consisted predominantly of polyethylene and polypropylene whereas sediments contained a higher diversity of polymer types. Determined MP concentrations correspond well to previous results from other European rivers. In a global context, MP levels in the Elbe relate to the lower (water) to middle section (sediment) of the global range of MP concentrations determined for rivers worldwide. This highlights that elevated MP levels are not only found in single countries or continents, but that MP pollution is an issue of global concern.
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•Low to medium microplastic (MP) levels in the river Elbe•Much higher MP abundance in sediments compared to the water phase•Decreasing levels of MP in sediments over the course of the river•Higher polymer diversity in sediments compared to the water phase•Industrial emissions possibly caused MP hotspots
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