Freshwater Compartments Research Articles

Assessment of microplastic contamination in the Loire River (France) throughout analysis of different biotic and abiotic freshwater matrices

The contamination of microplastics (MP) in freshwater environments represent a major way for the MP transport in the environment. The assessment of MP pollution in freshwater compartments is then important to visualize the pressure and the impacts on medium, and to set up necessary measures. In this context, this study focused on the influence of anthropogenic activities of a medium French city (Angers) on MP levels in samples collected from the Loire River, the longest river in France. Abiotic and biotic matrices were collected upstream and downstream Angers. A first analysis was performed based on microscopy to determine the size, colour and shape of suspected MP and a complementary analysis by μ-FTIR (micro-Fourier Transform InfraRed) was conducted to determine the composition of plastic particles. Three organisms belonging to different trophic levels were studied: when the MP level was expressed per individual, the lowest abundance of MP was found in Tubifex sp. Followed by Corbicula fluminea, while the highest was measured in Anguilla anguilla. To establish the relationship with their habitat, the presence of MP in sediment and water was also analysed. Therefore, this works constitutes a complete overview of the MP levels in freshwater abiotic and biotic matrices. Overall, the presence of MP in analysed samples did not follow a particular pattern, neither in the sites nor matrices: the characteristics depending on a multifactorial outcome (feeding mode, organism size …). However, correlation of MP pattern between clams and sediment was quite evident, while the one between worms and their habitat was not. This demonstrates the relevance of investigating plastic contamination both in biotic and abiotic matrices. Finally, a standardisation of sampling and analytical analysis protocols would be helpful to make comparisons between studies more robust.

Characterization of nitrogen emissions for freshwater eutrophication modelling in life cycle impact assessment at the damage level and urban scale

Human interventions mobilize massive nitrogen (N) emissions to freshwater and result in serious eutrophication impacts. Life cycle impact assessment (LCIA) provides a reliable quantitative tool to address the challenges of potential ecological impact induced by increasing nutrient inputs. However, characterization procedures that relate N emissions to ecological damage in freshwater ecosystems in LCIA methodology are still lacking. This study aims to propose a spatially explicit characterization model (1 km × 1 km) for N-induced freshwater eutrophication. A complete cause-effect chains linking the N emission with species loss endpoint impact was constructed, in which the site-specific fate factor modelling contained transfer and removal processes in terrestrial and freshwater compartments, and the mechanistic modelling of ecosystem exposure and damage effect were quantified with species loss. The eutrophication characterization was conducted with a case study in Guangzhou, China, and 1 km × 1 km spatial differentiation of eutrophication susceptibility was intuitively demonstrated, with higher values in the Pearl River Estuary area. Method comparisons and further improvements were discussed in support of model generalization and further application.

Agricultural drift depositional simulation of a copper-based fungicide and its effects on non-target terrestrial and freshwater compartments.

Our research investigated the potential impacts of the fungicide Bordeaux mixture drift processes on off-target species representing terrestrial vegetation and fluvial-lacustrine zooplankton. The simulation of drift events was carried out by a predictive scaling analysis of the quantities potentially exported to a predetermined area adjacent to an agricultural field. The theoretical rate of deposition on a terrestrial species, the lichen Pseudevernia furfuracea, was calculated following high (4 kg ha-1) and low (2 kg ha-1) rate treatments using anti-drift nozzles and non-anti-drift nozzles. The experimental set up consisted in 40 boxes holding lichen thalli, all stored in a climatic chamber for 40 days. Spraying of the fungicide was alternated with rainfall simulations to reproduce scenarios related to agricultural practices. Following a single simulation, anti-drift nozzles resulted in a higher overall load deposited per unit of lichen surface area compared to non-anti-drift nozzles, although both loads significantly differed from controls. However, only anti-drift nozzles, associated with the high rate, caused a remarkable impairment of several ecophysiological parameters, differing (p < 0.05) from controls. Rainfalls promoted activation of lichen metabolism, mitigating the cell damage, but exported only 2.5% of the copper deposited on the thalli surfaces. Nevertheless, the exposure of Daphnia magna neonates to leachates showed significant outcomes for the two rates. After only 24 h, leachates resulting from the high application rate led to widespread mortality, which appeared to be extremely relevant after 48 h, whereas the lower rate induced much lower toxicity for both exposure times.

Microplastics Occurrence in the European Common Frog (Rana temporaria) from Cottian Alps (Northwest Italy)

Microplastics (MPs) pollution is arousing growing attention, yet knowledge about its occurrence in amphibians is scant to date. With this study, we aimed to determine whether plastic (&gt;5000 μm) and MPs (10–5000 μm) could be detected in adult Rana temporaria from a high-mountain ecosystem (the Cottian Alps, northwest Italy). To do this, aquatic compartments and the digestive tract of adult R. temporaria were analyzed. Water, sediment, periphyton, aquatic macroinvertebrates, and tadpoles tested negative for plastic and MPs. Microplastics were detected in all the adult frogs (n = 5); all the identified items (one per specimen) were fibers (size range: 550.91–2355.51 µm). A statistically significant positive correlation between the particle length and frog size was recorded. The predominant fiber color was blue. The chemical composition was polyamide (60%), polyethylene (20%), and polyethylene terephthalate (20%). Since both the biotic and the abiotic freshwater compartments (tadpoles included) revealed the absence of MPs, it can be assumed that adult frogs ingest MPs from the surrounding terrestrial environment.

Seawater intrusion: an appraisal of taxa at most risk and safe salinity levels.

Seawater intrusion into low-lying coastal ecosystems carries environmental risks. Salinity levels at these coastal ecosystems may vary substantially, causing ecological effects from mortality to several sublethal endpoints, such as depression of rates of feeding, somatic growth, or reproduction. This review attempts to establish safe salinity levels for both terrestrial and freshwater temperate ecosystems by integrating data available in the literature. We have four specific objectives: (i) to identify the most sensitive ecological taxa to seawater intrusion; (ii) to establish maximum acceptable concentrations-environmental quality standards (MAC-EQSs) for sea water (SW) from species sensitivity distributions (SSDs); (iii) to compile from the literature examples of saline intrusion [to be used as predicted environmental concentrations (PECs)] and to compute risk quotients for the temperate zone; and (iv) to assess whether sodium chloride (NaCl) is an appropriate surrogate for SW in ecological risk assessments by comparing SSD-derived values for NaCl and SW and by comparing these with field data. Zooplankton, early life stages of amphibians and freshwater mussels were the most sensitive ecological receptors for the freshwater compartment, while soil invertebrates were the most sensitive ecological receptors for the terrestrial compartment. Hazard concentration 5% (HC5 ) values, defined as the concentration (herein measured as conductivity) that affects (causes lethal or sublethal effects) 5% of the species in a distribution, computed for SW were over 22 and 40 times lower than the conductivity of natural SW (≈ 52mS/cm) for the freshwater and soil compartment, respectively. This sensitivity of both compartments means that small increments in salinity levels or small SW intrusions might represent severe risks for low-lying coastal ecosystems. Furthermore, the proximity between HC5 values for the soil and freshwater compartments suggests that salinized soils might represent an additional risk for nearby freshwater systems. This sensitivity was corroborated by the derivation of risk quotients using real saline intrusion examples (PECs) collected from the literature: risk was >1 in 34 out of 37 examples. By contrast, comparisons of HC5 values obtained from SSDs in field surveys or mesocosm studies suggest that natural communities are more resilient to salinization than expected. Finally, NaCl was found to be slightly more toxic than SW, at both lethal and sublethal levels, and, thus, is suggested to be an acceptable surrogate for use in risk assessment.

The Mediterranean Region as a Paradigm of the Global Decoupling of N and P Between Soils and Freshwaters

AbstractThe global socio‐economic and agricultural expansion is accompanied by large inputs of nitrogen (N) and phosphorus (P) on land and by a serious alteration of the water cycle and water quality. The Mediterranean basin represents a paradigmatic region to study the entangled nutrient and water challenges because the region, where many of the world's climatic and socio‐economic gradients are present, is predicted to suffer severe water stress in the coming decades yet at the same time agricultural intensification and population are increasing in many rim countries. We here describe the biogeochemical budgets of N and P in 549 river basins for the 2000–2009 period, analyzing how the climatic gradient and water management practices affect the fluxes of N and P and their stoichiometric ratios. Average land inputs are 3,600 kg N km−2 yr−1 and 470 kg P km−2 yr−1, with a significant variation between basins (&gt;100 times) closely related to the stage of agricultural intensification. Moreover, the combination of aridity and water regulation can strongly alter the final balances, not only by changing the export of nutrients by rivers (riverine export is ca. 10% for N and 8% for P in arid basins), but also decoupling the N:P ratios between terrestrial and freshwater compartments.

Freshwater microbial community diversity in a rapidly changing High Arctic watershed.

Current models predict increases in High Arctic temperatures and precipitation that will have profound impacts on the Arctic hydrological cycle, including enhanced glacial melt and thawing of active layer soils. However, it remains uncertain how these changes will impact the structure of downstream resident freshwater microbial communities and ensuing microbially driven freshwater ecosystem services. Using the Lake Hazen watershed (Nunavut, Canada; 82°N, 71°W) as a sentinel system, we related microbial community composition (16S rRNA gene sequencing) to physicochemical parameters (e.g. dissolved oxygen and nutrients) over an annual hydrological cycle in three freshwater compartments within the watershed: (i) glacial rivers; (ii) active layer thaw-fed streams and waterbodies and (iii) Lake Hazen, into which (i) and (ii) drain. Microbial communities throughout these freshwater compartments were strongly interconnected, hydrologically, and often correlated with the presence of melt-sourced chemicals (e.g. dissolved inorganic carbon) as the melt season progressed. Within Lake Hazen itself, water column microbial communities were generally stable over spring and summer, despite fluctuating lake physicochemistry, indicating that these communities and the potential ecosystem services they provide therein may be resilient to environmental change. This work helps to establish a baseline understanding of how microbial communities and the ecosystem services they provide in Arctic watersheds might respond to future climate change.

Use of fresh water by an estuarine-resident marine catfish: evidence from gonadal and otolith chemistry analyses

AbstractIn this study, we examine how the Guri catfish Genidens genidens uses estuarine and freshwater habitats along the largest South American coastal lagoon, through the chemical analysis of otoliths and microscopic analysis of gonads. Chemical composition (Sr:Ca) of otolith edges allowed distinguishing between individuals who used the estuarine or freshwater compartments of the lagoon. The analysis of core-to-edge chemical profiles of each individual otolith revealed that the population may present two different patterns of habitat use along the lagoon. The ‘type 1’ pattern (89.5%) includes fish who appear to have been born in estuarine waters, whereas ‘type 2’ (9.5%) includes those fish born in fresh water. Nevertheless, juveniles from both patterns appear to migrate to estuarine waters. The gonad analysis shows G. genidens may reproduce in fresh water, as nearly 57% of all sampled fish were found to spawn in the freshwater portion of the lagoon. Also, the otolith core of many adult fish presented freshwater signatures, thus suggesting consistent fresh water use during early life. Our findings based on otolith and gonadal analyses challenge the previous classification of G. genidens as an estuarine resident. Rather, our results allow the suggestion that this species should be placed in the ‘estuarine and fresh water’ guild, which includes both fish completing their life cycles within the estuary and fish who consistently use freshwater habitats.

Safety and efficacy of sodium saccharin when used as a feed flavour for piglets, pigs for fattening, calves for rearing and calves for fattening.

Sodium saccharin is intended to be used as a sweetener in feed and water for drinking for piglets, pigs for fattening and veal calves. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers the proposed maximum use level of 150 mg sodium saccharin/kg feed as safe for calves and pigs for fattening. For piglets (sucking and weaned piglets), a lower level of 100 mg sodium saccharin/kg complete feed is considered safe. The corresponding maximum safe concentrations in water for drinking are 30 mg/L for piglets and 50 mg/L for pigs for fattening, respectively. The maximum safe concentrations of sodium saccharin in feed and water for drinking are derived under the premise that only one source, feed or water for drinking, contains the additive. The FEEDAP Panel concludes that no concern for the consumer would result from the use of sodium saccharin in feed and water for drinking at the dose considered safe for the target species. The precautions for handling the product proposed by the applicant are considered to be sufficient to ensure user safety. The FEEDAP Panel concludes that the use of sodium saccharin at the dose considered safe for target species is unlikely to have detrimental effects on the terrestrial and freshwater compartments. The high mobility and relative persistence of saccharin and the high persistency of its degradation product 4‐hydroxysaccharin indicate that groundwater contamination above 0.1 μg/L is likely to occur. Since the function of sodium saccharin in feed for the target species is essentially the same as that in food, the FEEDAP Panel concludes that no demonstration of efficacy is necessary.

Safety and efficacy of pyrazine derivatives including saturated ones belonging to chemical group 24 when used as flavourings for all animal species.

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 22 compounds belonging to chemical group 24 (pyrazine derivatives). They are currently authorised as flavours in food. The FEEDAP Panel concludes that: 2,3‐diethylpyrazine [14.005], 2‐ethyl‐3‐methylpyrazine [14.006], 5,6,7,8‐tetrahydroquinoxaline [14.015], 2,3,5,6‐tetramethylpyrazine [14.018], 2,3,5‐trimethylpyrazine [14.019], 2,5‐dimethylpyrazine [14.020], 2,6‐dimethylpyrazine [14.021], 2‐ethylpyrazine [14.022], 2‐ethyl‐3,5‐dimethylpyrazine [14.024], 2,5 or 6‐methoxy‐3‐methylpyrazine [14.025], 2‐methylpyrazine [14.027], acetylpyrazine [14.032], 6,7‐dihydro‐5‐methyl‐5H‐cyclopenta(b)pyrazine [14.037], 2‐isobutyl‐3‐methoxypyrazine [14.043], 2‐acetyl‐3‐ethylpyrazine [14.049], 2,3‐dimethylpyrazine [14.050], 2,3‐diethyl‐5‐methylpyrazine [14.056], 2‐(sec‐butyl)‐3‐methoxypyrazine [14.062], 3,(5‐ or 6‐)‐dimethyl‐2‐ethylpyrazine [14.100], 2‐ethyl‐3‐methoxypyrazine [14.112] and 2‐methoxy‐3‐methylpyrazine [14.126] are safe at the proposed maximum dose level (0.5 mg/kg complete feed) as feed for cattle, salmonids and non‐food‐producing animals, and at the proposed normal use level of 0.1 mg/kg complete feed for pigs and poultry; 5‐methylquinoxaline [14.028] are safe only at concentrations below the proposed use levels (0.08 mg/kg complete feed for cattle, salmonids and non‐food‐producing animals, and 0.05 mg/kg complete feed for pigs and poultry). No safety concern would arise for the consumer from the use of these compounds up to the highest proposed level in feeds. Hazards for skin and eye contact, and respiratory exposure are recognised for the majority of the compounds under application. Most are classified as irritating to the respiratory system. The proposed maximum use levels in feed are unlikely to have detrimental effects on the terrestrial and fresh water compartments. Because all the compounds under assessment are used in food as flavourings and their function in feed is essentially the same as that in food, no further demonstration of efficacy is necessary.

Safety and efficacy of aryl-substituted primary alcohol, aldehyde, acid, ester and acetal derivatives belonging to chemical group 22 when used as flavourings for all animal species.

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 18 compounds belonging to chemical group (CG) 22. They are currently authorised as flavours in food. The FEEDAP Panel concludes that: cinnamaldehyde [05.014] is safe at the maximum use level of 125 mg/kg complete feed for salmonids, veal calves and dogs, and at 25 mg/kg for the remaining target species; cinnamyl alcohol [02.017], 3‐phenylpropan‐1‐ol [02.031], 3‐(p‐cumenyl)‐2‐methylpropionaldehyde [05.045], α‐methylcinnamaldehyde [05.050], 3‐phenylpropanal [05.080], cinnamic acid [08.022], cinnamyl acetate [09.018], cinnamyl butyrate [09.053], 3‐phenylpropyl isobutyrate [09.428], cinnamyl isovalerate [09.459], cinnamyl isobutyrate [09.470], ethyl cinnamate [09.730], methyl cinnamate [09.740] and isopentyl cinnamate [09.742] are safe at the proposed maximum use level of 5 mg/kg complete feed for all target species; 2‐phenylpropanal [05.038], α‐pentylcinnamaldehyde [05.040] and α‐hexylcinnamaldehyde [05.041] are safe at the proposed maximum dose level of 5 mg/kg complete feed for all target species except cats, for which 1 mg/kg is safe. No safety concern would arise for the consumer from the use of these compounds up to the highest proposed level in feeds. Irritation and sensitisation hazards for skin and irritation for eye are recognised for the majority of the compounds under application. Respiratory exposure may also be hazardous. For the majority of the compounds belonging to CG 22, the maximum proposed use levels are considered safe for the environment. For α‐pentylcinnamaldehyde and α‐hexylcinnamaldehyde, a use level up to 0.1 mg/kg feed would not cause a risk for the terrestrial and fresh water compartments. Because all the compounds under assessment are used in food as flavourings and their function in feed is essentially the same as that in food, no further demonstration of efficacy is necessary.

A Review of the Properties and Processes Determining the Fate of Engineered Nanomaterials in the Aquatic Environment

Proper understanding of the basic processes and specific properties of engineered nanomaterials (NMs) that modify the fate and effects of NMs is crucial for NM-tailored risk assessment. This in turn requires developers of NMs and for regulators to consider the most important parameters governing the properties, behavior and toxicity of NMs. As fate and effect studies are commonly performed in laboratory settings, mimicking to a varying extent realistic exposure conditions, it is important to be able to extrapolate results of fate and effect studies in synthetic media to realistic environmental conditions. This requires detailed understanding of the processes controlling the fate and behavior of NMs in terrestrial and aquatic media, as dependent on the composition of the medium. It is the aim of this contribution to provide background reading to the NM and media specific properties and processes that affect the fate and behavior of NMs in aquatic environments, focusing on the specific properties of NMs that modulate the interactions in the aquatic environment. A general introduction on the dominant fate determining processes of NMs is supplemented by case studies on specific classes of NMs: metal NMs, stable oxides, iron oxides, and carbon nanotubes. Based on the synthesis of the current knowledge base toward essential data and information needs, the review provides a description of the particle specific properties and the water characteristics that need monitoring in order to allow for future quantification and extrapolation of fate and behavior properties of NMs in freshwater compartments of varying composition.

Spatial and temporal trends of metals and arsenic in German freshwater compartments

Cadmium, lead, mercury, copper, nickel, zinc, and arsenic were analyzed in suspended particulate matter (SPM), zebra mussels, and bream sampled yearly under the program of the German Environmental Specimen Bank (ESB) in the rivers Rhine, Elbe, Danube, Saar, Mulde, and Saale and in Lake Belau. Temporal and spatial trends were analyzed, correlations between metal levels in different specimen types assessed, and sampling sites ranked according to their metal levels by calculating a Multi-Metal Index (MMI) for every specimen type and site. SPM: Highest metal loads were detected in Mulde, Saale, and Elbe right downstream of the Saale confluence. In the Elbe, metal loads in SPM were mostly highest in the upper and middle section of the river while in Rhine and Saar concentrations increased downstream. Temporal trends since 2005 were detected only at three sites. Zebra mussel: MMIs were highest in the tidal section of the Elbe and the lower Rhine and lowest in Lake Belau and the upper Danube. Different temporal trends were detected since the early 1990s depending on site and metal. Bream: As, Pb, Cu, and Hg were analyzed in muscle tissue and Pb, Cd, Cu, and Zn in liver. For both tissues, MMIs were highest in Mulde and Saale and the lower and middle Elbe. Since the early 1990s, Hg, Pb, and Cu decreased in bream muscle at many sites while As increased at 6 of the 17 sites. The findings indicate that Hg, Pb, and Cu have obviously decreased in many freshwater ecosystems in recent years, whereas As and Ni levels have increased at several sites. Metal levels and temporal trends mostly differed between the specimen types under investigation and only few correlations between specimen types were detected. This underlines the importance of including different components of an ecosystem when assessing its environmental quality.