Total and organic mercury concentrations were determined for males, females and juveniles of Euphausia superba collected at three discrete locations in the Scotia Sea (South Orkney Islands, South Georgia and Antarctic Polar Front) to assess spatial mercury variability in Antarctic krill. There was clear geographic differentiation in mercury concentrations, with specimens from the South Orkney Islands having total mercury concentrations 5 to 7 times higher than Antarctic krill from South Georgia and the Antarctic Polar Front. Mercury did not appear to accumulate with life-stage since juveniles had higher concentrations of total mercury (0.071 μg g⁻¹ from South Orkney Islands; 0.014 μg g⁻¹ from South Georgia) than adults (0.054 μg g⁻¹ in females and 0.048 μg g⁻¹ in males from South Orkney Islands; 0.006 μg g⁻¹ in females and 0.007 μg g⁻¹ in males from South Georgia). Results suggest that females may use egg laying as a mechanism to excrete mercury, with eggs having higher concentrations than the corresponding somatic tissue. Organic mercury makes up a minor percentage of total mercury (15–37%) with the percentage being greater in adults than in juveniles. When compared to euphausiids from other parts of the world, the concentration of mercury in Antarctic krill is within the same range, or higher, highlighting the global distribution of this contaminant. Given the high potential for biomagnification of mercury through food webs, concentrations in Antarctic krill may have deleterious effects on long-lived Antarctic krill predators.

Total and organic mercury concentrations were determined for males, females and juveniles of Euphausia superba collected at three discrete locations in the Scotia Sea (South Orkney Islands, South Georgia and Antarctic Polar Front) to assess spatial mercury variability in Antarctic krill. There was clear geographic differentiation in mercury concentrations, with specimens from the South Orkney Islands having total mercury concentrations 5 to 7 times higher than Antarctic krill from South Georgia and the Antarctic Polar Front. Mercury did not appear to accumulate with life-stage since juveniles had higher concentrations of total mercury (0.071 μg g-1 from South Orkney Islands; 0.014 μg g-1 from South Georgia) than adults (0.054 μg g-1 in females and 0.048 μg g-1 in males from South Orkney Islands; 0.006 μg g-1 in females and 0.007 μg g-1 in males from South Georgia). Results suggest that females may use egg laying as a mechanism to excrete mercury, with eggs having higher concentrations than the corresponding somatic tissue. Organic mercury makes up a minor percentage of total mercury (15-37%) with the percentage being greater in adults than in juveniles. When compared to euphausiids from other parts of the world, the concentration of mercury in Antarctic krill is within the same range, or higher, highlighting the global distribution of this contaminant. Given the high potential for biomagnification of mercury through food webs, concentrations in Antarctic krill may have deleterious effects on long-lived Antarctic krill predators. | published

In the present study Mytilus galloprovincialis mussels were exposed for 28 days to three salinities: 30 (control), 25 and 35. Simultaneously, organisms at each salinity were exposed to either the antimicrobial agent Triclosan (TCS) or the pharmaceutical drug Diclofenac (DIC) at 1 μg/L. Salinity alone and exposure to PPCPs changed mussel's metabolic capacity and oxidative status, but no additive or synergetic effects resulting from the combined exposures were observed. Overall, the metabolic capacity of mussels was decreased when exposed to TCS and DIC under control salinity, which was less pronounced at salinities out of the control level. TCS had a notorious effect over glutathione peroxidase activity while DIC exposure enhanced catalase response. Such defence mechanisms were able to prevent cellular damage but still a clear reduction in GSH/GSSG ratio after PPCPs exposures indicates oxidative stress which could compromise bivalve's performance to further stressing events.

In the present study Mytilus galloprovincialis mussels were exposed for 28 days to three salinities: 30 (control), 25 and 35. Simultaneously, organisms at each salinity were exposed to either the antimicrobial agent Triclosan (TCS) or the pharmaceutical drug Diclofenac (DIC) at 1 μg/L. Salinity alone and exposure to PPCPs changed mussel's metabolic capacity and oxidative status, but no additive or synergetic effects resulting from the combined exposures were observed. Overall, the metabolic capacity of mussels was decreased when exposed to TCS and DIC under control salinity, which was less pronounced at salinities out of the control level. TCS had a notorious effect over glutathione peroxidase activity while DIC exposure enhanced catalase response. Such defence mechanisms were able to prevent cellular damage but still a clear reduction in GSH/GSSG ratio after PPCPs exposures indicates oxidative stress which could compromise bivalve's performance to further stressing events. | published

10 pages, 5 figures, 2 tables | In the present study Mytilus galloprovincialis mussels were exposed for 28 days to three salinities: 30 (control), 25 and 35. Simultaneously, organisms at each salinity were exposed to either the antimicrobial agent Triclosan (TCS)or the pharmaceutical drug Diclofenac (DIC)at 1 μg/L. Salinity alone and exposure to PPCPs changed mussel's metabolic capacity and oxidative status, but no additive or synergetic effects resulting from the combined exposures were observed. Overall, the metabolic capacity of mussels was decreased when exposed to TCS and DIC under control salinity, which was less pronounced at salinities out of the control level. TCS had a notorious effect over glutathione peroxidase activity while DIC exposure enhanced catalase response. Such defence mechanisms were able to prevent cellular damage but still a clear reduction in GSH/GSSG ratio after PPCPs exposures indicates oxidative stress which could compromise bivalve's performance to further stressing events | Francesca Coppola benefited from PhD grant (SFRH/BD/118582/2016) given by the National Funds through the Portuguese Science Foundation (FCT), supported by FSE and Programa Operacional Capital Humano (POCH) e European Union. Rosa Freitas benefited from a Research position funded by Integrated Programme of SR&TD “Smart Valorization of Endogenous Marine Biological Resources Under a Changing Climate” (reference Centro-01-0145-FEDER-000018), co-funded by Centro 2020 program, Portugal 2020, European Union, through the European Regional Development Fund. Thanks are due for the financial support to CESAM (UID/AMB/50017/2019), to FCT/MEC through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. This work was also financially supported by the project BISPECIAl: BIvalveS under Polluted Environment and ClImate chAnge (POCI-01-0145-FEDER-028425) funded by FEDER, through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI), and by national funds (OE), through FCT/MCTES; and by the Spanish Ministry of Economy, Industry and Competitivity: AimCost project (ref CGL2016-76332-R MINECO/FEDER/UE). Rosa Freitas and Montserrat Solé are also funded by CYTED, through the RED Iberoamericana RIESCOS (419RT0578) | Peer Reviewed

Localised sites in Antarctica are contaminated with mixtures of metals, yet the risk this contamination poses to the marine ecosystem is not well characterised. Recent research showed that two Antarctic marine microalgae have antagonistic responses to a mixture of five common metals (Koppel et al., 2018a). However, the metal accumulating potential and risk to secondary consumers through dietary exposure are still unknown. This study investigates cellular accumulation following exposure to a mixture of cadmium, copper, nickel, lead, and zinc for the Antarctic marine microalgae, Phaeocystis antarctica and Cryothecomonas armigera. In both microalgae, cellular cadmium, copper, and lead concentrations increased with increasing exposures while cellular nickel and zinc did not. For both microalgae, copper in the metal mixture drives inhibition of growth rate with R2 values > -0.84 for all cellular fractions in both species and the observed antagonism was likely caused by zinc competition, having significantly positive partial regressions. Metal accumulation to P. antarctica and C. armigera is likely to be toxic to consumer organisms, with low exposure concentrations resulting in cellular concentrations of 500 and 1400 × 10−18 mol Zn cell−1 and 160 and 320 × 10−18 mol Cu cell−1, respectively.

© 2019 Localised sites in Antarctica are contaminated with mixtures of metals, yet the risk this contamination poses to the marine ecosystem is not well characterised. Recent research showed that two Antarctic marine microalgae have antagonistic responses to a mixture of five common metals (Koppel et al., 2018a). However, the metal accumulating potential and risk to secondary consumers through dietary exposure are still unknown. This study investigates cellular accumulation following exposure to a mixture of cadmium, copper, nickel, lead, and zinc for the Antarctic marine microalgae, Phaeocystis antarctica and Cryothecomonas armigera. In both microalgae, cellular cadmium, copper, and lead concentrations increased with increasing exposures while cellular nickel and zinc did not. For both microalgae, copper in the metal mixture drives inhibition of growth rate with R2 values > -0.84 for all cellular fractions in both species and the observed antagonism was likely caused by zinc competition, having significantly positive partial regressions. Metal accumulation to P. antarctica and C. armigera is likely to be toxic to consumer organisms, with low exposure concentrations resulting in cellular concentrations of 500 and 1400 × 10−18 mol Zn cell−1 and 160 and 320 × 10−18 mol Cu cell−1, respectively. Metal accumulation from mixtures in two Antarctic marine microalgae has the potential to cause dietary toxicity to secondary consumers in the Southern Ocean food web. Extra and intracellular partitioning shows that zinc is protective of copper toxicity at low effect concentrations.

In recent years, the impact of Plant Protection Products (PPPs) on insect pollinator decline has stimulated significant amounts of research, as well as political and public interest. PPP residues have been found in various bee-related matrices, resulting in governmental bodies worldwide releasing guidance documents on methods for the assessment of the overall risk of PPPs to different bee species. An essential part of these risk assessments are PPP residues found in pollen and nectar, as they represent a key route of exposure. However, PPP residue values in these matrices exhibit large variations and are not available for many PPPs and crop species combinations, which results in inaccurate estimations and uncertainties in risk evaluation. Additionally, residue studies on pollen and nectar are expensive and practically challenging. An extrapolation between different cropping scenarios and PPPs is not yet justified, as the behaviour of PPPs in pollen and nectar is poorly understood. Therefore, this review aims to contribute to a better knowledge and understanding of the fate of PPP residues in pollen and nectar and to outline knowledge gaps and future research needs. The literature suggests that four primary factors, the crop type, the application method, the physicochemical properties of a compound and the environmental conditions have the greatest influence on PPP residues in pollen and nectar. However, these factors consist of many sub-factors and initial effects may be disguised by different sampling methodologies, impeding their exact characterisation. Moreover, knowledge about these factors is ambiguous and restricted to a few compounds and plant species. We propose that future research should concentrate on identifying relationships and common features amongst various PPP applications and crops, as well as an overall quantification of the described parameters; in order to enable a reliable estimation of PPP residues in pollen, nectar and other bee matrices.

In recent years, the impact of Plant Protection Products (PPPs) on insect pollinator decline has stimulated significant amounts of research, as well as political and public interest. PPP residues have been found in various bee-related matrices, resulting in governmental bodies worldwide releasing guidance documents on methods for the assessment of the overall risk of PPPs to different bee species. An essential part of these risk assessments are PPP residues found in pollen and nectar, as they represent a key route of exposure. However, PPP residue values in these matrices exhibit large variations and are not available for many PPPs and crop species combinations, which results in inaccurate estimations and uncertainties in risk evaluation. Additionally, residue studies on pollen and nectar are expensive and practically challenging. An extrapolation between different cropping scenarios and PPPs is not yet justified, as the behaviour of PPPs in pollen and nectar is poorly understood. Therefore, this review aims to contribute to a better knowledge and understanding of the fate of PPP residues in pollen and nectar and to outline knowledge gaps and future research needs. The literature suggests that four primary factors, the crop type, the application method, the physicochemical properties of a compound and the environmental conditions have the greatest influence on PPP residues in pollen and nectar. However, these factors consist of many sub-factors and initial effects may be disguised by different sampling methodologies, impeding their exact characterisation. Moreover, knowledge about these factors is ambiguous and restricted to a few compounds and plant species. We propose that future research should concentrate on identifying relationships and common features amongst various PPP applications and crops, as well as an overall quantification of the described parameters; in order to enable a reliable estimation of PPP residues in pollen, nectar and other bee matrices.

Due to the growing concern about the presence of microplastics (MP) in the environment, the number of studies evaluating the toxicity of these small persistent particles on different marine species has increased in recent years. Few studies have addressed their impact on marine phytoplankton, a subject of great concern since they are primary producers of the aquatic food web. The aim of this study is to unravel the cytotoxicity of 2.5 μg mL⁻¹ unlabelled amino-modified polystyrene beads of different sizes (0.5 and 2 μm) on the marine diatom Chaetoceros neogracile. In addition to traditional growth and photosynthesis endpoints, several physiological and biochemical parameters were monitored every 24 h in C. neogracile cells by flow cytometry during their exponential growth (72 h). Dynamic Light Scattering measurements revealed the strong aggregation and the negative charge of the beads assayed in the culture medium, which seemed to minimize particle interaction with cells and potentially associated impacts. Indeed, MP were not attached to the microalgal cell wall, as evidenced by scanning electron micrographs. Cell growth, morphology, photosynthesis, reactive oxygen species levels and membrane potential remained unaltered. However, exposure to MP significantly decreased the cellular esterase activity and the neutral lipid content. Microalgal oil bodies could serve as an energy source for maintaining a healthy cellular status. Thus, MP-exposed cells modulate their energy metabolism to properly acclimate to the stress conditions.

Due to the growing concern about the presence of microplastics (MP) in the environment, the number of studies evaluating the toxicity of these small persistent particles on different marine species has increased in recent years. Few studies have addressed their impact on marine phytoplankton, a subject of great concern since they are primary producers of the aquatic food web. The aim of this study is to unravel the cytotoxicity of 2.5 μg mL−1 unlabelled amino-modified polystyrene beads of different sizes (0.5 and 2 μm) on the marine diatom Chaetoceros neogracile. In addition to traditional growth and photosynthesis endpoints, several physiological and biochemical parameters were monitored every 24 h in C. neogracile cells by flow cytometry during their exponential growth (72 h). Dynamic Light Scattering measurements revealed the strong aggregation and the negative charge of the beads assayed in the culture medium, which seemed to minimize particle interaction with cells and potentially associated impacts. Indeed, MP were not attached to the microalgal cell wall, as evidenced by scanning electron micrographs. Cell growth, morphology, photosynthesis, reactive oxygen species levels and membrane potential remained unaltered. However, exposure to MP significantly decreased the cellular esterase activity and the neutral lipid content. Microalgal oil bodies could serve as an energy source for maintaining a healthy cellular status. Thus, MP-exposed cells modulate their energy metabolism to properly acclimate to the stress conditions.

Nanotechnology and use of nanomaterials (NMs) improve life quality, economic growth and environmental health. However, the increasing production and use of NMs in commercial products has led to concerns about their potential toxicity on human and environment health, as well as its toxicological classification and regulation. In this context, there is an urgent need to standardize and validate procedures for nanotoxicity testing. Since the zebrafish embryotoxicity test (ZET) has been indicated as a suitable approach for the toxicity assessment of traditional and emergent pollutants, the aim of this review is to summarize the existing literature on embryotoxic and teratogenic effects of NMs on zebrafish. In addition, morphological changes in zebrafish embryos induced by NMs were classified in four reaction models, allowing classification of the mode of action and toxicity of different types of NM. Revised data showed that the interaction and bioaccumulation of NMs on zebrafish embryos were associated to several toxic effects, while the detoxification process was limited. In general, NMs induced delayed hatching, circulatory changes, pigmentation and tegumentary alterations, musculoskeletal disorders and yolk sac alterations on zebrafish embryos. Recommendations for nanotoxicological tests are given, including guidance for future research. This review reinforces the use of the ZET as a suitable approach to assess the health risks of NM exposure.

Embargo until 28 June 2021 | Nanotechnology and use of nanomaterials (NMs) improve life quality, economic growth and environmental health. However, the increasing production and use of NMs in commercial products has led to concerns about their potential toxicity on human and environment health, as well as its toxicological classification and regulation. In this context, there is an urgent need to standardize and validate procedures for nanotoxicity testing. Since the zebrafish embryotoxicity test (ZET) has been indicated as a suitable approach for the toxicity assessment of traditional and emergent pollutants, the aim of this review is to summarize the existing literature on embryotoxic and teratogenic effects of NMs on zebrafish. In addition, morphological changes in zebrafish embryos induced by NMs were classified in four reaction models, allowing classification of the mode of action and toxicity of different types of NM. Revised data showed that the interaction and bioaccumulation of NMs on zebrafish embryos were associated to several toxic effects, while the detoxification process was limited. In general, NMs induced delayed hatching, circulatory changes, pigmentation and tegumentary alterations, musculoskeletal disorders and yolk sac alterations on zebrafish embryos. Recommendations for nanotoxicological tests are given, including guidance for future research. This review reinforces the use of the ZET as a suitable approach to assess the health risks of NM exposure. | publishedVersion

The effects of exposure to different levels of ionising radiation were assessed on the genetic, epigenetic and microbiome characteristics of the “hologenome” of earthworms collected at sites within the Chernobyl exclusion zone (CEZ). The earthworms Aporrectodea caliginosa (Savigny, 1826) and Octolasion lacteum (Örley, 1881) were the two species that were most frequently found at visited sites, however, only O. lacteum was present at sufficient number across different exposure levels to enable comparative hologenome analysis. The identification of morphotype O. lacteum as a probable single clade was established using a combination of mitochondrial (cytochrome oxidase I) and nuclear genome (Amplified Fragment Length Polymorphism (AFLP) using MspI loci). No clear site associated differences in population genetic structure was found between populations using the AFLP marker loci. Further, no relationship between ionising radiation exposure levels and the percentage of methylated loci or pattern of distribution of DNA methylation marks was found. Microbiome structure was clearly site dependent, with gut microbiome community structure and diversity being systematically associated with calculated site-specific earthworm dose rates. There was, however, also co-correlation between earthworm dose rates and other soil properties, notably soil pH; a property known to affect soil bacterial community structure. Such co-correlation means that it is not possible to attribute microbiome changes unequivocally to radionuclide exposure. A better understanding of the relationship between radionuclide exposure soil properties and their interactions on bacterial microbiome community response is, therefore, needed to establish whether these the observed microbiome changes are attributed directly to radiation exposure, other soil properties or to an interaction between multiple variables at sites within the CEZ.

The effects of exposure to different levels of ionising radiation were assessed on the genetic, epigenetic and microbiome characteristics of the “hologenome” of earthworms collected at sites within the Chernobyl exclusion zone (CEZ). The earthworms Aporrectodea caliginosa (Savigny, 1826) and Octolasion lacteum (Örley, 1881) were the two species that were most frequently found at visited sites, however, only O. lacteum was present at sufficient number across different exposure levels to enable comparative hologenome analysis. The identification of morphotype O. lacteum as a probable single clade was established using a combination of mitochondrial (cytochrome oxidase I) and nuclear genome (Amplified Fragment Length Polymorphism (AFLP) using MspI loci). No clear site associated differences in population genetic structure was found between populations using the AFLP marker loci. Further, no relationship between ionising radiation exposure levels and the percentage of methylated loci or pattern of distribution of DNA methylation marks was found. Microbiome structure was clearly site dependent, with gut microbiome community structure and diversity being systematically associated with calculated site-specific earthworm dose rates. There was, however, also co-correlation between earthworm dose rates and other soil properties, notably soil pH; a property known to affect soil bacterial community structure. Such co-correlation means that it is not possible to attribute microbiome changes unequivocally to radionuclide exposure. A better understanding of the relationship between radionuclide exposure soil properties and their interactions on bacterial microbiome community response is, therefore, needed to establish whether these the observed microbiome changes are attributed directly to radiation exposure, other soil properties or to an interaction between multiple variables at sites within the CEZ.

BADGE (bisphenol A diglycidyl ether) is a synthesis product of bisphenol A (BPA), which, like other plasticizers, can cross the human placenta and reach the foetus. However, compared to BPA, there is almost no toxicological information. This work investigates the toxicity, endocrine and lipid disruption potential of BADGE and its hydrolysed and chlorinated derivatives (BADGE·H₂O and BADGE·2HCl) in human placental JEG-3 cells. The analysis of culture medium by HPLC-ESI(+)-QqQ evidenced a good bioavailability of BADGE·2HCl and BADGE·H₂O, but low stability of BADGE. Regardless, BADGE·2HCl and BADGE showed higher cytotoxicity than BADGE·H₂O, which was the only compound that significantly inhibited CYP19 activity (IC₅₀ 49 ± 5 μM). JEG-3 cells lipidome analyzed by FIA-ESI(+/−)-Orbitrap was significantly altered by exposure to BADGE·2HCl and BADGE at concentrations at the low μM range. BADGE·2HCl lead to a strong decrease of diacyl- and triacyl-glycerides (DGs,TGs) together with some membrane lipids, while BADGE lead to an accumulation of TGs. The results evidence the ability of BADGE and derivatives to affect placental lipid handling and to modulate placental CYP19 activity (BADGE·H₂O) and highlights the need to monitor human exposure to these compounds, at least as intensely as BPA is monitored.

BADGE (bisphenol A diglycidyl ether) is a synthesis product of bisphenol A (BPA), which, like other plasticizers, can cross the human placenta and reach the foetus. However, compared to BPA, there is almost no toxicological information. This work investigates the toxicity, endocrine and lipid disruption potential of BADGE and its hydrolysed and chlorinated derivatives (BADGE·H2O and BADGE·2HCl) in human placental JEG-3 cells. The analysis of culture medium by HPLC-ESI(+)-QqQ evidenced a good bioavailability of BADGE·2HCl and BADGE·H2O, but low stability of BADGE. Regardless, BADGE·2HCl and BADGE showed higher cytotoxicity than BADGE·H2O, which was the only compound that significantly inhibited CYP19 activity (IC50 49 ± 5 μM). JEG-3 cells lipidome analyzed by FIA-ESI(+/−)-Orbitrap was significantly altered by exposure to BADGE·2HCl and BADGE at concentrations at the low μM range. BADGE·2HCl lead to a strong decrease of diacyl- and triacyl-glycerides (DGs,TGs) together with some membrane lipids, while BADGE lead to an accumulation of TGs. The results evidence the ability of BADGE and derivatives to affect placental lipid handling and to modulate placental CYP19 activity (BADGE·H2O) and highlights the need to monitor human exposure to these compounds, at least as intensely as BPA is monitored. Bisphenol A diglycidyl ether and derivatives disrupt placenta cell lipidome and show comparatively higher toxicity than bisphenol A. © 2018 Elsevier Ltd | Anna Marqueño acknowledges a pre-doctoral fellowship BES-2015-074842. Work financed by Ministerio de Ciencia e Innovación , under the project ref. CGL2014-52144-P. Appendix A | Peer reviewed

It is a great challenge to identify the many and varied sources of soil heavy metal pollution. Often little information is available regarding the anthropogenic factors and enterprises that could potentially pollute soils. In this study we use freely available geographical data from a search engine in conjunction with machine learning methodologies to identify and classify potentially polluting enterprises in the Yangtze Delta, China. The data were classified into 31 separate and four integrated industry types by five different machine learning approaches. Multinomial naive Bayesian (NB) methods achieved an accuracy of 87% and Kappa coefficient of 0.82 and were used to classify the geographic data from more than 260,000 enterprises. The relationship between the different industry classes and measurements of soil cadmium (Cd) and mercury (Hg) concentrations was explored using bivariate local Moran's I analysis. The analysis revealed areas where different industry classes had led to soil pollution. In the case of Cd, elevated concentrations also occurred in some areas because of excessive fertilization and coal mining. This study provides a new approach to investigate the interaction between anthropogenic pollution and natural sources of soil heavy metals to inform pollution control and planning decisions regarding the location of industrial sites.

International audience | It is a great challenge to identify the many and varied sources of soil heavy metal pollution. Often little information is available regarding the anthropogenic factors and enterprises that could potentially pollute soils. In this study we use freely available geographical data from a search engine in conjunction with machine learning methodologies to identify and classify potentially polluting enterprises in the Yangtze Delta, China. The data were classified into 31 separate and four integrated industry types by five different machine learning approaches. Multinomial naive Bayesian (NB) methods achieved an accuracy of 87% and Kappa coefficient of 0.82 and were used to classify the geographic data from more than 260,000 enterprises. The relationship between the different industry classes and measurements of soil cadmium (Cd) and mercury (Hg) concentrations was explored using bivariate local Moran's I analysis. The analysis revealed areas where different industry classes had led to soil pollution. In the case of Cd, elevated concentrations also occurred in some areas because of excessive fertilization and coal mining. This study provides a new approach to investigate the interaction between anthropogenic pollution and natural sources of soil heavy metals to inform pollution control and planning decisions regarding the location of industrial sites. (C) 2019 Elsevier Ltd. All rights reserved.

The aim of this study was to determine the amount, composition and origin of plastic debris in one of the world largest river, the Paraná River in Argentina (South America), focusing on the impact of urban rivers, relationships among macro, meso and microplastic, socio-political issues and microplastic ingestion by fish.We recorded a huge concentration of macroplastic debris of domestic origin (up to 5.05 macroplastic items per m2) dominated largely by bags (mainly high- and low-density polyethylene), foodwrapper (polypropylene and polystyrene), foam plastics (expanded polystyrene) and beverage bottles (polyethylene terephthalate), particularly downstream from the confluence with an urban stream. This suggests inadequate waste collection, processing and final disposal in the region, which is regrettably recurrent in many cities of the Global South and Argentina in particular.We found an average of 4654 microplastic fragments m−2 in shoreline sediments of the river, ranging from 131 to 12687 microplastics m−2. In contrast to other studies from industrialized countries from Europe and North America, secondary microplastics (resulting from comminution of larger particles) were more abundant than primary ones (microbeads to cosmetics or pellets to the industry). This could be explained by differences in consumer habits and industrialization level between societies and economies.Microplastic particles (mostly fibres) were recorded in the digestive tract of 100% of the studied Prochilodus lineatus (commercial species).Contrary to recently published statements by other researchers, our results suggest neither macroplastic nor mesoplastics would serve as surrogate for microplastic items in pollution surveys, suggesting the need to consider all three size categories.The massive plastic pollution found in the Paraná River is caused by an inadequate waste management. New actions are required to properly manage waste from its inception to its final disposal.

This is the post-print version of the following article: "Massive plastic pollution in a mega-river of a developing country: Sediment deposition and ingestion by fish (Prochilodus lineatus)", which has been published in final form at https://www.sciencedirect.com/science/article/pii/S0269749119328520 | International audience | The aim of this study was to determine the amount, composition and origin of plastic debris in one of the world largest river, the Paraná River in Argentina (South America), focusing on the impact of urban rivers, relationships among macro, meso and microplastic, socio-political issues and microplastic ingestion by fish.