Organisms Of Different Trophic Levels Research Articles

The usefulness of ecotoxicological tools to improve the assessment of water bodies in a climate change reality

This study aimed to analyse the added value of using ecotoxicological tools to complement and improve the assessment of natural water bodies status, in situations of climate change, with a higher frequency of extreme events as floods or droughts.Four water bodies of streams in the Guadiana Basin (Álamos, Amieira, Lucefécit, Zebro) were studied in 2017 and 2018 and classified based on the Water Framework Directive (WFD) parameters: Biological Quality Element – Phytobenthos (diatoms), General chemical and physicochemical elements, Specific pollutants, and Priority Substances. Complementarily, bioassays (including lethal and sublethal parameters) were carried out with organisms of different trophic levels: (i) the bacteria Aliivibrio fischeri; (ii) the microalgae Pseudokirchneriella subcapitata; (iii) the crustaceans Daphnia magna, Thamnocephalus platyurus and Heterocypris incongruens. A classification system with 5 scores was developed, permitting to classify water bodies from non-toxic (EC50 > 100 %; growth and feeding rate > 80 %; blue) to highly toxic (EC50 < 10 %; growth and feeding rate < 10 %; red). The comparison between the classification based on the WFD parameters and on ecotoxicological endpoints showed similar results for 71 % of the samples, and significant positive Pearson correlations were detected between the diatom-based Specific Polluosensitivity Index (SPI) and EC50V.fisheri, the algae growth rate and Shannon diversity index. These results indicate that when the biological quality elements cannot be used (namely under drought or flooding conditions) the application of ecotoxicological bioassays may be a good alternative. Further, when ecotoxicological parameters were included, an increase of worse classifications (Bad and Poor) was observed, revealing an improvement in the sensitivity of the classification, mainly in presence of specific and priority substances. So, the ecotoxicological analysis appears to provide useful information regarding the potential presence of both known and unknown contaminants at concentrations that cause biological effects (even within the WFD limits), in agreement with several authors that have already suggested its use in biomonitoring.

Computational modeling (in silico) methods combined with ecotoxicological experiments (in vivo) to predict the environmental risks of an antihistamine drug (loratadine)

This study employed computational modeling (in silico) methods, combined with ecotoxicological experiments (in vivo) to predict the persistence/biodegradability, bioaccumulation, mobility, and ecological risks of an antihistamine drug (Loratadine: LOR) in the aquatic compartment. To achieve these goals, four endpoints of the LOR were obtained from different open-source computational tools, namely: (i) “STP total removal”; (ii) Predicted ready biodegradability; (iii) Octanol-water partition coefficient (KOW); and (iv) Soil organic adsorption coefficient (KOC). Moreover, acute and chronic, ecotoxicological assays using non-target freshwater organisms of different trophic levels (namely, algae Pseudokirchneriella subcapitata; microcrustaceans Daphnia similis and Ceriodaphnia dubia; and fish Danio rerio), were used to predict the ecological risks of LOR. The main results showed that LOR: (i) is considered persistent (after a weight-of-evidence assessment) and highly resistant to biodegradation; (ii) is hydrophobic (LOG KOW = 5.20), immobile (LOG KOC = 5.63), and thus, it can potentially bioaccumulate and/or can cause numerous deleterious effects in aquatic species; and (iii) after ecotoxicological evaluation is considered “toxic” and/or “highly toxic” to the three trophic levels tested. Moreover, both the ecotoxicological assays and risk assessment (RQ), showed that LOR is more harmful for the crustaceans (RQcrustaceans = moderate to high risks) than for algae and fish. Ultimately, this study reinforces the ecological concern due to the indiscriminate disposal of this antihistamine drug in worldwide aquatic ecosystems.

ИНСТРУМЕНТАЛЬНЫЕ МЕТОДЫ БИОТЕСТИРОВАНИЯ ВОД, ПОЧВ, ГРУНТОВ И ОТХОДОВ

The paper presents the main achievements of the Siberian Federal University in the field of environmental pollution biomonitoring. Methods for increasing the reproducibility of bioassay results by using a specialized instrumental set, maintaining controlled standard conditions, and automating processes are shown. Some approaches to solving the problems of insufficient sensitivity of test objects to pollutants and the long duration and high labor intensity of bioassays are presented. The described methods make it possible to study toxicity of various media (water, soil, waste), as well as to evaluate the impact of pollutants on organisms of different trophic levels. The issues of developing and implementing rapid methods for detecting toxicity of the analyzed media are considered.

Chemometers: an integrative tool for chemical assessment in multimedia environments.

We propose novel chemometers - passive equilibrium samplers of, e.g., silicone - as an integrative tool for the assessment of hydrophobic organic compounds in multimedia environments. The traditional way of assessing levels of organic pollutants across different environmental compartments is to compare the chemical concentration normalized to the major sorptive phase in two or more media. These sorptive phases for hydrophobic organic compounds differ between compartments, e.g., lipids in biota and organic carbon in sediments. Hence, comparability across media can suffer due to differences in sorptive capacities, but also extraction protocols and bioavailability. Chemometers overcome these drawbacks; they are a common, universal and well-defined polymer reference phase for sampling of a large range of nonpolar organic pollutants in different matrices like biota, sediment and water. When bringing the chemometer into direct contact with the sample, the chemicals partition between the sample and the polymer until thermodynamic equilibrium partitioning is established. At equilibrium, the chemical concentrations in the chemometers can be determined and directly compared between media, e.g., between organisms of different trophic levels or inhabiting different areas, between organs within an organism or between biotic and abiotic compartments, amongst others. Chemometers hence allow expressing the data on a common basis, as the equilibrium partitioning concentrations in the polymer, circumventing normalizations. The approach is based on chemical activity rather than total concentrations, and as such, gives a measure of the "effective concentration" of a compound or a mixture. Furthermore, chemical activity is the main driver for partitioning, biouptake and toxicity. As an additional benefit, the extracts of the chemometers only require limited cleanup efforts, avoiding introduction of a bias between chemicals of different persistence, and can be submitted to both chemical analysis and/or bioanalytical profiling.

Development of integrated multitrophic aquaculture–based cage rearing system in an underutilized fishing port and its application in marine stock enhancement

Human activity and global climate change have severely affected marine ecosystems and fishery resources. Habitat conservation and stock enhancement are considered effective methods. Moreover, with the gradual disappearance of fishery resources, fishing ports have become underutilized spaces. Currently, 73 of the 221 fishing ports in Taiwan are underutilized. Therefore, we, for the first time, developed an integrated multitrophic aquaculture (IMTA)-based cage rearing system suitable for stock enhancement and applied it in an optimal underutilized fishing port after the site evaluation and selection of 17 potential fishing ports fishing. We further tested that hypothesis that hatchery-produced organisms can be reared and monitored appropriately in this cage rearing system with good survival and growth as well as less environmental impact and handling stress. Through the collocation of various release organisms of different trophic levels, the cage rearing system can reduce environmental impacts as evidenced by the steady water quality (stable pH and undetectable levels of ammonia nitrogen, nitrates, and nitrites). As for the fish welfare, this semiartificial rearing system could also reduce the discomforts of hatchery-produced organisms after transportation and facilitate their adaptations to the released environments as evidenced by positive growth and high survival rates (94%–98%). The cultured and naturally grown shellfish and algae on the cage nets could provide habitats for hatchery-produced and wild organisms that facilitate habitat conservation and stock enhancement. Taken together, we have demonstrated that it is feasible to implement this novel IMTA-based cage rearing system in an underutilized fishing port required for marine stock enhancement.

Effects of mycogenic silver nanoparticles on organisms of different trophic levels

Biogenic silver nanoparticles (AgNPs) are considered a promising alternative to their synthetic versions. However, the environmental impact of such nanomaterials is still scarcely understood. Thus, the present study aims at assessing the antimicrobial action and ecotoxicity of AgNPs biosynthesized by the fungus Aspergillus niger IBCLP20 towards three freshwater organisms: Chlorella vulgaris, Daphnia similis, and Danio rerio (zebrafish). AgNPs IBCLP20 showed antibacterial action against Klebsiella pneumoniae between 5 and 100 μg mL−1, and antifungal action against Trichophyton mentagrophytes in concentrations ranging from 20 to 100 μg mL−1. The cell density of the microalgae Chlorella vulgaris decreased 40% after 96 h of exposure to AgNPs IBCLP20, at the highest concentration analysed (100 μg L−1). The 48 h median lethal concentration for Daphnia similis was estimated as 4.06 μg L−1 (2.29–6.42 μg L−1). AgNPs IBCLP20 and silver nitrate (AgNO3) caused no acute toxicity on adult zebrafish, although they did induce several physiological changes. Mycosynthetized AgNPs caused a significant increase (p < 0.05) in oxygen consumption at the highest concentration studied (75 μg L−1) and an increase in the excretion of ammonia at the lower concentrations, followed by a reduction at the higher concentrations. Such findings are comparable with AgNO3, which increased the oxygen consumption on low exposure concentrations, followed by a decrease at the high tested concentrations, while impairing the excretion of ammonia in all tested concentrations. The present results show that AgNPs IBCLP20 have biocidal properties. Mycogenic AgNPs induce adverse effects on organisms of different trophic levels and understanding their impact is detrimental to developing countermeasures aimed at preventing any negative environmental effects of such novel materials.

Micro(nano)plastics and plastic additives effects in marine annelids: A literature review

Plastic debris are dispersed in the marine environment and are consequently available to many organisms of different trophic levels, including sediment-dwelling organisms such as polychaetae. Plastic degradation generates micro (MPs) and nanoplastics (NPs) and as well as releases bounded plastic additives, increasing the ecotoxicological risk for marine organisms. Therefore, this review summarizes current knowledge on the accumulation and effects of MPs and NPs and plastic additives in polychaetes, derived from laboratory and field evidences. Thirty-six papers (from January 2011 to September 2021) were selected and analysed: about 80% of the selected works were published since 2016, confirming the emerging role of this topic in environmental sciences. The majority of the analysed manuscripts (68%) were carried out in the laboratory under controlled conditions. These studies showed that polychaetes accumulate and are responsive to this contaminant class, displaying behavioural, physiological, biochemical and immunological alterations. The polychaetes Hediste diversicolor and Arenicola marina were the most frequent used species to study MPs, NPs and plastic additive effects. The consideration of field studies revealed that MP accumulation was dependent on the plastic type present in the sediments and on the feeding strategy of the species. Polychaetes are known to play an important role in coastal and estuarine food webs and exposure to MPs, NPs and plastic additives may impair their behavioural, physiological, biochemical and immunological responses. Thus, the estimated global increase of these contaminants in the marine environment could affect the health of these benthic organisms, with consequences at population and ecosystem levels.

An Integrated Monitoring Approach to the Evaluation of the Environmental Impact of an Inshore Mariculture Plant (Mar Grande of Taranto, Ionian Sea).

Simple SummaryThe importance of aquaculture for providing animal proteins to a steeply increasing world population is growing. Despite the many benefits from this practice, there are also many constraints. Among them, the eutrophication of seawater and unsustainability are of the utmost importance. Integrated multitrophic aquaculture (IMTA), consisting of the co-farming of organisms of different trophic levels, was conceived to overcome these problems, and it is still developing to reach sustainable practices. In the Taranto seas (southern Italy, Mediterranean Sea), the first attempt of an IMTA plant with fish, mussels, polychaetes, sponges, and seaweeds started within the framework of the REMEDIA-LIFE project. This plant was arranged in a pre-existing fish farm where the European seabass Dicentrarchus labrax and the sea bream Sparus aurata are bred in net cages. Here, we report the results of the ex-ante evaluation of the trophic conditions of the seawater around the plant, which is useful for assessing the bioremediation effectiveness of the IMTA action after its implementation.The results of an ex-ante survey aiming to assess the impact of a fish farm in the Mar Grande of Taranto (southern Italy, Mediterranean Sea) on the surrounding environment are reported. There, the implementation of an innovative IMTA plant was planned, with the goals of environment bioremediation and commercially exploitable biomass production. Analyses were conducted in February and July 2018. Both seawater and sediments were sampled at the four corners of the fish farm to detect the existing biological and physico-chemical features. The investigation was performed to identify the best area of the farming plant for positioning the bioremediating system, but also to obtain a data baseline, to compare to the environmental status after the bioremediating action. Data were also analyzed by canonical analysis of principal coordinates (CAP). All the measurements, in particular, microbiology and macrobenthic community characterization using AZTI’s Marine Biotic Index (AMBI) and the Multivariate-AMBI (M-AMBI) indices, suggest that the effect of fish farm waste was concentrated and limited to a small portion of the investigated area in relation to the direction of the main current. A site named A3, which was found to be the most impacted by the aquaculture activities, especially during the summer season, was chosen to place the bioremediation system.

Textile-effluent treatment using Aloe vera mucilage as a natural coagulant prior to a photo-Fenton reaction

In this study, the mucilage of Aloe vera was used as a new auxiliary coagulant in pre-treatment using a combined system based on the photo-Fenton (PF) process for the treatment of textile effluents. Coagulation–flocculation (CF) using a combination of coagulants showed better performance in the elimination of turbidity, chemical oxygen demand (COD), dissolved organic carbon (DOC), and natural organic matter (NOM) when compared with a single inorganic coagulant. In addition, the combination of coagulants allowed a 28% reduction in the concentration of the inorganic coagulant used. To remove the dissolved and recalcitrant matter after CF, the pretreated effluent was subjected to a PF process that is efficient in the degradation and mineralization of dissolved organic compounds; this resulted in the elimination of 82.48% of COD, 80.34% of DOC, and 79.65% of NOM, as well as the formation of inorganic ions. The toxicity of the samples was evaluated base on three organisms of different trophic levels: Lactuca sativa, Artemia salina, and Eisenia fetida. The results showed that the samples treated by CF or CF/PF were non-toxic to A. salina and E. fetida. However, in the L. sativa bioassay, the root-growth parameter revealed toxicity in the effluents before and after treatment, excluding the untreated effluents with doses of 100 and 200 mL L-1 and the effluent with a dose of 100 mL L-1 treated by the CF process.

Occurrence of rare earth elements in fledgelings of Thalasseus sandvicensis.

Rare Earth Elements (REEs) are increasingly exploited for crucial new technologies, and their massive use in the past decades has significantly increased their environmental concentrations. Although their effects have been extensively studied in vitro and in vivo in model species, little is known of their accumulation and potential toxic effects in wildlife, including waterbirds. In the present work, we measured the concentrations of REEs in feathers of young Sandwich tern (Thalasseus sandvicensis) about 16-20 days old to assess whether the accumulation of these elements may be a concern in Venice's Lagoon, one of the most important wetlands of the Mediterranean area for breeding and migrating birds. The REE concentrations detected in the Sandwich tern were the highest among those reported in the literature for bird's feathers (940.9±223.0ngg-1), although in the study area industrial activities related to REEs mining, processing and disposal are absent. In particular, Lanthanum (La) was more abundant in the feathers than other REEs and accounted for 73-97% of total REEs detected. Analysis of bird's food indicated that diet is a relevant route of exposure to REEs for young terns; however, concentration in fishes are relevantly higher than in the feathers for all REEs other than La. The study evidenced the need to collect more information concerning the occurrence of REEs both in the abiotic matrices (i.e. water and sediments) and in living organisms of different trophic levels to improve the general knowledge concerning the fate of REEs in the aquatic ecosystems.

Ecotoxicological assessment of amoxicillin trihydrate: Stability, solubility, and acute toxicity for Oreochromis niloticus, Lemna minor, and Daphnia magna

Among the different pharmaceuticals present in water as micro-contaminants, antibiotics are considered an important risk group for the aquatic ecosystem, since their increasing use in human and veterinary medicine could affect the diversity of microorganism communities. This study aims to classify the acute toxicity of amoxicillin trihydrate for organisms of different trophic levels of aquatic biological chains, represented by Oreochromis niloticus (fish), Lemna minor (macrophyte) and Daphnia magna (microcrustacean). For this purpose, amoxicillin trihydrate degradability in water as well as changes in physicochemical characteristics are focused herein. Initial tests were performed to validate the assay, including drug dissolution in M4 medium, drug degradation in various culture media, sensitivity of experimental organisms as well as preliminary drug intoxication test. Upon validation tests, 2.6 g L−1 amoxicillin was determined as the concentration to evaluate the toxicity factor. Static (48 h) and semi-static (168 h) assays were performed. Therefore, amoxicillin trihydrate did not have an acute toxic effect at the concentration of 2.6 g L−1 under the experimental conditions applied to the species Lemna minor, Daphnia magna and Oreochromis niloticus. demonstrating the very low acute toxicity to aquatic organisms at different trophic levels.

Multimedia Distribution Characteristics and Risk Assessment of 22 PPCPs in the Water Environment of Qingpu District, Yangtze River Delta Demonstration Area

In this study, 50 surface water and sediment samples were collected from 25 sampling points in Qingpu District (including Taipu River basin, Jinze Reservoir, and Qingxi country park) in the Yangtze River Delta integration demonstration area, and 22 pharmaceuticals and personal care products (PPCPs) in the samples were analyzed using high-performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS). The distribution characteristics, sources, and influencing factors of targeted PPCPs in the study area were studied in detail. The ecological and health risks of the target PPCPs were evaluated using the quotients method. The results showed that a total of 19 PPCPs were detected in the surface water and sediment samples from 25 sampling points in Qingpu District, with total concentrations ranging from 0.06 to 178.67 ng·L-1 and 0.07 to 37.68 ng·g-1, respectively. The average value of sulfachloropyridazine (SCP) in the surface water was the highest with a concentration of 129.54 ng·L-1, whereas the average value of sulfamethoxazole (SMX) in the sediment was the highest with a concentration of 70.62 ng·g-1. The spatial distribution of the total amount of PPCPs showed a trend of Qingxi country park > Jinze Reservoir > Taipu River basin. Principal component analysis showed that the main sources of pollution were animal antibiotics used in aquaculture and the discharge of domestic sewage. There was a significant correlation between lg Koc and lg Kd (P<0.05), indicating that the organic carbon plays an important role in the distribution of the target PPCPs in water and sediments. The ecological risk assessment results revealed that the fungicides (TCC and TCS) in the surface waters showed a moderate risk to aquatic organisms of different trophic levels. The Qingxi country park and Jinze Reservoir were the regions with the highest ecological risks of PPCPs in surface water and sediment. The health risk entropy (HQ) of people of all age groups exposed through drinking was less than 1; however, with the continuous emission and accumulation of PPCPs, the pollution control of PPCPs in the environment still requires further attention.

Polystyrene Nanoplastics Inhibit the Transformation of Tetrabromobisphenol A by the Bacterium Rhodococcus jostii.

Microplastics (MPs) and nanoplastics (NPs) in the environment pose significant risks to organisms of different trophic levels. While the toxicity of MPs and NPs have been extensively investigated, it remains unknown whether these particles affect microbial transformation of organic pollutants. Here, we show that 20 and 100 nm polystyrene NPs (PS-NPs) can inhibit the transformation of tetrabromobisphenol A (TBBPA) by Gram-positive bacterium Rhodococcus jostii in a concentration-dependent manner. We found that smaller PS-NPs were more inhibitory than larger ones and that both PS-NPs affected biotransformation in several ways. PS-NPs adsorbed TBBPA on their surface and reduced the bioavailable concentration of TBBPA for transformation by R. jostii. Furthermore, PS-NPs induced oxidative stress, increased membrane permeability, and downregulated O-methyltransferase enzymes that transform TBBPA into their methylated derivatives. Our results demonstrate that PS-NPs can impact microbial transformation of organic pollutants, and these effects should be accounted for in future environmental risk assessments.

Ecotoxicity of losartan potassium in aquatic organisms of different trophic levels

The intensive use of the antihypertensive losartan potassium (LOS) has culminated in its high occurrence in aquatic environments. However, insufficient studies had investigated its effects in non-target organisms. In this study, ecotoxicity of LOS was assessed in aquatic organisms from distinct trophic levels (Desmodesmus subspicatus, Daphnia magna, and Astyanax altiparanae). Genotoxicity was assessed by the comet assay in D. magna and A. altiparanae, and biochemical biomarkers for the fish. LOS was more toxic to D. subspicatus (EC50(72h) = 27.93 mg L−1) than D. magna (EC50 = 303.69 mg L−1). Subsequently, this drug showed to induce more DNA damage in D. magna than A. altiparanae, when exposed to 2.5 mg L−1. No significant stress responses were observed by the fish biomarkers, suggesting that higher trophic levels organisms are more tolerant to LOS toxicity. LOS showed relatively low toxic potential for a short period of exposure, but with different patterns of toxicity for the organisms from distinct trophic levels, contributing to further risk assessment of LOS.

Face masks as a source of nanoplastics and microplastics in the environment: Quantification, characterization, and potential for bioaccumulation

Billions of disposable face masks are consumed daily due to the COVID-19 pandemic. The role of these masks as a source of nanoplastics (NPs) and microplastics (MPs) in the environment has not been studied in previous studies. We quantified and characterized face mask released particles and evaluated their potential for accumulation in humans and marine organisms. More than one billion of NPs and MPs were released from each surgical or N95 face mask. These irregularly-shaped particles sized from c. 5 nm to c. 600 μm. But most of them were nano scale sized <1 μm. The middle layers of the masks had released more particles than the outer and inner layers. That MPs were detected in the nasal mucus of mask wearers suggests they can be inhaled while wearing a mask. Mask released particles also adsorbed onto diatom surfaces and were ingested by marine organisms of different trophic levels. This data is useful for assessing the health and environmental risks of face masks.

Potential Toxic Effects of Airport Runoff Water Samples on the Environment

Despite the positive aspects of the intensive development of aviation, airports are considered large-scale polluters. Pollution caused by runoff water (stormwater) is one of the major problems related to airport operations. The aim of this study was to characterize the potential toxic impact on aquatic life from runoff water discharges from four international airports in Europe. Samples of stormwater were collected at airports with different capacities of passenger movement in four seasons of the year from 2011 to 2013. Within the ecotoxicological analyses, a battery of biotests incorporating organisms of different trophic levels (Microtox® test, Thamnotoxkit F™) were used. A relatively high number of runoff water samples collected at the investigated airports in Europe was recorded as having very high acute hazard (16.8%), acute hazard (27.7%), and slight acute hazard (18.1%) levels. The results of the research indicate that winter and autumn present a greater toxic threat than the rest of the year. The highest number of toxic samples was observed for samples collected in the de-icing area, the runway and the vicinity of airport terminals. The ecotoxicological assessment applied in this research can be used as a tool for assessing the environmental effect of airports.

Glyphosate concentrations in global freshwaters: are aquatic organisms at risk?

Glyphosate is the most used herbicide worldwide. Many studies have reported glyphosate risks to aquatic organisms of different trophic levels. Moreover, evidence suggests flaws in countries' legislation that may imply the non-protection of aquatic species exposed to glyphosate. Therefore, we aimed to investigate glyphosate concentrations in freshwater ecosystems worldwide based on a systematic literature review, to discuss the results considering each country's legislation, and to assess the relative tolerance and risk for aquatic species. Only articles providing in situ concentrations of glyphosate in freshwater systems were included in our study. In total, 73 articles met the inclusion criteria and were used in our analysis. The studies comprised freshwater ecosystems from 21 countries. Most countries evaluated (90%) did not have restrictive legislation for aquatic glyphosate concentrations, resulting in a potential non-protection of aquatic organisms. Glyphosate may pose a moderate to high risk in 95% of the countries investigated, reaching a maximum concentration of 105 mg L-1. Additionally, the risk analysis showed that glyphosate concentrations below 0.1 μg L-1 represent a low risk, whereas glyphosate concentrations above 1 μg L-1, which is below the limit established by some countries' legislation, represent a high risk to aquatic organisms. Therefore, we strongly recommend a revision of the countries' legislation for glyphosate concentration in freshwater systems.

Microplastic characteristics in organisms of different trophic levels from Liaohe Estuary, China

Microplastics are a growing concern globally due to their small size and easy ingestion by terrestrial and aquatic organisms, resulting in potential adverse impacts on wildlife. However, current data regarding microplastics in wild organisms in different trophic levels is limited. This study investigated microplastic characteristics, including their abundance, size, shape and polymer type, in estuarine invertebrates and vertebrates. Resultantly, polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) were the predominant microplastics found, as confirmed by a Fourier transform infrared spectrometer (FT-IR). An average microplastic abundance of 0.83 ± 0.99 to 3.87 ± 2.18 items/individual was detected across all species, including sandworm, mollusks, crustacean and fish, but they were not found in all individuals. Microplastics ranged from 52 μm to 5392 μm in size, and the shapes were consisted of fiber, fragment, and pellet. Moreover, the detection ratio (91.95%) and abundance (3.34 ± 2.17 items/individual) of microplastics in fish were significantly higher than in sandworm (42.86%, 0.88 ± 1.04 items/individual), mollusks (66.97%, 1.42 ± 1.41 items/individual) and crustaceans (66.66%, 1.33 ± 1.32 items/individual) (p < 0.05). Furthermore, a positive relationship was identified between microplastic abundance and the trophic level of organisms. These findings imply that microplastics might transfer along the food chain and accumulate at organisms in higher trophic levels.

Geochemical and ecotoxicological evaluation of sediments of a semiarid estuary on the northeast of Brazil (Natal / RN)

The Jundiaí-Potengi Estuary (JPE), northeast of Brazil, suffers from intense degradation due to anthropogenic pollution from different sources, including several punctual treated and untreated domestic sewage discharges. To evaluate the estuary surface sediment quality near the outlet of a wastewater treatment plant (WWTP), five sampling points were selected. Four campaigns were performed on dry and rainy seasons of the years 2015 and 2016. The sediment samples were submitted to chronic ecotoxicological tests with Nitocra sp., and to metals, granulometry, and total organic matter analysis. The geochemical data were analyzed through enrichment indexes and, multivariate analysis, was performed integrating the ecotoxicological data. The sediment did not display toxicity to Nitocra sp. however, some metals’ concentration (Mn, Pb, Cu, Ni, and Cd) exceeded the limits established by Brazilian legislation. In general, the concentration of the analyzed metals doubled from rainy season to dry season. Considering our findings, we suggest quantifying other classes of contaminants and conducting studies on the bioavailability of metals in JPE, as well as using other organisms of different trophic levels in ecotoxicity tests.

Application of ecotoxicological bioassays to assess the water quality in the Cañuelas stream (Buenos Aires, Argentina)

La inclusión de los análisis ecotoxicológicos en los estudios ambientales resulta indispensable ya que aporta información sobre los efectos que los contaminantes puedan causar en los organismos expuestos y en los ecosistemas receptores. El objetivo del trabajo fue evaluar la calidad del agua en la cuenca del arroyo Cañuelas (Buenos Aires, Argentina) a partir de determinaciones fisicoquímicas y de bioensayos ecotoxicológicos estandarizados en diferentes niveles tróficos con los organismos: Pseudokirchneriella subcapitata, Lactuca sativa y Caenorhabditis elegans. Las muestras fueron extraídas de cuatro puntos de muestreo representativos a lo largo del cauce de los arroyos Cañuelas y Navarrete. P. subcapitata y la raíz de L. sativa presentaron los valores más altos de inhibición del crecimiento en los puntos de muestreo coincidentes con un mayor deterioro de la calidad del agua de acuerdo con los niveles propuestos por la normativa local. Contrariamente, C. elegans reveló toxicidad en muestras cuyos parámetros fisicoquímicos cumplieron con la normativa vigente. Los resultados de este trabajo respaldan la necesidad de incorporar una batería de bioensayos ecotoxicológicos que complementen los análisis fisicoquímicos y contribuyan a una mejor gestión de los recursos hídricos.