EPrints IMDEA Water Institute
Not a member yet
1133 research outputs found
Sort by
Freshwater shrimps as sensitive test species for the risk assessment of pesticides in the tropics
No full textThe aquatic risk assessment of pesticides in tropical areas has often been disputed to rely on toxicity data generated from tests performed with temperate species. Given the differences in ecosystem structure between temperate and tropical ecosystems, test species other than those used in temperate regions have been proposed as surrogates for tropical aquatic effect assessments. Freshwater shrimps, for example are important components of tropical freshwater ecosystems, both in terms of their role in ecosystem functioning and their economic value. In the present study, available toxicity data of (tropical and sub-tropical) freshwater shrimps for insecticides and fungicides were compiled and compared with those available for Daphnia magna and other aquatic invertebrates. Freshwater shrimps appeared to be especially sensitive to GABA-gated chloride channel antagonist and sodium channel modulator insecticides. However, shrimp taxa showed a moderate and low sensitivity to acetylcholinesterase inhibiting insecticides and fungicides respectively. Implications for the use of freshwater shrimps in tropical pesticide effect assessments and research needs are discussed
Unpacking factors influencing antimicrobial use in global aquaculture and their implication for management: a review from a systems perspective
No full textGlobal seafood provides almost 20% of all animal protein in diets, and aquaculture is, despite weakening trends, the fastest growing food sector worldwide. Recent increases in production have largely been achieved through intensification of existing farming systems, resulting in higher risks of disease outbreaks. This has led to increased use of antimicrobials (AMs) and consequent antimicrobial resistance (AMR) in many farming sectors, which may compromise the treatment of bacterial infections in the aquaculture species itself and increase the risks of AMR in humans through zoonotic diseases or through the transfer of AMR genes to human bacteria. Multiple stakeholders have, as a result, criticized the aquaculture industry, resulting in consequent regulations in some countries. AM use in aquaculture differs from that in livestock farming due to aquaculture’s greater diversity of species and farming systems, alternative means of AM application, and less consolidated farming practices in many regions. This, together with less research on AM use in aquaculture in general, suggests that large data gaps persist with regards to its overall use, breakdowns by species and system, and how AMs become distributed in, and impact on, the overall social-ecological systems in which they are embedded. This paper identifies the main factors (and challenges) behind application rates, which enables discussion of mitigation pathways. From a set of identified key mechanisms for AM usage, six proximate factors are identified: vulnerability to bacterial disease, AM access, disease diagnostic capacity, AMR, target markets and food safety regulations, and certification. Building upon these can enable local governments to reduce AM use through farmer training, spatial planning, assistance with disease identification, and stricter regulations. National governments and international organizations could, in turn, assist with disease-free juveniles and vaccines, enforce rigid monitoring of the quantity and quality of AMs used by farmers and the AM residues in the farmed species and in the environment, and promote measures to reduce potential human health risks associated with AMR
Detecting the bioaccumulation patterns of chemicals through data-driven approaches
No full textThis work investigates the bioaccumulation patterns of 168 organic chemicals, by comparing their bioconcentration factor (BCF), biomagnification factor (BMF) and octanol-water partitioning coefficient (KOW). It aims to gain insights on the relationships between dietary and non-dietary bioaccumulation, on the effectiveness of KOW and BCF to detect compounds that bioaccumulate through diet, as well as to detect the presence of structure-related accumulation patterns. A linear relationship between logBMF and logKOW was observed (logBMF = 1.14•logBMF – 6.17) up to logKOW ≈ 4, as well as a proportionality between logBMF and logBCF (logBMF = 0.97•logBCF – 4.07) up to a logBCF ≈ 5. 10% of compounds do not satisfy the linear BCF-BMF relationship. The deviations from such linear relationships were further investigated with the aid of a self-organizing map, which allowed us to shed light on some structure-related patterns. Finally, the usage of KOW- and BCF-based thresholds to detect compounds that accumulate through diet lead to many false positives (42%-83% for KOW), and a moderate number of false negatives (up to 5% for both KOW and BCF). These results corroborate the need of using the experimental BMF for hazard assessment practices, as well as of developing of computational tools for BMF prediction
Validation of recycled membranes for treating brackish water at pilot scale
No full textOver the 65% of the installed desalination capacity is related on reverse osmosis (RO) membrane technology. However, membranes have to be replaced when fouling effect is irreversible. In fact, it is estimated that > 840,000 end-of-life RO membranes modules are discarded annually at worldwide scale, mostly in landfills.
In this study, end-of-life RO membranes were recycled at pilot scale by using concentrated solutions of free chlorine. Chemical attack enables the removal of polyamide layer partially or totally, obtaining nanofiltration (NF) and ultrafiltration (UF) membranes, respectively. 5 diverse end-of-life models were tested. Recycled membrane performance (permeability and rejection coefficients) was identified by filtering natural brackish water (BW). Further, validation test were conducted in order to analyze the recycled membrane stability by filtering BW long-term at Cuevas del Almanzora Desalination plant. For this purpose, two real pressure vessels with the capacity of hosting 6 membranes each were adapted. Recycled membranes did not show performance decline after 4 month of filtration. Promising results have been observed. Recycled seawater membranes with properties between RO and NF were validated as potentially fusible membranes. Recycled BW membranes, with high sulphate ion selectivity, were evaluated as a potential alternative of the current NF commercial membranes
An optimized sample treatment method for the determination of antibiotics in seawater, marine sediments and biological samples using LC-TOF/MS
No full textAntibiotics used in marine aquaculture have been reported to accumulate in sediments and non-target aquatic organisms, modifying the biodiversity and the environmental conditions in areas close to the fish farms. Improved analytical methods are required to assess the spread and the impacts of aquaculture antibiotics in the marine environment, as well as to estimate resistance development risks. In this study, we have optimized a method for simultaneous quantitative determination of oxytetracycline, florfenicol and flumequine in marine samples using liquid chromatography coupled to time-of-flight high resolution mass spectrometry (LC-TOF/MS). The method optimization was carried out for seawater, sediment and biological samples (biofilm and two benthic invertebrate species: Gammarus aequicauda and Monodonta articulata). Special attention was paid to the optimization of the extraction and purification steps, testing: liquid-liquid and solid-liquid extractions, the use of silica and other commercial sorbents' clean-up, and single and tandem solid phase extraction procedures. The limits of quantification (MQLs) achieved with the developed method are 0.1–0.5 μg L-1 in seawater; 1–5 μg kg−1 in marine sediments; 5–25 μg kg−1 in biofilm; and 100–500 μg kg−1 in invertebrates, with good accuracy and precision. Method recoveries in spiked samples are 65–120% in seawater and sediment samples, and 63–110% in the biological samples. The method has been successfully implemented for the determination of antibiotic concentrations in sediment and invertebrate samples collected from a Mediterranean bay in south-east Spain. These represent significant advances in the analysis of antibiotics in environmental samples, especially for wild marine taxa, and attend for a proper assessment of the environmental fate and side effects of aquaculture antibiotics in the marine environment
Effects of imidacloprid and a neonicotinoid mixture on aquatic invertebrate communities under Mediterranean conditions
No full textNeonicotinoid insecticides are considered contaminants of concern due to their high toxicity potential to non-target terrestrial and aquatic organisms. In this study we evaluated the sensitivity of aquatic invertebrates to a single application of imidacloprid and an equimolar mixture of five neonicotinoids (imidacloprid, acetamiprid, thiacloprid, thiamethoxam, clothianidin) using mesocosms under Mediterranean conditions. Cyclopoida, Cloeon dipterum and Chironomini showed the highest sensitivity to neonicotinoids, with calculated NOECs below 0.2 μg/L. The sensitivity of these taxa was found to be higher than that reported in previous studies performed under less warm conditions, proving the high influence of temperature on neonicotinoid toxicity. The short-term responses of the zooplankton and the macroinvertebrate communities to similar imidacloprid and neonicotinoid mixture concentrations were very similar, suggesting that the concentration addition model can be used as a plausible hyphotesis to assess neonicotinoid mixture effects in aquatic ecosystems. Long-term mixture toxicity assessments, however, should consider the fate of the evaluated substances in the environment of concern. As part of this study, we also demonstrated that Species Sensitivity Distributions constructed with chronic laboratory toxicity data and calculated (multi-substance) Potentially Affected Fractions provide an accurate estimation to asssess the ecotoxicologial risks of imidacloprid and neonicotinoid mixtures to aquatic invertebrate species assemblages
Diversity and enzymatic potentialities of Bacillus sp. strains isolated from a polluted freshwater ecosystem in Cuba
No full textGenotypic and phenotypic characterization of Bacillus spp. from polluted freshwater has been poorly addressed. The objective of this research was to determine the diversity and enzymatic potentialities of Bacillus spp. strains isolated from the Almendares River. Bacilli strains from a polluted river were characterized by considering the production of extracellular enzymes using API ZYM. 14 strains were selected and identified using 16S rRNA, gyrB and aroE genes. Genotypic diversity of the Bacillus spp. strains was evaluated using pulsed field gel electrophoresis. Furthermore, the presence of genetic determinants of potential virulence toxins of the Bacillus cereus group and proteinaceous crystal inclusions of Bacillus thuringiensis was determined. 10 strains were identified as B. thuringiensis, two as Bacillus megaterium, one as Bacillus pumilus and one as Bacillus subtilis. Most strains produced proteases, amylases, phosphatases, esterases, aminopeptidases and glucanases, which reflect the abundance of biopolymeric matter in Almendares River. Comparison of the typing results revealed a spatio-temporal distribution among B. thuringiensis strains along the river. The results of the present study highlight the genotypic and phenotypic diversity of Bacillus spp. strains from a polluted river, which contributes to the knowledge of genetic diversity of Bacilli from tropical polluted freshwater ecosystems