Aquatic Samples Research Articles

Visual LAMP method for the detection of Vibrio vulnificus in aquatic products and environmental water

BackgroundA visual, rapid, simple method was developed based on a loop-mediated isothermal amplification (LAMP) assay to detect Vibrio vulnificus in aquatic products and aquaculture waters.ResultsGenomic DNA was extracted from Vibrio vulnificus using the boiling method, and optimized primers were used to detect the gyrB gene using a visual LAMP method. The sensitivity of the assay was 10 fg/μL, and the obtained results were stable and reliable. Out of 655 aquatic product samples and 558 aquaculture water samples, the positive rates of Vibrio vulnificus detection were 9.01% and 8.60%, respectively, which are markedly higher than those of the traditional culture identification methods.ConclusionThe relatively simple technical requirements, low equipment cost, and rapid detection make the visual LAMP method for the detection of Vibrio vulnificus a convenient choice for field detection in the aquaculture industry.

Synergistically improved electrochemical performance by the assembly of nanosized praseodymium tungstate on reduced graphene oxide for the detection of dimetridazole in biological and aquatic samples

Over the years, widely increasing overdose and improper disposal of drugs are harmful to public health and the ecosystem. Herein, the nanostructured praseodymium tungstate decorated on reduced graphene oxide (PW NPs/R-GO) composite was used for the detection of antiprotozoal drug dimetridazole (DMZ). The nanostructured PW NPs were prepared by solvent evaporation from peroxo-tungstic acid and the composite of PW NPs/R-GO was assembled through a facile ultrasonication method. Under the suitable circumstance, the fabricated PW NPs/R-GO/GCE sensor displays outstanding electrocatalytic performance towards DMZ, and significantly, provided a higher reduction response than PW NPs/GCE, R-GO/GCE, and bare GCE. This fabricated sensor achieved a nanomolar detection limit (1.2 nM) and a wide linear range (0.001–965 µM) of DMZ by using highly sensitive DPV techniques. The constructed sensor endows excellent repeatability, reproducibility, selectivity, and storage stability performance. However, the practical capability of constructed PW NPs/R-GO/GCE sensor was successfully verified in biological, and environmental fluids to achieve a good recovery result. Therefore, this work endows a new perception for real-time sensing of DMZ in biological and aquatic samples.

An amperometric electrochemical sensor based on hierarchical dual- microporous structure polypyrrole nanoparticles for determination of pyrogallol in the aquatic environmental samples

Pyrogallol (PY) is commonly found as inherent toxicity of industrial effluents which easily enter to the aquatic environment; owing to its oxygen free radicals which causes several health issues. We report a highly sensitive and selective pyrogallol (PY) sensor using hierarchical dual-microporous polypyrrole nanoparticle-modified screen-printed carbon electrode (MPNPs/SPCE). The proposed electrode material for the cost-effective and rapid estimation of PY in the environmental water samples. Hierarchical dual-microporous polypyrrole nanoparticles were prepared through the simple chemical polymerization of pyrrole using Pluronic F-127 as the surfactant. The MPNPs possess well-defined dual micropore (∼0.52 and ∼ 0.67 nm) and a large BET surface area (183 m2/g). The electro-oxidation behavior of PY was examined by cyclic voltammetry and amperometric technique. Hierarchical structure with dual-microporous networks, and large specific surface area of MPNPs were assumed to be greatly enhanced the adsorption rate and a fast facilitate ion transfer for PY sensor. Owing to the effective coupling of hydrogen bonding (interaction between –OH group of PY and –NH group of polymer chain) and π -π interactions (between PPy rings and the PY aromatic rings) can offer more accessible electrochemical active sites and electrolyte/electrode contact interfaces for rapid electro-oxidation response. As a result, wide linear range (0.05–130 μM), good detection limit (0.03 μM), and high sensitivity (1.213 μA μM−1 cm−2) toward PY surpass those of other modified electrodes. Furthermore, MPNPs/SPCE system exhibited desirable selectivities, good steady stabilities, and reproducibilities as PY sensors. Real domestic, industrial, and sewage environmental water samples were analyzed, with quantification data compared with those obtained by HPLC.

Aggregation-induced emission luminogens-encoded microspheres preparation and flow-through immunoaffinity chromatographic assay development for microcystin-LR analysis

Despite decades of efforts, we are faced with the daunting task of on-site ultratrace environmental toxins detecting, especially the microcystins caused by water bloom. In this work, a novel fluorescent microsphere-based flow-through immunoaffinity chromatographic assay has been designed for detecting ultratrace microcystin-LR in water and aquatic products. The aggregation-induced emission luminogens were encapsulated into fluorescent microspheres to ensure microcystin-LR quantitation with a whole analytical time of less than 30 min. Furthermore, the colorimetric images were captured and quantitatively analyzed, which offered a limit of detection at 0.217 pg/mL and a limit of quantitation at 0.362 pg/mL in water and aquatic muscle samples. The developed immunoassays provide average recovery ranging from 79.1 % to 95.7 %, with relative standard deviations less than 13.4 %. Thus, the validated flow-through immunoaffinity chromatographic assay is an easy-to-use alternative for on-site screening of microcystin-LR in water and aquatic samples at picogram levels.

DNA Barcoding Takes Bioassessment Further: New Distribution Records for Aquatic Macroinvertebrates from Alaskan National Parks

DNA barcoding was applied to select macroinvertebrates from aquatic bioassessment samples collected from National Parks and Preserves in Alaska, USA. The finer taxonomic resolution provided by barcoding revealed the presence of 28 insect species previously unreported from Alaska; 21 of these are also new records for the USA, and 7 are new records for North America, excluding Greenland. The new records are distributed among Diptera: Ceratopogonidae (1), Chironomidae (20), Limoniidae (1), and Tipulidae (1); Ephemeroptera: Baetidae (2); and Trichoptera: Apataniidae (1), Goeridae (1), and Leptoceridae (1).

Well water sources simultaneous contamination with Cryptosporidium and Acanthamoeba in East-Southeast Asia and Acanthamoeba spp. in biofilms in the Philippines.

Cryptosporidium is the leading agent of waterborne parasitic protozoan outbreaks and is the second leading cause of infant mortality due to diarrhoea worldwide. Acanthamoeba spp. causes Acanthamoeba keratitis (AK) and a life-threatening condition known as granulomatous amoebic encephalitis (GAE). The present study aimed to assess the water quality of an indigenous and a rural community for waterborne parasitic protozoan contamination. Aquatic samples (n = 22) were processed by filtration of 500 mL portion through a 1.2 μm pore size glass microfiber filter and eluted for light microscopy, culture in non-nutrient agar, and PCR analysis. Overall, 36% (8/22) of the investigated aquatic samples were positive for either Cryptosporidium spp. oocysts (13%; 3/22) or Acanthamoeba spp., (36%; 8/22) or both (13%; 3/22). Cryptosporidium spp. oocysts were detected in 27% (3/11) of wet season samples only while Acanthamoeba spp. were detected in 18% (2/11) and 55% (6/11) of wet and dry season samples, respectively. Subsequently, molecular detection for Acanthamoeba species identified A. lenticulata and A. hatchetti with 98-99% BLAST similarity. This is the first report on the simultaneous contamination of Cryptosporidium and Acanthamoeba in well water sources in East-Southeast Asia, the first detection of Acanthamoeba spp. in biofilms in the Philippines, and the longest viability demonstrated for A. lenticulata in two-year-old water samples stored at room temperature.

Characterization and diversity of macroin-vertebrates in groundwater in the region of Souk-Ahras (North-East of Algeria)

Abstract A preliminary inventory of macroinvertebrate communities and a regular physicochemical analysis of groundwater were carried out in the Souk Ahras region (north-eastern Algeria). It aims to study and analyze the structure and distribution of underground aquatic species, thus determining the relationship that may exist between the quality of water in wells and springs with the diversity of aquatic fauna present in the habitats. Through 2018, 14 stations (10 wells and 4 springs) were monitored on a monthly basis, while water and aquatic fauna samples were taken. A principal component analysis (PCA) of the physicochemical quality parameters was carried out from the average values of each parameter. It has been observed that the waters are highly mineralized, due to the high values of total hardness, salinity, and sulfate levels in certain stations. The sources of contamination are mainly due to the raw wastewater circulating in the small canals. Also “seguias” are used either to evacuate wastewater or for irrigation, which seeps down to the water table. The collected aquatic fauna in all the 14 stations is diversified and contains 29 families which correspond to 4 taxa.

Monitoring of heavy metals and essential trace elements in aquatic plant Ranunculus sphaerospermus Boiss. & Blanche (Ranunculaceae), sediments, and water of volcanic Haydarlar Lake, Türkiye

Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. Monitoring of trace element and heavy metal concentrations is important to understand the possible environmental risks in natural aquatic environments. In the present study, concentrations of some heavy metals and trace elements in aquatic plant Ranunculus sphaerospermus, sediments, and water samples of volcanic Haydarlar Lake were analyzed by using ICP-OES. The concentrations were found in the following ranges: 82.11 – 97.38, 9174.50 – 9942.29, and 0.63 – 0.89 for Al; 10.29 – 17.43, 30.60 – 55.60, and 0.81 – 0.98 for B; 1038.44 – 1682.30, 4017.26 – 4503.54, and 1276.61 – 1541.41 for Ca; 120.69 – 178.41, 6894.50 – 8103.47, and 0.51 – 0.69 for Fe; 2503.51 – 2983.38, 1118.50 – 1693.38, and 69.43 – 93.82 for K; 563.38 – 783.22, 885.32 – 1122.47, and 108.55 – 143.36 for Mg in the plant (mg kg−1), sediment (mg kg−1), and water (mg L−1) samples, respectively. The concentrations of Ca, Fe, and K elements in sediments and the content of Ca and K in lake water samples were found as higher than the acceptable limit, while concentrations of all elements in R. sphaerospermus were determined to be within acceptable limits. Transfer factors (TF) of the heavy metal and essential elements from sediment to the plant samples were evaluated. The trends of TF for all samples studied were in the following order; K>Mg>B>Ca>Fe>Al. Consequently, the approach used in this study could contribute to pollution monitoring in the future.

Molecular investigation of prevalence, phenotypic and genotypic diversity, antibiotic resistance, frequency of virulence genes and genome sequencing in Pseudomonas aeruginosa strains isolated from lobster

AimAquatic organisms are too susceptible to the increased growth of bacterial contamination. It seems that preventive measures should be prioritized to reduce bacterial load, and improve the health situation of marine-based product consumers. Hence, this study is aimed at molecular investigation of the prevalence of Pseudomonas aeruginosa as one of the most food-borne pathogens, antibiotic resistance, and virulence factor encoding gens in lobster samples. MethodologyAfter the collection of aquatic samples from Isfahan and Chabahar city during the summer and autumn seasons, they were cultured, and confirmed by biochemistry tests. Then, they were investigated for antibiotic resistance by the Kirby Bauer method. Then, antibiotic resistance, virulence factor encoding genes, and Multi-Drug Resistance (MDR) patterns were analyzed. Statistical analysis was done by SPSS through chi-square tests. ResultsBacterial contamination in samples taken from Isfahan city was higher than in Chabahar city despite having a cooler climate on summer days. Antibiotic resistance to piperacillin in fresh shrimp samples taken in summer In Isfahan city was contrary to its usage as a front-line antibiotic agent for Pseudomonas aeruginosa. Lowered MDR pattern in frozen samples, was related to the varied expression of antibiotic resistance, highlighting the importance of regulations for cold chain in storage, transportation, and distribution of marine samples, especially when compared to fresh shrimps. ConclusionFood-borne pathogens, antibiotic resistance, and their virulence factors are of clinical and environmental importance. Results of our study indicated a high rate of frequency for Pseudomonas aeruginosa isolated from marine samples, antibiotic resistance, antibiotic resistance encoding genes, virulence factors encoding genes, and MDR. Maintenance of the cold chain, and proper food processing, have indispensable roles in the preservation, and reduction of Pseudomonas aeruginosa frequency in aquatic organisms.

Pilot study on the effect of secondary copper smelters on polychlorinated naphthalene contamination in surrounding agricultural areas

Polychlorinated naphthalenes (PCNs) are dioxin-like persistent organic pollutants that are primarily produced unintentionally during industrial thermal processes. These compounds are harmful to the environment and human health. This study investigated the occurrences of all 75 PCN congeners in agricultural areas near secondary copper smelters in China. The PCN concentrations in aquatic foods, eggs, crops, sediments and soils within 10 km of these smelters were higher than those in samples collected 20–30 km away from such facilities. In contrast, the PCN concentrations in compound animal feed samples collected at different distances from the secondary copper smelters were comparable to one another. Similar PCN homologue patterns were found in crop, egg, feed and soil samples collected at different distances from the smelters but the homologue profiles of PCNs in aquatic food and sediment samples collected from different distances varied. Lower chlorinated naphthalenes were the predominant homologues in most samples. The contamination of farm animals and crops with PCNs might result from the emission of these compounds from such sources into the surrounding environment. However, the health risks associated with human exposure to PCNs through food consumption are low for both distances (<10 km and 20–30 km) from secondary copper smelters.

Habitat preferences of young-of-year spotted gar (Lepisosteus oculatus) in Rondeau Bay, Lake Erie

The young-of-year (YOY) habitat of many fishes listed under the Species at Risk Act (SARA) is poorly described, yet identifying critical habitat is essential to ensure species recovery. Past research on the Endangered spotted gar ( Lepisosteus oculatus Winchell, 1864) in Canada has focused on the habitat use of adults and juveniles, but little is known about the occurrence and habitat use of YOY. Dip net and aquatic habitat sampling were performed in nearshore (lakefront, agricultural drain), mid-channel (agricultural drain), and offshore sites within Rondeau Bay to determine the fine-scale habitat occupancy patterns of age-0 spotted gar. Habitat preference analysis indicated YOY spotted gar strongly preferred shallow (0.5–1.0 m), vegetated, nearshore (lakefront and agricultural drain) habitat and avoided offshore habitat. An association between submerged aquatic vegetation (SAV) and fish size was also found, as dependence on SAV diminished as total length increased. Our study represents the first capture and assessment of habitat associations of early-stage YOY spotted gar in Canada. Given our findings, management efforts should focus on protecting the vegetated nearshore habitat in Rondeau Bay and other occupied locations in Lake Erie to ensure the long-term persistence of spotted gar in Canada.

Assessing the use of environmental DNA (eDNA) as a tool in the detection of human DNA in water.

Environmental DNA (eDNA) is a highly sensitive and cost-effective tool that is increasingly being applied to studies of biodiversity and species detection. This non-invasive method relies on the collection of environmental samples that contain genetic material being shed into surrounding environment by the target organism/s. While forensic science has a long history of using molecular tools for collecting DNA from the environment, the detection of human DNA from environmental water samples has been limited. This study investigated the detection and degradation rates of human eDNA in water samples under controlled laboratory conditions. Using a human-specific qPCR assay targeting the ND1 region of human mitochondrial DNA, eDNA degradation over time in water spiked with human blood was assessed. Recovery of nuclear DNA was investigated by determining if routine DNA short tandem repeat (STR) profiles of the blood source could be generated. Results demonstrated that human eDNA remains detectable for up to 11 days under laboratory conditions in environmental water and up to 35 days in distilled water. Partial STR profiles could be recovered from environmental water only up to 24 h, while, in distilled water, partial profiles continued to be recovered up to 840 h. These findings demonstrate that sampling human eDNA from aquatic samples can provide reliable human DNA detection within relatively short time windows, assisting law enforcement agencies by providing information about the potential time an individual may have been present in an area or assisting in the detection and location of a body or remains in aquatic environments.

A Comparison of the Efficiency of Aquatic Macroinvertebrate Sampling Tools Used in Lotic Environmental Impact Assessment of Human Activities in A Tropical Mountain Stream in Eastern Uganda

The study was aimed at comparing the efficiency of three macroinvertebrate sampling tools used in lotic environmental impact assessment of River Sipi including Surber sampler, rock-filled basket and Kick net sampling tools. The efficiency of the sampling tools was based on the data collected by each sampling tool, which was in turn used to calculate the Relative variation (RV) (efficiency), diversity, richness, and relative abundance, time taken to sort macroinvertebrate per sample and taxa assemblage. Data was analysed using a two-way ANOVA that was performed under the R Development Core Team 2010. The results indicated that despite the fact that all the sampling tools were efficient in sampling macroinvertebrates with RV&lt;25%, both kick net and rock-filled basket obtained closely comparable efficiency results with Relative Variation ranging between 0.54-2% for the kick net and 1.4-3.6% for rock filled basket. Of the three sampling tools, the kick net was the most efficient, collecting a greater diversity of macroinvertebrate taxa (1.81±0.04) and a greater number of specimens (1444), abundance (66.4±0.25%), greater taxa richness (11±0.41) but required the biggest amount of time to sort macroinvertebrates (26±0.71minutes). In conclusion, the rock-filled basket served as the next best alternative efficient sampling tool to kick net in sampling macroinvertebrates.

Rapid Nucleic Acid Extraction for Aquatic Animal DNA Virus Determination Using Chelex 100 Resin via Conventional PCR and Digital Droplet PCR Detection

Simple SummaryConvenient, fast, and high-quality nucleic acid extraction methods are urgently needed in molecular diagnostic testing for viral pathogens in aquaculture. We developed a viral DNA extraction method from diseased tissues and cells using the Chelex 100 resin solution workflow. The only extraction reagents required are the Chelex 100 resin and phosphate-buffered saline. The whole extraction process only takes about 15 min from the tissue homogenate to obtain the DNA. The concentration of extracted DNA is at least 100 ng/µL. This methodology has clear benefits in terms of cost and time saving compared to the commercial kit extraction for aquatic animal DNA virus determination by PCR in the laboratory. In addition, the simplified method using Chelex 100 resin with a pH value of 10–11 presented excellent results in PCR application and could be a standard for the DNA extraction for DNA virus testing in the future.Molecular diagnostic testing for viral pathogens is crucial in aquaculture. The efficient and convenient preparation of pathogenic microbial nucleic acids is the basis of molecular diagnosis. Here, we developed a simplified deoxyribonucleic acid (DNA) extraction method from aquatic animal DNA viruses using the Chelex 100 resin. The nucleic acid was extracted from infected tissues and cell culture for the detection of three common aquatic viral pathogens (CEV, CyHV-2, and GSIV). We compared the extraction effects of a current commercial kit extraction method and the Chelex 100 resin extraction method according to nucleic acid concentration, conventional polymerase chain reaction (PCR), and digital droplet PCR (ddPCR). The results indicated that both extraction procedures could obtain high-quality nucleotide samples. Extracting DNA using the Chelex 100 resin led to better detective efficiency for ddPCR molecular diagnostic testing. The whole process took less than 20 min, and only Chelex 100 resin solution was added to the tissues or cells without multiple tubes being transferred several times. The extracted DNA concentration and the detection sensitivity were high. These results indicated that the Chelex 100 resin solution has the advantages of speed, efficiency, and economy compared to the commercial kit. In addition, the higher pH value (10–11) of the Chelex 100 resin solution markedly improved the detection sensitivity compared to a lower pH value (9–10). In conclusion, the comparison of the Chelex 100 Resin and commercial viral DNA extraction kits revealed the good performance of the Chelex 100 resin solution at pH 10–11 in DNA extraction for PCR amplification from aquatic animal viral samples of tissues and cells in molecular diagnostic testing. It is both rapid and cost-effective.

Enhanced resolution of marine viruses with violet side scatter.

Marine viruses make up an essential compartment of the marine ecosystem. They are the most abundant organisms and represent one of the biggest sources of unknown biodiversity. Viruses also have an important impact on bacterial and algal mortality in the ocean, and as such have a major influence on microbial diversity and biogeochemical cycling. However, little is known about the abundance and distribution patterns of viruses across the oceans and seas. Over the last 20 years, flow cytometry has been the technique of choice to detect and count the viral particles in natural samples. Nevertheless, due to their small size, the detection of marine viruses is still extremely challenging. In this article we describe how a new generation of flow cytometer which uses the side scatter (SSC) of violet photons from a 405 nm laser beam helps to improve the resolution for detecting marine viruses. To the best of our knowledge, this is the first report where virioplankton has been detected in aquatic samples using flow cytometry with a 405 nm violet SSC instead of a 488 nm blue SSC.

Temporal design for aquatic organismal sampling across the National Ecological Observatory Network

Abstract The National Ecological Observatory Network (NEON) is a continental‐scale research platform designed to assess the impacts of climate change, land‐use change and invasive species on ecosystem structure and function at field sites distributed across 20 ecoclimatic domains (or regions) from Alaska to Puerto Rico. Aquatic sites within the NEON network include 24 streams, 7 lakes and 3 rivers among 19 domains. A significant challenge to this effort is defining standardized methodology for sampling at sites with substantially variable geomorphology and hydrology. The aquatic temporal sampling design provides timing windows for seasonal sampling to best assess organismal diversity and abundance. The need to establish a rule set for temporal sampling was addressed via site‐specific seasonal sampling windows, defined using a suite of environmental variables collected from publicly available meteorological data. Variables integrated into the design include stream flow, growing degree days and riparian phenology. Thresholds for these variables were determined using published literature and used to create three sampling windows for each sample site. Sampling windows target biological community diversity and seasonal changes in abundance, and roughly align with spring, mid‐summer and autumn. NEON‐generated organismal data from 2014 to 2021 were analysed for inter‐ and intra‐annual variability to quantify community‐scale variability among seasonal sampling windows and years at each site. Algae, macroinvertebrate and zooplankton community structure was significantly different within sites across sampling windows, supporting the sampling design of three separate windows per year. Moreover, 93% of sampling windows were completed from 2014 to 2021. An analysis of macroinvertebrate data at 14 sites shows that seasonal β‐diversity represents an important attribute of the stream community, even if interannual trends among sites may differ. We conclude that the temporal sampling design for NEON aquatic biological sampling is justified in having three sampling windows per site and is achievable at most NEON aquatic sites. Although sampling windows have been adjusted at a select number of sites, the original sampling windows are used successfully at the majority of NEON aquatic sites. Sampling windows will be updated with NEON continuous sensor data from each site once sufficient (&gt;3 years) data are available.

Dynamic Cell Imaging: application to the diatom Phaeodactylum tricornutum under environmental stresses

ABSTRACT The dynamic movement of cell organelles is an important and poorly understood component of cellular organization and metabolism. In this work we present a non-invasive non-destructive method (Dynamic Cell Imaging, DCI) based on light scattering and interferometry to monitor dynamic events within photosynthetic cells using the diatom Phaeodactylum tricornutum as a model system. For this monitoring we acquire for a few seconds movies of the signals that are related to the motion of dynamic structures within the cell (denoted scatterers), followed by a statistical analysis of each pixel time series. Illuminating P. tricornutum with LEDs of different wavelengths associated with short pulsed or continuous-wave modes of illumination revealed that dynamic movements depend on chloroplast activity, in agreement with the reduction in the number of pixels with dynamic behaviour after addition of photosystem II inhibitors. We studied P. tricornutum under two environmentally relevant stresses, iron and phosphate deficiency. The major dynamic sites were located within lipid droplets and chloroplast envelope membranes. By comparing standard deviation and cumulative sum analyses of the time series, we showed that within the droplets two types of scatterer movement could be observed: random motion (Brownian type) but also anomalous movements corresponding to a drift which may relate to molecular fluxes within a cell. The method appears to be valuable for studying the effects of various environments on microalgae in the laboratory as well as in natural aquatic environments. HIGHLIGHTS Light scattering is an alternative to fluorescence to rapidly evidence dynamic processes. Lipid droplets are the major metabolic active sites under stress. A non-destructive visualization method suitable for laboratory microalgae and aquatic samples.

Development of a fully automated analytical platform based on static headspace-gas chromatography-tandem mass spectrometry for the analysis of five N-nitrosamines in dried aquatic products of animal origin.

The development of rapid and sensitive monitoring methods for trace N-nitrosamines (NAs) in foodstuffs is essential for mitigating the potential health risks to consumers. In the present study, an analytical platform based on one step fully automated static headspace sampling and gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed and validated for the analysis of N-nitrosamines in dried aquatic products of animal origin. The samples and sodium chloride solution mixture were incubated in a heated headspace vial for analyte evaporation, coupled to automatic sampling and online GC-MS/MS analysis. The proposed method requires minimal sample preparation and organic solvent consumption. Five N-nitrosamines including N-nitroso dimethylamine, N-nitroso methyl ethylamine, N-nitroso pyrolidine, N-nitroso piperidine and N-nitroso diphenylamine were selected as model compounds to optimize the significant factors by a using Box-Behnken design. The optimum conditions achieved limits of detections in the range 0.08-0.29 μg kg-1 , with correlation coefficient over 0.998. Relative recoveries in dried aquatic product sample were in the range 76.9-92.4%, with relative SDs of 1.9-7.2%. These results confirm the reliability of the developed method for further application in trace level monitoring of the target analytes in foodstuffs. © 2022 Society of Chemical Industry.

Invasive alien aquatic plant species management drives aquatic ecosystem community recovery: An exploration using stable isotope analysis

The socio-economic and ecological impacts of invasive alien aquatic plant (IAAP) species have been well studied globally. However less is known about ecosystem recovery following the management of IAAP species. This study employed a before-after study design to investigate ecological recovery following the management of Salvinia molesta D.S. Mitchell, at four field sites in South Africa. We hypothesized that the presence of S. molesta would have a negative impact on the ecosystem food web structure, and that following S. molesta control, the systems would show positive ecosystem recovery. Aquatic macroinvertebrate and macrophyte samples collected before and after mechanical or biological control of S. molesta, were analysed for δ13C and δ15N stable isotopes. Salvinia molesta infestations negatively impacted the food web structure, indicated by reduced food chain length, trophic diversity and basal resources. This represented an altered aquatic food web structure, that in some cases, led to the collapse of the aquatic community. In contrast, after either mechanical or biological control, there were increases in food chain length, trophic diversity and abundance of energy resources accessed by consumers, indicating improved food web structure. Although the study showed positive ecosystem recovery following control, we noted that each control method followed a different recovery trajectory. We conclude that S. molesta invasions reduce aquatic biodiversity and alter ecosystem trophic dynamics and related ecosystem processes, necessitating control.

Microplastic Production from Plastic Recycling Village in Van Lam, Hung Yen Province

This study aims to evaluate the microplastic production and its occurence in water and sediment from Minh Khai commune, Hung Yen province. Research on the scales and methods of plastic recycling was conducted in 10 different manufacturing facilities. We quantified and classified microplastics present in water, sediment, and aquatic animal samples in the canals that receive wastewater from the production facilities. The results show that the plastic recycling village currently has 48 plastic recycling facilities in operation, the average amount of recycled plastic is 2.21 ± 0.095 tons/household/day. There are 8 main disposal points that discharge wastewater . The measured discharging rate is 15.1-16.8 m3/h. The microplastic content in the environment was found to be 0.33 ± 0.05 g/L, in which microplastics had 0.03 g/L. In river water, of all the microplastic we found, 67% were plastic flakes and 33% were other plastics. In the sediment, 0.45% were microplastics and 4.63% were plastic fragments. This is the first study to detect and quantify microplastics in the environment from the plastic recycling village. It is necessary to expand research in wastewater discharging points to complete the process of quantifying and classifying microplastics.&#x0D;