Occurrence of microplastics in the Haima cold seep area of the South China Sea.

The pollution of deep-sea microplastics has received increasing attention. As a special ecosystem in the deep sea, the cold seep area is of great significance for studying the distribution of microplastics in the deep sea. In this work, the distribution and characteristics of microplastics in seawater, sediments, and shellfish in the Haima cold seep area and the correlation between the characteristics of microplastics in different media and the type of media were studied. Microplastics were found in all three media. The abundance of microplastics in different samples from the Haima cold seep area ranged 1.8-3.8 items/L for the seawater, 11.47-96.8 items/kg (d.w.) for the surface sediments, and 0-5 items/individual (0-0.714 items/g) for the shellfish. The amount of microplastics ingested by shellfish varied among different species. The microplastics in these three media were mainly fibrous, dark-colored, small-sized rayon, polyethylene terephthalate (PET), and polyethylene (PE). In the correlation analysis of microplastic characteristics among the three media, it was found that the characteristics of microplastics in different media in the same area were closely related, and each pair of variables showed a significant positive correlation (P ≤ 0.05). The distinctive geographical conditions would accelerate the interchange of microplastics among various media. Principal component analysis showed that habitat contribute to microplastic feature differences in shellfish. Differences in correlation were observed between the characteristics of shellfish microplastics in different regions and the characteristics of microplastics in surrounding seawater and sediments.

Confinement-enhanced microalgal individuals biosensing for digital atrazine assay.

Microalgal sensors are widely recognized for their high sensitivity, accessibility, and low cost. However, the current dilemma of motion-induced spatial phase changes and concentration-related multiple scattering interferes with induced test instability and limited sensitivity, which has hindered their practical applications. Here, a differentiated strategy, named confinement-enhanced microalgal biosensing (C-EMB), is developed and proposed to pave the way. The in-situ printed microgel trap is designed to confine Chlamydomonas reinhardtii individuals, stabilizing their spatial phase. The microgel trap arrays are introduced to eliminate the multiple scattering of microalgae, breaking the existing effective concentration in traditional microalgal sensing and enabling sensitive assays. The integration with lab-on-a-chip technology and a developed digital imaging algorithm empower portable and automated detection. With this system, a microalgae analyzer is developed for atrazine detection, featuring a linear range of 0.04-100 µg/L. We assess the system's performance through practical atrazine assays on commercial food, using a double-blind test against a standard instrument. Our results demonstrate the good accuracy and test stability of this system with the mean bias atrazine detection in corn and sugarcane juice samples (SD) were 1.661 µg/L (3.122 µg/L) and 3.144 µg/L (4.125 µg/L), respectively. This method provides a new paradigm of microalgal sensors and should advance the further applications of microalgal sensors in commercial and practical settings.

Elder fish means more microplastics? Alaska pollock microplastic story in the Bering Sea.

Marine microplastics are an increasingly big concern. We analyze the occurrence of microplastics in Alaska pollock (Gadus chalcogrammus) across 2+ to 12+ ages sampled from the Bering Sea. Results show that 85% of the fish have ingested microplastics and elder fish ingest more with over a third of microplastics in the 100- to 500-micrometer size range, indicating the prevalence of microplastics in Alaska pollock distributed in the Bering Sea. A positive linear relationship is obtained between fish age and microplastic size. Meanwhile, the number of polymer types increases in elder fish. The link between microplastic characteristics in Alaska pollock and the surrounding seawater suggests an extended spatial impact of microplastics. The impact of age-related microplastic ingestion on the population quality of Alaska pollock is still unknown. Therefore, we need to further investigate the potential impact of microplastics on marine organisms and the marine ecosystem, taking age as an important factor.

Microplastics in global bivalve mollusks: A call for protocol standardization.

A growing body of evidence shows that microplastic pollution is ubiquitous in bivalve mollusks globally and is of particular concern due to its potential impact on human health. However, non-standardized sampling, processing, and analytical techniques increased the difficulty of direct comparisons among existing studies. Based on 61 peer-reviewed papers, we summarized the current knowledge of microplastics in bivalve mollusks globally and provided an in-depth analysis of factors affecting the outcome of microplastic data, with the main focus on the effects of different species and methodologies. We found no significant differences in microplastic abundance among genera from the same family but significant differences among bivalve families, indicating habitats play an important role in microplastic ingestion by bivalve mollusks. This also provided foundational knowledge for using epifaunal and infaunal bivalves to monitor microplastic pollution in water and sediment, respectively. Recommendations for microplastic monitoring protocol in bivalve mollusks were proposed according to the results of this review, covering (i) a sample size of at least 50 bivalves in the study area, (ii) the use of 10 % KOH as the digestion solution, and (iii) the pore size of a filter membrane of < 5 µm. Acknowledging the need for a standard procedure, more efforts towards protocol standardization used in long-term and large-scale microplastic monitoring programs in bivalve mollusks are needed.

Identification of severe fever with thrombocytopenia syndrome virus genotypes in patients and ticks in Liaoning Province, China.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS), caused by the SFTS virus (SFTSV), is an acute infectious disease transmitted by ticks that has recently been identified. There are no reports of epidemic serotypes in Liaoning Province, PR China. The aim of this study was, therefore, to identify genotypes of SFTSV in this province. METHODS: In 2019, quantitative PCR testing was performed on 17 patients suspected of being infected with SFTS in Liaoning Province and on 492 ticks from the counties and cities surrounding the patients' residences. Four samples were subjected to virus isolation and whole-genome amplification. RESULTS: Molecular diagnostic results confirmed SFTSV infection in five of the 17 suspected cases of SFTS and in 12 of the 492 ticks, with a prevalence of 2.4%. Four strains of SFTSV were successfully isolated from patients' blood and ticks. Phylogenetic analysis after whole-genome amplification and sequencing showed that they all belonged to genotype A of SFTSV. CONCLUSIONS: This study is the first to determine the genotype of SFTSV in patients and ticks in Liaoning Province, PR China. The results deepen our understanding of the SFTS epidemic and provide information on the variability in mortality rate among genotypes.

Occurrence and spatial distribution of trace metals in seawaters of the Drake Passage and Antarctic Peninsula.

In this study, surface seawater was collected from 82 stations in the Drake Passage and Antarctic Peninsula sea area, and the distribution characteristics and correlations of 11 trace elements (i.e., V, Cr, Mn, Co, Cu, Zn, As, Mo, Cd, Pb, and U) in the seawater were analyzed. Results showed remarkable differences in the concentration of different elements, among which those of Mn (53.15%), Mo (22.77%), Zn (9.81%), and U (6.23%) were relatively high. The concentration of trace elements in Drake Passage water was relatively low, likely because a westerly drift that enhances large circulating currents exists in the sea area, thereby affecting the distribution of substances in the water. Mn, Co, Cu, Zn, Cd, and Pb showed relatively high concentrations at more stations than the other elements, and the high concentrations of Mn, Co, and Cd were mainly found in shallow water areas. UV, MoV, AsV, AsMo, AsU, and MoU demonstrated good linear correlations with correlation coefficients in the range of 0.878-0.961. These results could provide support for further explorations of the environmental behavior of trace elements in Antarctica.

Microfluidic-based in vitro thrombosis model for studying microplastics toxicity.

The potential impact of microplastics (MPs) on health has caused great concern, and a toxicology platform that realistically reproduces the system behaviour is urgently needed to further explore and validate MP-related health issues. Herein, we introduce an optically assisted thrombus platform to reveal the interaction of MPs with the vascular system. The risk of accumulation has also been evaluated using a mouse model, and the effect of MPs on the properties of the thrombus are validated via in vitro experiments. The microfluidic system is endothelialized, and the regional tissue injury-induced thrombosis is then realized through optical irradiation. Whole blood is perfused with MPs, and the invasion process visualized and recorded. The mouse model shows a cumulative risk in the blood with continuous exposure to MPs (P-value < 0.0001). The on-chip results show that MP invasion leads to decreased binding of fibrin to platelets (P-value < 0.0001), which is consistent with the results of the in vitro experiments, and shows a high risk of thrombus shedding in real blood flow compared with normal thrombus. This work provides a new method to further reveal MP-related health risks.

Outcomes of Ischemic Stroke and Associated Factors Among Elderly Patients With Large-Artery Atherosclerosis: A Hospital-Based Follow-Up Study in China.

Large-artery atherosclerotic (LAA) stroke is the most common subtype of ischemic stroke. However, risk factors for long-term outcomes of LAA stroke in the elderly Chinese population have not been well-described. Therefore, we aimed to assess outcomes and risk factors at 3, 12, and 36 months after LAA stroke onset among stroke patients aged 60 years and older. All consecutive LAA patients aged ≥ 60 years were prospectively recruited from Dongying People's Hospital between January 2016 and December 2018. The clinical features and outcome data at 3, 12, and 36 months after stroke were collected. Differences in outcomes and relationship between outcomes and risk factors were assessed. A total of 1,772 patients were included in our study (61.7% male, 38.3% female). The rates of mortality, recurrence, and dependency were 6.6, 12.6, and 12.6%, respectively, at 3 months after stroke onset. The corresponding rate rose rapidly at 36 months (23.2, 78.7, and 79.7%, respectively). We found the positive predictors associated outcomes at 3, 12, and 36 months after stroke onset. The relative risk (RR) with 95% confidential interval (CI) is 1.06 (1.02-1.10, P = 0.006) at 3 months, 1.06 (1.02-1.10, P = 0.003) at12 months, and 1.10 (1.05-1.15, P < 0.001) at 36 months after stroke onset for age; 1.09 (1.01-1.19, P = 0.029) at 12 months for fasting plasma glucose (FPG) level; 4.25 (2.14-8.43, P < 0.001) at 3 months, 4.95 (2.70-9.10, P < 0.001) at 12 months, and 4.82 (2.25-10.32, P < 0.001) at 36 months for moderate stroke; 7.56 (3.42-16.72, P < 0.001) at 3 months, 11.08 (5.26-23.34, P < 0.001) at 12 months, and 14.30 (4.85-42.11, P < 0.001) at 36 months for severe stroke, compared to mild stroke. Hypersensitive C-reactive protein (hs-CRP) level was an independent risk factor for mortality at different follow-up times, with the RR (95%) of 1.02 (1.01-1.02, P < 0.001) at 3 months, 1.01 (1.00-1.02, P = 0.002) at 12 months. White blood cell count (WBC) level was associated with both stroke recurrence (RR = 1.09, 95%CI: 1.01-1.18, P = 0.023) and dependency (RR = 1.10, 95%CI: 1.02-1.19, P = 0.018) at 3 months. In contrast, a higher level of low-density lipoprotein cholesterol (LDL-C) within the normal range was a protective factor for recurrence and dependency at shorter follow-up times, with the RR (95%) of 0.67 (0.51-0.89, P = 0.005) and 0.67 (0.50-0.88, P = 0.005), respectively. These findings suggest that it is necessary to control the risk factors of LAA to reduce the burden of LAA stroke. Especially, this study provides a new challenge to explore the possibility of lowering LDL-C level for improved stroke prognosis.

A nanofluidic device for ultrasensitive and label-free detection of tetracycline in association with γ-cyclodextrin and GO.

Herein, an ultrasensitive and selective nanofluidic device for tetracycline (TC) was developed in association with γ-cyclodextrin and graphene oxide (GO). The assay was designed based on the change of the nanochannel surface charge due to the selective recognition ability of GO between aptamers and TC-aptamer complexes. And γ-cyclodextrin was utilized to eliminate the excess TC since the amine group molecules were inclined to be adsorbed onto the nanochannel surface and affected the adsorption efficiency of the nanochannel. In the presence of TC, TC specifically binded to the aptamer to form TC-aptamer and was separated from GO. The TC-aptamer complexes could be quantitated with conical nanochannels coated with polyethyleneimine (PEI)/Zr4+. The redundant TC was removed by γ-cyclodextrin. The detection limit of the nanofluidic device was as low as 2 ng L-1 (S/N = 3) and the linear range was 10 ng L-1 to 10 µg L-1. Moreover, the nanofluidic device provided high specificity and good recovery rates of 94.8-109.3% in natural river, tapwater and wastewater samples. The results revealed that our study provided a new rapid detection method for trace contaminant analysis.

Rapid nitrate determination with a portable lab-on-chip device based on double microstructured assisted reactors.

Determining the nitrate levels is critical for water quality monitoring, and traditional methods are limited by high toxicity and low detection efficiency. Here, rapid nitrate determination was realized using a portable device based on innovative three-dimensional double microstructured assisted reactors (DMARs). On-chip nitrate reduction and chromogenic reaction were conducted in the DMARs, and the reaction products then flowed into a PMMA optical detection chip for absorbance measurement. A significant enhancement of reaction rate and efficiency was observed in the DMARs due to their sizeable surface-area-to-volume ratios and hydrodynamics in the microchannels. The highest reduction ratio of 94.8% was realized by optimizing experimental parameters, which is greatly improved compared to conventional zinc-cadmium based approaches. Besides, modular optical detection improves the reliability of the portable device, and a smartphone was used to achieve a portable and convenient nitrate analysis. Different water samples were successfully analysed using the portable device based on DMARs. The results demonstrated that the device features fast detection (115 s per sample), low reagent consumptions (26.8 µL per sample), particularly low consumptions of toxic reagents (0.38 µL per sample), good reproducibility and low relative standard deviations (RSDs, 0.5-1.38%). Predictably, the portable lab-on-chip device based on microstructured assisted reactors will find more applications in the field of water quality monitoring in the near future.

Comparative study of three sampling methods for microplastics analysis in seawater.

Microplastics, as an emerging pollutant, are widely spread in the oceans. The sampling method is the most basic and important factor affecting the reported microplastic abundance data. Three sampling methods, most commonly used for microplastic collection, including direct filtration with 0.45 µm pore size membrane, 20 µm sieve pre-concentration followed by 0.45 µm filtration and Manta trawling with a 150 µm mesh size net were studied. The results showed that there were orders of magnitude difference in abundance of microplastic across the three methods with 0.45 µm direct filtration yielding 1600.0-4000.0 items/m3, 20 µm sieve pre-concentration yielding 10.0-50.0 items/m3, and 150 µm trawl net yielding 0.13-0.24 items/m3. The polymer types of microplastic collected by the three methods were similar, but polymer proportions were different. PES and rayon dominated in the samples collected by direct filtration and sieve pre-concentration. PES and PP accounted for a higher proportion in the trawling samples. The abundance and polymer types of microplastics had a clear correlation between direct filtration and sieve pre-concentration (p < 0.05). More microplastic shapes were found in trawling samples. The average and median sizes of microplastics increased with increasing pore or mesh size. According to the size fraction and standard deviation of microplastic size in different samples of each method, the stability of method decreased with increasing pore or mesh size. The trawling method had a higher sampling efficiency, but its stability was weaker than the other two methods. Our results suggested that an appropriate method should be selected upon actual sampling condition and available tools during the research process to improve the credibility of the results.

New insights into the toxic interactions of polyvinyl chloride microplastics with bovine serum albumin.

The binding interaction between emerging pollutant polyvinyl chloride microplastics (PVC MPs) and bovine serum albumin (BSA) was studied by fluorescence spectroscopy, resonance scattering spectroscopy (RLS), UV-visible (UV-vis) absorption spectroscopy, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. Fluorescence results revealed that the fluorescence quenching of BSA induced by PVC MPs was originated from the formation of BSA-PVC complex in static quenching mode. According to Stern-Volmer equation, the binding constants (Ka) between PVC MPs and BSA at different temperatures were obtained, and the number of binding sites was 1.62. The thermodynamic parameters, enthalpy change (ΔH), entropy change (ΔS), and free energy change (ΔG) were calculated to be - 41.77 kJ mol-1, 43.17 J mol-1 K-1, and - 54.63 kJ mol-1 via Van't Hoff equation, indicating electrostatic interaction played a key role in the formation of BSA-PVC complex spontaneously. In addition, the alterations of microenvironment and secondary structure in BSA induced by PVC MPs were further confirmed by synchronous fluorescence spectra, UV-vis, FT-IR, and CD. This work not only provides further information for better understanding the binding interaction of PVC MPs with BSA, but also elucidates the potential biological toxicity of MPs at a molecular level.

An examination of the occurrence and potential risks of microplastics across various shellfish.

The ingestion of microplastics by shellfish pose a potential health risk for human via seafood consumption. This study investigated and compared the contamination levels and potential human health risks of microplastics in the digestive system of commercial shellfish from North (Qingdao) and South (Xiamen) China. Microplastics were detected in 70%-100% of shellfish samples from Qingdao and 70%-90% of shellfish samples from Xiamen, with abundances ranging from 1.2 to 4.1 items/individual (or 0.8-4.4 items/g, wet weight of digestive system) in shellfish from Qingdao and 1.3-6.0 items/individual (or 2.1-4.0 items/g) in shellfish from Xiamen. The microplastic composition was dominated by rayon and tended to be fibrous in shape, and white, black, and transparent in color. Microplastics <500 µm were the dominant size range, in which the size range of 100-200 µm was the most abundant size. Features of microplastics in the water-dwelling shellfish were different from those of the sediment-dwelling shellfish, and the microplastic features in the shellfish correlated with the sampling region, shellfish length, total wet body weight, and wet weight of the digestive system. Risk assessment results revealed that the potential human health risk posed by microplastics from the digestive system of commercial shellfish was higher in Qingdao than Xiamen.

Colorimetric determination of Hg2+ based on the mercury-stimulated oxidase mimetic activity of Ag3PO4 microcubes.

Four kinds of Ag3PO4 materials were prepared by controlling the experimental conditions, which were developed as oxidase mimics. Experimental results showed that different synthesis methods led to distinct crystal structures, morphologies, and surface properties, which contributed to diverse oxidase-like activities of Ag3PO4 materials. Among them, Ag3PO4 microcubes (APMCs) can efficiently catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine in the presence of dissolved oxygen to form a blue-colored oxide, presenting the best intrinsic oxidase mimetic ability. The higher-energy [110] facets with more oxygen vacancies exposed and more active sites coupled with more negative charge and larger specific surface area of APMCs contributed to its enhanced oxidase mimetic performance. Besides, mercury ions were proved to remarkably and selectively stimulate the oxidase-like ability of APMCs owing to the formation of Ag-Hg amalgam on its surface. Based on the stimulating effect of Hg2+ towards APMCs, a simple and rapid method for colorimetric determination of Hg2+ was thus established via the significant signal amplification and megascopic color variation. Under the optimal conditions, the sensing system showed a good linear relationship ranging from 0.1 to 7.0 µM and a detection limit of 20 nM for Hg2+, exhibiting high selectivity and good colour stability. Moreover, the colorimetric method was successfully applied to determine Hg2+ in real water samples. Considering these advantages, the developed colorimetric sensing system is expected to hold bright prospects for trace determination of Hg2+ in biological, environmental, and food samples. Graphical abstract The preparation process of Ag3PO4 materials and Hg2+-stimulated enhanced oxidase-like ability of Ag3PO4 microcubes in catalyzing the oxidation of TMB to generate a typical blue color, which can be applied in rapid and ultrasensitive detection of Hg2+ visually.

CoMoO4 nanobelts as efficient peroxidase mimics for the colorimetric determination of H2O2.

CoMoO4 materials were prepared through a simple hydrothermal method and developed as highly efficient peroxidase mimics for colorimetric determination of H2O2. Based on the different experimental conditions in the synthesis process, the CoMoO4 materials present distinct morphologies, structures, surface properties, and peroxidase mimetic activities. Among them, CoMoO4 nanobelts (NBs) display the best intrinsic peroxidase mimetic abilities due to the high-energy (100) facet exposed, more Co active sites at (100) facet, more negative potential, and larger specific surface area. It can efficiently catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to generate a blue oxide. In view of the excellent peroxidase mimetic catalytic activity of CoMoO4 NBs, a rapid, convenient, and ultrasensitive method was successfully established for the visual and colorimetric determination of H2O2. The method exhibits good selectivity, practicability, stability, and reusability, and has a detection limit of 0.27 µM. The peroxidase mimetic catalytic mechanism of CoMoO4 NBs was illustrated according to the kinetic and active species trapping experiments. The method has a good potential for rapid and sensitive determination of H2O2 for biomedical analysis. Graphical abstract Schematic presentation of the process of CoMoO4 nanobelts catalyzing the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to generate a typical blue color, which can be applied in rapid and ultrasensitive detection of H2O2 visually.

Vertical distribution of microplastics in bay sediment reflecting effects of sedimentation dynamics and anthropogenic activities.

Microplastics are ubiquitous in our environment, yet we have little knowledge on their accumulation profile and changing trend. In this study, we selected the semi-enclosed Jiaozhou Bay as the research area to study the vertical distribution characteristics of microplastic in the sediment and analyzed factors that might affect this distribution pattern. We found six different polymer types and the microplastic abundance ranged between 2.5 items/kg d.w.-27.5 items/kg d.w.. Microplastic abundance was very low in deep sediment and generally showed a decreasing trend from the surface down with some shifts at different depth at certain sites. Based on our data, the total microplastics in the sediment were estimated to reach 3.71 tons in Jiaozhou Bay. This study shows that the vertical microplastic abundance profile in the sediment can not only show the microplastics pollution level but also reflect environmental factors and anthropogenic impacts.

Colorimetric detection of H2O2 based on the enhanced peroxidase mimetic activity of nanoparticles decorated Ce2(WO4)3 nanosheets.

In this paper, nanoparticles decorated Ce2(WO4)3 nanosheets (CWNSs) with negative potential and large specific surface area were synthesized and developed as highly efficient peroxidase mimics for colorimetric detection of H2O2. CWNSs can efficiently catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to induce an obvious color variation. Kinetic analysis indicated that the catalytic behaviors of CWNSs obey the typical Michaelis-Menten mechanism. The peroxidase-like catalytic mechanism of CWNSs was proposed according to the active species trapping experiments, verifying that ·O2- radicals played primary roles in the catalytic reaction. Based on the strong and stable peroxidase-like catalytic activity of CWNSs, a simple, rapid, selective, and ultrasensitive method was successfully established for colorimetric detection of H2O2. The method has a good linear response ranging from 0.5 µM to 100 µM for H2O2 concentration with a lower detection limit of 0.15 µM. Benefitting from the sensitive response and good stability, the method is applied in real sample detection and shows a favorable reproducibility and feasibility. This work not only provides a novel enzymatic mimics with remarkable catalytic activities for biomedical and environmental analysis, but also extends the application area of Ce2(WO4)3 materials.

Probing the toxic interactions between polyvinyl chloride microplastics and Human Serum Albumin by multispectroscopic techniques.

In this study, the interaction of emerging pollutant polyvinyl chloride microplastics (PVC MPs) and human serum albumin (HSA) was investigated by fluorescence spectroscopy, UV-visible (UV-vis) absorption spectroscopy, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy under simulated physiological conditions. Fluorescence results showed that PVC MPs (about 5000 nm in size) can effectively quench the intrinsic fluorescence of HSA through static quenching owing to the formation of HSA-PVC complex. The binding constants (Ka) between PVC and HSA at different temperatures were calculated as 4.97 × 103 M-1, 3.46 × 103 M-1 and 2.51 × 103 M-1, respectively. The number of binding sites was 1.26. The enthalpy change (ΔH), entropy change (ΔS) and free energy change (ΔG) were calculated to be -59.27 kJ·mol-1, 70.76 J·mol-1 K-1 and - 80.35 kJ·mol-1, respectively, indicating that the interaction of PVC with HSA was mainly driven by electrostatic forces. Moreover, results of UV-vis, FT-IR and CD further demonstrated that the microenvironment and secondary structure of HSA were changed a lot induced by PVC, leading to a decrease in α-helix. This work not only provides an insight into the intermolecular interaction between PVC and HSA, but also elucidates the potential biological toxicity of MPs at a molecular level.

A Portable and Accurate Phosphate Sensor Using a Gradient Fabry-Pérot Array.

Here, a portable and accurate phosphate sensor using a gradient Fabry-Pérot array (FPA) is proposed. It can form a bidirectional gradient concentration (absorbance) distribution in the gradient FPA, simplifying the complex operations to get a standard curve and saving time. The gradient FPA can effectively filter out the interference (bubbles, light intensity, and salinity) while improving the absorbance, achieving a highly accurate and stable detection. Besides, the smartphone simplifies data processing and makes sensors more portable. In this work, the detection errors of standard solutions (100, 50, and 30 µM) are 0.39, 1.48, and 1.84%, respectively, and it has also been demonstrated with errors of 2.46 (sample 1, seawater), 2.08 (sample 2, lake water), and 1.83% (sample 3, sewage) for natural samples detection, which is more accurate than a traditional analyzer. The sensor has a good performance when affected by bubbles, light intensity, and salinity. In addition, the detection time is shortened to 80 s, which is more time saving compared with traditional devices, and the limit of detection (LOD) is 0.4 µM. It can be predicted that the novel optofluidic sensor is conducive to build a smart nutrient monitoring system and will be applied in the field of biochemistry and environmental chemistry.

Current distribution characteristics of trace elements in the coral-reef systems of Xisha Islands, China.

The distribution characteristics, correlation, and bioavailability of 14 trace elements in different fishes and corals collected from the coral-reef systems of the Xisha Islands, China were systematic studied for the first time. All detected elements were measured using inductively coupled plasma mass spectrometry after pretreatment by microwave digestion. The fishes had slight differences in element enrichment selectivity and bioavailability with average levels as follows: V, 0.100 mg·kg-1; Cr, 0.683 mg·kg-1; Mn, 1.178 mg·kg-1; Fe, 51.806 mg·kg-1; Co, 0.072 mg·kg-1; Ni, 1.286 mg·kg-1; Cu, 1.428 mg·kg-1; Zn, 10.384 mg·kg-1; As, 6.437 mg·kg-1; Se, 0.830 mg·kg-1; Mo, 0.101 mg·kg-1; Cd, 0.051 mg·kg-1; Pb, 0.308 mg·kg-1; and U, 0.008 mg·kg-1. Trace element contents in corals were higher than those in fishes. The distribution characteristics of trace elements in fishes and corals presented a significant correlation in North Reef and Yongle Atoll, thereby indicating an evident effect on living areas compared with trace elements in fishes from the Spratly Islands. Cluster analysis of fishes and corals based on trace elements showed that they had different selectivities and bioavailabilities to trace elements. The EDI and THQ ratios of Cu, As, Cd, Cr, and Pb demonstrated that fishes were unlikely to experience serious adverse effects, except for As in Chaetodon auriga, Myripristis kuntee, Gnathodentex aureolineatus, and Hemigymnus melapterus in Xisha Islands.