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Geographic origin of sea cucumber is topic of interest for both consumers and producers since the prices of sea cucumber vary largely according to their geographic origins. It is currently important that a scientific technique should be developed for determining geographic origin as a mean to detect fraudulent labeling. We have therefore developed a technique to classify the geographic origin of sea cucumber based on elemental analysis combined with the statistical analysis. In this study, a total of 39 elements contents of sea cucumber from five major production regions in China were determined to evaluate their applicability in the origin traceability of sea cucumber. Pattern recognition techniques including principal component analysis (PCA) and linear discriminate analysis (LDA) were applied to evaluate their performance in terms of classification or predictive ability. Thirty six elements in sea cucumber samples of different regions showed significant differences ( p  < 0.05), which proved that the elemental composition was an effective tool for distinguishing different origins of sea cucumber. Classification of sea cucumber using PCA did not give satisfactory results. The LDA gave an overall correct classification rate of 94.1% and cross-validation rate of 88.2%. These results demonstrated the usefulness of multi-element fingerprints as indicators for authenticating the geographical origin of sea cucumber in China. [ABSTRACT FROM AUTHOR]

Abstract Reconstructing heavy metal historical trends are essential for better understanding anthropogenic impact on marine ecosystems. In this work, the ecological risk and sources of Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb in Jiaozhou Bay were studied and the anthropogenic metal emissions was also quantified. The ecological risk was mainly caused by Cd, As and Cu, which presented an increasing trend with increased anthropogenic activities since the 1950s. The statistical analysis show that Cr, Mn, Ni, Cu and Zn were primarily from natural sources. Cadmium and Mn might originate from both natural and anthropogenic sources. Arsenic and Pb were sourced from agricultural activities and atmospheric precipitation, respectively. The anthropogenic flux of Cr, Mn, Ni, Cu, Zn, As, Cd and Pb were 138, 586, 63, 66, 161, 35, 0.31 and 44 mg/m2/a since the 1950s. Over 40.0% of Cu and As were quantified from anthropogenic emissions since the 1950s. Highlights • Jiaozhou Bay sediments reflected regional anthropogenic metal emissions. • Anthropogenic source heavy metals present an increasing trend since 1950s. • Risk contribution ratios of Cd, As and Cu were 48.8%, 20.8% and 9.3%, respectively. • Over 40% of Cu and As were quantified from anthropogenic source since the 1950s. [ABSTRACT FROM AUTHOR]

The Weihai coast is a representative zone with fifty-year history of mariculture in China. Algae and shellfish are the main cultured species, other species including fish and sea cucumber are also cultivated. In this study, heavy metals in surface sediments, sampled along the Weihai coast during May yearly between 2009 and 2013 were investigated in terms of their contents and spatiotemporal variation. The contents of Zn, Cr, Cu, Cd, Pb and As showed different spatiotemporal variations and ranged between 11.6 and 115.9, 4.15–51.3, 5.2–21.9, 0.02–0.33, 6.0–54.2, and 2.9–18.7 μg g − 1 , respectively. Among them, Zn, Cu and As declined during the five years. Ecological risk assessment revealed that Cd posed a moderate risk, as compared to other five elements, which were relatively low risks in surface sediments. Source analysis revealed that Zn, Cr and Cd were mainly from lithogenic contribution, while As was likely from anthropogenic discharges. [ABSTRACT FROM AUTHOR]

[Display omitted] • China has made significant advances in IRMS food traceability in the last decade. • More than 100 IRMS research papers describe a wide range of foods in China. • Chinese IRMS studies use multi-isotopes combined with chemometric models. • High-accuracy isotope models trace food fraud and mislabeling. • Rapid growth of IRMS food studies in China enhances food safety and quality. Over the last decade, isotope ratio mass spectrometry (IRMS) using up to 5 light stable isotopes (13C/12C, 2H/1H, 15N/14N, 18O/16O, 34S/32S) has become more widely applied for food origin verification as well as food authentication in China. IRMS technology is increasingly used to authenticate a range of food products including organic foods, honey, beverages, tea, animal products, fruits, oils, cereals, spices and condiments that are frequently unique to a specific region of China. Compared to other food authenticity and traceability techniques, IRMS has been successfully used to characterize, classify and identify many Chinese food products, reducing fraud and food safety problems and improving consumer trust and confidence. IRMS techniques also provides scientific support to enhance China's strict government regulatory policies. Isotope testing verifies geographical origin labelling of domestic and imported foods, protects and verifies high value foods that are unique to China, and indicates environmentally friendly farming practices such as 'green' or 'organic' methods. This paper reviews recently published Chinese research to highlight the recent advances of IRMS as a regulatory and verification tool for Chinese food products. [ABSTRACT FROM AUTHOR]

Seasonal variations of heavy metals in integrated poly-cultured scallops and seawater from Ailian Bay, northern China were analyzed to reveal the potential factor in bioaccumulation of metals in scallop Chlamys farreri. Results showed that heavy metals (Cu, Zn, As, Cd, Cr, Pb and Hg) in seawater were much below the maximum permissible limits and showed no seasonal changes, but were consistent with the growing period of the poly-cultivated kelp. The content of Zn in scallop tissues was highest with an average value of 88.35 ± 11.50 mg/kg, and Hg content was lowest (0.046 ± 0.025 mg/kg). The accumulation of Cu, As, Cd and Hg in scallops presented a significant seasonal change, and they were closely correlated with the physicochemical quality instead of heavy metals in seawater. Cadmium provided 88.9 % of the total hazard index for adults and 72.2 % for children. Arsenic should also be paid more attention in the risk assessment of human health. • Seasonal variation of heavy metals in poly-cultured scallops are little known. • Heavy metals in seawater were very low without seasonal changes. • Some heavy metals in scallops showed significant seasonal changes. • Heavy metals in scallops were correlated with physicochemical factors of seawater. • Integrated multi-trophic culture can improve food safety of scallops. [ABSTRACT FROM AUTHOR]

Arsenic (As) and As speciation in marine bivalves have been widely investigated. However, little is known about the bioaccumulation and biotransformation of inorganic As in different tissues of scallops. Therefore, the tissue-specific accumulation, biotransformation and subcellular partitioning of As were investigated in Chlamys farreri following 12 d inorganic As [arsenite (AsⅢ) and arsenate (AsⅤ)] exposure and 30 d depuration. Total As levels were highest in the kidneys and lowest in the adductor muscle after 12 d exposure for both As (Ⅲ) and As (Ⅴ) treatment groups, and the bioavailability of As (Ⅲ) was significantly higher than that of As (Ⅴ) for C. farreri. After 30 d elimination, total As levels were significantly decreased to the control levels. The subcellular fate of As in five different tissues was similar for different inorganic As treatment groups. The greatest proportion of As was found in the metallothionein-like protein fraction (MTLP) and the second was the cellular debris (CD). A little part of As (Ⅲ) could be oxidized to As (Ⅴ) in the gill and digestive gland for As (Ⅲ) treatment groups, and the reduction of As (Ⅴ) to As (Ⅲ) happened in the gill and kidney under As (Ⅴ) exposure. Although a high methylation activity was found in C. farreri , it varied in different tissues with different inorganic As species exposure. The present results indicated that exposure to As (Ⅲ) and As (Ⅴ) could induce different responses in bioaccumulation and biotransformation in five tissues of C. farreri. • Biotransformation of waterborne inorganic arsenic in C. farreri was studied. • Bioaccumulation capabilities of inorganic As in C. farreri related to As species. • Detoxification strategy of As in C. farreri was studied by subcellular partition. • High methylation activity in the gill and kidney were observed in C. farreri. [ABSTRACT FROM AUTHOR]

The determination of the geographical origins of seafood is significant for food safety and health of consumers. It is necessary to develop a feasible method of identifying the geographical origins of sea cucumbers in China. In this study, 76 sea cucumbers collected from five different regions in China were analyzed for the stable isotope ratios and compositions of carbon (C), nitrogen (N), oxygen (O) and hydrogen (H). One way analysis of variance was adopted for the study of the differences in the stable isotope ratios and compositions of C, N, O and H in these sea cucumbers. The principal component analysis (PCA) and linear discriminant analysis (LDA) were used as exploratory techniques and classification procedures, respectively. The one way analysis of variance showed that there was a significant difference (p < 0.05) in the stable isotope ratios and compositions of C, N, O and H in the sea cucumbers, which proved that the stable isotope ratios and compositions of C, N, O and H were useful in the identification of the origins of sea cucumbers. Based on the PCA, there was no clear distinction between the sea cucumbers from different regions. High recognition (93.4%) and satisfactory predictive ability (89.5%) were achieved with the LDA. The present findings suggest that the analysis of the stable isotope ratios and compositions of C, N, O and H combined with the statistical analysis could be potentially applied in the discrimination of the geographical origins of sea cucumbers. • Elemental and isotope of C, N, O, and H were used to trace sea cucumber origins. • δ18O and δ2H were first used to identify the origin of sea cucumber. • Stable isotope of C, N, O, and H in sea cucumber was significantly different. • High recognition (93.4%) and predictive (89.5%) ability were achieved by LDA. [ABSTRACT FROM AUTHOR]

• A significant organ-specific total cadmium distribution in Zhikong scallops (Chlamys farreri) • The bioaccessibility of total Cd ranged from 44.0% (kidney) to 90.2% (gonad) for different tissues of C. farreri. • Steaming decreased the total Cd bioaccessibility in the mantle, gill, gonad, digestive gland and muscle. • The reactive cadmium ions (Cd2+) could be detected in the digestive juice of five tissues except for the muscle. • The bioaccessible Cd2+ content in the digestive gland, gill and gonad tissues all significantly increased after steaming. Scallop is well known for its high accumulation of cadmium. The bioaccessibility and speciation of cadmium in different tissues of scallops during gastrointestinal digestion could influence the evaluation of its biological effects and consumption safety in humans. The bioaccessibility of total Cd ranged from 44.0 % (kidney) to 90.2 % (gonad) for different tissues of scallop Chlamys farreri. Steaming decreased the total Cd bioaccessibility in the mantle, gill, gonad, digestive gland and the muscle. During in vitro digestion, the reactive inorganic Cd2+ could be detected in the digestive juice of five tissues except for the muscle. Steaming process increased the bioaccessible Cd2+ content for the digestive gland, gill and gonad tissues. Based on the bioaccessible total Cd and Cd2+ content, the muscle, gonad, and mantle of the steamed scallops are the safe tissues for human consumption according to the scenarios of Cd intake established by WHO and EFSA. [ABSTRACT FROM AUTHOR]

The geographical origin of sea cucumber Apostichopus japonicus plays a key role in affecting its economic value. To quickly and effectively identify the geographical origin of sea cucumbers, Fourier transform near infrared (FT-NIR) spectroscopy coupled with machine learning methods (random forest, gradient boosting decision tree, light gradient boosting machine) was applied and compared in present study. The results showed that a light gradient boosting machine (lightGBM) model achieved the best performance by proper sampling and preprocessing techniques. The mutli-class logloss during the model training can reach as low as 0.36. The accuracy, precision, recall, F1 score and the area under curve for the test sets prediction was 0.91, 0.92, 0.91, 0.91, 0.98, respectively. These indicators showed the lightGBM model established has good robustness and strong generalization ability. The results proved that NIR spectroscopy combined with lightGBM could be used as a rapid and effective technique for tracing the geographical origin of sea cucumbers. • 167 sea cucumber samples were evaluated by FT-NIR spectroscopy. • Ensemble learning methods were used for geographical classification of the samples. • Good accuracy was achieved by a lightGBM model with proper data pretreatment. • FT-NIR coupled with machine learning provides a promising classification tool. [ABSTRACT FROM AUTHOR]

The exponential growth of off-shore mariculture worldwide over the last 20 years has had significant impact on coastal sediment biogeochemistry. However, there are no long-term records of the cumulative impacts of mariculture on the benthic bacterial community. Here, total (DNA) and active (RNA) bacterial community compositions were characterized using MiSeq sequencing of 16S rRNA gene in four core sediments of the Ailian Bay, one of the typical intensive mariculture areas in China with more than fifty-year history of kelp and scallop cultivation. The γ-Proteobacteria, δ-Proteobacteria, Acidobacteria and Acitinobacteria were more abundant in the total bacterial communities, while β-Proteobacteria, Anaerolineae, Clostridia, Spirochaetes and Cyanobacteria were enriched in the active bacterial communities. Significant differences were observed between total and active benthic bacterial communities. The influences of different mariculture modes on the total bacterial communities were more significant than those on the active bacterial communities. Only limited groups of the total bacterial communities were significant influenced by the cumulative effects of the long-term mariculture. The bacterial genera with the function in the sulfide cycling and organic consumption were enriched in the total bacterial population of the integrated multi-trophic aquaculture (IMTA) areas. The variations of both total and active bacterial communities were significantly influenced by grain sizes, total organic carbon and nutrients. Both total and active bacterial communities exhibited a slightly stronger response to environmental factors than to spatial (distance) factors. The effects of mutualism might dominate the total and active bacterial networks in the Ailian Bay. The present study demonstrated that the cumulative influences of the long-term and intensive IMTA mariculture on total benthic bacterial communities in the sub-surface sediments of the Ailian Bay were stronger than those on the active benthic bacterial communities, which provided some insights into the potential ecological roles of specific taxa in the sediments of the IMTA ecosystems. Unlabelled Image • Significant differences between total (DNA) and active (RNA) benthic bacterial communities were observed. • Long-term mariculture showed only slightly cumulative influences on the benthic bacterial communities. • Bacterial genera in the sulfide cycling and organic consumption were enriched in the total bacteria of the IMTA areas. • Variations of both total and active bacterial community were influenced by grain sizes, total organic carbon and nutrients. • Mutualism effect dominated in the total and active bacterial networks in the Ailian Bay. [ABSTRACT FROM AUTHOR]

The seasonal dynamics and diagenesis of trace metals at two contrasting coastal sites were studied to determine the mechanism that drove the diffusive release of trace metals from sediments in the Changjiang Estuary. Porewater trace metal concentrations were 53.4–4829 nM for Zn, 11.0–344 nM for Cu, 7.75–221 nM for Cr, 2.71–61.1 nM for Co, 0.822–42.7 nM for Pb and 0.037–4.22 nM for Cd. The concentrations and profiles of trace metals in the porewater and solid phase displayed obvious regional and seasonal variations. This variation was mainly reflected in the surface layer and the depth of the suboxic and anoxic layers. Regionally, surface porewater trace metal concentrations in the seasonal hypoxic region were higher than those in the aerobic region due to changes in the redox conditions being beneficial to the release of trace metals. Seasonally, surface porewater trace metal concentrations decreased in summer compared to spring due to their removal by forming metal sulfides in summer. Solid profiles of the trace metals supported their dynamic variations in the porewater. The partition coefficient suggested that the formation of Fe/Mn (hydr)oxides was effective for the removal of trace metal in oxidizing condition, while the formation of sulfides was conducive to the removal of trace metals in reducing condition. The combination of porewater with solid phase data suggested that the dynamics of Cu, Zn, Cr and Co were mainly controlled by Fe and Mn diagenesis, the dynamics of Cd were affected by S cycling, and the dynamics of Pb were disturbed by anthropogenic inputs and benthic organism activities. Estimation of benthic fluxes indicated that sediments were an important source of trace metals in the water column. The contributions of trace metals by sediments to the water column of the Changjiang Estuary were only one order of magnitude lower than those by riverine fluxes. Unlabelled Image • Seasonal dynamics of trace metals at SWI of the Changjiang Estuary are absent. • Mechanism that drove the diffusive release of trace metals at SWI was studied. • Seasonal cycling of trace metals was more obvious in the seasonal hypoxic zone. • Solid profiles of trace metals supported their dynamic variations in porewater. • Benthic diffusion was an important contributor to trace metals in water column. [ABSTRACT FROM AUTHOR]

Atmospheric wet deposition (AWD) is an important pathway for anthropogenic and natural pollutants entering aquatic ecosystems. However, the study on the magnitudes and ecological effects of AWD of various nutrient species (nitrogen, phosphorus and silicon) on Jiaozhou Bay is scarce. To address these issues, in this study, wet deposition samples were collected at a coastline site along Jiaozhou Bay from June 2015 to May 2016. Dissolved inorganic nitrogen (DIN, including NH 4 –N, NO 3 –N and NO 2 –N), dissolved organic nitrogen (DON), dissolved inorganic phosphorus (DIP, i.e. PO 4 –P), dissolved organic phosphorus (DOP) and reactive silicate (SiO 3 –Si) were analyzed. The volume-weighted mean (VWM) concentrations of NH 4 –N, NO 3 –N and DON in AWD were higher compared with those of NO 2 –N, PO 4 –P, DOP and SiO 3 –Si. The annual influxes of NH 4 –N, NO 3 –N, NO 2 –N, DON, DIP, DOP, and SiO 3 –Si via AWD were 92.8, 54.5, 0.427, 47.5, 0.274, 0.448 and 1.73 mmol·m − 2 ·yr − 1 respectively; NH 4 –N and DOP were the dominant species for N and P, and the roles of DON and DOP in AWD could not be neglected. Significant seasonal variations were observed in concentrations and fluxes of all nutrient species owing to the effects of rainfall, the intensities of local emission sources and the long-distance transports of natural and anthropogenic pollutants. The major sources of N, Si and P in AWD were agricultural activities, soil dust and a mixing one involving both anthropogenic and natural sources, respectively. Though AWD represents relatively low percentages of external inputs for nutrients and low contribution to primary productivity (PP) of Jiaozhou Bay, large amounts of nutrient inputs originating from sudden heavy rains may enhance PP prominently, as well as aggravate P-limitation and Si-limitation and further affect phytoplankton community structures and size-fractioned structures with the quite high DIN:DIP ratios and extremely low Si:DIN ratios in AWD. [ABSTRACT FROM AUTHOR]

The geographical origin of sea cucumber Apostichopus japonicas plays an important role in determining its market value. This study investigated the feasibility of using multi-element profile combined with explainable machine learning to trace the origin of sea cucumber in China. Multi-element profile (23 elements) of 167 sea cucumber samples was determined with ICP-OES and ICP-MS, and used for construction and evaluation of 4 ensemble learning models. Extreme gradient boosting (XGBoost) model achieved superior performance with an overall accuracy, precision, recall, F1 score and AUC as 0.95, 0.93, 0.91 and 1, respectively. The Shapley Additive Explanations (SHAP) algorithm was subsequently applied to interpret the XGBoost model output for desirable geographical information. Se was identified as the most important elemental marker for discriminating sea cucumber origins. Therefore, with clarified scientific support, multi-element profile combined with machine learning model could serve as a powerful tool for identifying the provenance of sea cucumber. • Multi-element profile of 167 sea cucumber samples was analyzed by ICP-OES and ICP-MS. • XGBoost model achieved best geographical classification performance. • SHAP was applied to interpret the XGBoost model for desirable information. • Selenium was identified as the most important elemental marker for geographical origins. [ABSTRACT FROM AUTHOR]