Explainable machine learning for predicting the geographical origin of Chinese Oysters via mineral elements analysis.

The traceability of geographic origin is essential for guaranteeing the quality, safety, and protection of oyster brands. However, the current outcomes of traceability lack credibility as they do not adequately explain the model's predictions. Consequently, we conducted a study to evaluate the efficacy of utilizing explainable machine learning combined with mineral elements analysis. The study findings revealed that 18 elements have the ability to determine regional orientation. Simultaneously, individuals should pay closer attention to the potential risks associated with oyster consumption due to the regional differences in essential and toxic elements they contain. Light gradient boosting machine (LightGBM) model exhibited indistinguishable performance, achieving flawless accuracy, precision, recall, F1 score and AUC, with values of 96.77%, 96.43%, 98.53%, 97.32% and 0.998, respectively. The SHapley Additive exPlanations (SHAP) method was used to evaluate the output of the LightGBM model, revealing differences in feature interactions among oysters from different provinces. Specifically, the features Na, Zn, V, Mg, and K were found to have a significant impact on the predictive process of the model. Consistent with existing research, the use of explainable machine learning techniques can provide insights into the complex connections between important product attributes and relevant geographical information.

Seasonal variations of heavy metals in seawater and integrated poly-cultured scallop Chlamys farreri in Ailian Bay, northern China.

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.

Bioaccessibility and transformation of cadmium in different tissues of Zhikong scallops (Chlamys farreri) during in vitro gastrointestinal digestion.

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.

Recent advances in Chinese food authentication and origin verification using isotope ratio mass spectrometry.

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.

Solid Sampling Pyrolysis Adsorption-Desorption Thermal Conductivity Method for Rapid and Simultaneous Detection of N and S in Seafood.

In this work, a rapid method for the simultaneous determination of N and S in seafood was established based on a solid sampling absorption-desorption system coupled with a thermal conductivity detector. This setup mainly includes a solid sampling system, a gas line unit for controlling high-purity oxygen and helium, a combustion and reduction furnace, a purification column system for moisture, halogen, SO2, and CO2, and a thermal conductivity detector. After two stages of purging with 20 s of He sweeping (250 mL/min), N2 residue in the sample-containing chamber can be reduced to <0.01% to improve the device's analytical sensitivity and precision. Herein, 100 s of heating at 900 °C was chosen as the optimized decomposition condition. After the generated SO2, H2O, and CO2 were absorbed by the adsorption column in turn, the purification process executed the vaporization of the N-containing analyte, and then N2 was detected by the thermal conductivity cell for the quantification of N. Subsequently, the adsorbed SO2 was released after heating the SO2 adsorption column and then transported to the thermal conductivity cell for the detection and quantification of S. After the instrumental optimization, the linear range was 2.0−100 mg and the correlation coefficient (R) was more than 0.999. The limit of detection (LOD) for N was 0.66 µg and the R was less than 4.0%, while the recovery rate ranged from 95.33 to 102.8%. At the same time, the LOD for S was 2.29 µg and the R was less than 6.0%, while the recovery rate ranged from 92.26 to 105.5%. The method was validated using certified reference materials (CRMs) and the measured N and S concentrations agreed with the certified values. The method indicated good accuracy and precision for the simultaneous detection of N and S in seafood samples. The total time of analysis was less than 6 min without the sample preparation process, fulfilling the fast detection of N and S in seafood. The establishment of this method filled the blank space in the area of the simultaneous and rapid determination of N and S in aquatic product solids. Thus, it provided technical support effectively to the requirements of risk assessment and detection in cases where supervision inspection was time-dependent.

Bioaccumulation and biotransformation of inorganic arsenic in zhikong scallop (Chlamys farreri) after waterborne exposure.

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.

Hyperaccumulation of cadmium by scallop Chlamys farreri revealed by comparative transcriptome analysis.

Cadmium (Cd) is a hazardous environmental contaminant, which has a serious effect on the ecosystem, food safety and human health. Scallop could accumulate high concentration of Cd from the environment and has been regarded as a Cd hyper-accumulator. In this work, we investigated the antioxidative defense, detoxification and transport of Cd in the kidneys of scallops by transcriptome analysis. A total of 598 differentially expressed genes including 387 up-regulated and 211 down-regulated ones were obtained during Cd exposure, and 46 up-regulated and 260 down-regulated ones were obtained during depuration. Cadmium exposure could cause oxidative stress in the kidneys, which was particularly shown in the pathways involved in proteasome and oxidative phosphorylation. The mRNA expression of 5 metallothionein (MT) genes were overexpressed under Cd exposure and significantly decreased during Cd depuration, which played a vital role in Cd chelation and detoxification. The expression of divalent metal transporter (DMT) genes were down-regulated insignificantly during accumulation and depuration of Cd, which suggested that the DMT played little roles in Cd transport in scallops. A positive relationship in the expression of the zinc transporter (ZIP6 and ZIP1) genes with Cd exposure and depuration was observed, which confirmed its important role for Cd uptake in the kidneys of scallops. 26S proteasome activities and MT expression were Cd-dependent. This study supplied the important reference on the hyperaccumulation of Cd by scallops and identified some effective bioindicators for the environmental risk assessment.

Study of Cd Content Distribution and Its Bioaccessibility in Edible Tissues of Crab Portunus trituberculatus from the Coastal Area of Shandong, China.

Bioaccessibility study is of great significance to the health risk assessment of trace elements in the seafood. In this work, the most consumed crab (Portunus trituberculatus) in coastal area of Shandong, China was analyzed to study the distribution and the bioaccessibility of cadmium (Cd) in the edible tissues of crab, and the dietary risk from consumption of crab was also evaluated. Results showed that the content of Cd in the whole edible tissues of 109 crab specimens ranged from 0.052 to 8.89 mg/kg ww (wet weight) with mean of 2.26 mg/kg ww. The Cd content in 85% of the crab samples was higher than the national food safety limits (0.5 mg/kg ww) of China. The gender study indicated that there was no significant difference in Cd content in total edible tissues between the males and females (p > 0.05). Cadmium was highly concentrated in the brown meat with mean value of 4.13 mg/kg ww, which was about 5 times higher than that in the white meat (0.75 mg/kg ww). The bioaccessibility of Cd ranged from 48.1 to 71.0% in the white and brown meat. The risk assessment based on the bioaccessibility of Cd revealed that the consumption of the edible crab brown and white meat for adults should be limited in 0.13 kg and 1.56 kg per week respectively.

Cumulative impact of long-term intensive mariculture on total and active bacterial communities in the core sediments of the Ailian Bay, North China.

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 ß-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.

Dynamics and diagenesis of trace metals in sediments of the Changjiang Estuary.

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.

Historical trends of anthropogenic metals in sediments of Jiaozhou Bay over the last century.

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.

Speciation of heavy metals in different grain sizes of Jiaozhou Bay sediments: Bioavailability, ecological risk assessment and source analysis on a centennial timescale.

Heavy metal contamination is an essential indicator of environmental health. In this work, one sediment core was used for the analysis of the speciation of heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) in Jiaozhou Bay sediments with different grain sizes. The bioavailability, sources and ecological risk of heavy metals were also assessed on a centennial timescale. Heavy metals were enriched in grain sizes of < 63µm and were predominantly present in residual phases. Moreover, the mobility sequence based on the sum of the first three phases (for grain sizes of < 63µm) was Mn > Pb > Cd > Zn > Cu >Ni > Cr > As. Enrichment factors (EF) indicated that heavy metals in Jiaozhou Bay presented from no enrichment to minor enrichment. The potential ecological risk index (RI) indicated that Jiaozhou Bay had been suffering from a low ecological risk and presented an increasing trend since 1940s owing to the increase of anthropogenic activities. The source analysis indicated that natural sources were primary sources of heavy metals in Jiaozhou Bay and anthropogenic sources of heavy metals presented an increasing trend since 1940s. The principal component analysis (PCA) indicated that Cr, Mn, Ni, Cu and Pb were primarily derived from natural sources and that Zn and Cd were influenced by shipbuilding industry. Mn, Cu, Zn and Pb may originate from both natural and anthropogenic sources. As may be influenced by agricultural activities. Moreover, heavy metals in sediments of Jiaozhou Bay were clearly influenced by atmospheric deposition and river input.

Heavy metals in surface sediments along the Weihai coast, China: Distribution, sources and contamination assessment.

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 2.9-18.7µgg-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.

Fluxes, seasonal patterns and sources of various nutrient species (nitrogen, phosphorus and silicon) in atmospheric wet deposition and their ecological effects on Jiaozhou Bay, North China.

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 NH4-N, NO3-N and NO2-N), dissolved organic nitrogen (DON), dissolved inorganic phosphorus (DIP, i.e. PO4-P), dissolved organic phosphorus (DOP) and reactive silicate (SiO3-Si) were analyzed. The volume-weighted mean (VWM) concentrations of NH4-N, NO3-N and DON in AWD were higher compared with those of NO2-N, PO4-P, DOP and SiO3-Si. The annual influxes of NH4-N, NO3-N, NO2-N, DON, DIP, DOP, and SiO3-Si via AWD were 92.8, 54.5, 0.427, 47.5, 0.274, 0.448 and 1.73mmol·m-2·yr-1 respectively; NH4-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.