Microplastics in different tissues of historical and live samples of endangered mega-fish (Acipenser sinensis) and their potential relevance to exposure pathways.

The Chinese sturgeon (Acipenser sinensis) is an endangered freshwater mega-fish (IUCN-red listed) that survives in the Yangtze River Basin, but the population of which has declined significantly in response to environmental pressures generated by human activities. In order to evaluate the interaction between Chinese sturgeon and microplastics (MPs) for the first time, we examined the gut and gills of historical samples (n = 27), in conjunction with the blood and mucus of live samples (n = 10), to explore the potential pathways involved in MP uptake. We detected MPs in 62.9 % of the field fish, with no significant difference between guts (mean=0.9 items/individual) and gills (mean=0.8 items/individual). The abundance of MPs in fish from 2017 was significantly higher than that from 2015 to 2016 with regards to both gills and gut samples. The size of MPs in gills was significantly smaller than those in guts, yet both contained mostly fibers (90.2 %). No MPs were confirmed in blood, however 62.5 % of mucus samples contained MPs. The MPs in mucus indicated the possibility of MPs entering Chinese sturgeons if their skins were damaged. The body size of Chinese sturgeons affected their MPs uptake by ingestion and inhalation, as less MPs were detected in the gut and gills of smaller individuals. Combining the evidence from historical and live samples, we revealed the presence of MPs in different tissues of Chinese sturgeon and their potential relevance to exposure pathways. Our work expands the understanding of multiple exposure pathways between MPs and long-lived mega-fish, while emphasizing the potential risks of long-term exposure in the field.

Submerged plant-biochar composite system exhibits effective control over residual organic pollutants in the benthic organisms of aquaculture ponds.

As of now, submerged plants and biochar have demonstrated significant benefits in aquaculture pond sediment remediation. However, there is limited research on the synergistic effects of biochar and submerged plants in mitigating hydrophobic organic contaminant (HOC) accumulation in aquaculture benthic organisms and in controlling the nutrient (nitrogen and phosphorus) levels in aquaculture water. This study assesses a submerged plant-biochar system's efficacy in removing HOCs from simulated freshwater aquaculture ponds. Vallisneria natans was planted in sediment with varying levels of wheat straw biochar, while Corbicula fluminea served as the targeted benthic organism. The bioaccumulation experiment identified the optimal biochar ratio for the Vallisneria natans-biochar system in controlling HOCs in aquaculture products. Analyses included final accumulation concentrations in benthic organisms, changes in freely-dissolved concentrations in aquaculture sediment, and a mass balance calculation to explore key factors in their removal from the system. Results indicated that the Vallisneria natans-1.5% biochar composite system achieved optimal control of HOCs in sediment and aquaculture products. Biochar addition to the sediment in the composite system demonstrated a "promotion with low addition, inhibition with high addition" effect on Vallisneria natans growth. Notably, the addition of 1.5% biochar (VN1.5 group) significantly promoted the growth of Vallisneria natans leaves and roots. Comparing the final pollutant proportions in different environmental media, concentrations in water (0.20%-1.8%), clam accumulation (0.032%-0.11%), and plant absorption (0.10%-0.44%) constituted a minimal portion of the overall pollutant load in the system. The majority of pollutants (24%-65%) were degraded in the aquaculture environment, with microbial degradation likely playing a predominant role. Bacterial phyla, particularly Proteobacteria and Firmicutes, were identified as potential direct contributors to pollutant degradation in the Vallisneria natans-biochar system.

Characteristics and driving factors of antibiotic resistance genes in aquaculture products from freshwater ponds in China Yangtze River Delta.

Antibiotic resistance genes (ARGs) are widespread in aquaculture and pose a huge threat to aquaculture organisms and human health. In this study, occurrences and relative abundances of ARGs were analysed in the guts of products cultured in freshwater ponds in the Yangtze River Delta region in China. A total of 29 ARGs were found in the gut samples, with detection frequencies ranging from 4.8% to 81%, and the relative abundances (ARGs/16S rRNA) ranging from 10-7 to 1. In addition, the human dietary intake of ARGs via aquaculture products was assessed, where the daily intake of most ARGs via aquaculture products was higher than those via PM2.5 and drinking water, but lower than that via vegetables. The relative abundances of MGE (IS613, Tp614, tnpA and int1) were significantly correlated with those of multiple ARGs, indicating the horizontal gene transfer (HGT) of ARGs among gut microorganisms. Proteobacteria, Firmicutes and Actinobacteria were the dominated microbial communities found in the guts of aquaculture products. In addition, significant correlations were found between Cyanobacteria and int1, between Nitrospira and tetE, and between sul2 and aadA2, indicating potential same hosts of these genes. In addition, results from co-correlation indicated both HGT (dominated by MGEs) of ARGs and the enrichment of ARGs in bacteria. MGEs, mostly int1, were more effective than bacteria in increasing the ARG abundance. This study could provide a better understanding of the transmission of ARGs in the aquaculture environment and improve the quality of aquaculture products and the ecology.

Assessing pathways of heavy metal accumulation in aquaculture shrimp and their introductions into the pond environment based on a dynamic model and mass balance principle.

The impact of heavy metals (HMs) on the quality of aquaculture products has attracted worldwide attention. Since Litopenaeus vannamei is a popular aquaculture product among consumers worldwide, it is of great importance to guarantee its dietary safety. An in-situ monitoring program lasting for three months in a typical Litopenaeus vannamei farm found that Pb (100 %) and Cr (86 %) in the adult shrimp were higher than the safety guidelines. In the meantime, Cu (100 %), Cd (100 %) in the water and Cr (40 %) in the feed exceeded the corresponding thresholds. Therefore, quantification of different exposure pathways of shrimp and contamination origins in pond is valuable to improve the dietary safety of the shrimp. Based on Optimal Modeling for Ecotoxicological Applications (OMEGA), Cu was primarily from the ingestion of feed, accounting for 67 % of bioaccumulation, while Cd, Pb and Cr primarily entered shrimp through the adsorption from overlying water (53 % for Cd and 78 % for Pb) and porewater (66 % for Cr), respectively. The HMs in the pond water were further tracked based on a mass balance analysis. The main source of Cu in the aquaculture environment was feed, being responsible for 37 % of the total input. Pb, Cd and Cr were primarily from the inlet water with contributions of 84 %, 54 % and 52 %, respectively. In summary, the proportions of different exposure pathways and origins of HMs in pond-cultured shrimp and its living environment varied widely. To keep end-consumers eating healthily, species specific treatment is required. Feed should be regulated more for Cu. Aimed pretreatments for Pb and Cd in influent water are needed and an additional immobilization for Cr in sediment porewater should be investigated. After implementation of these treatments, the food quality improvement could be further quantified based on our prediction model.

Accumulation and re-distribution of microplastics via aquatic plants and macroalgae - A review of field studies.

The aquatic plants and macroalgae are primary producers with major roles regarding the maintenance of ecosystems but their interaction with microplastics (MPs) has received less attention than animals. We summarize the methodologies used, the MPs abundances and their characteristics across the literature on MPs pollution in aquatic plants and macroalgae. The sampling and quantification of MPs still lacks consistency between studies, which increased the uncertainty in cross-comparisons. The abundance of MPs varied by orders of magnitude between species and were mostly fibers and polymers with large degrees of production and applications. Filamentous species contained more MPs than others. The average ratio of MPs between vegetated and unvegetated sites reached 3:1. The average ratio of MPs between the biotic and abiotic fractions reached 2193:1, suggesting a high level of retention in fields. Our findings supported that aquatic plants and macroalgae are critical in the plastic flux within the marine environments.

An application of waste algae biochar in aquaculture water to remove co-existed cadmium and PAHs and the corresponding mechanism.

Water quality in aquaculture farms is highly related to the quality of aquaculture products and the connected environment. Cadmium (Cd2+) and polycyclic aromatic hydrocarbons (PAHs) are two of the most common pollutants in the aquaculture water, while biochar derived from waste algae (Enteromorpha prolifera), namely BE, was applied in farms ponds to improve water quality. Firstly, the adverse environmental impact of BE was minor, while the concentrations of the heavy metal (Cd2+ in the present study) and PAHs (FLU, PHE, FLT and PYR) were removed with efficiencies of 49%, 88%, 90%, 91% and 88%, respectively. The ecological risk values (RQs) were reduced subsequently with a rate of 58 ± 11%. After dosing BE, the ecological risk values in all the studied ponds were lower than 1, indicating no ecological risk in the corresponding aquaculture environment. The sorption capacities (qm) of BE were 15, 12, 6.3, 0.41, 0.29 and 0.56 mg·g-1 for Cd2+, FLU, PHE, FLT, PYR and BaP, respectively. The sorption capacities were acceptable compared with those derived from other types of biomass. The removal mechanisms were partition (PAHs), complexation (Cd2+), π-π interaction (Cd2+ and PAHs), precipitation (Cd2+) and ion-exchange (Cd2+). Practically and theoretically, the algae biochar is applicable in the aquaculture environment, where Cd2+ and PAHs co-exist.

Significance of the great protection of the Yangtze River: Riverine input contributes primarily to the presence of PAHs and HMs in its estuary and the adjacent sea.

The Yangtze River protection strategies are expected to improve the water quality and ecological function of the Yangtze River Estuary (YRE). The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) and 6 heavy metals (HMs) in the YRE were measured and the riverine fluxes were calculated subsequently. In particular, the concentrations of low molecular weight PAHs (LMW-PAHs), arsenic (As) and mercury (Hg) in seawater decreased over time, while those of other studied pollutants did not change a lot. In sediments, the concentration changes for all the pollutants were insignificant. For the present pollutants, the river input is the dominant source, and the flux decreased after the protection. The contribution of the discharge from wastewater treatment plants (WWTPs) was quantified. Its influence cannot be ignored. The seafood quality remained stable and the risk via diet was insignificant. Long-term monitoring is necessary, and the positive impact of the Protection Strategy is gradually emerging.

In-situ biochar amendment mitigates dietary risks of heavy metals and PAHs in aquaculture products.

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are two common contaminant groups of concern in aquaculture products. While biochar amendment can be one of the solutions to immobilize these contaminant in pond sediment, its in situ effectiveness in mitigating the bioavailability, tissue residue, and dietary risk of these contaminants is yet to be tested. In this study, we added wheat straw biochar in sediments of three aquaculture ponds with polyculture of fish and shrimps and employed passive sampling techniques (i.e., diffusive gradient in thin film for HMs and polydimethylsiloxane for PAHs) to assess the diffusion flux and bioavailability throughout the culturing cycle. Reduction in HM concentrations in organisms by biochar after 28 weeks ranged from 17% to 65% for benthic organisms and from 6.0% to 47% for fish. ΣTHQs values of HMs dropped from 2.5 to 2.1 and 1.2 to 0.91 for the two organisms with the initial ΣTHQs value above 1.0. The decrease rates of both the concentrations and ΣTHQs values followed the order of Cu > Cr > Pb > Cd, which was closely correlated with the speciation of HMs in the sediments. ΣPAHs values dropped significantly at the growth stage (20th week) and the mature stage (28th week), and, on average, by 34% across all the organisms. Carcinogenic PAHs in aquaculture products decreased dramatically at the seedling stage (12th week), while there was no significant change observed for the Incremental Lifetime Cancer Risk values. By comparing the freely-dissolved concentrations in pore water of sediments and the overlying water, consistently enhanced diffusion fluxes of HMs and PAHs from water to sediment over the whole culturing cycle were obtained. Our results demonstrated the in situ applicability of biochar amendment to remediating chemical pollution in aquaculture environment and safeguarding quality of aquatic products.

In situ application of the diffusive gradients in thin film technique in aquaculture ponds for monitoring antibiotics, hormones, and herbicides.

In recent years, as the abuse of antibiotics, hormones, and herbicides has worsened in aquaculture industry, it is important to monitor the concentrations of those trace contaminants in aquaculture water more effortlessly. The aim of this study was to develop a reliable sampling method for chemical monitoring in aquaculture ponds based on the technique of diffusive gradients in thin films (DGT). A binding material (XDA-1 resin) with high adsorption capacity for antibiotics, hormones, and herbicides was selected. In laboratory, the diffusion coefficients of 11 antibiotics, 3 hormones, and 3 herbicides of the XDA-1-DGT devices were tested and ranged from 1.0×10-6 to 8.7×10-5 cm2/s. During the in situ application of XDA-1-DGT devices in different aquaculture ponds, concentrations of 11 antibiotics, 3 hormones, and 3 herbicides in aquaculture water (CSOLN) via grab sampling were also analyzed and found ranging from 0.03 to 6.3 ng/L, lower than the results based on DGT (CDGT) (1.2-1.3×102 ng/L). The values of CDGT/CSOLN were larger than one unit, suggesting that the rates of resupply of target chemicals (antibiotics, hormones, and herbicides) by the desorption and diffusion of pond water were higher than the rates of uptake by XDA-1-DGT, and pond water was proved a sufficient reservoir of antibiotics for DGT application. The value of Log (CDGT/CSOLN) of 1.1 derived from the application in the aquaculture ponds of 14 regions in Eastern China can be a reference value for future chemical monitoring based on DGT technique. And the accuracy of this value was found hardly affected by the physical and chemical properties of chemicals with pKa ranging from -1 to 12, Log Kow ranging from 0 to 4.5, and Log solubility ranging from 0.0 to 4.0.

Microplastic pollution in wild populations of decapod crustaceans: A review.

Along with the increasing amount of plastic production and waste disposal, the presence of microplastics has been confirmed in all compartments of ecosystems. The microplastics in biota is of particular concern due to the potential eco-risks associated with long term exposure and the potential for transportation along food webs. Decapoda represents a diverse taxonomic group within the subphylum Crustacea, and some of which are highly valued in fishery and biological production. The interaction between microplastic pollution and wild populations of decapod crustaceans have been documented less than fish or bivalves but are critical to understand the fates of microplastics in marine eco-systems and enrich the baselines for consumption analyses. Our review systematically summarizes the occurrence, abundance and characteristics of microplastics detected in edible and non-edible sections of decapod crustaceans from field observations. Sub-groups between crabs and shrimps were also included for comparison. The occurrence of microplastics in the edible sections were less than those in non-edible sections, and there are differences between crabs and shrimps. Fibrous microplastics and items with a size category less than 1 mm were dominant pollutants across all available literature. The methodology selection, biological features and uptake pathways play roles in the microplastic body burden in Decapoda. Our work enriches the understanding of microplastic pollution in wild populations of decapod crustaceans but their contribution to the human exposure to microplastics needs to be addressed with more accurate measurements.

Applicability of Equilibrium Sampling in Informing Tissue Residues and Dietary Risks of Legacy and Current-Use Organic Chemicals in Aquaculture.

Equilibrium sampling based on silicone polydimethylsiloxane (PDMS) has been used to determine the concentrations of freely dissolved hydrophobic organic compounds (HOCs) and assess the thermodynamic potentials for bioaccumulation of these compounds in the aquatic environment. This allows the use of PDMS-based sampling techniques in assisting conventional sampling and extraction methods for the determination of the concentrations of HOCs in aquaculture products. The present study is an ex situ demonstration of how well PDMS can inform the tissue residues and dietary risks of legacy or current-use organic chemicals in aquaculture species from farm ponds in eastern China. For legacy contaminants such as polybrominated diphenyl ethers (PBDEs, n = 10), good agreement between the predicted concentrations based on PDMS and the measured lipid-normalized concentrations was observed for 60% of the studied biota, including both pelagic and benthic species. For pesticides currently used, such as pyrethroid (PE) (n = 4) and organophosphate pesticides (OPPs, n = 7), the measured tissue residues were consistently higher than those predicted by PDMS, possibly caused by the continuous input from the surroundings. For the organochlorine pesticides (OCPs, n = 5), the only detected chemical was also underestimated. Adjusted by ingestion rates of aquaculture products and toxicology data, the target hazard quotients of these chemicals predicted from PDMS were generally comparable to those derived from measured concentrations in tissue because of the predominance of PBDEs. Overall, PDMS-based equilibrium sampling offered an alternative approach for the prediction of tissue residues and dietary risks of PBDEs. Moreover, it should be applied with caution for PEs, OPPs, and OCPs. Improving the application of PDMS for these chemicals in farm ponds warrants future study. Environ Toxicol Chem 2021;40:79-87. © 2020 SETAC.

Antibiotics in cultured freshwater products in Eastern China: Occurrence, human health risks, sources, and bioaccumulation potential.

The adverse effects of antibiotics residues on aquaculture ecosystems and humans raised increasing concerns globally. To assess the occurrence, human health risks, sources, and bioaccumulation potential of antibiotics in cultured freshwater products in Eastern China, 12 and 13 aquaculture ponds were selected in 2018 and 2019, respectively, both covering 8 aquatic species. Concentrations of 12 commonly-used antibiotics were measured in muscle tissue of aquaculture products, water, sediment, and suspended particles. At least two antibiotics were found simultaneously in all muscle tissue samples. The concentrations of most antibiotics in freshwater cultured products were at a medium or lower level in comparison with other studies in China and worldwide, but slightly higher than the concentrations in cultured marine products. The potential risks from the intake of these aquatic products were also evaluated. The results showed limited adverse effects due to the consumption of these products with an exception of fluoroquinolone antibiotics. The bioaccumulation potential from water varied widely in different collection years, but the bioaccumulation factor (BAF) values for antibiotics were all <50 L/kg. BSAF values of antibiotics were all far below 1, except for one site in Zhejiang province in 2018, indicating that the bioavailability from surface sediments was low, in a particular pond environment. The low repeatability of BAF and BSAF calculated in two years indicated a relatively unsteady status in terms of bioaccumulation potential of cultured freshwater ponds yearly.

Contribution of aquatic products consumption to total human exposure to PAHs in Eastern China: The source matters.

Demand for aquatic products surges, due to the increasing concerns on high-quality nutrition and food security. Eastern China is the leading area in contributing significantly to both production and consumption of aquatic products from inland aquaculture, coastal fishing, and distant-water fishing. It is imperative to comprehensively assess the dietary risks of common chemical hazards, such as polycyclic aromatic hydrocarbons (PAHs) in aquatic products of these supply origins, and the contribution of aquatic product consumption to total human exposure. The observed body loads of total PAHs in the coastal aquatic products varied significantly, indicating an unstable food quality from the east coast of China. In the meantime, benzo[a]pyrene equivalent concentrations (BaPeq) exhibited the highest level in the aquatic products from inland farm ponds. High BaPeq, along with high consumption of inland aquaculture products, led to higher corresponding cumulative carcinogenic risks (ILCRs) than the other two kinds of products, which further indicate that the origins and consumption rates of the aquatic products do matter. Furthermore, it is confirmed that the consumption of aquatic products is an important contributor to the total daily exposure to PAHs, especially for children and pregnant women. Finally, it is necessary to apply practical remediation in aquaculture farm ponds to provide high-quality products, especially for the population groups of children and pregnant women, and alleviate the exposure and risk due to the PAHs in aquatic products.

Magnetic activated carbon (MAC) mitigates contaminant bioavailability in farm pond sediment and dietary risks in aquaculture products.

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are among the contaminants of concern in aquaculture ponds due to their frequent detection and high bioaccumulation in aquatic products and hence high dietary risks to human beings. In this study, magnetic activated carbon (MAC) was added as a stabilization and removal adsorbent to native pond sediment with known contamination of HMs and PAHs to reduce the tissue residues and dietary risks of HMs and PAHs in a model aquaculture species (Venerupis philippinarum) in the course of a 28-day bioaccumulation experiment. Meanwhile, passive sampling techniques based on diffusive gradient in thin films (DGT) and polydimethylsiloxane (PDMS) were applied to sense the bioavailable fraction of HMs and PAHs in sediment during the stabilization process. The results showed that 3% dosage of MAC to sediment achieved the most cost-effective stabilization for HMs and PAHs. A remarkable decrease was observed with the tissue residues of HMs and PAHs in V. philippinarum (28-47% for HMs and ~76% for ∑PAHs), which was quantitatively linked to the decline in their bioavailable concentrations in sediment pore water (31-46% for HMs and ~76% for ∑PAHs). Consequently, the target hazard quotients (THQs) posed by HMs and incremental lifetime cancer risks (ILCRs) by PAHs in V. philippinarum were reduced by 38% and 46%, respectively. Along with the magnetic recovery of ~70% MAC from the sediment, HMs (4.8-13%) and PAHs (2-60%) can be effectively removed. We further established a multi-domain equilibrium sorption model that was able to predict the optimal amendment of MAC for quantitative mitigation of bioavailable PAHs in sediment pore water within a certain range of MAC dosage. Future studies are warranted to explore the applicability domain of MAC for in situ remediation in aquaculture ponds to ensure the quality of farming organisms or to serve other purposes in aquatic systems.

Reduced bioavailability and ecological risks of polycyclic aromatic hydrocarbons in Yangshan port of East China Sea: Remediation effectiveness in the transition from construction to operation.

To assess the remediation effectiveness of ecological restoration in the transition period from construction to operation of Yangshan Port, the largest deepwater port of East China Sea, we employed equilibrium passive sampling and partitioning theory to assess the changing bioavailability and flux of polycyclic aromatic hydrocarbons (PAHs) in relation to bioaccumulation and ecological risks in marine organisms. Due to the ecological restoration efforts, both the bulk and bioavailable concentrations of PAHs in sediment and surface seawater samples decreased dramatically after the port entered the operation phase, as compared with those reported during the last construction phase. PAH concentrations in the marine organisms also showed a dramatic decline, and corresponded to the change in the freely dissolved fractions of PAHs in sediment/surface water according to their thermodynamic potential for bioaccumulation. While trophic magnification of ΣPAHs was observed in the pelagic communities, concentrations of PAHs in benthic species were relatively consistent across multiple trophic levels, and were generally higher than those in pelagic species. The differing bioaccumulation between benthic and pelagic species may be related to the habitat-specific bioavailability of PAHs and the prey-predator relations among different species. The incremental lifetime cancer risks (ILCR) of PAHs in marine organisms also dropped by nearly three orders of magnitude, and were lower than the guideline (1 × 10-6) proposed by the U.S. EPA, except for several species at higher trophic levels. Overall, our study highlights an integrated use of passive sampling and equilibrium partitioning theory as a robust tool that can be applied to assess the effectiveness of ecological remediation in the port environment with quantitative, mechanistic insights from bioavailability to bioaccumulation.

Heavy metals and PAHs in an open fishing area of the East China Sea: Multimedia distribution, source diagnosis, and dietary risk assessment.

This study involved a comprehensive investigation of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in seawater, sediments, and seafoods in an important open fishing area connecting China and Japan. Cu, Pb, Cd, Cr, As, and PAHs were detected in all the studied environmental media. Specifically, Pb and low molecular weight PAHs (LMW-PAHs) were observed at high levels, due to intensive ship activities and accidental crude oil spills. Additionally, source diagnosis of PAHs suggested a potential impact from combustion. Bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAF) suggested moderate or low bioaccumulation potentials of the analytes from water and sediments, respectively. Noncarcinogenic risk assessment, based on target hazard quotients (THQs), indicated a potential low risk by consuming the studied seafoods, while the incremental lifetime carcinogenic risk assessment (ILCRs) suggested "acceptable risk" or "potential risk." However, it should be noted that there have been possibilities that the carcinogenic risk could be elevated due to bioaccumulation of the PAHs in the seafoods after long-term exposure. In summary, it is necessary to evaluate the seafood security carefully in this open fishing area due to the potential health risks.

Aquaculture Contributes a Higher Proportion to Children's Daily Intake of Polycyclic Aromatic Hydrocarbons Than to That of Adults in Eastern China.

Asia, especially China, shares a large proportion of global aquaculture production. Consequently, aquaculture food quality and safety with regard to contamination with polycyclic aromatic hydrocarbons (PAHs) were assessed in eastern China, which is a typical area of aquaculture. The concentrations of ∑PAHs ranged from 42 to 600 ng/g dry weight in a variety of dietary species from farm ponds in eastern China. With regard to the total daily intake of PAHs estimated based on the literature data on urinary hydroxy-PAHs in this region, there was a significant difference between children (mean = 130 ng/kg/d) and adults (mean = 600 ng/kg/d for pregnant women, 1700 ng/kg/d for women, and 2300 ng/kg/d for men). Furthermore, we provided a novel estimation on the fractional contribution of aquatic products to the overall human daily intake of PAHs. Specifically, the contribution of aquatic foodstuffs to total daily intake for children and pregnant women reached more than 50 and 10%, respectively, indicating that children and pregnant women were more vulnerable to the PAH-contaminated aquaculture foodstuffs. Meanwhile, no significant region-specific pattern between different provinces was observed. In summary, these results suggested that sensitive subpopulations were vulnerable to exposure to PAH-contaminated aquatic products, and it is necessary to pay attention to the dietary intake pattern of these sensitive subgroups in eastern China. Environ Toxicol Chem 2019;00:1-9. © 2019 SETAC.

[Effect of Zirconium-modified Zeolite Addition on Phosphorus Release and Immobilization in Heavily Polluted River Sediment].

The effect of zirconium-modified zeolite (ZrMZ) addition on the release and immobilization of phosphorus in heavily polluted river sediment was investigated using microcosm incubation experiments. Results showed that addition of ZrMZ to sediment greatly reduced concentrations of P in pore water and overlying water, also reducing the release flux of P across the interface between overlying water and sediment. The addition of ZrMZ to sediment resulted in the transformation of NH4Cl extractable P (NH4Cl-P), Na2S2O4/NaHCO3 extractable P (BD-P), and HCl extractable P (HCl-P) into NaOH extractable P (NaOH-rP) and residual P (Res-P) in sediment, thereby leading to the reduction of mobile P (sum of NH4Cl-P and BD-P) in sediment. Content of bioavailable P (BAP) including water soluble P (WSP), readily desorbable P (RDP), iron oxide paper strip extractable P (FeO-P), and anion resin extractable P (Resin-P) in sediment also declined following addition of ZrMZ. Control of P release from sediment by ZrMZ could be due to reduction of P in pore water and immobilization of P in sediment. Results of this work indicate that ZrMZ is very promising for controlling P release from sediments in heavily polluted rivers.

Safety and quality of the green tide algal species Ulva prolifera for option of human consumption: A nutrition and contamination study.

This study sampled U. prolifera and surface seawater from the same locations where green tide broke out in the southern Yellow Sea, in both the year 2016 and 2017. The revealed nutritive components of U. prolifera samples characterized U. prolifera as a high-protein, high-Fe, high ratio of unsaturated lipid acids and low-fat seaweed food, with an ideal ratio of essential and nonessential amino acids. The concentrations and health risk assessment of major micropollutants (heavy metals, pesticides and polycyclic aromatic hydrocarbon (PAHs)) in U. prolifera were also analyzed, respectively. The results showed that the Target Hazard Quotient values of five heavy metals (<1.0 × 10-1) and the total hazard index of 13 pesticides (<1.5 × 10-8) were lower than the unity, respectively, and the incremental lifetime cancer risk values of PAHs (<7.4 × 10-7) were lower than the USEPA limit (1.0 × 10-6). It suggested that consuming U. prolifera is safe as a food-source option, with PAHs causing relatively higher risks. PAHs from the sites closer to the shore were also found more originated from pyrolysis. We further confirmed the PAH congeners were partly in equilibrium between seawater and U. prolifera. It suggested the possibility that the food safety-risk turned to be above the USEPA limit was not high regardless of the sample collecting time. However, the sources of PAHs and their contributions to the accumulation in U. prolifera need further investigation. This study favored that U. prolifera of the green tide from the southern Yellow Sea has a potential for a nutritious-food production.

Equilibrium sampling informs tissue residue and sediment remediation for pyrethroid insecticides in mariculture: A laboratory demonstration.

Mariculture product safety in relation to sediment quality has attracted increasing attention because of the accumulation of potentially hazardous chemicals, including pyrethroid insecticides, in sediment. Passive sampling has been widely used to assess the bioavailability of sediment-associated hydrophobic organic contaminants and predict their body residue in benthic organisms. Therefore, in this study, we introduced polydimethylsiloxane (PDMS) polymer as a biomimetic "chemometer" for freely-dissolved concentrations (Cfree) to assess the efficacy of different carbon sorbents in reducing the bioavailability of pyrethroids in the process of sediment remediation. Black carbon (BC)-based materials (e.g., charcoal, biochar, and activated carbon) showed the advantageous sorption capacity over humic substance-based peat soil based on both Cfree and tissue residue in exposed clams. Of the tested BC-type materials, biochar appeared to be an ideal one in the remediation of pyrethroid-contaminated sediment. The predictive value of the PDMS chemometer approach to informing tissue residue was confirmed by a good agreement between the measured lipid-normalized concentrations of pyrethroids in clams and the lipid-based equilibrium concentrations calculated from Cfree via lipid-water partition coefficients. The quantitative inter-compartmental relationship underlying the laboratory system of sediment-pore water-PDMS-biota was also cross-validated by a mechanistically-based bioaccumulation model, thus confirming the validity of Cfree as a predictive intermediate to alert for tissue residue and guide sediment remediation. The present study revealed a great promise of sensing Cfree by polymer-based equilibrium sampling in predicting tissue residue of chemicals applied in mariculture against regulatory guidelines, and, in turn, informing remediation measures when needs arise. In situ demonstration is warranted in the future to ascertain the field applicability of this approach in real mariculture systems.