Mariculture activities including enclosure, raft and cage cultures employ a variety of plastic gear such as fishing nets, buoyant material and net cages. The plastic gear poses a potential source of ...microplastics to the coastal environment, but relevant data on the impacts of mariculture are still limited. To this end, a semi-enclosed narrow bay (i.e., Xiangshan Bay, China) with a long-term mariculture history was investigated to assess how mariculture activities affect microplastics in seawater and sediment. The results indicated that mariculture-derived microplastics accounted for approximately 55.7% and 36.8% of the microplastics in seawater and sediment, respectively. The average microplastic abundances of seawater and sediment were 8.9 ± 4.7 (mean ± SD, n = 18) items/m3 seawater and 1739 ± 2153 (n = 18) items/kg sediment, respectively. The types of mariculture-derived microplastics included polyethylene (PE) foam, PE nets, PE film, polypropylene (PP) rope, polystyrene (PS) foam and rubber. PE foam had the highest proportion (38.6%) in the seawater samples. High usage rates and the porous structure of PE foam led to the high abundance. The average microplastic sizes of seawater and sediment are 1.54 ± 1.53 mm and 1.33 ± 1.69 mm, respectively. The spatial variations in the abundance and size of microplastics implied that the mariculture-derived microplastics in Xiangshan Bay were transported along the Bay to the open sea. The results of this study indicate that mariculture activity can be a significant source of microplastics. Further research is required to investigate how the high microplastic abundance in mariculture zone affects marine organisms, especially cultured seafood.
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•The surface seawater of Xiangshan Bay had 8.9 ± 4.7 (n = 18) microplastics per m3 seawater.•The sediments of Xiangshan Bay had 1739 ± 2153 (n = 18) microplastics per kg sediment.•Approximately 55.7% and 36.8% of the seawater and sediment microplastics were from mariculture, respectively.•The porous structure of PE foam led to high fragmentation.•Mariculture-derived microplastics in Xiangshan Bay were transported to the open sea.
Results of this work imply that the long-term intensive mariculture activities have caused a significant microplastic issue for Xiangshan Bay, China.
The automated warehouses currently in widespread use maintain highly efficient operations at the cost of consuming a large amount of energy. This study first considers the problem of operation ...optimization in multi-shuttle automated storage and retrieval systems (AS/RSs) to reduce both time and energy consumption. A time and energy bi-objective integer programming model is proposed to jointly optimize the storage/retrieval (S/R) location assignment and S/R scheduling for a multi-shuttle AS/RS. The adaptive variable neighbourhood search algorithm and Lagrangian relaxation algorithm are developed to tackle large-size instances. The results demonstrate that the bi-objective model is effective at finding the compromise solution considering travel time and energy consumption simultaneously. The decrease in travel time is obtained at the expense of increasing energy consumption and vice versa. The study provides valuable insights for warehouse managers to operate a time-efficient and energy-efficient automated warehouse.
Microplastic (MP) has been identified as an emerging vector that transports hydrophobic organic compounds (HOCs) across aquatic environments due to its hydrophobic surfaces and small size. However, ...it is also recognized that environmental factors affect MP’s chemical vector effects and that attached biofilms could play a major role, although the specific mechanisms remain unclear. To explore this issue, an in situ experiment was conducted at Xiangshan Bay of southeastern China, and dynamics of HOCs (i.e., polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)) and bacterial communities related to the model MP (i.e., PE fibers) were analyzed and compared. Through bacterial characterizations including the 16S rRNA approach, higher summer temperatures (31.4 ± 1.07 °C) were found to promote colonizing bacterial assemblages with larger biomasses, higher activity and more degrading bacteria than winter temperatures (13.3 ± 2.49 °C). Consequently, some sorbed pollutants underwent significant decline in the summer, and this decline was particularly the case for PAHs with low (2–3 rings) and median (4 rings) molecular weights such as phenanthrene (59.4 ± 1.6%), chrysene (70.6 ± 4.2%), fluoranthene (77.1 ± 13.3%) and benzaanthracene (71.5 ± 11.0%). In our winter test, however, most pollutants underwent a consistent increase throughout the 8-week exposure period. Moreover, more biorefractory pollutants including PCBs and high molecular weight (5–6 rings) PAHs accumulated regardless of bacterial characteristics. Two putative PAH-degrading bacteria appeared with high relative abundances during the summer test, i.e., family Rhodobacteraceae (18.6 ± 0.5%) and genus Sphingomicrobium (22.4 ± 3.6%), associated with drastic decreases in low (45.2 ± 0.4%) and median (66.0 ± 2.5%) molecular weight PAHs, respectively. Bacterial degradation effects of biofilms on PAHs are also supported by the correlative dynamics of salicylic acid, an important degradation intermediate of PAHs. The results of this study indicate that MP’s HOC vector effects are essentially determined by interactions between attached pollutants and microbial assemblages, which are further related to bacterial activity and pollutant features. Further studies of biofilm effects on MP toxicity and on the metabolic pathways of MP-attached HOCs are required.
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•Sorbed hydrophobic organic compounds can be degraded by attached bacteria.•Putative PAH-degrading bacteria appear with high relative abundances.•Temperature is a key factor in affecting biofilm’s biodegrading performance.•Biorefractory pollutants accumulate regardless of bacterial characteristics.
A challenge for current surface water restoration and management in China is acquiring the source information for complex pollution scenarios in order to develop effective control strategies. As an ...important part of dissolved organic matter, chromophoric dissolved organic matter (CDOM) contains unique chemical signals related to various pollution sources. Spectral methods such as fluorescence excitation-emission matrices coupled with parallel factor analysis enable rapid and low-cost CDOM characterization for source tracking. In this study, a typical small-sized river flowing through mixed land-use regions in southeastern China, the Lujiang River, was investigated to determine the responses of CDOM to spatiotemporal factors. The effects of land-use patterns were reflected by the fluorescent components of terrestrial and sewage substances. A high and stable proportion of terrestrial-like components (C1 + C2) in each sampling period (i.e., March: 47.6 ± 5.7% and October: 44.3 ± 2.7%) indicated a high input of non-point source (NPS) pollution from both agriculture and urban areas. In addition, the difference in solar radiation intensity induced by climate and air quality changes was also reflected by variability in the photodegradation product component (C3) of terrestrial precursors between October (24.8 ± 2.6%) and March (4.5 ± 2.0%), suggesting that terrestrial components could be a sensitive indicator for NPS pollutant monitoring. Increased sewage impact in downstream regions was reflected by a spike in the tryptophan-like component (C4); temporal variations in C4 (paired t-Test, p < 0.005) also indicated that sewage substances were more prone to removal by microbial activity in warmer seasons. The dynamics of C4 could serve as a good indicator of sewage disposal performance. The results of this study demonstrate that CDOM data have important practical applications for existing water restoration campaigns in southeastern China, as well as substantial potential for routine water quality monitoring.
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•The impacts of mixed land use were reflected by CDOM variations.•Non-point source impacts were reflected by terrestrial fluorescent components.•A tryptophan-like component indicated the effects of sewage discharge.•Sewage substances were prone to accumulation during the cold season.•CDOM characterization methods have applications for surface water restoration.
Here, we studied the shipyard impacts on the distribution of PAHs and PCBs in the semi-enclosed Xiangshan Bay, an important mariculture zone in China. The results showed that the shipyard caused a ...pollution plume for PAHs but not for PCBs. As characteristic pollutants of oil leakage, the PAHs had concentrations of up to 55.82 ng L−1 in the water, 2235.04 ng g−1 in suspended particulate matter (SPM), and 1489.60 ng g−1 in sediment. The PAHs in water and SPM were dominated by phenanthrene and pyrene that were mostly derived from lubricant and diesel, while those in sediments were dominated by the high-molecular-weight PAHs, such as indeno1,2,3-c,dpyrene. In contrast, the PCBs concentrations reached up to 10.17 ng L−1, 79.72 ng g−1, and 124.33 ng g−1 in the seawater, SPM, and sediment samples, respectively, and they did not show spatial patterns affected by the shipyard. Moreover, the health risk assessment indicated that the shipyard discharge caused a substantial PAHs ecological risk to the adjacent and downstream water environment. Therefore, point source discharge in semi-enclosed bays should be paid close attention to due to the strong pollutant transport effect.
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•A shipyard emission caused a significant point-source pollution effect in Xiangshan Bay, China.•Around the shipyard a visible oil film was samples containing PAHs.•Phenanthrene and pyrene were the main compounds related to lubricant and diesel.•4.The PCBs did not have an obvious distribution trend in the bay.•The shipyard emissions caused a substantial PAH ecological risk.
•Hydration of OPC is accelerated by S-water, due to the chloride promoting the precipitation.•Hydration rate of C3S is greatly affected by the concentration of chloride in solution.•Compressive ...strength of OPC mortar increased rapidly by the rapid hydration in S-water.•Chloride in S-water promoted the hydration reaction and affects hydrate assemblage.•In later age, mass of C-S-H in OPC paste with S-water is 10% lower than that with D-water.
Using seawater for concrete manufacturing promisingly provides significant economical and environmental benefits. In this study, ordinary Portland cement (OPC) hydration in distilled water and seawater and the corresponding evolution of solid phases was investigated by heat evolution, hydrated phase, hydration kinetics, and microstructure characterization. The results show that seawater can promote the early hydration of tricalcium silicate (C3S) during the hydration acceleration period. The hydrated phase assemblage was affected by the dissolved ions in seawater. Friedel’s salt was detected as a specific hydration phase in seawater, which was formed by chemical combination between the aluminate ferrite monosulfate (AFm) phase and chloride ions. The monocarboaluminate can be converted into a stable phase as Friedel’s salt in the seawater, due to the reaction with chloride ions. Furthermore, the ettringite becomes more stable when coexists with Friedel’s salt than that with monocarboaluminate, and thus ettringite formed in seawater remains 67% higher than that formed in distilled water at the later curing age. Moreover, additional unhydrated cement and less amorphous calcium silicate hydrate (C-S-H) were formed in seawater, which might be responsible for the slightly lower compressive strength of cement mortar prepared by seawater and sea sand. A modeled evolution of the solid phase and pore solution have been established, which agrees well with the characteristics of the dissolution of mineral phase, precipitation of hydration products and changes of pore solution. The related results can provide an insight into the applications of seawater and sea sand concrete for marine infrastructures.
Blind face restoration (BFR) from severely degraded face images in the wild is a very challenging problem. Due to the high illness of the problem and the complex unknown degradation, directly ...training a deep neural network (DNN) usually cannot lead to acceptable results. Existing generative adversarial network (GAN) based methods can produce better results but tend to generate over-smoothed restorations. In this work, we propose a new method by first learning a GAN for high-quality face image generation and embedding it into a U-shaped DNN as a prior decoder, then fine-tuning the GAN prior embedded DNN with a set of synthesized low-quality face images. The GAN blocks are designed to ensure that the latent code and noise input to the GAN can be respectively generated from the deep and shallow features of the DNN, controlling the global face structure, local face details and background of the reconstructed image. The proposed GAN prior embedded network (GPEN) is easy-to-implement, and it can generate visually photo-realistic results. Our experiments demonstrated that the proposed GPEN achieves significantly superior results to state-of-the-art BFR methods both quantitatively and qualitatively, especially for the restoration of severely degraded face images in the wild. The source code and models can be found at https://github.com/yangxy/GPEN.
Hypertensive disorders in pregnancy (HDPs) are leading perinatal diseases. Using a national cohort of 2,043,182 pregnant women in China, we evaluated the association between ambient temperatures and ...HDP subgroups, including preeclampsia or eclampsia, gestational hypertension, and superimposed preeclampsia. Under extreme temperatures, very cold exposure during preconception (12 weeks) increases odds of preeclampsia or eclampsia and gestational hypertension. Compared to preconception, in the first half of pregnancy, the impact of temperature on preeclampsia or eclampsia and gestational hypertension is opposite. Cold exposure decreases the odds, whereas hot exposure increases the odds. Under average temperatures, a temperature increase during preconception decreases the risk of preeclampsia or eclampsia and gestational hypertension. However, in the first half of pregnancy, temperature is positively associated with a higher risk. No significant association is observed between temperature and superimposed preeclampsia. Here we report a close relationship exists between ambient temperature and preeclampsia or eclampsia and gestational hypertension.
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