Hexabromocyclododecane-induced reproductive toxicity in Brachionus plicatilis: Impacts and assessment.

Hexabromocyclododecane (HBCD), third-generation brominated flame retardants (BRFs), has aroused worldwide concern because of its wide application and potentially negative impacts on marine ecosystems, but an information gap still exists regarding marine low-trophic organisms. Brachionus plicatilis, the model marine zooplankton, was used in the present study, and its reproductive responses were used as the endpoint to indicate HBCD-induced toxicity. HBCD was suggested to be extremely highly toxic compounds regarding the 96 h-LC50 of 0.58 mg L-1. The sublethal exposure of HBCD injured the reproduction of B. plicatilis: The total number of offspring per female and the key population index calculated from the life table, including the intrinsic rate of population increase (rm) and net reproductive rate (R0), were significantly influenced in a concentration-dependent manner. The reproductive process was also altered, as indicated by the first spawning time, first hatching time and oocyst development time. At the same time, individual survival and growth (body length) were also negatively affected by HBCD. Reactive oxygen species (ROS) were suggested to be responsible for reproductive toxicity mainly because the total ROS contents as well as the main components of •OH and H2O2 greatly increased and resulted in the oxidative imbalance that presented as malondialdehyde (MDA) elevation. Simultaneous activation of the glutathione antioxidant system was accompanied by the apoptosis marker enzymes Caspase-3 and 9, as well as the correlation between ROS content, physiological alteration and cell apoptosis, providing further evidence for this. The integrated biomarker response (IBR) and adverse outcome pathway (AOP) showed that HBCD had a significant toxic effect on B. plicatilis near the concentration range of 96 h-LC50. The establishment of this concentration range will provide a reliable reference for future environmental concentration warning of HBCD in marine.

Metagenomics reveals the influence of small microplastics on microbial communities in coastal sediments.

The ecological impact of microplastics (MPs) in coastal environments has been widely studied. However, the influence of small microplastics in the actual environment is often overlooked due to measurement challenges. In this study, Hangzhou Bay (HZB), China, was selected as our study area. High-throughput metagenomic sequencing and micro-Raman spectrometry were employed to analyze the microbial communities and microplastics of coastal sediment samples, respectively. We aimed to explore the ecological impact of MPs with small sizes (≤ 100 µm) in real coastal sediment environments. Our results revealed that as microplastic size decreased, the environmental behavior of MPs underwent alterations. In the coastal sediments, no significant correlations were observed between the detected MPs and the whole microbial communities, but small MPs posed potential hazards to eukaryotic communities. Moreover, these small MPs were more prone to microbial degradation and significantly affected carbon metabolism in the habitat. This study is the first to reveal the comprehensive impact of small MPs on microbial communities in a real coastal sediment environment.

Research on Properties of PBAT/CaCO3 Composite Films Modified with Titanate Coupling Agent.

High cost, low crystallinity, and low-melt strength limit the market application of the biodegradable material poly (butylene adipate-co-terephthalate) (PBAT), which has become a major obstacle to the promotion of PBAT products. Herein, with PBAT as resin matrix and calcium carbonate (CaCO3) as filler, PBAT/CaCO3 composite films were designed and prepared with a twin-screw extruder and single-screw extrusion blow-molding machine designed, and the effects of particle size (1250 mesh, 2000 mesh), particle content (0-36%) and titanate coupling agent (TC) surface modification of CaCO3 on the properties of PBAT/CaCO3 composite film were investigated. The results showed that the size and content of CaCO3 particles had a significant effect on the tensile properties of the composites. The addition of unmodified CaCO3 decreased the tensile properties of the composites by more than 30%. TC-modified CaCO3 improved the overall performance of PBAT/CaCO3 composite films. The thermal analysis showed that the addition of titanate coupling agent 201 (TC-2) increased the decomposition temperature of CaCO3 from 533.9 °C to 566.1 °C, thereby enhancing the thermal stability of the material. Due to the heterogeneous nucleation of CaCO3, the addition of modified CaCO3 raised the crystallization temperature of the film from 97.51 °C to 99.67 °C and increased the degree of crystallization from 7.09% to 14.83%. The tensile property test results showed that the film reached the maximum tensile strength of 20.55 MPa with the addition of TC-2 at 1%. The results of contact angle, water absorption, and water vapor transmission performance tests showed that TC-2 modified CaCO3 increased the water contact angle of the composite film from 85.7° to 94.6° and decreased the water absorption from 13% to 1%. When the additional amount of TC-2 was 1%, the water vapor transmission rate of the composites was reduced by 27.99%, and the water vapor permeability coefficient was reduced by 43.19%.

Causes and treatment strategies of unilateral leaflet escape of bileaflet mechanical prosthetic heart valves after surgery: a case series.

BACKGROUND: During the eleven years from 2010 to 2021, preliminary statistics have shown that Fuwai Hospital completed 23,571 mechanical valve replacements for various types of valves, and 1139 mechanical valve replacements were performed in Guangyuan First People's Hospital. Only two patients developed valve leaflet escape, so valve leaflet escape is a rare postoperative complication. CASE PRESENTATION: In 2010 and 2021, two patients were selected after they had unilateral leaflet escape after having mechanical valve replacements in Fuwai Hospital of Chinese Academy of Medical Sciences and Guangyuan First People's Hospital. Both patients underwent reoperations with the classic operation and the new bileaflet mechanical prosthetic heart valve was sutured. The treatment of detached single lobe and distal vessel was comprehensively determined, and the condition was treated according to the patient's symptoms, CT results, ultrasound results and other test results, as well as whether this detached lobe caused any abnormal hemodynamics of the distal vessel. The patient with mechanical aortic valve escape completed the 10-year follow-up, and patient with mechanical mitral valve escape completed the 3-month follow-up. there was no thrombosis or hematoma at the embolic site; the patient had no lower limb symptoms. CONCLUSIONS: The reason for the leaflet escape may be related to the valve design and the leaflet material. If the detached leaflets are damaged and if the distal blood vessels are affected, simultaneous surgical treatment is required. Those patients whose vessels were not damaged by the valve lobe should be carefully monitored.

Insights into the distribution, partitioning and influencing factors of antibiotics concentration and ecological risk in typical bays of the East China Sea.

In order to obtain in-depth insight of the behavioral fate and ecological risks of antibiotics in coastal environment, this study investigated the distribution, partitioning and primary influencing factors of antibiotics in water and sediment in the East China Sea. After quantification of 77 target antibiotics in 6 categories, ten antibiotics were detected simultaneously with a detection frequency >50.0% in water and sediment; the concentrations of these ten antibiotics were 0.1-1508.0 ng L-1 and 0.01-9.4 ng g-1 in water and dry sediment, respectively. Sulfadiazine and Azithromycin (Pseudo partitioning coefficient were 28-3814 L kg-1 and 21-2405 L kg-1, respectively.) had the largest partitioning coefficient between sediment and water. In addition, pseudo partitioning coefficient of Sulfadiazine and Clindamycin were higher than the values of corresponding equilibrium partitioning constant (Kd), which would likely cause them to re-release from sediment to water. Compared to the physiochemical properties of the sediment, water quality has a greater impact on antibiotic partitioning. We found that the partitioning of antibiotics was significantly positively correlated with salinity, suspended solids, pH, NH4+-N and Zn; and negatively correlated with temperature, dissolved oxygen, PO43-, chemical oxygen demand, NO3--N, oil, Cu and Cd. The ecological risks of antibiotics in water and sediment were also evaluated for revealing their relationship with the concentration partitioning of antibiotics. Results showed that the target antibiotics mainly pose ecological risks to Daphnia with low and median chronic toxicity risk rather than fish and green algae. The antibiotics in sediment were more chronically toxic to Daphnia than that in water. The risk quotient ratio of sediment and water (RQs/RQw) ranged from 0 to 1154.0, which were exactly opposite of the values of organic carbon normalized partition coefficient (Koc), suggesting that the physical properties of antibiotics drove the ecological risk allocation of antibiotics in sediment and water.

Spatial and temporal distribution of toxic compounds in sediments and potential ecological effects on macrobenthic faunal species in Hangzhou Bay from 2003 to 2015.

The development of toxic compounds in sediment and macrobenthos species in Hangzhou bay (2003-2015) was evaluated. Concentrations were compared to Chinese sediment quality guidelines (CN-SQG) and risk assessed by the ecological risk index (ERI) and t-Distributed Stochastic Neighbour Embedding (t-SNE). To study seafood contamination, sediment and swimming crabs were collected. Chromium, copper, and arsenic exceeded CN-SQG. Organic contaminants did not exceed CN-SQG; however, t-SNE revealed a negative relationship with benthic species numbers. Since 2003, half of the benthic species have disappeared. Species sensitive to contamination were not observed after 2003-2007, while crustacea species are more tolerant: cadmium levels in crabs were 5-17 times those in the sediment, demonstrating strong bioaccumulation. These results suggest that metals and organic pollutants pose ecological and seafood risks. For good environmental management in HZB, it is important to analyze sediment, benthic biota, and seafood species for compounds known to pose toxic risks.

Fate of antibiotics in engineered wastewater systems and receiving water environment: A case study on the coast of Hangzhou Bay, China.

The occurrence of man-made antibiotics in natural environment has aroused attentions from both scientists and publics. However, few studies tracked antibiotics from their production site to the end of disposal environment. Taking the coastal region of Hangzhou Bay as the study area, the fate of 77 antibiotics from 6 categories in two-step wastewater treatment plants (WTPs, i.e. pharmaceutical WTP and integrated WTP) was focused; and the antibiotics in both dissolved and adsorbed phases were investigated simultaneously in this study. The ubiquitous occurrence of antibiotics was observed in the two-step WTPs, with antibiotic concentrations following the order of PWTP (LOQ - 1.0 × 105 ng·L-1) > IWTPi (for industrial wastewater treatment, LOQ - 3.7 × 103 ng·L-1) > IWTPd (for domestic sewage treatment, LOQ - 1.3 × 103 ng·L-1). And the types of antibiotics detected in excess sludge and suspended particles were in accordance with those in wastewater. Quinolones were invariably dominant in both dissolved and adsorbed fractions. High removal efficiencies (median values >50.0%) were acquired for the dissolved quinolones (except for DFX), tetracyclines, ß-lactams, and lincosamides. Anaerobic/anoxic/oxic achieved the highest aqueous removal of antibiotics among the investigated treatment technologies in the three WTPs. PWTP and IWTP removed 9797 and 487 g·d-1 of antibiotics, respectively; and a final effluent with 126.4 g·d-1 of antibiotics was discharged into the effluent-receiving area (ERA) of Hangzhou Bay. Source apportionment analysis demonstrated that the effluents of IWTPd and IWTPd contributed respectively 39.3% and 8.9% to the total antibiotics in the ERA. The results illustrate quantitatively the antibiotic flows from engineered wastewater systems to natural water environment, on the basis of which the improvements of wastewater treatment technologies and discharge management would be put forward.

Evaluating the Potential Antibiotic Resistance Status in Environment Based on the Trait of Microbial Community.

The overuse of antibiotics has promoted the propagation and dissemination of antibiotic resistance genes (ARGs) in environment. Due to the dense human population and intensive activities in coastal areas, the health risk of ARGs in coastal environment is becoming a severe problem. To date, there still lacks of a quantitative method to assess properly the gross antibiotic resistance at microbial community level. Here, we collected sediment samples from Hangzhou Bay (HB), Taizhou Bay (TB), and Xiangshan Bay (XB) of the East China Sea for community-level ARGs analysis. Based on the 16S rRNA genes and predictive metagenomics, we predicted the composition of intrinsic ARGs (piARGs) and some related functional groups. Firstly, a total of 40 piARG subtypes, belonging to nine drug classes and five resistance mechanisms, were obtained, among which the piARGs encoding multidrug efflux pumps were the most dominant in the three bays. Secondly, XB had higher relative abundances of piARGs and pathogens than the other two bays, which posed higher potential health risk and implied the heavier impact of long-term maricultural activities in this bay. Thirdly, the co-occurrence network analysis identified that there were more connections between piARGs and some potential pathogenic bacteria. Several piARG subtypes (e.g., tetA, aacA, aacC, and aadK) distributed widely in the microbial communities. And finally, the microbial diversity correlated negatively with the relative abundance of piARGs. Oil, salinity, and arsenic had significant effects on the variations of piARGs and potential pathogenic bacteria. The abundance-weighted average ribosomal RNA operon (rrn) copy number of microbial communities could be regarded as an indicator to evaluate the antibiotic resistance status. In conclusion, this study provides a new insight on how to evaluate antibiotic resistance status and their potential risk in environment based on a quantitative analysis of microbial communities.

Identification of the priority antibiotics based on their detection frequency, concentration, and ecological risk in urbanized coastal water.

Antibiotics have raised significant concern as emerging pollutants for their increasing consumption, persistent input, and potential threat to ecological environment. Due to low concentrations and various types in coastal water, simultaneous quantification of all kinds of antibiotics is time-consuming and costly. In order to make antibiotic regular monitoring in coastal water possible, identifying the priority antibiotics in the environment is essential. Here, a method for screening the priority antibiotics in coastal water was proposed, considering individual antibiotic concentration, the positive correlation between individual and total antibiotic concentration, the detection frequency, and obvious ecological risk. Taking coastal water of the East China Sea as an example, on a list of 77 target antibiotics, 7 (SMX, TMP, SCP, SMP, CNX, ATM, and ETM) and 4 (SMX, SCP, SMP, and CNX) antibiotics were selected to be the priority antibiotics in 2017 and 2018, respectively. Furthermore, the 4 priority antibiotics in 2018 were all involved in the 7 priority antibiotics in 2017. The sum of the priority antibiotic concentrations accounted for 0.8% and 23.2% of total antibiotic concentrations, and the sum of their RQ accounted for 69.2% and 66.8% of total RQ values in 2017 and 2018, respectively. Among the above 7 priority antibiotics, ATM is mainly used in human clinical, SMX, SCP, and SMP are mainly consumed in veterinary medicine, TMP, CNX, and ETM are commonly used for humans and animals. The proposed method might provide an important reference for the monitoring and management of antibiotic pollution in coastal water.

Antibiotics in coastal water and sediments of the East China Sea: Distribution, ecological risk assessment and indicators screening.

The distribution of 77 antibiotics in the coastal water and sediment from 3 bays of the East China Sea was investigated. There were 43 and 25 antibiotics detected with total concentrations of 30.8-2106.1 ng/L and 2.2-99.9 ng/g in water and sediment, respectively. Approximately 83.0% and 85.4% of the individual antibiotic concentrations were lower than 5.0 ng/L in water and 1.0 ng/g in sediment. Clindamycin (1.2-1507.9 ng/L, mean 183.8 ng/L) and erythromycin (ND-45.2 ng/g, mean 3.4 ng/g) were the most abundant in water and sediment, respectively. Ecological risk assessment revealed that the joint toxicity was enhanced when multiple antibiotics were present simultaneously. A decrease in the total antibiotic concentration and the ecological risk in water was observed from nearshore to offshore. Three antibiotics (sulfamethoxypyridazine, sulfamethoxazole and cinoxacin) were selected to be prioritized based on ecological risks for antibiotics monitoring and management of the coastal water in the East China Sea.

Wastewater discharge drives ARGs spread in the coastal area: A case study in Hangzhou Bay, China.

The distribution of 14 ARGs, intI1, and 16S rDNA were analysed in 4 wastewater treatment plants (WWTPs), 2 effluent receiving areas (ERAs), and Hangzhou Bay (HZB). The results showed that each integrated WWTP (IWWTP) received higher abundance of ARGs than pharmaceutical WWTPs (PWWTPs), and IWWTPs removed ARGs more efficiently than PWWTPs. The WWTP effluents greatly contributed to the ARGs pollution in the water environments of the ERAs and HZB, and the total abundance of the ARGs displayed a distance decay pattern. In coastal sediments, more ARGs were accumulated in remote sites. The correlation analysis showed that the occurrence of ARGs was more related to 16S rDNA and intI1 in the WWTPs. Three macrolides resistance genes (ermB, mphA, and vatB) had strong correlations with 16S rDNA and intI1 in all the sample groups. Our study clearly reveals the link between land WWTPs discharge and emerging pollution of ARGs in coastal environments.

Dynamics of coastal bacterial community average ribosomal RNA operon copy number reflect its response and sensitivity to ammonium and phosphate.

The nutrient-rich effluent from wastewater treatment plants (WWTPs) constitutes a significant disturbance to coastal microbial communities, which in turn affect ecosystem functioning. However, little is known about how such disturbance could affect the community's stability, an important knowledge gap for predicting community response to future disturbances. Here, we examined dynamics of coastal sediment microbial communities with and without a history of WWTP's disturbances (named H1 and H0 hereafter) after simulated nutrient input loading at the low level (5 mg L-1 NH4+-N and 0.5 mg L-1 PO43--P) or high level (50 mg L-1 NH4+-N and 5.0 mg L-1 PO43--P) for 28 days. H0 community was highly sensitive to both low and high nutrient loading, showing a faster community turnover than H1 community. In contrast, H1 community was more efficient in nutrient removal. To explain it, we found that H1 community constituted more abundant and diversified r-strategists, known to be copiotrophic and fast in growth and reproduction, than H0 community. As nutrient was gradually consumed, both communities showed a succession of decreasing r-strategists. Accordingly, there was a decrease in community average ribosomal RNA operon (rrn) copy number, a recently established functional trait of r-strategists. Remarkably, the average rrn copy number of H0 communities was strongly correlated with NH4+-N (R2 = 0.515, P = 0.009 for low nutrient loading; R2 = 0.749, P = 0.001 for high nutrient loading) and PO43--P (R2 = 0.378, P = 0.034 for low nutrient loading; R2 = 0.772, P = 0.001 for high nutrient loading) concentrations, while that of H1 communities was only correlated with NH4+-N at high nutrient loading (R2 = 0.864, P = 0.001). Our results reveal the potential of using rrn copy number to evaluate the community sensitivity to nutrient disturbances, but community's historical contingency need to be taken in account.

Occurrence and distribution of antibiotic resistance genes in the sediments of the East China Sea bays.

The coastal area of the East China Sea has experienced rapid urbanization and industrialization in China since 1980s, resulting in severe pollution of its environments. Antibiotic resistance genes (ARGs) are regarded as a kind of emerging pollutant with potential high risk. The sediment samples were collected from Hangzhou Bay (HB), Xiangshan Bay (XB), and Taizhou Bay (TB) to investigate the spatial occurrence and distribution of 27 ARGs and class I integron-integrase gene (intI1) in the coastal area of the East China Sea. The PCR results showed the frequent presence of 11 ARGs and intI1 in the sediments of the three bays. The qPCR results further showed that sulfonamide resistance was the most prevalent ARG type and antibiotic target replacement and protection were the most important resistance mechanisms in the sediments. Regarding the subtype of ARGs, sulI, tetW, and dfrA13 were the most abundant ARGs, in which sulI was higher in TB (based on both the absolute and relative abundances) and dfrA13 was higher in HB (based on the relative abundances). The network analysis revealed that intI1 had significant correlations with tetC, sulI, sulII, and blaPSE-1. Oil was the key connected factor, which had positive connections with sulI, sulII, and blaPSE-1. In addition, the joint effect of heavy metals and nutrients & organic pollutants might be crucial for the fate of ARGs in the coastal sediments.

Dynamics of Sediment Microbial Functional Capacity and Community Interaction Networks in an Urbanized Coastal Estuary.

Coastal estuaries and bays are exposed to both natural and anthropogenic environmental changes, inflicting intensive stress on the microbial communities inhabiting these areas. However, it remains unclear how microbial community diversity and their eco-functions are affected by anthropogenic disturbances rather than natural environmental changes. Here, we explored sediment microbial functional genes dynamics and community interaction networks in Hangzhou Bay (HZB), one of the most severely polluted bays on China's eastern coast. The results indicated key microbial functional gene categories, including N, P, S, and aromatic compound metabolism, and stress response, displayed significant spatial dynamics along environmental gradients. Sensitive feedbacks of key functional gene categories to N and P pollutants demonstrated potential impacts of human-induced seawater pollutants to microbial functional capacity. Seawater ammonia and dissolved inorganic nitrogen (DIN) was identified as primary drivers in selecting adaptive populations and varying community composition. Network analysis revealed distinct modules that were stimulated in inner or outer bay. Importantly, the network keystone species, which played a fundamental role in community interactions, were strongly affected by N-pollutants. Our results provide a systematic understanding of the microbial compositional and functional dynamics in an urbanized coastal estuary, and highlighted the impact of human activities on these communities.

Sediment bacterial community structures and their predicted functions implied the impacts from natural processes and anthropogenic activities in coastal area.

Coastal ecosystem structures and functions are changing under natural and anthropogenic influences. In this study, surface sediment samples were collected from disturbed zone (DZ), near estuary zone (NEZ), and far estuary zone (FEZ) of Hangzhou Bay, one of the most seriously polluted bays in China. The bacterial community structures and predicted functions varied significantly in different zones. Firmicutes were found most abundantly in DZ, highlighting the impacts of anthropogenic activities. Sediment total phosphorus was most influential on the bacterial community structures. Predicted by PICRUSt analysis, DZ significantly exceeded FEZ and NEZ in the subcategory of Xenobiotics Biodegradation and Metabolism; and DZ enriched all the nitrate reduction related genes, except nrfA gene. Seawater salinity and inorganic nitrogen, respectively as the representative natural and anthropogenic factor, performed exact-oppositely in nitrogen metabolism functions. The changes of bacterial community compositions and predicted functions provide a new insight into human-induced pollution impacts on coastal ecosystem.

Enhanced degradation of perfluorooctanoic acid using dielectric barrier discharge with La/Ce-doped TiO2.

A synergistic system of dielectric barrier discharge (DBD) combined with La/Ce-TiO2 was developed to investigate the decomposition performance of the environmentally persistent perfluorooctanoic acid (PFOA). The La/Ce-TiO2 was modified by sol-gel method and characterized by XRD, SEM, and energy dispersive X-ray. The effects of PFOA concentration, applied voltage, initial pH, liquid conductivity, and additives on the removal rate of PFOA were explored. The results showed that the La/Ce-TiO2 exhibited excellent catalytic effects on PFOA degradation in DBD system. When the applied voltage, PFOA concentration, pH value, and solution volume were 75 V, 100 mg/L, 3.63, and 1000 mL, respectively, the removal efficiency of PFOA was up to 97.5% by adding La4Ce1-TiO2 in DBD. The corresponding defluorination ratio, TOC removal, and decomposition yield were 62.2%, 57.3%, and 37 g/kWh, respectively. Furthermore, five main intermediates including CF3(CF2)6H, CF3(CF2)5COOH, CF3(CF2)5COH, CF3(CF2)4COOH, and CF3CF2CF3 were identified with LC-MS, and the degradation pathways of PFOA were proposed. The degradation mechanisms revealed that hydroxyl radicals play a significant role in the degradation of PFOA in the synergistic system.

[Distribution, sources and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Yangtze estuary and Zhejiang coastal areas].

PAHs contents of surface sediments were tested from 62 sampling sites of the Yangtze River estuary and Zhejiang coastal zone in 2013. The results showed that: 16 kinds of PAHs, which are listed as priority pollutants by EPA, were found in all the samples. The total PAHs level (dry weight) reached 31. 8-384 µg x kg(-1) and the average amount was 131.1 µg x kg(-1). The distribution of PAHs was affected by terrigenous input and point source pollution, the high-value zones were found at 2# sampling site of the Yangtze River estuary and 21# sampling site of Ningbo. Compared with other sea areas, the survey sea area was at a low PAHs pollution level. PAHs were primarily tetracyclic or tricyclic, and source analysis showed that most of PAHs were originated from combustion of wood and coal. Based on the Sediment Quality Guidelines (SQGs), the assessment result showed that the PAHs content of surface sediments from survey sea area was at a relatively low level of ecological risk; While according to the assessment result of the Sediment Quality Standards (SQSs), PAHs pollution of surface sediments from survey sea area displayed an "Obviously negative ecological effect" to some extent, and some countermeasures are required to control and eliminate pollutions.

Trace metal concentrations in suspended particles, sediments and clams (Ruditapes philippinarum) from Jiaozhou Bay of China.

Suspended particulate matter (SPM), sediments and clams were collected at three sites in Jiaozhou Bay to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 40.11-203; Zn: 118-447; Pb: 50.1-132; Cd: 0.55-4.39; Cr: 147.6-288; Mn: 762-1670 microg/g), sediments (Cu: 17.64-34.26; Zn: 80.79-110; Pb: 24.57-49.59; Cd: 0.099-0.324; Cr: 41.6-88.1; Mn: 343-520 microg/g) and bivalves (Cu: 6.41-19.76; Zn: 35.5-85.5; Pb: 0.31-1.01; Cd: 0.51-0.67; Mn: 27.45-67.6 microg/g) are comparable to those reported for other moderately polluted world environments. SPM showed a less clear pattern. Metal concentrations in sediments displayed a clear geographical trend with values increasing with proximity to major urban centers. The clams (on dry weight) showed a complex pattern due to the variability introduced by age-related factors. Cd showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations. Zn, Pb and Mn showed no clear geographical pattern, whereas Cu increased in the clams collected in the most industrialized area. In addition, the bioaccumulation factors (BAF) were calculated. The result indicated that the studied Ruditapes philippinarum in Jiaozhou Bay possessed different bioaccumulation capacities for Cd, Zn, Cu, Pb and Mn, and Cd, Zn had a relatively high assimilation of those metals from sediment particles. A significant relationship with clam age was observed for Zn (positive) and Cu (negative) suggesting different physiological requirements for both metals with age. Trace metal concentrations measured in the tissue of the investigated clam were in the range considered safe by the WHO for human use.

[Matrix-bound phosphine (PH3) distribution characteristics in the sediments of Jiaozhou Bay, China].

The distribution of matrix-bound phosphine in sediments was investigated in some selective sea areas of Jiaozhou Bay on Sep.6, 2003. Results show that the peak concentration of phosphine reachs to 143.75 ng/kg (dry weight). Moreover, an obvious regularity of distribution is observed that phosphine concentration in coastal sediments is higher than that in offshore's, and concentration within the Bay is higher than that of outside Bay. Results also reveal that phosphine concentration in such seriously polluted areas as culture farm and estuary is significantly higher than that in other investigated places. On the other hand, the relationship between phosphine and its sedimentary environment suggest that the phosphine concentration and distribution are mainly affected by the organic phosphorous, the redox potential and the sediment composition.