[Distribution and Settlement of Microplastics in the Surface Sediment of Yangtze Estuary].

This study is designed to understand the microplastic contamination in the coastal area of Yangtze estuary. The abundance and distribution profiles of microplastics in the surface sediment of six sampling sites along the Yangtze estuary were examined throughout one year. The detected average concentration of microplastic, including fibers and fragments, in the surface sediment of Yangtze estuary was (3.42±1.31) items ·g-1 (DW). Sampling during four seasons, in the months of January, April, July, and November, indicated that the highest abundance of microplastics in Yangtze estuary surface sediment occurred in January. A re-suspension experiment showed that microplastics tend to settle in the surface sediment after re-suspension. The distribution and settlement of microplastics along the coastal area has a high concordance with the dynamic erosion-accretion process of the Yangtze estuary. Microplastics tend to settle in accretion sites rather than in erosion sites.

Developmental toxicity and molecular responses of marine medaka (Oryzias melastigma) embryos to ciguatoxin P-CTX-1 exposure.

Ciguatoxins are produced by toxic benthic dinoflagellates and cause ciguatera fish poisoning worldwide, but the toxic effects on developing marine fish have not been well investigated. The Pacific ciguatoxin (P-CTX-1), is a potent sodium channel agonist, which is one of the most toxic members among all CTXs. This study evaluated the toxic effects of microinjecting purified Pacific ciguatoxin-1 (P-CTX-1) on embryonic development of marine medaka Oryzias melastigma. A lower 96h-LD50 value was estimated for eleuthero-embryos (1.32ngg-1) than that for embryos (1.71ngg-1), indicating that P-CTX-1 is more lethal to newly hatched medaka larvae. P-CTX-1 induced detrimental effects during embryonic development, including hatching failure, abnormalities in physical development (caudal fin malformation and spinal deformities), internal damage (green coloration of the gall bladder and hemorrhaging), immune dysfunction, and altered muscle physiology (bradycardia and hyperkinetic twitching). The results of a transcriptional expression analysis of genes related to the stress/immune responses, cardiac and bone development, and apoptosis supported the observed developmental abnormalities. This study advanced the understanding of P-CTX-1 mediated toxic mechanisms in the development of early life stages of a fish, and thus contributed to the toxicity assessment of CTXs in marine ecosystems.

[Physicochemical Properties and Antibacterial Effect of Silver Nanoparticles: A Comparison of Environmental and Laboratorial Conditions].

This study aimed to understand how the physicochemical properties of silver nanoparticles (AgNPs) affected its toxicity in the aquatic environment. The morphologies of oleylamine-coated AgNPs (4 nm) under environmental and laboratory water conditions were studied under transmission electron microscopy, and the results showed oleylamine-coated AgNPs formed big aggregates in the environmental water samples after 12 h equilibration. Dynamic light scattering results also showed that oleylamine-coated AgNPs had larger hydrodynamic size in all water samples as compared to its primary size (4 nm). Exposure to oleylamine-coated AgNPs inhibited the growth of Bacillus subtilis (B. subtilis) and reduced its cell viability in Luria-Bertani (LB) broth and 0.85% NaCl, respectively. A dose-dependent toxicity of AgNPs in B. subtilis was observed in laboratorial medium conditions but not in environmental water condition. Low concentration of AgNPs exhibited lower toxicity in environmental water samples as compared to that in laboratorial medium conditions. Separating AgNPs from bacterial suspension through a dialysis membrane enhanced the cell viability of B. subtilis significantly. In the environmental water samples, the AgNPs-bacteria interaction would be reduced with the formation of big aggregates by AgNPs, which consequently decreased its toxicity in aquatic environment.

[Contribution of Particle Size and Surface Coating of Silver Nanoparticles to Its Toxicity in Marine Diatom Skeletonema costatum].

Due to the unique antibacterial properties, silver nanoparticles (AgNPs) have been widely used in commercial applications. In this study, the toxicity of three kinds of AgNPs with different sizes and surface coatings to marine diatom Skeletonema costatum (S. costatum) was studied, which was one of the dominant species in estuarine and coastal areas. All three kinds of tested AgNPs inhibited the growth of exposed S. costatum under acute exposure condition, and the order of toxicity was 10 nm-OA > 10 nm-PVP > 20 nm-PVP. Given the condition of similar particle size, oil amine surface coated AgNPs were more toxic than polyvinyl pyrrolidone (PVP) surface coated AgNPs in S. costatum in term of cytotoxicity. With the same surface coating, the toxicity of AgNPs in S. costatum was affected by its hydrodynamic diameter and exposure concentrations. When the concentration of AgNPs was less than 500 µg · L⁻¹, larger sized AgNPs showed greater toxicity; When the concentration was greater than or equal to 500 µg · L⁻¹, smaller AgNPs exhibited greater toxicity. At molecular level, 50 µg · L⁻¹ 10nm-PVP significantly upregulated expression level of 3HfcpA (P < 0.05) and significantly downregulated expression level of Dl (P < 0.05), and 500 µg · L⁻¹ 10nm-OA significantly upregulated 3HfcpA expression (P < 0.05), while 20 nm-PVP treatment group didn't show any significant change. Exposed diatom demonstrated sensitive photosynthesis response to small size and PVP coated silver nanoparticles at molecular level. This study suggested that the toxicity of AgNPs to marine microalgae was largely controlled by the particle size, surface coating, exposure medium, exposure concentration and other factors. The smaller the particle size, the greater the toxicity of AgNPs, and the particle size of AgNPs played an important role in the toxicity of AgNPs in marine diatom S. costatum.

Effects of pre-harvest chemical application on rice desiccation and seed quality.

Pre-harvest desiccation may increase the efficiency of seed production. Field studies were conducted to determine the effects of diquat, paraquat, and ethephon applications on grain moisture, grain weight, and seed germination of hybrid rice Yanliangyou 88 (Oryza sativa ssp. indica) and conventional rice Wuyunjing 7 (Oryza sativa ssp. japonica). In 2013, we tested 12 treatments applied at four weeks (Yanliangyou 88) and six weeks (Wuyunjing 7) after heading. Results showed that reductions in moisture content were significant two and four days after chemical application. Chemical applications had no adverse effects on 1000-grain weight, germination percentage, or germination index, but there were negative effects on the percentage of normal seedlings. Desiccation effects increased with increase in the period after application, while the effect of ethephon combined with diquat or paraquat on desiccation was limited compared with that of diquat or paraquat alone in a short period after application. In 2013, chemical applications reduced the moisture content by from 0.5% to 6.4%, the germination percentage by from 0% to 3.3%, and the percentage of normal seedlings by from 13.3% to 100.0%. Among the treatments, diquat applied at 120 g/ha resulted in effective desiccation with fewer negative effects on grain weight and seed germination in 2013 and 2014. Therefore, diquat may have potential as a pre-harvest chemical desiccation treatment for rice. These results may provide a basis for developing and implementing protocols for large scale field trials.

Assessing Adverse Effects of Aroclor 1254 on Perinatally Exposed Rat Offspring.

To assess the neurotoxic effects and redox responses of Aroclor 1254 (A1254) on perinatally exposed rat offspring, A1254 was administered by gavage from gestational day (GD) 6 to postnatal day (PND) 21. Neurobehavioral development, antioxidant enzyme activities, lipid peroxidation (LPO), nitric oxide (NO), and NO synthase (NOS) levels were analyzed in the offspring. Neurobehavioral development analysis revealed delayed appearance of the righting reflex, negative geotaxis, and cliff drop test responses in A1254 exposed group. Developmental A1254 exposure also caused oxidative stress in the brain of PND 22 offspring via reductions in the activity of SOD and GSH-Px, and by promoting a rise in the levels of NO and NOS.

[Size distribution characteristics of particulate mercury on haze and non-haze days].

With the rapid economic development, China suffers from the severe haze and atmospheric mercury pollution. Particulate mercury transport has an important significance in its global cycle. In order to investigate the distribution characteristics of particulate mercury, 12 degrees Nano-moudi (6.2-9.9 µm, 3.1-6.2 µm, 1.8-3.1 µm, 1.0-1.8 µm, 0.56-1.0 µm, 0.32-0.56 µm, 0.18- 0.32 µm, 0.10-0.18 µm, 0.056-0.10 µm, 0.032-0.056 µm, 0.018-0.032 µm, 0.010-0.018 µm) impactor was used to measure the size distributions of atmospheric particulate mercury on both haze and non-haze days in Shanghai. The results indicated that particulate mercury levels were positively correlated with those of the particles. The average concentration of particulate mercury (0.31 ng x m (-3)) on haze days was 2-3 times than that on non-haze days (0.11 ng x m(-3)). The mass size distributions of aerosols and particulate mercury showed bimodal distributions. The peak shifted from 0.56-1.0 µm and 3.1-6.2 µm on haze days to 0.32-0.56 µm and 3.1-6.2 µm on non-haze days. The particles with aerodynamic diameter smaller than 1 µm which could stay for a long time and transport for a long distance, had higher particulate mercury concentrations. The average contribution of particulate mercury to total PM aerosol were higher on haze days (0.029 ng x µg(-1)) than on non-haze days (0.015 ng x µg(-1)), indicating that secondary particles typically grew faster than mercury during the haze pollution events. The particulate mercury concentration in accumulation mode was 2.06 ng x m(-3) on haze days, while it was 0.55 ng x m(-3) on non-haze days. The large increase of the accumulation mode particles was a main reason for the formation of haze. Emissions from the coal burning as well as road surface dust and dust from long-range transport accounted for the serious pollution on haze days.

[Ecological risk evaluation of heavy metals of the typical dredged mud in Shanghai].

In order to discuss the potential ecological risk of heavy metals of the typical dredged mud in Shanghai, the Hakanson potential ecological risks method was used to analyse and assess the potential ecological risks of heavy metals, including Hg, Cd, Cu, Pb, As,Cr and Zn in dredged mud from the following three areas-the dock apron of Huangpu River, the mouth of the Yangtze River and inland waterways. The results showed that the mean values of ecological risk index (Er(i)) of the seven heavy metals are 20.05, 17.49, 8.82, 5.71, 4.68, 1.74 and 1.13, respectively, all of which belonged to the low ecological risk; Cd (one location in inland waterways) and Hg (three locations in the mouth of the Yangtze River and one location in inland waterways) are the most hazardous elements, with the Er(i) > 40, which belonged to the medium ecological risk or the high ecological risk, and other elements belonged to the low ecological risk. From the results of ecological risk indices(ERI) of the heavy metals in Shanghai dredged mud, the risk of the heavy metals belonged to the low ecological risk. The ERI of inland waterways, the mouth of the Yangtze River and the dock apron of the Huangpu River were 81.4, 57.7 and 52.5, respectively, which all belong to the low ecological risk.

[Assessment and correlation analysis of heavy metals pollution in soil of Dajinshan Island].

The Dajinshan Island is the highest altitude point in the nature land of Shanghai. In order to find out the status of soil heavy metals pollution of the Dajinshan Island and its correlation, this paper used the methods of grid and serpents sampling to collect samples, and applied the single factor pollution index method and potential ecological harm index method to assess the pollutions status. The results showed that the main contributor of soil heavy metal pollution in Dajinshan Island was Cd, with an over-standard rate of 85.4%, followed by Pb, with an over-standard rate of 26.8%, whereas Zn and Cu were not excessive. In addition, there was significant positive correlation between Pb-Cu, Pb-Zn and Cu-Zn at the level of P = 0.05, suggesting that they had high homology and were easily influenced by the soil forming materials. This was an indirect evidence that the Dajinshan Island was well protected and not much affected by human activities.

[Development of direct competitive enzyme-linked immunosorbent assay for the determination of domoic acid].

To develop a direct competitive enzyme-linked immunosorbent assay (ELISA) for rapid detection of domoic acid concentrations, HRP (horse radish peroxidase) was successfully linked to DA using EDC. The concentration of DA was quantitatively analyzed on the basic of the specific immune responses between the DA- HRP and the monoclonal antibodies made in advance. Calibration curve were established after the optimization of reaction conditions such as the type of blocking solution, the blocking time and the incubation temperature. The results show that, the best reaction condition of the direct competitive ELISA is 1% gelatin, blocking 1 h at 37 degrees C, incubating 1 h at 37 degrees C after the monoclonal antibodies added. The detect limit is 3.58 ng x mL(-1), the coefficient of variation between the holes is below 15%, and the recovery is 80% - 120%. The whole analysis process could be completed within 1.5 h. It meets the requirements of rapid and batch detection of domoic acid. The method will have broad development prospects.

[Reconstruction of urban land space based on minimum cumulative resistance model: a case study of Xintang Town, Guangzhou City].

Based on the source-sink landscape theory and the principles of ecosystem services, the minimum cumulative resistance (MCR) model was modified, where the urban center construction land was taken as the expansion source, and the contribution rate of ecological land ecosystem services value was considered as the resistance coefficient. With the modified MCR, the urban spatial expansion process of Xintang Town, Guangzhou City was successfully simulated, and, based on the protection of ecological security pattern, the optimum path for reconstructing urban land space was put forward. The simulated urban spatial expansion short path in 1988-2008 was in accordance with the real situation. By the modified MCR, the urban space was divided into four zones of high, higher, medium, and low resistance, with the area of 80.84, 78.90, 24.26, and 61.88 km2, respectively. The expansion path of the urban space was along the route from low to medium and then to high resistance zones successively. The land suitable for eco-protection and construction had an area of 159.74 km2 and 86.14 km2, while the ecological conflict area (17.37 km2) was mainly located in higher and high resistance zones, being 10.38 and 6.99 km2, respectively. The modified MCR could not only effectively reflect the distribution area of urban land use and the conflict relationship between urban construction and ecological protection, but also reasonably judge the best developmental short path for urban spatial expansion.

Rapid monitoring of mercury in air from an organic chemical factory in China using a portable mercury analyzer.

A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m(3) in air over the contaminated area provided evidence of the mercury transformation to volatile Hg(0). Mercury analysis of soil and plant samples demonstrated that the mercury concentrations in soil with vaporized and plant-absorbable forms were higher in the southern area, which was closer to the factory. Our results suggest that air monitoring using a portable mercury analyzer can be a convenient and useful method for the rapid detection and mapping of mercury pollution in advanced field surveys.

[Correlation analysis between the PM2.5, PM10 which were taken in the hazy day and the number of outpatient about breathing sections, breathing sections of pediatrics in Shanghai].

In order to explore the correlation between the concentration of PM10, PM2.5 which were taken during the day of haze pollution and the average number of outpatient service, pediatrics. Based on the date with the number of pediatric outpatient and the concentration of PM2.5, PM10 which were taken form the haze days on 1 January 2009 - December 31 in 6 hospital in shanghai such as xinhuan hospital, we analyzed the data and executed the risk evaluation. The results showed that: in the haze day, when the average concentration of PM10 increase 50 microg/m3, the average number of the outpatient service and pediatric clinic increased 3% and 0.5%, when the average concentration of PM2.5 increase 34 microg/m3, the average number of the outpatient service and pediatric clinic increased 1.9% and 3.2%, Also, the pollution of PM10 and PM2.5 has a larger cumulative effects on the number of outpatient service. And the accumulation effect will be To maximize after 6 days behind the haze pollution. Thus, PM2.5, PM10 which were taken during the haze of pollution in shanghai, has certain influence on the average number of outpatient service, pediatric clinic.

[Development of colloidal gold immunochromatographic strip for rapid detection of domoic acid].

The colloidal gold immunochromatographic test strip was developed in order to establish a rapid detection assay of Domoic acid (DA) content in marine shellfish. The colloidal gold with particle diameter 20 nm was obtained by reducing gold chloride with sodium citrate. After identification by electron micrograph, optimum conditions for labeling were determined and colloidal gold was labeled by DA monoclonal antibody. The gold-labeled antibody was coated on some chosen glass fiber and dried. The coating antigen (DA-BSA) and Goat anti Mouse IgG were spotted respectively on a piece of nitrate fiber membrane as test line and control line. Finally the test strips were constructed and the detection sensitivity was measured. The results showed that, the detection limit of colloidal gold immunochromatographic test strip was 20 ng/mL and the whole analysis process could be completed within 15 min. The method established is sensitive and the procedure of determination is simple and quick without special equipment. The colloidal gold immunochromatographic test strip could be widely used for batch detection of domoic acid in shellfish on site and has great prospect for commercial development.

[Rapid biochemical method for the detection of paralytical shellfish poisoning toxins in shellfish from seafood market].

A rapid biochemical method was discussed in order to detect low concentration of paralytic shellfish poisoning (PSP) in sea food. The mice were injected with PSP extract of bivalves (1 and 0.2 microg/kg respectively, as STX equivalents) purchased from seafood market. ACh, AChE, NO and NOS in blood were studied at 15, 60, 120 min respectively. The results showed that at low dose (0.2 microg/kg) and 15 min, only the contents of ACh changed significantly compared with control group (p < 0.05), which was (141.2 +/- 14.8) microg/mg, while the contents of NO and the activities of NOS changed until 120 min, compared to control group (p < 0.05) ,which were (68.7 +/- 3.8) micromol/g and (40.1 +/- 4.9) U/mg respectively. At high dose the contents of ACh changed at all three time point. It can be suggested that the contents of ACh is the only one of four indexes which can response to PSP at low dose in an early stage (15 min) and may be selected as a biochemical index for rapid detection of PSP.

Distribution, sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources from Henan Province in middle of China.

Distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources have been carried out for the first time in Henan Province, China. Water samples collected from four river systems and their tributaries, as well as groundwater resources, were analyzed according to EPA method 525.2. Total of 68 water samples were collected in 18 cities in Henan province in May, August and November, 2001. Concentrations of sum of 16 priority PAHs in water samples ranged from 15 to 844 ng/L with a mean value of 178 +/- 210 ng/L (n = 68). The spatial and temporal distribution of PAHs showed that the Huanghe and the Huaihe river systems had relatively higher concentrations of total PAHs. Higher concentrations of total PAHs were observed in August and November than in May, with respective mean values of 262, 232 and 33.6 ng/L. Ratios of Ant/(Ant + Phe) and Flur/(Flur + Pyr) were calculated to evaluate the possible sources of PAH contamination, which indicated that the coal combustion sources were the main contributors to PAHs in most drinking water resources. Some petrogenic (or pyrolytic) sources of PAHs were also found. The toxic equivalency factors (TEFs) were used to calculate benzo[a]pyrene equivalents (BaPE) for water samples. The average value of BaPE was 0.6 ng/L. The values in most stations were much lower than the guideline values in drinking water of Chinese Environmental Protection Agency (CEPA, 2.8 ng/L) and the US Environmental Protection Agency (US EPA, 200 ng/L). Overall, the drinking water resources in Henan province showed some carcinogenic potential.

[Correlation of polycyclic aromatic hydrocarbons (PAHs) in PM10- phoenix tree leaves-soil system of a coking & chemical factory in Shanghai].

In order to study the distributions characteristics, sources and relationship of PAHs in PM10- phoenix tree leaves-soil system of a coking & chemical factory in Shanghai, the samples of PM10, phoenix tree leaves and soil around the factory were collected for a year. The concentration of PAHs were analyzed according to the USEPA method 8 000 series. The results showed that the average concentration of PAHs in PM10, phoenix tree leaves and soil were 101.11 ng/m3, 79.45 ng/g and 121.53 microg/g, respectively. Particulate phase (PM10) contained mainly carcinogenic and mutagenic PAHs, among which BaA, BghiP, Flu and BaP were found at significant concentrations. In phoenix tree leaves, Nap,Chy, BaP and BghiP presented a higher level of concentration. In soil, 3 and 4-ring PAHs presented a higher level. PAHs concentrations of phoenix tree leaves were very lower in May. Only Ace (0.16 ng/g) and Pyr (0.63 ng/g) were detected. In July and August the concentrations (39.19 ng/g and 150.94 ng/g, respectively) were uplifted significantly. It could be concluded PAHs was from petroleum and coal-fired compound source. There were very strong positive relationships of 16 PAHs level among phoenix tree leaves, soil and PM10 (p < 0.01).

Polychlorinated biphenyls (PCBs) in PM10 surrounding a chemical industrial zone in Shanghai, China.

In order to gain comprehensive understanding of status, properties and sources of PCBs pollution at an industrial area in Shanghai, PM10 were collected during the period November 2004-September 2005. The results showed that the mean value of total PCBs in the industrial area was 2,017.22 pg m(-3). Three dioxin-like PCB congeners had a mean value of TEQ of 0.24 pg-TEQ m(-3). The concentrations of PCBs at all sites were higher in colder months than in warmer months. SigmaPCB concentrations were correlated positively with SO2, NO2 and OCPs, while negatively with polycyclic aromatic hydrocarbons (PAHs), ambient temperature, rainfall and wind speed. It could be concluded that the area had been contaminated by PCBs from a local source.

Consumption of mercury-contaminated rice induces oxidative stress and free radical aggravation in rats.

OBJECTIVE: To study the oxidative stress induced by consumption of mercury-contaminated rice in rats, and to assess the possible public health risk of mercury contamination in Wanshan mining area. METHODS: Sprague Dawley rats were fed the mercury-contaminated rice produced from Wanshan area for 90 days. The antioxidant status and the free radicals in rat serum were evaluated. RESULTS: High mercury accumulation in organs of rats fed the mercury-contaminated rice confirmed the server pollution of mercury in Wanshan mining area. The intensity of electron spin resonance (ESR) signal increased by 87.38% in rats fed the rice from Wanshan compared with that in the control rats fed the rice from Shanghai, suggesting that chronic dietary consumption of rice from mercury mining area could induce an aggravation of free radicals. Feeding the mercury-contaminated rice was associated with significant decreases in the antioxidant enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and concentration of serum nitric oxide (NO), but it had no effect on serum nitric oxide synthase (NOS) activity. Feeding the mercury-contaminated rice raised the level of serum malonyldialdehyde (MDA), indicating the occurrence of oxidative stress. CONCLUSION: The long-term dietary consumption of mercury-contaminated rice induces the aggravation of free radicals and exerts oxidative stress.

Expression of c-fos and oxidative stress on brain of rats reared on food from mercury-selenium coexisting mining area.

Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of malondialdehyde (MDA), superoxide dismutase (SOD), GSH-peroxidase (GSH-px) and Glutathione (GSH) in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (P<0.01). It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes (IEGs); free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food.