Accumulation of petroleum hydrocarbons and heavy metals in clams （Ruditapes philippinarum） in Jiaozhou Bay, China

Accumulation and distributions of aliphatic and polyaromatic hydrocarbons (PAHs) and heavy metals were measured in tissues of the clam Ruditapes philippinarum collected from 5 sites in Jiaozhou Bay, Qingdao, China. The concentrations of total aliphatic hydrocarbon and PAHs ranged from 570 to 2 574 ng/gdw (gram dry weight) and from 276 to 939 ng/gdw, in the most and least polluted sites, respectively. The bio-accumulation of hydrocarbons and PAHs in the clams appeared to be selective. Aliphatic hydrocarbons were predominantly represented by short chain (<nC₂₃) n-alkanes, suggesting that petroleum hydrocarbons were likely the major contamination source. The selective uptake of 3 and 4 ring PAHs, such as naphthalene, fluorene, phenanthrene, fluoranthene and pyrene, by the clams was probably related to the physiological and bio-kinetic processes that were energetically favorable for uptake of compounds with fewer rings. Accumulation of the metals Cd, Cu, Zn, Pb, Cr, Hg, and As in the clam tissues also showed high variability, ranging from 0.043 to 87 μg/gdw. Among the 7 detected metals, Zn, Cd, Cu, and As had a particularly high potential of accumulation in R. philippinarum. In general, a positive correlation was found between the tissue concentrations and sediment concentrations of hydrocarbons and of some metals. Our study suggests that moderate contamination with polyaromatic hydrocarbons, and low to moderate contamination with metals, currently exists for clam R. philippinarum in Jiaozhou Bay, in comparison with other regional studies. A long-term monitoring program is certainly needed for assessment of the potential ecological influence and toxicity of these contaminants of R. philippinarum in Jiaozhou Bay.     

Biosorption of Cr (VI), Cr (III), Pb (II) and Cd (II) from aqueous solutions by Sargassum wightii and Caulerpa racemosa algal biomass

Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr(VI),Cr(III),Pb(II) and Cd(II) by algal biomass obtained from algae Sargassum wightii(brown) and Caulerpa racemosa(green).Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr(VI),Cr(III),Pb(II) and Cd(II) ions.C.racemosa exhibited 85% biosorption of Cd(II) and Cr(VI),and 50% biosorption of Cr(III) and Pb(II).The results of our study suggest that seaweed biomass can be used efficiently for     

武汉市东西湖区主要湖泊表层沉积物重金属污染特征与生态风险评价

人类活动对水环境影响巨大,同时水环境影响着人类的生产生活。采用地质累积指数法及潜在生态危害指数法对武汉市东西湖区主要湖泊表层沉积物重金属情况展开评价发现东西湖主要湖泊表层沉积物平均污染程度处于相对较低水平。地累积指数法评价结果表明,东大湖和金湖中Cd元素处于中度污染水平累积,墨水湖和上金湖中Cd元素为偏中度污染累积水平,其他湖泊沉积物中重金属均处于轻度或无污染水平。潜在生态危害指数法评价结果表明金湖和东大湖沉积物中重金属的潜在风险处于重度生态风险水平,墨水湖、上金湖、下银湖处于中度风险水平,其余湖泊沉积物中重金属的潜在风险均处于低风险水平。主成分分析表明,Hg、Cr、Ni、Cu、Zn、Cd、Pb可能来自于工业和交通源的排放,而As可能与农药的使用有关。后期金湖、东大湖、墨水湖、上金湖和下银湖的内源污染治理过程中需考虑重金属的生态风险问题。      

DYNAMIC CHANGES OF INORGANIC NITROGEN AND ASTAXANTI—IIN ACCUMULATION IN HAEMATOCOCCUS PLUVIALIS

This study on dynamic changes of culture color,astaxanthin and chlorophylls,inorganic N including N-NO3^-,N-NO2^- and N-NH4^ in batch culture of Haematococcus pluvialis exposed to different additive nitrate concentration showed(1)ast/chl ratio was over 0.8 for brown and red algae,but was usually less than 0.5 for green and yellow algae;(2)N-NO3^-,in general,was unstable and decreased,except for a small unexpected increase in nitrate enriched treatment groups;(3)measurable amounts of N-NO2^- and N-NH4^ were observed respectively with three change modes although no extemal nitrite and ammonia were added into the culture;(4)a non-linear correlation between ast/chl ratio(or color)changes and the levels of N-NO3^-,N-NO2^-,N-NH4^ in H.pluvialis culture;(5)up and down variation of the ast/chl ratio occurred simultaneously with a perceptible color change from yellow to brown(or red)when N-NO3^-,N-NO2^- and N-NH4^ fluctuated around 30,5,5μmol/L respectively;(6)existence of three dynamic modes of N-NO3^-,N-NO2^- and N-NH4^ changes,obviously associated with initial extemal nitrate;(7)the key level of total inorganic N concentration regulating the above physiological changes during indoor cultivation was about 50 μmol/L;and(8)0.5-10mmol/L of nitrate was theoretically conducive to cell growth in batch culture.     

DISTRIBUTION OF LEAD IN URBAN SOIL AND ITS POTENTIAL RISK IN SHENYANG CITY, CHINA

1INTRODUCTION The ubiquitous distribution and known toxicity of lead pollution in urban environment are posinggreat concern, in term of human health and environment (JULIE and ALEX, 2001). In recent years various human activities, such as automobile exhaust, waste disposal, paint, lead smelting and refining, battery disposal, as well as coal and fuel combustion have implied notable contributions to the increase of environmental lead concentration (SUTHERLAND et al., 2003). Pb is an…     

Studies on color type variants from mutagenized protoplasts ofPorphyra haitanensis Chang et Zheng &P. Yezoensis ueda (rhodophycease)

Isolated protoplasts from thalli ofPorphyra haitanensis andPorphyra yezoensis were treated with colchicine or irradiated by ultraviolet (UV). Several types of color variants were observed among the protoplast offspring. After treatment with colchicine: (1) 0.04–0.09% of red type variants inP. haitanensis were obtained; (2) The rate of red type variants and the variegated chimeral thalli composed of red type and wild type of sectors were 0.31–1.11% inP. yezoensis. After irradiation with UV: (1) 3.5–10.5% of red type variants inP. yezoensis were obtained: (2) 0.5–2.0% of red type variants and the variegated chimeral thalli composed of red type and wild type of sectors were obtained inP. haitanensis. Colchicine and UV’s mutangenic effects onP. yezoensis protoplasts were stronger than those onP. haitanensis protoplasts. The most efficient concentration of colchicine was 0.05%. The optimal length of UV-radiation was 1/2 min (radiation distance 5 cm). The red type variants induced by colchicine treatment grew faster than the wild type thalli. The clones of vegetative propagation from protoplasts of red type variants were still red type thalli. The red type variants will be good materials for genetic studies and improvement ofPorphyra strains.     

Effects of heavy metals （Pb^2＋ and Cd^2＋） on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb²⁺ and Cd²⁺ (0, 0.5, 1, 2, 4, 6 and 8 mg/L). The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased (>4 mg/L Pb²⁺) metal concentration. The photosynthetic apparatus (thylakoid membranes) were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration (8 mg/L Pb²⁺), the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations (0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L Pb²⁺), both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents (chlorophyll α, β carotene and phycocyanin) were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb²⁺, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll α, β carotene and phycocyanin respectively over the control. Corresponding reductions for the same Cd²⁺concentrations were 57.83, 48.94 and 56.90%. Lethal concentration (96 h LC₅₀) values (3.47 mg/L Cd²⁺ and 12.11 mg/L Pb²⁺) indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd²⁺ than Pb²⁺. Supported by the Chinese Scholarship Council     

Tolerance of ciliated protozoan Paramecium bursaria （Protozoa,Ciliophora） to ammonia and nitrites

The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in order to determine the lethal concentrations. Linear regression analysis revealed that the 2h-LC50 value for ammonia was 95.94 mg/L and for nitrite 27.35 mg/L using probit scale method (with 95% confidence intervals). There was a linear correlation between the mortality probit scale and logarithmic concentration of ammonia which fit by a regression equation y=7.32x-9.51 (R^2=0.98; y, mortality probit scale; x, logarithmic concentration of ammonia), by which 2 h-LC50 value for ammonia was found to be 95.50 mg/L. A linear correlation between mortality probit scales and logarithmic concentration of nitrite is also followed the regression equation y=2.86x 0.89 (R^2=0.95; y, mortality probit scale; x, logarithmic concentration of nitrite). The regression analysis of toxicity curves showed that the linear correlation between exposed time of ammonia-N LC50 valueand ammonia-N LC50 value followed the regression equation y=2 862.85e-0.08x (R^2=0.95; y, duration of exposure to LC50 value; x, LC50 value), and that between exposed time of nitrite-N LC50 value and nitrite-N LC50 value followed the regression equation y = 127.15e-0.13x (R^2=0.91; y, exposed time of LC50 value; x, LC50 value). The results demonstrate that the tolerance to ammonia in P. bursaria is considerably higher than that of the larvae or juveniles of some metozoa, e.g. cultured prawns and oysters. In addition, ciliates, as bacterial predators, are likely to play a positive role in maintaining and improving water quality in aquatic environments with high-level ammonium, such as sewage treatment systems.     

Food sources of the Manila clam Ruditapes philippinarum in intertidal areas: evidence from stable isotope analysis

Based on stable isotope analysis, we characterized the dietary regime of the Manila clam Ruditapes philippinarum inhabiting intertidal areas along the Liaodong Peninsula, Northern China. Samples, including particulate organic matter (POM; n =30), benthic microalgae (BMI; n =30) and R. philippinarum (n =60), were collected from six sampling sites displaying the same ecological conditions. Of the two primary food sources, POM was more depleted in δ ¹³C (?20.61‰ to ?22.89‰) than BMI was (?13.90‰ to ?16.66‰). With respect to ¹⁵N, BMI was more enriched (2.90‰ to 4.07‰) than POM was (4.13‰ to 5.12‰). The δ ¹³C values of R. philippinarum ranged from ?18.78‰ to ?19.35‰ and the δ ¹⁵N values from 7.96‰ to 8.63‰, which were intermediate between the POM and BMI values. In a two-source isotope mixing model, we estimated the relative contributions of POM and BMI to the diet of R. philippinarum to be 74.2% and 25.8%, respectively. We conclude that R. philippinarum feeds mainly on POM, and BMI is also an important supplemental food source in intertidal areas.     

Isolation of protoplasts from <Emphasis Type="Italic">undaria pinnatifida</Emphasis> by alginate lyase digestion

The aim of this study is to isolate protoplasts from Undaria pinnatifida. Protoplasts of the alga were isolated enzymatically by using alginate lyase, which was prepared by fermenting culture of a strain Vibrio sp. 510. Monofacterial method was applied for optimizing digestion condition. The optimum condition for protoplast preparation is enzymatic digestion at 28°C for 2h using alginate lyase at the concentration of 213.36 U (8 mL) every 0.5g fresh thalline with NaCl 50 and at the shaking speed of 150 r min⁻¹ during digestion. The protoplast yield can reach 2.62±0.09 million per 0.5 g fresh leave under the optimum condition. The enzyme activity is inhibited by Ca²⁺ and slightly enhanced by Fe²⁺ and Mn²⁺ at concentrations of 0.05, 0.08 and 0.10 mol L⁻¹.     

Disease resistance and humoral immunomodulatory effects of vitamin C on grouper,Epinephelus awoara

The disease resistance and humoral immunomodulatory effects of vitamin C administered orally to grouper,Epinephelus awoara maintained on a frozen fish diet supplemented with vitamin C at 500, 1000, 1500 and 2000 mg/kg were investigated. After 20 weeks, the growth rates of the groups with high level of vitamin C apparently increased. The untreated fish had symptoms of vitamin C deficiency. The endogenous liver tissue vitamin C levels were found to reflect well the dietary treatments. After intraperitoneal injection or bath challenge with a virulent strain ofVibrio vulnificus, fish fed with high level vitamin C showed significantly higher survival rate compared with the normal control group. Vaccination with formalin inactivatedV. vulnificus significantly enhanced the specific antibody production in fish treated with vitamin C, and completely protected from strong bacterial challenge the groups fed on fish with vitamin C 1500 and 2000 mg/kg diet. Project 39500113 supported by NSFC and also by Guangdong Science Research Foundation (Grant No. 950711).     

Study on the relationship between speciation of heavy metals and their ecotoxicity

Heavy metal is a main pollutant in the marine ecosystem, so study on the effect of heavy metal on phytoplankton is important. Algae (Chaetoceros sp.,Dunaliella sp.,Dicrateria zhanjiangenis Hu. var. sp.) were laboratory cultured to observe the effect of heavy metals on their growth. The effect of different metal ion concentration, the detoxication effect of complexation agents and the growth of algae in different media and different nutrition levels were studied to evaluate the effect of metal speciation. It is proved that trace amount of heavy metals can stimulate the growth of algae cells but that high concentration is lethal. The sequence of toxicity is Cd²⁺>Zn²⁺>Pb²⁺. In ordinary nutrition conditions, the detoxication sequence of complexation agents toChaetoceros sp. is EDTA >sodium salicylate>sodium oxalate >sodium citrate>sulfanilic acid>O-phenanthroline. This is in good conformity with the stability constant sequence of these agents with copper and good evidence that toxicity of metal ion is related to its activity and not to its total concentration. Project supported by the Fund of Excellent Young Teachers of State Educational Commission of China.     

Use of antioxidant enzymes of clam <Emphasis Type="Italic">Ruditapes philippinarum</Emphasis> as biomarker to polycyclic aromatic hydrocarbon pollution

The typical organic pollutant polycyclic aromatic hydrocarbon (PAH) anthracene was selected as a contaminant to investigate its effects on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum (visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.     

Iodine content ofSargassum in Southern China

Sodium thiosulphate and neutron activation determination of iodine content in samples of 18Sargassum species collected in Guangdong and Guangxi Province in April 1996 showed large differences (0.47×10⁻³ inSargassum hemiphyllum, 0.56×10⁻³ inSargassum assimile, and 4.5×10⁻³ inSargassum vachellianum). Traditional titration analysis and neutron activation analysis for determination of total iodine yielded similar results showing that certainSargassum species had high capacity to accumulate iodine. Contribution No. 3162 from the Institute of Oceanology, Chinese Academy of Sciences. The project was supported by the National Ninth Five-Year Plan of China (No. 96-916-04-01).     

Simulating carbon sequestration and GHGs emissions in <Emphasis Type="Italic">Abies fabric</Emphasis> forest on the Gongga Mountains using a biogeochemical process model Forest-DNDC

The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs （greenhouse gases） fluxes （CO2, NO and N2O） in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga Mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production （GPP） of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production （NPP） was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production （NEP） was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively.     

Promotive effect of se on the growth and antioxidation of a blue-green algaSpirulina maxima

Cultures of a blue-green algaSpirulina maxima (Setch. et Gard.) Geitler with various concentrations of Se in Zarrouk's medium showed that not higher than 40 mg/L Se could promote its growth. The present experiments showed thatS. maxima grown under normal conditions, has an oxidant stress defence system for hydrogen peroxide (H₂O₂) removal, which is the Halliwell-Asada pathway. When 4 to 20 mg/L Se was added to the algal medium, this pathway was replaced by a so-called Sestressed pathway containing GSH peroxidase (GSH-POD). As a result of the occurrence of both higher activity of GSH-POD and lower levels of hydroxyl radical (OH·), the Se-stressed pathway scavenged H₂O₂ so effectively that the growth ofS. maxima was promoted by 4 to 20 mg/L Se. While GSH-POD activity of the alga disappeared at 40 mg/L Se, the recovery of ascorbate peroxidase was observed. The lower levels of ascorbic acid and GSH made the Halliwell-Asada pathway for scavenging H₂O₂ less effective, while the highest activity of catalase might be responsible in part for the H₂O₂ removal, causing the level of OH· inS. maxima grown at 40 mg/L Se to be much higher than the OH· level in this alga grown at 4 to 20 mg/L Se, but lower than that in the control. The OH· level changes caused the growth ofS. maxima cultured at 40 mg/L Se to increase slightly to close to that of the control.     

Immunosuppressive activities of fucoidan from Laminaria japonica

Effects of fucoidan fromLaminaria japonica on 2,4-dinitrochlorobenzene induced delayed-type hypersensitivity (DTH) reaction and the serum levels of IgG, IgM, complement C3 and C4 were investigated in the present study. Results showed that oral administration of fucoidan at dose of 150 and 300 mg/(kg· d) for 9 days before the hapten challenge significantly inhibited 2,4-dinitrochlorobenzene induced delayed-type hypersensitivity reaction; and also inhibited the humoral immunity. Serum C3 and C4 levels were markedly reduced by fucoidan at dose of 150 and 300 mg/kg; and serum IgG and IgM levels were reduced by fucoidan at dose of 300mg/kg. The inhibitory effects of fucoidan on delayed-type hypersensitivity suggested that it may be potential medication for chronic inflammatory diseases in the future. This study was supported by National Foundation for New Drug Research & Development (NFND) No.144.     

烟台近岸海域表层沉积物重金属污染特征

采取烟台近岸海域150个海底表层沉积物样品进行Hg,Cu,Pb,Zn,Cd,Cr,As,Ni元素分析。结果显示,烟台市近岸海域重金属主要富集在芝罘湾(Cd,Cu)、龙口(As,Cr,Cu)及海阳东部(Ni,Pb)一带,而莱州、招远及牟平近岸海域重金属含量较低。单因子、内梅罗和潜在生态危害指数评价结果显示,研究区88%海域的沉积物达到一类标准,轻污染区主要分布在芝罘岛北部及龙口市西部,龙口、招远及烟台市近岸沉积物潜在风险中等。     

Heavy metal concentration and its evaluation in the organisms from Meizhou Bay

The present paper reports Zn,Cu,Pb,Cd,Ni,Fe,Mn and Co contents in the tissues of oyster,solen,red-tail prawn,sea eel and kelp,taken from Meizhou Bay(and analysed by flame atomicabsorption spectrophotometry after wet digestion)in June 1992,and also the concentration factors esti-mated from the mean metal concentrations in the organisms and water there.Heavy metal concentrationsin every species of the organisms followed the pattern:Fe,Mn,Cu,Zn>Pb,Cd,Ni,Co and in variousorganisms showed considerable variation.In general,levels of most of these metals were in the order:softtissues of the bivalves>the kelp>muscles of the red-tail prawn,the sea eel.The greatest concentrationof most metals was found in the gill or viscera of the sea eel,whereas the muscle tissues,in general,con-tained only low concentrations of them.The Cu,Zn concentration factors of the oyster were higher by1—2 orders of magnitude than that of the other organisms.The observed heavy metal levels were closeto those reported from various waters     

NEW OBSERVATIONS ON THE MEIOTIC PROCESS IN THE MARINE DINOFLAGELLATE NOCTILUCA SCINTILIANS （NOCTILUCALES, DINOPHYCEAE）

The meiotic process in Noctiluca scintillans were observed under light microscope.Some abnormal cell divisions, incompletely separated “zoospores” and the changes of the zoospores are described in this paper. Together with the fmdings of field samplings and the previous results by other researchers, the process of meiosis in N. scintillans was supposed to be a pathway to reduce the extra high density of NH3-N within the cell in order to ensure normal population growth.