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1.
研究珠江口表层沉积物中重金属的污染现状,为珠江口海域的生态环境保护提供科学依据。2015年1月和4月对珠江口水域18个采样站位进行了2次取样调查,测定了表层沉积物中6种重金属(Cr、Cd、Cu、Pb、Zn、Ni)含量,采用污染指数法、地质累积指数法和潜在生态危害指数法对重金属污染水平及潜在生态风险进行了评价。结果显示,珠江口表层沉积物中Cr、Cd、Cu、Pb、Zn的平均含量分别为114.70、0.80、58.73、80.01、191.57 mg/kg,均高于国家标准(GB 18668-2002)第一类沉积物质量标准限值,但未超过第二类标准值;Ni的平均含量为51.89 mg/kg。6种重金属的含量变化趋势基本一致,由北向南逐渐降低,西部站位的含量高于东部站位。评价结果显示,本次研究区域的沉积物环境已经受到一定程度的污染,其中Cd是目前珠江口表层沉积物中污染较严重的重金属污染物。  相似文献   

2.
2003年5月、8月和10月对东山湾巴非蛤养殖区环境状况进行调查,根据调查资料,分析了巴非蛤养殖区海水、表层沉积物中Cu、Pb、Cd、Zn的含量分布,并进行生态环境质量评价及潜在生态危害评价.结果表明:东山湾巴非蛤养殖区海水中Cu、Pb、Cd、Zn的平均含量分别为1.75 μg.L-1,1.69 μg.L-1,0.02 μg.L-1,2.84 μg.L-1,其季节变化从高到低依次为10月＞8月＞5月;沉积物中Cu、Pb、Cd、Zn的平均含量分别为14.0 mg.kg-1、34.8 mg.kg-1、0.031 mg.kg-1、97.5 mg.kg-1.生态质量评价结果表明,养殖区海水重金属的含量符合第二类海水水质标准要求,处于清洁水平.养殖区沉积物重金属的含量符合第一类海洋沉积物质量标准,属于较清洁水平.生态危害评价表明,Pb和Cd的潜在生态危害系数大于Cu和Zn,但整个养殖区沉积物中重金属的潜在危害属于轻微,养殖环境良好.  相似文献   

3.
据2014年5月和8月福建安海湾9个站位的调查资料,分析海水、水中悬浮物和表层沉积物中Cu、Pb、Zn、Cd、Hg等5种重金属和类金属As的含量及分布特征,用单因子指数法、潜在生态危害评价法评价湾内重金属污染程度。结果表明,海水分布从湾顶往湾内和湾口逐渐降低,以湾顶值最高;水中悬浮物Cu、Pb、Zn、As、Hg含量以AH5站最高,Cd含量以AH6站最高,并向周边逐渐降低;表层沉积物含量从AH5站向湾内及湾口逐渐降低。部分站位海水和沉积物中Cu、Zn含量相对偏高,Pb、Cd、As、Hg含量均符合海水及沉积物质量标准的第一类要求。安海湾海域不同介质中悬浮物的含量最高,表层沉积物次之,海水的含量最低。水中悬浮物8月含量潜在生态危害程度远大于5月,以AH5站的潜在生态危害程度最强,主要潜在生态危害元素为Cd和Hg;表层沉积物以AH1、AH5站的潜在生态危害程度稍强,主要潜在生态危害元素为Cd,Hg次之。安海湾海域环境受到不同程度的重金属污染,陆源重金属污染物排放成为主要来源,本研究为安海湾海域生态环境防治提供科学依据。  相似文献   

4.
乳山湾沉积物重金属污染及其生态危害评价   总被引：22，自引：0，他引：22       下载免费PDF全文
根据2003年对乳山湾东湾表层沉积物中重金属调查结果，对重金属含量分布及富集特征进行分析，并采用瑞典科学家Hakanson提出的潜在生态危害指数法对其生态危害程度进行评价。结果表明，乳山湾沉积物中的重金属含量，除5月的Hg、As平均含量略低于8月外，其他重金属(Cu、Zn、Pb、Cd)平均含量5月高于8月。在表层沉积物中Cd的富集程度最大，除5月1号测站外，污染指数超过1．0。水平分布除Cd为湾口处含量较低外，其他重金属基本呈湾口和湾底含量较高的分布趋势。单个重金属潜在危害系数表明，Cd的E值大于其他重金属的E；值，其他重金属的E值均小于Hakanson所提出的沉积物重金属生态危害程度的轻微危害程度的划分标准，表明重金属对乳山湾生态环境具有潜在影响的元素主要是Cd，污染程度由高到低依次为Cd、Hg、As、Pb、Cu、Zn。与历史同期调查相比，表层沉积物中Cd含量升高幅度最大。从多个重金属的潜在生态危害指数看，两次RI调查均值小于150，属于轻微的生态危害。  相似文献   

5.
阿哈水库是贵阳市重要的饮用水源地,及时掌握其沉积物中重金属的污染现状和存在的潜在生态风险具有非常重要的现实意义。本文对阿哈水库库区4个采样点的柱状沉积物中重金属铜(Cu)、锌(Zn)、镉(Cd)、铅(Pb)、铬(Cr)、镍(Ni)6种毒性重金属进行了检测分析。结果表明,6种重金属含量在空间分布上有显著差异。在水平方向上,库心沉积物中的Cu、Cr和Pb含量最高,南郊水厂取水口的Zn和Cd含量最高,金钟河和游鱼河入库口沉积物中的6种重金属含量都相对较低。垂直方向上,南郊水厂取水口和库中心这两个采样点中Cr、Pb、Cu、Ni、Zn、Cd6种重金属峰值均出现在10-15 cm处。Zn、Cu和Pb平均含量都超过背景值,Cd富集系数最高,污染最严重。同时,潜在生态风险评价结果显示,水库沉积物重金属潜在生态危害风险从大到小依次为Cd,Cu,Pb,Ni,Zn,Cr,Cd是生态风险贡献因子,阿哈水库沉积物重金属总体上还是存在轻微的生态危害风险及处于轻微的污染状态。  相似文献   

6.
研究阿哈水库沉积物中重金属空间分布特征和污染现状,评价潜在生态风险,为重金属污染防治提供参考依据和理论基础。2016年12月,在阿哈水库设置4个采样点,每个采样点采集20cm柱状沉积物,按5cm分层取样,检测分析铜(Cu)、锌(Zn)、镉(Cd)、铅(Pb)、铬(Cr)、镍(Ni)6种毒性重金属,用潜在生态危害指数法评价生态风险。结果表明,6种重金属含量在空间分布上有显著差异。水平方向,沉积物中Cu、Cr和Pb含量库心最高,Zn和Cd含量南郊水厂取水口最高,沉积物中的6种重金属含量在金钟河和游鱼河入库口都相对较低。垂直方向上,南郊水厂取水口和库心采样点Cr、Pb、Cu、Ni、Zn、Cd 6种重金属峰值均出现在10~15cm处。Zn、Cu和Pb平均含量都超过背景值,Cd富集系数最高,污染最严重。潜在生态风险评价结果显示,水库沉积物重金属潜在生态危害指数从大到小依次为Cd、Cu、Pb、Ni、Zn、Cr,Cd是生态风险主要贡献因子。阿哈水库沉积物重金属总体上存在轻微的生态风险及处于轻微的污染状态,南郊水厂取水口较高的生态风险应当引起足够的重视。  相似文献   

7.
通过2017—2019年3年每年5月对江苏省启东市文蛤(Meretrix meretrix)养殖区表层海水和沉积物中重金属Cu、Zn、Pb、Cd的调查分析,采用概率生态风险评估法(probabilistic ecological risk assessment, PERA)评价了水体中重金属的生态风险,采用沉积物质量基准法(sediment quality guideline, SQG)评估了沉积物中重金属的潜在生物毒性。重金属生态风险评价结果表明,短期暴露下,4种重金属的安全阈值(MOS10)均大于1,Cu、Zn、Pb、Cd的浓度对10%水生生物产生毒性影响的水体比例分别为50.05%、25.38%、24.01%、19.09%,说明水体中4种重金属对水生生物短期潜在生态风险较小,对水生生物的生态风险大小依次为Cu>Zn>Pb>Cd。文蛤养殖海域表层沉积物中各金属元素的含量及分布较均匀,各站位差异较小。沉积物重金属污染潜在生物毒性评价结果显示,各站位沉积物均无Cd潜在生物毒性效应,部分站位沉积物偶有Cu、Pb、Zn的潜在生物毒性效应,其中发生Zn...  相似文献   

8.
为了解渤海中部海域沉积物中重金属的污染状况,于2013年8月采集了渤海中部海域34个站点的表层沉积物,检测了Pb、Cd、Hg、Cu、Zn和As 6种重金属的含量,分析了Pb、Cd、Cu和Zn 4种重金属的空间分布特征,采用污染指数法和潜在生态风险评价法对其表层沉积物重金属污染状况进行评价。结果显示,渤海中部海域表层沉积物重金属含量较低,符合海洋沉积物质量(GB 18668-2002)Ⅰ类标准的要求。表层沉积物重金属的空间分布总体呈现由近岸向中心海域降低的趋势。Cu、Zn和Pb含量空间变化趋势比较明显,靠近渤海湾海域重金属含量高,离岸距离越远,重金属含量逐渐降低。Cd含量在靠近黄河入海海域最高,呈现自高值区向东西两边海域减小的趋势。各个站位的重金属单因子污染程度较轻,单因子污染系数均值大小顺序为PbCuZnAsCdHg;重金属综合污染指数都小于5,表现为低污染水平。除1号站位的Hg单因子潜在生态风险系数为54.44之外,其他站位表层沉积物Hg、As、Cu、Zn、Pb和Cd的单因子潜在生态风险系数Eir小于40,范围为0.39～38.80,风险程度由高到低依次为Hg、Cd、As、Pb、Cu和Zn;其综合潜在生态风险系数小于150,范围为16.39～79.57。其中,1号站位综合潜在生态风险系数最高达到79.57。研究表明,此海域属于低潜在生态风险水平,风险指数高值区出现在唐山大清河口海域。  相似文献   

9.
2008年珠江口表层沉积物重金属含量及生态危害评价   总被引：1，自引：0，他引：1  
2008年5、8月针对珠江口表层沉积物重金属的空间分布、相关性、超标倍数和超标率等进行了研究,并采用综合污染指数法和Hakanson潜在生态危害指数法对其污染特征和生态危害进行了评价。结果显示:研究期间珠江口表层沉积物中重金属Cu为63.2 mg/kg、Zn为261.0 mg/kg、Pb为96.7 mg/kg、Cd为6.7 mg/kg、Cr为167.4 mg/kg。同一口门5种重金属相关极显著(P<0.01);每种重金属含量在各口门间相关极显著,表明其具有较强的同源性。珠江口水域重金含量表现出整体的超标现象,超标率均不低于87.5%,Cd超标倍数最大。综合污染指数法评价显示,重金属污染处重度水平,潜在生态危害指数法显示,重金属潜在生态危害处于较严重水平;Cd对污染和潜在生态危害贡献率最大。  相似文献   

10.
根据2012年3月、5月、8月、11月表层沉积物调查资料,分析了双岛湾附近人工鱼礁区表层沉积物重金属的分布特征,采用潜在生态风险评价法对重金属的生态危害进行了评价。结果表明:(1)研究海域表层沉积物中重金属含量较低,全部测站Cu、Zn、Pb、Cd、Hg、As的含量符合《海洋沉积物质量》(GB 18668-2002)Ⅰ类标准;(2)表层沉积物中重金属的分布较为规律,除Hg含量站间差异不明显外,鱼礁区内站点的Cu、Zn、Pb、Cd、As重金属含量低于周边海域;(3)表层沉积物中重金属含量的月际变化比较明显,以8月最高、3月最低;(4)双岛湾附近海域重金属污染程度为低级,且总体潜在生态危害属轻微水平。  相似文献   

11.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

12.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

13.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

14.
There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.  相似文献   

15.
This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.  相似文献   

16.
The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 103 to 3.76 × 105 cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 105 cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

17.
The sea raven, Hemitripterus americanus, is a sit-and-wait, low metabolic rate, marine teleost. The objective of this study was to determine i) whether cortisol implantation (50 mg. kg-1) for 7 days altered hepatocyte metabolism, and hepatocyte responsiveness to epinephrine, glucagon and insulin, and ii) whether 8 weeks of food-deprivation modified the above response. Cortisol implantation significantly increased hepatocyte total glucose production and oxidation from alanine compared to the sham group. There was no cortisol effect on glycogen breakdown, suggesting that the activation of other pathways, including gluconeogenesis, are required to account for the increased glucose production. Epinephrine-mediated (10-5M) glycogen breakdown and insulin-mediated (10-8M) total glucose production were enhanced in hepatocytes of cortisol implanted sea ravens, but there were no change in any glucagon (10-7M) effects. The enhanced glycogen breakdown in the absence of similar increases in total glucose production with epinephrine indicates mobilization of carbohydrate reserves for endogenous use by the liver. Food-deprivation for 8 weeks significantly decreased condition factor, plasma cortisol concentration and liver glycogen content in the sea raven, but had no effect on plasma glucose concentration. Hepatocyte total glucose production and flux rates from alanine increased significantly with food-deprivation. Moreover, food-deprivation increased responsiveness of total hepatocyte glucose production to the actions of glucagon and insulin, but not to epinephrine; none of these effects were modified by cortisol implantation. Our results indicate that cortisol in the sea raven exerts both a direct and an indirect or permissive effect on hepatocyte metabolism by modifying hepatocyte responsiveness to epinephrine and insulin stimulation. Cortisol implantation did not modify the effects of glucagon or food-deprivation in this species.  相似文献   

18.
Important environmental processes for the survival and recruitment of early life stages of pelagic fishes have been synthesized through Bakun's fundamental triad as enrichment, concentration and retention processes (A. Bakun, 1996, Patterns in the Ocean. Ocean Processes and Marine Population Dynamics. San Diego, CA, USA: University of California Sea Grant). This conceptual framework states that from favourable spawning habitats, eggs and larvae would be transported to and/or retained in places where food originating from enrichment areas would be concentrated. We propose a method for quantifying two of the triad processes, enrichment and retention, based on the Lagrangian tracking of particles transported within water velocity fields generated by a three‐dimensional hydrodynamic model. We apply this method to the southern Benguela upwelling ecosystem, constructing putative maps of enrichment and retention. We comment on these maps regarding main features of the circulation in the region, and investigate seasonal variability of the processes. We finally discuss the results in relation to available knowledge on the reproductive strategies of two pelagic clupeoid species abundant in the southern Benguela, anchovy (Engraulis encrasicolus) and sardine (Sardinops sagax). Our approach is intended to be sufficiently generic so as to allow its application to other upwelling systems.  相似文献   

19.
This study evaluated the effects of three levels of loading density (200, 300 and 400 g L−1) and four levels of duration (1, 3, 6 and 9 h) on the mortality, plasma cortisol and chloride levels and growth of rohu Labeo rohita fingerlings in a transport simulation. While total immediate mortality was low (4–12%), delayed mortality was high (27–49%). Initial capture and handling were found to constitute the most stressful phase as indicated by elevated plasma cortisol. The levels of cortisol continued to rise at 6 and 9 h after transport, with the highest level observed at 9 h after transport. The level of plasma chloride fell after transport across all density levels and treatment durations. Specific growth rate (SGR, %/day) and total bacterial density (cfu/g) were not different between and within treatments, and between treatments and the controls. This study demonstrates that transport has a profound effect on the stress responses of rohu fingerlings. Although the level of immediate mortality was low, the higher level of delayed mortality has serious implications in terms of production inefficiency for grow-out farmers.  相似文献   

20.
  • 1. The common name ‘tilapia’ refers to a group of tropical freshwater fish in the family Cichlidae (Oreochromis, Tilapia, and Sarotherodon spp.) that are indigenous to Africa and the southwestern Middle East. Since the 1930s, tilapias have been intentionally dispersed worldwide for the biological control of aquatic weeds and insects, as baitfish for certain capture fisheries, for aquaria, and as a food fish. They have most recently been promoted as an important source of protein that could provide food security for developing countries without the environmental problems associated with terrestrial agriculture. In addition, market demand for tilapia in developed countries such as the United States is growing rapidly.
  • 2. Tilapias are well‐suited to aquaculture because they are highly prolific and tolerant to a range of environmental conditions. They have come to be known as the ‘aquatic chicken’ because of their potential as an affordable, high‐yield source of protein that can be easily raised in a range of environments — from subsistence or ‘backyard’ units to intensive fish hatcheries. In some countries, particularly in Asia, nearly all of the introduced tilapias produced are consumed domestically; tilapias have contributed to basic food security for such societies.
  • 3. This review indicates that tilapia species are highly invasive and exist under feral conditions in every nation in which they have been cultured or introduced. Thus, the authors have concluded that, despite potential or observed benefits to human society, tilapia aquaculture and open‐water introductions cannot continue unchecked without further exacerbating damage to native fish species and biodiversity. Recommendations include restricting tilapia culture to carefully managed, contained ponds, although exclusion is preferred when it is feasible. Research into culture of indigenous species is also recommended.
Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

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