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1.
Radon concentration was measured in water samples of 41 different locations from Udhampur district of Jammu & Kashmir, India, by using RAD7 and Smart RnDuo monitor. The variation of radon concentration in water ranged from 1.44 ± 0.31 to 63.64 ± 2.88 Bq L?1, with a mean value of 28.73 Bq L?1 using RAD7 and 0.64 ± 0.28 to 52.65 ± 2.50 Bq L?1, with a mean value of 20.30 Bq L?1 using Smart RnDuo monitor, respectively. About 17.07% of the studied water samples recorded to display elevated radon concentration above the reference range suggested by United Nation Scientific Committee on the Effects of Atomic Radiations (UNSCEAR). The mean annual effective dose of these samples was determined, and 78.95% samples were found to be within the safe limits set by World Health Organisation (WHO) and European Council (EU). The study revealed good agreement between the values obtained with two methods. Heavy metals (Zn, Cd, Fe, Cu, Ni, As, Hg, Co, Pb and Cr) were determined in water samples by microwave plasma atomic emission spectrometer, and their correlation with radon content was also analysed.  相似文献   

2.
The increase in intensive aquaculture production in the Bolinao Bay, Philippines reached the point of harmful influence to production stock. Up to the present, there has been no estimation of aquaculture carrying capacity which is based on quantification of processes responsible for (a) water quality inside the units, (b) impact to the seabed and (c) water quality in the whole Bolinao Bay. The numerical estimation of tidal circulation, which is the most dominant part of the hydrodynamical regime in the Bolinao Bay, represents an unavoidable step in the carrying capacity determination considering points (a), (b) and (c). The hydrodynamical model we apply is a free surface, 3D finite element tidal model, forced with sea elevation dynamics at three open boundaries. It incorporates an increase in bottom stress drag coefficients in the coral areas and advanced transport corrected advection scheme. The model simulations of water flow show good agreement with measured currents in the central part of the Bolinao Bay, southern and northeastern channel, while agreement in the areas in vicinity of northern channel is not as tight. In order to provide an insight into the water exchange in aquaculture units, to support local water quality models and seabed deposition models (points (a) and (b)), the area is mapped with neap tide mean, spring tide mean and 14-day mean current velocity contours. The highest 14-day mean velocities are attained in the southern channel (>17 cm s−1), while the mean velocities characteristic for northern part (<6 cm s−1) and shallow areas of coral reefs (<2 cm s−1) are much lower. Area-mean difference between spring tide and 14-day mean velocities is estimated to be 18.32% (std=7.31%), while difference between neap tide and 14-day mean velocities is 17.62 % (std=11.19%). To support global basin-wide water quality models (point (c)), retention of water in the bay is estimated by Lagrangian and Eulerian calculation procedure of mean residence time field. Both calculations estimate the highest (no-wind) residence times (Lan: 25.4 days, Eul: 21.03 days) in the central northern part, but most of the area (Lan: 73.11%, Eul: 79.31%) is characterized by residence time values significantly lower than 15 days. The results are readily applicable for upcoming implementation in the models of local (aquaculture units, seabed) and basin-wide (Bolinao Bay) nutrient dynamics, primary and secondary production, organic matter decomposition and oxygen dynamics.  相似文献   

3.
Concentrations and distributions of selected fluoroquinolones (norfloxacin, ciprofloxacin and enrofloxacin) in water, sediments and nine kinds of fish species collected from 6 sites in two marine aquaculture regions of the Pearl River Delta, China, were analyzed by using high-performance liquid chromatography with fluorescence detector (HPLC). The results showed that the concentrations of ciprofloxacin and enrofloxacin were below the limits of quantification (LOQ) in all water samples except for norfloxacin. Norfloxacin and ciprofloxacin concentrations ranged from 1.88 to 11.20 ng g−1 dry wt, 0.76–2.42 ng g−1 dry wt in sediments collected from the Dapeng’ao region (sites 1–3) and ranged from 2.31 to 4.75 ng g−1 dry wt, 1.26–1.76 ng g−1 dry wt in sediments collected from the Hailing Island region (sites 4–6), respectively. However, no enrofloxacin was found in all sediment samples. The three fluoroquinolones (FQs) were detected in all fish samples, and the concentrations were higher in liver tissues than those in muscle tissues. The levels of norfloxacin were higher than ciprofloxacin and enrofloxacin in both liver and muscle tissues. Among the nine marine fish species, Siganus fuscescens from Hailing Island had a significantly high level of norfloxacin in liver tissue (254.58 ng g−1 wet wt), followed by Sparus macrocephalus (133.15 ng g−1 wet wt) from Dapeng’ao, and the lowest value was Lutianus argentimaculatus (5.18 ng g−1 wet wt) from Hailing Island. The obtained results of FQs in present study do not represent a risk to the human health in Guangdong coastal area, based on the maximum residue limits (MRLs) established by Chinese Government and the acceptable daily intake (ADI) recommended by the Food and Agriculture Organization and World Health Organization (FAO/WHO).  相似文献   

4.
The occurrence of chitinase in the stomach contents of Enophrys bison and Platichthys stellatus was investigated. The highest chitinase activity and the greatest percentage of chitinoclastic bacteria in relation to the total bacterial flora were associated with fish whose stomach content was composed primarily of chitinous animals. Stomach contents lacking visible chitin possessed low or no detectable levels of chitinase activity and few chitinoclastic bacteria. Juvenile E. bison treated with chloramphenicol to remove their indigenous bacterial flora had no detectable level of chitinase in their stomach contents while non-treated juveniles showed inducible chitinase activity, indicating the bacterial origin for the chitinase.Published as Technical Paper No. 4435, Oregon Agricultural Experiment Station. This research was supported by NIH training grant 5TO1 GM-00704 and NSF grant DES73-06611 AO2.  相似文献   

5.
The development of marine fouling communities was followed as part of a sewage abatement study in Kaneohe Bay (Oahu, Hawaii). Panels immersed near the outfall during sewage discharge were dominated by dense mats of blue-green algae and diatoms. This mat was significantly lighter at this station when sewage did not flow into the bay, and it never developed on panels within the same sector of the bay but away from the influence of the outfall. Taxonomic diversity, and the frequency of filamentous algae and the serpulidHydroides elegans were reduced near the outfall during discharge. It is suggested that this reduction in diversity and abundance of certain key foulers is due to competitive exclusion by the dense blue-green and diatom mats, and is not a direct effect of the sewage effluent.  相似文献   

6.
In the context of use of marine algae as biological indicators of heavy metal pollution in coastal waters, six species of marine algae collected from the southwest coast of India were analysed for the levels of heavy metals (Ni, Cr, Sr, and Ag). Interspecies and interclass variations were determined on a spatial and temporal scale. The metal contents varied in the ranges, Ni: 0.20–21.06?µg?g?1 (mean?=?10.13?µg?g?1), Cr: non-detectable level (ND)–37.18?µg?g?1 (mean?=?13.86?µg?g?1), Sr: 2.19–103.90?µg?g?1 (mean =?29.40?µg?g?1), and Ag: ND–6.39?µg?g?1 (mean?=?1.80?µg?g?1). Ni and Cr contents were of similar magnitude to those reported for algae from polluted areas.  相似文献   

7.
It is proposed that unstructured food webs may more closely resemble real marine food webs than does the conventional, structured model. An unstructured food-web model leads to a set of very simple expressions for the potential partition of matter in the food web in steady state, including the potential fluxes of material and biomasses of trophic types and the concentration of trace substances in the members and materials of such a food web. The approach may explain some anomalies of relative predator-prey biomasses and of trace-element distribution, and may be of further use for analyzing and predicting (a) the tropho-dynamic parameters of marine systems, (b) the trophic positions, and the steadystate fluxes and biomasses of marine organisms, (c) the distribution of trace materials in marine biota; and for relating findings among these areas. Other matters, such as limitations of food conversion, indicated by concentration factors of trace substances, the possibilities of non-causal association of anomalously high levels of trace substances (including pollutants) with diseased or otherwise abnormal marine creatures, and an inverse relationship of early concentrations of newly introduced trace substances and their eventual concentrations in various organisms, are also developed in this approach.  相似文献   

8.
格林威治湾是纳拉甘西特湾一处受到多种影响因子作用的城市化形成港湾。本研究鉴定了对于格林威治湾底栖动物的重要影响因素。首先利用现存数据与信息来验证水体受损情况。其次确定了影响来源,影响因素和具体影响的存在。继而探究了来源,影响因素和具体影响之间的关系。这使我们能够鉴定出最可能危害水体的影响因素。本研究评估了化学制品、营养物质和悬浮沉积物3类污染物。这种证据权重的方法表明格林威治湾主要受到富营养化相关的影响因素危害。格林威治湾的沉积物富含碳,低溶解氧浓度的情况十分常见,尤其在格林威治湾西部。底栖生物群落出现发育不良的情况,与在氧气不足情况下的预测结果吻合。尽管我们的分析表明环境中的污染物浓度可能导致有害结果的出现,我们并未在结果中检出毒性。这是由于沉积物中存在大量的有机物,这些有机物限制了污染物的生物可利用性。我们的分析还表明悬浮沉积物的影响对于湾区的大部分区域而言几乎不存在。本分析展示了诊断法步骤可以用于组织和评估影响格林威治湾生态健康的潜在影响因素。诊断法步骤对于管理受到多重因素影响的水体非常有用。
精选自Marguerite Pelletier, Kay Ho, Mark Cantwell, Monique Perron, Kenneth Rocha, Robert M. Burgess, Roxanne Johnson, Kenneth Perez, John Cardin, Michael A. Charpentier. Diagnosis of potential stressors adversely affecting benthic invertebrate communities in Greenwich Bay, Rhode Island, USA. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 449–462, July 2017. DOI: 10.1002/etc.3562
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3562/full
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9.
Like female dog whelks (Nucella lapillus) in the Atlantic Ocean, females of the Pacific gastropod N. lima respond to low concentrations of tri-n-butyltin (TBT) by growing a penis and vas deferens. This condition, termed imposex, was found to occur in N. lima collected from August 1987 to May 1988 along a TBT pollution gradient associated with a marina in Auke Bay, Alaska. The suite of symptoms characteristic of imposex in N. lima was slightly different than in N. lapillus. Imposex, as measured by relative penis size (RPS) of females to males, increased from 0.0 to 34.27 along this gradient and as measured by vas deferens sequenceindex (VDS) increased similarly from 0.0 to 4.29. Concentrations of TBT in N. lima increased from below detection limits (about 0.010 g Sn g-1 dry tissue wt) to 0.065 g Sn g-1 dry tissue wt along the gradient. The gradient was determined by measuring TBT in whole-body tissues of bay mussels (Mytilus edulis). Concentrations of TBT in mussels increased from below detection limits to 0.833 g Sn g-1 dry tissue wt in mussels from within the marina that was the major local source of TBT. Imposex, tissue TBT burden, and position along a TBT pollution gradient are significantly correlated (P<0.01) in N. lima. TBT was tested as a causative agent for imposex by exposing snails at a distant control site to TBT paint. After 1 mo exposure, 33% of the females grew a penis ranging in size from 0.2 to 0.8 mm. Our results generally corroborate those found for N. lapillus and indicate that imposex in N. lima is caused by environmental TBT exposure. We suggest that the RPS in the genus Nucella may be useful in monitoring TBT in coastal waters worldwide.  相似文献   

10.
The role of birds in intertidal food webs is mediated by effects of tides on the habitat, distribution, and accessibility of food organisms. We studied effects of elevation, sediment characteristics, vegetation, and tidal cycles on waterfowl feeding and food organisms in Boundary Bay, British Columbia, Canada from September to March 1990–1992. Percent dry mass of esophageal contents was mainly Zostera japonica leaves (84%) for American wigeon (Anas americana Gmelin), and leaves of Z. japonica (57%) and Z. marina (41%) for brant (Branta bernicla L.). Northern pintails (A. acuta L.) and mallards (A. platyrhynchos L.) ate mostly the leaves, seeds, and rhizomes of Z. japonica (48 and 72%, respectively) and gastropods (12 and 28%). Green-winged teal (A. crecca L.) ate mainly amphipods (68%) and saltmarsh seeds (19%). The well-sorted fine sand (median 0.125 mm) to medium sand (0.25 mm), and the low organic carbon content (1.31±0.12% dry mass), did not appear to vary sufficiently along 2.1- and 2.6-km transects to affect macroinvertebrate distributions. Three habitat zones were recognized: (1) upper intertidal (sandflats); (2) mid-intertidal (largely monotypic Z. japonica); and (3) lower intertidal (mixed Z. japonica and Z. marina). These zones, although related to elevation, had greater influence on amphipod distributions than did elevation alone or detrital biomass. Biomass and numbers of most invertebrate foods of waterfowl were greatest in the eelgrass zones, with the upper elevational limit of Z. japonica occurring at about Mean Water Level (MWL). Accordingly, wigeon, pintails, and mallards fed mostly below MWL. Because of seasonal tidal cycles, daily accessibility of areas below MWL but within reach of surfacefeeding waterfowl decreased from a mean of 10.8 h in October to 9.6 h in December. In October only 10 d and <12 h available feeding time, whereas in December and January every day had <12 h available feeding time. Seasonal effects of tides on accessibility might limit sufficient feeding by some waterfowl species in intertidal areas, increasing their reliance on alternative feeding sites.  相似文献   

11.
Oxidation of polycyclic aromatic hydrocarbons (PAH) and epoxide-conjugation capacities were examined from mussels, Mytilus galloprovincialis, collected from a clean site at the entrance to Arcachon Bay (south-west France) in 1984, using subcellular preparations from whole bodies and digestive glands. The existence of low-cytochrome P-450-dependent oxygenase activities [cytochrome P-450 content, NADPH cytochrome c reductase and benzopyrene monooxygenase (BaPMO) activities] was confirmed, as well as the presence of a comparatively important capacity for epoxide conjugation [epoxide hydrolase (EH), glutathione S epoxide-transferase (GST) activities and total cytosolic-glutathione content]. The optimal incubation temperatures for the individual in vitro enzyme activities in the mussel (25°C for BaPMO, 31°C for EH and GST) were lower than that required for optimal mammalian enzyme activities. Except for cytochrome P-450 content, there was no significant difference in enzyme activities recorded in whole-body and digestive gland fractions.  相似文献   

12.
13.
This article uses vector autoregressions (VARs) and a dynamic linear rational expectations model to analyze the effects of sea surface temperatures and catch prices on fishing effort for albacore tuna, Chinook salmon, sablefish, and squid in Monterey Bay, California. The VAR results show that fluctuations in sea surface temperatures, including El Niño events, have significant effects on effort and prices for these fisheries. Estimation of the model shows that El Niño has positive effects on the abundance in Monterey Bay of albacore and negative effects on Chinook, sablefish, and squid. Testing of the model supports rational expectations by harvesters of albacore, Chinook, and sablefish but not squid. Test results also suggest that dynamic adjustment costs are not significant for albacore, Chinook, or sablefish fisheries.  相似文献   

14.
象山港沉积物与生物体中多氯联苯分布特征与暴露风险   总被引:2,自引:0,他引:2  
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15.
为了解大亚湾常见野生海产品中重金属的含量及其摄食的健康风险,本文分析了大亚湾10种野生海产品可食用部分中7种重金属(As、Cd、Cr、Cu、Pb、Ni、Zn)含量,并采用单因子污染指数(P_i)、综合污染指数(P_c)方法评价其污染程度,进一步采用美国环保署推荐的健康风险评估模型评估其摄食的健康风险.结果表明,7种重金属含量分别为4.28×10~(-2)—1.31×10~(-1)、8.58×10~(-5)—2.19×10~(-2)、2.69×10~(-3)—9.54×10~(-3)、1.92×10~(-2)—3.05×10~(-1)、ND—2.14×10~(-2)、8.40×10~(-4)—2.75×10~(-1)、1.92×10~(-1)—6.13×10~(-1) mg·kg~(-1)(湿重).与国内外其它地区相比,处于相对较低水平;与历史数据相比,呈现降低趋势.P_i及P_c结果表明,金钱鱼、平鲷、口虾蛄和棒锥螺中As处于轻度污染水平,其余重金属均处于无污染水平.风险评估结果表明,大亚湾海产品可食用部分中总砷的摄食致癌风险较高,儿童/青少年的致癌风险高于成人1.5倍.金钱鱼、口虾蛄、杜氏枪乌贼、近缘新对虾、蟹和棒锥螺的日均消费量(成人57.4 g·d~(-1),儿童/青少年42.4 g·d~(-1))均高于消费建议中给出的相应安全阈值,建议消费者适当控制这些海产品的日食用量和月食用餐数.As在海产品中较高的检出,需予以进一步关注.  相似文献   

16.
G. Schneider 《Marine Biology》1989,100(4):507-514
The population dynamics, ammonia and inorganic phosphate excretion, and nutrient regeneration of the common jellyfish Aurelia aurita was investigated from 1982 to 1984 in the Kiel Bight, western Baltic Sea. During summer 1982, medusae abundance ranged between 14 and 23 individuals 100 m-3, biomass was estimated at about 5 g C 100 m-3 and the mean final diameter of individuals was 22 cm. Abundance, based on numbers, in 1983 and 1984 was an order of magnitude lower; biomass was less than 2 g C 100 m-3 and jellyfish grew to 30 cm. During the summers of 1983 and 1984, A. aurita biomass constituted roughly 40% of that of the total zooplankton>200 m. In 1982, for which zooplankton data were lacking, it was assumed that medusae biomass was greater than that of all other zooplankton groups. Total ammonia excretion ranged between 6.5 and 36 mol h-1 individual-1, whereas inorganic phosphate release was 1.4 to 5.7 mol h-1 individual-1. Allometric equations were calculated and exponents of 0.93 for NH4–N release and 0.87 for PO4–P excretion were determined. Nitrogen and phosphorus turnover rates were 5.4 and 14.6% d-1, respectively. In 1982, the medusae population released 1 100 mol NH4–N m-2 d-1, about 11% of the nitrogen requirements of the phytoplankton. The inorganic phosphate excretion (150 mol m-2 d-1) sustained 23% of the nutrient demands of the primary producers. In the other two years the nutrient cycling of the medusae was much less important, and satisfied only 3 to 6% of the nutrient demands. It is suggested that in some years A. aurita is the second most important source of regenerated nutrients in Kiel Bight, next to sediment.  相似文献   

17.
This research deals with the sulfurous spring waters flow along the course of the Euphrates River in western Iraq in the area extended between Haqlaniya and Hit within the Al-Anbar governorate. Eleven springs (3 in Haqlanya, 4 in Kubaysa and 4 in Hit) have been addressed for the purpose of water evaluation for balneology, drinking, irrigation and aquaculture (fish farming). In order to meet the objectives of this research, all springs were sampled and analyzed for the total dissolved solid, electrical conductivity, pH, temperature, major cations (Ca2+, Mg2+, Na+ and K+), major anions (SO4 2?, Cl?, HCO3 ? and CO3 2?), minor anions (PO4 3?and NO3 ?) as well as the trace elements that included Pb, Zn, Cd, Ni, Fe, Mn, Cu, Br, F, Ba, B, Sr, Al, As, Cr, Hg and Se. The International Standards of World Health Organization are used for assessing the water quality. The results revealed that the springs belong to the tepid springs of 27–30 °C and classified as hypothermal to the thermal springs. Lithochemistry and geochemical processes clearly affected the water chemistry. The hydrogeochemical processes are responsible for the element enrichment in water by the chemical dissolution of carbonate and gypsum and evaporation as well. The results of the study indicate the possibility of using spring water for therapeutic purposes, but not allowed for drinking and aquaculture (fish farming), except those free of H2S gas. On the other hand, it can be used for irrigation with risk. However, soil type as well as proper selection of plants should be taken into consideration.  相似文献   

18.
The male of Laimella longicauda Cobb, 1920 is described as having short arcuate spicules and a gubernaculum with caudally directed apophyses. The genus Paracomesoma Schuurmans Stekhoven, 1950 is reinstated to accommodate species of Laimella sensu Chitwood, 1937. Paramesonchium n. gen. is proposed to accommodate Laimella (?) serialis Wieser, 1954. Actarjania n. gen. (type species A. splendens n. sp.) differs from Sabatieria in having irregular lateral rows of longitudinal punctations and short arcuate spicules with distinctive distal extremities.  相似文献   

19.
This paper describes a carbon budget for the spring phytoplankton bloom in Auke Bay, a subarctic bay in southeastern Alaska. The budget was constructed using semiweekly data on carbon production, particulate carbon in the water column, and cumulative sedimentation of carbon, chlorophyll a, and pheopigments. From these measured parameters, seasonal carbon consumption, utilization, and import/export terms were derived. The chlorophyll and pheopigment data were used to partition carbon sinking out of the photic zone between phytoplankton cells and fecal material. The difference between total carbon production and carbon available for consumption was attributed primarily to carbon import/export related to advection of water masses into and out of the bay. Separate budgets were developed for each of five sampling years (1985–1989). An average of 130±16 g C/m2 were produced by phytoplankton during each spring. Our model suggests that an average of 70% of this carbon was available for consumption by grazers within the bay; the remaining 30% is assumed to have been exported from the bay by advective transport. Of the available (non-exported) carbon, an average of 55% was consumed by grazers, 34% sank out of the photic zone in the form of uneaten algae, and about 11% remained at the end of the sampling period in the form of phytoplankton standing stocks. Overall, about 27% of the carbon produced each spring in Auke Bay (35 gC/m2) was used for growth and respiration by first-order consumers within the bay.  相似文献   

20.
A new genus, Meyersia, and five new species of the nematode family Oncholaimidae, are described from Biscayne Bay, Florida, and environs, viz., Metoncholaimus pelor n. sp., M. amplus n. sp., Meyersia major n. gen., n. sp., M. minor n. sp., and Filoncholaimus prolatus n. sp. Also included in the genus Meyersia are Adoncholaimus bandaenis Kreis, 1932 and A. meridionalis Kreis, 1932.  相似文献   

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