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541.
Evacuation mapping: the utility of guidelines 总被引:2,自引:0,他引:2
542.
Gunster DG Gillis CA Bonnevie NL Abel TB Wenning RJ 《Environmental pollution (Barking, Essex : 1987)》1993,82(3):245-253
Newark Bay, New Jersey, is particularly vulnerable to ecological damage from petroleum and chemical spills, as a result of the enclosed nature and shallow depth of the bay, the high frequency of shipping traffic, and the numerous chemical and petroleum transfer terminals located alongs its shores. To evaluate the potential impacts to the natural resources of this coastal estuarine ecosystem, chemical and petroleum accidents reported to the US Coast Guard (USCG) between 1982 and 1991 were compiled to determine the frequency and volume of these incidents in Newark Bay and in each of its major tributaries. Records obtained from the USCG National Response Center's computerized database indicated that more than 1453 accidental incidents, resulting in the release of more than 18 million US gallons of hazardous materials and petroleum products, occurred throughout Newark Bay during this period of time. The bulk of the materials released to the aquatic environment consisted of petroleum products, specifically No. 6 Fuel Oil (103 spills, 12 829 272 US gal) and gasoline (207 spills, 48 816 US gal). The majority of the reported incidents occurred in the Arthur Kill and its tributaries, as well as in the Kill Van Kull and the Passaic River. The results of this study indicated that the accidental discharge of petroleum and hazardous chemicals represents a significant source of chemical pollution in Newark Bay. Based on the frequency of spills and the volume of materials released to the aquatic environment, it is likely that these events are having a deleterious effect on the Newark Bay ecosystem. 相似文献
543.
Exposure of the temperate sea anemone Anemonia viridis Forskål to increased seawater temperature (from 16 to 26°C) reduced the lysosomal latency of coelenterate tissues. Lysosomes in the mesenterial filaments of anemones were destabilised by increased temperature, with greater destabilisation in heat-shocked symbiotic anemones than in heat-shocked aposymbiotic anemones in the early stages of the experiment. Lysosomal enzyme activity in zooxanthellae from heat-shocked symbiotic anemones was associated with the algal membranes and the cytoplasm of degenerate algal cells. While the relationship between host coelenterate and symbiotic alga may confer many benefits under normal conditions, comparison of the responses of symbiotic and aposymbiotic anemones to heat shock suggests that there may be disadvantages for symbiotic anemones under stress. 相似文献
544.
The accumulation of parasites in a fish host is modelled as a function of the total amount of prey consumed. The accumulated parasite load is then expressed as a function of fish length so that the asymptotic growth, L
, of any population of commonly infected fish can be estimated. Estimates of L
are obtained for orange roughy (Hoplostethus atlanticus), albacore tuna (Thunnus alalunga) and the New Zealand southern arrow squid (Nototodarus sloanii). 相似文献
545.
Prey selection by larval weakfish (Cynoscion regalis): the effects of prey size,speed, and abundance
We examined feeding by larval weakfish, Cynoscion regalis (Bloch and Schneider), in laboratory experiments conducted during the 1991 spawning season. under natural conditions weakfish larval development is ca. 3 wk, and we ran separate experiments with larvae of five different ages (5, 8, 11, 14, and 17 d post-hatching). We used two different size classes of rotifers (Brachionus plicatilis) and brine shrimp nauplii (Artemia sp.) as prey organisms. Contrary to results of previous research, weakfish larvae did not select prey based on size alone. When prey abundance was above 100 itemsl-1 weakfish, larvae always chose large rotifers (length = 216 m) over small rotifers (length = 160 m). At 11 d post-hatching, larvae switched their diet from large rotifers to small brine shrimp nauplii (length = 449 m); however, when fed small rotifers and small brine shrimp nauplii the change in diet occurred at 14 d post-hatching. This pattern of selectivity was maintained in each larval age class. Early-stage larvae (5 and 8 d post-hatching) did not feed selectively when prey abundance was less than 100 itemsl-1. Late-stage larvae (17 d post-hatching) fed selectively at abundances ranging from 10 to 10000 items-1. Lwimming speeds of prey items, which ranged from 1 to 6 mms-1, had no consistent effect on prey selection. These results suggest that weakfish larvae are able to feed selectively, that selectivity changes as larvae age, and that selectivity is also influenced by prey abundance. 相似文献
546.
Fe(III)/Cr(III) hydroxide, a waste material from the fertilizer industry, has been used for the adsorption of Cr(VI) from aqueous solution, over a range of initial metal ion concentrations (5-30 mg litre(-1)), agitation times (1-180 min), adsorbent dosages (100-1200 mg per 50 ml), temperatures (24, 29 and 38 degrees C) and pH values (4.5-10). The adsorption of Cr(VI) increased with the initial concentration of Cr(VI) and with temperature. The process of uptake follows both the Langmuir and the Freundlich isotherm models. The applicability of Lagergren and empirical kinetic models has also been investigated. Almost quantitative removal of Cr(VI) at 10 mg litre(-1) in a 50-ml solution by 500 mg of adsorbent was found at an equilibrium pH of 5.6. The efficiency of chromium removal was also tested using wastewater from the chromium plating industry. 相似文献
547.
Cellulose decomposition in soils amended over twenty year ago with heavy metal-contaminated sewage sludges was assessed by using the cotton-strip assay. The soils of the Luddington Experiment now contain concentrations of Cu, Ni and Zn in selected plots that approximate to or exceed the statutory limits for these elements in sewage sludge-amended soils. The rates of cellulose decomposition were generally lower in the plots with elevated metal concentrations, relative to uncontaminated sludge-amended and unsludged controls. Generally, the metal-rich plots showed reductions in the time taken to reach 50% cotton-tensile-strength loss (CTSL). However, the reductions could not be consistently related to any one metal. The difference in decomposition rates between treatments was systematically reduced over the duration of a time-course experiment. A lower initial population of the appropriate decomposer community of micro-organisms may account for the observed short-term lag in decomposition rates. 相似文献
548.
The blowfly Lucilia sericata has been reared on artificial diets containing from 0 to 200 mg Cd kg(-1) at population densities ranging from 8 larvae per 4-g diet to 8 larvae per 32-g diet. Peak larval weight, development period, pupal weight, adult-emergence weight, and fecundity were measured. Larvae of blowflies respond to food deprivation by a reduction in larval weight and subsequent pupal and adult size. Contaminating the food supply with cadmium produced similar additive effects, reduced the growth rate, and increased the age of pupation. The results are of importance in determining the effects of environmental pollutants on population dynamics. 相似文献
549.
López Gappa J Tablado A Magaldi NH 《Environmental pollution (Barking, Essex : 1987)》1993,82(2):157-165
Seasonal changes in structure of a rocky intertidal community affected by sewage pollution at Quequén (Argentina) were studied over a period of 2 years. Most species showed a decrease in cover values in the polluted area. On the other hand, a small proportion of organisms favoured by organic enrichment predominated around the outfall during the period of study. Community structure was not significantly altered by frosts or windstorms. Desiccation is identified as the main physical stress. A combination of late spring high temperatures with extreme midday low-tides caused by northerly winds was responsible for heavy losses in dominant algae. Major seasonal changes in community structure were primarily due to variations in area covered by the chlorophyte Ulva lactuca, and crusts of blue-green algae and diatoms in the vicinity of the outfall. Highest diversity values were attained during either late winter or spring, due to increased abundances of several seasonal algae. Abundance of the dominant organism, the bivalve Brachidontes rodriguezi, remained stable, showing only slight, non-seasonal, changes. Since the absence of B. rodriguezi is an indication of heavy pollution, temporal stability of this species suggests that the intensity of sewage discharges did not vary over the period of study. 相似文献
550.
Forty test subjects who, either during or after the reactor accident of Chernobyl (26th April 1986), stayed at a building site at Shlobin 150 km away, were examined for spontaneously occurring as well as mitomycin C-induced Sister Chromatid Exchanges (SCE). The building site staff, who underwent a whole-body radionuclide count upon their return to Austria (June through September 1986), were used for the cytogenetic tests. The demonstration of the SCE was made from whole-blood cultures by the fluorescence/Giemse technique. At last 20 Metaphases of the 2nd mitotic cycle were evaluated per person. The radiation doses of the test subjects were calculated by adding the external exposure determined on the building site, the estimated thyroid dose through I-131, and the measured incorporation of Cs-134 and Cs-137. The subjects were divided into two groups for statistical analysis: One was a more exposed group (proven stay at Shlobin between 26th April and 31st May 1986, mostly working in the open air) and the other a less exposed group for comparison (staying at Shlobin from 1st Juni 1986 and working mainly indoors). Results. A variance analysis according toKruskal andWalis showed an only partially significant increase of spontaneous SCE in lymphocytes of the higher exposed group (m=7,7 exposed group, m=7,0 control group). Mitomycin C-induced SCE were significantly reduced in the exposed group (m=31,6 exposed group, m=39,3 control group). 相似文献