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41.
Environmental Accumulation of Airborne Fluorides in Romania   总被引:2,自引:0,他引:2  
The nature and extent of pollution from an aluminium smelter and a fertiliser factory in Romania were studied. These are large industrial complexes, and both types of industry are known to release fluorides into the atmosphere. In grass samples collected from around the aluminium smelter, the maximum fluoride levels were found to be 4023mgkg–1 and 162mgkg–1 in unwashed and washed grass samples respectively, and 89mgkg–1 in soils. For the fertiliser factory, the maximum levels in washed grasses were found to be 207mgkg–1, and 11mgkg–1 in the soils. In both locations, these maximum values were obtained in samples collected from within 200m of the factory limits, and compare with regional background levels of less than 10mgkg–1 for grasses and 2mgkg–1 for soils. The high fluoride levels of fluoride in the grasses are sufficient to give cause for concern for the effects that these could have on the local population and on grazing animals.  相似文献   
42.
Increasing concerns over rising intersexuality in the animal kingdom and the ability of certain chemicals to disrupt the endocrine system have demanded a better understanding of the costs associated with such conditions. Whilst intersexuality appears relatively widespread throughout gonochoristic crustaceans, i.e. those crustacean species with two separate sexes, the fitness costs have rarely been reported. Through comparable investigation of normal and intersex specimens of the highly abundant marine/estuarine amphipod Echinogammarus marinus (Leach) these fitness costs were determined. Measurements taken to assess fitness costs included fecundity, fertility and embryonic development, maturation period, and any morphological deformities that might result in reduced pairing success. Results from this study suggest that intersex E. marinus suffer from reduced fecundity and fertility, and mature at a larger size than normal specimens. These fitness costs can also, to a certain extent, be related to the degree of intersexuality. It is suggested that the increased size and morphological abnormalities observed in intersexes may result in reduced pairing success. Investigations into intersex organisms, i.e. those organisms with known dysfunctional endocrine systems, and the costs associated with such conditions, should aid researchers in assessing effects at the population and community level.Communicated by J.P. Thorpe, Port Erin  相似文献   
43.
Summary The mating systems in a population of dunnocks included monogamy, polygyny, polyandry and polygynandry. Broods were provisioned by lone females, by females with the part-time help of one male, by females with the full-time help of one male (pairs) or by females with the part-time or full-time help of two males (trios). We compared provisioning of nestlings in these different systems and used the results of natural and experimental removals to examine how individuals reacted to the provisioning by others. In pairs, males and females provisioned at similar rates (Fig. 2a). In trios, females and alpha males fed chicks at the same rate, and at a higher rate than beta males (Fig. 2b). Females attained maximum male help when two males shared provisioning equally (Fig. 6). Females were more likely to achieve this when they were able to escape alpha male guarding during the mating period and exercise some control over mating access by the two males (Fig. 7). Female provisioning did not increase when their help was reduced from two males to one (Fig. 4 a), but it did increase when male help was further reduced to either one male's part-time help (Fig. 5 a) or no male help (Fig. 3 a). Beta males increased their provisioning rate when alpha males were removed from a trio (Fig. 4b). Alpha males may have increased their rate when beta males were removed but any reaction was small. When one male was removed from a trio, the remaining male's provisioning rate was as expected for a male in a monogamous pair. When reactions occurred, they were not sufficient to compensate for the loss of the removed adult and nestling weight was reduced. We discuss the relevance of these results to the maintenance of parental care by pairs and trios.  相似文献   
44.
A seasonal study of arsenic in groundwater,Snohomish County,Washington, USA   总被引:2,自引:0,他引:2  
A series of arsenic poisonings near Granite Falls in Snohomish County, Washington, were identified during 1985–87. An initial investigation revealed the source of arsenic exposure to be high levels of arsenic in well water. A large number of wells in eastern Snohomish County were tested, residents were interviewed and sources of contamination, both natural and man-made, were investigated. More than 70 private drinking-water wells were found to contain elevated levels of arsenic . One well contained 33 mg As L–1. The finding of elevated arsenic levels in a previously approved drinking-water well for a restaurant, plus suggestions of symptoms consistent with arsenic poisoning among people with wells with no detectable arsenic, raised concern over possible temporal variation in arsenic levels. To evaluate this temporal variation, a 12-month study of arsenic in groundwater was conducted in selected wells near Granite Falls. The 12-month study of 26 wells, conducted between February 1988 and January 1989, found arsenic levels for individual wells to vary from one to 19 fold over time. Because of this variability, four out of the eight wells with arsenic levels close to the Maximum Contamination Level (MCL) of 0.050 mg As L–1 would have been considered safe on the basis of a single sample, but would have exceeded the MCL at another time of the year.In areas with a high occurrence of arsenic contaminated drinking water, approval of well water prior to the sale of a house or issuance of a building permit which is based on a single arsenic test may result in later findings of unacceptable drinking water. When the arsenic is near the MCL, it may be prudent to follow well-water arsenic concentrations over time to assure that the arsenic level remains within acceptable bounds. If lower arsenic standards are adopted for drinking water, the issue of temporal variation around the standard will become a matter of more widespread concern.To whom correspondence should be addressed. The contents of this paper do not necessarily reflect the views and policies of the US Environmental Protection Agency.  相似文献   
45.
Previous studies have highlighted a reduction in occurrence and biomass of Ulva lactuca L. (Chlorophyceae) on shores where inputs of colliery waste occur. It was postulated that this was owing to an abrasive effect of colliery waste on macroalgal fronds. To test this, individual U. lactuca plants were exposed to colliery waste (three different grain size categories: < 500 microm, 500-2000 microm, and 0-2000 microm) in both shaken (turbulent) and still conditions in the laboratory. Over an 8-day period, U. lactuca plants lost weight when colliery waste was present and gained weight when no colliery waste was present. Weight loss was most pronounced in U. lactuca exposed to colliery waste of 500-2000 microm grain sizes in shaken conditions (- 18.8% +/- 4.65 SE, n = 4). However, greatest weight gain (+ 26.8% +/- 6.26 SE, n = 4) also occurred in the presence of colliery waste (0-2000 microm), but in still conditions. Weight gain was also observed after 60 days in still conditions in the presence of colliery waste (grain sizes 0-2000 microm); U. lactuca showed significant growth (+ 69% +/- 67 SE of starting weight, n = 5) compared with controls (- 51% +/- 41 SE, n = 5). These results suggest that 'large' grains of colliery waste act as a physical abrading agent on macroalgae when in turbulent conditions, and may be responsible for lowering of species richness of macroalgae where colliery waste inputs occur. However, by contrast, colliery waste in still conditions promotes the growth of U. lactuca, suggesting that, for example, rock pool flora may benefit from its presence  相似文献   
46.
A large proportion of leaf fluoride consists of surface deposits and a sucking herbivore would be expected to take in a smaller load of fluoride in its food than a chewing herbivore. In these experiments, fluoride was applied aerially, through the leaves, and systemically, via the roots, to compare uptake by aphids and effects on their fecundity. Fluoride applied via roots was taken up by both the plants and the aphids, but at high treatment rates the aphids had much lower concentrations than the foliage. When the plants and aphids were fumigated with HF the aphids had much greater loads than the plant shoots, which was due to deposition of F on the insect surfaces. There were no effects of the treatments on aphid reproduction or development time. The aphids obtained some fluoride through their diet which suggests that fluoride is present in the phloem sap, previously thought to be of minor importance.  相似文献   
47.
Mormede S  Davies IM 《Chemosphere》2003,50(4):563-574
Polychlorobiphenyls (PCBs) and pesticides are persistent, semivolatile contaminants whose global circulation is now well established. One of their ultimate sink is the bio- and geo-phases in the deep-sea. We have investigated the distribution of selected PCBs and pesticides with depth and longitude in various deep-sea fish, namely black scabbardfish (Aphanopus carbo), orange roughy (Hoplostethus atlanticus), roundnose grenadier (Coryphaenoides rupestris) and Bathysaurus ferox from Madeira, Sesimbra, the Meriadzec Terrace and Rockall Trough in the North Eastern Atlantic at 1000 m depth, and at 2000 m depth where available. In most species, males presented higher levels of contamination than females. This pattern was probably due to the females eliminating contaminants through egg production. Roundnose grenadier presented higher levels of contamination (mainly p,p'-DDE, CB 153, 138, 180, sigmaCB(24) and p,p'-DDT) in fish caught at 2000 m than at 1000 m depth. Similarly, B. ferox, which is found deeper than the other species studied, showed much higher levels of most CBs and pesticides (lipid normalised) than the other species. Concentrations were up to 10 times higher, and showed differences between water masses.  相似文献   
48.
A literature and questionnaire survey has been carried out in order that a database be developed for PCDD/PCDF levels in ambient air. The data received to date and entered into the database indicates that standardization in methodologies and reporting is required. The overall response to the survey, even with reminders, was disappointing.  相似文献   
49.
This report provides clear evidence of tributyltin (TBT) contamination of coastal waters close to an oil terminal handling large tankers. Dogwhelk populations from Sullom Voe, Shetland, have been examined for the development by females of certain male sexual characteristics (e.g. a penis and vas deferens). This condition, termed imposex, is a response to exposure to tributylin compounds, and can be quantified by use of the relative penis size index (RPSI). Dogwhelk populations throughout Sullom Voe were strongly affected by TBT (RPSI 34 to 81%), and up to 90% of the females in the oil terminal area were sterile. Queen scallops collected in the Voe contained enhanced concentrations of tin in adductor muscle and gonad tissue (0.02 to 0.23 mg kg(-1) wet weight), but it is considered unlikely that their growth and development is adversely affected. Tin was rarely detected in scallops, queens, or dogwhelks outside the Voe, although the development of a vas deferens in many of the female dogwhelks indicated a degree of contamination of the open waters of Yell Sound. TBT was detectable (2 ng litre(-1) as tin) in only two sea water samples taken from the terminal area.  相似文献   
50.
A technique is described that uses artificial resin beads with known surface properties to investigate the factors influencing the bioaccumulation of pollutants from sediments. One advantage of this technique is that it provides a standard procedure against which it is possible to calibrate natural sediments with their diverse properties. The method has been used on third instar larvae of the midge Chironomus riparius and the results are compared with previous studies on the worm Lumbriculus variegatus. The use of a standard test using resin beads as a substitute for natural sediment allows comparisons to be made between species and substrates. Thus, the bioaccumulation factors for the midge larvae are much smaller than those of the worm and this correlates with the ability of the insect larva to detoxify many pollutants. It is also possible to use the test to identify if ingestion of the sediment increases the bioaccumulation of contaminants and whether this involves the release of pollutants by digestive processes or not.  相似文献   
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