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1.
High-resolution electron capture gas chromatography was used to determine residue levels of organochlorine pesticides in 13 commercially important fish species collected from the NW Arabian Gulf. While most of the residues were below the detection limit of 1 μg kg?1 wet weight, relatively low concentrations of ΣDDT, endrin and dieldrin were detected in the edbile tissue of these fishes. The ΣDDT residue levels ranged from 2 to l 1μg kg?1 wet weight, endrin ranged from none detected (nd) to 45 μg kg?1 and dieldrin from nd to 5 μg kg?1. A definite correlation was established between total organochlorine pesticide residues and lipid content (r = 0.6) for the NW Arabian Gulf fishes. Comparison with fish from Hor-al-Hammar Lake (an area that used to be sprayed with pesticides) has shown that the latter contained significantly higher residue levels. The ΣDDT residue levels ranged from 5 to 45 μg kg?1 wet weight, endrin from 3 to 83 μg kg?1 and dieldrin from nd to 4 μg kg?1 Based upon the observation that the original DDT (p, p′-DDT) was identified in the NW Arabian Gulf fishes, it has been concluded that there was a recent input of DDT to this region. Since DDT application has been banned in Iraq, consequently it was assumed that DDT must originate from a more remote source.  相似文献   

2.
Scats of the European otter (Lutra lutra) were sampled along the Allier river (France) catchment for organochlorine toxic compounds (nine pesticides and 16 PCBs congeners) measurement. From early 2004 to June 2005, 90 sites of 40 rivers were twice investigated, and 71 scats samples collected, in four geographical areas being naturally re-colonized by the species since its legal protection. Detectable pesticides and PCBs were found in 100% of the samples. Mean values reached 2.72 and 13.58 mg kg?1 (lipid weight) for pesticides and PCBs, respectively. Amounts were significantly different between the four areas investigated. A significant increase in medium and absolute values is noted by going downstream of the catchment. Potential medium- and long-term consequences on the observed population increase are discussed.  相似文献   

3.
Analysis of PCB, DDT, and chlordane contamination in selected finfish and shellfish species from estuarine and coastal marine waters of New Jersey (U.S.A.) indicates consistently highest organochlorine contaminant levels in samples from the north and northeast regions of the state in proximity to industrialized sites. Gas chromatographic analysis of tissue samples from three finfish species (bluefish, Pomatomus saltatrix; striped bass, Morone saxatilis; weakfish, Cynoscion regalis) and one shellfish species (blue crab, Callinectes sapidus) collected throughout the state during the 1986–1987 and 1988–1991 sampling periods revealed mean PCB, DDT, and chlordane concentrations ranging from 200–5, 380 µg g-1 wet weight, 25.14–492.52 µg kg-1 wet weight, and 5–106.44 µg kg-1 wet weight, respectively. A major conclusion of this study is that some commercially and recreationally important finfish and shellfish species in New Jersey waters, especially those which are lipid-rich, have continued to accumulate PCBs, DDTs and chlordane from the environment long after restrictive regulations were first placed on their use in the United States during the 1970s. The greatest impact of organochlorine contamination is nearby urban centers, most notably Newark and New York City.  相似文献   

4.
Fish and piscivorous bird eggs collected in 2003 from Lake Maggiore (Italy), were analysed for PCB and DDT contamination. Lake Maggiore has been severely polluted by DDT through production of the pesticide within its catchment. Although agricultural application of DDT was banned in Italy in the 1978, industrial production continued until 1996, with enough contamination of water and soil for serious bioaccumulation in the lake biota. PCB and DDT concentrations in a whitefish (Coregonus macrophthalmus Nusslin 1882) were seen to be dependent on season and fish age, but not on sex. The average increase of the lipid-normalised concentration of DDTs and PCBs was two-fold across season and also across age, resulting in an overall increase of four fold. The seasonal variation was related to the eco-physiological cycle of the fish and to the contamination dynamic of the lake, while the effect of the fish age was explained on the base of biomagnification-related mechanisms. A fugacity model was applied to predict the age-dependent bioaccumulation potential of PCBs, whose concentrations were rather stable in recent years in the lake. Predicted values for compounds with negligible biotransformation were in good agreement with experimental data (calculated vs. experimental mean difference of 14%), and a relationship between the increase of experimental age-dependent concentration and K ow was observed. The good correspondence between the predicted and the measured values for most PCB congeners confirmed the general inability of fishes to biotransform these compounds. On the contrary, the importance of biotransformation processes was recognised in birds; eggs of a fish eating bird (Podiceps cristatus) from the same area selectively bioaccumulated p,p′-DDE. For PCBs, congener 149 appears to be completely metabolized by the bird species, and congeners 95, 101, 132, 151 and 174 were reduced as well. The role of the metapara free position on at least one phenyl ring of PCB congeners in biotransformation processes was confirmed.  相似文献   

5.
Sunfish (Lepomis auritus and L. macrochirus) were used to monitor polychlorinated biphenyl (PCB) contamination in a group of small streams flowing into a larger stream/reservoir system. Mean PCB concentrations in sunfish appeared to reflect exposure conditions at the site of capture. Fish from uncontaminated sites 1 to 2 km distant from PCB-contaminated sites did not exhibit PCB contamination, and PCB concentrations in fish downstream from a discrete source decreased at a rate greater than or equal to downstream dilution of the point source. Mean PCB concentrations in fish near the source exhibited relatively large (-40%) fluctuations between semi-annual sampling periods, suggesting that PCB concentrations in sunfish populations may respond rapidly to changes in exposure. Sunfish were not sensitive enough indicators of contamination to use in assessing whether or not problematic levels of contamination may occur in other species. Although the presence of PCB contamination in sunfish can be used to infer that PCBs are elevated in other species, the absence of PCB contamination in sunfish cannot be used to infer that older, fattier fish higher up the food chain are uncontaminated.  相似文献   

6.
Organochlorine pesticide residues and PCBs were measured in 113 otter (Lutra lutra) scat samples from 94 sites in the River Clyde catchment, its estuary and neighboring coastal waters in western Scotland. Contents of pesticide residues were generally low. PCB amounts were high in some regions in the study area (geometric mean contents up to 19.5 mg kg?1 lipid). Potential sources of contamination included industrial areas, a sewage sludge dump and shipping facilities, both naval and commercial. PCBs in tissues were estimated from scats. Analysis of scats provides a useful technique of estimating potential contamination threats to otter populations and can be used to identify biologically significant hot-spots of contamination which may be missed by more familiar surveillance methods.  相似文献   

7.
Trace metals: Cd, Cu, Cr, Ni, Pb and Zn and persistent organicpollutants: polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) were investigated in a fraction ofsediments characterized by a granulometry < 200 μm. Coresfrom 17 to 54 cm depth, were collected at two sites of theSeine river upstream (Port à l'Anglais) and downstream (Saint-Cloud) from Paris and at one site of the Marne river (Saint-Maurice). Marne river sediments displayed higher Cu andPb levels than those of the Seine river. Except for Cd and Cr,contents did not vary notably in the Seine river sediments.Metal contents, except Pb, were significantly correlated withthe sediment fraction which granulometry is < 50 μm,particularly at Port à l'Anglais (p < 0.001). Correlationcoefficients between Cr, Cu, Ni and Zn contents and clayfractions of the cores ranged from 0.85 to 0.99 at both sitesof the Seine river. PCB levels varied widely, ranging from 27to 689 μg kg-1 and were highly correlated with bothsediment fraction < 50μm and particulate organic carbon(POC) ratio. PAH levels ranged from 2.30 to 41.3 μg g-1 and displayed the highest values close to dams; theyshowed no correlations with sediment fraction < 50 μm and POC.  相似文献   

8.
Biphenyl and several plant secondary metabolites (PSM) (carvone, isoprene, limonene, naringin, and coumarin) and surfactant (hydroxypropyl-β-cyclodextrin, (HP-β-CD)) have been shown to improve aerobic polychlorinated biphenyl (PCB) removal by several bacterial species. The objective of this study was to determine whether these treatments also affect PCB removal and microbial community structure in a high organic matter soil (Pahokee soil series with 67% organic matter) and low organic matter soil (Woolper soil series with 6% organic matter), as determined by monitoring changes in PCB levels and phospholipid fatty acids (PLFA) profiles in laboratory microcosms amended with these compounds. Biphenyl enhanced di-chlorinated and tri-chlorinated biphenyl removal in both soils, but PSM did not improve removal of these congeners. On the contrary, HP-β-CD decreased PCB removal when used in combination with biphenyl. Two-way analysis of variance indicated that HP-β-CD significantly increased tetra- and penta-chlorinated biphenyl removal from the high organic matter soil, but not from the low organic matter soil. Principal components analysis of PLFA data indicated that HP-β-CD increased proportions of 18:1ω7c associated with Gram-negative bacteria, but decreased 10me16 and 10me17 lipid associated with Gram-positive bacteria, while biphenyl and PSMs had no detectable effects on soil microbial communities. PCB removal was not correlated to any PLFA. In conclusion, PSM previously shown to enhance PCB removal in soil-free systems were not effective in two divergent soils evaluated in this study, and HP-β-CB had increase, decrease, or no effect on PCB removal depending on types of PCB congeners, soils, and co-amendments.  相似文献   

9.
Natural entomopathogenic nematode (EPN) populations were surveyed in La Rioja (Northern Spain) during two consecutive years (2003–2005) to study their diversity, occurrence, and life characteristics under different agricultural management representing natural areas and perennial and annual crops from organic and conventional systems. Native EPN species and strains were identified using morphological and molecular characteristics. Virulence, infection cycle length and reproductive potential were assessed using Galleria mellonella larvae. The EPN occurrence was evaluated through abundance, recovery frequency, larval mortality percentage and EPN population density. EPNs were also related to selected soil physical and chemical variables as well as to some soil pollutants such as heavy metals and organochlorine pesticide residues. Only two steinernematids species were identified: Steinernema feltiae was observed throughout all seasons from natural and agricultural areas and Steinernema carpocapsae in summer and autumn of 2004 from perennial crops only. The virulence of native strains was lower than other previously isolated Spanish strain from natural areas or crop field edges. EPN abundance and recovery frequency indicated that habitat type might influence EPNs occurrence stronger than seasonality with the intensity of agricultural management inversely affecting their distribution. Moreover, clay, P2O5, Zn, Cu and hexachlorobenzene contents negatively correlating with EPN population density. We consider that agricultural management should be taken into account if EPNs are going to be used as biological control agents.  相似文献   

10.
The aim of this study was to assess the PCB pollutionof the South-Western branch of Lake Como by using thezebra mussel (Dreissena polymorpha) as abioindicator since its recent reintroduction. Someenvironmental and physiological variables influencingaccumulation processes of organochlorine compounds inDreissena were investigated because climaticfactors may affect life cycle, reproductive stage andage. PCB levels were highest in the soft tissues ofDreissena close to the industrialized area ofComo (2298 ng g-1 of lipids) and slowly decrease goingnorth, reaching approximately half this value at theclosing section of the lake branch. Nonetheless, thePCB concentrations are well below the dangerous levelsfor the aquatic environment.  相似文献   

11.
To examine whether their strongly hardened cuticle permits adult oribatid mites (Acari) to live in enemy-free space, we investigated (1) if Pergamasus septentrionalis, a widespread and abundant predatory mesostigmate mite species, is able to feed on oribatid mites, (2) if this predator preferentially feeds on certain oribatid mite species and (3) to what extent oribatid mites are consumed compared to collembolans and juvenile Mesostigmata. Single adult individuals of six different oribatid mite species (Steganacarus magnus; Nothrus silvestris; Damaeus riparius; Liacarus coracinus; Eupelops plicatus; Achipteria coleoptrata), one collembolan species (Folsomia quadrioculata) and juvenile Pergamasus spp. were offered separately to adult P. septentrionalis in a no-choice feeding experiment. The predators quickly and preferentially fed on collembolans and juvenile Pergamasus; three oribatid mite species were occasionally eaten (L. coracinus, N. silvestris, A. coleoptrata); the other oribatid mite species were rejected as food (E. plicatus, S. magnus, H. riparius). When preying on oribatid mites, P. septentrionalis typically first cut off the legs of the mite, then opened the body through the region of the genital plates or the mouthparts. The results suggest that predator pressure on adult oribatid mites in the field is low, since few relevant predators at the study site are more abundant and powerful than P. septentrionalis. Adult oribatid mites therefore likely indeed live in enemy-free space, i.e. are little affected by predators, but that may not apply to soft-bodied immatures. Collembolans were quickly consumed indicating that they comprise a major part of the diet of P. septentrionalis. Strong feeding on juveniles of Pergamasus suggests that P. septentrionalis also functions as an intra-guild predator.  相似文献   

12.
Fatty acid (FA) analysis investigates changes in the relative contribution of prey from major energy channels in decomposer food webs for predator nutrition. Adopting this approach we investigated whether the trophic niche of centipedes, as major invertebrate predators in forest soil food webs, changes with maturation, season or forest age. Generally, each of the four centipede species studied differed significantly in their FA composition suggesting trophic niche differentiation. FA profiles differed more strongly in the two geophilomorph (Strigamia acuminata and Geophilus ribauti) than in the two lithobiomorph species (Lithobius crassipes and Lithobius mutabilis) suggesting that in particular the former feed on markedly different prey. FA profiles changed during post-embryonic development in each of the four centipede species. Differences were most pronounced in the two lithobiomorph species shifting to predominantly fungal feeding prey. Further, FA profiles varied with season indicating that centipedes exploit more prey out of the bacterial channel in autumn. FA profiles of centipedes varied little with forest age suggesting that soil food webs are remarkably invariant across different forest ecosystems. The results indicate that FA composition of second order consumers closely reflects changes in diet of prey species and composition of basal resources. The study proved FA profiles as powerful tool to gain insight into critical characteristics of soil food web stability, i.e., compartmentalisation and the relative importance and variability of energy channels.  相似文献   

13.
Air pollution and atmospheric deposition by PCBs and organochlorine pesticides (isomers of HCH and p,p′-DDE) were studied at Paris from January 1986 to June 1987. The deposition measured as total (wet plus dry) was also followed during 1986 on two suburban and two rural sites. The distribution of the pollutants between the vapor phase and aerosols was evaluated by sampling air through a glass microfiber filter connected to a Tenax resin cartridge. The study shows that in the atmosphere as in waters of the catchment area of the Seine river, PCBs are the main organochlorine pollutants. Pollution by OCL is of the same order as the one described in literature (mean γ-HCH concentration 1.4 ng m?3) while PCB concentrations in the atmosphere are equal to or higher than those observed in USA and Europe (range 5 to 44 ng m?3). On the average, 93% of the PCBs are in the vapor phase with a composition approximating Aroclor 1242. In aerosols and precipitations the composition is closely related to Aroclor 1254. The total fallout for 1986 was 40 μg m?2 for PCBs and 20 μg m?2 for γ-HCH, rainfall being 611 mm.  相似文献   

14.
Reintroduction of extirpated populations creates a unique context that can exacerbate the effects of interactions among species. Thus, reintroduced populations may be particularly vulnerable to predators and competitors, including native species with which they historically coexisted. In this study, we evaluated the effect of native fishes on survival of reintroduced Atlantic salmon (Salmo salar) in the Connecticut River basin, where the native salmon population is extinct. Juvenile salmon are stocked annually in many Connecticut River tributaries. We sampled salmon reintroduction sites across tributaries with different fish communities to determine whether native fish reduce the success of salmon reintroductions (N = 19 site-years). Increased density of slimy sculpin (Cottus cognatus), a native generalist predator, was associated with reduced recruitment of reintroduced salmon. Salmon first-summer survival declined with increased sculpin density across sites, and low first-summer survival led to reduced densities of overyearling salmon the subsequent year. Hierarchical partitioning analysis showed that the negative relationship between sculpin and salmon was independent of potentially confounding variation in other fish community or habitat characteristics. Negative effects of native, historically-sympatric species, particularly generalist predators, can impede restoration of extirpated populations.  相似文献   

15.
Patagonia fishless ponds have been stocked with fishes for recreational purposes since early in the 20th century. We carried out a summer plankton sampling in 18 Patagonian lakes; 12 fishless, 5 with introduced fishes and 1 with endemic fish fauna. The lakes are situated on a latitudinal gradient from 39° to 49°S. Zooplankton and phytoplankton composition, phytoplankton relative abundance, and zooplankton body size and mouthpart morphology were analyzed. Results showed differences between lakes with and without fishes; in the presence of fish zooplankton size spectrum tended to be narrower because of the disappearance of Daphnia and large centropagid copepods. Zooplankton composition changed: centropagid species richness decreased and rotifers dominated. Contrarily, in fishless lakes 3 or 4 centropagid species, differing markedly in body size and exploiting different food niches, were observed co-occurring. These changes in zooplankton seemed to cascade down to phytoplankton. Fish introduction increased the phytoplankton similarity in lakes even belonging to different basins in a latitudinal gradient. Indeed, cyanobacteria dominated only in lakes with introduced fishes. Probably the elimination of Daphnia favored cyanobacteria proliferation due to nutrient rebalance. As a consequence, water quality decreases and the value of sport fisheries is reduced. Fish introduction in Patagonia is a practice that should be re-evaluated by governments and NGOs due to its potentially negative impact on lakes and local economies.  相似文献   

16.
The endangered Sonoran topminnow Poeciliopsis occidentalis has steadily declined in distribution and abundance in the past several decades, and currently survives in the United States only in several isolated localities in southern Arizona. This reduction is correlated with, and primarily attributed to, habitat destruction, and introduction and establishment of mosquitofish Gambusia affinis and other exotic fishes. Topminnows have characteristically been reduced in number or replaced within a year or two of introduction of non-native fishes. Other native fishes have experienced similar declines after introduction of exotics, and much of the endemic western ichthyofauna may be vulnerable to extirpation in this manner. Predation by introduced fishes on natives appears to be a likely mechanism of replacement.  相似文献   

17.
Herring ( Clupea harengus) (as well as sprat and mackerel) is a fish species intensively harvested by the Polish fishing fleet. Its relatively low price and the habits of Polish consumers contribute to its high economic importance in Poland. Among 125.6 thousand tons of marine fish harvested in 2006, herring constituted 22.2 thousand tons (including 7.6 thousand tons harvested from the North Sea). Fish are usually subjected to various culinary treatments, which can influence the concentrations of contaminants in final products. Therefore, the present study aimed at determining the effect of three non- ortho-polychlorinated biphenyl (PCB) congeners (PCB 77, PCB 126, and PCB 169) and three mono- ortho-PCB congeners (PCB 114, PCB 156, and PCB 157) in the tissues of herring slices. Concentrations of dry matter and lipids in the final product were increased by 15.9 and 20.5%, respectively. Brining, which preceded the process of smoking, did not significantly influence concentrations of PCB congeners in herring slices. However, smoking resulted in significant ( p < 0.05) changes in concentrations of three non- -ortho PCBs. The biggest dynamics of losses in relation to smoking duration was observed for PCB 77 (30.2%). For PCB 126, the biggest losses occurred after 1 h of drying, followed by slight changes after 1.5 and 2 h of proper smoking and another increase of losses in the final product after 2.5 h. The duration of smoking did not significantly influence PCB concentrations in wet weigh, as their losses in lipids were much bigger. The observation is derived from strong negative correlations between concentrations of the congeners in lipids and lipid concentrations in herring slices during hot smoking ( r ranging from -0.824 to -0.950). Although the lipid concentration in the smoked fish increased, the PCB content diminished. It shows that during drying of the fish slices, PCBs codistilled with water vapor, settling on the walls of the smoking chamber and smoking trolleys. During the proper smoking, the compounds released with the smoke back to the smoking chamber and settled on the surface of smoked fish together with the disperse phase of the smoke (aerosol). Hot smoking contributed to a reduction of toxic equivalents (TEQs) by 22.7% (converted into lipids 41.9%), and in the final product, it amounted to 0.0188 +/- 0.0023 ng TEQ/kg of wet weight (0.0977 +/- 0.0064 ng TEQ/kg of lipids). The reduction was significantly higher than resulting from hot smoking of mackerel slices, when TEQs were reduced by 17.9% wet weight (converted into lipids 31.7%).  相似文献   

18.
The panphytophagous oribatid mites Scheloribates laevigatus, Achipteria coleoptrata and Galumna elimata were reared under laboratory conditions on the green bark alga Desmococcus vulgaris (syn. Protococcus viridis), grass and herb litter (Holcus lanatus, Hypericum maculatum and Acetosella vulgaris) including fungi growing on the litter, and filter paper. Food preferences, defaecation, gut contents and types of food boli were studied in order to assess the consumption and digestion of the offered diets. The mites consumed all the offered diets including fungi growing on litter. Marked differences in food preference between the alga and litter and no marked differences among mite species were observed. No visible differences in the degree of digestion of the three offered diets among the species were found. The fungal and hyphal cell walls looked undamaged after the gut passage in all species. About the half of the algal cells were damaged mechanically and the contents of cells were digested. The fungi growing on litter were digested similarly. Litter was cut in small pieces by chelicerae, and no conclusions can be made about its utilisation. The results are discussed in view of the knowledge about the enzymatic equipment of the three oribatid species and recent feeding guilds.  相似文献   

19.
The body size of univoltine insect species generally decreases with increasing altitude or latitude. This pattern may have arisen from adaptations to multiple factors that potentially affect body-size variation, such as temperature, food, and interspecific interactions. We examined altitudinal variations in life history and body size, and their relationships to temperature and food resources in two ground beetle species of the genus Carabus (subgenus Ohomopterus; C. tosanus and C. japonicus) in a mountainous area (altitude 860–1730 m) of Shikoku Island, Japan. Larvae of these species are specialist predators of earthworms. The body size of C. tosanus decreased with an increase in altitude. Carabus japonicus, which is much smaller than C. tosanus, exhibited similar sizes across altitudes, although it was not abundant at high altitudes. Available cumulative temperatures for larval development were limited at higher altitudes, and C. tosanus started reproducing 1 month earlier at higher than at lower altitudes. Earthworms (larval food) were less abundant at higher than at lower altitudes. This may imply that food resources also restrict the optimal body size of C. tosanus at higher altitudes.  相似文献   

20.
From 1987–1990, uncontaminated Asiatic clams (Corbicula fluminea) were placed in cages and transplanted into two streams receiving industrial discharges to help identify and quantify polychlorinated biphenyl (PCB) contamination to the streams. Clams accumulated substantial PCB residues at most sites monitored, with the exception of the sites closest to chlorinated discharges. Clams placed nearest to the chlorinated stream reaches consistently underestimated PCB contamination, based on the amount of PCBs found in fish and sediment at those sites. In a separate experiment, clams exposed in stream-side tanks to untreated (total residual chlorine ranged from 0.02–0.07 mg?1 L daily) and dechlorinated stream water exhibited differing degrees of valve movement, growth, and PCB accumulation after a four-week exposure to the two treatments. Clams exposed to untreated (chlorinated) stream water closed their shells more often, exhibited less growth, and accumulated substantially lower PCB concentrations than clams exposed to dechlorinated stream water. Clams apparently close their shells to avoid chlorine exposure, thus isolating clam tissues from PCBs found in the stream water and in the clams' food. Because chlorine and PCBs occur together in many industrial discharges, this finding is a significant consideration for monitoring programs that utilize clams to assess PCB bioavailability.  相似文献   

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