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1.
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   

2.
The occurrence and characteristics of chemically-based density stratification in portions of the Seneca and Oswego Rivers, downstream of ion-polluted Onondaga Lake, are described for seven different days in the summer and fall of 1978 and 1981, which covered a wide range of river flows. The results indicate that chemically-based density stratification occurs routinely in the Seneca River downstream of the lake inflow, in response to a continuous chemically-based density difference between the two systems of 0.0015 to 0.0030 g cm?3. The persistence of the phenomenon, and therefore the longitudinal range over which the river stratification occurred, was dependent on the velocity of river flow and the magnitude of the density gradient that bordered the upper river water and the lower released lake water. During the low flows common to summer the stratification extended approximately 14 km downstream to a dam, and 3 km upstream, of the lake outlet — river junction. Vertical mixing between the stratified layers increased as the flow in the Seneca River increased, and as the vertical density gradient decreased. A dimensionless group, $$\frac{D}{{V\left( {\frac{\rho }{{\Delta _\rho /\Delta _z }}} \right)}}$$ where: D = apparent vertical diffusion (m2 hr?1), V = average velocity of the overlying river flow (m hr?1 ), p = density at the interface between the stratified layers (g cm?3), and Ap/Az = density gradient between the stratified layers (g cm?3 m?1), was found to be constant for summer low flow conditions for a 6.5 km length of the Seneca River, thus quantifying the interaction between vertical mixing and the included influences for that portion of the river. The occurrence of chemical stratification in the river had dramatic implications on the corresponding distribution of dissolved oxygen (DO). The isolation of the organically enriched lake water in the lower layer enhanced the depletion of DO there, which resulted in the development of substantial (> 4.0 mg 1?1 ) DO stratification downstream of the discharge from the lake during summer low flow periods.  相似文献   

3.
The effects of many combinations of toxic concentrations of heavy metal pollutants, viz., mercuric chloride, lead acetate, cadmium chloride and cupric sulphate, on the senescence of isolated mature leaves of submerged aquatic plants, Potamogeton pectinatus L., Vallisneria spiralis L., and Hydrilla Verticillata (L.f) Royle were studied. All of the combinations of heavy metal pollutants caused senescence in all three species by decreasing chlorophyll, DNA, RNA, protein and dry wt, and increasing free amino acid, tissue permeability, the activities of protease and RNase, and the ratio of acid to alkaline pyrophosphatase activity over control values. The effects were highest in Potamogeton and lowest in Hydrilla. The degree of senescence in the three submerged plants by combinations of toxic concentrations of heavy metal pollutants is much higher due to synergism than that by individual heavy metal pollutants.  相似文献   

4.
The study was carried out on 3 groups of 10 fish, each fed on a different natural labelled food. The preys selected were a crustacean (Gammarus pulex), a midge larvae (Chironomus sp.) and the soft tissues from a snail (Lymnaea stagnalis), which are usually consumed by carp in the natural environment. The contaminated food consumption by the fish resulted in a 60Co maximum transfer factor ranging from 1.2 × 10?2 to 5.1 × 10?2 depending on the food type. These values, and the contamination kinetics indicate that the biomagnification of the radionuclides cannot occur, even over the long term. 60Co depuration from fish was also influenced by the contaminated food type, previously ingested. The lower elimination rate correspond to the higher value of the transfer factor (Gammarus pulex) and inversely (Lymnaea stagnalis).  相似文献   

5.
Contamination of the Spring River in southwest Missouri by 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) is believed to result from several well-defined point source waste disposal sites. Analyses of 31 fish samples and samples of crayfish, mussels, other aquatic invertebrates, and sediments collected in 1981-1983 demonstrated a rapid decline in TCDD levels in biota both upstream and downstream of the area of contamination and are believed to indicate a continuing, long term input of TCDD into the river. Mean concentrations of TCDD 0.5 km downstream from the area of contamination were 38 parts per trillion (pptr) in whole fish and 20 pptr in fish fillet; mean concentrations beyond 14 km downstream were below 4 pptr in both whole fish and fillets. Caged mussels (65 day exposure) did not accumulate TCDD (detection limit, 10 pptr). High fish consumption by local sportsmen may indicate maximum permissible concentrations of less than 5 pptr. in fish fillets.  相似文献   

6.

Purpose

A multi-compartment monitoring study was performed to characterize the effect of environmental variables, such as temperature and water flow as well as sediment characteristics, on the distribution and transport of persistent organic pollutants (POPs) in a dynamic river system during 1 year in an industrial region in central Europe.

Materials and methods

Waterborne polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed over a period of 1 year at five sampling sites in the Morava River in the Czech Republic. Contaminants were measured monthly in riverbed sediments, freshly deposited sediments, water samples and passive samplers.

Results and discussion

Sediments are the main carrier of POPs in the river. Distinguishable patterns of PAHs, OCPs and PCBs in sediment indicate that their origin is from distinct sources and different transport pathways. The PAHs were identified as the dominant contaminant group of compounds with a mean concentration in sediment of 5,900 μg kg?1. Such concentrations are up to 10 times higher than in the Danube River, into which Morava drains. In contrast, mean concentrations of PCBs, hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane and its breakdown products (DDTs) and hexachlorobenzene (HCB) of 6.0, 0.4, 4.2 and 6.0 μg kg1, respectively, are similar to those in the Danube. With some exceptions, no significant difference in composition of surficial riverbed sediments and those collected using sediment traps was observed. Despite the presence of potential local pollutant sources, the differences in contaminant concentrations between sites in the region were in most cases not significant. Variations in POP concentrations in sediments are mainly induced by high flow events, whereas seasonal variability was not observed.

Conclusions

The changes in contaminant concentrations in Morava River sediments are induced by episodic high flow events that cause erosion of contaminant-containing particles and their deposition at suitable downstream sites.  相似文献   

7.
Distribution of trace metals in the Periyar river has been investigated in detail. The fluvial concentrations of trace metals increase in river water and decrease in sediments during the summer months due to solubilization and concentration by evaporation. The levels, especially of Zn and Cd which are industrial pollutants increase by a factor of 10 both in water and sediments at the industrial zone. The concentration of Cd in the river water approaches the WHO standards for safe limits in drinking water. Solubilization at the backwater zone under high salinity is identified as one of the major mechanisms of trace metal transport to the marine environment. River meandering is responsible for large scale deposition of suspended solids at the industrial zone during the monsoon period. The trace metals exhibit build-up in specific concentration in the suspended solids in proportion to their residence time.  相似文献   

8.
Several types of pollutants are currently entering the territorial waters of Kuwait from a variety of sources. Some pollutants, especially petrochemicals, are known to be potentially mutagenic and/or carcinogenic. Some of these chemical pollutants may enter the tissues of aquatic organisms and eventually the human body. The presence of such chemicals in the marine environment might create a serious health hazard. The marine environment of Kuwait was monitored for the presence of mutagenic chemicals using living organisms such as shrimp, clams and algae as bioindicators. These organisms were collected from selected sites within Kuwait territorial waters. Their tissues were extracted in ethanol and screened for genetically active chemicals by two standard bacterial assays, the Fluctuation Test and the Ames Test. Salmonella typhimurium TA98 was used as a tester strain. The data obtained from this study indicated that the shrimp, algae and clam samples were polluted with low concentration of frameshift mutagens. Due to the limited scope and nature of this study it was impossible to determine the source(s) of input or the chemical nature of these pollutants.  相似文献   

9.
A protozoological survey was performed to analyze the organisms of the subphylum Sarcodina Schmarda, present in waste stabilization ponds located at Santo Tomás Atzingo, México, from March to December 1981. The amoebae isolated were identified and counted. Several physicochemical parameters were also determined and correlated with the biological data. Thirteen amoebic species were isolated and identified: one definite pathogen, Entamoeba histolytica Schaudinn; three species that have shown pathogenic strains for humans: Acanthamoeba polyphaga Page, Acanthamoeba castellanii Douglas, and Naegleria sp. (Alexeieff) Calkins; two opportunist species: Entamoeba coli (Grassi) Casagrandi and Barbagallo, and Iodamoeba bühschlii (Von Prowazek) Dobell; and seven free-living amoebae: Acanthamoeba astronyxis Ray and Hayes, Amoeba proteus (Pallas) Leidy, Hartmannella exundans Page, Hartmannella vermiformis Page, Pelomyxa palustris Leidy, Vahlkampfia avara Page, and Vahlkampfia russelli Singh. A clear correlation between the number of amoebae and the temperature and alkalinity of the system was found. The removal capacity of the ponds for E. histolytica varied from 30 to 100% during the survey. The amoebae showed a succession in space and time in the system studied.  相似文献   

10.
The growth rates of two diatoms, acidophilic Asterionella ralfsii and circumneutral A. formosa, were differentially affected by varying pH, Al, and EDTA in chemically defined media. Free Al ion concentration increased as pH and EDTA concentration decreased. Free trace metal ion concentration decreased as EDTA levels increased but increased by orders of magnitude upon addition of Al. pH had an overriding species specific effect on growth rate; at low pH A. ralfsii had higher growth rates than A. formosa and vice versa at high pH. For both species higher EDTA levels depressed growth rates. Moderate additions of Al generally resulted in growth stimulation. The growth rate stimulations, especially at 200 and 400 μg L?1 Al additions, correlate to increases in free trace metal ion concentrations. The EDTA-AI interaction effects on growth rate were both pH and concentration dependent: at pH 7 both species were stimulated by addition of Al at all EDTA levels (except A. ralfsii at 5.0 mM EDTA and A. formosa at 0.5 mNM EDTA); at pH 6 Al addition either stimulated or had no effect on the growth rates of both species (except at low EDTA and high Al levels); at pH 5 A. formosa did not grow and additions of 200 μg L?1 Al stimulated growth of A. ralfsii. It is likely that the effect of pH, Al, and EDTA on speciation of essential or toxic trace metals affects growth rates of these diatoms in a species specific manner.  相似文献   

11.
The ability of freshwater organisms (mussels — Unio pictorum L. and crustacean plankton —Cladocera and Copepoda species) to monitor heavy metal pollution was compared under field conditions, near the effluent discharge of a sewage water treatment plant at Lake Balaton (Hungary). The mussels were transferred from their less polluted habitat to the study area. The crustacean plankton was collected at this site The concentrations of Hg Cd Cr Cut Pb, Zn, and Fe were measured m the gills of the transplanted mussels as well as the natural zooplankton in the summer period, using the AAS method. Both mussel gills and the zooplankton showed periodically high Fe-, Zn-, and Cu-concentrations. An elevated level of Hg was only observed in mussels, while high Pb- and Cr-concentrations were found only in crustacean plankton. Accordingly the zooplankton seems a more suitable model for monitoring heavy metal pollution under these field conditions.  相似文献   

12.
Two species of lichen native to southwest Lousiana, Parmotrema praesorediosum (Nyl.) Hale and Ramalina stenospora, Mull. Arg. have been investigated as air pollution monitors. Over the period 1983–88 samples were collected at 18 stations in the Lake Charles/Westlake/Sulphur area. The samples were analyzed for A1, Fe, Cu, Pb, Cd, Hg, Cr, and Zn. When metal concentrations in lichens were plotted vs year for certain representative stations, a dramatic reduction in the concentrations of certain metals was seen after 1983. When the most recent data are compared with those previously obtained, the effects of the industrial zone, which was previously demonstrated, have now all but disappeared.  相似文献   

13.
The acute toxicity of commercial herbicide, Paraquat was determined by 96-hr static bioassay on the freshwater chlorophytes Scenedesmus dimorphus (Trup.) Kuetz., Scenedesmus quadricauda (Trup.) de Brebisson and Ankistrodesmus falcatus (Cord) Ralfs. The 96-hr EC50 values of Paraquat for reducing growth and metabolic products of the three algae were determined. The number of days required for cell division increased with increasing Paraquat concentration. The three algae and their test parameters respond differently to Paraquat. Scenedesmus dimorphus was the most susceptible alga and the chlorophyll a was the most sensitive response parameter. On the other hand, the dry weight of the test algae was the most resistant parameter. It was observed that Paraquat has inhibitory effect on the primary producers.  相似文献   

14.
This paper presents the findings of initial investigation of the role of Spartina alterniora Loisel. in the movement of chlorinated hydrocarbons. 14C-polychlorinated biphenyls and technical Aroclor® 1254 were used for the determinations. The findings demonstrate that Spartina accumulates 14C-radioactivity from sand and organic mud soil systems treated with 14C-PCB's. These findings also demonstrate that this plant has the capacity to accumulate 14C-radioactivity to levels elevated above that in the treated soil. Other experiments with Aroclor® 1254 demonstrate that cogeners of Aroclor® 1254 are present in Spartina stem and root extracts. These experiments also suggest that the chlorinated hydrocarbon uptake process is modulated by the plant and that this results in selective cogener uptake. The selectivity appears to be for the lesser chlorinated components of the commercial mixture. Overall, this study suggests that Spartina may act as an initial vector for mobilization of sediment bound chlorinated hydrocarbons to the estuarine food chain.  相似文献   

15.
This study examined the effects of exposing the eggs of the purple sea urchin (Arbacia punctulata) to two commercial polychlorinated biphenyl mixtures (PCB's), Aroclors 1254 and 1016, on fertilization through pluteus (larva) development. Eggs were exposed to various concentrations of the PCB's (0.5, 1.0, 5.0, and 10.0 mg L?1) beginning 25 min prior to insemination, with continuous exposure post-insemination for the 72 hr observation period employed in this study. The PCB's were administered as a component of a filtered sea water (FSW) medium. A FSW control and a FSW-acetone conditioned control where used since acetone was utilized in a 49 : 1, acetone: PCB ratio, to emulsify the PCB's. Since Arbacia eggs cleave synchronously following insemination, the percentage of the eggs cleaving at 1.75 hr post-insemination was used to determine the fertilization efficiency. Pluteus development and morphology was assayed at 24 hr intervals. The results of the fertilization efficiency studies were tested using Chi square and Pearson's-Product-Moment-Correlation Coefficient (r) at a 95% level of confidence. The morphology data were treated with a two-tailed t-test (99% confidence level) and (r). Both PCB's affected fertilization efficiency with the Aroclor 1016 being an order of magnitude more toxic than the Aroclor 1254. Likewise, both Aroclors were toxic to the pluteus development process with Aroclor 1016 being the more toxic of the two mixtures. At the highest PCB level employed, Aroclor 1254 proved more lethally toxic than Aroclor 1016 although both treatment-groups exhibited more than 90% toxicity to the morphogenic process.  相似文献   

16.

Purpose

Few studies have described the bacterial community structures of turbid rivers. In this paper, the characteristics of the bacterial community in the water and surface sediment of the Yellow River, China, the largest turbid river in the world, were studied.

Materials and methods

Water and sediment samples were collected from six sites along the river. Bacterial community composition was determined using the 16S ribosomal RNA (rRNA) gene clone library technique. The relationship between environmental parameters and bacterial diversity was analyzed.

Results and discussion

A total of 1,131 gene sequences were obtained and clustered into 639 operational taxonomic units (at the 97 % identity level), with Proteobacteria as the predominant phylum. The Shannon index for water samples ranged from 3.39 to 4.40 and was generally higher than that in other rivers; this was probably due to the high suspended particulate sediment (SPS) concentration in the Yellow River, which can provide more habitats for both aerobic and anaerobic bacteria. Also, the bacterial diversity of the water samples was slightly higher than that of the surface sediment samples. The bacterial diversity of water increased along the river in the downstream direction, while there was no trend for the sediment. Redundancy analysis indicated that pH, dissolved organic carbon (DOC), and SPS were the main factors controlling the water bacterial community in the Yellow River, and pH, nitrate–nitrogen, and water content were the main factors for the surface sediment bacterial community.

Conclusions

This study indicated that the bacterial diversity of the Yellow River is generally higher than that in other rivers, suggesting that SPS plays an important role in regulating bacterial diversity and community structure in aquatic environments.  相似文献   

17.
This paper deals with the effect of solvents on the pesticide inhibition of ATPase in the gills and brains of a freshwater teleost Labeo rohita after in vitro treatment with chlordane (an organochlorine pesticide) and MetasystoxR (an organophosphate) pesticide after dissolving in different organic solvents viz. benzene, cyclohexane, cyclopentane, dimethylacetamide (DMA), dimethylformamide (DMF), dimethylsulfoxide (DMS), and acetone/ethanol (1:1) mixture. The inhibitory effect of chlordane was greatly reduced by cyclohexane, cyclopentane and benzene, to a less extent by DMA, DMF, and DMS and to a lesser extent by acetone/ethanol (1:1) mixture. ATPase inhibition by MetasystoxR showed less effect on the inhibition of ATPase activities. Effect on the inhibition of Na+, K+-ATPase was observed to be greater than on Mg++ ATPase in both tissues, but the activity of both the ATPase in gill homogenate was decreased compared to brain homogenate. Choice of solvents can have profound effects on the response of ATPase to chlorinated hydrocarbon pesticides.  相似文献   

18.
Coliform and faccal coliform were isolated from drinking water samples obtained from tap water (TW) and storage tanks (ST) in Baghdad city. All isolates were identified and tested for their resistance to twelve antibiotics. Bacterial identification revealed that Ent. cloacae and Kl. pneumoniae were the predominant organisms from TW and ST water samples, respectively. Overall, 66% of the isolates from TW and 38% from ST were resistant to one or more of the drugs tested. Ampicillin, Carbenicillin, Cefalotin and Colistin resistance in particular were more frequent among bacterial isolates. The overall frequency of multiple antibiotic resistance among bacterial isolates in TW and ST samples were 47% and 33%, respectively. All bacterial strains isolated from drinking water were sensitive to Rifampicin. Results demonstrated the need for periodical bacteriological examination of drinking water and restriction in the use of antibiotics in this country.  相似文献   

19.
Munronia delavayi Franch. (Meliaceae) is a vulnerable perennial species that is narrowly distributed and endemic to the dry-hot valley of the middle/lower Jinsha River. However, 12 hydropower stations are currently scheduled to be built in the middle and lower Jinsha River drainage and their distribution overlaps with the range of M. delavayi. The construction of these hydropower stations will cause flooding of the adjacent habitats that support M. delavayi and will change the local ecological environment, which may result in a new and dangerous situation for the survival of this species. Our aim was to evaluate the population structure and propose the most suitable conservation strategy for M. delavayi to support its adaptive potential. In this study, we collected 70 individuals from seven populations that covered most of the geographic range along the Jinsha River and investigated the population diversity, genetic structure and demographic history of this species by analyzing the variations in one mitochondrial marker (18sf-5sr), two non-coding chloroplast DNA regions (trnT-trnL, trnS-trnG), and one nuclear DNA marker (Gs687f-994r). As a result, three mitotypes, nine chlorotypes and six haplotypes with high genetic diversity (H T = 0.580, 0.774 and 0.740) were detected based on mtDNA, cpDNA and nDNA and a strong genetic structure (F ST = 0.855 and 0.545) was detected based on cpDNA and nDNA. Our study also indicated that habitat fragmentation and limited gene flow may result in the genetic differentiation of this species and that the population distributed in Qiaojia, Yongshan and Panzhihua should be proactively protected based on the conservation genetic analysis.  相似文献   

20.

Purpose

Problems associated with Organochlorine pesticide (OCP)-contaminated soils have received wide attention. To understand the anaerobic biodegradation process constraints, innovative mathematical analysis methods are effective.

Materials and methods

Response surface methodology (RSM) and Tenax TA extraction method combined with the first-three-compartment model were employed to systematically investigate the role of nitrate concentration and bioaccessibility enhancer (methyl-β-cyclodextrin, MCD) in the anaerobic biodegradation of OCPs in contaminated soil.

Results and discussion

The sole addition of either KNO3 or MCD could facilitate the anaerobic biodegradation of OCPs. The highest biodegradation for total OCPs, hexachlorocyclohexanes, endosulfans, and chlordanes were 71.6, 82.1, 68.3, and 55.6 %, respectively, when 20 mM KNO3 and 3.0 % (w/w) MCD were applied simultaneously. As predicted by RSM, the theoretical maximum biodegradation for total OCPs ranged from 60 to 80 % when 20 to 25 mM KNO3 and >2.5 % (w/w) MCD were applied simultaneously. Tenax TA extraction method demonstrated the enhancement of OCP bioaccessibility caused by MCD addition. Changes in the soil microbial activities also suggested the positive effects of adding suitable amounts of KNO3 as a cosubstrate to facilitate the anaerobic biodegradation of OCPs.

Conclusions

The amount of KNO3 and MCD are crucial in influencing OCP biodegradation. RSM was demonstrated to be a powerful tool to estimate and predicting the optimal OCP biodegradation under KNO3 and MCD application simultaneously.  相似文献   

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