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1.
Residues of organochlorines and organophosphates were determined by gas chromatography in water and sediment from 26 locations in 17 major rivers, 7 natural springs and 13 wells across Jamaica. Samples were collected on only one occasion between May and July, 1994. Residues of endosulfan were detected in all but three rivers; -endosulfan in 15 samples of sediment (0.9–108.1, mean = 28.93, S.E. = 7.198 g kg-1) and 13 of water (0.01–0.35, mean = 0.11, S.E. = 0.035 g L-1), -endosulfan in 5 sediment (15.29–49.35, mean = 30.56, S.E. = 7.132 g kg-1) and 12 water (0.05–0.31, mean = 0.14, S.E. = 0.031 g L-1) samples, and endosulfan sulphate in waters of three rivers (0.003–0.244 g L-1). Chlorpyrifos was present in 9 sediment (0.423-135.2, mean = 18.38, S.E. = 10.699 g kg-1) and two water (0.001–0.022 g L-1) samples, diazinon and ethoprophos in the sediment of one river each. Mean levels (g L-1) of and isomers and sulphate of endosulfan were 0.16 (S.E. = 0.057), 0.12 (S.E. = 0.036) and 0.15 (S.E. = 0.089), respectively, in four of the seven springs and 0.23 (S.E. = 0.052), 0.11 (S.E. = 0.029) and 0.26 (S.E. = 0.088), respectively, in seven of the thirteen wells monitored.  相似文献   

2.
The difficulty of measuring 15N in dilute solutions has limited the potential of ecosystem labeling experiments and model comparisons. By concentrating the N from large (up to 20 L) water samples on ion-exchange resin columns, we obtained enough N for accurate and reproducible 15N measurement using the Teflon tape diffusion method. Analysis of standards demonstrated >95% recovery of inorganic N from samples, and 15N values comparable to those obtained using standard distillation methods. The value of the blank at our laboratory was 0.16 moles N. Analytical precision was within 2 15N when samples of streamwater from the Bear Brook Watersheds (1800 eq · ha-1 · yr-1 N addition at 192 15N) were kept frozen until analysis. The analytical process is lengthy, but once set up can easily be performed for large numbers of samples.  相似文献   

3.
The adsorption and desorption of three volatile organic compounds (1,2- dichloroethane, 1,1,2- trichloroethane and 1,1,2,2-tetrachloroethane) from a previously uncontaminated clayey soil sample from a Superfund site in North Baton Rouge,Louisiana was studied. In the linear range of the adsorption isotherm, the partition constants were not affected by the presence of the co-solutes. The adsorption isotherms over a wide concentration range on the soil followed the nonlinearFreundlich isotherm. The desorption of the compounds showedsignificant hysteresis at all concentrations studied. Approximately 20 to 70% of the adsorbed mass of organic compounds resisted the desorption even after five months ofsuccessive desorption steps. The desorption of four compounds(1,2-dichloroethane, 1,1,2-trichloroethane, 1,4-dichlorobenzeneand hexachlorobutadiene) from a contaminated soil sample fromthe same site was also studied. The aqueous concentration declined as the successive desorption steps progressed. For hexachlorobutediene the desorption can be visualized as occurring in two stages. The first stage involved a loosely bound or reversible fraction and the second stage involveda tightly bound or resistant fraction.  相似文献   

4.
As all environmental programs also programs monitoring the biotic aspects of our environment (dealt with in this article) should contribute to a more effective and efficient environmental policy. These programs have to function therefore (as no other type of environmental information does, according to the authors) as cheap and efficient early warning and early control systems, providing decision makers with important and reliable monitoring results.How these monitoring programs should function in the decision making process is illustrated in abstract in this article by a simple control system with feedback (as shown in Figures 1, 2 and 3).The monitoring programs dealt with in this article should enable us to detect and forecast changes in the most important biotic aspects of our environment and-by continuous monitoring-to control whether the use of policy instruments has been effective or not in averting or diminishing unwanted changes (problems).Two options of decision makers with respect to monitoring results are shown (either to disregard unwanted changes as a problem or to accept these changes as a problem and to do something about them). To contribute to an effective and efficient environmental policy monitoring results therefore have to be important and reliable enough to react upon.The question is raised which biotic aspects in our environment are (or have to be considered as) important (because of their own value, as indicators and/or as biotic conditions) and how reliable monitoring results can (have to) be obtained.It is discussed how environmentalists could try to make it more difficult for decision makers to duck the problems (by monitoring only important aspects and by using only perfectly clear targets and standards) and how they could try at the same time to make it easier for them to take action (by setting up integrated environmental monitoring programs in order to find out how desired and undesired changes can be influenced). The role of active publicity is stressed in this connection.  相似文献   

5.
An efficient linear Kalman filter has been combined with a coupled atmospheric transport and soil–air exchange model to determine organochlorine pesticides emissions on the regional scale. In this study, results of -HCH emissions from the Great Lakes–St. Lawrence ecosystem, estimated from the coupled model, are presented and discussed. A source receptor technique is used to identify a priori the locations of emission sources of -HCH, the emissions are then updated through a Kalman filtering procedure which minimizes the weighted difference between the predicted mixing ratios from the coupled model and the measured concentrations over the Great Lakes–St. Lawrence river region. Two experiments using the inverse algorithm are carried out. In the first experiment, the coupled atmospheric transport and soil–air exchange model is implemented to predict -HCH air and soil concentrations. Emissions are then updated every 12 days using the updated soil concentrations and emission factors. However, the updated emissions are not input into the coupled atmospheric transport and soil–air exchange model. On the other hand, in the second experiment the updated emissions are fed back to the coupled model, so that the model is reinitialized in each 12 days. The results from the inverse technique for the year 1995 have been compared with grided -HCH emission inventory in Canada, generated by emission factors. It is shown that the estimated emissions of -HCH are consistent with the measured emissions. It is found that the St. Lawrence valley has larger emissions of -HCH than the Great Lakes region, indicating an opposite distribution to the emission usage inventory, but in agreement with the measured -HCH concentration.  相似文献   

6.
Air pollution has been associated with adverse health effects. Difficulties in interpreting studies of health effects of exposure to air pollution arise in estimating exposure. Until recently, studies of effects of air pollution have relied on pollution exposure measurements obtained from fixed location air pollution stations monitoring outside air (to evaluate compliance with air quality standards, rather than to examine population exposure). However, recent evidence suggests that there are substantial differences between air pollution levels measured at such sites and levels to which people are actually exposed, i.e. personal exposure. The present study examines effects of ambient urban air pollution on persons suffering from asthma, healthy non-asthmatic subjects and school children (in 2 Canadian cities, Toronto and Hamilton). Air pollution exposure is being assessed by data obtained from: (1) conventional abatement oriented fixed location air pollution monitoring stations, (2) an extensive population oriented network, (3) inside and (4) outside structures (homes and schools) as well as (5) personal air pollution samplers. The data indicate variability in these different estimates of exposure which have implications on health effects assessment.  相似文献   

7.
Temperature from 12 to 22°C and salinity from 30.5 to 7.6 increased accumulation of copper in Hediste diversicolor. Copper accumulated ranged from 85.83 to 217.14 g g-1. Sediments reduced accumulation of copper under temperature-salinity combinations. Accumulated copper ranged from 90.19 to 153.26 g g-1.However, mortality of the worms was not solely dependent upon copper body-burden. It ranged from 34 to 45% and from 38 to 80% in the presence of sediment. A combination of osmoregulatory and thermal stresses increased the toxic effect of copper to the worms.  相似文献   

8.
The theoretical basis, the content and the possible applications of the program Monitoring of ecosystems are considered. A functional definition of ecosystem is proposed, and some features of ecosystems are defined on this basis. The program Monitoring of ecosystems is visualized as a large-scale program of simple measurements of the rates of the main ecosystem processes. The expected results can be utilized in two ways: (1) a comparative knowledge of ecosystem functioning provides the fundamentals of geography of ecosystems, and (2) the constant, repeatable evaluation of a given ecosystem function provides a basis for its rational management.  相似文献   

9.
The presence of several anthropogenic chemicals has been documented in the atmosphere of the Canadian prairies. The deposition of these chemicals as a mixture is of importancesince little is known of the combined effects of these chemicalson aquatic organisms. This study was designed to evaluate theacute and chronic toxicity of a complex mixture of nineatmospherically transported pesticides to Ceriodaphniadubia. The nine selected pesticides (bromoxynil, dicamba, 2,4-D,MCPA, triallate, trifluralin, pentachlorophenol, lindane, and4,4-DDT) were detected in appreciable quantities in dryatmospheric deposits. The concentration of each pesticide in themixture was based on maximum measured daily dry deposition ratesfor central Canada, except for pentachlorophenol, which wasestimated based on atmospheric concentrations. The 48-h LC50estimate for C. dubia exposed to the pesticide mixture was174.60 g L-1 (340 times the measured total dry deposition concentration). The estimated NOEC and LOEC for bothsurvival and reproduction, as determined in the 7-d chronic toxicity test, were 51.3 (100 times) and 154 g L-1 (300 times), respectively. A basic risk assessment, using the toxic unit approach, suggested that the toxicity of the pesticide mixture was mainly due to 4,4-DDT. Overall, this atmospherically transported complex mixture of pesticides appearsto pose a negligible toxicological risk to non-target aquatic invertebrates such as zooplankton.  相似文献   

10.
The muscle tissue total mercury (THg) and organomercury (OrHg) concentrations of eel (Anguilla anguilla) and roach (Rutilus rutilis) from the Hg-contaminated River Yare and the uncontaminated Ormesby Broad were compared to their respective bed sediment THg and OrHg concentrations in order to determine if fish in the River Yare had begun to approach 'background' levels. While eel from the Yare had higher flesh concentrations (260 g kg-1) than those from Ormesby Broad (102 g kg- 1), roach were found to have similar concentrations regardless of location (55 and 54 g kg-1 for Yare and Ormesby respectively). However, roach in the Yare had significantly higher body burdens of Hg and organomercury, which when analysed over time (1985–95) showed a decreasing trend approaching the levels observed in fish from Ormesby Broad, suggesting that roach are an overall better biomonitor of contamination then eel. This said, the elevated levels of Hg found in fish from Ormesby Broad indicate the existence of a diffuse source such as atmospheric deposition to the surface waters of East Anglia.  相似文献   

11.
Concentrations of polychlorinated biphenyls (PCBs), DDT and its metabolites, HCH isomers and hexachlorobenzene (HCB) were determined in fish and birds from different locations in the Biobio river basin (central Chile). Samples collected near the mouth of the river contained high concentrations of PCBs, reflecting the massive use of these xenobiotics in the urban and industrial areas of Concepcion and Talcauano. Samples collected in the central part of the basin contained very high concentrations of lindane that coincide with the widespread use of lindane-based pesticides (purified -HCH) in this area. DDT was distributed homogeneously throughout the basin, except at Laguna Icalma, the source of the river in the Andes. Most PCB residues in fish and birds consisted of congeners between penta- and hepta-chlorobiphenyls. In fish, the predominant congeners were the pentachlorobiphenyl 23445 (IUPAC number 118) and the hexachlorobiphenyl 2234455 (PCB-153); in birds 224455 (PCB-180) prevailed.  相似文献   

12.
Aldehydes are an airborne byproduct of many industrialprocesses, vehicle transportation, and emissions fromnumerous natural sources. To characterize aldehydeconcentrations in ambient air of the Savannah, Georgiaarea, air samples for 3 aldehydes (formaldehyde,acetaldehyde, and propionaldehyde) were collected atfive sites on a monthly basis over a 12-month periodfrom December of 1995 through November 1996. Four ofthe sites were in central Savannah and the fifth sitewas located in a rural area about 56 km south ofSavannah. During each 24-hr sampling episode, sampleswere collected in two 12-hr periods approximatingdaylight and nighttime hours, following U.S. EPAMethod TO-11. Formaldehyde concentrations ranged from0.17 to 6.80 g m-3, acetaldehydeconcentrations ranged from 0.07 to7.60 g m-3, and propionaldehyde levels rangedfrom 0.02 to 9.10 g m-3. On average, thefour sites in Savannah had higher aldehydeconcentrations than the rural site (2.0 versus1.2 g m-3 for formaldehyde, 2.3 versus1.7 g m-3 for acetaldehyde, and 1.2 versus1.0 g m-3 for propionaldehyde). The daytimeconcentrations for formaldehyde and acetaldehyde werehigher than the nighttime levels. The data from allthe sites were within published worldwide backgroundvalues for aldehydes.  相似文献   

13.
The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 g L-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 g L-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 g g-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 g g-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin.  相似文献   

14.
A one-year study was conducted on the chloroform concentrationof the municipal drinking water of Hyderabad City. Consumertap water samples were collected from different parts of thewater-distribution system of the city. Duplicate samplescollected from the sites were extracted with organic solvent,pentane and analysed using a gas chromatograph equipped with63Ni electron capture detector. Results indicate avariation in haloform concentration in different seasons ofthe year. A maximum concentration, ranging from 67.0–70.5g/l was observed during the summer. However, the meanlevel of chloroform was below the permissible level of 30g/l recommended by WHO (1984).  相似文献   

15.
The simultaneous behaviour of seven ecological indices(Hurlberts, Margalefs, Menhinicks, Shannons,species number, Jaccards and saprobic index) wasstudied based on phytoplankton data close to the shoreon the East coast of Sweden during the summer 1998.The sampling stations had a similar eutrophicationlevel and were located in bays. Standard phytoplanktondatabases were used in calculating the indices, whichwere later compared using cluster analysis.Hurlberts, Margalefs, Menhinicks, Shannons andspecies number indices, as measure of communitydiversity, produced similar trends which oftendiffered from those based on Jaccards index ofsimilarity. However, the simultaneous use of theseindices was found meaningful as a possible part of themonitoring close to the shore. The application of asaprobic index lead to erroneous conclusions in thestudied case.  相似文献   

16.
Heavy metal concentrations in Hylocomium splendens collected around a metal smelter in Latvia showed very high concentrations of Zn (>200 g/g), and elevated concentrations of Pb (38.3 g/g) and Cu (18.3 g/g). In an attempt to better evaluate the potential toxicity of the high Zn concentrations, a serial elution method was used to determine the concentrations of zinc in intercellular, extracellular exchangeable cell wall, intracellular, and particle fractions. The intercellular Zn concentrations represent the water soluble component of the total concentrations, and were low with no clear trends. Zn concentrations in the extra- and intracellular and particle fractions decreased exponentially from the pollutant source. Intracellular Zn concentrations in moss close to the emission source are within the range considered to be potentially toxic, from other single element exposure studies. The proportion of Zn in the relatively insoluble particle fraction, which is least associated with environmental risk, was greater closer to the pollution source, reaching > 30% in the oldest Hylocomium splendens segments.  相似文献   

17.
A sensitive method for sequential determination of V, Mn, Fe, Co, Ni, Cu, Zn, Mo and Sb in sea water using an inductively coupled plasma mass spectrometry (ICP-MS) after electrothermal vaporization of their dithiocarbamate complexes in methyl isobutyl ketone (MIBK) has been investigated. All analyte elements were simultaneously concentrated 20 fold in a single extract and introduced into the plasma using a graphite rod electrothermal vaporizer (ETV). A sensitivity enhancement due to a chemical modification using a mixed modifier of palladium nitrate and magnesium nitrate was observed for all analyte elements. The limits of detection of the method ranged from 2 ng l-1 for Co to 329 ng l-1 for V. For the replicate determinations of the analyte elements in a sea water sample, the repeatability was within 10% (as a coefficient variation), except for V (12.8%). The recovery test performed on a sea water sample resulted in values ranging from 87% for Sb to 119% for V. With the exception of Mo, the application of this method for the determination of the analyte elements in sea water samples collected from the surface to the depth of 5000 m at the sampling station of 34°12.08N, 141°57.50E (Oct. 12, 1994) in the northwest Pacific Ocean resulted in vertical distributions and concentration ranges which were in a good agreement with those reported in literatures.  相似文献   

18.
The treated water at the outlet oftreatment plants and representative servicereservoirs of Mumbai city have been evaluatedfor trihalomethane formation potential in1995–1996. Chloroform, dichlorobromomethane,chlorodibromomethane and bromoform have beenmonitored during monsoon, winter and summer.The levels of chloroform are found above theregulated WHO guideline value of 200 g L-1 in final water during postmonsoon atGhatkopar (226 g L-1), Malbar (210.3 g L-1) and Tulsi (231.26 g L-1).  相似文献   

19.
Although exposure assessments cannot be completed remotely, remote sensing techniques provide an invaluable adjunct in exposure monitoring programs. Exposure can be defined as the summation over time, in all media, of the amount of a pollutant available at the exchange boundaries of the receptor during a specified period. This paper describes a few remote monitoring techniques that provide direct measurement input into an exposure assessment and several that furnish quantitative or qualitative information leading to decisions regarding how to monitor, such that the source-exposure-dose relationships can be fully defined. Two general classes of remote sensing systems are included in this discussion-passive and active. Passive systems depend on a measurement of the energy reflected or emitted by a target and active systems use an energy source, e.g., a laser to perform the environmental interrogation. Airborne as well as ground-based remote monitoring measurements or systems are also considered in this paper.  相似文献   

20.
On the Kola Peninsula, the mining and concentration industry exerts anthropogenic impact on the environment. Tailing dumps cause airborne pollution through dusting, and waterborne pollution due to direct dumping and accidental releases. The objectives were: (1) to analyse multidate satellite imagesfor 1964–1996 to assess the environmental pollution from themining and concentration activity in the Kola in temporal perspective; (2) to evaluate remote sensing methods for integrated environmental impact assessment. The area of mining and industrial sites steadily expands and amounted to 94 km2 in 1996. The polluted water surface amounted to at least 150 km2 through dumping in 1978 and to 106 km2 in1986 due to dusting. Thus, the impact from the mining and concentration activity should be reconsidered as more significant than it was officially anticipated. In the past the main mechanism of pollution wasdirect dumping into the lakes. Currently and in future, airborne pollution after dusting storms will dominate. The effective recultivation of the tailing dumps will be a long-term process. For effective assessment of impacts from the mining and concentration industry, remote sensing methods should be complemented by in-situ measurements, fieldwork, and mathematical modelling.  相似文献   

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