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1.
During the period 1977–1980 we studied the effects of highly acidic precipitation (mean pH 4.1 to 4.2) on the chemistry of three Adirondack lakes: Woods Lake, Panther Lake, and Sagamore Lake. Two of these lakes (Woods and Panther) are enough like those lakes of southern Sweden and Norway studied by Henriksen that they should constitute a valid test of his ‘acidification indicator’ and ‘predictor homograph’. In our comparison we used data from weekly samples taken near the surface of the lakes during unstratified summer and fall conditions over a 3 yr period. The acidification indicator and predictor nomograph were developed using data from lake samples taken under similar conditions in Scandinavia. Our principal finding is that with regard to the empirical line of the acidification indicator (that Henriksen found separated data from lakes receiving precipitation greater or less than pH 4.6) and with the precipitation pH axis of the predictor nomograph, these two methods of evaluation are not directly applicable ‘as is’ to our lakes. The reason for this is that the chemistry of precipitation in the Adirondacks is significantly different from (and for) which the acidification indicator and predictor nomograph were developed. In the Adirondacks, acids other than H2SO4 play a much greater role in the overall acidity of the precipitation. This causes relationships between precipitation pH and lake chemistry in the two regions to be different.  相似文献   

2.
Nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) were compared for their ability to solubilize Pb from a highly-contaminated (PbT 21%) soil collected from a battery recycling facility. For chelant concentrations below 0.04 M (representing a 1:1 chelant-to-PbT molar ratio), EDTA released 10 to 30% more Pb than NTA. NTA-to-Pb T ratios greater than 1:1 reduced Pb recovery because of readsorption of Pb(NTA)2 4? onto positively-charged oxide soil components at pH < 8.5. For the EDTA system, however, complexation completely bound all coordination sites of Pb and EDTA, leaving no functional groups available for surface adsorption. Thus, Pb recovery progressively increased with higher EDTA concentrations, although the additional Pb release with each EDTA increment became smaller. For pH < 5 and EDTA/Pb of 2:1, Pb recovery exceeded 90%. The addition of 0.5 M NaC1O4 enhanced Pb recovery by EDTA for pH 5 to 12, but substantially suppressed recovery by NTA for pH < 11. Because Pb release by NTA was diminished by high ionic strength and chelant-to-metal ratios, NTA may be limited as a soil washing reagent. Stronger complexation and consistent Pb desorption behavior by EDTA favors its use.  相似文献   

3.
Sediment cores were taken from the remote Sagamore and Woods Lakes in New York State's Adirondack acid lake region and analyzed for 3 to 7 ring polycyclic aromatic hydrocarbons (PAHs) and Ag, Al, As, Be, Cd, Cr, Cu, Hg, Ni, Ph, Se, Sn, TI, V, and Zn. With the exception of perylene, all of the parental PAHs, e.g. those without sidechains, and several of the metals, Pb, As, and Cd, were found to be significantly increased in the sediments of both lakes compared to their natural integrated deposits (ng cm?2) and their background concentrations (μg g?1 or ng g?1 dry wt). Although the concentrations were generally much higher in Woods Lake, the total anthropogenic integrated depositions were about the same in both lakes for most of the metals and the 3 to 4 ring PAHs. The prime source of most of the 3 to 7 ring PAHs and trace elements measured is ascribed to anthropogenic combustion. Anthropogenically derived materials decreased in concentration with depth to baseline levels in sediment layers estimated by137Cs analyses to be ~30 yr old, while biogenic or crustal derived species remained constant or fluctuated with core depth.  相似文献   

4.
A theoretical model describing the general interaction between atmospheric trace gases, such as S02, NH3, C02 and 02, chemical reactant gaseous product H2SO4 and hydrometeors containing NaCl is proposed to study a possible mechanism for HCl production in non-precipitating cloud and the determination of the pH value of cloud droplets. Four different cloud droplet distributions have been used to estimate the upper limit of the amount of gaseous HCl released into the atmosphere resulting from the evaporation of cloud droplets. It is shown that the acid production and the amount of HCl released depend on the following factors: (a) the temperature of the cloud; (b) the oxidation rates; (c) the ambient concentration of SO2, NH3, and H2SO4; (d) the life cycle of the cloud; and (e) the liquid content of the cloud. This proposed chemical model also predicts a pH value spectrum depending on the cloud droplet distribution. Field measurements for the dependence of pH value on particle size and spatial distribution of gaseous HCl are recommended.  相似文献   

5.
A national and interregional programming model is analyzing the effects of banning Chlordane and Heptachlor from U.S. agriculture. The model has sectors for land and water resources, crop and livestock production, commodity transportation and domestic and foreign demand. The central Corn Belt would be put at some disadvantage and lose production to other regions. Soybeans and small grains would replace corn on low lands and the imputed values of this land would decline. Crop rotations would include somewhat less corn.  相似文献   

6.
The objectives of this study were to determine and to reduce phytotoxicity of two industrial effluents. Phytotoxicity of the treated and untreated samples was determined using millet seed germination test. The results of this and other studies showed that the test was reproducible and useful for effluent toxicity determination. Effluent sample I was from an industrial wastewater pretreatment plant and sample II was from a specialty chemical industry. Sample I was weakly acidic and sample II was alkaline. pH adjusted to 7 to 8 was found to have no effect in phytotoxin removal. Granular and powdered activated carbon effectively reduced phytotoxicity. Amberlite XAD-4 (nonionic polymeric adsorbent) and cation exchange resin had a partial effect. Anion exchange resin, silica gel, Sephadex G-75, and starch xanthate had no effect.  相似文献   

7.
The specific conductance of surface delivery waters to the Shark River Slough (Everglades National Park, Florida) has increased significantly since the completion of Levee 29 (L-29) and the S-12 water delivery system in the early 1960's. In order to document the response of specific conductance in the slough to changing environmental conditions, it was monitored continuously for a period of 12 mo at a location in central Shark approximately 17 km south of the water delivery site. In addition, variability in isoconductivity patterns throughout the slough was assessed by conducting biweekly surveys at 97 locations. Specific conductance was found to respond to a variety of natural and manmade environmental changes and proved to be an important management tool serving as an early indicator of potentially broad changes in water quality. Factors important in determining overall isoconductivity patterns in Shark Slough include:
  1. the ionic composition of surface delivered to Shark Slough via the S-12 delivery structures.
  2. the quantitative relationship between the amount of surface water delivered to the slough and the amount of precipitation falling directly upon the slough.
  3. the effects of evapotranspiration and concentration of biological organisms during seasonal periods of extreme drawdown.
  相似文献   

8.
A study has been conducted on the transformation of Cr(III) and Cr(VI) in simulated natural water conditions. It has been found that these forms are readily interconvertible under natural water conditions. The results of this study indicate that Cr(VI) is reduced by Fe(II), dissolved sulfides, and certain organic compounds with sulfhydryl groups, while Cr(III) is oxidized by a large excess of MnO2 and at a slow rate by Oz under conditions approximating those in natural waters. Based on the results of these studies, water quality standards for Cr should be based on total Cr rather than on Cr(VI), as has been frequently done in the past.  相似文献   

9.
Management of soils to facilitate plant beneficial microbial interactions requires basic knowledge of the species composition and microbial community structures in the plant rhizosphere. Here, we examined composition of bacterial communities associated with rhizosphere microsites located at the root tips and mature root zones of Lolium perenne when grown in Chilean ash-derived volcanic soils (Andisols: Freire and Piedras Negras soil series). Community structures were analyzed by pyrosequencing of 16S ribosomal RNA (rRNA) genes followed by in silico analysis for phylogenetic assignments (MOTHUR and Visualization tool for Taxonomic Compositions of Microbial Community (VITCOMIC)). Analysis of the community structure revealed significant differences in community structures in relation to the soil series, which differed particularly in the relative abundance of Cyanobacteria and Firmicutes. However, no significant differences were observed with respect to root microsite location in the same Andisol series. Predominant taxa included members of the Proteobacteria, Actinobacteria, and Acidobacteria. Analysis by VITCOMIC showed that dominant bacterial groups comprised only 5 to 10 % of the total bacterial community and the remaining majority of bacteria included low-abundant taxa (Fusobacteria, Thermotogae, Lentisphaerae, Tenericutes, Deferribacteres Spirochaetes, Planctomycetes, Thermotogae, and Deinococcus-Thermus), most of which have not been previously reported or associated with the plant rhizosphere according to GenBank database. The results indicate that most of bacteria in the Chilean Andisols have not been described to the rhizosphere plants and their functional traits are still largely unknown.  相似文献   

10.
The control efficiency, concentration of particulate matter and emission rate of particulate matter were determined from a municipal incinerator equipped with an electrostatic precipitator. An EPA and a modified ASME-ASTM particulate matter sampling train were used concurrently at precipitator inlet and outlet sampling ports to confirm the manufacturer's guarantee of collection efficiency and to determine compliance with local emission regulations. A comparison of the weight of particulate matter collected during 22 test runs with each type of sampling train indicated that an out-of-stack filter in the current arrangement of the ASME-ASTM train results in a particulate matter catch which is comparable to that from the front portion of the EPA train. A statistical Mest performed on the particulate matter catch from both sampling trains indicates no significance in the difference of the mean catch values of both the front portion and the combined front and back portions of the sampling trains. Doubt is cast upon previous assertions that differences in the particulate matter caught by the two sampling trains are caused by the condensation of sulfur oxides and organic vapors within the back half of the EPA train. Rather, it appears that there is a loss of particulate matter from the Alundum thimble of the ASME-ASTM train that can be caught by a fiber glass out-of-stack filter.  相似文献   

11.
The antifoulant agents, bis-(tributyltin) oxide (TBTO), tributyltin acetate (TBTOAc) and tributyltin chloride (TBTCI) were mixed with various media. These media included distilled water, seawater, aerobic and anaerobic sediments. The Mossbauer spectra of the chloroform extracts of the distilled water and seawater mixed with these compounds were examined. The componds were mixed with aerobic and anaerobic sediments, and the Mossbauer spectra of the sediments were also examined. TBTO was converted to the hydroxide compound in all media except in anaerobic sediment where it was converted to an unidentified compound. TBTOAc and TBTCI were not changed by mixing with distilled water and aerobic sediment but were converted to the hydroxide compound in seawater and in anaerobic sediment.  相似文献   

12.
The effect of six organic amendments on Pb solubility and availability was studied from May to September 1978 in a sandy soil low in organic matter. Three extractants were used to essay the Pb solubility: BaCl2 0.5M, AcNH4 2.5% at pH 7.0 and EDTA 0.05M at pH 7.0. During the aging process both increases and decreases of Pb solubility were observed in manured soils with respect to the control. Only in the soil treated with cow manure was a decrease of Pb solubility in ammonium acetate always noted. From regression lines of Pb concentration on soil/solution ratio it was possible to observe that only the soil treated with cow manure showed a significant decrease of slope of regression line when it was dispersed in ammonium acetate solution. The regression lines of Pb concentration on organic matter extracted by ammonium acetate and, especially, EDTA showed that these reagents extract mainly Pb complexed with organic compounds. A physiological test on Pb availability showed that only in the presence of cow manure was the Pb assimilation greatly decreased.  相似文献   

13.
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   

14.
We examined the effect of TiO2 nanoparticles (NPs) on the growth of maize and soybean plants and associated soil microbial communities. Plants were grown in a greenhouse, and low levels of undoped or nitrogen-doped TiO2 NPs were applied. Plant growth and nutrient content were determined, and effects of NPs on composition of soil microbial communities were examined using terminal restriction fragment length polymorphism analysis (TRFLP) of rDNA. We found no significant effects of TiO2 NPs on plant growth, nutrient content, or the composition of bacterial communities within the rhizosphere. However, arbuscular mycorrhizal fungal communities were affected by application of undoped and nitrogen-doped TiO2 NPs. This observation may be partially attributed to the small but significant TiO2 NP uptake levels in the root tissues of both plants. Our results suggest that even low concentrations of TiO2 NPs may influence some important groups of soil microbes, such as mycorrhizal fungi, but changes in the composition of microbial communities may not affect plant growth under conditions of adequate moisture and nutrients.  相似文献   

15.
The coastal dune aquifer, providing drinking water for a large part of the population of the western Netherlands, is recharged by fainfall and artificial infiltration of Rhine water. Chernobyl fall-out has been detected in both water sources. At the Castricum lysimeter station the rainfall-derived water, draining from 2.25 m of unsaturated sandy soil, shows levels of Cs-137 around the detection limit of 20 to 40 mBq kg?1. At this site, the soil itself retained some Chernobyl-derived Cs-137 in the top 10 cm, where a similar quantity of old Cs-137 has also been retained. Penetration of old Cs-137 is deeper (up to 70 cm) under oak vegetation than in the bare soil. In the infiltration channels, fed by Rhine water, the bottom mud contains only Chernobyl-derived Cs nuclides. Radioactivity from Cs-137 is about one tenth of that from natural radioactivity due to K-40. Cesium levels are apparently unrelated to adsorptive properties.  相似文献   

16.
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   

17.
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   

18.
Experimental exposure to Cr(VI) induced anomalies in the peripheral blood and tissues of a freshwater fish, Barbus conchonius. Clinical findings in the blood corpuscles included swelling of erythrocytes, numerous circulating polychromatophils, and vacuolation of large lymphocytes during acute exposure. Poikilocytosis, severe cytoplasmic vacuolation and deterioration of cytoplasmic membrane in erythrocytes occurred following chronic exposure. Significant polycythemia with collateral rise in Hb and Hct were manifest in the acutely intoxicated fish. By contrast, chronic exposure caused marked erythropenia and an accompanying reduction in Hb and Hct values. Leucocyte subpopulations showed an initial rise and then a fall in the thrombocytes together with a significant lymphocytosis, neutropenia, and basophilia. Pathological changes were observed in the gills, kidneys, and liver of Cr-exposed fish.  相似文献   

19.
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   

20.
The effect of three herbicides (Linuron, Diuron, and Atrazine) and three vinyl phosphate insecticides (Crotoxyphos, Phosphamidon, and Dichlorvos) on phytase was examined. All the insecticides and Atrazine were competitive inhibitors, with Linuron and Diuron being mixed inhibitors. Some implications of phytase inhibition on inorganic P availability in soil are discussed.  相似文献   

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