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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.
A field study designed to determine the nature and extent of environmental impact by an industrial complex was carried out during the period 1966–76. The industrial complex consists of two oil refineries, Mobil and Atlantic Richfield (ARCO), and an aluminium reduction plant, Intalco. The location is northwestern Whatcom County, Washington, U.S.A. The study consisted of critical examination of native, exotic, and cultivated plants in 75 sites; productivity analysis at two sites; plant community analysis at three sites; total-S analysis of leaves at 37 sites; and soil S analysis at 10 sites. The effect of SO2 emission by Mobil and ARCO appeared to be negligible, except in regard to injury to lichens and bryophytes; however S accumulation was strongly correlated with distance from the refineries, wind pattern, and ambient air concentrations of SO2. Hydrogen fluoride is an established pollutant from Intalco and is thought to have reacted synergistically with SO2 to produce injury symptoms at S concentrations below reported injury threshold levels.  相似文献   

3.
High levels of ozone and acidic fog have been measured along the coast of Maine, U.S.A. Some of the ozone and nitrate are a consequence of direct transport from East Coast metropolitan centers, but we discuss evidence supporting N2O5, and perhaps ozone, generation at forested sites from NOx precursors. Fogs with pH below 3.3 occur with greatest frequency in the mid-coast region. Ozone is consistently highest along the southwest coast, but peak hourly averages are often highest in the mid-coast. Historical evidence suggests an increase in fog acidity and nitrate levels, but no change in sulphate within the past 48 years. Red spruce with decline symptoms can be observed from the south-coast to mid-coast region, with the greatest symptom development in the mid-coast. Trees in the mid-coast on soils with high base saturation and Ca/Al ratios develop symptoms of late winter injury (reddening and casting of current year needles in late winter and spring). Trees on poorer soils develop chlorosis on upper surfaces of older needles. Nutrient analysis of soils and foliage reveals differences between stressed and unstressed sites. Scanning electron microscopy of needle surfaces also reveals response differences between pollutant stressed and unstressed trees. Hypotheses and research directions are discussed.  相似文献   

4.
The application of low-level direct electric current (0.15 mA cm?2) as an electrokinetic technique to treat copper-contaminated mesophilic anaerobic granular sludge was investigated. The sludge was obtained from a full scale UASB reactor treating paper-mill wastewater and was artificially contaminated by Cu(NO3)2 or CuEDTA2? with initial copper concentrations of 1000 mg . kg?1 wet sludge. The effect of different electrokinetic cell layouts, pH and EDTA concentrations on the migration of copper and iron during electrokinetic treatment were evaluated. Both, the pH of the sludge cake or the copper complexation with EDTA significantly affected the migration direction of copper. In an ‘open’ cell (sludge cake in direct contact with air), the highest copper mobility was observed at pH 2.5 in both Cu(NO3)2 or CuEDTA2? amended sludge. The highest copper accumulation was at the cathode (22 ± 2)% with CuEDTA2? as contaminant. In a ‘closed’ cell (sludge cake not in contact with air), the highest accumulation was obtained for CuEDTA2? at the anode and amounted to 4(± 0.5)% and 2(± 0.05)%, respectively, at a final pH of 4.2 and 7.7 in the sludge cake.  相似文献   

5.
Changes in physical, chemical and biological factors were observed during a 5-yr experimental acidification study in Lake 223 of the Experimental Lakes Area, and compared to a 2 yr pre-acidification period. Significant changes included increased transparency, rates of hypolimnion heating and rates of thermocline deepening; increased concentrations of Mn, Na, Zn, Al, and chlorophyll; decreased concentrations of suspended C, total dissolved N, Fe and chloride; increases in Chlorophyta but decreases in Chrysophyta; the disappearance of the opossum shrimpMysis relicta and the fathead minnowPimephales promelas; the appearance of epidemics of the filamentous algaMougeotea; decreased fitness and decline in numbers ofOrconectes virilis; and increased embryonic mortality of the lake troutSalvelinus namaycush. Sulfur budgets for two lakes experimentally acidified with sulfuric acid reveal that an average of 1/4 to 1/3 of added sulfate is sedimented, presumably as FeS, reducing the efficiency of acidification. The sedimentation occurs under both oxic and anoxic conditions. The utility of whole-ecosystem mass balance studies of S in ‘experimental’ and ‘observational’ mass balance studies is discussed.  相似文献   

6.
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   

7.
Raspberry cane disease, caused by a complex of fungi, is amongst the most devastating problems for raspberry production. Using resistant or highly tolerant genotypes is a promising strategy. However, until now, cultivars with good field resistance for German fruit growers as well as the primary causal pathogens of cane disease present in the eastern part of Germany, Saxony state are still unknown. The primary objective of this study was to identify the primary disease causing organisms and resistant Rubus germplasm for future breeding efforts. From 2012 to 2014, we evaluated the degree of susceptibility to cane diseases on 213 raspberry cultivars at two different locations using a rating scale. We also identified the main fungi growing on infected canes. Our results suggest that Fusarium avenaceum is the main fungus causing cane disease in Saxony. The Rubus hybrid cultivars ‘Tayberry’ (2n?=?6x?=?42), ‘Buckingham Tayberry’ (2n?=?6x?=?42) and ‘Dorman Red’ (2n?=?2x?=?14) displayed the highest levels of field resistance at both locations. Moreover, we established an in vitro assay for resistance evaluation which correlates significantly with field data and is particularly suitable for quick assessment of resistance against F. avenaceum in breeding material. Future breeding programs, aiming at cultivars with enhanced resistance towards cane diseases can use the presented data for parental selection and may employ our in vitro F. avenaceum inoculation method for parental testing and progeny selection.  相似文献   

8.
Concentrations of air-borne coliforms and ‘other’ bacteria (defined as total bacteria minus coliforms) were measured. downwind of a sewage treatment plant activated sludge tank. The Gaussian plume diffusion equation adequately predicts concentrations of the ‘other’ bacteria; the diffusion equation must be modified by an extinction coefficient, equivalent to a half-life of about 7.4 s, to predict coliform concentrations. Coliform concentrations downwind of this tank did not present a significant health hazard, but the method is applicable to treatment plants of higher capacity and possibly greater emissions.  相似文献   

9.
A host of chemical industries subject the river to pollutants such as acids, alkalies and their salts, trace metals and radionuclides belonging to the Th and U chains. Proximity of different outfalls and poor lateral mixing in the river are responsible for high local aquatic concentrations. Scavenging reactions, in situ, and sedimentation of suspended matter result in the accumulation of radionuclides near the outfall area. Monsoon ‘flushes out’ the river into the backwater area and translocation of sediments is the major factor in the transport of pollutants.  相似文献   

10.
Abstract

In nutrition experiments of fruit‐growing areas of central Washington state, ‘Delicious’ and ‘Golden Delicious’ apple (Malus domestica) orchards and ‘d'Anjou’ pear (Pyrus communis L.) orchards with the lowest soil pH values had a high incidence of fruit disorders and the lowest concentration of leaf calcium (Ca). In contrast, orchards with the highest soil pH values had the highest concentration of soil Ca (meq 100 g‐1) and the lowest incidence offrait disorders (bitter pit for apples and alfalfa greening, black end and cork spot for pears). Apple orchards with the highest soil pH values also had ‘Delicious’ and ‘Golden Delicious’ apples containing the highest concentration of Ca, but Ca concentrations in ‘d'Anjou’ pears were not significantly different among the different soil pH groups.  相似文献   

11.
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   

12.
The effects of acidic environments on natural Fe oxide rich soils were examined in the laboratory. Experimental evidence indicates that sustained exposure to pH levels within the range of acidic rainfall may cause substantial changes in the physical/chemical properties of these soils. The significant effect observed was the decrease in magnitude or the reversal of the electrical potential exhibited. For example, the zero point of charge shifted from a pH of 1.5 for the unamended soil to a pH of 8.8 as the soil was aged in the lowest pH solution (pH 1.0). The adsorption of `free' and complexed heavy metal ions (Zn and Zn-EDTA) increased significantly due to acid aging and it is proposed that increased weathering of Fe due to acidic rainfall will accelerate the natural podzolization process. Generally, soils not exposed to acidic conditions tended to behave in a ‘clay-like’ manner while those soils aged in an acidic environment tended increasingly toward an Fe hydroxide/oxide behavior as the pH level of soil exposure was decreased.  相似文献   

13.
There is growing concern that air pollution may have adverse impacts on crops in developing countries, yet this has been little studied. This paper addresses this issue, for a major leguminous crop of the Indian sub continent, examining the effect of air pollution in and around an Indian city. A field study was conducted using a gradient approach to elucidate the impact of air pollutants on selected production characteristics of Vigna radiata L. cv. Malviya Jyoti (mung bean) plants grown from germination to maturity at locations with differing concentrations of air pollutants around peri-urban and rural areas of Varanasi. The 6 -h daily mean SO2, NO2 and O3 concentrations varied from 8.05 to 32.2 ppb, 11.7 to 80.1 ppb and 9.7 to 58.5 ppb, respectively, between the sites. Microclimatic conditions did not vary significantly between the sites. Changes in plant performance at different sites were evaluated with reference to ambient air quality status. Reductions in biomass accumulation and seed yields were highest at the site experiencing highest concentrations of all three gaseous pollutants. The magnitude of response indicated that at peri-urban sites SO2, NO2 and O3 were all contributing to these effects, whereas at rural sites NO2 and O3 combinations appeared to have more influence. The quality of seed was also found to be negatively influenced by the ambient levels of pollutants. It is concluded that the air pollution regime of Varanasi City causes a major threat to mung bean plants, both in terms of yield and crop quality, with serious implications for the nutrition of the urban poor.  相似文献   

14.
The U.S. Environmental Protection Agency (EPA) designated 20 urban areas including major cities located in mid-Atlantic US area as being in non-attainment of the new national ambient air quality standards for PM2.5 (particulate matter ≤2.5 μm in aerodynamic diameter). To support the development of effective State Implementation Plans for PM2.5 in the non-attainment area, 24-h integrated Speciation Trends Networks data collected in the mid-Atlantic US urban area were analyzed through the application of the positive matrix factorization (PMF). A total of 117 to 235 samples and 27 to 29 chemical species collected at the four monitoring sites between 2001 and 2003 were analyzed and six to nine sources were identified. Secondary particles provided the highest contributions to PM2.5 mass concentrations (38–50% for secondary sulfate; 9–18% for secondary nitrate). Potential source contribution function analyses show the potential source areas and pathways of secondary particles contributing to this region, especially the regional influences of the biogenic as well as anthropogenic secondary particles. Motor vehicle emissions contributed 21–33% to the PM2.5 mass concentration. In four sites in southern New Jersey and Delaware, gasoline vehicle and diesel emissions were tentatively separated by different abundances of organic and elemental carbons. The compositional profiles for gasoline vehicle and diesel emissions are similar across this area. In addition, other combustion sources, aged sea salt, and intercontinental dust storms were identified.  相似文献   

15.
Six-week-old rooted cuttings of Populus nigra L. ‘LOENEN’ and Populus maximowiczii Henri X Populus nigra L. ‘ROCHESTER’, differing in their phenomenological sensitivity to O3, were submitted to low concentrations of O3, NOx, and SO2. Exposure was performed in open top-chambers from 25.5. until 6.7.1988. Comparing the response of the two poplars by 77 biochemical criteria the macroscopic O3- sensitivity of ‘LOENEN’ was clearly reflected in changes of the pool sizes of the different nonstructural carbohydrates, polyols, and phenolics of the leaf-lamina, petiole, shoot-axis, and roots. In contrast, both varieties revealed the same response to NOx/SO2-mixtures. It can be concluded that ‘LOENEN’ together with ‘ROCHESTER’-poplars as controls, are an appropriate system to specifically indicate O3 in a mixture of air pollutants.  相似文献   

16.
The Hg concentrations in coal as fired in power plants in the Netherlands are low, 0.2 mg·kg?1 on average. After combustion the Hg is released partly (between 1 and 98%, on average 42%) in a gaseous phase, which is finally emitted into the air. The other part of the Hg, which remains in the ash is separated from the flue gases by electrostatic precipitators. The variation of the vaporisation percentage of Hg is probably caused by the presence of two chemical forms: Hgo and HgCl2. This may be concluded from the observation that relatively high concentrations of HCl in the flue gases (≈150 mg·m?3) give rise to low Hg concentration in the vapor phase. In cases when the concentrations of HCl are relatively low (≈25 mg·m?3) the amount of Hg in the vapor phase is high. The average gas phase concentrations of Hg in the flue gases, based on 33 measurements with no FGD, is 4.1 μg·mfo ?3. In a wet FGD based on the lime/limestone-gypsum process 50 to 70% of the Hg in the flue gases is removed, leaving a residual concentration of 1–2 μg·mfo ?3. The emission factor is then about 0.5 mg·GJ?1 or 5 μg·kWhr?1. In one particular measuring serie the fate of Hg was studied in a FGD-installation with a prescrubber.  相似文献   

17.
This paper discusses the results of the air quality monitoring activities, especially for three of the Ontario Ministry of the Environment's criteria pollutants (SO2, O3, and total suspended particulates). In the early 1960's Nanticoke Hamlet, located on the northern shore of Lake Erie, was selected for a large industrial development program. The first phase saw the commissioning of a 4000 MW Ontario Hydrothermal generating station, a 100 000 bbl day?1 Texaco refinery and a Stelco steel plant with an initial annual capacity of 1.7 × 106 tonnes. Favorable climatological data was one of the criteria used for selecting this site. Extensive monitoring of ambient air and water quality was carried out prior to the construction phase of the program. Post operation monitoring has also been done on a continuous basis. The data collected to date indicate that the impact of the industrial activity on air quality in the Haldimand-Norfolk region has been very small, with less than 20 exceedances per year of the hourly air quality criterion for SO2 (250 ppb) being observed across the network, and total suspended particulates being similar to other rural locations in Ontario. Only 03 has a substantial number of exceedances of the criterion (80 ppb hourly average) during the summer months, primarily due to long-range transport into the area from across Lake Erie.  相似文献   

18.
Rain and snow were collected in plastic beakers either manually or with a Wong sampler during 58 precipitation events in 1974 at Yonkers, New York approximately 24 km north of the center of New York City. Determinations were made of total dissolved ionic species, free H ions, total H ions, sulfate, nitrate, chloride, and fluoride. Conductivity measurements ranged from 6.8 to 162 gmhos, pH from 3.4 to 4.9, total acidity from 36 to 557 μeq 1?1 sulfate from less than 1 to 20 mg 1?1, nitrate from less than 1 to 14 mg 1?1, and chloride from less than 1 to 7 mg 1?1. All fluoride concentrations were less than 0.1 mg 1?1. The results indicate that precipitation at this suburban location adjacent to New York City is consistently acidic and contains concentrations of sulfate, nitrate, and chloride which are similar to values found for other locations in the northeastern United States. Positive correlations were found between nitrate and sulfate concentrations and acidity suggesting that the atmospheric contaminants, SO2, and NO2 are causally-related to the occurrence of acidic precipitation. Further research will be necessary to clarify the relative influence of natural and man-made sources of N and S compounds and the contributions of gaseous and particulate contaminants in the atmosphere to the acidity of precipitation at this location.  相似文献   

19.
Precipitation chemistry at sinhagad-a hill station in India   总被引:1,自引:0,他引:1  
The chemistry of precipitation in remote sites such as mountain tops is of interest in the study of atmospheric pollution and acid rain. The chemical composition measured at mountain site which is away from industrial and urban areas is useful as a reference level and it allows to determine the extent of anthropogenic contamination. Hence, rain water samples were collected at Sinhagad (18°21N, 73°45E, 1450 m asl during the monsoon season (June-September) of 1992 and were analysed for major ions. The precipitation samples collected at Sinhagad were alkaline in nature and pH values ranged between 5.9 to 6.76. The ionic composition was dominated by soil dust The concentration of Ca2+ was highest among all the ions. The concentrations of excess SO3 2– and NO4 were small (23.8 and 15.2 eq l–1 respectively) compared to the values of polluted regions in India. The correlation coefficient between the ions and pH values was calculated and it was found to be maximum in case of Ca2+. Precipitation samples collected at Sinhagad were alkaline owing to higher concentration of Ca2+ and lower levels of acidic pollutants (SO4 2– and NO3 ).  相似文献   

20.
Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed in greenhouse or field to simulated rain of pH 3.2 ± 0.1 or pH 6.0 ± 0.2. Simulated ‘rain’ of pH 3.2 resulted in: (1) an 86% inhibition in telia production of Cronartium fusiforme on Quercus phellos; (2) a 66% inhibition of reproduction of Meloidogyne hapla on field-grown Phaseolus vulgaris; (3) a 10% decrease in the severity of Uromyces phaseoli on field-grown Phaseolus vulgaris; and (4) an inhibition of Rhizobium nodulation of Phaseolus vulgaris and Glycine max by an average of 73%. Effects on halo blight of kidney bean (caused by Pseudomonas phaseolicola) depended upon the segment of the disease cycle in which the ‘rain’ occurred: (a) simulated rain of pH 3.2 applied to plants before inoculation stimulated disease development; (b) suspension of inoculum in ‘rain’ of pH 3.2 decreased inoculum potential; and (c) ‘rain’ of pH 3.2 applied to plants after infection inhibited disease development. Scanning electron microscopy of epicuticular waxes on leaves of Quercus phellos and Phaseolus vulgaris showed marked erosion of those surfaces by ‘rain’ of pH 3.2, indicating possible influences on the structure and function of plant cuticles. These results suggest that the acidity of rain is a new parameter of environmental concern, and underline the need for study of the consequences of prolonged exposure of both agronomic and natural ecosystems to this stress factor.  相似文献   

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