Showing papers in "Environmental Science & Technology in 1970"
TL;DR: In this article, it was shown that high CONCENTRATIONS of one METAL in the soil do not NECESSARILY degrade with distance from the road with other METALS.
Abstract: MOTOR VEHICLES CONTAMINATE ROADSIDE SOILS AND VEGETATION WITH FOUR HEAVY METAL ATMOSPHERIC POLLUTANTS. THE CONTAMINATION HAS BEEN CORRELATED WITH COMPOSITION OF GASOLINE, MOTOR OIL, AND CAR TIRES. THESE CONCENTRATIONS DECREASE WITH DISTANCE FROM TRAFFIC AND WITH DEPTH IN SOIL PROFILE. IN SPITE OF THE DEPENDENCE OF ROADSIDE CADMIUM, NICKEL, LEAD, AND ZINC ON TRAFFIC, IT APPEARS THAT HIGH CONCENTRATIONS OF ONE METAL IN THE SOIL DO NOT NECESSARILY ENTAIL HIGH CONCENTRATIONS OF ANOTHER ONE OF THE METALS. /AUTHOR/
521 citations
511 citations
TL;DR: In this paper, soil and plants were sampled along heavily traveled highways and lead contents tend to increase with traffic volume and decrease with distance from the highway and the major effect of traffic was limited to the surface soil and to a narrow zone within 100 feet of the highway.
Abstract: Soils and plants sampled along heavily traveled highways show that lead contents tend to increase with traffic volume and decrease with distance from the highway. Much of the lead was present as a removable surface contamination on the plants. The major effect of traffic was limited to the surface soil and to a narrow zone within 100 feet of the highway. Plants grown in the field contained the most lead in the aerial portion and those grown in the greenhouse had the most lead in the roots. These studies indicate plants may obtain lead through both leaves and roots with little translocation within the plant. The fruiting and flowering parts of plants contained the smallest amounts of lead and showed little effect of changes in amounts of lead supplied. 19 references, 1 figure, 5 tables.
298 citations
TL;DR: In this article, the rate and extent of algal degradation under simulated natural conditions were evaluated under dark, anaerobic, constant-temperature laboratory conditions, and effects of high sulfate concentration, bacterial seedings, temperature, pH, and cell composition were evaluated.
Abstract: The major objective was to determine the rate and extent of algal degradation under simulated natural conditions. Decomposition of heterogeneous and unialgal cultures was studied under dark, anaerobic, constant-temperature laboratory conditions. Effects of high sulfate concentration, bacterial seedings, temperature, pH, and cell composition on the rate and extent of degradation were evaluated. After 200 days, decomposition of algal cultures was essentially complete, and the undecomposed particulate organic matter remaining was termed the refractory organic fraction. This fraction ranged from 20 to 60% of the ash-free dry weight for various culture with an average of 40%. The decomposition of the biodegradable organic fraction could be adequately described by first-order decay kinetics with a range for the decay constant k of 0.011-0.032/d with an average 0.022/day. The rate and extent of degradation were similar to those found by other investigators under aerobic decomposition conditions.
196 citations
TL;DR: In this article, the authors found significant differences in the lead isotope ratios in rock and soil, grasses, tree leaves and tree rings, air particulate, and in some industrial products such as coal, fly ash, gasoline, and fuel oil.
Abstract: The object of this research was to determine if the isotope ratios of lead were significantly different in various environmental media and if such differences could be used to distinguish the lead in the media. Significant differences in the lead isotopic ratios in rock and soils, grasses, tree leaves and tree rings, air particulate, and in some industrial products such as coal, fly ash, gasoline, and fuel oil have been found. Leaf, grass, and soil samples taken across the New Jersey Turnpike showed a change in lead isotopic ratios from the Turnpike to a point one mile to windward. The mean value of the Pb-206/Pb-204 ratio in topsoil within 500 feet of the Turnpike was 18.2 +/- 0.2 and beyond 500 feet was 18.7 +/- 0.15. Lead sampled from soil profiles in two forested locations in northern New Jersey showed an increase in Pb-206/Pb-204 ratios, with depth from 18.7 to 19.9 in a 30-inch profile. The lead abundance decreased from 47.5 to 12.0 ppm. The mean ratios of Pb-206/Pb-204 from coal and gasoline analyzed were found to be 18.8 +/- 0.2 and 18.3 +/- 0.3, respectively. The mean value for the same ratio in the published data on coal ismore » somewhat higher. Fly ash and the coal from which it came both contained lead of the same isotopic ratio. 8 references, 12 figures, 3 tables.« less
178 citations
170 citations
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152 citations
TL;DR: In this paper, the authors collected data from 32 stations across the United States and found that the North-West region of the U.S. is CONSPICUOUSLY Low in ContAMINATION; the NORTH-EST Region is Relativously High; and the SOUTH-WEST and SOUTHEAST Varying from Low to MODERATE, DEPENDING ON METAL, depending on the METAL.
Abstract: ATMOSPHERIC PRECIPITATION SAMPLES COLLECTED BY A NATIONWIDE NETWORK OF 32 STATIONS THROUGHOUT THE UNITED STATES WERE ANALYZED FOR LEAD, ZINC, COPPER, IRON, MANGANESE AND NICKLE BY ATOMIC ABSORPTION. VALUES FOR EACH STATION, AVERAGED OVER APPROXIMATELY SIX MONTHS DURING 1966 AND 1967, INDICATE HUMAN ACTIVITY AS THE PRIMARY SOURCE OF THESE MATERIALS IN ATMOSPHERIC PRECIPITATION. THE STUDY REVEALS THAT THE NORTHWEST PORTION OF THE U.S. IS CONSPICUOUSLY LOW IN CONTAMINATION; THE NORTHEAST IS RELATIVELY HIGH; AND THE SOUTHWEST AND SOUTHEAST VARY FROM LOW TO MODERATE, DEPENDING ON THE METAL. THE CONCENTRATION OF LEAD IN PRECIPITATION WAS FOUND TO BE CORRELATED WITH THE AMOUNT OF GASOLINE CONSUMED IN THE AREA IN WHICH THE SAMPLE WAS COLLECTED. THE OVERALL MEAN CONCENTRATIONS OF THE METALS IN PRECIPITATION ARE COMPARED WITH ANALOGOUS VALUES IN SURFACE WATER SUPPLIES. /AUTHOR/
135 citations
125 citations
TL;DR: In this article, the authors show that a relationship exists between traffic volume and the amount of lead in the air, and that the effect of traffic density on the lead content of the air is at a maximum at distances greater than 250 feet.
Abstract: THESE STUDIES SHOW THAT A RELATIONSHIP EXISTS BETWEEN TRAFFIC VOLUME, PROXIMITY TO THE HIGHWAY, ENGINE ACCELERATION VS. CONSTANT SPEED, WIND DIRECTION, AND THE AMOUNT OF LEAD IN THE AIR. AT LOCATIONS NEAR THE HIGHWAY, THE EFFECT OF TRAFFIC DENSITY ON THE LEAD CONTENT OF THE AIR IS AT A MAXIMUM, BUT, AT DISTANCES GREATER THAN 250 FEET, THE EFFECT OF THE TRAFFIC DENSITY IS LARGELY LOST. MORE THAN 65% OF THE LEAD IN THE AIR FROM 30-1750 FEET FROM A WELL TRAVELED HIGHWAY (48,000 CARS DAILY) CONSISTS OF PARTICLES UNDER 2 MICRON IN DIAMETER, AND MORE THAN 85% CONSISTS OF PARTICLES UNDER 4 MICRON IN DIAMETER. /AUTHOR/
TL;DR: In this paper, the amount of lead found in the surface soil did not exceed 52 ppm, a level which is common to many soils from areas of low motor vehicle traffic density and not subjected to atmospheric or industrial lead contaminations.
Abstract: Accumulation of lead in soils over a period of approximately 40 years was compared for areas of high and low motor vehicle traffic densities. Where motor vehicle traffic density was less than 80 motor vehicles per square mile, no lead accumulations were observed, but where the motor vehicle traffic density was greater than 580 motor vehicles per square mile, the concentration of lead in the surface 2.5 cm. of soil increased by a factor of two to three times. Although large percentage increases were observed in the surface soils from the areas of high motor vehicle traffic density, the amount of lead found in the surface soil did not exceed 52 ppm, a level which is common to many soils from areas of low motor vehicle traffic density and not subjected to atmospheric or industrial lead contaminations.
TL;DR: In this article, a vehicle is operated on a chasses dynamometer and controlled by magnetic tapes recorded on the road, and the exhaust is diluted with air in a mixing tunnel and a near-proportional sample obtained using the variable dilution principle.
Abstract: Experimental techniques and equipment required to provide representative samples of particulate matter from the exhaust of vehicles are considered. A system capable of sampling the exhaust from a vehicle under realistic operating conditions has been constructed. The vehicle is operated on a chasses dynamometer and controlled by magnetic tapes recorded on the road. The exhaust is diluted with air in a mixing tunnel and a near-proportional sample obtained using the variable dilution principle. During each run a number of samples are collected simultaneously to confirm the measurements made with different instruments, as well as to provide a mass balance. The sampling system can be used with a variety of instruments to characterize particulate matter emitted in the exhaust in terms of particle size, particle size distribution, physical structure, and composition. An exhaust filter has been developed to withstand exhaust gas temperatures, and is connected directly to the vehicle tail pipe. This filter has been shown to quantitatively collect exhaust lead compounds and thus provide the means to investigate the effect of vehicle characteristics and driving conditions on lead emissions. 13 references, 16 figures, 4 tables.
TL;DR: The effect of airborne lead on the lead concentration of the edible and non-edible portions of several important types of food crops was studied by growing crops in greenhouses supplied with filtered and ambient air, and in plots planted in long rows perpendicular to a busy highway.
Abstract: The effect of airborne lead on the lead concentration of the edible and nonedible portions of several important types of food crops was studied by growing crops in greenhouses supplied with filtered and ambient air, and in plots planted in long rows perpendicular to a busy highway. Of the ten crops studied - wheat, potatoes, tomatoes, sweet corn, carrots, cabbage, oats, rice, leaf lettuce, and snap beans - eight were not affected by the concentration of lead in air. In both sets of tests, inedible portions of the plants (bean leaves, corn husks, soybean husks, and oat, wheat, and rice chaff) showed a two- to three-fold increase in lead concentration when grown near the road or in the greenhouse with unfiltered air. The conclusions are reached that lead occurring naturally in the soil is the main source of lead in the edible portion of the crops studied, and that airborne lead, based on the crops studied, contributes 0.5 to 1.5% of the lead content of the US diet.
TL;DR: In this article, the amount of ammonia volatilization and nitrate accumulation under simulated feedlot conditions depended on the moisture content of the soil, and the stocking rate and other management factors should be considered in pollution abatement.
Abstract: Animals fed for slaughter are being concentrated in large feedlots, and, in some cases, contamination of ground and surface water supplies has resulted. In laboratory model studies, the amounts of ammonia volatilization and nitrate accumulation under simulated feedlot conditions depended on the moisture content of the soil. When urine was added every 2 days to an initially wet soil at the rate of 5ml per 21 cm/sup 2/, less than 25% of the added N was lost as ammonia and about 65% was converted to nitrate. When urine was added every 4 days to initially dry soil, essentially all the water evaporated between urine additions, and 90% of the added N was lost as ammonia. These findings suggest that the stocking rate and other management factors should be considered in pollution abatement.
TL;DR: The rate of nitrogen fixation by soil samples from various California environments was determined at monthly intervals for a period of one year by comparing direct isotopic observations of fixation rates with rates determined by the acetyleneethylene method.
Abstract: The rate of nitrogen fixation by soil samples from various California environments was determined at monthly intervals for a period of one year by comparing direct isotopic observations of fixation rates with rates determined by the acetyleneethylene method. Annual fixation rates of approximately 5 kg. nitrogen per hectare per year were observed in the most favorable environment examined, and rates as low as 2 kg. per year were observed on a more arid site with native vegetation. Observations made by direct isotopic methods compared reasonably well with those obtained with useof theacetylene-ethylene method, but some variability between the two occurred. Limiting factors in the fixation reaction are reported and the significance of observed rates is discussed.