Showing papers in "Journal of Environmental Quality in 1974"

Plant uptake of cadmium as influenced by cation exchange capacity, organic matter, zinc, and soil temperature

Abstract: The effects of several soil factors on cadmium (Cd) accumulation by plants were determined. Cadmium concentration in oat shoots (Avena sativa L.) was decreased by increasing the cation exchange capacity (CEC) of the soil. Except for its CEC effect, organic matter did not influence the concentration of Cd in oat shoots. The results indicate that the retaining power of organic matter for Cd is predominately through its CEC property rather than chelating ability. Cadmium concentration of soybean shoots (Glycine max L.) increased soil temperature. In the presence of 10 ppm of soil-applied Cd, the addition of Zn from the 5 to 50 ppm range, apart from raising the Zn concentration, significantly increased the Cd concentration of soybean shoots. The increased Cd concentration was primarily due to decreased plant growth. A depression in Cd concentration of soybean shoots, relative to control, began to occur at the 100 ppm Zn level. 12 references, 5 tables.

A Simulation Model for Prediction of Herbicide Persistence

Abstract: A simulation model for prediction of herbicide persistence in the field is described. The model combines the effects of soil temperature and soil moisture content on the rates of herbicide loss, determined experimentally under controlled conditions, with the fluctuations in surface soil temperature and moisture content in the field. The computer program includes methods of simulating surface soil temperatures and moisture contents from standard meteorological data. In order to test the model, the degradation of napropamide (2-(a-naphthoxy)-N,N-diethylpropionamide) was examined. Under controlled conditions, loss of activity followed first-order kinetics with half-lives of 54, 63, and 90 days at 28C with soil moisture contents of 10.0, 7.5, and 3.5%, respectively. At 14C, half-lives at 10.0 and 7.5% soil moisture were 102 and 112 days, respectively. When these data were used in the simulation model in conjunction with the relevant meteorological information, the patterns of loss of napropamide incorporated 2 to 3 cm in the field could be predicted. Napropamide was lost rapidly when applied to the soil surface, and since the model only takes into account losses through microbial or chemical metabolism, this could not be simulated. Some of the limitations and the potential benefit of the simulation technique for prediction of pesticide persistence are discussed.

Water Quality After Clearcutting a Small Watershed in West Virginia

Abstract: A 34-ha (85-acre) gaged watershed on the Fernow Experimental Forest, Parsons, West Virginia, was conventionally clearcut in 1969. Streamflow increased 20 cm (8 inches) during the first year after cutting, but rapid and luxuriant revegetation reduced the flow increase to only 6.4 cm (2.5 inches) during the second year. Water quality remained high. Clearcutting had a negligible effect on the stream's temperature, pH, nonstorm turbidity, and concentrations of dissolved solids, Ca, Mg, Na, K, Fe, Cu, Zn, Mn, and NH4-N. Storm-period turbidity, nitrate-nitrogen, and phosphate concentrations showed slight increases, while the sulfate concentration decreased. Maximum nitrate-nitrogen concentration of 1.42 ppm was recorded during a 6.4-cm (2.5-inch) rainfall. Success in avoiding damage to water quality was attributed to careful road management, retention of a forest strip along the stream, and rapid, lush vegetative regrowth after Clearcutting. Additional Index Words: Even-aged forest management, logging, water chemistry, turbidity, specific conductance, nutrient concentrations, nutrient outflow, nitrates, stream temperature, water yield, streamflow. More and more people are taking an interest in how our forests are managed. Responsible people are asking a valid question—how does clearcutting affect the quantity and quality of the water flowing from clearcut lands? Years of research have shown that forest cutting increases and reforestation decreases water yield. The practical upper limit of yield increase appears to be about 4.5 mm/year for each percent reduction in forest cover, but most treatments produce less than half this amount. As reforestation proceeds after treatment water yield declines; the rate of decline varies between watersheds but appears to be related to the rate of forest recovery (3). The question of how does clearcutting affect the quality of water flowing from clearcut lands is not as easily answered. All streams contain varying amounts of nonwater substances, either dissolved or suspended in the water. And all of these substances affect the water quality in some manner. The traditional criterion of quality in forest streams, turbidity, is no longer sufficient. Looks can be deceiving; a sparkling, crystal-clear stream may have undesirable chemical characteristics. Only recently has research been directed to the effects of forest cutting on the chemical composition of streams draining cutover areas. A study on the Hubbard Brook Experimental Forest in New Hampshire focused attention on changes in the chemical composition of streams after deforestation (5). The treatment was strictly experimental. The trees were felled and left in place, lesser vegetation was killed, and regrowth was prevented by repeated applications of herbicide. This treatment was followed by such a large outflow of nutrients that water quality was adversely affected. Results of this experimental treatment caused many to express fears that all clearcutting will adversely affect water quality. There is a substantial difference between the Hubbard Brook treatment and conventional clearcutting. Conventional clearcutting also features complete forest cutting; but all saleable wood is harvested and rapid forest regeneration is encouraged. On the hypothesis that large nutrient outflow is not necessarily a result of conventional clearcutting, we began a study in 1969 on the Fernow Experimental Forest to provide information about the effects of clearcutting on water quality. In this paper conventional clearcutting is defined as the silvicultural method in which all trees on a given area are harvested in one cut; saleable logs and pulpwood are removed; and culls, small stems, and all other undesirable trees remaining after the harvest operation are cut or treated so that they will not interfere with the establishment of a new even-aged stand. This report summarizes our findings and conclusions from 2 years of close observation. 'Contribution from the Northeastern Forest Exp. Sta., USDA Forest Service. Received 9 June 1972. Soil Scientist and Forest Hydrologist at the USDA Forest Service Timber and Watershed Laboratory, Parsons, W. V. J. Environ. Quality, Vol. 3, no. 3,1974 243

Nitrogen-15 Variations in Fertilizer Nitrogen

Abstract: Nitrogen-15 concentrations of some commonly used nitrogen fertilizers are measured. Ammonium-nitrogen has lower and nitrate-nitrogen has higher ¹⁵N concentrations than atmospheric nitrogen. The mean difference between both is about 4 δ ¹⁵N.

Lead, Cadmium, and Calcium Selectivity Coefficients on a Montmorillonite, Illite, and Kaolinite

Abstract: Selectivity coefficients for Pb/sup 2 +/, Cd/sup 2 +/, and Ca/sup 2 +/ exchange adsorption with montmorillonite, illite, and kaolinite clays were determined over a wide range of clay surface concentration and found constant. The average selectivity coefficients describing the ion distributions for montmorillonite, illite, and kaolinite, respectively, were 0.60, 0.44, 0.34 for Pb-Ca exchange, 1.04, 1.01, 0.89 for Cd-Ca exchange, and 0.58, 0.56, 0.31 for Pb-Cd exchange. Whereas Cd/sup 2 +/ may compete more or less on an even basis with Ca/sup 2 +/ for clay adsorption sites, the adsorption of Pb/sup 2 +/ would be favored by a factor of 2 or 3 over Ca/sup 2 +/. 21 references.

Predicting Pesticide Runoff from Agricultural Land: A Conceptual Model

Abstract: A mathematical model of the dynamic, single-rainfall-event type is being developed to describe quantitatively pesticide runoff as a function of pesticide and soil properties, agricultural practices, watershed characteristics, and climatic factors. From the model, guidelines governing pesticide use will be derived to prevent or minimize water pollution resulting from runoff from agricultural land. The model described is based on a state-of-the-art approach. Pesticide transport is “piggybacked” on existing hydrologic and soil-loss models. Both direct mass-balance and areal averaging-statistical simulation approaches are being considered for the basic runoff and sediment transport descriptors. The conceptual structure of the overall model includes (i) source term effects (parameters that determine the initial concentration of pesticide available for runoff), e.g., pesticide formulation, physical-chemical properties, and initial spatial distribution; (ii) loss of pesticide from the surface zone between rainfall events by various attenuation processes (volatilization, microbial, chemical, and photochemical degradation, and organism uptake); and (iii) loss of pesticide from the soil surface during runoff-producing rainfall events because of mass transfer from soil surface into the moving runoff film and pickup of sediment containing pesticide particulates. The minimum output requirements for the model are the prediction of runoff rate and sediment loading plus the corresponding water and sediment phase pesticide concentrations at a designated boundary (normally a watershed confluence or drainage channel) as a function of time during a runoff event. This output is to be based upon input consisting of the type, formulation, and rate and method of application of the pesticide, and the areal extent, topography, type of soil, cropping characteristic, and rainfall characteristics of the watershed or basin. The model will internally generate and store the appropriate boundary condition changes required to predict sequential rainfall response using between-event meteorological data as input. In addition, the model structure is to be suitable for scaleup for application to areas approaching basin size parametrically, by use of transfer functions, or by use of executive and routing subroutine additions.

Differing Sensitivity of Corn and Soybean Photosynthesis and Transpiration to Lead Contamination

Abstract: Corn (Zea mays L.) and soybean (Glycine max L.) plants grown in media containing a range of Pb concentrations, supplied as PbCl₂, showed decreased net photosynthesis and transpiration with increasing Pb treatment levels. At lower Pb treatment levels, corn appearsto be more sensitive than soybeans. However, at high treatment levels (62.5–250 mg/plant) soybeans are more sensitive than corn. At 250 mg Pb/plant in the medium, photosynthesis is only 10% of maximum in soybeans but 47% in corn, even though corn Pb tissue content is much higher than that of soybeans. Transpiration exhibited similar trends to photosynthesis suggesting that, especially in corn, an appreciable part of the inhibition of the two processes is related to increased stomatal resistances with increased Pb concentrations. Lead accumulation trends were similar at treatment levels of 0 to 62.5 mg/plant but were slightly different at higher levels. The total amount of Pb accumulated was higher in corn than in soybeans. Maximum accumulation in both species occurred at 62.5 mg Pb/plant.

Soil Profile Conditions of Cattle Feedlots

Abstract: Characterization of the conditions that exist in the feedlot surface and soil profile is important to evaluation of the potentials for soil and water pollution. Cattle action and management activities create a dynamic condition in the feedlot. The organic matter surface causes physical and biochemical changes in the soil that are unlike natural or cultivated soils. The feedlot profile can be described as three layers: the organic matter, the interface, and the underlying soil. Measurable characteristics include bulk density, infiltration, and content of organic matter, water, and nitrate-N. Generally, the surface 15.2-cm depth of feedlot soils is compacted and has a high bulk density. Infiltration into the feedlot surface layers is essentially zero. There is no transpiration, and the soilwater content is more uniform through the profile than on cropped land.

Transformations of Methylamines and Formation of a Hazardous Product, Dimethylnitrosamine, in Samples of Treated Sewage and Lake Water

Abstract: Added trimethylamine is converted to dimethylamine in samples of raw sewage and lake water, and the secondary amine thus formed or added dimethylamine disappears with time. The rates of formation and disappearance of dimethylamine are governed by the pH and the type and amount of inorganic N present. Ammonium is generated from both of the amines. Dimethylnitrosamine, a potent carcinogen, is formed in small amounts in samples of sewage and lake water receiving dimethylamine and nitrite, the maximum nitrosamine level detected rising with increasing acidity and increasing dimethylamine and nitrite concentrations. Dimethylnitrosamine also appears in sewage and lake water samples receiving trimethylamine. Microorganisms are involved in some stage of the conversion of the tertiary amine to the secondary amine and dimethylnitrosamine in sewage because these products are not found in sterilized sewage. The fungicide thiram (tetramethylthiuram disulfide) is converted to dimethylamine in sterilized sewage at pH 4.0, and small amounts of dimethylnitrosamine are also produced in the presence of nitrite; the yields of both products are far greater in nonsterile, thiram-amended sewage. The identification of dimethylnitrosamine was verified by thin-layer and gas chromatography, ultraviolet and infrared spectrometry, and combined gas chromatrophy-mass spectrometry.

Columns Representing Mound-type Disposal Systems for Septic Tank Effluent: II. Nutrient Transformations and Bacterial Populations

Abstract: Carbon, nitrogen, and phosphorus transformations and bacterial populations were studied in columns representing a mound disposal system. Total-N, total-P, and the chemical oxygen demand (COD) of the influent (septic tank effluent) averaged 42, 21, and 257 mg/liter, respectively. The reduced-N forms present in the influent (NH₄-N and organic-N) were oxidized to NO₃-N in the aerobic fill and about 32% of the total-N was lost by denitrification during water passage through the anaerobic silt loam at the bottom of the column. Phosphorus (mainly dissolved orthophosphate) concentrations in column effluents, increased gradually, stabilizing at about 60% of the influent P concentration. Phosphorus removal from the percolating water probably occurred by both sorption and precipitation. The COD of column effluents was very low, indicating essentially complete C removal. After crusting developed and caused permanent ponding the fill became anaerobic, and the column effluent N was mainly NH₄-N. Phosphorus concentrations of the effluent increased gradually with time and reached a constant value of 2 to 6 ppm. The COD of the effluent from the totally anaerobic columns was higher than that from the uncrusted columns. Perforating column walls to more closely simulate field conditions permitted aerobic conditions in the fill after crust development caused continuous ponding. The C, N, and P transformations in the perforated crusted columns were similar to those observed in the nonperforated uncrusted (i.e., aerobic) columns. Fecal indicator bacteria were not detected in any column effluent even though the counts of fecal streptococci and fecal coliform in the influent averaged 3.8 × 10⁴ and 1.7 × 10⁵/100 ml, respectively.

Nitrogen Loss from Manure as Influenced by Moisture and Temperature

Abstract: Soil temperature and moisture are important in cattle waste management. The effects of these two variables on N losses from different rates of applied manure were studied under greenhouse conditions at two soil moisture (60 and 90% of water saturation percentage, WSP) and two soil temperature (10 and 25C) levels. The manure rate did not have a significant effect on the percentage of loss of applied N. At 10C, the average losses of applied N were 26 and 39%, respectively, for the 60 and 90% moisture levels. Higher losses of 40 and 45% were obtained for the 60 and 90% levels, respectively, at 25C. Results suggest that these losses occurred largely through volatilization of NH₃. Under conditions where significant nitrification occurred, there were greater concentrations of electrolytes associated with reduction in pH indicating that leaching of NO₃⁻ cannot be divorced from soluble salts in manure disposal areas. With N losses approaching 50% of the applied N, large quantities of N are being volatilized to the atmosphere over large and concentrated dairy and feedlot areas.

The Effects of SO2 on in vitro Forest Tree Pollen Germination and Tube Elongation

Abstract: The effects of SO₂ on in vitro pollen germination and tube elongation were examined for Populus deltoides (Bartr.), Pinus resinosa (Ait.), Pinus nigra (Arnold), and Picea pungens (Engelm.). Comparisons were made between pollen fumigated in a dry condition and then placed on the germinating media, and moist pollen fumigated while on the germinating media. Moist P. deltoides pollen germination was significantly reduced at SO₂ concentrations of 0.75 ppm and above. Populus deltoides pollen tube elongation was more sensitive to SO₂ exposure and highly significant decreases in tube length occurred at 0.30 ppm for 4 hours. Tube elongation decreased linearly with increases in SO₂ concentration. Frequent bursting of pollen tubes occurred at SO₂ concentrations greater than or equal to 0.3 ppm for 4 hours. Exposure to SO₂ caused similar effects on pollen germination and tube elongation for Pinus resinosa, Pinus nigra, and Picea pungens. Moist pollen was far more sensitive than dry pollen to SO₂ exposure. A 4-hour exposure to 1.4 ppm SO₂ severely restricted moist pollen germination and tube elongation of the three conifer species. However, a similar exposure to 10 ppm SO₂ had no effect on dry pollen of the three species. Absorption of SO₂ resulted in an acidification of the germination media. Germination trials on acidified media indicated that the resultant acidification could account for much of the reduced germination and tube elongation in P. deltoides but could not adequately explain the reduced conifer pollen germination and tube elongation.