Browsing by Author "Thomann, Robert V."
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Item An Age Dependent Model Of PCB In A Lake Michigan Food Chain(1981-09-30) Thomann, Robert V.; Connolly, John P.An age-dependent food chain model that considers species bioenergetics and toxicant exposure through water and food is developed. It is successfully applied to PCB contamination of the Lake Michigan lake trout food chain represented by phytoplankton, Mysis, alewife, and lake trout. The model indicates that for the top predator lake trout, PCB exposure through the food chain can account for greater than 99 percent of the observed body burden. A simple steady-state computation indicates that ratios of chemical concentration in predators to that in prey in feeding experiments may be as low as 0.2 and still result in significant food chain transfer. It is estimated that a criterion specifying that PCB concentrations of all ages of lake trout be at or below 5 ug/g (wet weight) in the edible portion would require that dissolved PCB concentrations be reduced to somewhere between 0.5 and 2.5 ug/R. The range reflects uncertainty in the PCB assimilation efficiency of the species and the dissolved PCB concentration. This report was submitted in fulfillment of Cooperative Agreement No. CR805916010 by Manhattan College under the sponsorship of the U.S. Environmental Protection Agency. This report covers the project period May 1, 1978 to September 30, 1981.Item Documentation For Water Quality Analysis Simulation Program (WASP) And Model Verification Program (MVP)(1983-05) Di Toro, Dominic M.; Fitzpatrick, James J.; Thomann, Robert V.; Hydroscience, Inc.A generalized water quality modeling program and a model verification analysis program have been developed that have application to a wide variety of water resource management problems. The Water Quality Analysis Simulation Program, WASP, is based on the flexible compartment approach. It may be applied to water bodies in a one, two, or three-dimensional configuration, and kinetic models may be structured to include linear and non-linear reactions. The user may choose, via input options, to employ constant or time-variable transport and kinetic processes, as well as point and nonpoint waste discharges. The Model Verification Program, MVP, may be used as an indicator of "goodness of fit" or adequacy of the model as a representation of the real world. To date, WASP has been applied to over twenty water resource management problems. These applications have included one, two and three-dimensional configurations and a number of different physical, chemical and biological modeling frameworks, such as BOD-DO, eutrophication, and toxic substances. A user's manual and program listings have been prepared. The user's manual was oriented towards the system analyst, whose responsiblity it would be to design, develop and debug new kinetic models for end users, as well as the end user who must prepare the data input to the program.Item A Dynamic Model of Phytoplankton Populations in Natural Waters(1970-06) DiToro, Dominic M.; O'Connor, Donald J.; Thomann, Robert V.Item Dynamic Water Quality Forecasting And Management(1973-08) O'Connor, Donald J.; Thomann, Robert V.; Di Toro, Dominic M.This report describes the formulation and initial verification of two modeling frameworks. The first is directed toward an analysis of the impact of the carbonaceous and nitrogenous components and wastewater on the dissolved oxygen resources of a natural water system. The second modeling framework concentrates on the interactions between the discharge of nutrient, both nitrogen and phosphorus, and the biomass of the phytoplankton ,and zooplankton populations which result, as well as incorporating the overall impact on dissolved oxygen. The models are formulated in terms of coupled differential equations which incorporate both the effect of transport due to tidal motion and turbulence, and the kinetics which describe the biological and chemical transformations that can occur. The modeling frameworks are applied to the Delaware and Potomac estuaries in order to estimate the ability of such models to describe the water quality effects of carbon, nitrogen, and phosphorous discharges. The agreement achieved between observation and calculation indicate that the major features of the impact of wastewater components on eutrophication phenomena can be successfully analyzed within the context of the model presented herein. This report was submitted in fulfillment of Project Number R800369, by Manhattan College, Bronx, New York, under the sponsorship of the Environmental Protection Agency. Work was completed as December 31, 1972.Item Mathematical Modeling of Phytoplankton in Lake Ontario,Part 2 Simulations Using Lake 1 Model(Enviromental Protection Agency (EPA), 1976-08) Thomann, Robert V.; Winfield, Richard P.; Di Toro, Dominic M.; O'Connor, Donald J.The results of a series of simulations of the response of the open lake region of Lake Ontario to various levels of nutrient input are described in this report. The simulations use a simplified dynamic model of phytoplankton nutrient interactions in a vertically segmented structure. The lake is assumed to be well-mixed in the horizontal direction. The problem of long term simulations (10-20 years) that draw on short term observation and verification periods (5 years) is discussed and it is indicated that the overall loss rates of nutrient are of particular importance. Under a hypothesized, but reasonable, set of model parameters, the simulations indicate that the present observed open lake phytoplankton biomass of Lake Ontario does not appear to be in equilibrium with the present input nutrient load. Therefore, if the present load is continued, it is estimated that spring peak phytoplankton chlorophyll in the epilimnion will continue to increase to a new level about 45% higher than present levels. The interaction of nitrogen and phosphorus is also described by the simulations and the results indicate a tendency for nitrogen limitation to be an increasing dominant factor in controlling the spring bloom. A pastoral" simulation using load estimates, indicative of conditions prior to man's intensive activity provides an approximation of an early state of the lake. This "hindcast" indicates that spring phytoplankton levels were some 40% less than present levels and average annual epilimnion biomass under equilibrium with present loads is about twice that under pastoral conditions. A series of analyses is also conducted comparing simulations from the dynamic model to estimates made from simplified plots of loading versus lake geometry. The results from the dynamic model indicate that a reduction in external nutrient load does not result in an accompanying decrease in phytoplankton biomass, due to the hypothesized non-equilibrium condition of Lake Ontario. The dynamic model results are therefore in contrast to the results one would obtain from using "admissable" loading concept which indicates an improvement in lake trophic status. Analysis of lake response to the U.S.-Canada Water Quality Agreement (WQA) loads using the hypothesized parameters indicates about a 6% reduction in peak phytoplankton at equilibrium. The implications of the results appear to be of some importance since the analyses indicate that it may difficult to achieve measurable reductions below present levels of phytoplankton biomass in the open lake. From a decision and policy making viewpoint then, the simulations tend to indicate that maximum point source nutrient control for Lake Ontario will, at best, be a "ho1ding" action rather than a significant improvement in the status of the be open lake. This report was submitted in partial fulfillment of Grant Number R 800610 to the Environmental Engineering and Science Program, Manhattan College, Bronx, New York by the U.S. Environmental Protection Agency. Work was completed as of April, 1975.Item Physico-Chemical Model Of Toxic Substances In The Great Lakes(1983-08) Thomann, Robert V.; Di Toro, Dominic M.A physico-chemical model of the fate of toxic substances in the Great Lakes is constructed from ash balance principles and incorporates principal mechanisms of particulate sorption-desorption, sediment-water and atmosphere-water interactions, and chemical and biochemical decay. The steady state mass balance model of the suspended solids in the open lake water yields net solids settling velocities from 0.02 m/d for Saginaw Bay to 1.33 m/d for Lake Ontario. Calibration of the toxic model is through comparison to plutonium-239 data collected in the 1970's using a 23 year time variable calculation. 239Pu partition coefficient of 400,000 l/kg, a particulate settling velocity of 2.5 m/d, associated lake specific net sedimentation and resuspension velocities provided a good calibration to the observed time variable 239Pu behavior. An assumption of zero resuspension of the sediment did not provide a good calibration. The results indicate that, in general, the sediments are interactive with the water column in the Great Lakes through resuspension and horizontal transport. Fifty percent response times of 239Pu tollowing a cessation of load extend beyond 10 years with sediment resuspension. The calibrated model was applied to polychlorinated biphenyl (PCB) using a high and low estimate of contemporary external load and with and without volatilization. The results of the application indicate that the upper load level (lake range of 400-9500 kg/yr) without volatilization is not representative of the surface sediment data and very limited water column data. The lower load level (lake range 640-1390 kg/yr) with volatilization (at an exchange rate of 0.1 m/d) appears to be more representative of observed surface sediment data for the open lake waters. Calculated water column concentrations for the lower load level with and without volatilization ranged from 0.25 to 0.90 ng/l for open lake waters. Fifty percent response times for PCB following cessation of load and including volatilization varied from less than 5 years to 10-20 years for the other lakes without volatilization. Comparison of these response times to decline of concentrations of PCB in Lake Michigan indicates that at least for that lake volatilization is occurring at an exchange rate of about 0.1 m/d. Calculations using a solids dependent partition coefficient for PCB indicate that the total and dissolved PCB concentration in the water column and sediment PCB concentration are affected to less than an order of magnitude. Interstitial PCB concentration however increases by about two orders of magnitude over the case with a solids independent partition coefficient. Higher exposure concentrations to benthic organism may then result with a potential route of PCBs to the top predators in the food chain.Item Technical Analysis Of Response Of Chesapeake Bay Water Quality Model To Loading Scenarios(1994-04) Thomann, Robert V.; Collier, James R.; Butt, Arthur; Casman, Elizabeth; Linker, Lewis C.Item Verification Analysis Of Lake Ontario And Rochester Embayment Three Dimensional Euthophication Models(1979-08) Thomann, Robert V.; Winfield, Richard P.; Segna, John J.A three dimensional time variable model of the phytoplankton and nutrients of Lake Ontario and the Rochester Embayment is examined in detail. The data from the International Field Year on the Great Lakes (IFYGL) are used as the primary data base. The data are summarized and statistically analyzed on a three dimensional grid and segment averages using a 67 segment representation of the lake and a 72 segment representation of Rochester Embayment, are calculated. In addition, averages for eight regions of the lake and lake wide averages for two depth layers are computed. Average phytoplankton levels during the period May, 1972 and June, 1973 in the near shore region are approximately 3 ug/l higher than open lake values. Similarly, near shore open lake total phosphorus gradients of about 5 ug P/L appear to persist for a substantial part of the year. The data base collected during IFYGL exhibited significant spatial and temporal variations at scales of 10 x 40 km. The two data bases available, Canadian Centre for Inland Waters (CCIW) and Environmental Protection Agency (EPA), only agree within certain limits. The verification analysis of the models indicates that the median relative error for the results of calculated versus observed chlorophyll on the segment to segment level is about 30%. The inclusion of diatoms and nondiatoms and silica limitation in the kinetic structure, only marginally improved the three dimensional credibility of the model. The Rochester Embayment model indicated that about 90% of the total phosphorus input to the embayment is transport of nutrients from the west of the embayment and about 10% is from direct input from the Genesee River and municipal input from the City of Rochester. The question of model credibility is examined in detail and it is concluded that as one progresses to smaller spatial scales, especially to the scale of the Rochester Embayment, hydrodynamic transport and local dispersion become increasingly significant. On the larger spatial scales, system kinetics dominate and the importance of the hydrodynamic structure is decreased. Chlorophyll verification status, of the model ranges from an average of 10% relative error on the whole lake scale to 50% error at the local embayment scale. In general, the results indicated that the ability of complex three dimensional models to capture the temporal and spatial variability of phytoplankton dynamics is relatively marginal given the existing data base and present kinetic structures. Only as the spatial scale of the problem is increased, do the models appear to accurately reflect the observed variations.Item Water Quality(The Sea Grant Institute of SUNY and Cornell University, 1977-10) O'Connor, Donald J.; Thomann, Robert V.; Salas, Henry J.This monograph describes the water quality of New York Bight as measured by temperature, light, salinity, dissolved oxygen, various nitrogen and phosphorus forms, pH, heavy metals, coliform bacteria, and phytoplankton chlorophyll. Major water quality monitoring in the Bight, initiated in 1948, has been sporadic in the past with gaps from 3 to 10 years when no major sampling was conducted. These data indicate that bottom dissolved oxygen percent saturation levels in the disposal areas of the apex have decreased from 67% in 1949 to 30% in 1974. Surface total iron concentrations in the apex have increased from 20 u/l in 1949 to about 90 u/l in 1969, and are higher than background open ocean levels. Coliform bacterial influence appears to be confined to an area of 3.2 to 4.8 km (2 to 3 mi) radius from the discharge point of a sewage sludge barge dump. Nitrogen is generally the more important nutrient relative to phosphorus with respect to limiting phytoplankton growth in the Bight. Man’s impact on the water quality of the region appears to be significant with more than 50% of the total input of iron, copper, cadmium, chromium, suspended solids, and total phosphorus attributed to barge discharges alone. An overall analysis of New York Bight to quantitatively assess the relative impact of the major discharges is recommended.Item Water Quality Analysis Simulation Program (WASP)(1900) DiToro, Dominic; Fitzpatrick, James J.; Thomann, Robert V.A generalized water quality modeling program and a model verification analysis program have been developed that have application to a wide variety of water resource management problems. The Water Quality Analysis Simulation Program, WASP, may be applied to one, two, and three-dimensional water bodies, and models may be structured to include linear and non-linear kinetics. Depending upon the modeling framework the user formulates, the user may choose, via input options, to input constant or time-variable transport and kinetic processes, as well as point and non-point waste discharges. The Model Verification Program, MVP, may be used as an indicator of "goodness of fit" or adequacy of the model as a representation of the real world. To date the water quality modeling program has been applied to over twenty water resource management problems. These applications have included one, two and three dimensional water bodies and a number of different physical, chemical and biologica1 modeling frameworks, such as BOD-DO, eutrophication, and toxic substances.Item Workshop On Verification Of Water Quality Models(1980-04) Thomann, Robert V.; Barnwell, Thomas O. Jr.The U.S. Environmental Protection Agency sponsored a "National Workshop on the Verification of Water Quality Models" to evaluate the state-of-the-art of water quality modeling and make specific recommendations for the direction of future modeling efforts. Participants represented a broad cross-section of practitioners of water quality modeling in sections of government, academia, industry and private practice. The issues discussed during this workshop, which was held in West Point, N.Y., on 7-9 March 1979, were models in decision making, model data bases, modeling framework and software validation, model parameter estimation, model verification and models as projection tools. These issues were discussed by workshop participants who were organized into small groups, each of which discussed the state of the art of a specific branch of water quality modeling. Groups were divided into areas of wasteload generation, transport, salinity-TDS, dissolved oxygen-temperature, bacteria-virus, eutrophication and hazardous substances. Workshop findings were summarized by committee reporters and are presented in state-of-the-art reports. Workshop participants also presented basic issue reports and technical support papers, all of which are included in this document. This report was submitted,in partial fulfillment of Contract No. 68-01-3872 by Hydroscience, Inc., under the sponsorship of the U.S. Environmental Protection Agency. This report covers the period from September 1979 to December 1979, and work was completed as of December 1979.