Research Projects 2007

• Active Biomonitoring for PCB, PAH and Chlordane Pollutants in the Nontidal Sources of the Anacostia Watershed
• Decision support system to deal with water emergencies for Metropolitan DC
• Gradual Variation Analysis for Groundwater Flow in the District of Columbia
• Modeling of an Integrated Urban Wastewater System in the District of Columbia
• Molecular Signaling by Environmental Arsenicals in Mammalian Cells

Active Biomonitoring for PCB, PAH and Chlordane Pollutants in the Nontidal Sources of the Anacostia Watershed

Principal Investigator:      Harriette L. Phelps, Ph.D.

The research objectives of this 2007 proposal are to address several key questions that now can be asked about Anacostia tributary contaminant sources. These questions are (1) is asphalt sealcoating, which has been banned in cities, contributing to the high PAHs downstream from industrial parks and metro stations?; (2) which upstream industrial park(s) or metro station(s) are sources of the high PCBs in Lower Beaverdam Creek?; and (3) what is the source of the high chlordane levels found in a small first-order tributary of the Northeast Branch? Carrying out these objectives will require stream walking to place active biomonitoring Corbicula (Asiatic) clams at sites close to industrial parks and metro stations and within small streams.  The answers will suggest the actions that can be taken to remediate these toxic contaminant sources in the watershed.

The highly contaminated tidal Anacostia River can not be improved until the sources of contaminants can be identified and remediated.  Previous active biomonitoring studies have located general areas of contaminant production in Anacostia tributaries.  Results of the 2007 ABM program will add crucial information needed to identify the exact locations of these contaminant sources and the specific types of contaminants.  This information is essential to plan activities for legislative measures to restore the health of the Anacostia. 

The purpose of this research project is to expand the scope of the active biomonitoring (ABM) of Anacostia tributaries that previously identified the portions with toxic pollutants.  It will give information about the nature and more precise location of the pollutant sources in these streams. The contaminants include the PAHs responsible for the high tumor incidence in catfish, and the PCBs and Chlordane causing the Anacostia fishing advisory.

Decision support system to deal with water emergencies for Metropolitan DC

The current regulation on Public Health Security and Bioterrorism Preparedness and Response Act, requires drinking water utilities serving more than 3,000 people to perform vulnerability assessments and to prepare an Emergency Response Plan (ERP). 

The ERP also must include “actions, procedures, and identification of equipment which can obviate or significantly lessen the impact of terrorist attacks or other intentional actions on the public health and the safety and supply of drinking water provided to communities and individuals.” (EPA 2003).
 
For water utilities, however, enhancing physical security and compliance of current regulation is one of many priorities. Because of the competition for limited resources, including financial and personnel, the current compliance requires a very balanced approach across each of the following five dimensions (i) financial (ii) personnel (iii) management tools, (iv) operational approaches, and (v) physical security design features. This complex decision problem requires a holistic response – especially in an emergency. Like many other metropolitan systems of the nation, the Metropolitan DC water system is a large and complex system.  Moreover, the nature of vulnerability and preparedness for DC system is unique given that it is the nation’s capital. Therefore there is a need to develop an efficient decision support system (DSS) for the water utility system which would not only provide day-to-day management support but also during emergency situations.
 
This is a collaborative research project between George Washington University (GWU) and the University of the District of Columbia (UDC). This interdisciplinary research, addressing decision making and information technology use in water security, is being carried out as a precursor to a longer-term research effort. By conducting this preliminary study, we aim to delineate and prioritize decision and information requirements based on their relevance to practicing managers and policy makers in the DC Metro area. The specific objectives of this research are:
 

• Identification of different vulnerabilities to the water system;
• Identification of gaps in the information gathering and sharing framework;
• Identification of gaps in the decision making framework as it currently exists;
• Development of a framework to address those gaps and improve response    readiness and reactions to water emergencies;
• Develop a larger proposal that will develop and deliver a suite of DSS that will  be field tested and validated.  

Gradual Variation Analysis for Groundwater Flow in the District of Columbia

Principal Investigator:      Li Chen, Ph.D

AssociateProfessor                                               Department of Computer Science and Information Technology
University of the District of Columbia
Email: lchen@udc.edu

Groundwater flow in the District of Columbia greatly influences the surface water quality in urban areas. The current methods of flow estimation, based on Darcy’s Law and the groundwater flow equation, can be described as the diffusion equation (the transient flow) and the Laplace equation (the steady-state flow). The Laplace equation is a simplification of the diffusion equation under the condition that the aquifer has a recharging boundary. The practical way of calculating is to use numerical methods to solve these equations. The most popular system is called MODFLOW, which was developed by USGS. MODFLOW was based on the finite-difference method on rectangular Cartesian coordinates. MODFLOW can be viewed as a “quasi 3D" simulation since it only deals with the vertical average (no z-direction derivative). Flow calculations between the 2D horizontal layers use the concept of leakage.   

In this proposal, we will establish a true 3D simulation model based on gradually varied functions. These functions do not rely on a rectangular Cartesian coordinate system. A gradually varied function can be defined in a general graph or network. Gradually varied functions are suitable for arbitrarily shaped aquifers. However, to ensure the accuracy of the calculation, we will add the finite-difference method to our research. That is to use MODFLOW to calculate local and small-region flow, and to use gradual variation to compute the regional or global data. The proposed research will have three steps: (1) Use the gradually varied model and simulation based on the groundwater flow in DC. (2) Decompose the DC aquifer into major 3D cells, by using MODFLOW for each cell and then the gradual variation method on the entire region. (3) Compare the results of MODFLOW, Gradual variation, and the mixed method. 

Modeling of an Integrated Urban Wastewater System in the District of Columbia

Principal Investigator:      Tolessa Deksissa, Ph.D., Research Associate

University of the District of Columbia
Washington, DC  20008
E-mail: tdeksissa@udc.edu

Co-principal Investigator:  Pradeep K. Behera, Ph.D., P.E.,

Associate Professor
Engineering, Architecture & Aerospace Technology
University of the District of Columbia
Washington, DC 20008
Email: pbehera@udc.edu

 

The ultimate objective of this study is to develop a conceptual mathematical model that can assist water quality regulators as a tool for urban wastewater management. The scheme of modeling an integrated urban wastewater system includes three components: the sewer, the wastewater treatment plant and the river. In the traditional urban wastewater modeling, these three components are considered separately and their mutual interaction among the three components is missing. Urban wastewater system must, however, be considered as a single system, and all components need to be included in one model that simulates the three components simultaneously.  Simultaneous or parallel simulation allows evaluation of system performance, and optimizing it in terms of environmentally and economically sound planning and management.

This study is a preliminary study towards a development of a conceptual integrated mathematical model of sewer, wastewater treatment plant and the river. In the integrated modeling of the wastewater treatment plant and the river, the main problem is that all of these components are not only complex, but also there is incompatibility between state variables, biochemical processes and parameters used in the different sub-models. In this study an appropriate method of model selection and building an interface between submodels will be investigated.

Approximately, one third of the District of Columbia is served by a combined sewer system, which was designed to convey sewage from homes, businesses and runoff from streets, parking lots, and rooftops to the wastewater treatment plant during dry weather flow. The capacity of the combined sewer system is limited and when it is exceeded during storms, the excess flow, which is a mixture of raw sewage and storm water runoff, is discharged to the receiving waters: Anacostia, Potomac Rivers, Rock Creek and tributary waters. Thus, Combined Sewer Overflow (CSO) allows discharging of a mixture of untreated sewage and storm water runoff to the receiving waters during high flow periods due to storms. Discharging such untreated wastewater may cause acute toxicity to the aquatic life, and if not controlled, it results in continuous deterioration of water quality of the receiving waters.

Integrated modeling helps to conduct different scenario analysis to overcome the water quality problems in the District of Columbia and other states where the receiving water quality is being adversely affected by Combined Sewer Overflows (CSOs). The proposed study is therefore helpful for a researcher or planner and regulator to detect the weak point of the system and to evaluate the efficiency of alternative action, e.g. using storm tank or sewer tunnel and low impact development.

In this preliminary study, appropriate sub model selection, model reduction, building interface, and implementation of the models will be carried out.  Also, selected water quantity and quality parameters will be collected. 

Molecular Signaling by Environmental Arsenicals in Mammalian Cells

Arsenic is a major contaminant in drinking water that is associated with skin lesions, peripheral vascular disease, hypertension and various cancers such as skin, lung and bladder cancer. Additionally, humans are exposed to organic arsenicals when used as pesticides and herbicides (e.g., monomethylarsonic acid, dimethylarsinic acid (DMAV) also known as cacodylic acid).  The main sources of arsenic in drinking water are erosion of natural deposits; runoff from orchards, runoff from glass and electronics production wastes. Although, arsenic is a known human carcinogen in vitro, the mechanisms of arsenic toxicity and its carcinogenic effects are poorly understood.  Unlike many other carcinogens, arsenical compounds do not directly induce gene mutations.  Deregulation of cell cycle is the main event in cancer development. One hypothesis is that arsenic modulates key cell cycle regulatory proteins and induces transformation events in mammalian cells. In the present proposal, we will study the 3 checkpoints of the human cell cycle in response to low dose arsenic treatment. Arsenic primarily accumulates in the skin. We will study the use of cell-cycle patterns of normal human keratinocytes as well as expression of cell cycle regulatory proteins (cyclins and CDKs) as biomarkers of arsenic toxicity.  We will also investigate the modulation (if any) of various oncogenic pathways such as AKT, MAPK and NFkB in response to arsenic. The signaling pathways modulated by Arsenic will help understand the arsenic toxicity at the molecular level and help make informed decisions about its exposure.