Impact of Infiltrating Runoff on Ground-Water Recharge Quality Stormwater runoff represents a significant contribution to ground-water recharge. The overall objective of this work is to analyze the impact of infiltrating stormwater runoff on the quality of ground water. We are measuring the quality of recharge from detention basins in the Valley Creek Watershed and measuring pollutant removal as a function of depth beneath the surface. We are also examining filter media that may enhance pollutant removal under infiltration conditions using large- and small-scale laboratory columns. Funding Sources: USGS (through the PA Water Resources Research Center), Drexel Role: PI Students: Laura Klinger, David Burgy, Sarah Hoopes Tools for Site-Specific Biosolids Risk Assessment The goal of this work is to develop a framework for assessing risks from pathogens in land-applied biosolids. We are working to formulate exposure pathway models of pathogen transport and risk assessment models to develop policy recommendations informed by quantitative risk estimates. Funding Source: Water Environment Research Foundation (WERF) Role: Co-PI (P. Gurian, PI) Students: Jingjie Teng, Haibo Zhang Real-Time PCR Detection of Pathogenic Microorganisms in Stormwater and Roof-Harvested Rainwater We are monitoring the microbiological quality of stormwater runoff and roof-harvested rainwater using real-time quantitative PCR. We will test for microbial pathogens and indicator organisms in samples collected through PA and NJ. Funding Sources: USDA, Drexel Role: PI Students: Haibo Zhang, Lauren Reuther Bacterial Migration and Chemotaxis in Porous Media Many of the soil-inhabiting bacteria that degrade chemical contaminants are both motile and chemotactic. Chemotaxis refers to the ability of bacteria to sense pollutant concentration gradients in water and preferentially swim toward regions of high pollutant concentration. We are studying bacterial chemotaxis to common environmental contaminants, how chemotaxis affects bacterial migration toward these contaminants in soil, and how chemotaxis impacts biodegradation of organic contaminants in polluted ground-water systems. Funding Sources: Louis and Bessie Stein Foundation, Drexel University Role: PI Students: Rajveer Singh, Minhua Xu Analysis of Heavy Metals in Runoff from Scrap Metal Facilities We are analyzing runoff samples from scrap metal facilities for concentrations of lead, nickel, chromium and copper, as well as standard stormwater quality parameters. Funding Sources: Drexel STAR program, Delaware Riverkeeper Role: Co-PI with F. Montalto Students: Lauren Reuther, Danny Culbert Bacterial Viability and Response to Environmental Stress Although bacterial communities are remarkably adaptable to dynamic environmental conditions, many anthropogenic contaminants are toxic to bacteria. We study the viability of bacteria over time when exposed to environmental stresses, including chemical contaminants and nanoparticles. Funding Source: Drexel University Students: Rajveer Singh, Kim DiGiovanni, Sheri Joe