Northeast Creek TMDL: The Health and Economic Impact of High Concentrations of Fecal Coliform

Forty years after the passage of the Clean Water Act, 40% of the nation's waterways still do not meet water quality standards, In order to achieve the Clean Water Act's goals, the Environmental Protection Agency implemented the Total Maximum Daily Load (TMDL) program. A TMDL is a quantitative representation of pollution contribution from point and non point sources and is often used as part of watershed restoration plans. Watershed restoration plans involve implementing strategies and policies that can effectively achieve water quality standards; since TMDLs only provide information about the sources, they're use is limited. The addition of a health risk component identifies the costs from current contaminant levels, and the benefits from achieving compliance standards, thus allowing policy makers to choose the most efficient and cost effective restoration strategies. This research addresses the impact of high fecal coli from concentrations in Northeast Creek, identifying both an economic and health impact, associated with either the baseline (no policy) or establishment of a TMDL.Master of Science in Public Healt

Nanosize Titanium Dioxide Stimulates Reactive Oxygen Species in Brain Microglia and Damages Neurons in Vitro

BackgroundTitanium dioxide is a widely used nanomaterial whose photo-reactivity suggests that it could damage biological targets (e.g., brain) through oxidative stress (OS).ObjectivesBrain cultures of immortalized mouse microglia (BV2), rat dopaminergic (DA) neurons (N27), and primary cultures of embryonic rat striatum, were exposed to Degussa P25, a commercially available TiO2 nanomaterial. Physical properties of P25 were measured under conditions that paralleled biological measures.FindingsP25 rapidly aggregated in physiological buffer (800–1,900 nm; 25°C) and exposure media (~ 330 nm; 37°C), and maintained a negative zeta potential in both buffer (–12.2 ± 1.6 mV) and media (–9.1 ± 1.2 mV). BV2 microglia exposed to P25 (2.5–120 ppm) responded with an immediate and prolonged release of reactive oxygen species (ROS). Hoechst nuclear stain was reduced after 24-hr (≥100 ppm) and 48-hr (≥2.5 ppm) exposure. Microarray analysis on P25-exposed BV2 microglia indicated up-regulation of inflammatory, apoptotic, and cell cycling pathways and down-regulation of energy metabolism. P25 (2.5–120 ppm) stimulated increases of intracellular ATP and caspase 3/7 activity in isolated N27 neurons (24–48 hr) but did not produce cytotoxicity after 72-hr exposure. Primary cultures of rat striatum exposed to P25 (5 ppm) showed a reduction of immunohistochemically stained neurons and microscopic evidence of neuronal apoptosis after 6-hr exposure. These findings indicate that P25 stimulates ROS in BV2 microglia and is nontoxic to isolated N27 neurons. However, P25 rapidly damages neurons at low concentrations in complex brain cultures, plausibly though microglial generated ROS