Assignment:
Release, Fate & Transport problems. For each case below, use the Transport Checklist to assess the following scenarios. Then:
a) Sketch the scenario (similar to the notes in class). Use pencil to do the sketch, with a red colored pencil/pen to show the movement of the contaminant.
b) List possible exposure considerations (persistence/bioaccumulation, likely populations exposed, future uses and effects)
Q1. A railroad tanker car containing a DNAPL spills it on the tracks. The tracks are situated on a gravel railbed built on a silty sand soil that is 25’ above the water table. Below the water table, an aquifer (3’ thick) of sand/gravel lies above a clay aquiclude. 1500m away is a river; its bottom reaches 2’ into the clay aquiclude. Before the spill can be cleaned up, a heavy rainstorm occurs. There are no populated areas between the tracks and the river, but the river is home to many sensitive aquatic species.
Q2. Lead from historical uncontrolled smelting activities has been deposited on the steep hillsides surrounding the community located in the valley between the hillsides. A creek runs through the community and discharges to a larger river that feeds a lake 50 miles downstream. Logging and the high sulfur air emissions from the smelter destroyed all the trees on the hillsides, but small shrubs are present. The severely lead-contaminated community just completed a massive, costly yard soil removal and house dust abatement program to reduce soil& dust lead levels in the community. Recently heavy rains fell, causing the unremediated soils on the adjacent hillsides to slide into the community. Soils in the community are alluvial and highly heterogeneous, but are mostly silts and sands. Soils on the hillsides are clayey silts.
Q3. A narrow canyon with residential homes scattered within houses a perennial creek. The homes each have their own septic systems. Homes are supplied by wells from a deeper (400’) aquifer. Soils are sandy silts (alluvial) over fractured bedrock and range from 5-20’ above the water table which also supplies the creek. Distances to the creek from septic leach fields range from 10-150’. In addition to nutrients and bacteria from the septic systems, it is expected that many personal care products and pharmaceuticals are discharged in these systems.
Your answer must be, typed, double-spaced, Times New Roman font (size 12), one-inch margins on all sides, APA format.