Melinda Lalor

The Role of Pollution Prevention in Stormwater Management

Around the nation, there is growing interest in the development and use of environmentally sensitive construction materials as a low-cost component to stormwat…

Wet-Weather Pollution from Commonly-Used Building Materials

Development in sensitive watersheds continues to pose environmental problems for receiving waters. One contributor to the long-term pollution of sensitive waterways is building and construction materials. However, the long-term effect of many building materials on the environment has not been quantified. Prior testing of these materials in the laboratory has indicated that the potential for release (primarily nutrients, lighter hydrocarbons, pesticides, and metals) is significant. Additional testing for metals’ release from aged roofing panels also has shown that the potential for pollutant release still exists after 60 years of exposure to the environment. The data that is missing from a complete evaluation of specific building materials is behavior over the lifespan of the material, including the critical period of initial exposure. This paper provides an overview of the limited literature available on the subject, results from laboratory testing of common building materials and aged roofing panels, and an overview of the next phase of needed research.

Pollutant Potential from Building Materials: Laboratory and Field Evaluations

Development in sensitive watersheds continues to pose environmental problems for receiving waters. Materials, such as galvanized metal, concrete, asphalt and wood products, may release pollutants into urban runoff and snowmelt; however, the long term effect of commonly-used building materials on the environment has not been quantified. Laboratory testing on common roofing materials indicated that the potential for release (primarily nutrients, hydrocarbons, pesticides, and metals) is substantial. Further testing on painted, galvanized roofing tiles that were exposed to the Pennsylvania climate for 60+ years indicated that material continued to be released from these panels – indicating a deeper reservoir than simply the loss of a sacrificial surface coating. The ongoing research project involves testing a variety of construction materials (roofing materials, treated and untreated woods) to determine their long-term pollutant release after typical installation and exposure to the weather. The goal is to develop a better understanding of how the aging and exposure processes will impact the release over time. Understanding the ‘release vs. time’ of a pollutant from a material will be crucial for translating the laboratory results to the actual environment and to developing predictive models for evaluating new materials for their pollutant potential.

EFFECT OF CANOPY COVER ON THE VOLUME OF RAIN THROUGHFALL

Stormwater runoff has become increasingly difficult for municipalities to manage as areas experience development. This increase in residential and commercial development has led to a substantial reduction in the natural canopy cover, and post-development plantings have not begun to replace the loss. This study was carried out to establish the extent to which post-development rain throughfall, and resulting runoff, could be reduced by leaving canopy cover in place. The study compared the volume and intensity of rain that reached the ground in an open area (no canopy cover) versus two areas with intact canopy covers. Rain gauges were placed in a parking lot, and in wooded areas in an environmentally-friendly development in Shelby County, Alabama. Rain was measured for a period of twelve consecutive months and rain throughfall was compared between the sites by season (Spring/Summer vs. Fall/Winter) and by rainfall depth. The sites were sufficiently close to each other to assume that the rainfall characteristics were the same between the sites in terms of the intensity and the variation of intensity and volume during the storm. Investigation of the relationship between the amount of throughfall on an area without canopy cover and with canopy showed that, for these sites, even in an area with high rainfall intensities, canopy cover could be expected to reduce the total throughfall by approximately 13.5% during spring and summer months. No significant results were seen for intensity but this evaluation was limited by the study techniques. The results of this project indicated that in areas where reducing stormwater runoff is desirable, there is a significant, measurable advantage to preserving the natural canopy on a site wherever possible. The reduction of the rainfall amount reaching the ground reduces the amount of runoff that has to be managed by the developer and the property owner. It also could be expected to reduce the amount of erosion being generated from a site.

Strategies/Guidance for Managing Stormwater: Infiltration vs. Surface Water Discharge

Past studies have identified urban runoff as a major contributor to the degradation of many urban streams and rivers. The management of municipal stormwater runoff necessitates decisions as to whether the disposal of runoff should be through infiltration, surface discharge or a combination of the two. Typically, this management is addressed through the use of best management practices (BMPs) at the site in question or at a location in the conveyance system prior to discharge to a receiving water body either above or below ground. These BMPs may be selected based on site-specific conditions and discharge requirements, but often they are selected based on past history of what has worked in the municipality, the experience of the planners with specific BMPs, and regulatory requirements on the federal, state and local level. The primary objective of this project is to develop a preliminary guidance document for municipal planners and engineers to use when they are evaluating their various stormwater management options, especially as they balance master planning requirements for their specific localities/regions and regulatory requirements. The preliminary guidance manual will propose a simple decision tree analysis structure to guide planners through the steps needed to determine the requirements for infiltration as well as the water-quality standards and quality of stormwater that may inhibit the use of infiltration.

Effect of Mycobacterium Sp. Strain CH1 and Mycobacterium Sp. Strain CH2 on the Degradation of Four-Ring Creosote Compounds

Abstract The influence of nutrients, Mycobacterium sp. strain CH1 and Mycobacterium sp. strain CH2 on the degradation of aged creosote hydrocarbon contaminants was investigated. The Mycobacterium sp. strain CH2 showed the highest positive influence on the degradation of three- and four-ring PAH compounds. The addition of Mycobacterium sp. strain CH1 had the second highest measured positive influence on the degradation of four-ring compounds. Soluble nitrogen and phosphorus also increased the degradation of aged creosote compounds in the contaminated soil. The addition of bacteria decreased the number of measured bacterial species, indicating competition for limited nutrients in the soil.