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TOXIC POLLUTANTS IN URBAN WET-WEATHER FLOWS: AN OVERVIEW OF THE MULTI-MEDIA TRANSPORT, IMPACTS, AND CONTROL MEASURES
Citation:
Fan*, C Y., R Field*, D Sullivan*, AND D Lai*. TOXIC POLLUTANTS IN URBAN WET-WEATHER FLOWS: AN OVERVIEW OF THE MULTI-MEDIA TRANSPORT, IMPACTS, AND CONTROL MEASURES. Proceedings of the World Water & Environmental Resources Congress, Orlando, FL, 5/20-24/01.
Description:
This paper presents an overview of the transport of toxic pollutants through multiple media and drainage systems in the urban watershed during wet-weather periods. It includes the origin of the toxic substances; their transport via atmospheric depositon, overland washoff, and urban sewer systems; and, their impacts on both surface and ground waters. During dry-weather periods, incompletely combusted hydrocarbons from automobiles combine with atmospheric particulates from a host of other sources and deposit on urban streets and other urban surfaces. During a storm event, these solids, in addition to solids from industrial and commercial parking lots, material storage areas, and vehicular service stations are washed off by surface runoff and drined into either separate storm sewer or combined sewer systems. Field studies have identified that a major portion of hazardous waste priority pollutants including benzene, polynuclear aromatic hydrocarbons, (PAHs), polychlorinated biphenyls (PCBs), pesticides, and heavy metals (e.g., arsenic, cadmium, chromium, copper, lead, mercury, and zinc) contained in urban stormwater runoff are in particulate form or sorbed onto particles. These stormwater particulate pollutants contribute significant toxicity to receiving waters. Mortality, epidermal lesions, or fin erosion can occur in fish and other aquatic life forms that are exposed to these toxic suspended solids and sediments. This paper discusses methods for intercepting the cross-media transport of toxic constituents in the urban environment, including best management practices to control surface runoff pollution; steeper sewer slop0eage and improved pipe bottom shapes to maintain high-velocity solids-carrying capacity during low-flow periods; and upstream sewer flushing and sediment trapping to reduce clogging and sediment in sewers.