Suchergebnisse

Legislative and managing entities of EU member states face a comprehensive task because the chemical and ecological impacts of contaminated sites on surface waters must be assessed. The ecological assessment is further complicated by the low availability or, in some cases, absence of ecotoxicity data for many of the compounds occurring at contaminated sites. We studied the potential impact of a contaminated site, characterised by chlorinated solvents, sulfonamides, and barbiturates, on benthic macroinvertebrates in a receiving stream. Most of these compounds are characterised by low or unknown ecotoxicity, but they are continuously discharged into the stream by way of a long-lasting source generating longterm chronic exposure of the stream biota. Our results show that taxonomical density and diversity of especially sediment dwelling taxa were reduced by [50 % at the sampling sites situated in the primary inflow zone of the contaminated GW. Moreover, macroinvertebrate communities at these sampling sites could be distinguished from those at upstream control sites and sites situated along a downstream dilution gradient using multidimensional scaling. Importantly, macroinvertebrate indices currently used did not identify this impairment, thus underpinning an urgent need for developing suitable tools for the assessment of ecological effects of contaminated sites in streams.

AbstractGroundwater from the burning ground and landfill of the Longhorn Army Ammunition Plant (LHAAP) in

Texas is currently remediated by pumping the water from an interceptor collection trench system, removing

volatile organic compounds and metals in an ex‐situ treatment process, and discharging the treated water

to a nearby stream. In early 2001, LHAAP's environmental restoration team supplemented the existing

treatment process with an Envirogen biological fluid bed reactor (FBR) to remove the perchlorate prior

to discharge. After a pilot test using site water at Envirogen's New Jersey laboratory, an FBR system

designed to treat 50 gallons of groundwater per minute was installed. The FBR achieved complete perchlorate

removal (< 4 ppb) within three weeks of start‐up (February 2002). The FBR

continues to remove perchlorate to less than 4 ppb. © 2002 Wiley Periodicals, Inc.