CHEMICAL MEASUREMENT OF MEAN TEMPERATURE

Mean temperature is employed universally as an index to the energy status of the environment, and to indicate probable reaction rates of physical and biological processes in nature. A versatile chemical method of temperature integration, based on the temperature dependence of sucrose hydrolysis, has been tested in central Pennsylvania. The chemical technique (after Pallmann) permits economical mass sampling of air, water, and soil temperatures in situations where conventional methods are too expensive or otherwise unsatisfactory. Short-wave radiation effects are negligible since the sensing elements are transparent. Repeatability is excellent: in field tests duplicate sensors yield the same mean temperature ± 0.02°C. Non-linearity of sensor response has been resolved, and the data can be related directly to measurements obtained in standard climatological networks. The technique can be used to good advantage in a variety of hydrological investigations, including evaporation, consumptive-use, and them pollution studies.     

GOALS IN WASTEWATER TREATMENT1

Within a few years all domestic wastewater effluents in the United States will be subjected to a minimum of a properly operated primary and secondary treatment process. This implies a very high degree of removal of the more readily biologically degradable material as measured by the BOD test. This practice will to a large degree negate the value of the BOD test as a pollution parameter. Organic carbon appears to be a more suitable means for determining the strength of a wastewater or for controlling the operation of physical and chemical treatment processes. Studies were conducted to determine the effect of time of passage on the ratio of organic carbon to BOD, COD and carbohydrate. The ratio was found to vary with both time and the state of the sample. The carbon content was reduced to a lesser degree than the other parameters. Organic carbon content appears to correlate better with COD than with BOD. The efficiency of a chemical precipitation process can be determined on the basis of organic carbon removal.     

Cascading ecological effects of low-level phosphorus enrichment in the Florida everglades

Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 microg L(-1) above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.     

Radioactive materials in biosolids: national survey, dose modeling, and publicly owned treatment works (POTW) guidance

The Nuclear Regulatory Commission (NRC) announced the availability of three new documents concerning radioactive materials in sewage sludge and ash from publicly owned treatment works (POTW). One of the documents is a report presenting the results of a volunteer survey of sewage sludge and ash samples provided by 313 POTWs. The second document is a dose modeling document, using multiple exposure pathway modeling focused on a series of generic scenarios, to track possible exposure of POTW workers and members of the general public to radioactivity from the sewage sludge or ash. The third document is a guidance report providing recommendations on the management of radioactivity in sewage sludge and ash for POTW owners and operators. This paper explains how radioactive materials enter POTWs, provides criteria for evaluating levels of radioactive material in sludge and ash, and gives a summary of the results of the survey and dose modeling efforts.     

Decadal change in vegetation and soil phosphorus pattern across the Everglades landscape

Wetlands respond to nutrient enrichment with characteristic increases in soil nutrients and shifts in plant community composition. These responses to eutrophication tend to be more rapid and longer lasting in oligotrophic systems. In this study, we documented changes associated with water quality from 1989 to 1999 in oligotrophic Everglades wetlands. We accomplished this by resampling soils and macrophytes along four transects in 1999 that were originally sampled in 1989. In addition to documenting soil phosphorus (P) levels and decadal changes in plant species composition at the same sites, we report macrophyte tissue nutrient and biomass data from 1999 for future temporal comparisons. Water quality improved throughout much of the Everglades in the 1990s. In spite of this improvement, though, we found that water quality impacts worsened during this time in areas of the northern Everglades (western Loxahatchee National Wildlife Refuge [NWR] and Water Conservation Area [WCA] 2A). Zones of high soil P (exceeding 700 mg P kg(-1) dry wt. soil) increased to more than 1 km from the western margin canal into the Loxahatchee NWR and more than 4 km from northern boundary canal into WCA-2A. This doubling of the high soil P zones since 1989 was paralleled with an expansion of cattail (Typha spp.)-dominated marsh in both regions. Macrophyte species richness declined in both areas from 1989 to 1999 (27% in the Loxahatchee NWR and 33% in WCA-2A). In contrast, areas well south of the Everglades Agricultural Area, induding WCA-3A and Everglades National Park (ENP), did not decline during this time. We found no significant decadal change in plant community patterns from 1989 and 1999 along transects in southern WCA-3A or Shark River Slough (ENP). Our 1999 sampling also included a new transect in Taylor Slough (ENP), which will allow change analysis here in the future. Regular sampling of these transects, to verify decadal-scale environmental impacts or improvements, will continue to be an important tool for long-term management and restoration of the Everglades.     

Commercialization of Dredged-Material Decontamination Technologies

This article describe a unique federal project aimed at the commercialization of different technologies for the decontamination of dredged material. The project is organized so that commercialization is achieved in a seamless way, starting with validation at the bench- and pilot-scale levels, and ending with the actual construction of operational facilities. This is the first integrated sediment decontamination program in which a step-wise bench-scale validation process of innovative/emerging technologies will scale-up to a production-scale facility capable of processing up to 375,000 m³ of dredged material per year. The need to develop public-private partnerships for the facility construction is emphasized as a way of obtaining adequate finding for capital and operating costs during the startup time of the commercialization process. It is expected that the end result of the project work will be the creation of economically-viable, self-sustaining decontamination technology companies.     

Prioritizing R&D for the U.S. Department of Energy's Weapons Complex Clean-Up

Prioritizing the U.S. Department of Energy's (DOE's) targeted R&D program supporting weapons-complex clean-up has been problematic. Considering issues common to all R&D evaluation, linking R&D prioritization to clean-up project prioritization, the latter aligned with institutional goals, offers a pragmatic solution. This method is illustrated with results of a clean-up prioritization model of DOE's Oak Ridge National Laboratory site.     

Watershed-based management strategies for the prevention and abatement of polluted agricultural runoff

An increase in the average size of individual livestock production operations coupled with local and regional concentrations of these operations tend to increase negative environmental impacts in many watersheds. Environmental compliance strategies developed by the Texas Institute for Applied Environmental Research (TIAER) can be applied to reduce the negative impacts caused by livestock production and other types of agricultural activities. Further, the Institute's planned intervention/micro-watershed approach may provide the foundation for comprehensive solutions to environmental problems within a broad ecosystem management context.