Transport of Sewage Sludge From the 106-Mile Site - Results From an October Survey

Approximately 8 million tons of sewage sludge were disposed of annually at the 106-Mile Deepwater Municipal Sludge Dump Site (106-Mile Site) between 1987 and 1990. Beginning in 1988 and continuing to the present, the focus of monitoring at the 106-Mile Site moved towards improved understanding of the fate of the sludge. A survey conducted in October 1989 was designed to (1) detect the presence of any sludge particles that settle rapidly following disposal, (2) determine if sludge could be detected in the surface waters at locations away from the immediate disposal site, and (3) determine if water quality was degraded, by assessing whether the Environmental Protection Agency's marine water quality criteria were being exceeded.

The survey showed that the sludge does have a rapidly settling component composed of organic floc. mineral grains, and other heavy, gritlike particles, all of which are relatively large. These particles may settle at rates of between 8 and 180 m h^-1 and may reach the sea floor within 1 to 13 days following disposal. Even though a rapidly settling component is present in the sludge, a significant fraction of the sludge was detectable in the form of intact sludge plumes in the upper 35 m of the water column at least 15 km from the Site. in addition, unique tracers of sludge such as xylem tracheids and Clostridium perfringens plus elevated total suspended solids and trace metals concentrations, were found at locations up to 40 km from the Site. the presence of these tracers correspond with in situ transmissometry data suggesting that a fraction of the sludge was remaining in the near-surface waters above the seasonal pycnocline. Concentrations of metals were below EPA chronic marine water quality criteria, which indicates that the water quality downstream of the Site was not impaired. the detection of sludge downstream of the 106-Mile Site is consistent with the southwestward movement of the surface water mass during the survey, as recorded by satellite-tracked surface drifters and current vectors derived from a current meter moored at 100-m depth immediately west of the Site. Near-surface transport was generally towards the southwest at a speed of approximately 22 cm s^-1*.     

STREAM QUALITY IMPACTS OF BEST MANAGEMENT PRACTICES IN A NORTHWESTERN ARKANSAS BASIN1

ABSTRACT: A variety of management options are used to minimize losses of nitrogen (N), phosphorus (P), and other potential pollutants from agricultural source areas. There is little information available, however, to indicate the effectiveness of these options (sometimes referred to as Best Management Practices, or BMPs) on basin scales. The objective of this study was to assess the water quality effectiveness of BMPs implemented in the 3240 ha Lincoln Lake basin in Northwest Arkansas. Land use in the basin was primarily forest (34 percent) and pasture (56 percent), with much of the pasture being regularly treated with animal manures. The BMPs were oriented toward minimizing the impact of confined animal operations in the basin and included nutrient management, dead bird composter construction, and other practices. Stream flow samples (representing primarily base flow conditions) were collected bi-weekly from five sites within the basin from September 1991 through April 1994 and analyzed for nitrate N (NO₃-N), ammonia N (NH₃-N), total Kjeldahl N (TKN), ortho-P (PO₄-P), total P (TP), chemical oxygen demand (COD), and total suspended solids (TSS). Mean concentrations of PO₄-P, TP, and TSS were highest for subbasins with the highest proportions of pasture land use. Concentrations of NH₃-N, TKN, and COD decreased significantly with time (35–75 percent/year) for all sub-basins, while concentrations of other parameters were generally stable. The declines in analysis parameter concentrations are attributed to the implementation of BMPs in the basin since (a) the results are consistent with what would be expected for the particular BMPs implemented and (b) no other known activities in the basin would have caused the declines in analysis parameter concentrations.     

Americium adsorption on the surface of macrophytic algae

Data are presented on the rates at which americium (Am) deposits upon blade surfaces of three benthic algal species (Ulva rigida, Fucus vesiculosus and Gigartina stellata) following short-term exposures (1–6 h). Am is taken up in direct proportion to the ambient radionuclide concentration in sea water. Uptake by the green alga was 3 to 5 times greater than that for the brown and red species. Experimental evidence indicated that Am accumulation is a passive process and that adsorption takes place mainly on the thin outer organic coating of the seaweed. The Am transport coefficients (0·9–4·1 × 10?⁵ Bq cm?² s?¹ per Bq ml?¹ sea water) are quite similar to that previously found for the naturally occurring α-emitter ²¹⁰Po, but are an order of magnitude lower than a plutonium transport coefficient reported in the literature. Release of labelled extracellular products associated with the algal surface coating is considered to be responsible for the rapid loss of Am observed previously in macroalgae and may in fact serve as a mechanism for transferring Am to filter feeding zooplankton.     

Some results from the demonstration of indoor radon reduction measures in block basement houses

Active soil ventilation techniques have been tested in 26 block-wall basement houses in eastern Pennsylvania with significantly elevated indoor radon concentrations, generally above 740 Bq/m³, and the results indicate that radon levels can be reduced substantially often below the U.S. Environmental Protection Agency (EPA) guideline of 148 Bq/m³, if effective suction can be drawn on the soil underneath the concrete slabs of these houses. Such effective suction appears achievable when either: 1) the house has a complete loop of drain tile around its footings for water drainage purposes, and suction is drawn on that loop; or 2) a sufficient number of suction pipes can be inserted at the proper locations into the crushed rock or the soil underneath the slab.     

The Estuarine Component of the Us E.P.A.'S Environmental Monitoring and Assessment Program

The US Environmental Protection Agency's Office of Research and Development has initiated the Environmental Monitoring and Assessment Program (EMAP) to monitor status and trends in the condition of the nation's near coastal waters, forests, wetlands, agro-ecosystems, surface waters, deserts and rangelands. the programme is also intended to evaluate the effectiveness of Agency policies at protecting ecological resources occurring in these systems. Monitoring data collected for all ecosystems will be integrated for regional and national status and trends assessments. the near coastal component of EMAP consists of estuaries, coastal waters, and the Great Lakes. Near coastal ecosystems have been regionalized and classified, and an integrated sampling strategy has been developed. EPA and NOAA have agreed to coordinate and, to the extent possible, integrate the near coastal component of EMAP with the NOAA National Status and Trends Program. A demonstration project was conducted in estuaries of the mid-Atlantic region (Chesapeake Bay to Cape Cod) in the summer of 1990. in 1991, monitoring continued in mid-Atlantic estuaries and was initiated in estuaries of a portion of the Gulf of Mexico. Preliminary results indicate: there are no insurmountable logistical problems with sampling on a regional scale; several of the selected indicators are practical and sensitive on the regional scale; and an efficient effort in future years will provide valuable information on condition of estuarine resources at regional scales.     

Mating systems,parasites and plumage dimorphism in waterfowl

Summary Despite a tendency for males of polygynous bird species to show bright or elaborate plumage, comparative analyses have failed to show any consistent relationship between male brightness or plumage dimorphism and the form of breeding systems. Here we argue that this may be partly because the opportunity for sexual selection varies between species showing serial or seasonal monogamy and life-long monogamy. In waterfowl, both the brightness of male plumage and sexual dimorphism in colouration vary between these categories of monogamy. Other ecological factors related to male brightness or plumage dimorphism include male assistance in protecting young, latitude and an index of parasite sharing. The adaptive significance of these trends is discussed. Offprint requests to: D.K. Scott     

The contribution of forums to rural sustainable development: a preliminary evaluation

This paper assesses the contribution that forums have made in progressing sustainable land use policies and decisions within rural Wales. The examples of Cardigan Bay Forum and Wales Rural Forum are used to show how sustainability has been addressed within their overall agendas. The contemporary debate about sustainable development has provoked a new organizational response with forums visible in many activities and initiatives. The traditional adversarial approach between groups has been replaced by a more sophisticated and complex assemblage of bodies that together create the forum ideal. Consensus, partnership and mutual understanding form the language of this new discourse. However, their presence raises certain key questions as to their role, purpose, representativeness and value in rural resource management debates. These questions have not been considered in the literature, and with the increasing proliferation of forums generally, there is a need to assess whether they are bringing about real and effective change. The two examples reveal clear evidence of forums as agents of change. However, there is considerable tension within both forums, within a climate of financial and membership vulnerability, between the need for involving all legitimate interests and the need to achieve meaningful outcomes for individual members. Such tension goes to the heart of who the two forums actually represent and their resulting actions. The way that these tensions have been reconciled lie at the heart of the forum phenomenon.1998 Academic Press