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     

Registrars,Accreditation, and ISO 14001

The International Standardization Organization (ISO) will be publishing the first international environmental management system standard: ISO 14001. The ultimate impact of this standard is subject to heated debate throughout the industrial and environmental communities. This article focuses on one aspect of the standard: the process of certification/registration. ISO 14001 is a voluntary initiative. Companies will need to decide for themselves whether or not to pursue certification. As indicated in Section 1 of ISO 14001, ?This International Standard is applicable to any organization that wishes to

• a) implement, maintain and improve an environmental management system;
• b) assure itself of its conformance with its stated environmental policy;
• c) demonstrate such conformance to others;
• d) seek certification/registration of its environmental management system by an external organization;
• e) make a self determination and declaration of conformance with the standard.”?

As the introduction to ISO 14001 makes clear, ?the specification contains only those requirements that may be objectively audited for certification/registration and/or self declaration purposes.”? Any additional ?guidance…will be contained in other international standards.”? To avoid confusion, these other international standards tend to be called ?guidelines”?. Of particular interest to those associated with the certification and registration of systems to ISO 14001 are the three guidelines for environmental auditing. Officially these are referred to as:

• ISO 14010 - Guidelines for Environmental Auditing - General Principles,
• ISO 14011 - Guidelines for Environmental Auditing - Audit Procedures - Auditing of Environmental Management Systems, and
• ISO 14012 - Guidelines for Environmental Auditing - Qualification Criteria for Environmental Auditors.

     

Exceptionally high levels of multiple mating in an army ant

Most species of social insects have singly mated queens, although there are notable exceptions. Competing hypotheses have been proposed to explain the evolution of high levels of multiple mating, but this issue is far from resolved. Here we use microsatellites to investigate mating frequency in the army ant Eciton burchellii and show that queens mate with an exceptionally large number of males, eclipsing all but one other social insect species for which data are available. In addition we present evidence that suggests that mating is serial, continuing throughout the lifetime of the queen. This is the first demonstration of serial mating among social hymenoptera. We propose that high paternity within colonies is most likely to have evolved to increase genetic diversity and to counter high pathogen and parasite loads.     

Cleanup of fractured rock aquifers: Implications of matrix diffusion

As contamination moves through a fractured rock aquifer, it tends to diffuse from the flowing fracture water into the rock's essentially stagnant pore water. This process tends both to retard a contamination plume's advance through a fractured rock aquifer and to substantially increase the difficulty of purging contamination from the aquifer. A mathematical model has been developed to evaluate the potential impact of this phenomenon upon water quality restoration in fractured rock aquifers. The numerical modeling reveals that cleanup of fractured rock aquifers will, in many cases, require many decades, even centuries, to achieve, particularly where substantial improvements in water quality are sought. The parameters which most strongly govern the degree to which matrix diffusion prolongs the aquifer restoration process are the rock's matrix porosity, fracture spacing, and matrix diffusivity, the chemical identity of the contaminant(s), and the length of time the aquifer has been contaminated.Since sedimentary rocks tend to have both relatively high matrix porosities and matrix diffusivities, it can be particularly difficult to purge contamination from sedimentary rock aquifers. Crystalline rocks, in contrast, typically have lower matrix porosities and matrix diffusivities, and therefore undergo more rapid cleanup. However, even in crystalline rocks, attainment of very high degrees of water quality improvement may be problematic. Numerical modeling also indicates that conventional groundwater pump and treat programs are not likely to be very effective in speeding up aquifer restoration if the rate limiting step in the process is diffusion of contaminants from the rock matrix.