An approach to the use of macrophytes for monitoring standing waters

Under the EC Water Framework Directive (WFD), each Member State is required to devise a comprehensive national monitoring programme for surface waters, incorporating hydromorphological, physico-chemical and biological elements. This paper describes one aspect of the biota - the macrophyte flora - to classify standing waters and to monitor their water quality. The evolution of this method is described and suggestions for its future development are made

Upstream Pollution, Downstream Waste Disposal, and the Design of Comprehensive Environmental Policies

Many environmentalists and policymakers are shifting their focus from media-specific pollution problems to product-specific, life-cycle environmental problems. In this paper, we develop a model of production and consumption that incorporates life-cycle environmental externalities—specifically, an upstream manufacturing byproduct, air or water pollution from manufacturing, and downstream solid waste disposal. We then use the model to derive optimal government policies to address all three externalities. We assume throughout that a Pigovian tax on waste disposal is precluded because of the potential for illegal dumping. We then examine four cases: one in which Pigovian taxes on the upstream externalities are feasible, one in which such taxes are infeasible, and two final cases in which the upstream pollutant is subject to one of two different types of regulatory standards. In general, we find that no single instrument can solve multiple problems, contrary to what some observers have suggested. However, we find that there are alternative ways of reaching the social optimum. We also discover that a so-called "integrated" approach to policy appears to be important, no matter what policy options are adopted. And finally, we find that there is only a limited role for product "life-cycle assessments"—enumerations of all of the resources used and pollutants emitted throughout an entire product life-cycle.

Extended Product Responsibility: An Economic Assessment of Alternative Policies

Extended Product Responsibility embodies the notion that agents along a product chain should share responsibility for the life-cycle environmental impacts of the product, including those associated with ultimate disposal. Extended Producer Responsibility is a narrower concept which places responsibility on producers and focuses primarily on post-consumer waste disposal. Manufacturer "take-back" requirements are the policy lever most often associated with Extended Producer Responsibility. In this paper, the authors discuss alternative incentive-based policies that are consistent with the objectives of Extended Product and Producer Responsibility. They argue that an upstream combined product tax and recycling subsidy (UCTS) is generally more cost-effective and imposes fewer transactions costs than the take-back approach. They also consider the strengths and weaknesses of a policy not targeted at producers: unit-based pricing of residential waste collection and disposal. The authors find that this option shows potential for achieving non-trivial reductions in solid waste. Widespread application in the U.S. of a $1.00 charge per 32-gallon bag could reduce total municipal solid waste disposed by approximately 13 percent per year.

The Cost of Reducing Municipal Solid Waste

This paper explores public policies for reduction of municipal solid waste. We parameterize a simple model of waste disposal using supply and demand elasticities from the economics literature and 1990 prices and quantities of recyclable and recycled materials. Using this model, we calculate the waste reduction in response to three public policies: (i) deposit/ refunds, (ii) advance disposal fees, and (iii) recycling subsidies. The results illustrate the effects of the three policies on source reduction and recycling of five recyclable materials that comprise 56 percent of municipal solid waste: aluminum, glass, paper, plastic, and steel. The calculated responses provide information about the cost of reducing municipal solid waste through various policies. This analysis suggests that a 7.5 percent reduction in disposal of the solid wastes in the model might have been optimal in 1990 from a benefit-cost perspective.

Statutory protection of freshwater flora and fauna

The aim of this paper is to summarize the present legislation aimed at protecting freshwater species in Britain, and briefly to review its effectiveness. Some areas have been deliberately omitted, such as fisheries legislation designed to conserve stocks, and the statutory protection of birds associated with fresh waters which forms a large subject area in its own right

Characterization of Amoebae Interactions with Four Non-Pneumophila Legionella Species

Legionella is the causative agent Legionnaires’ Disease and the number one cause of bacterial water-borne outbreaks in the United States. 85% of Legionnaires’ Disease cases are attributed to one species, L. pneumophila. Other virulent Legionella species exist, yet we have limited knowledge of them. Four non-pneumophila species: L. clemsonensis, L. gormanii, L. anisa, and the uncharacterized strain D4482, were chosen to assess host interactions with two species of amoebae, Acanthamoeba polyphaga and A. castellanii. Interactions were assessed with both planktonic, amoebae grown and biofilm Legionella. For planktonic assays, L. pneumophila invaded significantly higher into A. castellanii than into A. polyphaga. Invasion of L. pneumophila was also higher than the four non-pneumophila species in both Acanthamoebae species. Amoebae grown L. clemsonensis showed an increased invasion ability compared to broth grown in A. castellanii. Both A. polyphaga and A. castellanii grazed equally from all Legionella biofilms started from planktonic culture. When amoebae grown bacteria were used to establish biofilms, L. pneumophila, L. gormanii, and L. anisa were grazed at lower amounts by Acanthamoebae than planktonically grown biofilms. Our results suggest that the Acanthamoebae host shows no preference for the Legionella species it consumes and that growth within an amoebae affects the host interaction. Characterization of host-pathogen interactions can aid in creating improved understanding of the microbial ecology and in turn predictive risk assessment for Legionella

The Psychology of Art Appreciation

Some Opinions of Educators Concerning the Teaching of Art Appreciatio