Regulation of Indirect Sources

The Division of Air Pollution Control, Illinois Environmental Protection Agency, has conducted an ambient air quality monitoring project focusing on carbon monoxide levels in and around several indirect sources. An analysis of the data indicates that highway-type pollutant emissions have the greatest impact on receptors in the vicinity of indirect sources. This implies that the principal, localized constraint on the siting of indirect sources will be the carbon monoxide generated on public roadways servicing those indirect sources. Clearly, adequate procedures must be developed to link such highway-type emissions to pollutant concentrations. An area-source model and a line-source model were tested using the data generated during the monitoring project. Favorable results were achieved using the line-source model. The proper siting of indirect sources involves the allocation of roadway capacity by the governmental units responsible for transportation network design, working in conjunction with regional planning bodies. A regulatory structure is suggested which emphasizes a regional approach, and an example of an air quality allocation scheme is given. The methodology is applicable to all automotive air pollutants although, in general, localized sensitivity is lost for N0₂ and photochemical oxi-dants.     

Exchange-rate economics for the resources sector

The paper provides an account of aspects of exchange-rate economics that are of particular relevance to the resources sector. The issues discussed include exchange-rate volatility and the risk management practices used to deal with it, the role of productivity differences across countries, and the impact of a booming resources sector on the country's exchange rate. The discussion is organized around a simple stylized model that emphasizes the quantity theory of money and purchasing power parity as a long-run link between prices and exchange rates.     

Biomonitors and the assessment of ecological impacts: distribution of herbivorous epifauna in contaminated macroalgal beds

We determined metal contents of co-occurring algae Padina crassa and Sargassum sp. in Port Jackson (Australia), and relationships between metal levels and the abundance of epifaunal amphipods. Copper, lead and zinc concentrations were amongst the highest yet recorded in these algae. Copper, manganese and lead concentrations were far greater in P. crassa than Sargassum sp., possibly due to the low growth of P. crassa in proximity to contaminated sediments. However, in manipulative experiments the proximity of algae to sediments did not explain these differences. The abundance of herbivorous amphipods correlated negatively with the copper content of P. crassa, but not with the lower concentrations in Sargassum sp. The greater contamination of P. crassa led to patchy distributions of metals in algal beds and recolonisation experiments showed Sargassum sp. acts as a refuge from contaminants for epifauna. The contamination of macroalgae may pose threats to epifauna in harbours around the world.     

Nature and nurture: Environmental isotope story of the River Rhine

The total dissolved load of the Rhine river increases downstream due to the combined impact of natural and pollution loads. The natural background, controlled by geology, is soon swamped by pollution, particularly from salt and coal mining activities in Alsace and the Ruhr area. The Rhine is also a net source of CO₂ from oxidation of excess organic productivity that is fuelled by nutrient pollution, a problem even more serious for some of its tributaries.Also Derry/Rust Research Group, Ottawa-Carleton Geoscience Center, University of Ottawa, Ottawa, Canada KIN 6N5     

Evaluating forest management practices using a GIS-based cellular automata modeling approach with multispectral imagery

The objective of this study was to develop an integrated geographic information system (GIS) cellular automata (CA) model for simulating insect-induced tree mortality patterns in order to evaluate the influence of different forest management activities to control insect outbreaks. High-resolution multispectral images were used to determine susceptibility of trees to attack, whereas the GIS-based CA model simulated the effectiveness of clear-cuts and thinning practices for reducing insect-induced tree mortality. The results indicate that thinning susceptible forests should be more effective than clear-cutting for reducing tree loss to insect outbreaks. This study demonstrates the benefits of an integrated approach for understanding and evaluating forest management activities and expresses the need for spatial analysis and modeling for improving forest management practices.