Phytoremediation of Atrazine by Poplar Trees: Toxicity,Uptake, and Transformation

Toxicity, uptake, and transformation of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] by three species of poplar tree were assessed. Poplar cuttings were grown in sealed flasks with hydrophonic solutions and exposed to various concentrations of atrazine for a period of two weeks. Toxicity effects were evaluated by monitoring transpiration and measuring poplar cutting mass. Exposure to higher atrazine concentrations resulted in decrease of biomass and transpiration accompanied by leaf chlorosis and abscission. However, poplar cuttings exposed to lower concentrations of atrazine grew well and transpired at a constant rate during experiment periods. Poplar cuttings could take up, hydrolyze, and dealkylate atrazine to less toxic metabolites. Metabolism of atrazine occurred in roots, stems, and leaves and became more complete with increased residence time in tissue. These results suggest that phytoremediation is a viable approach to removing atrazine from contaminated water and should be considered for other contaminants.     

The Air Pollution Control Contractorand SMACNA

Over the years JAPCA has directed its attention primarily to the scientist and engineer in their roles as industrial air quality managers, consultants, control officials, educators, researchers, and manufacturers of emission control equipment and air pollution instrumentation. Largely overlooked has been the air pollution control contractor who evolved from the sheet metal industry to become a key figure in the environmental marketplace. Let's look "beyond the flange", as it were, at this contractor, his work, his association, and the professional development opportunities being offered to him.     

Regulatory conflict in the Chicago VOC control program

The study analyzes the performance of an innovative cap-and-trade program designed to make cost-effective reductions of an ozone precursor in Chicago and finds that decentralized market incentives were undermined by the continuance of centralized traditional emission point or command-and-control regulation. The study makes two contributions for urban areas considering this regulatory measure: it shows that using two regulatory measures to achieve one emissions reduction goal can undercut cost-effective emissions trading, and it provides a redesign of the market system that coordinates both regulatory measures for cost-effective control and avoidance of trading problems, such as hot spots and inter-temporal spikes.     

Ideal free distributions under predation risk

 We examine the trade-off between gathering food and avoiding predation in the context of patch use by a group of animals. Often a forager will have to choose between feeding sites that differ in both energetic gain rate and predation risk. The ideal site will have a high gain rate and low risk of predation. However, intake rate will often decrease when the patch is shared with other foragers and it may be optimal for some individuals to feed elsewhere. Within the framework of ideal free theory, we investigate the distribution of foragers that will equalise individual fitness gains. We focus on a two-patch environment with continuous inputs of food. With reference to existing experimental studies, we examine the effects of risk dilution, food input rates and an animal’s expectations of the future. We identify the effect of total animal numbers when one patch is subject to predation risk and the other is safe. Conditions under which the difference in intake rate in the two patches is constant are identified, as are conditions in which the ratio of animals in the two patches is constant. If current conditions do not alter future expectations an increase in input rates to the patches promotes increased use of the risky patch. Yet, if conditions are assumed to persist indefinitely the opposite effect is seen. When both patches are subject to predation risk, dilution of risk favours more extreme distributions, and may lead to more than one stable distribution. The results of these models are used to critically analyse previous work on the energetic equivalence of risk. This paper is intended to help guide the development of new experimental studies into the energy-risk trade-off. Received: 10 February 1995/Accepted after revision: 1 October 1995     

Flocking behaviour of passerines: a dynamic model for the non-reproductive season

Summary The behaviour of a small male passerine bird over a typical winter day is studied by a dynamic programming model. The bird can be either unpaired or paired; an unpaired bird can forage in a flock, forage alone or sing to attract a mate. Foraging increases his reserves, while singing reduces them. The optimal policy and the expected behaviour of birds depend both on time and reserves. The model predicts that birds will flock, especially in the morning, if flocking birds find more food (foraging efficiency), and also more flocking can be expected when the predation risk is lower in a flock (antipredator benefit). Where flocking gives lower variance in food intake, with the same mean (reduced variance benefit), birds with low reserves at the end of the day choose to forage alone (high variance option), while otherwise they are risk-averse and forage in a flock. The cost of flocking increases with time in a day and with the probability of mate attraction through singing. Decisions inevitably involve trade-offs. Where flocking results in antipredator benefit, but also lower foraging gain, birds with low reserves forage alone, but birds with high reserves flock. Offprint requests to: A.I. Houston     

A proposed methodology for measuring incremental environmental benefits from using constructed wetlands to control agricultural non-point-source pollution

A binary response estimation procedure using contingent valuation data is proposed for estimating the incremental environmental benefits associated with the use of constructed wetlands to control agricultural waste-water runoff. The model uses two binary responses per individual while circumventing the non-independence problems associated with follow-up valuation questions. Case study results suggest that the methodology provides a potentially effective means for measuring the non-market benefits of constructed wetlands in addition to water-quality maintenance.1998 Academic Press     

Disaster journalism: fostering citizen and community disaster mitigation,preparedness, response,recovery, and resilience across the disaster cycle

Natural and human‐caused disasters pose a significant risk to the health and well‐being of people. Journalists and news organisations can fulfil multiple roles related to disasters, ranging from providing warnings, assessing disaster mitigation and preparedness, and reporting on what occurs, to aiding long‐term recovery and fostering disaster resilience. This paper considers these possible functions of disaster journalism and draws on semi‐structured interviews with 24 journalists in the United States to understand better their approach to the discipline. A thematic analysis was employed, which resulted in the identification of five main themes and accompanying subthemes: (i) examining disaster mitigation and preparedness; (ii) facilitating recovery; (iii) self‐care and care of journalists; (iv) continued spread of social media; and (v) disaster journalism ethics. The paper concludes that disaster journalism done poorly can result in harm, but done well, it can be an essential instrument with respect to public disaster planning, management, response, and recovery.