Photochemical smog effects in mixed conifer forests along a natural gradient of ozone and nitrogen deposition in the San Bernardino Mountains

Toxic effects of photochemical smog on ponderosa and Jeffrey pines in the San Bernardino Mountains were discovered in the 1950s. It was revealed that ozone is the main cause of foliar injury manifested as chlorotic mottle and premature needle senescence. Various morphological, physiological and biochemical alterations in the affected plants have been reported over a period of about 40 years of multidisciplinary research. Recently, the focus of research has shifted from studying the effects of ozone to multiple pollutant effects. Recent studies have indicated that the combination of ozone and nitrogen may alter biomass allocation in pines towards that of deciduous trees, accelerate litter accumulation, and increase carbon sequestration rates in heavily polluted forests. Further study of the effects of multiple pollutants, and their long-term consequences on the mixed conifer ecosystem, cannot be adequately done using the original San Bernardino Mountains Air Pollution Gradient network. To correct deficiencies in the design, the new site network is being configured for long-term studies on multiple air pollutant concentrations and deposition, physiological and biochemical changes in trees, growth and composition of over-story species, biogeochemical cycling including carbon cycling and sequestration, water quality, and biodiversity of forest ecosystems. Eleven sites have been re-established. A comparison of 1974 stand composition with data from 2000 stand composition indicate that significant changes in species composition have occurred at some sites with less change at other sites. Moist, high-pollution sites have experienced the greatest amount of forest change, while dryer low-pollution sites have experienced the least amount of stand change. In general, ponderosa pine had the lowest basal area increases and the highest mortality across the San Bernardino Mountains.     

Removing color and chlorinated organics from pulp mill bleach plant effluents by use of flyash

Color and chemical oxygen demand (COD) in bleach plant effluents are of concern. Acidified flyash can effectively remove both color and COD from caustic bleach plant effluents. Equally effective, but quicker and easier, is to acidify the effluent to approximately pH 1 and use untreated flyash. Based on maximum color removal, the required contact time is short, about 10 min, and the optimum ash dosage is that amount which raises the pH of the final effluent to about 5. Sufficient color removal is obtained to easily meet Maine's color regulations. Preliminary tests on samples of deionized water spiked with two arochlors of PCB showed high removal efficiency.The major cost of implementing and operating the cleanup procedure will be the cost of the required acid. This might be minimized by using some of the acidic (chlorine) effluent to lower the pH of the caustic effluent. This will, however, lead to less color reduction, and an unknown effect on the COD.     

Reactions to physically dangerous work: A conceptual and empirical analysis

This study addressed some conceptual issues central to understanding human reactions to dangerous settings and empirically explored the meaning of physically dangerous work in three different occupational groups (street patrol officers, n=96; investigators, n=21; and clerical and support service workers, n=60) practicing in the same organizational setting (city police department). Objective hazards, estimated with occupational risk statistics, explained 56 per cent of the variation in experienced physical danger which, in turn, significantly heightened emotional exhaustion, dissatisfaction with pay, and disaffection from the employing organization, in the street patrol officer group only, perceived physical danger significantly correlated with task variety, task significance and feedback. The data are interpreted to mean that for street patrol officers, experienced physical danger adds a modicum of enrichment and significance to the work itself. One theme of the analysis is that potentially stigmatic features of the work can be transformed into socially meaningful illusions that enhance the personal dignity of the performer (cf. Hughes, 1958). However, the dominant theme is that physically dangerous work produces fear and related affective distress. Further research on this topic is recommended because of the affective and behavioral consequences of perceived physical danger and also because definitions and meanings of dangerous work are socially, politically and morally important.     

NATIONWIDE REGRESSION MODELS FOR PREDICTING URBAN RUNOFF WATER QUALITY AT UNMONITORED SITES1

ABSTRACT: Regression models are presented that can be used to estimate mean loads for chemical oxygen demand, suspended solids, dissolved solids, total nitrogen, total ammonia plus nitrogen, total phosphorous, dissolved phosphorous, total copper, total lead, and total zinc at unmonitored sites in urban areas. Explanatory variables include drainage area, imperviousness of drainage basin to infiltration, mean annual rainfall, a land-use indicator variable, and mean minimum January temperature. Model parameters are estimated by a generalized-least-squares regression method that accounts for cross correlation and differences in reliability of sample estimates between sites. The regression models account for 20 to 65 percent of the total variation in observed loads.     

The Development and Implementation of Indicators of Ecosystem Health in the Great Lakes Basin

This paper describes a process for the selection of a suite of ecosystem health indicators for the Great Lakes, as called for in the Great Lakes Water Quality Agreement. The paper also presents some preliminary data on status and trends in ecosystem components based on those indicators. The indicator selection process was carried out by over 150 scientists and managers from both Canada and the USA, and involved the presentation of the proposed indicators at the State of the Lakes Ecosystem Conferences (SOLECs). An open period for comment followed the conferences where input from scientists involved in Great Lakes programs was received. The suite of indicators will, over time, present information in an understandable format that will allow for more informed management decisions.     

Spatial Relationships Between Water Quality and Pesticide Application Rates in Agricultural Watersheds

Pesticide applications to agricultural lands in California, USA, are reported to a central data base, while data on water and sediment quality are collected by a number of monitoring programs. Data from both sources are geo-referenced, allowing spatial analysis of relationships between pesticide application rates and the chemical and biological condition of water bodies. This study collected data from 12 watersheds, selected to represent a range of pesticide usage. Water quality parameters were measured during six surveys of stream sites receiving runoff from the selected watershed areas. This study had three objectives: to evaluate the usefulness of pesticide application data in selecting regional monitoring sites, to provide information for generating and testing hypotheses about pesticide fate and effects, and to determine whether in-stream nitrate concentration was a useful surrogate indicator for regional monitoring of toxic substances. Significant correlations were observed between pesticide application rates and in-stream pesticide concentrations (p < 0.05) and toxicity (p < 0.10). In-stream nitrate concentrations were not significantly correlated with either the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.30). Neither total watershed area nor the area in which pesticide usage was reported correlated significantly with the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.14). In-stream pesticide concentrations and effects were more closely related to the intensity of pesticide use than to the area under cultivation.     

Integrity and Rights of Plants: Ethical Notions in Organic Plant Breeding and Propagation

In addition to obviating the use of synthetic agrochemicals and emphasizing farming in accordance with agro-ecological guidelines, organic farming acknowledges the integrity of plants as an essential element of its natural approaches to crop production. For cultivated plants, integrity refers to their inherent nature, wholeness, completeness, species-specific characteristics, and their being in balance with their (organically farmed) environment, while accomplishing their “natural aim.” We argue that this integrity of plants has ethical value, distinguishing integrity of life, plant-typic integrity, genotypic integrity, and phenotypic integrity. We have developed qualitative criteria to ethically evaluate existing practices and have applied these criteria to assess whether current plant breeding and propagation techniques violate the integrity of crop plants. This process has resulted in a design of a holistic, scientific approach of organic plant breeding and seed production. Our evaluation has met considerable criticism from mainstream (crop) scientists. We respond to the following questions: (1). Can ethics be incorporated into objective crop sciences? (2). What is the nature of the intrinsic value of plants in organic farming? We argue that criteria to take integrity into account can only be assessed from a holistic perspective and we show that a holistic approach is needed to design such ethical notions in a consistent way. The ethical notions have been further elaborated by formulating human responsibility and respect towards crop plants. Responsibility and respect can only be shown by providing crop plants the right to be nurtured and to express natural behavior at all levels of integrity.     

Scaling the quality of teammates' mental models: equifinality and normative comparisons

We tested the impact of teammates' team and task mental model sharedness on team processes and performance using 70 undergraduate teams that completed a series of missions on a PC‐based flight simulator. Moreover, we considered how the quality of mental models might moderate such relationships. Team processes were found to partially mediate the relationship between task mental model sharedness and team performance. Although team mental model sharedness failed to exhibit a significant linear relationship with team processes or performance, it did evidence a multiplicative relationship as moderated by the quality of those models. Team processes and performance were better among teams sharing higher‐quality team mental models than among teams evidencing less sharedness or who had lower‐quality models. Again, team processes partially mediated these relationships. Results are discussed in terms of the equifinality of mental model quality and applications to various team environments. Copyright © 2005 John Wiley & Sons, Ltd.