Effect of airborne bromoxynil-octanoate and metribuzin on non-target plants

The present study was conducted to determine the effects of airborne herbicides on the photosynthesis and growth of non-target plants. Sunflowers at different growth stages were used as test plants and exposed for 24 h in a wind tunnel to a range of concentrations of bromoxynil-octanoate and metribuzin. The quantum yield (phiPSII) and the dry weight were used as response parameters. Results indicate that young sunflower plants are affected by sublethal concentrations of both herbicides, whereas metribuzin proved to be more phytotoxic. Bromoxynil-octanoate and metribuzin concentrations > 0.265 and >0.135 microg/m(3) impair the photosynthetic activity of exposed leaves and concentrations >0.780 and >0.641 microg/m(3) of leaves developed after exposure. Effects on dry weight indicate that younger plants were more susceptible, whereby the response to metribuzin proved to be more dependent on growth stage. Based on these results and considering herbicide concentrations in ambient air, there is a reasonable probability that non-target plants are temporarily at risk of being affected.     

Disadvantaged consumers — can planning respond?

The development of new forms of retailing has brought material advantage to a majority of the population, in terms of greater choice, comfort and cheapness in shopping. These benefits are greatest in supermarkets and hypermarkets. However, these outlets are not evenly distributed over the urban area when compared to smaller, traditional stores. As a result the population has varying degrees of access to them. As strong disparities in levels of income, and mobility already exist, concern has been expressed over the growing inequalities between the poorer, minority sections of the population, and the rest. This paper identifies groups of consumers who can be described as ‘disadvantaged’ in terms of shopping and looks at the spatial implications of consumer deprivation and examines possible solutions to these problems.     

Better environmental future in Europe through environmental auditing?

environmental auditing must be rejected if the aim is to make companies introduce a specific management concept. Rather, it is preferable to leave the search for effective environmental protection strategies to the competitive system, especially since the criteria for environment-oriented management in the European Community audit proposal are without substance. Environmental auditing can, however, assume a complementary function in the framework of an overall environmental policy if it is designed as an information tool with which companies provide information on the development of environmental problems deriving from their manufacturing processes and products. However, the model required to establish a framework of quantity and evaluation criteria is not available. Further, auditing does not cover products. Similarly, there are no proposals defining the evaluation procedure for ecological resource scarcity. Thus, the attempt of the Commission of the European Communities to create the elementary prerequisites for consistent and verifiable environmental auditing in the corporate sector has failed.     

Decision analysis of polluted sites — a fuzzy set approach

A decision analysis based model (DAPS 1.0, Decision Analysis of Polluted Sites) has been developed to evaluate risks that polluted sites might pose to human health. Pollutants present in soils and sediments can potentially migrate from source to receptor(s), via different pathways. In the developed model, pathways are simulated via transport models (i.e. groundwater transport model, runoff-erosion model, air diffusion model, and sediment diffusion, and resuspension model in water bodies). Humans can be affected by pollutant migration through land and water use. Health risks can arise from ingestion of and dermal contact with polluted water and soil, as well as through inhalation of polluted air. Quantitative estimates of risks are calculated for both carcinogenic and non-carcinogenic pollutants. Being very heterogeneous, soil and sediment systems are characterized by uncertain parameters. Concepts of fuzzy set theory have been adopted to account for uncertainty in the input parameters which are represented by fuzzy numbers. An inference model using fuzzy logic has been constructed for reasoning in the decision analysis.     

Microbial uptake of dissolved organic matter in Mcmurdo Sound,Antarctica

The distribution and activity of bacterioplankton, and the turnover of dissolved organic matter (DOM) were examined in McMurdo Sound, Antarctica. On the eastern side of the Sound, bacteria averaged 6.5×10⁸ l^-1, and turnover rates of dissolved adenosine triphosphate, D-glucose and l-leucine averaged 16, 116 and 124 h, respecitvely. These molecules as well as thymidine were taken up maximally from 0° to 5°C and near-maximally from -1.5° to 0°C, indicating bacterial adaptation to rapid turnover of dissolved organic matter at the ambient temperature. On the west side of the Sound, bacteria averaged only 0.65×10⁸ l^-1, and turnover times for adenosine triphosphate, D-glucose and lleucine averaged 59, 20454, and 3070 h, respectively. Total microbial adenosine triphosphate (an indicator of total microbial biomass) and chlorophyll a were also much lower at the western than at the eastern side stations. Moreover, no primary production could be detected at one western side station (New Harbor). Thus, in McMurdo Sound, the western side is highly oligotrophic, but the eastern side has an abundant active bacterioplankton, comparable to that of temperate coastal waters.Communicated by N. Holland, La Jolla     

Sugar concentration and the structure of the sunbird's song

Summary The full song of the yellow-bellied sunbird (Nectarinia venusta) comprises distinct phrases, which retain their typical three-part structure and temporal organization regardless of the concentration of the sucrose solution provided. However, the sugar concentration does affect the types of elements that make up the initial part of the phrase and the number of elements in the terminal part. Several types of elements may be produced either as separate calls or as components of the initial part of the phrase; as the concentration decreases, at least two of these element types occur progressively more often in the phrases, taking the place of others.     

Cholestyramine enhances fecal elimination of pentachlorophenol in rhesus monkeys

The effect of cholestyramine in the daily diet upon the excretion of pentachlorophenol with the feces was studied in the rhesus monkey. The treatment increased fecal elimination of pentachlorophenol and/or metabolites up to 9- to 14-fold over a six-day period. At the same time urinary excretion was reduced 2- to 6-fold. The data suggest that cholestyramine interrupts the enterhepatic circulation of PCP and/or metabolites thus indicating its possible usefulness in preventing toxicity of PCP that otherwise may occur due to reabsorption of biliary PCP and/or metabolites.     

Ultraviolet and chlorine disinfection of mycobacterium in wastewater: effect of aggregation.

Mycobacteria naturally aggregate in water, a characteristic that may serve to protect them against disinfection in wastewater. Secondary effluent was spiked with Mycobacterium terrae (M. terrae), sequentially filtered through 100-, 41-, and 20-microm nylon filters to partition aggregate sizes, confirmed using particle-size analysis and microscopy. Each sample was exposed to doses of UV light (10 to 60 mJ/cm2 at 254 nm) and free chlorine (27 to 150 mg-min/L at 4 degrees C). Inactivation of M. terrae in wastewater was initially rapid, with 2.5 log reduction at 14 mJ/cm2 and 56 mg-min/L for UV and free chlorine, respectively. However, in effluent and 100-microm filtered wastewater, spiked M. terrae was present to the highest doses evaluated. Interestingly, M. terrae passed through 41- and 20-microm filters were inactivated rapidly, with no survivors after moderate disinfection doses. Inactivation of Mycobacteria in wastewater may be compromised by aggregates larger than 41 microns.