NATO/CCMS Pilot study workshop on air pollution trarfsport and diffusion over coastal urban areas

The NATO/CCMS Pilot Study “Air pollution transport and diffusion over coastal urban areas” held an international workshop in Athens, 3–5 May 1993. The objective of this workshop was to develop guidelines for it reference experiment in a coastal urban area. It was intended that the guidelines would be sufficiently general that they could be applied to any coastal urban area, but Athens was bome in mind as a suitable candidate location. On the first day of the workshop, invited speakers delivered their lectures on different issues of dispersion in urban coastal areas. The second day was devoted to discussions in working groups focusing on key issues, such as, emissions' inventory, meteorological measurements, surface pollutant concentration measurements, aircraft measurements, remote sensing and model evaluation. On the final half-day the rapporteur from each working group reported on its work. Their reports are briefly summarized in the present paper.     

The challenge of integrating non-continuous processes – milk powder plant case study

The integration of non-continuous processes such as a milk powder plant presents a challenge for existing process integration techniques. Current techniques are generally based on steady and continuous operation which for some industries is not the case. Milk production varies considerably during the year as dairy cows in New Zealand are grazed on pasture. In this paper the potential for indirect heat transfer between the several plants using a heat recovery loop and stratified tank at a typical New Zealand dairy factory is investigated. The maximum amount of heat recovery is calculated for a range of recirculation loop temperatures. The maximum amount of heat recovery can be increased considerably if the temperature of the hot fluid in the recirculation loop is varied depending on which condition the site is operating under.     

Results of a technology demonstration project to compare rapid aquatic toxicity screening tests in the analysis of industrial effluents

The results of a 'BioWise' demonstration project to assess the comparative sensitivity and practicality of seven new assays for the direct assessment of ecotoxicity in industrial effluents are presented. In addition the aim of the project was to validate the results of the new assays against benchmark data generated from non-proprietary, rapid, microplate screening assays using the regulatory species; freshwater crustacean Daphnia magna and green algae Selenastrum capricornutum, chosen in view of their environmental relevance. The new commercial test assays were: Daphnia magna, Selenastrum capricornutum and Thamnocephalus platyurus Toxkits supplied by Vickers Laboratories Ltd, containing dormant, immobilised life stages of the test species; GreenScreen EM, a yeast based assay for genotoxicity and general acute toxicity supplied by Gentronix Ltd; and CellSense a mediated, amperometric whole cell biosensor based on immobilised activated sludge and E. coli. 38 effluent samples supplied by members of SOCSA (Specialised Organic Chemicals Sector Association) were examined over a period of 13 months, in the project co-ordinated by the AstraZeneca Brixham Environmental Laboratory, and part funded by BioWise via the UK Government Department of Trade and Industry.     

A yeast-based cytotoxicity and genotoxicity assay for environmental monitoring using novel portable instrumentation

An assay capable of simultaneously measuring both general toxicity and more subtle genotoxicity, in aqueous environmental samples, is described. The assay uses eukaryotic (yeast) cells, genetically modified to express a green fluorescent protein (GFP) whenever DNA damage, as a result of exposure to genotoxic agents, is repaired. A measure of the reduction in cell proliferation is used to characterise general toxicity producing familiar EC(50) and LOEC data. The assay protocol has been developed for proposed use in the field and hence employs dedicated, portable instrumentation, the development of which is described. A range of environmentally relevant substances has been evaluated using the assay, including solutions of metal ions, solvents and pesticides. Preliminary data comparing the yeast assay's response to that of a standard Daphnia test in the analysis of the toxicity of 34 varied industrial waste effluents are also presented. The sensitivity to a wide range of substances and effluents suggests the assay should be useful for environmental toxicity monitoring.     

Clear and present danger? The use of a yeast biosensor to monitor changes in the toxicity of industrial effluents subjected to oxidative colour removal treatments

Discharges of coloured effluents into surface waters provide conspicuous evidence of the impact of industry on the environment. The textile industry is an obvious candidate for sources of such discharges. Conventional treatment methods appear to alleviate this situation by removing colour, however the affect on toxicity is less obvious. The objective of this study was to examine the changes in effluent toxicity during the course of two alternative wastewater treatment methods, ozonation and electrochemical oxidation, using a novel toxicity biosensor, GreenScreen EM. The biosensor is capable of measuring both general acute toxicity (cytotoxicity), and more specifically genotoxicity, that is damage to a cell's DNA structure, replication or distribution, caused by substances that may be mutagenic and/or carcinogenic. The biosensor utilises a modified strain of the brewers yeast Saccharomyces cerevisiae, incorporating a gene encoding green fluorescent protein (GFP) linked to the inducible promoter of the DNA damage responsive RAD54 gene. Upon exposure to a genotoxin, the production of GFP is up-regulated in parallel with RAD54, and the resulting cellular fluorescence provides a measure of genotoxicity. Acute toxicity is simultaneously determined by monitoring relative total growth of the cell culture during incubation. The results presented in this paper show that a reduction in colouration does not necessarily correspond to a reduction in effluent toxicity.