New indicator approaches for effective urban air quality management.

Measurements of urban air quality at monitoring stations in developed countries have frequently involved the criteria gaseous pollutants, particulates, hazardous air pollutants, perceived air quality and relevant meteorological conditions. Large numbers of indicators have therefore been established to quantify emissions, concentrations and environmental and human health impacts of each of these groups of substances. To simplify the data for management, several indicators have been grouped together to form urban air quality indices but the weightings of individual variables is contentious. In industrialising and developing countries, data may be limited and traditional air pollutant indicators cannot often be constructed. The emphasis therefore has to be placed on the development of policy-relevant indicators, such as Response Indicators that reflect different policy principles for regulating air pollutant emissions. Indices that quantify the air quality management capabilities and capacities at the city level provide further useful decision-relevant tools. Four sets of indices, namely, 1. air quality measurement capacity, 2. data assessment and availability, 3. emissions estimates, and 4. management enabling capabilities, and a composite index to evaluate air quality management capability, were constructed and applied to 80 cities. The indices revealed that management capability varied widely between the cities. In some of the cities, existing national knowledge on urban air quality could have been more effectively used for management. It was concluded that for effective urban air quality management, a greater emphasis should be given, not just to monitoring and data capture programmes, but to the development of indicators and indices that empower decision-makers to initiate management response strategies. Over-reliance on restricted, predetermined sets of traditional air quality indicators should be avoided.

Assessment of exposure to chemical contaminants in water and food.

UNLABELLED: The main questions on the validity of the studies and routine monitoring (e.g., in the scope of the WHO/UNEP GEMS programme) assessing exposure to chemicals through water and food (i.e., through digestion) relate to the following. (a) SAMPLING: variations due to sampling strategy and approach usually exceed analytical errors. (b) MEASUREMENT: quality assessment and quality control (QA/QC) procedures are essential. However, potential limitations of measurement errors resulting from implementation of these procedures should be kept in perspective with other errors and confounding factors. (c) METHODOLOGY: which depends on the variability of the intake patterns in the population, as well on the adequacy of the information on the consumption of food of a specified type as an indicator of the intake of a specific chemical. These factors should be considered in particular in studies using 'food basket' methods. Whenever possible, structure of the population in respect to the factors determining typical diet should be registered. (d) Form of reporting: limiting possibilities for re-analysis of the exposure estimates. In conclusion, the routinely collected data on exposure through food and water should be used with care in epidemiological studies. Assessment of the exposure conducted specially for the epidemiological study should consider possible changes of the diet with time. The data on confounders are crucial for exposure estimates.

The role of biomarkers in environmental assessment (4). Terrestrial plants.

The potential of metabolites, enzymatic processes and changes in plant performance as biomarkers in environmental assessment is reviewed. Biomarkers may be used as an early warning system of specific or general stress at each biological level, from molecules to ecosystems. The sensitivity of a species and, thus, the efficiency of a biomarker will depend on the degree of already present adaptation to environmental stress and on the homogeneity of the investigated population. Biomarkers for specific environmental stresses are scarce; better known are biomarkers for environmental stress complexes such as heavy metals, physiological drought and extreme temperature or biomarkers as a reaction on a full scale of environmental stresses. It is argued that a battery of biomarkers is necessary to evaluate chemical hazards to species.

Infections and infection control among residents of eight rural Wisconsin nursing homes.

During 1984 and 1985, an initial prevalence survey and six consecutive months of comprehensive prospective surveillance were conducted in eight rural Wisconsin nonproprietary nursing homes managed by eight nonprofit hospitals in the same communities. Our purpose was to define the infections in the residents and the infection control programs in the nursing homes. The initial prevalence survey analyzed the records of all 403 residents of the eight nursing homes. The average resident was 83.4 years old and had 3.4 chronic diseases noted on the chart. During this initial survey, 52 (12.9%) of the residents were found to have 56 active infections of all types. During six consecutive months of comprehensive surveillance in the eight nursing homes, 265 episodes of acute infection were found for an overall incidence of 10.7 infections per 100 resident months. Clusters of infection by site, pathogen, or month of onset were quite uncommon throughout the study. Susceptibility testing of organisms recovered from infections failed to reveal any clinically important resistance patterns. Because nursing homes are different in many respects from hospitals, appropriately modified definitions and infection control strategies are required for nursing homes and their residents.

Nosocomial infections in 15 rural Wisconsin hospitals--results and conclusions from 6 months of comprehensive surveillance.

Fifteen rural Wisconsin acute care community hospitals with an average approved bed size of 55 and an average daily census of 28 patients participated in a nosocomial infection control project. Each hospital Infection Control Practitioner (ICP) was trained and conducted prospective nosocomial infection surveillance on all patients admitted to the hospital for 6 consecutive months between May 1, 1984 and April 30, 1985. Two hundred twenty nosocomial infections were reported among 13,420 discharged patients for an incidence rate of 1.64 infections per 100 discharged patients. One hundred sixty-four patients had one nosocomial infection. Twenty-three patients had two or more. Infection rates were highest among gynecology--4.9% and general surgery patients--4.0%, and lowest among newborns--0.3% and pediatric patients--0%. 39.7% of the infections were of the urinary tract, 27.9% of surgical wounds, 16% pneumonia, and 1.4% primary bacteremia. The other infections were in seven additional sites. Risk factors associated with acquisition of infections included old age, urinary catheterization, and/or a surgical procedure. The overall nosocomial surgical wound infection incidence for inpatient procedures was 1.9%, with incidences of 0.4% for hernia repair, 1.3% for cholecystectomy, 3.3% for appendectomy, 4.0% for total abdominal hysterectomy, and 3.9% for cesarean sections. The incidence of nosocomial infections was 2.7 infections per 100 discharged patients age 65 years or over and 0.9 infections per 100 discharged patients less than 65 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Hallucinations of widowhood.

Widowed residents of two nursing homes who were oriented to person, time, and place were interviewed to determine the extent to which they had hallucinatory experiences of their deceased spouse. Fifty-two interviews were completed with 46 widows and six widowers. Results are reported for the widows. Twenty-eight (61%) of the widows reported hallucinatory experiences of their deceased spouse. Twenty-four (86%) of the widows described the experiences as good or helpful. Thirteen (46%) reported that the experiences continue to happen. Nineteen (54%) of the widows had never discussed the experiences with anyone before this study. These results are surprisingly similar to previously published findings by Rees in Wales and suggest that these experiences are more common in the United States than has been recognized.

The accumulation and assimilation of dimethylselenide by four plant species.

Plants of Agrostis tenuis Sibth., Hordeum vulgare L., Lycopersicon esculentum Mill. and Raphanus sativus L. were grown hydroponically in sealed systems and fumigated with 8 µg m(-3) [(75)Se]-dimethylselenide. The accumulation of (75)Se was measured and the shoot tissues were extracted to examine the products of the (75)Se assimilation. Characteristic differences were observed between species in the accumulation of (75)Se and the transport from shoots to roots. High-voltage electrophoresis and chromatography of extracts made with 80% aqueous ethanol revealed the presence of inorganic selenite as an assimilation product as well as the selenium analogues of glutathione and methionine. Extensive incorporation of (75)Se into protein-bound selenomethionine was observed in all plant species.

Geochemistry and ecology.

This paper discusses the importance of geochemistry as a determining factor in the evolutionary development of plant assemblages. Three contrasting examples of geochemical systems are described and considered in relation to their effects on plant growth and development. Soils derived from serpentines may contain elevated and sometimes toxic concentrations of Cr and Ni depending on mineral composition and weathering processes. These conditions have so modified plant growth during the past few million years that specialized floras have evolved on particular sites. Extensive areas throughout the world contain high concentrations of Se but these have not always been accompanied by the development of specific floras. Geochemistry can help explain how Se-specific floras have developed in several Western States of America but are absent on Se-rich sites in the Republic of Ireland. Pronounced effects of As toxicity in plants have been recognized in recent years especially from areas polluted by smelter waste and fallout. As-tolerant genotypes have developed during the past 100 years and may still be evolving at the present time.

Chromium uptake and transport in barley seedlings (Hordeum vulgare L.).

Potassium chromate is more toxic to the growth of barley in solution culture than chromic chloride, though apparent uptake of the latter is much faster. Inhibitor studies indicate that CrO4 (2-) uptake is "active" whereas Cr(3+) uptake is passive, demonstrating that the two forms do not share a common uptake mechanism. Studies on the form of Cr inside root cells show that in plants fed CrO4 (2-) the Cr remains largely unchanged whereas in plants fed Cr(3+) a little CrO4 (2-) (0.5 per cent) is produced. This conversion is dependent on the presence of living material and is probably enzymatic. Chromate uptake follows Michaelis-Menten kinetics at low concentration and is competitively inhibited by sulphate. Transport of chromium up the root is very slow, accounting for the low levels of Cr in the shoots. Chromate is transported better than Cr(3+) though still to a very limited extent. These experiments provide a physiological basis for previous observations.