Adaptation to air pollution

This study examines human adaptation to air pollution by comparing responses to photochemical smog of long-term residents and recent residents of the Los Angeles air basin. Long-term residents in comparison to recent migrants use a higher response criterion to identify smog in a visual signal detection task. There is no difference in visual sensitivity between the two residential groups in detecting the presence of air pollution in photographic slides. Thus for low levels of visual air pollution, both long-term residents of Los Angeles and new migrants are equally accurate in detecting the presence of smog. Long-term residents, however, are less likely to decide that smog is present in a scene. This response bias is interpreted in terms of adaptation level theory. Characteristics of the response bias differences between the two residential groups are examined in detail using signal detection procedures.     

A rapid and accurate method for the determination of plutonium in food using magnetic sector ICP-MS with an ultra-sonic nebuliser and ion chromatography

In the event of a nuclear incident it is essential that analytical information on the distribution and level of contamination is available. An ICP-MS method is described which can provide data on plutonium contamination in food within 3 h of sample receipt without compromising detection limits or accuracy relative to traditional counting methods. The method can also provide simultaneous determinations of americium and neptunium. Samples were prepared by HNO3 closed-vessel microwave digestion, evaporated to dryness and diluted into a mobile phase comprising 1.5 M HNO3 and 0.1 mM 2,6-pyridinedicarboxylic acid. A commercially available polystyrene-divinylbenzene ion chromatography column provides on-line separation of 239Pu and 238U reducing the impact of the 238U1H interference. Oxidation of the sample using H2O2 ensures all Pu is in the Pu(+4) state. The oxidation also displaces Np away from the solvent front by changing the oxidation state from Np(+3) to Np(+4) and produces the insoluble Am(+4) ion. Simultaneous Pu, Am and Np analyses therefore require omission of the oxidation stage and some loss of Pu data quality. Analyses were performed using a magnetic sector ICP-MS (Finnigan MAT Element). The sample is introduced to the plasma via an ultrasonic nebuliser-desolvation unit (Cetac USN 6000AT+). This combination achieves an instrumental sensitivity of 238U > 2 x 10(7) cps/ppb and removes hydrogen from the sample gas, which also inhibits the formation of 238U1H. The net effect of the improved sample introduction conditions is to achieve detection levels for Pu of 0.020 pg g(-1) (4.6 x 10(-2) Bq kg(-1)) which is significantly below 1/10th of the most stringent EU (European Union) legislation, currently 0.436 pg g(-1) (1 Bq kg(-1)) set for baby food. The new method was evaluated with a range of biological samples ranging from cabbage to milk and meat. Recovery of Pu agrees with published values (100% +/- 20%).     

On the propagation of error in air pollution measurements

Four methods for estimating the uncertainties in air pollution measurements are outlined. The approaches are: analytical solution-approximation; application of distribution theory; experimentation; and simulation. The advantages and disadvantages of each method are illustrated using data from High-Volume air samplers, the instrument most commonly used for monitoring ambient concentrations of airborne particles.Dr Evans is Assistant Professor of Environmental Science and Mr Kinney is a doctoral candidate in the Department of Environmental Science and Physiology, Harvard School of Public Health. Dr Cooper is at the Manufacturing Research Laboratory, Thomas J. Watson Research Center, IBM, Yorktown Heights, NY.     

Evaluation of Lead Availability in Amended Soils Monitored Over a Long-Term Time Period

Two different soil amendment processes were evaluated for reducing lead availability from a contaminated soil at a demonstration study site, to reduce potential public health and environmental concerns. A limited variety of in vitro laboratory “availability” tests (relative bioaccessible and environmental mobility) were performed to determine if the available lead in the contaminated soil would be less available after in situ soil amendment (chemical treatment). The relative bioaccessibility results were evaluated in both a short-term period (within 24 h after treatment) and over a long-term time period (quarterly basis for 5 years). Reduction in relative bioaccessibility was noted for one of the treatments immediately after treatment; however, both treatments indicated a significant upward trend in bioaccessibility values over a 5-year time period after treatment. The comparison between the treated units and the control units indicated that the long-term effectiveness of the treatment processes could not be demonstrated.     

Governing local sustainability

This paper draws upon the DISCUS (Developing Institutional and Social Capacity for Sustainable Development) research project, co-funded by the European Commission. The project was undertaken during 2001 – 2004 and involved an in-depth study of 40 European towns and cities in order to understand the institutional and social factors and conditions that might contribute to policy ‘achievement' or ‘failure' in local sustainable development policy and practice. Based on the findings of this research it proposes a conceptual framework for local sustainable development, linking the concepts of institutional capital, social capital and governance to provide a model for understanding the governing of local sustainability. The research shows that in those cases that exhibit sustainable development policy achievements, there are also greater levels of civil society activity and knowledge regarding sustainability issues, and high levels of institutional capacity. Confident local government is crucial to the development of institutional capacity and to institutional learning. One aspect of this is local authorities being equipped to address the longer-term issues and to have a strategic vision for a sustainable future.     

ESTIMATING NUTRIENT AND SEDIMENT THRESHOLD CRITERIA FOR BIOLOGICAL IMPAIRMENT IN PENNSYLVANIA WATERSHEDS1

ABSTRACT: This study employs a simple nonlinear statistical approach to establish nitrogen, phosphorus, and sediment concentration and unit area load thresholds to aid in the evaluation of aquatic biological health of watersheds within the state of Pennsylvania. Flow, nitrogen and phosphorus species, sediment, basin area, land cover, and biological assessment data were assembled for 29 Pennsylvania watersheds. For each watershed, rating curves depicting flow versus load relationships were developed using the U.S. Environmental Protection Agency's (USEPA's) storage and retrieval database (STORET) flow and concentration data, then applied to daily flow data obtained from U.S. Geological Survey (USGS) daily flow gauging stations to estimate daily load between 1989 and 1999. The load estimates and concentration data were then sorted into six sets of data: mean annual unit area nitrogen, phosphorus, and sediment loads; and average nitrogen, phosphorus, and sediment concentrations. Results of Mann‐Whitney tests conducted on each of the six datasets indicate that there is a statistically significant difference between the concentrations and unit area loads of nitrogen, phosphorus, and sediment in impaired and unimpaired watersheds. Concentration thresholds, calculated as the midpoint between the impaired and unimpaired watersheds’ 95 percent confidence interval for the median, were estimated to be 2.01 mg/L, 0.07 mg/L, and 197.27 mg/L for nitrogen, phosphorus, and sediment, respectively. Annual unit area load thresholds were estimated to be equal to 8.64 kg/ha, 0.30 kg/ha, and 785.29 kg/ha, respectively, for nitrogen, phosphorus, and sediment species.