Estimated distributions of personal exposure to respirable particles

A method of estimating distributions of exposure to respirable particles is presented. Using pollutant monitoring data from outdoors and indoors, time-activity data and a time-weighted exposure model, means and variances for exposure distributions are generated. Variances are estimated using Gauss' law of error propagation. The model is calibrated using data from a personal monitoring study. Estimated distributions of exposure to respirable particles for children in six cities living in homes with and without smokers are presented. The implications of these estimates for air pollution epidemiology and needs for further research are discussed.     

Practicing food justice at Dig Deep Farms & Produce,East Bay Area,California: self-determination as a guiding value and intersections with foodie logics

This article describes Dig Deep Farms & Produce, a food justice organisation and urban farm working to stimulate local economic development, create jobs, and improve the quality and accessibility of food in Ashland and Cherryland in California's Bay Area. Their practices are based on self-determined values although they take a flexible, anti-essentialist approach to foodie logics, which are prominent and problematic in the Bay Area. The case study then examines specific practices and strategies, as well as intersections with foodie logics, in three arenas – values determination, strategic partnerships, and foodways – that help to cultivate food justice and highlights key characteristics of food justice work: emphasising self-determination and working to fundamentally change the economic and social conditions of food apartheid.     

Taking Action Against Ocean Acidification: A Review of Management and Policy Options

Ocean acidification has emerged over the last two decades as one of the largest threats to marine organisms and ecosystems. However, most research efforts on ocean acidification have so far neglected management and related policy issues to focus instead on understanding its ecological and biogeochemical implications. This shortfall is addressed here with a systematic, international and critical review of management and policy options. In particular, we investigate the assumption that fighting acidification is mainly, but not only, about reducing CO₂ emissions, and explore the leeway that this emerging problem may open in old environmental issues. We review nine types of management responses, initially grouped under four categories: preventing ocean acidification; strengthening ecosystem resilience; adapting human activities; and repairing damages. Connecting and comparing options leads to classifying them, in a qualitative way, according to their potential and feasibility. While reducing CO₂ emissions is confirmed as the key action that must be taken against acidification, some of the other options appear to have the potential to buy time, e.g. by relieving the pressure of other stressors, and help marine life face unavoidable acidification. Although the existing legal basis to take action shows few gaps, policy challenges are significant: tackling them will mean succeeding in various areas of environmental management where we failed to a large extent so far.     

The Triple Bottom Line for Sustainable Community Development

Rural communities in Australia are confronting a period of unprecedented change. They face declining commodity prices, the withdrawal of both public and private sector services, such as banks and hospitals, and the closure of small businesses. Their populations are in decline, with young people leaving for the larger regional centres. Many also face a declining resource base as soils become saline and water resources are sold to areas with higher unit returns. This paper presents a framework for sustainable community development based on emerging ideas of performance auditing and the development of progress indicators. The triple bottom line community audit approach is recast for the community level, measuring performance on improved community wellbeing, reduced environmental impact and increased economic vitality. Rural communities need to redefine their future. A sustainability focus offers a way forward. Las comunidades rurales en Australia estan afrontando un periodo de cambio sin precedente. Enfrentan disminución en los precios de los productos, retiro de servicios de ambos sectores, publico y privado, como bancos y hospitales y el cierre de pequeños negocios. Su población está disminuyendo, la gente joven emigra hacia centros regionales mas grandes. Muchos tambien enfrentan un deterioro en los recursos base ya que los suelos se tornan salinos, y los recursos de agua son vendidos a áreas con retorno de unidad mas alto. Este documento presenta una estructura para el desarrollo comunitario sostenible basado en el surgimiento de ideas de la revisión del desempeño y del desarrollo de indicadores de progreso. El enfoque de auditoria del triple resultado final esta rehecho para el nivel de la comunidad, midiendo el desempeño en el bienestar de la comunidad mejorada, el impacto ambiental reducido, y la vitalidad económica incrementada. Las comunidades rurales necesitan redefinir su futuro. Un enfoque sostenible ofrece una vía hacia adelante.     

Mixed models for assessing correlation in the presence of replication

The need to assess correlation in settings where multiple measurements are available on each of the variables of interest often arises in environmental science. However, this topic is not covered in introductory statistics texts. Although several ad hoc approaches can be used, they can easily lead to invalid conclusions and to a difficult choice of an appropriate measure of the correlation. Lam et al. approached this problem by using maximum likelihood estimation in cases where the replicate measurements are linked over time, but the method requires specialized software. We reanalyze the data of Lam et al. using PROC MIXED in SAS and show how to obtain the parameter estimates of interest with just a few lines of code. We then extend Lam et al.'s method to settings where the replicate measurements are not linked. Analysis of the unlinked case is illustrated with data from a study designed to assess correlations between indoor and outdoor measurements of benzene concentration in the air.     

Trace element chemistry in residual-treated soil: key concepts and metal bioavailability

Trace element solubility and availability in land-applied residuals is governed by fundamental chemical reactions between metal constituents, soil, and residual components. Iron, aluminum, and manganese oxides; organic matter; and phosphates, carbonates, and sulfides are important sinks for trace elements in soil-residual systems. The pH of the soil-residual system is often the most important chemical property governing trace element sorption, precipitation, solubility, and availability. Trace element phytoavailability in residual-treated soils is often estimated using soil extraction methods. However, spectroscopic studies show that sequential extraction methods may not be accurate in perturbed soil-residual systems. Plant bioassay is the best method to measure the effect of residuals on phytoavailability. Key concepts used to describe phytoavailability are (i) the salt effect, (ii) the plateau effect, and (iii) the soil-plant barrier. Metal availability in soil from metal-salt addition is greater than availability in soil from addition of metal-containing residuals. Plant metal content displays plateaus at high residual loadings corresponding to the residual's metal concentration and sorption capacity. The soil-plant barrier limits transmission of many trace elements through the food chain, although Cd (an important human health concern) can bypass the soil-plant barrier. Results from many studies that support these key concepts provide a basis of our understanding of the relationship between trace element chemistry and phytoavailability in residual-treated soils. Research is needed to (i) determine mechanisms for trace element retention of soil-residual systems, (ii) determine the effect of residuals on ecological receptors and the ability of residuals to reduce ecotoxicity in metal-contaminated soil, and (iii) predict the long-term bioavailability of trace elements in soil-residual systems.