Modelling of occupational respirable crystalline silica exposure for quantitative exposure assessment in community-based case-control studies

We describe an empirical model for exposure to respirable crystalline silica (RCS) to create a quantitative job-exposure matrix (JEM) for community-based studies. Personal measurements of exposure to RCS from Europe and Canada were obtained for exposure modelling. A mixed-effects model was elaborated, with region/country and job titles as random effect terms. The fixed effect terms included year of measurement, measurement strategy (representative or worst-case), sampling duration (minutes) and a priori exposure intensity rating for each job from an independently developed JEM (none, low, high). 23,640 personal RCS exposure measurements, covering a time period from 1976 to 2009, were available for modelling. The model indicated an overall downward time trend in RCS exposure levels of -6% per year. Exposure levels were higher in the UK and Canada, and lower in Northern Europe and Germany. Worst-case sampling was associated with higher reported exposure levels and an increase in sampling duration was associated with lower reported exposure levels. Highest predicted RCS exposure levels in the reference year (1998) were for chimney bricklayers (geometric mean 0.11 mg m(-3)), monument carvers and other stone cutters and carvers (0.10 mg m(-3)). The resulting model enables us to predict time-, job-, and region/country-specific exposure levels of RCS. These predictions will be used in the SYNERGY study, an ongoing pooled multinational community-based case-control study on lung cancer.     

How well does XAD resin extraction recover halogenated disinfection byproducts for comprehensive identification and toxicity testing?

Halogenated disinfection byproducts (DBPs) are an unintended consequence of drinking water disinfection, and can have significant toxicity. XAD resins are commonly used to extract and enrich trace levels of DBPs for comprehensive, nontarget identification of DBPs and also for in vitro toxicity studies. However, XAD resin recoveries for complete classes of halogenated DBPs have not been evaluated, particularly for low, environmentally relevant levels (ng/L to low µg/L). Thus, it is not known whether levels of DBPs or the toxicity of drinking water might be underestimated. In this study, DAX-8/XAD-2 layered resins were evaluated, considering both adsorption and elution from the resins, for extracting 66 DBPs from water. Results demonstrate that among the 7 classes of DBPs investigated, trihalomethanes (THMs), including iodo-THMs, were the most efficiently adsorbed, with recovery of most THMs ranging from 50%-96%, followed by halonitromethanes (40%-90%). The adsorption ability of XAD resins for haloacetonitriles, haloacetamides, and haloacetaldehydes was highly dependent on the individual species. The adsorption capacity of XAD resins for haloacetic acids was lower (5%-48%), even after adjusting to pH 1 before extraction. Recovery efficiency for most DBPs was comparable with their adsorption, as most were eluted effectively from XAD resins by ethyl acetate. DBP polarity and molecular weight were the two most important factors that determine their recovery. Recovery of trichloromethane, iodoacetic acid, chloro- and iodo-acetonitrile, and chloroacetamide were among the lowest, which could lead to underestimation of toxicity, particularly for iodoacetic acid and iodo-acetonitrile, which are highly toxic.     

Self-Reported Seat Belt Use in Four Countries: A Telephone Survey

A telephone survey was conducted in four countries in November 1998 to compare drivers in the United States with those in Australia, Canada, and the United Kingdom regarding their attitudes toward seat belts and belt use laws. More than 90 percent of the 2251 respondents said they thought seat belts are effective, but self-reported belt use was significantly lower in the United States than in the other countries. Respondents in Australia and the United Kingdom had similar views about what they thought were important reasons for using seat belts and had the highest self-reported use. Reasons given for using belts by Canadian and US respondents were quite similar to one another, yet US respondents had significantly lower self-reported use rates, a difference thought to be due to vigorous enforcement of the law in Canada. US drivers were less likely than Australian and UK drivers to say they used belts out of habit, to avoid a ticket, or because it is required by law and more likely to say they used belts for situational reasons. US drivers were least likely to be in favor of belt use laws. Canadian drivers reported the most experience being checked by police for belt use and were most likely to think that nonusers would be caught. US drivers in primary enforcement jurisdictions were more likely than those in secondary jurisdictions to think that drivers not using belts would be caught and more likely to say they always used belts. Results of this survey indicate that seat belt use in the United States could be increased by adoption of primary enforcement laws and highly visible enforcement programs of the type used in Canada, and that seat belt use could be increased in all countries by increasing the penalties for nonuse.     

Physical basis of coastal adaptation on tropical small islands

Small tropical islands are widely recognized as having high exposure and vulnerability to climate change and other natural hazards. Ocean warming and acidification, changing storm patterns and intensity, and accelerated sea-level rise pose challenges that compound the intrinsic vulnerability of small, remote, island communities. Sustainable development requires robust guidance on the risks associated with natural hazards and climate change, including the potential for island coasts and reefs to keep pace with rising sea levels. Here we review these issues with special attention to their implications for climate-change vulnerability, adaptation, and disaster risk reduction in various island settings. We present new projections for 2010–2100 local sea-level rise (SLR) at 18 island sites, incorporating crustal motion and gravitational fingerprinting, for a range of Intergovernmental Panel on Climate Change global projections and a semi-empirical model. Projected 90-year SLR for the upper limit A1FI scenario with enhanced glacier drawdown ranges from 0.56 to 1.01 m for islands with a measured range of vertical motion from ?0.29 to +0.10 m. We classify tropical small islands into four broad groups comprising continental fragments, volcanic islands, near-atolls and atolls, and high carbonate islands including raised atolls. Because exposure to coastal forcing and hazards varies with island form, this provides a framework for consideration of vulnerability and adaptation strategies. Nevertheless, appropriate measures to adjust for climate change and to mitigate disaster risk depend on a place-based understanding of island landscapes and of processes operating in the coastal biophysical system of individual islands.     

In vitro conservation and sustained production of breadfruit (Artocarpus altilis, Moraceae): modern technologies for a traditional tropical crop

Breadfruit (Artocarpus altilis, Moraceae) is a traditionally cultivated, high-energy, high-yield crop, but widespread use of the plant for food is limited by poor quality and poor storage properties of the fruit. A unique field genebank of breadfruit species and cultivars exists at the National Tropical Botanical Garden in the Hawaiian Islands and is an important global resource for conservation and sustainable use of breadfruit. However, this plant collection could be damaged by a random natural disaster such as a hurricane. We have developed a highly efficient in vitro plant propagation system to maintain, conserve, mass propagate, and distribute elite varieties of this important tree species. Mature axillary shoot buds were collected from three different cultivars of breadfruit and proliferated using a cytokinin-supplemented medium. The multiple shoots were maintained as stock cultures and repeatedly used to develop whole plants after root differentiation on a basal or an auxin-containing medium. The plantlets were successfully grown under greenhouse conditions and were reused to initiate additional shoot cultures for sustained production of plants. Flow cytometry was used to determine the nuclear deoxyribonucleic acid content and the ploidy status of the in vitro grown population. The efficacy of the micropropagation protocols developed in this study represents a significant advancement in the conservation and sustained mass propagation of breadfruit germplasm in a controlled environment free from contamination.     

Lessons from an Evaluation of a Boater Outreach Program for Manatee Protection

Watercraft collisions account for 25–30% of manatee deaths annually in Florida. Education and outreach interventions for boaters are strategies for reducing manatee mortality. We evaluated the effectiveness of the Manatee Watch program by surveying primary boat users whose boats were approached by Manatee Watch. We compared the attitudes, knowledge, and behavioral intentions of boaters who received Manatee Watch materials with a control group of boaters observed by the Florida Marine Research Institute in Tampa Bay during 1999–2001. Results of the 51-item telephone survey with 499 boaters indicated that the Manatee Watch intervention had little effect on boater’s attitudes, knowledge, and behaviors regarding manatees. However, individual attitude scores were positively correlated with safe boating behaviors in shallow waters including maintaining a slower speed and watching out for manatees. Overall knowledge about manatees was correlated with one manatee-safe boating behavior. To improve efficacy, educators should (a) incorporate evaluation into the planning stages of program development; (b) target messages to influence boaters’ attitudes toward manatees and ecosystem health, and their feelings of ownership and empowerment; (c) facilitate active participation of the boaters; and (d) increase the duration and variety of intervention.     

Characteristics of Composition B particles from blow-in-place detonations

We sampled residues from high-order and low-order blow-in-place detonations of mortars and projectiles filled with Composition B (Comp B), a TNT and RDX mixture. Our goals were to (1) characterize the types of explosive particles, (2) estimate the explosive 'footprint' for different munitions, and (3) estimate the mass of Comp B remaining after each detonation. The aerial deposition of Comp B particles helps estimate how large of an area is contaminated by a low-order detonation and how best to sample residue resulting from different rounds. We found that the high-order detonations deposited microgram to milligram quantities whereas the low-order detonations deposited gram quantities of Comp B. For the high-order detonations the concentration of Comp B in the residue decreased as a function of distance from the blast. The low-order tests scattered centimeter-sized chunks and millimeter-sized or smaller particles of Comp B. The chunks were randomly scattered whereas the number of millimeter-sized particles decreased with distance from the detonation. For both high- and low-order detonations we found that the smaller munitions deposited less Comp B than the larger munitions and deposited it closer to the detonation point.     

Organohalogen chemicals in human blood from the United Kingdom

Blood serum from 154 volunteers at 13 UK locations in 2003 were analysed for a range of PCBs, organochlorine pesticides and PBDEs. HCB, p,p'-DDE and p,p'-DDT and beta-HCH were the dominant organochlorine pesticides in most samples. BDEs 47, 99, 100, 153, 154 and 183 were the most regularly detected PBDEs. This study is the first report of BDE209 in UK human blood (found in 11 samples, range < 15-240 ng/g lipid). Concentration and age correlated for the less easily metabolised PCBs, p,p'-DDT and p,p'-DDE, HCB and HCHs. With increasing age females tended to have lower concentrations of the more chlorinated PCBs than males. Similar PBDE concentrations, and distributions, to those reported in the general population in Sweden in 2002 were found, despite differences in historical PBDE production and usage. There is increasing regulation to control persistent and bioaccumulative chemicals, and establishing human exposure will help to identify substances which should be urgently phased out.     

Defining Indicators and Standards for Tourism Impacts in Protected Areas: Cape Range National Park,Australia

Visitors’ perceptions of impacts and acceptable standards for environmental conditions can provide essential information for the sustainable management of tourist destinations, especially protected areas. To this end, visitor surveys were administered during the peak visitor season in Cape Range National Park, on the northwest coast of Western Australia and adjacent to the iconic Ningaloo Reef. The central focus was visitors’ perceptions regarding environmental conditions and standards for potential indicators. Conditions considered of greatest importance in determining visitors’ quality of experience included litter, inadequate disposal of human waste, presence of wildlife, levels of noise, and access to beach and ocean. Standards were determined, based on visitors’ perceptions, for a range of site-specific and non-site-specific indicators, with standards for facilities (e.g., acceptable number of parking bays, signs) and for negative environmental impacts (e.g., levels of littering, erosion) sought. The proposed standards varied significantly between sites for the facilities indicators; however, there was no significant difference between sites for environmental impacts. For the facilities, the standards proposed by visitors were closely related to the existing situation, suggesting that they were satisfied with the status quo. These results are considered in the context of current research interest in the efficacy of visitor-derived standards as a basis for protected area management.     

Rain forest fragmentation and the proliferation of successional trees

The effects of habitat fragmentation on diverse tropical tree communities are poorly understood. Over a 20-year period we monitored the density of 52 tree species in nine predominantly successional genera (Annona, Bellucia, Cecropia, Croton, Goupia, Jacaranda, Miconia, Pourouma, Vismia) in fragmented and continuous Amazonian forests. We also evaluated the relative importance of soil, topographic, forest dynamic, and landscape variables in explaining the abundance and species composition of successional trees. Data were collected within 66 permanent 1-ha plots within a large (approximately 1000 km2) experimental landscape, with forest fragments ranging from 1 to 100 ha in area. Prior to forest fragmentation, successional trees were uncommon, typically comprising 2-3% of all trees (> or =10 cm diameter at breast height [1.3 m above the ground surface]) in each plot. Following fragmentation, the density and basal area of successional trees increased rapidly. By 13-17 years after fragmentation, successional trees had tripled in abundance in fragment and edge plots and constituted more than a quarter of all trees in some plots. Fragment age had strong, positive effects on the density and basal area of successional trees, with no indication of a plateau in these variables, suggesting that successional species could become even more abundant in fragments over time. Nonetheless, the 52 species differed greatly in their responses to fragmentation and forest edges. Some disturbance-favoring pioneers (e.g., Cecropia sciadophylla, Vismia guianensis, V. amazonica, V. bemerguii, Miconia cf. crassinervia) increased by >1000% in density on edge plots, whereas over a third (19 of 52) of all species remained constant or declined in numbers. Species responses to fragmentation were effectively predicted by their median growth rate in nearby intact forest, suggesting that faster-growing species have a strong advantage in forest fragments. An ordination analysis revealed three main gradients in successional-species composition across our study area. Species gradients were most strongly influenced by the standlevel rate of tree mortality on each plot and by the number of nearby forest edges. Species-composition also varied significantly among different cattle ranches, which differed in their surrounding matrices and disturbance histories. These same variables were also the best predictors of total successional-tree abundance and species richness. Successional-tree assemblages in fragment interior plots (>150 m from edge), which are subjected to fragment area effects but not edge effects, did not differ significantly from those in intact forest, indicating that area effects per se had little influence on successional trees. Soils and topography also had little discernable effect on these species. Collectively, our results indicate that successional-tree species proliferate rapidly in fragmented Amazonian forests, largely as a result of chronically elevated tree mortality near forest edges and possibly an increased seed rain from successional plants growing in nearby degraded habitats. The proliferation of fast-growing successional trees and correlated decline of old-growth trees will have important effects on species composition, forest dynamics, carbon storage, and nutrient cycling in fragmented forests.