Inhalation dose assessment of indoor radon progeny using biokinetic and dosimetric modeling and its application to Jordanian population

High indoor radon concentrations in Jordan result in internal exposures of the residents due to the inhalation of radon and its short-lived progeny. It is therefore important to quantify the annual effective dose and further the radiation risk to the radon exposure. This study describes the methodology and the biokinetic and dosimetric models used for calculation of the inhalation doses exposed to radon progeny. The regional depositions of aerosol particles in the human respiratory tract were firstly calculated. For the attached progeny, the activity median aerodynamic diameters of 50 nm, 230 nm and 2500 nm were chosen to represent the nucleation, accumulation and coarse modes of the aerosol particles, respectively. For the unattached progeny, the activity median thermodynamic diameter of 1 nm was chosen to represent the free progeny nuclide in the room air. The biokinetic models developed by the International Commission on Radiological Protection (ICRP) were used to calculate the nuclear transformations of radon progeny in the human body, and then the dosimetric model was applied to estimate the organ equivalent doses and the effective doses with the specific effective energies derived from the mathematical anthropomorphic phantoms. The dose conversion coefficient estimated in this study was 15 mSv WLM⁻¹ which was in the range of the values of 6-20 mSv WLM⁻¹ reported by other investigators. Implementing the average indoor radon concentration in Jordan, the annual effective doses were calculated to be 4.1 mSv y⁻¹ and 0.08 mSv y⁻¹ due to the inhalation of radon progeny and radon gas, respectively. The total annual effective dose estimated for Jordanian population was 4.2 mSv y⁻¹. This high annual effective dose calculated by the dosimetric approach using ICRP biokinetic and dosimetric models resulted in an increase of a factor of two in comparison to the value by epidemiological study. This phenomenon was presented by the ICRP in its new published statement on radon.     

Fukushima fallout in Northwest German environmental media

Traces of short- and long-lived fallout isotopes (¹³¹I, ¹³⁴Cs and ¹³⁷Cs) were found in environmental samples collected in Northwest Germany (rain water, river sediment, soil, grass and cow milk) from March to May 2011, following the radioactivity releases after the nuclear accident in Fukushima, Japan. The measured concentrations are consistent with reported concentrations in air, amount of rainfall and expected values applying simple radioecological models. The [¹³⁴Cs]/[¹³⁷Cs] ratio reported for air (about 1) allows for discrimination between “recent” and “old” ¹³⁷Cs. Expected ¹³⁶Cs values fell below the detection limits of the instrumentation, despite large sample masses and long counting times.     

A Contemporary,Sex‐Limited Change in Body Size of an Estuarine Turtle in Response to Commercial Fishing

Abstract: Juvenile growth rate and adult body size are important components of life‐history strategies because of their direct impact on fitness. The diamondback terrapin (Malaclemys terrapin) is a sexually dimorphic, long‐lived turtle inhabiting brackish waters throughout the Atlantic and Gulf coasts of the United States. In parts of its range, terrapins face anthropogenically imposed mortality: juveniles of both sexes inadvertently enter commercial crab traps and drown. For adult females, the carapace eventually grows large enough that they cannot enter traps, whereas males almost never reach that critical size. We compared age structure, carapace dimensions, growth curves, and indices of sexual dimorphism for a Chesapeake Bay population of terrapins (where mortality of turtles is high due to crab traps) with contemporary terrapins from Long Island Sound and museum specimens from Chesapeake Bay (neither group subject to commercial crab traps). We also calculated the allochronic and synchronic rates of evolutionary change (haldanes) for males and females to measure the rate of trait change in a population or between populations, respectively. We found a dramatic shift to a younger male age structure, a decrease in the length of time to terminal female carapace size, a 15% increase in female carapace width, and an increase in sexual dimorphism in Chesapeake Bay. In a new twist, our results implicate a fishery in the selective increase in size of a reptilian bycatch species. These sex‐specific changes in life history and demography have implications for population viability that need to be considered when addressing conservation of this threatened turtle.     

Methanotrophs and methanotrophic activity in engineered landfill biocovers

The dynamics and changes in the potential activity and community structure of methanotrophs in landfill covers, as a function of time and depth were investigated. A passive methane oxidation biocover (PMOB-1) was constructed in St-Nicéphore MSW Landfill (Quebec, Canada). The most probable number (MPN) method was used for methanotroph counts, methanotrophic diversity was assessed using denaturing gradient gel electrophoresis (DGGE) fingerprinting of the pmoA gene and the potential CH₄ oxidation rate was determined using soil microcosms. Results of the PMOB-1 were compared with those obtained for the existing landfill cover (silty clay) or a reference soil (RS). During the monitoring period, changes in the number of methanotrophic bacteria in the PMOB-1 exhibited different developmental phases and significant variations with depth. In comparison, no observable changes over time occurred in the number of methanotrophs in the RS. The maximum counts measured in the uppermost layer was 1.5 × 10⁹ cells g dw^?1 for the PMOB-1 and 1.6 × 10⁸ cells g dw^?1 for the RS. No distinct difference was observed in the methanotroph diversity in the PMOB-1 or RS. As expected, the potential methane oxidation rate was higher in the PMOB-1 than in the RS. The maximum potential rates were 441.1 and 76.0 μg CH₄ h^?1g dw^?1 in the PMOB and RS, respectively. From these results, the PMOB was found to be a good technology to enhance methane oxidation, as its performance was clearly better than the starting soil that was present in the landfill site.     

Support for maternal manipulation of developmental nutrition in a facultatively eusocial bee, <Emphasis Type="Italic">Megalopta genalis</Emphasis> (Halictidae)

Developmental maternal effects are a potentially important source of phenotypic variation, but they can be difficult to distinguish from other environmental factors. This is an important distinction within the context of social evolution, because if variation in offspring helping behavior is due to maternal manipulation, social selection may act on maternal phenotypes, as well as those of offspring. Factors correlated with social castes have been linked to variation in developmental nutrition, which might provide opportunity for females to manipulate the social behavior of their offspring. Megalopta genalis is a mass-provisioning facultatively eusocial sweat bee for which production of males and females in social and solitary nests is concurrent and asynchronous. Female offspring may become either gynes (reproductive dispersers) or workers (non-reproductive helpers). We predicted that if maternal manipulation plays a role in M. genalis caste determination, investment in daughters should vary more than for sons. The mass and protein content of pollen stores provided to female offspring varied significantly more than those of males, but volume and sugar content did not. Sugar content varied more among female eggs in social nests than in solitary nests. Provisions were larger, with higher nutrient content, for female eggs and in social nests. Adult females and males show different patterns of allometry, and their investment ratio ranged from 1.23 to 1.69. Adult body weight varied more for females than males, possibly reflecting increased variation in maternal investment in female offspring. These differences are consistent with a role for maternal manipulation in the social plasticity observed in M. genalis.     

Predicting occurrence of juvenile shark habitat to improve conservation planning

Fishing and habitat degradation have increased the extinction risk of sharks, and conservation strategies recognize that survival of juveniles is critical for the effective management of shark populations. Despite the rapid expansion of marine protected areas (MPAs) globally, the paucity of shark‐monitoring data on large scales (100s–1000s km) means that the effectiveness of MPAs in halting shark declines remains unclear. Using data collected by baited remote underwater video systems (BRUVS) in northwestern Australia, we developed generalized linear models to elucidate the ecological drivers of habitat suitability for juvenile sharks. We assessed occurrence patterns at the order and species levels. We included all juvenile sharks sampled and the 3 most abundant species sampled separately (grey reef [Carcharhinus amblyrhynchos], sandbar [Carcharhinus plumbeus], and whitetip reef sharks [Triaenodon obesus]). We predicted the occurrence of juvenile sharks across 490,515 km² of coastal waters and quantified the representation of highly suitable habitats within MPAs. Our species‐level models had higher accuracy (? ≥ 0.69) and deviance explained (≥48%) than our order‐level model (? = 0.36 and deviance explained of 10%). Maps of predicted occurrence revealed different species‐specific patterns of highly suitable habitat. These differences likely reflect different physiological or resource requirements between individual species and validate concerns over the utility of conservation targets based on aggregate species groups as opposed to a species‐focused approach. Highly suitable habitats were poorly represented in MPAs with the most restrictions on extractive activities. This spatial mismatch possibly indicates a lack of explicit conservation targets and information on species distribution during the planning process. Non‐extractive BRUVS provided a useful platform for building the suitability models across large scales to assist conservation planning across multiple maritime jurisdictions, and our approach provides a simple for method for testing the effectiveness of MPAs.     

Dispersion by wind of CO2 leaking from underground storage: Comparison of analytical solution with simulation

The concentration of CO₂ in air near the ground needs to be predicted to assess environmental and health risks from leaking underground storage. There is an exact solution to the advection–diffusion equation describing trace gases carried by wind when the wind profile is modeled with a power-law dependence on height. The analytical solution is compared with a numerical simulation of the coupled air–ground system with a source of CO₂ underground at the water table. The two methods produce similar results far from the boundaries, but the boundary conditions have a strong effect; the simulation imposes boundary conditions at the edge of a finite domain while the analytic solution imposes them at infinity. The reverse seepage from air to ground is shown in the simulation to be very small, and the large difference between time scales suggests that air and ground can be modeled separately, with gas emissions from the ground model used as inputs to the air model.     

Integrating Top-Down with Bottom-Up Conservation Policy in Africa

Abstract:  Developed nations intervened in conservation policy across Africa during the 20th century to address needs to protect species and biodiversity that were based on their own perceptions and priorities. In the 21st century, conservationists in Africa have revised these perceptions and begun the process of identifying conservation priorities from an African perspective and in consideration of Africans' priorities. Although foreign conservation interveners struggled to identify mechanisms to which local people would respond, African conservationists are now demonstrating how to integrate the continent's unique socioeconomic circumstances into efforts to protect biodiversity. In Africa effective conservation policy must include the generation of wealth, reduction of disease and hunger, and support of traditional land-use practices.     

Impact of “Designated Smoking Area” Policy on Nicotine Vapor and Particle Concentrations in a Modern Office Building

A series of measurements of nicotine vapor and particle concentrations were carried out in a modern office building. The measurement program was designed to document the impact of the new smoking policy (e.g. smoking restricted to two specific areas) on air quality in various parts of the building.

Measurements at over 30 locations examined areas where smoking was restricted, where smoking was permitted, and where an air handler shared the load of a designated smoking area. These measurements were taken at the same locations before and after the policy was Implemented.

The measurement results Indicated that: ? After the policy was implemented, general employee exposure to nicotine vapor (as a surrogate for all environmental tobacco smoke) was reduced by about 98 percent on most floors. Other patterns related to spillover from designated smoking areas and changes in the designated smoking areas themselves are described in the paper.

? Substantial reductions in exposure to nicotine vapor were found even for those general office areas which had the highest concentrations after the policy was implemented.

     

Emissions concerns during renovation in the healthcare setting: Asbestos abatement of floor tile and mastic in medical facilities

Healthcare facilities undergoing renovation have specific concerns that are exacerbated when the restoration requires asbestos abatement of aged floor tile and mastic. The current state of the art for removal of these materials involves manual removal of floor tile and chemical stripping of mastic. Utilization of these stripping chemicals is a concern for facilities whose perception is based on a safe, caring, and healthy environment. In this study, wet grinding is evaluated as an alternative to chemical stripping of asbestos-containing floor tile mastic. This study endeavors to answer the question; what is the difference between these two methodologies in terms of their operational efficacy and suitability in the healthcare setting. Wet grinding and chemical stripping are evaluated in a side-by-side comparison using a mixed methods approach. The data shows that the methodologies are statistically similar in terms of their cost and emissions data. The data indicates that the benefits associated with the wet grinding method offer advantages that are not present using the chemical stripping method. This study also demonstrates that wet grinding is a viable alternative to chemical stripping especially in healthcare facilities.