Exposure to Air Pollution in Rural Malawi: Impact of Cooking Methods on Blood Pressure and Peak Expiratory Flow

We made static and personal PM2.5 measurements with a miniature monitor (RTI MicroPEM) to characterise the exposure of women cooking with wood and charcoal in indoor and outdoor locations in rural Malawi, together with measurements of blood pressure and peak expiratory flow rate (PEFR). Mean PM2.5 concentrations of 1338 and 31 µg/m3 were observed 1 m from cookstove locations during cooking with wood and charcoal, respectively. Similarly, mean personal PM2.5 exposures of 706 and 94 µg/m3 were observed during cooking with wood and charcoal, respectively. Personal exposures to PM2.5 in indoor locations were 3.3 and 1.7 times greater than exposures observed in equivalent outdoor locations for wood and charcoal, respectively. Prior to the measured exposure, six out of eight participants had PEFR observations below 80% of their expected (age and height) standardised PEFR. We observed reductions in PEFR for participants cooking with wood in indoor locations. Five out of eight participants reported breathing difficulties, coughing, and eye irritation when cooking with wood but reported that symptoms were less severe when cooking with charcoal. In conclusion, we observed that exposure to PM2.5 was substantially reduced by cooking outdoor with charcoal. As both wood and charcoal fuels are associated with negative environmental and health impacts, the adoption of high-efficiency cookstoves and less polluting sources of energy will be highly beneficial. Cooking outside whenever possible, and minimising the time spent in close proximity to stoves, may be simple interventions that could reduce the risks of exacerbation and progression of respiratory and cardiovascular diseases in Malawi.

METHOD FOR ESTIMATING THE MEASURED EXPOSURE RATE OVER THE THYROID CORRESPONDING TO CERTAIN LEVELS OF THE ABSORBED DOSE IN THE THYROID FOR THE PUBLIC IN THE EARLY PERIOD AFTER A LARGE RADIATION ACCIDENT

In case of a large radiation accident at the nuclear power station the most important radiation hazard for the public is internal exposure to the thyroid from radioiodine. The IAEA standard published in 2013 and accounting the experience of the Chernobyl and Fukushima accidents, recommends that, in the first 1-6 days after an inhalation intake of radioiodine the exposure rate over the thyroid be measured for the public and be guided by the following operational criteria: (a) 0.5 μSv · h-1 for children under the age of 7 years, and (b) 2 μSv ·h-1 for children over 7 years and adults. These operational criteria are indicative estimates corresponding to the dose range 100–200 mGy in the thyroid for all age groups. However, a wider range of thyroid doses and a more detailed breakdown of children into five age groups according to the recommendations of the ICRP are of interest. The purpose of this paper is to develop a method for estimating the values of the measured exposure rate over the thyroid corresponding to certain levels of the absorbed dose in the thyroid for members of the public of different ages for various conditions of inhalation of radioiodine intake and times of measurement in the early period after a radiation accident. According to the method developed in the paper for the committed absorbed dose 100-200 mGy in the thyroid the exposure rates over the thyroid were calculated depending upon the time of inhalation intake after the accident and the time span between the moment of intake and the moment of measurement, which were equal to: 0.6– 4 μSv ·h-1 - for children of 1 year and 4–27 μSv · h-1 – for adults. These values are significantly higher than those recommended by the IAEA Standard 0.5 μSv · h-1 and 2 μSv · h-1, respectively. It is important to stress that the IAEA recommendations provide conservative estimates of the measured exposure rate over the thyroid in order to maximize the coverage of critical group of the public for further dosimetric and medical examination. For example, for some options of the time of radioiodine inhalation intake and the time of measurement, the IAEA recommended the values of the exposure rate over the thyroid that can lead to an overestimation of the absorbed dose in the thyroid gland by a factor of up to 10.

Measuring neighborhood deprivation for childhood health and development - scale implications in rural and urban context

Neighborhood deprivation plays an important role in childhood health and development, but defining the appropriate neighborhood definition presents theoretical as well as practical challenges. Few studies have compared neighborhood definitions outside of highly urbanized settings. The purpose of the current study was to evaluate how various administrative and ego-centric neighborhood definitions may impact measured exposure to deprivation across the urban-rural continuum. We do so using the Family Life Project, a prospective longitudinal population-based sample of families living in North Carolina and Pennsylvania (USA), which also sets the stage for future investigations of neighborhood impacts on childhood health and development. To measure neighborhood deprivation, a standardized index of socioeconomic deprivation was calculated using data from the 2007-2011 American Community Survey. Families’ residential addresses when children were 2 months of age (n=1036) were geocoded and overlaid onto a deprivation index layer created at the census block group level to construct multiple administrative and ego-centric neighborhood definitions. Friedman tests were used to compare distributions of neighborhood deprivation across these neighborhood definitions within urbanized areas, urban clusters, and rural areas. Results indicated differences in urbanized areas (Chisquare= 897.75, P<0.001) and urban clusters (Chi-square=687.83, P<0.001), but not in rural areas (Chi-square=13.52, P=0.332). Findings imply that in urban areas, choice of neighborhood definition impacts measured exposure to neighborhood deprivation. Although exposure to neighborhood deprivation appears to be less sensitive to neighborhood definition in rural areas, researchers should apply theoretical reasoning to choose appropriate definitions of children’s neighborhood.

Extrapolating the Applicability of Measurement Data on Worker Inhalation Exposure to Chemical Substances

Measured data are generally preferred to modelled estimates of exposure. Grouping and read-across is already widely used and accepted approach in toxicology, but an appropriate approach and guidance on how to use existing exposure measurement data on one substance and work situation for another substance and/or work situation is currently not available. This study presents a framework for an extensive read-across of existing worker inhalable exposure measurement data. This framework enables the calculation of read-across factors based on another substance and/or work situation by first evaluating the quality of the existing measurement data and then mapping its similarity or difference with another substance and/or work situation. The system of read-across factors was largely based on the determinants in ECETOC TRA and ART exposure models. The applicability of the framework and its proof of principle were demonstrated by using five case studies. In these case studies, either the 75th percentiles of measured exposure data was observed to lie within the estimated 90% confidence intervals from the read-across approach or at least with the increase in the geometric mean of measured exposure, geometric mean of estimated exposure also increased. Testing and re-evaluation of the present framework by experts in exposure assessment and statistics is recommended to develop it further into a tool that can be widely used in exposure assessment and regulatory practices.

Hot and bothered: effects of elevated Pco2 and temperature on juvenile freshwater mussels

Multiple environmental stressors may interact in complex ways to exceed or diminish the impacts of individual stressors. In the present study, the interactive effects of two ecologically relevant stressors [increased temperature and partial pressure of carbon dioxide (Pco2)] were assessed for freshwater mussels, a group of organisms that are among the most sensitive and rapidly declining worldwide. The individual and combined effects of elevated temperature (22°C–34°C) and Pco2 (~230, 58,000 µatm) on juvenile Lampsilis siliquoidea were quantified over a 5- or 14-day period, during which physiological and whole animal responses were measured. Exposure to elevated temperature induced a series of physiological responses, including an increase in oxygen consumption rates following 5 days of exposure at 31°C and an increase in carbonic anhydrase ( ca) and heat shock protein 70 mRNA levels following 14 days of exposure at 28°C and 34°C, respectively. Treatment with elevated Pco2 activated acid-base regulatory responses including increases in CA and Na+-K+-ATPase activity and a novel mechanism for acid-base regulation during Pco2 exposure in freshwater mussels was proposed. Thermal and CO2 stressors also interacted such that responses to the thermal stressor were diminished in mussels exposed to elevated Pco2, resulting in the greatest level of mortality. Additionally, larger mussels were more likely to survive treatment with elevated Pco2 and/or temperature. Together, exposure to elevated Pco2 may compromise the ability of juvenile freshwater mussels to respond to additional stressors, such as increased temperatures, highlighting the importance of considering not only the individual but also the interactive effects of multiple environmental stressors.

Noise exposure of a tractor driver at skidding of wood assortments in hilly-mountaineous areas

The first phase of transport of forest products (skidding) in Serbia is usually performed by skid trails with adapted agricultural tractors. The educational base ?Goc - Gvozdac? compartment 21 was the selected object of this research. Data recording was carried out in June 2011. The vehicle driven by the driver was an IMT 565 DV tractor. The organizational form of work was 1T + 1P (tractor driver and assistant). The microphone of a Bruel & Kjaer 4189 noise measuring instrument was mounted on the helmet of the tractor driver in accordance with the ISO 9612: 2012 standard. The recording was performed with a Bruel & Kjaer 2250 instrument. The values of the following parameters with appropriate filters: LAeq (dB(A)), LAIeq (dB(A)), LCpeak (dB(C)), LZeq (dB) were measured. The measured exposure of the workers to noise was the highest in the course of the main productive time (empty or full drive). It was found that the eight-hour exposure to noise of the driver (88 dB (A)) exceeds the limit value of daily exposure according to European legislation. The results show that it is necessary for drivers to use hearing protection equipment when transporting wood with the studied transportation vehicle.

PUFA-dependent alteration of oxidative parameters of a canine mastocytoma cell line

Mast cells play a key role in the immune response. Thereby, the balance of oxidative metabolism is of importance in mast cell mediator synthesis and release. Fatty acids may modify mast cell function in several ways. In this study, we investigated the influence of polyunsaturated fatty acids (PUFAs) on oxidative parameters of a canine mastocytoma cell line. C2 cells were cultured in media supplemented with linoleic acid, arachidonic acid, alpha-linolenic acid and eicosapentaenoic acid, respectively. Production of reactive oxygen species (ROS) as well as lipid peroxides was tested. Furthermore, stressor-induced DNA damage was measured. Exposure of the cells to PUFAs resulted in a significant increase in the synthesis of both ROS and lipid peroxides. Distinct differences between the PUFAs tested underline the impact of the unsaturation degree of fatty acids as well as the position of double bonds on mast cells.