Should we ignore U-235 series contribution to dose?

Environmental Risk Assessment (ERA) methodology for radioactive substances is an important regulatory tool for assessing the safety of licensed nuclear facilities for wildlife, and the environment as a whole. ERAs are therefore expected to be both fit for purpose and conservative. When uranium isotopes are assessed, there are many radioactive decay products which could be considered. However, risk assessors usually assume 235U and its daughters contribute negligibly to radiological dose. The validity of this assumption has not been tested: what might the 235U family contribution be and how does the estimate depend on the assumptions applied? In this paper we address this question by considering aquatic wildlife in Canadian lakes exposed to historic uranium mining practices. A full theoretical approach was used, in parallel to a more realistic assessment based on measurements of several elements of the U decay chains. The 235U family contribution varied between about 4% and 75% of the total dose rate depending on the assumptions of the equilibrium state of the decay chains. Hence, ignoring the 235U series will not result in conservative dose assessments for wildlife. These arguments provide a strong case for more in situ measurements of the important members of the 235U chain and for its consideration in dose assessments

Standardising Visual Control Devices for Tsetse Flies: Central and West African Species <i>Glossina palpalis palpalis</i>

Background: Glossina palpalis palpalis (G. p. palpalis) is one of the principal vectors of sleeping sickness and nagana in Africa with a geographical range stretching from Liberia in West Africa to Angola in Central Africa. It inhabits tropical rain forest but has also adapted to urban settlements. We set out to standardize a long-lasting, practical and cost-effective visually attractive device that would induce the strongest landing response by G. p. palpalis for future use as an insecticide impregnated tool in area-wide population suppression of this fly across its range. Methodology/Principal Findings: Trials were conducted in wet and dry seasons in the Ivory Coast, Cameroon, the Democratic Republic of Congo and Angola to measure the performance of traps (biconical, monoconical and pyramidal) and targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used as a practical enumerator at these remote locations to compare landing efficiencies of devices. Independent of season and country, both phthalogen blue-black and blue-black-blue 1 m2 targets covered with adhesive film proved to be as good as traps in phthalogen blue or turquoise blue for capturing G. p. palpalis. Trap efficiency varied (8–51%). There was no difference between the performance of blue-black and blue-blackblue 1 m2 targets. Baiting with chemicals augmented the overall performance of targets relative to traps. Landings on smaller phthalogen blue-black 0.25 m2 square targets were not significantly different from either 1 m2 blue-black-blue or blue-black square targets. Three times more flies were captured per unit area on the smaller device. Conclusions/Significance:Blue-black 0.25 m2 cloth targets show promise as simple cost effective devices for management of G. p. palpalis as they can be used for both control when impregnated with insecticide and for population sampling when covered with adhesive film

Optimizing the colour and fabric of targets for the control of the tsetse fly Glossina fuscipes fuscipes

Background: Most cases of human African trypanosomiasis (HAT) start with a bite from one of the subspecies of Glossina fuscipes. Tsetse use a range of olfactory and visual stimuli to locate their hosts and this response can be exploited to lure tsetse to insecticide-treated targets thereby reducing transmission. To provide a rational basis for cost-effective designs of target, we undertook studies to identify the optimal target colour. Methodology/Principal Findings: On the Chamaunga islands of Lake Victoria , Kenya, studies were made of the numbers of G. fuscipes fuscipes attracted to targets consisting of a panel (25 cm square) of various coloured fabrics flanked by a panel (also 25 cm square) of fine black netting. Both panels were covered with an electrocuting grid to catch tsetse as they contacted the target. The reflectances of the 37 different-coloured cloth panels utilised in the study were measured spectrophotometrically. Catch was positively correlated with percentage reflectance at the blue (460 nm) wavelength and negatively correlated with reflectance at UV (360 nm) and green (520 nm) wavelengths. The best target was subjectively blue, with percentage reflectances of 3%, 29%, and 20% at 360 nm, 460 nm and 520 nm respectively. The worst target was also, subjectively, blue, but with high reflectances at UV (35% reflectance at 360 nm) wavelengths as well as blue (36% reflectance at 460 nm); the best low UV-reflecting blue caught 3× more tsetse than the high UV-reflecting blue. Conclusions/Significance: Insecticide-treated targets to control G. f. fuscipes should be blue with low reflectance in both the UV and green bands of the spectrum. Targets that are subjectively blue will perform poorly if they also reflect UV strongly. The selection of fabrics for targets should be guided by spectral analysis of the cloth across both the spectrum visible to humans and the UV region

Standardizing Visual Control Devices for Tsetse Flies: West African Species Glossina tachinoides, G. palpalis gambiensis and G. morsitans submorsitans

Here we describe field trials designed to standardize tools for the control of Glossina tachinoides, G. palpalis gambiensis and G.morsitans submorsitans in West Africa based on existing trap/target/bait technology. Blue and black biconical and monoconical traps and 1 m2 targets were made in either phthalogen blue cotton, phthalogen blue cotton/polyester or turquoise blue polyester/viscose (all with a peak reflectance between 450–480 nm) and a black polyester. Because targets were covered in adhesive film, they proved to be significantly better trapping devices than either of the two trap types for all three species (up to 14 times more for G. tachinoides, 10 times more for G. palpalis gambiensis, and 6.5 times for G. morsitans submorsitans). The relative performance of the devices in the three blue cloths tested was the same when unbaited or baited with a mixture of phenols, 1-octen-3-ol and acetone. Since insecticide-impregnated devices act via contact with flies, we enumerated which device (traps or targets) served as the best object for flies to land on by also covering the cloth parts of traps with adhesive film. Despite the fact that the biconical trap proved to be the best landing device for the three species, the difference over the target (20–30%) was not significant. This experiment also allowed an estimation of trap efficiency, i.e. the proportion of flies landing on a trap that are caught in its cage. A low overall efficiency of the biconical or monoconical traps of between 11–24% was recorded for all three species. These results show that targets can be used as practical devices for population suppression of the three species studied. Biconical traps can be used for population monitoring, but a correction factor of 5–10 fold needs to be applied to captures to compensate for the poor trapping efficiency of this device for the three species

Addressing ecological effects of radiation on populations and ecosystems to improve protection of the environment against radiation: Agreed statements from a Consensus Symposium

This paper reports the output of a consensus symposium organized by the International Union of Radioecology in November 2015. The symposium gathered an academically diverse group of 30 scientists to consider the still debated ecological impact of radiation on populations and ecosystems. Stimulated by the Chernobyl and Fukushima disasters' accidental contamination of the environment, there is increasing interest in developing environmental radiation protection frameworks. Scientific research conducted in a variety of laboratory and field settings has improved our knowledge of the effects of ionizing radiation on the environment. However, the results from such studies sometimes appear contradictory and there is disagreement about the implications for risk assessment. The Symposium discussions therefore focused on issues that might lead to different interpretations of the results, such as laboratory versus field approaches, organism versus population and ecosystemic inference strategies, dose estimation approaches and their significance under chronic exposure conditions. The participating scientists, from across the spectrum of disciplines and research areas, extending also beyond the traditional radioecology community, successfully developed a constructive spirit directed at understanding discrepancies. From the discussions, the group has derived seven consensus statements related to environmental protection against radiation, which are supplemented with some recommendations. Each of these statements is contextualized and discussed in view of contributing to the orientation and integration of future research, the results of which should yield better consensus on the ecological impact of radiation and consolidate suitable approaches for efficient radiological protection of the environment.Keywords: Consensus development, Environmental protection, Populations, Radiation effects, Ecosystems, Ecological risk assessmen

Breeding performance in captivity of meadow voles (<i>Microtus pennsylvanicus</i>) from decline- and increase-phase populations

A major enigma in understanding microtine cycles is the failure of decline-phase animals to increase. We compared the performance of wild-caught meadow voles and their progeny from Pinawa, Manitoba, collected from a decline year (1985) with mat of animals from an increase year (1986) by breeding them in the laboratory in Pinawa (animals from both years) and in the field and laboratory in Toronto (only F1 and F2 animals from 1985). Overall only 35% of the 1985 females or their progeny bred in the laboratory in Pinawa compared with 100% of the 1986 females. The interval between pairing with a male and birth of litters was 2 -7 months for the 1985 females compared with 3 -4 weeks fur the 1986 females. The poor breeding performance of 1985 females occurred only in the laboratory; in small field enclosures in Toronto all F1 and F2 females conceived and had litters within 3-4 weeks. In contrast, 1985 males readily sired litters either with 1986 females in the laboratory or with Toronto females in the field. We conclude that the prior experience of decline-phase females had long-term detrimental consequences for the performance of the first two generations under laboratory conditions

Habitat Preferences and Activity Patterns of Glossina swynnertoni Austen (Diptera: Glossinidae) in Aitong, Masai Mara, Kenya

The habitat preferences and activity patterns of Glossina swynnertoni Austen were studied using Siamese traps, electrified screens and vehicle patrols in Aitong, southwestern Kenya in three habitats: large thicket, wooded grassland and an Acacia community. Except in the Acacia community, G.swynnertoni occurred in association with Glossina pallidipes Austen. Apparent density varied significantly among the three habitats, being highest in the Acacia community, intermediate in wooded grassland and lowest in large thickets. Density also varied seasonally, with higher densities occurring in the rainy season than in the dry season in all three areas. Vehicle patrol was a more effective and rapid method for sampling G. swynnertoni than either Siamese traps or electrified screens. However, vehicle patrol catches were strongly biased in favour of males (4:1). Diurnal activity in the Acacia community was unimodal for both sexes, with peaks of activity occurring at 1100-1200 h for males and at 1400-1500 h for females. Both sexes remained active in the afternoon but activity declined rapidly towards dusk (1700-1800h). RÉSUMÉ Lespréférences d'habitat et les rythmes d'activité de Glossina swynnertoni Austen ont été étudiés à l'aide de pièges de Siamese, d'écrans électrifiés et de récoltes (patrouilles) en voiture, à Aitong, dans le Sud-ouest du Kenya dans trois habitats des grands bosquets, de la savane arborée et une forêt d'acacias. A l'exception de la forêt d'acacias, G. swynnertoni est rencontrée en association avec G. pallidipes Austen. La densité apparente varie significativement entre les trois habitats; elles est la plus forte dans la forêt d'acacias, intermédiaire en savane arborée et plus faible dans les grands bosquets. La densité varie également avec la saison, avec de plus fortes densités observées en saison des pluies par rapport à la saison sèche dans les trois habitats. Les captures réalisées lors des patrouilles en voiture sont plus efficaces et rapides pour l'échantillonnage de G. swynnertoni que les pièges de Siamese, et que les écrans électrifiés; ces captures sont cependant fortement biaisées en faveur des mâles (4:1). L'activité diurne dans la forêt d'acacias est unimodale pour les deux sexes, avec des pics d'activité entre 1100-1200 h pour les mâles et 1400-1500h pour les femelles. Les deux sexes restent actifs dans l'après-midi mais l'activité décline rapidementvers le crépuscule (1700-1800h)