Internal dose rate due to intake of uranium and thorium by fish from a dam reservoir associated with a uranium mine in Brazil.

Uranium mining can cause environmental impacts on non-human biota around mine sites. Because of this, the reduction in non-human biota exposure becomes an important issue. Environmental radioprotection results from the evolution of human radioprotection; it is based on dose rate to non-human biota and uses, as a biological target, and has harmful effects on populations. In the present study, a flooded impoundment created following dam construction in a uranium mine plant undergoing decommissioning was investigated. Internal dose rates due to activity concentration of natural uranium (Unat) and 232Th in omnivorous, phytophagous, and carnivorous fish species were estimated. Radionuclide activity concentrations were obtained by spectrophotometry with arsenazo III in the visible range. The dose rate contribution of 232Th was lower than that of Unat. There were no differences between the internal dose rates to studied fish species due to 232Th, but there were differences for Unat. A dose rate of 2.30·10-2 µGy∙d-1 was found due to the two studied radionuclides. Although this value falls below the benchmark for harmful effects, it is important to acknowledge that the assessment did not account for other critical radionuclides from uranium mining, which also contribute to the internal dose. Moreover, the study did not assess external doses. As a result, the possibility cannot be excluded that dose rates at the study area overcome the established benchmarks for harmful effects.

Exploring the Insecticide and Acaricide Potential of Development Regulators obtained from Restinga vegetation from Brazil.

As a part of our continuing search for insect and arthropod development regulators from Brazilian restinga vegetation of the Rio de Janeiro State, crude extracts, purified fractions and essential oils were submitted to screening tests seeking for biological activities on the development of the insects Rhodnius prolixus, Dysdercus peruvianus, Oncopeltus fasciatus and Rhipicephalus (Boophilus) microplus. Up to now, 102 secondary metabolites have been detected in the fractions, among them monoterpenes, sesquiterpenes and two triterpenes which were obtained from the species, Eugenia sulcata, Pilocarpus spicatus, Manilkara subsericea, Myrciaria floribunda and Zanthoxylum caribaeum. These secondary plant metabolites are considered of interest for the use of studies related to arthropod endocrinology, vector-parasite interaction system, and population control of vector insect and agricultural pest. The observed biological activities were surprisingly high, involving increased mortality, molting and metamorphosis inhibition, paralysis, corporeal deformities, apparition of permanent nymphs, of adultoids and juvenoids, partial or total inhibition of oviposition and egg hatching. These compounds are now being studied further to determine if they may or may not be useful in controlling insect populations and/or interfere with the life cycle and vector transmission of parasites to animal and human populations.

Mevalonosomes: specific vacuoles containing the mevalonate pathway in Plocamium brasiliense cortical cells (Rhodophyta).

This paper has identified, for the first time in a member of the Rhodophyta, a vacuolar organelle containing enzymes that are involved in the mevalonate pathway-an important step in red algal isoprenoid biosynthesis. These organelles were named mevalonosomes (Mev) and were found in the cortical cells (CC) of Plocamium brasiliense, a marine macroalgae that synthesizes several halogenated monoterpenes. P. brasiliense specimens were submitted to a cytochemical analysis of the activity of the 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS). Using transmission electron microscopy (TEM), we confirmed the presence of HMGS activity within the Mev. Because HMGS is necessary for the biosynthesis of halogenated monoterpenes, we isolated a hexanic fraction (HF) rich in halogenated monoterpenes from P. brasiliense that contained a pentachlorinated monoterpene as a major metabolite. Because terpenes are often related to chemical defense, the antifouling (AF) activity of pentachlorinated monoterpene was tested. We found that the settlement of the mussel Perna perna was reduced by HF treatment (2.25 times less than control; 40% and 90% of fouled surface, respectively; P = 0.001; F9,9 = 1.13). The HF (at 10 µg · mL(-1) ) also inhibited three species of fouling microalgae (Chlorarachnion reptans, Cylindrotheca cloisterium, and Exanthemachrysis gayraliae), while at a higher concentration (50 µg · mL(-1) ), it inhibited the bacteria Halomonas marina, Polaribacter irgensii, Pseudoalteromonas elyakovii, Shewanella putrefaciens, and Vibrio aestuarianus. The AF activity of P. brasiliense halogenated monoterpenes and the localization of HMGS activity inside Mev suggest that this cellular structure found in CC may play a role in thallus protection against biofouling.

Environmental impact assessment due to the intake of uranium contained in surface waters in a semi-arid region in Brazil.

In Santa Quitéria City, part of the population uses surface water for potation. These waters do not undergo any treatment before consumption. As the region has a deposit of uranium, assessing water quality becomes important. In the present study, the uranium activity concentration (AC) in becquerels per liter was determined in water samples from six points. Univariate statistics showed differences between the soluble and the particulate fraction (soluble AC > particulate AC). The particulate fraction showed no variation in AC among the six points. On the other hand, the soluble fraction and the total fraction presented different ACs between them. The multivariate statistics allowed to separate the soluble from the particulate fraction of the points. The same tools applied to the total fraction made it possible to differentiate the sampling points, grouping them ((#1, #2); (#3, #4), and (#5, #6)). The maximum mean value of AC found was 0.177 Bq∙L-1, corresponding to 25% of the chemical toxicity limit (0.72 Bq∙L-1). The maximum mean dose rate, 2.25 µSv∙year-1, is lower than the considered negligible dose rate (> 10 µSv∙year-1). The excess lifetime cancer risk was 10-6, two orders of magnitude smaller than the threshold considered for taking action. The assessment parameters used in this work indicate that the risk due to the uranium intake by the local population is negligible.

Chemical Defense against Herbivory in the Brown Marine Macroalga Padina gymnospora Could Be Attributed to a New Hydrocarbon Compound.

Brown marine macroalga Padina gymnospora (Phaeophyceae, Ochrophyta) produces both secondary metabolites (phlorotannins) and precipitate calcium carbonate (CaCO3-aragonite) on its surface as potential defensive strategies against herbivory. Here, we have evaluated the effect of natural concentrations of organic extracts (dichloromethane-DI; ethyl acetate-EA and methanol-ME, and three isolated fractions) and mineralized tissues of P. gymnospora as chemical and physical resistance, respectively, against the sea urchin Lytechinus variegatus through experimental laboratory feeding bioassays. Fatty acids (FA), glycolipids (GLY), phlorotannins (PH) and hydrocarbons (HC) were also characterized and/or quantified in extracts and fractions from P. gymnospora using nuclear magnetic resonance (NMR) and gas chromatography (GC) coupled to mass spectrometry (CG/MS) or GC coupled to flame ionization detector (FID) and chemical analysis. Our results showed that chemicals from the EA extract of P. gymnospora were significantly important in reducing consumption by L. variegatus, but the CaCO3 did not act as a physical protection against consumption by this sea urchin. An enriched fraction containing 76% of the new hydrocarbon 5Z,8Z,11Z,14Z-heneicosatetraene exhibited a significant defensive property, while other chemicals found in minor amounts, such as GLY, PH, saturated and monounsaturated FAs and CaCO3 did not interfere with the susceptibility of P. gymnospora to L. variegatus consumption. We suggest that the unsaturation of the 5Z,8Z,11Z,14Z-heneicosatetraene from P. gymnospora is probably an important structural characteristic responsible for the defensive property verified against the sea urchin.

Application of radiological assessment as water quality criterion for effluent release in a Brazilian uranium mine.

Uranium mining causes several radiological impacts on the surrounding environment, notably in the water bodies, mainly due to the release of long half-life radionuclides from the 238U and 232Th series. The Ore Treatment Unit, an old uranium mine undergoing decommissioning, has three points of liquid effluent release (#014, #025, and #076). For current study, 78 samples of water were collected at #014, 33 samples at #025, and 63 samples at #076. The radionuclides were analyzed by gross alpha count, gross beta count, and by arsenazo spectrophotometry. Analyses were carried out using the radiological water quality criterion established by World Health Organization and other organizations, together with the Brazilian legislation, to assess if the released effluents may be used unrestrictedly by the individuals of the public. At #014, the mean values of activity concentration (AC), in Bq·L-1, were as follows: Unat = 0.107, 226Ra = 0.035, 210Pb = 0.031, 232Th = 0.007, and 228Ra = 0.049. At #025 the mean values of AC, in Bq·L-1, were as follows: Unat = 0.086, 226Ra = 0.015, 210Pb = 0.028, 232Th = 0.006, and 228Ra = 0.032. Finally, at point #076, the mean AC values, in Bq·L-1, were as follows: Unat = 3.624, 226Ra = 0.074, 210Pb = 0.054, 232Th = 0.013, and 228Ra = 0.069. The current study showed that natural radionuclides were not in secular equilibrium. Despite uranium presented its values outside the limits of guidance levels, it can be state that the unrestricted use of effluents released in the three water bodies is authorized from the radiological point of view. In terms of dose rate, the releases at three points were within the radiological limits of potability. On the other hand, in an additional analysis, #76 presented chemical toxicity above the authorized value, pointing the need of restricted use of water from the point of view of chemical toxicity.

Excess lifetime cancer risk due to ingestion of fish from a dam reservoir associated with a nuclear facility in Brazil.

Fish from a Funil dam reservoir associated with a Nuclear Fuel Factory were sampled aiming to assess the radiological risk due to ingestion. Funil dam reservoir is a strategic site, once it receives effluent from the industrial complex that performs isotopic enrichment of uranium and conversion of UF6. The mean activity concentrations obtained for 40K, 226Ra, 228Ra and 228Th were 57.81, 0.41, 0.92 and 0.49 Bq·kg-1, respectively. Lifetime cancer risk was estimated in ∼10-5 and no action needs to be taken.

Assessment of released natural radionuclides by waste rock pile and mining pit associated with a uranium mine at Caldas, Minas Gerais, Brazil.

The Ore Treatment Unit was a uranium mining company that is currently being decommissioned. The local rainfall index makes it necessary to release effluents into the environment. After releasing, the wastewater is available for unrestricted use. Current study aims to use national and international recommendations to assess the radiological potability of released effluents at one of the three points of company's interface with the environment. Twenty-four samples of water were collected and activity concentrations (AC) were obtained by gross alpha count, gross beta count, and for arsenazo spectrophotometry. Statistical analysis techniques were applied to the data with the purpose of understanding the results for the soluble, particulate, and total fractions. The mean AC for effluents were 3.580, 0.082, 0.103, 0.063, and 0.090 Bq L-1 for Unat, 226Ra, 210Pb, 232Th, and 228Ra, respectively, for the total fraction. The analysis of variance pointed to Unat as a critical radionuclide, since it presented more than 90% of the total AC released into the environment. Pearson's R2 pointed to soluble fraction as a major contributor to the total AC released. The guidance level proposed by WHO was used to assess the radiological potability of the effluents. The results obtained indicated the need for trigger other analyses. Committed effective dose was estimated due to the unrestricted use of effluents and the value obtained, 0.23 mSv year-1, was below the maximum allowed limit. Finally, the radiotoxicity of the released effluent was evaluated and the value obtained was ~ 50% of the maximum allowed limit. In conclusion, the present study showed that the level of radioactivity released into the environment by the Ore Treatment Unit does not present a radiological risk to the surrounding population.

Lifetime cancer risk increase due to consumption of some foods from a High Background Radiation Area.

Activity concentration (AC) in foods produced and commonly consumed in a High Background Radiation Area (HBRA) was analyzed. The AC were obtained by spectrophotometry and by the radiochemical separation method. The AC were up to 104 times higher than the AC for both UNSCEAR suggested values and non-HBRA. It was noted that the lifetime cancer risk was increased in 4 decimal places, taking the risk from the "statistically negligible range" (<10-6) to "middle range" (between 10-4 and 10-6).

Evaluation of the radiological quality of water released by a uranium mining in Brazil.

A mine in an area of naturally occurring radioactive materials (NORM), characterized by acid mine drainage, generates effluents with natural radionuclide concentrations, usually above the limits authorized by the regulator. The plant exploiting NORM controls the water quality and discharges it into the aquatic environment after meeting technical requirements. Downstream, water usage is unrestricted. In order to reach activity concentrations in the released effluents below the authorized values, the facility applies a chemical treatment to the effluent. Then, to ensure the effectiveness of the treatment, the facility performs sampling of treated effluent and determines the activity concentration of natural radionuclides (Unat, 226Ra, and 210Pb from the uranium series and 232Th and 228Ra from the thorium series). In the current study, the proportion and distribution of these radionuclides between the soluble and particulate fractions were determined. The measured activity concentrations were compared with the values proposed by the World Health Organization and Brazilian legislation, as well as other authorities, as regards the potable use from the radioprotection point of view. It was observed that the radionuclides are not in secular equilibrium. The fractions contribute differently to the total release of radionuclide, and there is no linear relationship between the fractions. The average activity concentrations did not result in radiological restrictions to water use, and the committed effective dose due to ingestion was estimated at 0.06 mSv y-1. Therefore, there is no radiological restriction to water use, since the dose which was found was below the constraint value for the public.

Use of a bioindicator system in the study of the mutagenetical effects in the neighborhoods of deposits of radioactive waste.

The purpose of the research described in this paper was to analyze the biological mutational effects caused by low doses of ionizing radiation on biological samples placed nearby and around deposits of radioactive waste, as a way of monitoring the environment close to them. In order to do this, the plant Tradescantia pallida was chosen, and through micronuclei tests the sensitivity of the dose/response to bio-monitoring could be observed. The plants were exposed for a period of 24h in previously chosen sites around Brazil, within the proximity of nuclear waste deposits. In each location, three points were chosen for bio-monitoring. The results obtained at these locations showed a small increment in the frequency of micronuclei per cell of the biosensor. From these data, a scale of mutagenesis effects due to low-dose radiation was built up. T. pallida is a good alternative for environmental bio-monitoring in tropical climates, as it is an excellent alternative tool in the studies of the effects of ionizing radiation on the environment.

Assessment of uranium release to the environment from a disabled uranium mine in Brazil.

The Ore Treatment Unit (in Portuguese Unidade de Tratamento de Minérios - UTM) located in Caldas, MG, Brazil is a disabled uranium mine. Environmental conditions generate acid drainage leaching metals and radionuclides from the waste rock pile. This drainage is treated to remove the heavy metals and radionuclides, before allowing the release of the effluent to the environment. To validate the treatment, samples of the released effluents were collected at the interface of the installation with the environment. Sampling was carried out from 2010 to 2015, and the activity concentration (AC, in Bq·l-1) of uranium in the liquid effluent was analyzed by arzenazo UV-Vis spectrophotometry of the soluble and particulate fractions, and of the sum of both fractions. Descriptive statistics, Z test and Pearson R2 correlation among the fractions were performed. Then, the data were organized by year and both ANOVA and Tukey test were carried out to group the means by magnitude of AC. The annual mean ranged from 0.02 Bq·l-1 in 2015 to 0.11 Bq·l-1 in 2010. The soluble fraction showed a higher AC mean when compared to the mean of the particulate fraction and no correlation of the data could be observed. Concerning the magnitude of the release, the ANOVA associated with the Tukey test, identified three groups of annual means (AC2010> AC2011 = AC2012 = AC2013 = AC2014 > AC2015). The mean values of uranium release at the interface installation-environment checking point (point 014) were within the Authorized Annual Limit (AAL) set by the regulator (0.2 Bq·l-1) indicating compliance of treatment with the licensing established for the unit. Finally, the data showed a decreasing tendency of U release.

Development of a Larvicidal Nanoemulsion with Pterodon emarginatus Vogel Oil.

Pterodon emarginatus Vogel is a Brazilian species that belongs to the family Fabaceae, popularly known as sucupira. Its oil has several biological activities, including potent larvicidal property against Aedes aegypti. This insect is the vector of dengue, a tropical disease that has been considered a critical health problem in developing countries, such as Brazil. Most of dengue control methods involve larvicidal agents suspended or diluted in water and making active lipophilic natural products available is therefore considered a technological challenge. In this context, nanoemulsions appear as viable alternatives to solve this major problem. The present study describes the development of a novel nanoemulsion with larvicidal activity against A. aegypti along with the required Hydrophile Lipophile Balance determination of this oil. It was suggested that the mechanism of action might involve reversible inhibition of acetylcholinesterase and our results also suggest that the P. emarginatus nanoemulsion is not toxic for mammals. Thus, it contributes significantly to alternative integrative practices of dengue control, as well as to develop sucupira based nanoproducts for application in aqueous media.

Increase of 210Po levels in human semen fluid after mussel ingestion.

Polonium-210 ((210)Po) radioactive concentrations were determined in human semen fluid of vasectomized non-smoker volunteers. The (210)Po levels ranged from 0.10 to 0.39 mBq g(-1) (mean: 0.23 ± 0.08 mBq g(-1)). This value decreased to 0.10 ± 0.02 mBq g(-1) (range from 0.07 to 0.13 mBq g(-1)) after two weeks of a controlled diet, excluding fish and seafood. Then, volunteers ate during a single meal 200 g of the cooked mussel Perna perna L., and (210)Po levels were determined again, during ten days, in semen fluid samples collected every morning. Volunteers continued with the controlled diet and maintained sexual abstinence through the period of the experiment. A 300% increase of (210)Po level was observed the day following mussel consumption, with a later reduction, such that the level returned to near baseline by day 4.

Spectrally average conversion coefficients for air kerma to ambient dose equivalent for clinical linear accelerator.

This work aims to calculate the conversion coefficients from air kerma to ambient dose equivalent, H*(10)/K(air) for photon beams produced by linear accelerators, such as the Clinac-4, Clinac-6, Clinac-18 and Clinac-2500, after transmission through primary barriers of radiotherapy treatment rooms. Concrete walls of thickness 1.0, 1.5 and 2.0m were irradiated with 30cmx30cm primary beam spectra. The transmitted spectra were calculated to obtain the conversion coefficients for beams found in radiotherapy services. The calculations were done using the MCNP-4B Monte Carlo code. The results indicate the need to use a factor of about 1.20 to obtain the ambient dose equivalent for radiation surveys near primary barriers using instruments calibrated in air kerma.

Degradation of the neolignan, burchellin in the hemolymph of the bloodsucking insect Rhodnius prolixus.

The neolignan, burchellin, a natural compound that reduces urine excretion in larvae of the bloodsucking bug, Rhodnius prolixus, a vector of Chagas' disease, is rapidly degraded in the hemolymph of the insect. The main product that accumulates in this tissue has been shown to be piperonyl alcohol. Other catabolites have been identified by GC-MS analysis.

Secondary metabolites from marine microorganisms.

After 40 years of intensive research, chemistry of marine natural products has become a mature field. Since 1995, there are signals of decreased interest in the search of new metabolites from traditional sources such as macroalgae and octocorals, and the number of annual reports on marine sponges stabilized. On the contrary, metabolites from microorganisms is a rapidly growing field, due, at least in part, to the suspicion that a number of metabolites obtained from algae and invertebrates may be produced by associated microorganisms. Studies are concerned with bacteria and fungi, isolated from seawater, sediments, algae, fish and mainly from marine invertebrates such as sponges, mollusks, tunicates, coelenterates and crustaceans. Although it is still to early to define tendencies, it may be stated that the metabolites from microorganisms are in most cases quite different from those produced by the invertebrate hosts. Nitrogenated metabolites predominate over acetate derivatives, and terpenes are uncommon. Among the latter, sesquiterpenes, diterpenes and carotenes have been isolated; among nitrogenated metabolites, amides, cyclic peptides and indole alkaloids predominate.

A multidisciplinary approach to the study of the fluminense vegetation.

The fluminense vegetation, more specifically the flora from the Jurubatiba restinga has been investigated by a multidisciplinary team of botanists, chemist, radiobiologist, insect physiologists and geneticist. Vouchers of 564 specimens have been collected, identified, organized in an herbarium, and a database is being build up containing, in addition to classical botanical data, chemical data and information on the potential economic use either for landscape gardening, alternative foods or as medicinal plants. Phytochemical studies of the Guttiferae, Clusia hilariana, yielded oleanolic acid and nemorosone. Their biological activities against the haematophagous insect Rhodnius prolixus vector of Chagas disease have been investigated. Finally, it has been observed that aquatic plants possessed high levels of the natural radionuclide polonium-210, which seems to be originated mainly from soil rather than from atmospheric supply.

Melia azedarach L. extracts and their activity on Musca domestica L. (Diptera: Muscidae) / Extratos de Melia azedarach L. e sua atividade sobre Musca domestica L. (Diptera: Muscidae)

Crudes extracts and fractions from seeds of Melia azedarach L. (Meliaceae) have been assayed on Musca domestica Linnaeus, 1758 (Diptera: Muscidae). Thus, the post-embryonic development of the flies was reduced and the delay from newly hatched larvae to adults had significant increase. In addition, the pupal weights were reduced and the sexual ratio altered. Toxicity to fly eggs was also observed.

Os extratos brutos e as frações obtidas das sementes de Melia azedarach L. (Meliaceae) foram testados em Musca domestica Linnaeus, 1758 (Diptera: Muscidae). Os bioensaios mostraram inibição no desenvolvimento pós-embrionário das moscas e um significativo aumento do período larva recém eclodida- adulto. Além disso, o peso pupal foi reduzido e a proporção sexual alterada. Foi observada toxicidade para os ovos das moscas.

Effects of the essential oil obtained from Pilocarpus spicatus Saint-Hilaire (Rutaceae) on the development of Rhodnius prolixus nymphae

Bioassays against fifth-instar nymphae of Rhodnius prolixus were conducted with essential oil of Pilocarpus spicatus extracted by hydrodistillation. The main results may be summarized as follows: (i) high levels of toxicity and paralysis together with discrete moulting inhibition were caused by topical application of either 0.5 µL or 1.0 µL per insect of the crude essential oil; (ii) partial fagoinhibition, high moulting inhibition, prolonged intermoulting period and high number of paralyzed insects, but no toxicity were observed after oral treatment using either 5 µL or 10 µL of Pilocarpus spilcatus essential oil per mL of ingested blood meal. The importance of these results in relation to the relevant biological events in R. prolixus is herein discussed.

Bioensaios contra ninfas de 5º estádio de Rhodnius prolixus foram conduzidos utilizando-se óleo essencial de Pilocarpus spicatus extraído por hidrodestilação. Os principais resultados podem ser resumidos como se segue: (i) altos níveis de toxicidade e paralisia associados à discreta inibição da muda foram induzidos pela aplicação tópica de 0,5 µL ou 1,0 µL do óleo essencial por inseto; (ii) fagoinibição parcial, altos níveis de inibição da muda, período intermuda prolongado e alto número de insetos paralisados mas ausência de toxicidade foram observados após tratamento oral com 5,0 µL ou 10 µL de óleo essencial de P. spicatus por mL de sangue ingerido. A importância destes resultados em relação a eventos biológicos relevantes em R. prolixus é aqui discutida.